Clark's test (grind test) is used for chondromalacia; what constitutes a positive result?

• A. Painful grinding with knee extension without quadriceps contraction.
• B. Inability to contract the quadriceps without pain during patellar compression.
• C. Painful patellar tracking during knee flexion.
• D. Pain relief with quadriceps contraction during patellar compression.

Answer: (B)

Clark's test evaluates the patellofemoral joint by loading the patella and asking the patient to contract the quadriceps. If the cartilage under the patella is diseased (as in chondromalacia), the added contact stress during quadriceps contraction provokes pain and may even prevent full, pain-free contraction. That pattern—pain that accompanies or blocks the quadriceps contraction when the patella is compressed—is what defines a positive result in this test.

So the best answer is that a positive sign occurs when there is pain that prevents or limits quadriceps contraction during patellar compression. This aligns with the test’s goal of revealing patellofemoral cartilage pathology. The other scenarios don’t reflect the mechanism or execution of the grind (Clark’s) test: grinding or crepitus without a contracted quadriceps isn’t the standard positive finding; patellar tracking during flexion points to a different assessment of patellofemoral mechanics; and pain relief with contraction would contradict the expected provocation pattern of this test.