Anterior Knee Pain

Definition/diagnostic criteria Anterior knee pain (AKP), often termed patellofemoral pain syndrome (PFPS), is characterised by pain around or behind the patella, exacerbated by activities such as squatting, stair climbing or prolonged sitting. Some authorities recognise PFPS as a clinical syndrome without specific structural changes or a single pathoanatomical cause. Diagnostic criteria focus on excluding other causes of knee pain.

Epidemiology AKP is common, particularly in adolescents and young adults. It accounts for 25-40% of all knee problems in sports medicine clinics. There’s a slight female predominance, possibly due to anatomical and hormonal differences.

Diagnosis
Clinical features: Diagnosis is primarily clinical. Key features include:

• Peripatellar or retropatellar pain, often described as aching or discomfort.
• Pain aggravated by activities loading the patellofemoral joint under flexion, like climbing stairs, squatting or prolonged sitting (the ‘movie-goer’s sign’).
• Crepitus or a sensation of grinding may be noted on knee extension.
• Tenderness on palpation of the patella, without significant effusion or ligamentous laxity.

Investigations: Routine imaging is not recommended unless there is suspicion of other pathology. If imaging is indicated:

• X-rays can rule out fractures or osteoarthritis.
• MRI may be used if there’s suspicion of soft tissue pathology but is not routinely indicated.

Treatment Management is typically conservative.

• Education and self-management: Advice on activity modification and pain management.
• Exercise therapy: Key component, focusing on strengthening the quadriceps, particularly the vastus medialis oblique. Hip and core strengthening exercises are also beneficial.
• Pharmacotherapy: Pain relief with paracetamol or topical NSAIDs. Oral NSAIDs can be considered but with caution regarding gastrointestinal, renal and cardiovascular risks.
• Foot orthoses: For individuals with foot biomechanical issues.
• Patellar taping or bracing: Can provide short-term pain relief.
• Referral to physiotherapy: For tailored exercise regimens and further management.

Prognosis The natural course is variable. While many patients experience significant improvement with conservative treatment, symptoms can persist for years in some cases. Factors suggesting a poorer prognosis include higher pain levels, longer duration of symptoms before presentation and lower levels of physical activity. Long-term sequelae include potential development of patellofemoral osteoarthritis.