Dx and Mx a challenge. Overuse and muscular dysfunction common contributors. Initial management includes quads strengthening. Check footwear and add arch supports if necessary.
Retropatellar / peripatellar pain from changes in patellofemoral joint.
Also referred to as anterior knee pain, runner’s knee, and chondromalacia patellae.
All ages but max younger adults and teenagers (growth spurt).
- Overuse/overload, biomechanical and muscular dysfunction. Theories in bold below
Pes Planus (Pronation) - "Flat feet"
- Combination of eversion, dorsiflexion and abduction of foot leads to compensatory internal rotation of tibia and femur, stressing patellofemoral fxn.
- Treat with medial foot arch support and footwear advice
Pes Cavus (High arched foot, supination)
- Less cushioning for leg when foot strikes ground causes more stress on patellofemoral mechanism especially when running.
- Advise proper (cushioned) footwear with arch support.
- Quads weakness causes instability. Treat with MVO exercises
Key Clinical Features
- Gradual onset anterior knee pain (±bilateral) with exercise - particiularly squatting, hiking, running. Often worse going down hill.
- Rarely after patellar dislocation or direct trauma.
- ±patellar crepitus.
- Pain free at rest but can also occur with prolonged sitting (movie-goer's sign).
- Clinical Dx with Hx and patellar pain on squatting (80%) and patellar margin tenderness (70%).
Consider plain x-rays only if concern about Osteochondritis dessicans or rare neoplasm (red flags or lock / letting down)
- Quadriceps (especially VMO) exercises.
- Physiotherapy supervised hip, hamstring and calf iliotibial band stretching exercises (NNT 3.6).
- Relative rest - initially, e.g. change to swimming in runners.
- Patient education (NNT 5 at 24 months)
- Movie-goers should start walking regularly.
- Ice - particularly immediately after running (for 10 - 20 minutes)
- No strong evidence for (or against) NSAIDs
- Do not use knee splint / braces (unless physiotherapist requests)
- Taping the knee - no strong evidence either way - physiotherapist can educate patient how to tape their knee for trial
- Quality footwear - Arch support usually helps (NNT 4).
- Surgery only for true chondromalacia (fraying retropatellar cartilage)
- Spontaneous resolution. Masterful inactivity (by physician) may be best option in growing adolescents.
Most patients do well with conservative management.