SEARCH RESULTS FOR: Knee-Osteoarthritis

Knee Osteoarthritis

Authors: Jared Topham Knee Osteoarthritis: Pathogenesis and clinical findings Reviewers: Liam Thompson, Raafi Ali Yan Yu*, Kelley DeSouza* * MD at time of publication Primary Causes Secondary Causes Aging ↓ Synovial fluid in joint Gender Females > males Genetics Family history of osteoarthritis Race Black > Caucasian Joint malposition (e.g. valgus or varus) Articular trauma Inflammatory disease or infection (e.g. Rheumatoid or septic arthritis) Obesity and ↑leptin ↑ Chondrocytes, inflammatory mediators, and metalloproteinases Extracellular matrix degradation ↑ Knee joint loading forces Metabolic syndromes (e.g. diabetes mellitus) ↑ Oxidative stress and insulin resistance Low-grade systemic inflammation ↓ Elasticity and ↑ degradation of cartilage ↑ Friction in knee joint with movement ↓ Cartilage along femoral groove and posterior surface of patella Pain, catching, and crepitus (crackling/clicking sound) in the patellofemoral joint Inability/difficulty with kneeling or climbing stairs Abnormal distribution of forces accumulate and stress articular surface ↑ Damage/laxity to soft tissue structures stabilizing knee joint Knee Osteoarthritis (Multifactorial entity characterized by cartilage breakdown, deterioration of connective tissue, and bone deformities) ↓ Cartilage between distal femur and proximal tibia ↓ Joint spaceàto articular dysfunction Radiographic changes See Osteoarthritis (OA): X-Ray Features slide Repeated attempts to repair cartilage and joint disruption Subchondral bone thickening (sclerosis) under joint cartilage and bone spur (osteophyte) formation around joint line Rotational/antero-posterior instability and ↑ external adduction moments during walking Alterations in proteoglycans, fiber arrangement, and collagen composition in soft tissue structures within/around knee joint ↑ Shear forces and medial compartment narrowing erode and pinch soft tissue structures within the knee joint Cruciate ligament degeneration Weakened passive stabilizers of the knee joint Knee giving way and instability (falls) Meniscal tears, if large àprevents knee extension/flexion Locking of the knee Joint line tenderness: Patient points to area of tenderness/pain reproducible upon palpation Anatomical axis of hip, knee, and ankle joints ↑ loading medially Medial > lateral joint line tenderness ↑ Joint friction activating nociceptors in the surrounding anatomical tissues Injury and inflammation ↑ nociceptive responses in soft tissue structures and subchondral bone within knee joint Nociceptive feedback to brain inhibits activity of motor cortex neurons controlling muscles around the knee ↓ Motor output and muscle activation over time ↓ Muscle strength/endurance, lower limb muscle use, functional ability (walking, stairs, etc.) Joint inflammationà accumulation of fluid within joint Stiffness, swelling, redness, and pain Limited joint space reduces range of motion for femur to roll/slide on tibia ↓ Knee flexion and extension Flexion contracture and antalgic gait Reduced weight acceptance of the joint and surrounding muscles/tendons ↓ Mobility and physical dysfunction Muscular atrophy Reduced function of active stabilizers of the knee joint (quadriceps, adductors, hamstrings) Legend: Pathophysiology Mechanism Sign/Symptom/Lab Finding Complications Published July 30, 2023 on www.thecalgaryguide.com