Extraarticular transposition of the patellar tendon for anterolateral instability of the knee. Poor results in 52 patients after 5-14-year follow-up.

Several extraarticular surgical procedures have been proposed to eliminate the anterolateral rotatory instability of an anterior cruciate-deficient knee. We examined the outcome in 52 patients with an extraarticular transposition of the lateral third of the patellar tendon to the lateral femoral condyle. The mean follow-up time was 9 years. The evaluation was based on the patients' subjective assessment, the Tegner activity level score, range of motion, Lysholm functional score, assessment of knee instability using manual testing as well as arthrometer measurements, and weight-bearing radiographs. At follow-up, 37 patients stated that they had good-to-excellent knee function. The mean Tegner score dropped from a preinjury level of 7 to 5.43 patients had a good-to-excellent Lysholm score. 20 patients had a positive Lachman sign of grade 2 or 3, and 23 patients had a side-to-side difference of more than 3 mm as measured by an arthrometer. 17 had a positive pivot shift sign. 12 patients had meniscal resections performed after the primary operation, and 27 had radiographic evidence of arthrosis. Although the outcome of this technique is equivalent to or better than results reported for other extraarticular procedures, the recurrence rate of symptomatic instability and the deterioration of subjective knee function are too high.