Osteoarthritis, knee

• Knee arthritis
• Knee degenerative joint disease

• 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

• M17.10 Unilateral primary osteoarthritis, unspecified knee
• M17.5 Other unilateral secondary osteoarthritis of knee
• M17.9 Osteoarthritis of knee, unspecified

• 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

Description

• 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

Demographics

• 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

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 or restricted household and work-related activity
• Decreased activity and participation overall

Possible Contributing Causes

• Chronic factors affecting the joint such as obesity, BMD, ...