Describes disorders of the patellofemoral articulation resulting in anterior knee pain

Aetiology

• Encompasses and in many cases is synonymous with various diagnoses including chondromalacia patellae (softening of the hyaline cartilage), adolescent anterior knee pain and lateral patellar compression syndrome
• Common in adolescence, especially in girls
• Exact aetiology unclear - may be due to muscle imbalance, ligamentous laxity and subtle skeletal predisposition (genu valgum, wide hips, femoral neck anteversion, internal rotation)
• There may be softening of the hyaline cartilage of the patella (chondromalacia patellae)
• Some cases have obvious patellar maltracking

Clinical features

• Anterior knee pain, worse going downhill
• Grinding or clicking sensation at the front of the knee and stiffness after prolonged sitting causing 'pseudolocking' where the knee acutely stiffens in a flexed position (in contrast to true locking from a bucket handle meniscal tear)

Investigations

• Clinical diagnosis

Management

• The majority of cases are self‐limiting and the mainstay of treatment is physiotherapy to rebalance the muscles
  • Physiotherapy is aimed at rebalancing the quadriceps muscles (specifically strengthening vastus medialis obliqus, VMO)
• Most younger patients 'grow out' of the condition
• Taping may alleviate symptoms
• Occasionally resistant cases may require surgery to shift the forces on the patella (tibial tubercle transfer) - results can be unpredictable