Execution:
- Patient is in supine-lying with the lower leg hanging over the edge of the bench
- Tthe patient’s leg is in full extension and the examiner uses the thumb of one hand to translate the patella laterally
- The examiner moves the leg into 90° of flexion and notes any signs of apprehension orally expressed by the patient or quadriceps contraction in an attempt to stop flexion and/or to dynamically reposition the patella
- The patient’s leg is brought back to full extension while the lateral translation of the patella is maintained
- The examiner now medially translates the patella as far as possible using the index finger
- The patient’s knee is flexed to 90° and elimination of apprehension and quadriceps contraction is noted
Positive Outcome: Both eliciting and elimination of apprehension have to be positive
| Study | Reliability | Sn | Sp | LR+ | LR- |
| Ahmad et al. (2009) | NA | 100 | 88.4 | 8.62 | 0 |
| Comment: Ahmad and colleagues state the following: In full knee extension, the patella is in its most unstable position and soft tissues and alignment are most responsible for the patella’s stability. As flexion begins, the patella must engage the trochlea and then stability is shared by the soft tissues, overall alignment, and the bone geometry of the trochlea and patella. For a knee without patellar instability, as the knee flexes, the patella is guided into the trochlea by the MPFL and other medial soft tissue stabilizers. The patella subluxates most easily at 20° of knee flexion, and the MPFL seems to resist lateral patellar subluxation greatest when the knee is toward full extension. For patients with symptomatic instability, while the knee is flexing combined with an eccentric quadriceps force, the patella engages the trochlea in a lateral position and then dislocates or subluxates as the knee continues to flex. For the patient with patellar instability who is being evaluated with the MPAT, as the knee flexes during the first part of the test, the patella engages the trochlea in a lateral position and mimics a patellar dislocation episode, therefore reproducing the symptoms associated with a dislocation. The MPAT also actively assesses the MPFL since the MPFL is responsible for guiding the patella properly into the trochlea as the knee moves from full extension into flexion.In the second part of the test, with medial force on the patella as the knee is flexed, the symptoms of impending dislocation are eliminated because the patella engages the trochlea in a normal fashion. The manual translation of the patella reproduces the function of the deficient and/or incompetent MPFL. The test is a combination of apprehension in part 1 and the reduction of the apprehension in part 2. This dynamic, provocative test is similar in concept to the pivot-shift test for ACL insufficiency in the knee, the release test for anterior shoulder instability, and the moving valgus stress test for valgus instability of the elbow | |||||
