Skip to Main Content

Condition/Disorder Synonyms

  • Knee arthritis

  • Knee degenerative joint disease

ICD-9-CM Code

  • 715 Osteoarthrosis and allied disorders

  • 715.16 Osteoarthrosis localized primary involving lower leg

  • 715.26 Osteoarthrosis localized secondary involving lower leg

  • 715.36 Osteoarthrosis localized not specified whether primary or secondary involving lower leg

  • 715.9 Osteoarthrosis, unspecified whether generalized or localized

  • 715.95 Osteoarthrosis, unspecified whether generalized or localized involving pelvic region and thigh

ICD-10-CM Code

  • M17.10 Unilateral primary osteoarthritis, unspecified knee

  • M17.5 Other unilateral secondary osteoarthritis of knee

  • M17.9 Osteoarthritis of knee, unspecified

Preferred Practice Patterns

  • 4D: Impaired joint mobility, motor function, muscle performance, and range of motion associated with connective tissue dysfunction1

  • 4F: Impaired Joint Mobility, Motor Function, Muscle Performance, Range of Motion, and Reflex Integrity Associated With Spinal Disorders2

  • 4H: Impaired Joint Mobility, Motor Function, Muscle Performance, and Range of Motion Associated With Joint Arthroplasty3

  • 4I: Impaired Joint Mobility, Motor Function, Muscle Performance, and Range of Motion Associated With Bony or Soft Tissue Surgery4

Key Features


  • Most common form of arthritis

  • Degenerative

  • Commonly affects hip and knee joints, weight-bearing joints

  • Can also affect spinal facet joints

  • Associated with increasing age, obesity, female sex and race/ethnicity

  • Associated with abnormal loading of the joints

  • Characterized by joint pain

  • Arthrosis

  • Osteoarthrosis

  • Polyarthrosis

  • Degenerative joint disease

Essentials of Diagnosis

  • Radiography is standard method for diagnosis

  • Kellgren-Lawrence (KL) Grade ≥ 2 (definite radiographic OA)5

  • Osteophytes, joint-space narrowing, sclerosis

  • Cartilage lesions, bone marrow lesions, synovitis, effusion, and subchondral bone attrition/sclerosis

  • Erosion of articular cartilage

  • Synovial hyperplasia

  • Fibrosis

  • Inflammatory cell infiltration

    • With or without OA symptoms

  • Conventional radiograph is most commonly used tool in OA

  • Diagnosis based on careful history and physical examination, imaging studies, laboratory examination, exclusion of other possible diseases

General Considerations

  • Low bone mineral density (BMD)

  • Repetitive joint use or loading

  • Joint alignment

  • Leg-length discrepancy or inequality (LLD)

  • Bone or joint morphology

  • Calcification (of the knee meniscus)

  • Bone formation, cyst formation

  • Thickening of subchondral bone plate, osteosclerosis

  • Overall joint dysfunction

  • Joint swelling and inflammation (in certain cases, severe cases)

  • Joint pain

  • Morning stiffness

  • Long-term disease

  • Secondary problems

    • Muscle atrophy and weakness

    • Bony protrusion/prominence

    • Joint deformity

    • Difficulty walking

    • Difficulty with ADLs


  • Aging (onset middle- to old-age)

  • Women more commonly affected than men

  • African American and Caucasian more commonly affected

  • May affect approximately 12% of the population (U.S. and other developed countries)6

Clinical Findings

Signs and Symptoms

  • Joint pain

  • Aching joint

  • Joint stiffness

  • Muscle weakness

  • Muscle atrophy

  • Crepitus

  • Bony enlargement

  • Limited joint range of motion (ROM)

  • Joint line tenderness

  • Joint deformity in severe cases

  • Activity limitation

Functional Implications

  • Limited mobility

  • Limited ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.