From the Guidelines
The best clinical screening exam for patellofemoral pain is a combination of knee-targeted exercise therapy and supportive interventions, as recommended by the most recent and highest quality study 1. To perform an effective screening, it's essential to consider the patient's history, focusing on activities that provoke symptoms, such as climbing stairs, squatting, or sitting with knees bent for prolonged periods. The Clarke's test, also known as the patellofemoral grinding test, can be a valuable tool in assessing patellofemoral dysfunction by reproducing the patient's anterior knee pain when the patella is pushed distally and the quadriceps muscle is contracted 1. Other tests, including the patellar apprehension test and the J-sign, can help identify patellofemoral dysfunction by assessing patellar tracking, stability, and pain reproduction. However, it's crucial to prioritize education and adjust interventions according to the patient's needs, as emphasized in the best practice guide for patellofemoral pain 1. Key points to consider when screening for patellofemoral pain include:
- Delivering knee-targeted exercise therapy
- Providing supportive interventions as required
- Underpinning all interventions with education
- Adjusting interventions to reflect the needs of the person By following this approach, clinicians can provide the most effective screening and management for patients with patellofemoral pain, ultimately improving morbidity, mortality, and quality of life.
From the Research
Clinical Screening Exams for Patellofemoral Pain Syndrome
The best clinical screening exam for patellofemoral pain syndrome is a topic of ongoing research, with various studies investigating the diagnostic accuracy of different clinical tests.
- A systematic review of clinical tests for patellofemoral pain syndrome found that the tests with the highest reported diagnostic value were also associated with studies that had the lowest quality scores 2.
- Another study found that the reliability of most physical examination tests alone remains low, but clustering physical examination findings may provide better sensitivities and specificities in diagnosing patellofemoral pain syndrome 3.
- The diagnostic value of five clinical tests, including the vastus medialis coordination test, patellar apprehension test, Waldron's test, Clarke's test, and the eccentric step test, was examined in a study, which found that a positive outcome on either the vastus medialis coordination test, the patellar apprehension test, or the eccentric step test increases the probability of patellofemoral pain syndrome to a small, but sometimes important, degree 4.
Key Findings
- Q angle, patellar tilt, crepitus, strength and functional testing, and physical examination maneuver clustering have been studied as potential predictors of patellofemoral pain syndrome 3.
- Musculoskeletal ultrasound (US) is rapidly gaining popularity as a diagnostic tool for patellofemoral pain syndrome, with decreased vastus medialis obliquus (VMO) volume, asymmetry in gluteus medius thickness, intra-articular effusions, and quadriceps and patellar tendon thicknesses showing value in diagnosing patellofemoral pain syndrome 3.
- A careful history and targeted physical examination are essential in confirming the diagnosis and determining the most appropriate treatment for patellofemoral pain syndrome 5.
- A physical therapy program that employs quadriceps strengthening, manual stretching of the lateral patellar soft-tissue structures, patellar taping, and biofeedback is successful in the majority of cases 5.
Challenges in Diagnosis
- The source of the problem can vary, and must be identified to direct treatment 6.
- Other structures around the knee may present with anterior knee pain and can be mistaken for patellofemoral disorder, which is why the patellofemoral examination should be performed in the context of a complete knee examination 6.
- The findings on physical examination are often subtle and do not consistently correlate with symptoms described 3.