The tests and the measures (Table 4-17) component of the examination, which serves as an adjunct to the history and the systems review, involves the physical examination of the patient. The tests and the measures now currently used in physical therapy have been largely influenced by the work of a number of clinicians over the years, including Cyriax,83,88–90 Maitland,7,91 Grieve,92 Kaltenborn,5 Butler,12 Sahrmann,11 and McKenzie.93,94
Table 4-17 Tests and Measures ||Download (.pdf)
Table 4-17 Tests and Measures
Aerobic capacity and endurance
Arousal, attention, and cognition
Assistive and adaptive devices
Circulation (arterial, venous, and lymphatic)
Cranial and peripheral nerve integrity
Environmental, home, and work (job, school, and play) barriers
Ergonomics and body mechanics
Gait, locomotion, and balance
Joint integrity and mobility
Motor function (motor control and learning)
Muscle performance (strength, power, and endurance)
Neuromotor development and sensory integration
Orthotic, protective, and supportive devices
Range of motion (including muscle length)
Self-care and home management (ADLs and IADLs)
Sensory integrity (including proprioception and kinesthesia)
Ventilation and respiration and gas exchange
Work, community, and leisure integration or reintegration
The physical examination must be modified based on the history; for example, the examination of an acutely injured patient differs greatly from that of a patient in less discomfort or distress. In addition, the examination of a child differs in some respects from that of an adult (see Chap. 30).
The traditional goals of the physical examination have been to determine the structure involved, reproduce the patient's symptoms, confirm or refute the working hypothesis, and establish an objective data baseline.6,95 More recently, the focus of the examination has shifted to include the identification of impairments, functional limitations, disabilities, or changes in physical function and health status resulting from injury, disease, or other causes. This information is then used through the evaluation process to establish the diagnosis and the prognosis, and to determine the intervention.14
The physical examination must be supported by as much science as possible, so that the decision about which test(s) to use during the examination should be based on the best available research evidence. According to Sackett and colleagues,96evidence-based practice (EBP) involves the integration of best research evidence with clinical expertise and patient values. A good test must differentiate the target disorder from other disorders, with which it might otherwise be confused.97 The gathering of evidence must occur in a systematic, reproducible, and unbiased manner to select and interpret diagnostic tests and to assess potential interventions.98 The EBP process generally occurs in five steps99:
- Formulating a clinical question including details about the patient type or problem, the intervention being considered, a comparison intervention, and the outcome measure to be used.
- Searching for the best evidence, which can include a literature search on Ovid, EMBASE, PubMed, PEDro, or other medical search engine database, using the keywords from the clinical question.
- Critical appraisal of the evidence. In general, there are two types of clinical studies—those that analyze primary data and those that analyze secondary data.22 Studies that collect and analyze primary data include case reports and series and case-controls, cross-sectional, cohort (both prospective and retrospective), and randomized controlled trials.22 Analysis of second-rate data occurs in systematic reviews or meta-analysis for the purpose of pooling or synthesizing data to answer a question that is perhaps not practical or answerable within an individual study.22 Another way to broadly categorize studies is experimental, where an intervention is introduced to subjects, or observational, in which no active treatment is introduced to subjects.22
- Applying the evidence to the patient.
- Evaluation of the outcome.
The choice of which tests to use should be based on pretest probabilities, which are used to assess the diagnostic possibility of a disorder. The results from these tests are then combined with value judgments to arrive at the correct diagnosis. Unfortunately, many tests and procedures used in physical therapy practice are not, as yet, evidence based. This is particularly true with the so-called special tests (see “Special Tests”). Indeed, many of the purportedly effective special tests listed in many orthopaedic texts exhibit such poor diagnostic accuracy that only 50% of patients who have a positive test result are found to have the condition that the test is supposed to detect.98,100 Without EBP, clinicians fail to provide the consumer with scientific evidence regarding clinically effective and cost-effective practice. Throughout this text, wherever possible, the sources of evidence will be identified for each of the examination and intervention techniques described. However, in an ever-changing profession, it is ultimately the reader's responsibility to remain updated with practice recommendations and decide the appropriateness of the evidence for each of their patients in their own unique clinical setting.
The neurologic tests of the orthopaedic examination are described in Chapter 3. Before proceeding with the tests and measures, the clinician must obtain a valid consent and a full explanation must be provided to the patient as to what procedures are to be performed and the reasons for these. The chosen tests used by the clinician must be based on the patient's history or the presentation. At times, a complete examination cannot be performed. For example, if the joint to be examined is too acutely inflamed, the clinician may defer some of the examinations to the subsequent visit.
Active Physiological Range of Motion of the Extremities
Active movements of the involved area are performed before passive movements. During the history, the clinician should have deduced the general motions that aggravate or provoke the pain. Any movements that are known to be painful are performed last. The range of motion examination should be used to confirm the exact directions of motion that elicit the symptoms. The diagnosis of restricted movement in the extremities can usually be simplified by comparing both sides, provided that at least one side is uninvolved. Under normal circumstances, the normal (uninvolved) side is tested first as this allows the clinician to establish a baseline, while also showing the patient what to expect. Active range of motion testing may be deferred if small and unguarded motions provoke intense pain, because this may indicate a high degree of joint irritability, or other serious condition. The normal active range of motion for each of the joints is depicted in Table 4-18.
Table 4-18 Active Ranges of Joint Motions ||Download (.pdf)
Table 4-18 Active Ranges of Joint Motions
Degrees of Motion
Active range of motion testing gives the clinician information about the following:
- Quantity of available physiologic motion.
- Presence of muscle substitutions.
- Willingness of the patient to move.
- Integrity of the contractile and the inert tissues.
- Quality of motion. A painful arc during range of motion, with or without a painful limitation of movement, indicates the presence of a derangement.101 For example, there may be an arc of pain between 60 and 120 degrees on shoulder abduction, indicating an impingement of the structures under the acromion process or the coracoacromial ligament.
- Symptom reproduction.
- Pattern of motion restriction (e.g., capsular or noncapsular, opening or closing restriction—see later).
Capsular and Noncapsular Patterns of Restriction
Cyriax83 introduced the terms capsular and noncapsular patterns of restriction, which link impairment to pathology (Table 4-19). A capsular pattern of restriction is a limitation of pain and movement in a joint-specific ratio, which is usually present with arthritis, or following prolonged immobilization.83 It is worth remembering that a consistent capsular pattern for a particular joint might not exist and that these patterns are based on empirical findings and tradition, rather than on research.86,102
Table 4-19 Capsular Patterns of Restriction ||Download (.pdf)
Table 4-19 Capsular Patterns of Restriction
Limitation of Motion (Passive Angular Motion)
External rotation > abduction > internal rotation (3:2:1)
No true capsular pattern; possible loss of horizontal adduction and pain (and sometimes slight loss of end range) with each motion
See acromioclavicular joint
Flexion > extension (±4:1)
No true capsular pattern; possible equal limitation of pronation and supination
No true capsular pattern; possible equal limitation of pronation and supination with pain at end ranges
No true capsular pattern; possible equal limitation of pronation and supination with pain at end ranges
Flexion = extension
See wrist (carpus)
Flexion = extension
Flexion = extension
Fan > fold
Flexion > extension (±2:1)
Flexion > extension (±2:1)
Flexion > extension (±2:1)
Internal rotation > flexion > abduction = extension > other motions
Flexion > extension (±5:1)
No capsular pattern; pain at end range of translatory movements
Plantar flexion > dorsiflexion
Varus > valgus
Inversion (plantar flexion, adduction, and supination)
Extension > flexion (±2:1)
Flexion ≥ extension
Flexion ≥ extension
Flexion ≥ extension
A noncapsular pattern of restriction is a limitation in a joint in any pattern other than a capsular one and may indicate the presence of a joint derangement, a restriction of one part of the joint capsule, or an extra-articular lesion that obstructs joint motion.83
A positive finding for joint hypomobility would be a reduced range in a capsular or noncapsular pattern. The hypomobility can be painful, suggesting an acute sprain of a structure, or painless, suggesting a contracture or an adhesion of the tested structure. Significant degeneration of the articular cartilage presents with crepitus (joint noise) on movement when compression of the joint surfaces is maintained.
While abnormal motion is typically described as being reduced, abnormal motion may also be excessive. Excessive motion is often missed and is erroneously classified as normal motion. To help determine whether the motion is normal or excessive, passive range of motion (PROM), in the form of passive overpressure, and the end-feel are assessed (see next section).
Apprehension from the patient during active range of motion that limits a movement at near or full range suggests instability, whereas apprehension in the early part of the range suggests anxiety caused by pain.
Full and pain-free active range of motion suggests normalcy for that movement, although it is important to remember that normal range of motion is not synonymous with normal motion.103 Normal motion implies that the control of motion must also be present. This control is a factor of muscle flexibility, joint stability, and central neurophysiologic mechanisms. These factors are highly specific in the body.104 A loss of motion at one joint may not prevent the performance of a functional task, although it may result in the task being performed in an abnormal manner. For example, the act of walking can still be accomplished in the presence of a knee joint that has been fused into extension. Because the essential mechanisms of knee flexion in the stance period and foot clearance in the swing period are absent, the patient compensates for these losses by hiking the hip on the involved side, by side bending the lumbar spine to the uninvolved side, and through excessive motion of the foot.
Single motions in the cardinal planes are usually tested first. These tests are followed by dynamic and static testing. Dynamic testing involves repeated movements. Static testing involves sustaining a position. Sustained static positions may be used to help detect postural syndromes.101 McKenzie advocates the use of repeated movements in specific directions in the spine and the extremities. Repeated movements can give the clinician some valuable insight into the patient's condition101:
- Internal derangements tend to worsen with repeated motions.
- Symptoms of a postural dysfunction remain unchanged with repeated motions.
- Pain from a dysfunction syndrome is increased with tissue loading but ceases at rest.
- Repeated motions can indicate the irritability of the condition.
- Repeated motions can indicate to the clinician the direction of motion to be used as part of the intervention. If pain increases during repeated motion in a particular direction, exercising in that direction is not indicated. If pain only worsens in part of the range, repeated motion exercises can be used for the part of the range that is pain free or that does not worsen the symptoms.
- Pain that is increased after the repeated motions may indicate a retriggering of the inflammatory response, and repeated motions in the opposite direction should be explored.
Combined motion testing may be used when the symptoms are not reproduced with the cardinal plane motions (flexion, extension, abduction, etc.), the repeated motions, or the sustained positions. Compression and distraction also may be added to all of the active motion tests in an attempt to reproduce the symptoms.
Active Physiological Range of Motion of the Spine
Active physiologic intervertebral mobility, or active mobility, tests of the spine were originally designed by osteopaths to assess the ability of each spinal joint to move actively through its normal range of motion, by palpating over the transverse processes of a joint during the motion (see also Position Testing of the Spine). Theoretically, by palpating over the transverse processes, the clinician can indirectly assess the motions occurring at the zygapophyseal joints at either side of the intervertebral disk. However, the clinician must remember that, although it is convenient to describe the various motions of the spine occurring in a certain direction, these involve the integration of movements of a multijoint complex.
The human zygapophyseal joints are capable of only two major motions: gliding upward and gliding downward. If these movements occur in the same direction, flexion or extension of the spine occurs, while if the movements occur in opposite directions, side flexion occurs.
Osteopaths use the terms opening and closing to describe flexion and extension motions, respectively, at the zygapophyseal joint. Under normal circumstances, an equal amount of gliding occurs at each zygapophyseal joint with these motions.
- During flexion, both zygapophyseal joints glide superiorly (open).
- During extension, both zygapophyseal joints glide inferiorly (close).
- During side flexion, one joint is gliding inferiorly (closing), while the other joint is gliding superiorly (opening). For example, during right side flexion, the right joint is gliding inferiorly (closing), while the left joint is gliding superiorly (opening).
By combining flexion or extension movements with side flexion, a joint can be “opened” or “closed” to its limits. Thus, flexion and right-side flexion of a segment assesses the ability of the left joint to maximally open (flex), whereas extension and left-side flexion of a segment assesses the ability of the left joint to maximally close (extend).
There is a point that may be considered as the center of segmental rotation, about which all segmental motion must occur. In the case of a zygapophyseal joint impairment (hypermobility or hypomobility), it is presumed that this center of rotation will be altered.
If one zygapophyseal joint is rendered hypomobile (i.e., the superior facet cannot move to the extreme of superior or inferior motion), then the pure motions of flexion and extension cannot occur. This results in a relative asymmetric motion of the two superior facets, as the end of range of flexion or extension is approached (i.e., a side-flexion motion will occur). However, this side-flexion motion will not be about the normal center of segmental rotation. The structure responsible for the loss of zygapophyseal joint motion, whether it is a muscle, disk protrusion, or the zygapophyseal joint itself, will become the new axis of vertebral motion, and a new component of rotation about a vertical axis, normally unattainable, will be introduced into the segmental motion. The degree of this rotational deviation is dependent on the distance of the impairment from the original center of rotation.
Because the zygapophyseal joints in the spine are posterior to the axis of rotation, an obvious rotational change occurring between full flexion and full extension (in the position of a vertebral segment) is indicative of zygapophyseal joint motion impairment.
By observing any marked and obvious rotation of a vertebral segment occurring between the positions of full flexion and full extension, one may deduce the probable pathologic impairment.
Active motion induced by the contraction of the muscles determines the so-called physiologic range of motion,105 whereas passively performed movement causes stretching of noncontractile elements, such as ligaments, and determines the anatomic range of motion.
Passive Physiological Range of Motion of the Extremities
Passive motions are movements performed by the clinician without the assistance of the patient. Passive movements are performed in the anatomic range of motion for the joint and normally demonstrate slightly greater range of motion than active motion—the barrier to active motion should occur earlier in the range than the barrier to passive motion.
If the patient can complete the active physiological range of motion easily, without presenting pain or other symptoms, then passive testing of that motion is usually unnecessary. However, if the active motions do not reproduce the patient's symptoms, because the patient avoids going into the painful part of the range, or the active range of motion appears incomplete, it is important to perform gentle passive overpressure. Pain during passive overpressure is often due to the movement, stretching, or pinching of noncontractile structures. Pain that occurs at the mid-end range of active and passive movement is suggestive of a capsular contraction or a scar tissue that has not been adequately remodeled.101 Pain occurring at the end of PROM may be due to a stretching of the contractile structures, as well as noncontractile structures.106 Thus, PROM testing gives the clinician information about the integrity of the contractile and inert tissues, and with gentle overpressure, the end-feel. Cyriax83 introduced the concept of the end-feel, which is the quality of resistance at end range. To execute the end-feel, the point at which resistance is encountered is evaluated for quality and tenderness. Additional forces are needed as the end range of a joint is reached, and the elastic limits are challenged. This space termed the end-play zone requires a force of overpressure to be reached so that, when that force is released, the joint springs back from its elastic limits. The end-feel can indicate to the clinician the cause of the motion restriction (Tables 4-20 and 4-21).
Table 4-20 Normal End-Feels ||Download (.pdf)
Table 4-20 Normal End-Feels
Characteristics and Examples
Produced by bone-to-bone approximation
Abrupt and unyielding; gives impression that further forcing will break something
Normal: elbow extension
Abnormal: cervical rotation (may indicate osteophyte)
Produced by muscle–tendon unit; may occur with adaptive shortening
Stretches with elastic recoil and exhibits constant-length phenomenon; further forcing feels as if it will snap something
Normal: wrist flexion with finger flexion, the straight-leg raise, and ankle dorsiflexion with the knee extended
Abnormal: decreased dorsiflexion of the ankle with the knee flexed
Produced by contact of two muscle bulks on either side of a flexing joint where joint range exceeds other restraints
Very forgiving end-feel that gives impression that further normal motion is possible if enough force could be applied
Normal: knee flexion and elbow flexion in extremely muscular subjects
Abnormal: elbow flexion with obese subject
Produced by capsule or ligaments
Various degrees of stretch without elasticity; stretch ability is dependent on thickness of tissue
Strong capsular or extracapsular ligaments produce hard capsular end-feel, whereas thin capsule produces softer one
Impression given to clinician is that if further force is applied, something will tear
Normal: wrist flexion (soft), elbow flexion in supination (medium), and knee extension (hard)
Abnormal: inappropriate stretch ability for specific joint; if too hard, may indicate hypomobility due to arthrosis; and if too soft, hypermobility
Table 4-21 Abnormal End-Feels ||Download (.pdf)
Table 4-21 Abnormal End-Feels
Characteristics and Examples
Produced by articular surface rebounding from intra-articular meniscus or disk; impression is that if forced further, something will give way
Rebound sensation as if pushing off from a rubber pad
Normal: axial compression of cervical spine
Abnormal: knee flexion or extension with displaced meniscus
Produced by viscous fluid (blood) within joint
“Squishy” sensation as joint is moved toward its end range; further forcing feels as if it will burst joint
Abnormal: hemarthrosis at knee
Produced by reflex and reactive muscle contraction in response to irritation of nociceptor, predominantly in articular structures and muscle; forcing it further feels as if nothing will give
Abrupt and “twangy” end to movement that is unyielding while the structure is being threatened but disappears when threat is removed (kicks back)
With joint inflammation, it occurs early in range, especially toward close-packed position, to prevent further stress
With irritable joint hypermobility, it occurs at end of what should be normal range, as it prevents excessive motion from further stimulating the nociceptor
Spasm in grade II muscle tears becomes apparent as muscle is passively lengthened and is accompanied by a painful weakness of that muscle
Note: Muscle guarding is not a true end-feel, as it involves co-contraction
Abnormal: significant traumatic arthritis, recent traumatic hypermobility, and grade II muscle tears
Produced solely by pain; frequently caused by serious and severe pathologic changes that do not affect joint or muscle and so do not produce spasm; demonstration of this end-feel is, with exception of acute subdeltoid bursitis, de facto evidence of serious pathology; further forcing simply increases pain to unacceptable levels
Limitation of motion has no tissue resistance component, and resistance is from patient being unable to tolerate further motion due to severe pain; it is not same feeling as voluntary guarding, but rather it feels as if patient is both resisting and trying to allow movement simultaneously
Abnormal: acute subdeltoid bursitis and sign of the buttock
Not truly an end-feel, as facilitated hypertonicity does not restrict motion; it can, however, be perceived near end range
Light resistance as from constant light muscle contraction throughout latter half of range that does not prevent end of range being reached; resistance is unaffected by rate of movement
Abnormal: spinal facilitation at any level
One study that looked at the intra- and inter-rater reliability of assessing end-feel, and pain and resistance sequence in subjects with painful shoulders and knees, found the end-feel to have good intrarater reliability, but unacceptable inter-rater reliability.86
Although some clinicians feel that overpressure should not be applied in the presence of pain, this is erroneous. Most, if not all, of the end-feels that suggest acute or serious pathology are to be found in the painful range, including spasm and the empty end-feel.
The end-feel is very important in joints that have only very small amounts of normal range, such as those of the spine. The type of end-feel can help the clinician determine the presence of dysfunction. For example, a hard, capsular end-feel indicates a pericapsular hypomobility, whereas a jammed or a pathomechanical end-feel indicates a pathomechanical hypomobility. A normal end-feel would indicate normal range, whereas an abnormal end-feel would suggest abnormal range, either hypomobile or hypermobile. An association between an increase in pain and abnormal pathologic end-feels compared with normal end-feels has been demonstrated.107
The planned intervention, and its intensity, is based on the type of tissue resistance to movement, demonstrated by the end-feel, and on the acuteness of the condition (Table 4-22).83 This information may indicate whether the resistance is caused by pain, muscle, capsule ligament, disturbed mechanics of the joint, or a combination.
Table 4-22 Abnormal Barriers to Motion and Recommended Manual Techniques ||Download (.pdf)
Table 4-22 Abnormal Barriers to Motion and Recommended Manual Techniques
Oscillations (I, IV)
Passive articular motion stretch (I–V)
Passive physiologic motion stretch
Muscle energy (Hold/relax, etc.)
According to Cyriax, if active and passive motions are limited or painful in the same direction, the lesion is in an inert tissue, whereas if the active and passive motions are limited or painful in the opposite direction, the lesion is in a contractile tissue.83
The quantity and quality of movement refer to the ability to achieve end-range without deviation from the intended movement plane.
Both the passive and active physiological ranges of motion can be measured using a goniometer, which has been shown to have a satisfactory level of intraobserver reliability.108–110 Visual observation in experienced clinicians has been found to be equal to measurements by goniometry.111
The recording of range of motion varies. The American Medical Association recommends recording the range of motion on the basis of the neutral position of the joint being zero, with the degrees of motion increasing in the direction the joint moves from the zero starting point.112 A plus sign (+) is used to indicate joint hyperextension and a minus sign (–) to indicate an extension lag. The method of recording chosen is not important, provided the clinician chooses a recognized method and documents it consistently with the same patient.
Passive Physiological Range of Motion of the Spine
The passive physiologic intervertebral mobility, or passive mobility, tests use the same principles as the active physiologic intervertebral mobility tests to assess the ability of each joint in the spine to move passively through its normal range of motion, while the clinician palpates over the interspinous spaces. During extension, the spinous processes should approximate, whereas during flexion, they should separate.
If pain is reproduced, it is useful to associate the pain with the onset of tissue resistance to gain an appreciation of the acuteness of the problem. The passive mobility tests of the spine are described in the appropriate chapters.
The examination of flexibility is performed to determine if a particular structure, or group of structures, has sufficient extensibility to perform a desired activity. The extensibility and habitual length of connective tissue are factors of the demands placed upon it. These demands produce changes in the viscoelastic properties and, thus, the length–tension relationship of a muscle or muscle group, resulting in an increase or a decrease in the length of those structures. A decrease in the length of the soft-tissue structures, or adaptive shortening, is very common in postural dysfunctions. Adaptive shortening also can be produced by
- restricted mobility;
- tissue damage secondary to trauma;
- prolonged immobilization;
- hypertonia. Hypertonic muscles that are superficial can be identified through observation and palpation. Observation will reveal the muscle to be raised, and light palpation will provide information about tension, as the muscle will feel hard and may stand out from those around it.
Flexibility can be measured objectively using standardized tests, or a goniometer. A more subjective test for flexibility includes an examination of the end-feel, which can detect a loss of motion resulting from excessive tension of the agonist muscle. Visual observation, which has been found to have a variability of 30% in patients with low back pain and sciatica, may also be used.113
Joint Integrity and Mobility
Joint integrity and mobility testing can provide valuable information about the status and the mobility of each joint and its capsule. Kaltenborn5 introduced the concept of motion restriction of a joint based on its arthrokinematics. In order for a joint to function completely, both the osteokinematic and arthrokinematic motions have to occur normally (see Chap. 1). It, therefore, follows that if a joint is not functioning completely, either the physiologic range of motion is limited compared with the expected norm or there is no PROM available between the physiologic barrier and the anatomic barrier. As previously mentioned, the assessment of the end-feel can help determine the cause of the restriction.57 In general, the physiologic motion is controlled by the contractile tissues, whereas the accessory motion is controlled by the integrity of the joint surfaces and the noncontractile (inert) tissues. This guideline may change in the case of a joint that has undergone degenerative changes, which can result in a decrease in the physiologic motions (capsular pattern of restriction). It is important that the intervention to restore the complete function of the joint be aimed at the specific cause.
Joint pain and dysfunction do not occur in isolation.114,115 Various measurement scales have been proposed for judging the amount of accessory joint motion present between two joint surfaces (see Chap. 10), most of which are based on a comparison with a comparable contralateral joint, using manually applied forces in a logical and precise manner.116 In the extremities, these tests are referred to as passive articular mobility, or joint glide tests. In the spine, these tests are referred to as the passive physiologic accessory intervertebral motion testing.
In general, if the concave-on-convex glide (see Chap. 1) is restricted, there is a contracture of the trailing portion of the capsule, whereas if the convex-on-concave glide is restricted, there is an inability of the moving surface to glide into the contracted portion of the capsule.
The passive articular mobility tests involve the clinician assessing the arthrokinematic, or accessory, motions using joint glides, and determining whether the glide is hypomobile, normal, or hypermobile (see Chap. 2).5–7
Accessory motions are involuntary motions. With few exceptions, muscles cannot restrict the glides of a joint, especially if the glides are tested in the open-packed position of a peripheral joint and, at the end of available range, in the spinal joints.
Thus, if the clinician assesses the accessory motion of the joint by performing a joint glide, information about the integrity of the inert structures will be given. There are two scenarios:
The joint glide is unrestricted. An unrestricted joint glide indicates two differing conclusions:
a. The integrity of both the joint surface and the periarticular tissue is good. If the joint surface and the periarticular structures are intact, the patient's loss of motion must be the result of a contractile tissue. The intervention for this type involves soft-tissue mobilization techniques designed to change the length of a contractile tissue.
b. The joint glide is unrestricted but excessive. The excessive motion may indicate a pathological hypermobility or instability, or it may be normal for the individual. In these cases, the end-feel can provide some useful information. The intervention for this type concentrates on stabilizing techniques designed to give secondary support to the joint through muscle action.
The joint glide is restricted. If the joint glide is restricted, the joint surface and the periarticular tissues are implicated as the cause of the patient's loss of motion, although as previously mentioned, the contractile tissues cannot definitively be ruled out. The intervention for this type of finding initially involves a specific joint mobilization to restore the glide. Once the joint glide is restored following these mobilizations, the osteokinematic motion can be assessed again. If it is still reduced, the contractile tissues are likely to be at fault. Distraction and compression can be used to help differentiate the cause of the restriction.
Distraction. Traction is a force imparted passively by the clinician that results in a distraction of the joint surfaces.
If the distraction is limited, a contracture of connective tissue should be suspected.
- If the distraction increases the pain, it may indicate a tear of connective tissue and may be associated with increased range.
- If the distraction eases the pain, it may indicate an involvement of the joint surface.
Compression. Compression is the opposite force to distraction, and involves an approximation of joint surfaces.
- If the compression increases the pain, a loose body or an internal derangement of the joint may be present.
- If the compression decreases the pain, it may implicate the joint capsule.
Thus, by assessing these joint motions, the clinician can determine the
- cause of a limitation in a joint's physiologic range of motion;
- end-feel response of the tissues;
- stage of healing;
- integrity of the support structures (e.g., ligaments) of a joint (for example, the integrity of the anterior cruciate ligament is tested with the Lachman test).
Based on the information gleaned from the joint glide assessment, the clinician makes clinical decisions as to which intervention to use. If the joint glide is felt to be restricted, and there is no indication of a bony end-feel or severe irritability, joint mobilization techniques are used. If the joint glide is found to be unrestricted, the clinician may decide to employ a technique that increases the extensibility of the surrounding connective tissues, such as muscle energy, because abnormal shortness of these connective tissues, including the ligaments, the joint capsule, and the periarticular tissues, can restrict joint mobility.
Caution must be used when basing clinical judgments on the results of accessory motion testing, because few studies have examined the validity and reliability of accessory motion testing of the spine or extremities and little is known about the validity of these tests for most inferences.116 A study of the predicted value of positive and negative test results in addition to the sensitivity and specificity of the various tests would be of value.116
Position Testing in the Spine
The position tests are screening tests designed by osteopaths to examine the relative position of a zygapophyseal joint, or joints, to the joint(s) below (see appropriate chapters). As with all screening tests, position testing is valuable in focusing the attention of the clinician to a specific area but is not appropriate for making a definitive statement concerning the movement status of the segment. However, when combined with the results of the passive and active movement testing, position tests help to form the working hypothesis.
Muscle Performance: Strength, Power, and Endurance
Strength measures the power with which musculotendinous units act across a bone-joint lever-arm system to actively generate motion, or passively resist movement against gravity and variable resistance.112
According to Cyriax, pain with a contraction generally indicates an injury to the muscle or a capsular structure.83 This suspicion can be confirmed by combining the findings from the isometric test with the findings of the passive motion and the joint distraction and compression tests (Table 4-23). Cyriax reasoned that if you isolate and then apply tension to a structure, you can make a conclusion as to the integrity of that structure.83 His work also introduced the concept of tissue reactivity. Tissue reactivity is the manner in which different stresses and movements can alter the clinical signs and symptoms. This knowledge can be used to gauge any subtle changes to the patient's condition.117
Table 4-23 Differential Diagnosis of Contractile, Inert, and Neural Tissue Injury ||Download (.pdf)
Table 4-23 Differential Diagnosis of Contractile, Inert, and Neural Tissue Injury
Cramping, dull, and ache
Burning and lancinating
Peripheral nerve sensory distribution
Yes (if peripheral nerve involved)
Boggy and hard capsular
In addition to examining the integrity of the contractile and inert structures, strength testing may be used to examine the integrity of the key muscles (see Chap. 3). Pain with muscle testing may indicate a muscle injury, a joint injury, or a combination of both. Pain that occurs consistently with resistance, at whatever the length of the muscle, may indicate a tear of the muscle belly. Weakness with muscle testing must be differentiated between weakness throughout the range of motion (pathological weakness) and weakness that only occurs in certain positions (positional weakness). According to Cyriax,83,89 strength testing can provide the clinician with the following findings:
- A weak and painless contraction may indicate palsy or a complete rupture of the muscle–tendon unit. The motor disorder associated with peripheral neuropathy is first manifested by weakness and a diminished or absent tendon reflex (see Chap. 3).49
- A strong and painless contraction indicates a normal finding.
- A weak and painful contraction. A study by Franklin and colleagues87 indicated that the conditions related to this finding need to include not only serious pathology, such as a significant muscle tear or a tumor, but relatively minor muscle damage and inflammation such as that induced by eccentric isokinetic exercise.106
- A strong and painful contraction indicates a grade I contractile lesion.
Pain that does not occur during the test, but occurs upon the release of the contraction, is thought to have an articular source, produced by the joint glide that occurs following the release of tension.
Pain that occurs with resistance, accompanied by pain at the opposite end of passive range, indicates muscle impairment.
The degree of certainty regarding the findings just described depends on a combination of the length of the muscle tested and the force applied. To fully test the integrity of the muscle–tendon unit, a maximum contraction must be performed in the fully lengthened position of the muscle–tendon unit. Although this position fully tests the muscle–tendon unit, there are some problems with testing in this manner:
- The joint and its surrounding inert tissues are in a more vulnerable position and could be the source of the pain.
- It is difficult to differentiate between damage to the contractile tissue of varying severity. The degree of significance with the findings in resistive testing depends on the position of the muscle and the force applied (Table 4-24). For example, pain reproduced with a minimal contraction in the rest position for the muscle is more strongly suggestive of a contractile lesion than pain reproduced with a maximal contraction in the lengthened position for the muscle.
- As a muscle lengthens, it reaches a point of passive insufficiency, where it is not capable of generating its maximum force output (see Chap. 1).
Table 4-24 Strength Testing Related to Joint Position and Muscle Length ||Download (.pdf)
Table 4-24 Strength Testing Related to Joint Position and Muscle Length
Muscle in position of passive insufficiency
Tightens the inert component of the muscle
Tests for muscle tears (tendoperiosteal tears) while using minimal force
Muscle in strongest position
Tests overall power of muscle
Muscle in its weakest position
Used for the detection of palsies, especially if coupled with an eccentric contraction
If the same muscle is tested on the opposite side, using the same testing procedure, the concern about the length of the muscle is removed, because the focus of the test is to provide a comparison with the same muscle on the opposite side, rather than to assess the absolute force output.
To assess strength, strength values using manual muscle testing (MMT) have traditionally been used between similar muscle groups on opposite extremities, or antagonistic ratios. This information is then used to determine whether a patient was fully rehabilitated. It should be noted that there is considerable variability in the amount of resistance that normal muscles can hold against. The application of resistance throughout the arc of motion (make test or active resistance test) in addition to resistance applied at only one point in the arc of motion (break test) can help in judging the strength of a muscle.106 During all testing, stabilization of the body part on which the muscle originates in addition to careful avoidance of substitution by other muscle groups are emphasized. Substitutions by other muscle groups during testing indicate the presence of weakness. It does not, however, tell the clinician the cause of the weakness.
MMT has been shown to be less sensitive in detecting strength deficits in stronger muscles than in weaker muscles.106
Several scales have been devised to assess muscle strength. For example, Janda118 used a 0–5 scale with the following descriptions:
- Grade 5: N (normal). A normal, very strong muscle with a full range of movement and one that is able to overcome considerable resistance. This does not mean that the muscle is normal in all circumstances (e.g., when at the onset of fatigue or in a state of exhaustion). If the clinician is having difficulty differentiating between a grade 4 and a grade 5, the eccentric “break” method of muscle testing may be used. This procedure starts as an isometric contraction, but then the clinician applies sufficient force to cause an eccentric contraction or a “break” in the patient's isometric contraction.
- Grade 4: G (good). A muscle with good strength and full range of movement, and one that is able to overcome moderate resistance. The subjectivity involved in a grade 4 score is one of the major criticisms of MMT as the grading requires the clinician to assign an ordinal number to a subjective evaluation of resistance offered by the patient.
- Grade 3: F (fair). A muscle that can move through the complete range of movement against gravity only with no additional resistance applied. If the muscle strength is less than grade 3, then the methods advocated in muscle testing manuals must be used.106
- Grade 2: P (poor). A very weak muscle that is only able to move through the complete range of motion if the force of gravity is eliminated.
- Grade 1: T (trace). A muscle with evidence of slight contractility but demonstrates no effective movement.
- Grade 0. A muscle with no evidence of any contractility.
The grading systems for MMT produce ordinal data with unequal rankings between grades. For example, the grades 5 (normal) and 4 (good) typically encompass a large range of a muscle's strength, while the grades of 3 (fair), 2 (poor), and 1 (trace) include a much narrower range.106 If the popular methods to grade muscles are analyzed, the frailties and similarities become obvious. If the muscle strength is less than grade 3, these testing grades are useful, but it is the grades of 3 and higher that produce the most confusion. Some of the confusion arises from the descriptions of maximal, moderate, and minimal, or considerable, which removes much of the objectivity from the tests.
Studies have demonstrated that reliability in MMT is dependent on the specific muscle being examined. For example, Florence and colleagues119 found high reliability in the proximal muscles as opposed to the distal muscles, and Barr and colleagues120 found the upper body muscles to be more reliably tested than the lower body ones.121
To be a valid test, strength testing must elicit a maximum contraction of the muscle being tested. The following strategies ensure that this occurs:
Placing the joint that the muscle to be tested crosses, in (or close to) its open-packed position. This strategy helps protect the joint from excessive compressive forces, and the surrounding inert structures from excessive tension.
Placing the muscle to be tested in a shortened position. This puts the muscle in an ineffective physiologic position and has the effect of increasing motor neuron activity.
Using gravity-minimized positions. This strategy avoids the effect of the weight of the moving body segment on force measurements. For example, to test the strength of the hip abductors, the patient is positioned in supine so that the muscle action pulls in a horizontal plane relative to the ground.106
Having the patient perform an eccentric muscle contraction by using the command “Don't let me move you.” Because the tension at each cross-bridge and the number of active cross-bridges is greater during an eccentric contraction, the maximum eccentric muscle tension developed is greater with an eccentric contraction than with a concentric one.
Breaking the contraction. It is important to break the patient's muscle contraction, in order to ensure that the patient is making a maximal effort and that the full power of the muscle is being tested. Although force values determined with make and break tests are highly correlated, break tests usually result in greater force values than make tests,122,123 so they should not be used interchangeably.
Holding the contraction for at least 5 seconds. Weakness resulting from nerve palsy has a distinct fatigability. The muscle demonstrates poor endurance, because usually it is only able to sustain a maximum muscle contraction for about 2–3 seconds before complete failure occurs. This strategy is based on the theories behind muscle recruitment, wherein a normal muscle, while performing a maximum contraction, uses only a portion of its motor units, keeping the remainder in reserve to help maintain the contraction. A palsied muscle, with its fewer functioning motor units, has very few, if any, motor units in reserve. If a muscle appears to be weaker than normal, further investigation is required, as follows:
- a. The test is repeated three times. Muscle weakness resulting from disuse will be consistently weak and should not become weaker with several repeated contractions. In contrast, a palsied muscle becomes weaker with each contraction.
- b. Another muscle that shares the same innervation is tested. Knowledge of both spinal and peripheral nerve innervation will aid the clinician in determining which muscle to select (see Chap. 3).
Comparing findings with uninvolved side. One study found no statistically significant difference in force between the dominant and nondominant lower extremities, but did find the difference between the dominant and nondominant upper extremities.124 Sapega125 recommends that the difference in muscle force between sides of greater than 20% probably indicates abnormality, while the difference of 10 to 20% possibly indicates abnormality.
As always, these tests cannot be evaluated in isolation but have to be integrated into a total clinical profile, before drawing any conclusion about the patient's condition.
MMT is an ordinal level of measurement125 and has been found to have both inter- and intra-rater reliability, especially when the scale is expanded to include plus or minus a half or a full grade.18,126,127 Training in standardized testing positions, stabilization, and grading criteria resulted in higher agreement and correlation coefficients between testers.
Although the grading of muscle strength has its role in the clinic, and the ability to isolate the various muscles is very important in determining the source of nerve palsy, specific grading of individual muscles does not give the clinician much information on the ability of the structure to perform functional tasks. In addition, measurements of isometric muscle force are specific to a point or small range in the joint range excursion and, thus, cannot be used to predict dynamic force capabilities.128–130
More recently, the use of quantitative muscle testing (QMT) has been recommended to assess strength, as it produces interval data that describe force production. QMT methods include:
- The use of handheld dynamometers. Although more costly and time consuming than MMT, handheld dynamometry can be used to improve objectivity and sensitivity. Patients are typically asked to push against the dynamometer with a maximal isometric contraction (make test), or hold a position until the clinician and the dynamometer overpower the muscle producing an eccentric contraction (break tests).106 Normative force values for particular muscle groups by patient age and gender have been reported, with some authors including regression equations that take into account body weight and height.131
- The use of an isokinetic dynamometer. This is a stationary, electromechanical device that controls the velocity of the moving body segment by resisting and measuring the patient's effort so that the body segment cannot accelerate beyond a preset angular velocity.106 Isokinetic dynamometers measure torque and range of motion as a function of time, and can provide an analysis of the ratio between the eccentric contraction and concentric contraction of a muscle at various positions and speeds.137 This ratio is aptly named the eccentric/concentric ratio.138 The ratio is calculated by dividing the eccentric strength value by the concentric strength value. Various authors139,140 have demonstrated that the upper limit of this ratio is 2.0 and that lower ratios indicate pathology.138,141 Alternatively, the same recommendations for MMT advocated by Sapega125 can be used: a difference in muscle force between sides of greater than 20% probably indicates abnormality, while the difference of 10–20% possibly indicates abnormality. To ensure the validity of isokinetic dynamometry measurements, calibration of equipment is necessary and should be performed each day of testing, at the same speed and damp setting during the testing.142
Depending on the study, handheld dynamometers have demonstrated good to excellent intra-tester reliability and poor to excellent inter-tester reliability.132–136
One of the major criticisms of muscle testing is the over estimation of strength when a muscle is weak as identified by QMT, compared to the same muscle being graded as normal by MMT, such that a theoretical percentage score based on MMT is likely to grossly overestimate the strength of a patient.121 For example, Beasley143 showed that 50% of knee extensor strength needed to be lost before MMT was able to identify weakness.
Studies that compare the reliability of MMT and QMT often come to the conclusion that MMT may be consistent and reliable, but it is unable to detect subtle differences in strength.144,145 Thus, although MMT results are more consistent, the variation produced by QMT can appreciate differences in strength undetectable in MMT.121
Regardless of the type of muscle testing used, the procedure is innately subjective and depends on the subject's ability to exert a maximal contraction. This ability can be negatively impacted by such factors as pain, poor comprehension, motivation, cooperation, fatigue, and fear.
Voluntary muscle strength testing will remain somewhat subjective until a precise way of measuring muscle contraction is generally available.112 This is particularly true when determining normal and good values.
Motor function is the ability to demonstrate the skillful and efficient assumption, maintenance, modification, and control of voluntary postures and movement patterns.14 The criteria for simple motor patterns are that the movement69,118
- is performed exactly in the desired direction;
- is smooth and of a constant speed;
- follows the shortest and most efficient path;
- is performed in its full range.
The criteria for complex motor patterns are as follows69:
- Synchronization between the primary movers in the distal regions with those more proximal.
- Smooth propagation of motion from one region of the body to another.
- Absence of inefficient movement patterns or muscle recruitment.
- Optimal relationships between the speed of motion initiated in one region and the speed of motion in other regions.
Indications of a systemic neurologic compromise that has impacted motor function include abnormal movement patterns, movement synergies, or gait disturbances. Primitive movement patterns are those seen with compromise to the CNS, such as the flexor withdrawal pattern.146
The upper extremities can work together, when they are in direct or indirect contact with each other (clasping the hands together or holding an object with two hands), or separately. The lower extremities can work together off a stable base or separately. In the bilateral combinations, the two limbs are separated, but both are involved in the activity. The limbs may be moved in the same direction, termed symmetric (breaststroke swimming); in opposite directions, termed reciprocal (swimming the crawl); toward one side of the body (pulling on a rope above one side of the head), termed asymmetric; or toward opposite sides of the body (swimming side stroke), termed cross-diagonal or reciprocal asymmetric.147
Mass movement patterns involve combined motions of the joints within the kinetic chain, depending on the desired motion.148 For example, a mass pattern of the lower extremity could involve hip, knee, and ankle dorsiflexion, with the rotation and abduction–adduction component varying. Advanced movement patterns involve such combinations as hip extension, knee flexion, and plantar flexion, or hip flexion, knee extension, and dorsiflexion—motions that occur with normal gait.148
Aerobic Capacity and Endurance
Aerobic capacity endurance is the ability to perform work or participate in activity over time, using the body's oxygen uptake, delivery, and energy-release mechanisms (see Chap. 15).14 Clinical indications for the use of the tests and measures for this category are based on the findings from the history and systems review. These indications include, but are not limited to, pathology, pathophysiology, and impairment to14:
- cardiovascular system (e.g., abnormal heart rate, rhythm, and blood pressure);
- endocrine/metabolic system (e.g., osteoporosis);
- multiple systems (e.g., trauma and systemic disease);
- neuromuscular system (e.g., generalized muscle weakness and decreased endurance);
- pulmonary system (e.g., abnormal respiratory pattern, rate, and rhythm).
The aerobic capacity and endurance of a patient can be measured using standardized exercise test protocols (e.g., ergometry, step tests, time or distance walk or run tests, and treadmill tests) and the patient's response to such tests.14
Anthropometric characteristics are traits that describe body dimensions, such as height, weight, girth, and body fat composition.14 The use of an anthropometric examination and the subsequent measurements varies. Clearly, if a noticeable amount of effusion or swelling is present, these measurements serve as an important baseline from which to judge the effectiveness of the intervention.
Circulation is defined by The Guide as the movement of blood through organs and tissues to both deliver oxygen and remove carbon dioxide and cellular byproducts.14 Circulation also involves the passive movement of lymph through channels. The examination of the circulation includes an examination of those cardiovascular signs not tested in the aerobic capacity and endurance portion, and the anthropometric characteristics portion of the examination, including the patient's physiologic response to position change, an inspection of the nail beds, capillary refill, and monitoring of the pulses of the extremities.
In general, the posterior (dorsal) pedis pulse is used in the lower extremities to assess the patency of the lower extremity vessels, whereas the radial pulse is used for the upper extremities.
Work, Environmental, and Home Barriers (Job, School, and Play)
Work, environmental, and home barriers are the physical impediments that keep patients from functioning optimally in their surroundings.14
Ergonomics and Body Mechanics
Ergonomics is the relationship among the worker; the work that is done; the actions, tasks, or activities inherent in that work (job, school, and play); and the environment in which the work (job, school, and play) is performed.14 Body mechanics are the interrelationships of the muscles and joints, as they maintain or adjust posture in response to forces placed on or generated by the body.
It is not within the scope of this text to detail the scientific and engineering principles related to ergonomics and the numerous tests used to quantify these measures. Ergonomics as it relates to posture is discussed within the related chapters.
Gait, Locomotion, and Balance
Gait analysis is an important component of the examination process (see Chap. 6) and should not be reserved only for those patients with lower extremity dysfunction. Although the act of walking is often taken for granted, normal and reciprocal gait requires a finely tuned series of reflexes.149 The examination of gait is performed to highlight any breakdown within these reflexes, including imbalances of flexibility or strength, or compensatory motions.150
Gait, like posture, varies between individuals, and a gait that differs from normal is not necessarily pathologic. The analysis of gait is described in Chapter 6.
Balance is an essential component for participation in sports and for activities of daily living (see Chap. 3). During the history, the patient may describe symptoms of dizziness, lightheadedness, a sense of impending faint, or poor balance. Ataxia is a discoordination or clumsiness of movement that is not associated with muscular weakness, but has very strong associations with CNS dysfunction (see Chap. 3).151 A sudden onset of unilateral deafness may be due to labyrinth artery infarction, possibly indicating an infarction in the vertebrobasilar system,152 Ménière's disease, acoustic neuroma, autoimmune disease of the inner ear, Friedrich's ataxia, vestibulocochlear nerve compression, diabetes mellitus, otosclerosis, or an adverse drug reaction.153 Nausea and vomiting are common complaints in balance disorders. The assessment of balance is discussed in Chapter 3.
Orthotic, Adaptive, Protective, and Assistive Devices
These devices are implements and equipments used to support or protect weak or ineffective joints or muscles and serve to enhance performance.14 Examples of such devices include canes, crutches, walkers, reachers, and ankle foot orthoses.
Posture describes the relative positions of different joints at any given moment.46 The postural examination gives an overall view of the patient's muscle function in both chronic and acute pain states. The examination enables the clinician to differentiate between possible provocative causes, such as structural variations, altered joint mechanics, muscle imbalances, and the residual effects of pathology. The assessment of posture is detailed in Chapter 6 and in the relevant chapters.
Work (Job, School, and Play), Community, and Leisure Integration and Reintegration
In short, this category refers to the process of assuming or resuming roles and functions.
Self-Care and Home Management (Including Activities of Daily Living and Instrumental Activities of Daily Living)
This portion of the examination addresses the patient's perception of his or her condition, namely issues regarding the patient's perception on their functional level and quality of life.
Once the examination is complete, the clinician should be able to add and subtract the various findings, determine the accuracy of the working hypothesis, and make an evaluation, which involves developing the diagnosis, the prognosis, and the realistic POC.168 According to Grieve,92 an evaluation is the level of judgment necessary to make sense of the findings, in order to identify a relationship between the symptoms reported and the signs of disturbed function. Thus, while the evaluation is used to determine the diagnosis, the prognosis, and the POC, it is the diagnosis that guides the intervention.
The diagnosis and the prognosis are critical to shaping the final POC. A physical therapy diagnosis refers to the cluster of signs and symptoms, syndromes, or categories and is used to guide the physical therapist in determining the most appropriate intervention strategy for each patient.169
Patients may be referred to physical therapy with a nonspecific diagnosis, an incorrect diagnosis, or no diagnosis at all.170 Physical therapists are responsible for thoroughly examining each patient and then either treating the patient according to established guidelines, or referring the patient to a more appropriate healthcare provider.171 A diagnosis can only be made when all potential causes for the signs and symptoms have been ruled out, so the clinician should resist the urge to categorize a condition based on a small number of findings. The best indicator for the correctness of a diagnosis is the quality of the hypothesis considered, because if the appropriate diagnosis is not considered from the start, any subsequent inquiries will be misdirected.172 Ultimately, given the role of physical therapists as movement specialists, task analysis should form the basis of the diagnosis.173 Once impairments have been highlighted, a determination can be made as to the reason for those impairments, and the relationship between the impairments and the patient's functional limitations or disabilities.
Decision making encompasses the selection of tests during the examination process, interpretation of data from the detailed history and examination, establishment of the diagnosis, estimation of the prognosis, determination of intervention strategies, sequence of therapeutic procedures, and establishment of discharge criteria.169 The decision-making process is a multifaceted fluid process which combines tacit knowledge with accumulated clinical experience.174 The experienced clinician is able to recognize patterns and extrapolate information from them using forward reasoning, to develop an accurate working hypothesis.175 This is accomplished through an estimate of the proportional contribution of tissue pathology and impairment clusters to the patient's functional limitations.20 Using this information, the clinician puts a value on examination findings, considering relevant environmental, social, cultural, psychological, medical, and physical findings and clusters the information into recognizable, understandable, or identifiable diagnoses, dysfunctions, or classification syndromes.20 According to Kahney,176 the expert seems to do less problem solving than the novice, because the former has already stored solutions to many of the clinical problems previously encountered.177
One of the problems for the clinician is how to attach relevance to all of the information gleaned from the examination. This judgment process can be viewed as a continuum. At one end of the continuum is the novice who uses very clear-cut signposts, while at the other end there is the experienced clinician who has a vast bank of clinical experiences from which to draw.177 Experts are able to see meaningful relationships, possess enhanced memory, are skilled in qualitative analysis, and have well-developed reflection skills.174 This combination of skills allows the expert to systematically organize the information to make efficient and effective clinical decisions.
What differentiates diagnosis by the physical therapist from diagnosis by the physician is not the process itself but the phenomena being observed and clarified.178 Sackett et al.98 proposed three strategies of clinical diagnosis:
- Pattern recognition. This is characterized by the clinician's instantaneous realization that the patient conforms to a previously learned pattern of disease.
- History and physical examination. This method requires the clinician to consider all hypotheses of the potential etiology.
- Hypothetico-deductive method. In this method, the clinician identifies early clues and formulates a short list of potential diagnoses.
The clinician's knowledge base is critical in the evaluation process.172 Experienced clinicians appear to have a superior organization of knowledge, and they use a combination of hypothetico-deductive reasoning and pattern recognition to derive the correct diagnosis or working hypothesis.172
A number of frameworks have been applied to clinical practice for guiding clinical decision making and providing structure to the healthcare process.179–185 While the early frameworks were based on disablement models, the more recent models have focused on enablement perspectives using algorithms. An algorithm is a systematic process involving a finite number of steps that produces the solution to a problem. Algorithms used in healthcare allow for clinical decisions and adjustments to be made during the clinical reasoning and decision-making process because they are not prescriptive or protocol driven.174 The most commonly used algorithm in physical therapy is the hypothesis-oriented algorithm for clinicians (HOAC) designed by Rothstein and Echternach.182 The HOAC is designed to guide the clinician from evaluation to intervention planning with a logical sequence of activities, and requires the clinician to generate working hypotheses early in the examination process, the latter of which is a strategy often used by expert clinicians.
When integrating evidence into clinical decision making, an understanding of how to appraise the quality of the evidence offered by clinical studies is important. One of the major problems in evaluating studies is that the volume of literature makes it difficult for the busy clinician to obtain and analyze all of the evidence necessary to guide the clinical decision-making process.16 The other problem involves deciding whether the results from the literature are definite enough to indicate an effect other than chance. Judging the strength of the evidence becomes an important part of the decision-making process.
Clinical prediction rules (CPRs) are tools designed to assist clinicians in decision making when caring for patients. However, although there is a growing trend toward producing a number of CPRs in the field of physical therapy, few CPRs presently exist (see Chap. 8).
The standard for the assessment of the efficacy and value of a test or intervention is the clinical trial, that is, a prospective study assessing the effect and value of a test or intervention against a control in human subjects.186 Unfortunately, many of the experimental studies that deal with physical therapy topics are not clinical trials, because there is no control to judge the efficacy of the test or intervention, and there are no tests or interventions from which to draw comparisons.187 The best evidence for making decisions about interventions comes from randomized controlled trials, systematic reviews, and evidence based clinical practice guidelines (Table 4-25).188 The ideal clinical trial includes a blinded, randomized design and a control group. It may be possible to discriminate between high- and low-quality trials by asking three simple questions188:
Were subjects randomly allocated to conditions? Random allocation implies that a nonsystematic, unpredictable procedure was used to allocate subjects to conditions.
Was there blinding of assessors and patients? Blinding of assessors and patients minimizes the risk of the placebo effect and the “Hawthorne effect,” an experimental artifact that is of no clinical utility, where patients report better outcomes than they really experienced because they perceive that this is what is expected from them.189
Was there adequate follow-up? Ideally, all subjects who enter the trial should subsequently be followed up to avoid bias. In practice, this rarely happens. As a general rule, losses to follow-up of less than 10% avoid serious bias, but losses to follow-up of more than 20% cause potential for serious bias.
Table 4-25 Randomized Controlled Trials, Systematic Reviews, and Clinical Practice Guidelines ||Download (.pdf)
Table 4-25 Randomized Controlled Trials, Systematic Reviews, and Clinical Practice Guidelines
Randomized controlled trials (RCTs)
Involve experiments on people.
Less exposed to bias.
Ensures comparability of groups.
Typically, volunteers agree to be randomly allocated to groups receiving one of the following:
- Treatment and no treatment
- Standard treatment and standard treatment plus a new treatment
- Two alternate treatments
The common feature is that the experimental group receives the treatment of interest and the control group does not.
At the end of the trial, outcomes of subjects in each group are determined—the difference in outcomes between groups provides an estimate of the size of the treatment effect.
Reviews of the literature conducted in a way that is designed to minimize bias.
Can be used to assess the effects of health interventions, the accuracy of diagnostic tests, or the prognosis for a particular condition.
Usually involve criteria to determine which studies will be considered, the search strategy used to locate studies, the methods for assessing the quality of the studies, and the process used to synthesize the findings of individual studies.
Particularly useful for busy clinicians who may be unable to access all the relevant trials in an area and may otherwise need to rely upon their own incomplete surveys of relevant trials.
Clinical practice guidelines
Recommendations for management of a particular clinical condition.
Involve compilation of evidence concerning needs and expectations of recipients of care, the accuracy of diagnostic tests, and effects of therapy and prognosis.
Usually necessitates the conduct of one or sometimes several systematic reviews.
May be presented as clinical decision algorithms.
Can provide a useful framework upon which clinicians can build clinical practice.
Numerous physical therapy tests exist that are designed to help the clinician rule out some of the many possible diagnoses. Regardless of which test is chosen, the test must be performed reliably by the clinician in order for the test to be a valuable guide. Reliability describes the extent to which test or measurement is free from error. A test is considered reliable if it produces precise, accurate, and reproducible information.16 Two types of reliability are often described:
- Interrater. Determines whether the same single examiner can repeat the test consistently.
- Intrarater. Determines whether two or more examiners can repeat a test consistently.
Reliability is quantitatively expressed by way of an index of agreement, with the simplest index being the percentage agreement value. The statistical coefficients most commonly used to characterize the reliability of the tests and measures are the intraclass correlation coefficient (ICC) and the kappa statistic (κ), both of which are based on statistical models190:
- The ICC is a reliability coefficient calculated with variance estimates obtained through an analysis of variance (Table 4-26).191 The advantage of the ICC over correlation coefficients is that it does not require the same number of raters per subject, and it can be used for two or more raters or ratings.191
- The κ statistic is a chance-corrected index of agreement that overcomes the problem of chance agreement when used with nominal and ordinal data.192 With nominal data, the κ statistic is applied after the percentage agreement between testers has been determined. However, with higher scale data, it tends to underestimate reliability.193 Theoretically, the κ statistic can be negative if agreement is worse than chance. Practically, in clinical reliability studies, the κ statistic usually varies between 0.00 and 1.00.193 The κ statistic does not differentiate among disagreements; it assumes that all disagreements are of equal significance.193
- Standard error of measurement (SEM). The SEM reflects the reliability of the response when the test is performed many times and is an indication of how much change there might be when the test is repeated.193 If the SEM is small, then the test is stable with minimal variability between tests.193
Table 4-26 Intraclass Correlation Coefficient Benchmark Values ||Download (.pdf)
Table 4-26 Intraclass Correlation Coefficient Benchmark Values
Reasonable agreement for clinical measurements
Test validity is defined as the degree to which a test measures what it purports to be measuring, and how well it correctly classifies individuals with or without a particular disease.17–19 A test is considered to have diagnostic accuracy if it has the ability to discriminate between patients with and without a specific disorder.194
In order to determine if a test is both reliable and valid, the test must be examined in a research study and, preferably, multiple studies.
Validity is directly related to the notion of sensitivity and specificity. The sensitivity and specificity of any physical test to discriminate relevant dysfunction must be appreciated to make meaningful decisions.195 Sensitivity is the ability of the test to pick up what it is testing for, and specificity is the ability of the test to reject what it is not testing for.
- Sensitivity represents the proportion of patients with a disorder who test positive. A test that can correctly identify every person who has the disorder has a sensitivity of 1.0. SnNout is an acronym for when sensitivity of a symptom or sign is high, a negative response rules out the target disorder. Thus, a so-called highly sensitive test helps rule out a disorder. The positive predictive value is the proportion of patients with positive test results who are correctly diagnosed.
- Specificity is the proportion of the study population without the disorder that test negative.196 A test that can correctly identify every person who does not have the target disorder has a specificity of 1.0. SpPin is an acronym for when specificity is extremely high, a positive test result rules in the target disorder. Thus, a so-called highly specific test helps rule in a disorder or condition. The negative predictive value is the proportion of patients with negative test results who are correctly diagnosed.
Interpretation of sensitivity and specificity values is easiest when their values are high.197 A test with a very high sensitivity, but low specificity, and vice versa, is of little value, and the acceptable levels are generally set at between 50% (unacceptable test) and 100% (perfect test), with an arbitrary cutoff at about 80%.196
Once the specificity and sensitivity of the test is established, the predictive value of a positive test versus a negative test can be determined if the prevalence of the disease/dysfunction is known. For example, when the prevalence of the disease increases, a patient with a positive test is more likely to have the disease (a false-negative is less likely). A negative result of a highly sensitive test will probably rule out a common disease, whereas if the disease is rare, the test must be much more specific for it to be clinically useful.
The likelihood ratio (LR) is the index measurement that combines sensitivity and specificity values and can be used to gauge the performance of a diagnostic test, as it indicates how much a given diagnostic test result will lower or raise the pretest probability of the target disorder.97,196
Diagnostic tests are used for the purpose of discovery, confirmation, and exclusion.198 Tests for discovery and exclusion must have high sensitivity for detection, whereas confirmation tests require high specificity.199
Four measures contribute to sensitivity and specificity (Table 4-27):
- True positive. The test indicates that the patient has the disease or the dysfunction, and this is confirmed by the gold standard test.
- False positive. The clinical test indicates that the disease or the dysfunction is present, but this is not confirmed by the gold standard test.
- False negative. The clinical test indicates absence of the disorder, but the gold standard test shows that the disease or dysfunction is present.
- True negative. The clinical and the gold standard test agree that the disease or dysfunction is absent.
Table 4-27 2 × 2 Table ||Download (.pdf)
Table 4-27 2 × 2 Table
a (true +ve)
b (false +ve)
c (false −ve)
d (true −ve)
These values are used to calculate the statistical measures of accuracy, sensitivity, specificity, negative and positive predictive values, and negative and positive LRs, as indicated in Table 4-28. Another way to summarize diagnostic test performance using Table 4-27 is via the diagnostic odds ratio (DOR): DOR = true/false = (a∗d)/(b∗c). The DOR of a test is the ratio of the odds of positivity in disease relative to the odds of positivity in the nondiseased. The value of a DOR ranges from 0 to infinity, with higher values indicating better discriminatory test performance. A value of 1 means that a test does not discriminate between those patients with the disorder and those without.
Table 4-28 Definition and Calculation of Statistical Measures ||Download (.pdf)
Table 4-28 Definition and Calculation of Statistical Measures
The proportion of people who were correctly identified as either having or not having the disease or dysfunction
(TP + TN)/(TP + FP + FN + TN)
The proportion of people who have the disease or dysfunction and who test positive
TP/(TP + FN)
The proportion of people who do not have the disease or dysfunction and who test negative
TN/(FP + TN)
Positive predictive value
The proportion of people who test positive and who have the disease or dysfunction
TP/(TP + FP)
Negative predictive value
The proportion of people who test negative and who do not have the disease or dysfunction
TN/(FN + TN)
How likely a positive test result is in people who have the disease or dysfunction as compared to how likely it is in those who do not have the disease or dysfunction
How likely a negative test result is in people who have the disease or dysfunction as compared to how likely it is in those who do not have the disease or dysfunction
The DOR value rises steeply when sensitivity or specificity becomes near perfect.
The quality assessment of studies of diagnostic accuracy (QUADAS)200 is an evidence-based quality assessment tool currently recommended for use in systematic reviews of diagnostic accuracy studies (DAS). The aim of DAS is to determine how good a particular test is at detecting the target condition. DAS allow the calculation of various statistics that provide an indication of “test performance”—how good the index test is at detecting the target condition. These statistics include sensitivity, specificity, positive and negative predictive values, positive and negative LRs, and diagnostics odds ratios. The QUADAS tool is a list of 14 questions which should each be answered “yes”, “no”, or “unclear” (Table 4-29). A score of 10 or greater of “yes” answers is indicative of a higher quality study, whereas a score of less than 10 “yes” answers suggests a poorly designed study. Throughout this text, the QUADAS score is used (if known) to evaluate the various physical therapy examination tests.
Table 4-29 The QUADAS Toola ||Download (.pdf)
Table 4-29 The QUADAS Toola
Was the spectrum of patients representative of the patients who will receive the test?
Were selection criteria clearly described?
Is the reference standard likely to correctly classify the target condition?
Is the time period between reference standard and index test short enough to be reasonably sure that the target condition did not change between the two tests?
Did the whole sample or a random selection of the sample, receive verification using a reference standard of diagnosis?
Did patients receive the same reference standard regardless of the index test result?
Was the reference standard independent of the index test (i.e., the index test did not form part of the reference standard)?
Was the execution of the index test described in sufficient detail to permit replication of the test?
Was the execution of the reference standard described in sufficient detail to permit its replication?
Were the index test results interpreted without knowledge of the results of the reference standard?
Were the reference standard results interpreted without knowledge of the results of the index test?
Were the same clinical data available when test results were interpreted as would be available when the test is used in practice?
Were uninterpretable/intermediate test results reported?
Were withdrawals from the study explained?