Chondromalacia Patella: Causes, Grading & Physiotherapy Treatment for Kneecap Pain

Chondromalacia Patella: The Complete Physiotherapy Guide

Chondromalacia patella (CMP) — also classified under the broader term Patellofemoral Pain Syndrome (PFPS) — is one of the most common causes of anterior knee pain, particularly in young active people, women, and runners. The articular cartilage on the posterior surface of the patella undergoes softening and structural damage from abnormal mechanical loading.

Grading of Cartilage Damage (Outerbridge Classification)

Grade I: Softening and swelling of the cartilage. No fissuring. Conservative physiotherapy highly effective.

Grade II: Partial thickness fissures < 1.5 cm diameter. Still responds well to physiotherapy.

Grade III: Full thickness fissures > 1.5 cm. More complex management, but physiotherapy remains first-line.

Grade IV: Erosion down to bone. Patellofemoral osteoarthritis. Surgical intervention may be considered, but physiotherapy still essential pre- and post-operatively.

Why the Patella Hurts: The Biomechanical Story

The patella tracks in the femoral trochlear groove during knee flexion and extension. Abnormal tracking — where the patella shifts laterally (outward) — creates focal high-pressure contact zones on the cartilage, causing pain and eventual damage.

Causes of abnormal patellar tracking:

• VMO weakness: The Vastus Medialis Oblique (inner quadriceps) provides medial patellar traction. Weak VMO → lateral drift
• Hip abductor weakness: Weak gluteus medius → femur internally rotates → increases Q-angle → lateral patellar tilt
• Foot pronation: Overpronation internally rotates the tibia → compounds the lateral vector
• Tight lateral retinaculum: The lateral soft tissue tether holds the patella laterally

Physiotherapy Treatment Protocol

Phase 1: Pain Control (Week 1–3)

• Activity modification: Avoid deep squatting, stairs, prolonged sitting with flexed knee
• Patellar taping (McConnell technique): Tape pulls the patella medially, immediately improving pain by correcting tracking during daily activities and exercise
• Knee bracing: Patellar stabilizing brace provides continuous medial glide assistance
• Ice: 15–20 minutes after activity
• NSAIDs (if prescribed by doctor): Short-term for acute inflammation

Phase 2: VMO and Hip Strengthening (Week 3–8)

Priority 1: VMO Activation

• Terminal Knee Extension: Resistance band behind knee. Extend the last 20° of knee straightening, squeeze VMO hard, hold 2 seconds. 20 reps × 3 sets.
• Quad sets: Knee straight, press back of knee into floor, squeeze VMO. 20 reps × 3 sets.
• Short-arc quads: Supported at 40° flexion, extend to full. VMO is most active in the last 30° of extension.

Priority 2: Hip Abductor Strengthening

• Side-lying hip abduction, clamshells, lateral band walks — 15 reps × 3 sets

Priority 3: Patellar Mobilization Manual medial and inferior patellar glides to stretch the lateral retinaculum. Performed by physiotherapist. Reduces lateral tilt and immediately reduces pain in many patients.

Phase 3: Return to Loading (Week 8–16)

Progressive reintroduction of loaded activities:

• Mini-squats (0–45°) → progressing to 0–60°, then 0–90°
• Step-ups (low → higher step)
• Cycling (low resistance, high seat height initially)
• Running programme (gradual progressive return)
• Sport-specific training