An evaluation of the clinical tests and outcome measures used to assess patellar instability.

A literature review was undertaken to determine which clinical tests and outcome measures have been described to diagnose and evaluate patellar instability, and to assess the literature examining the sensitivity and specificity of these diagnostic tests, or the reliability, validity and responsiveness of the outcome measures identified. An electronic search was undertaken using standard databases as well as a hand search of specialist journals, reference lists and local medical libraries. All English language publications describing and/or evaluating diagnostic tests and outcome measures for patellar instability patients were included. On review, 104 papers and 64 textbooks were included. Eighteen diagnostic tests and 10 outcome measures were identified. Of these only five diagnostic tests (Bassett's sign; apprehension test; gravity subluxation test; clinical assessment of the tibial tubercle to trochlear groove value; Q-angle) and seven outcome measures (modified International Knee Documentation Committee knee ligament standard evaluation form; Kujala anterior knee pain scale; Fulkerson knee instability scale; Lysholm knee scoring scale; Tegner activity level scale; Short Form-36; Musculoskeletal Function Assessment injury and arthritis survey) had been assessed for accuracy in five studies. The sensitivity, specificity, reliability or validity, of these tests remains unclear for this patient population. Further work is needed to assess the appropriateness of the identified tests and outcomes for patellar instability cohorts.