The acute pivot shift: Clinical correlation

Abstract

The pivot shift test and its various modifications has been well described for evaluation of chronic antero lateral rotatory insufficiency of the knee. Fifty knees with acute traumatic hemarthrosis were examined un der general anesthesia to assess the reliability of the pivot shift in the acute injury. The pivot shift test as described by Galway and Maclntosh was employed. No patients with a history of previous knee injuries were included. Arthrotomy or arthroscopy was per formed following the examination in all cases. There were 38 knees with positive shifts, 35 with complete anterior cruciate tears, and 3 with significant partial tears or attenuation of the ligament. The 12 knees with negative shift demonstrated five normal anterior cru ciates, five partial tears and two complete tears of the anterior cruciate. Both of the complete tears were associated with complete medial collateral ligament tears and were clinically apparent by drawer and Lach man tests. A positive pivot shift in this study was very accurate for significant anterior cruciate tears. A nega tive pivot shift ruled out complete anterior cruciate ligament tears but did not preclude the presence of a partial tear. Partial tears associated with a negative pivot shift retained ligament competence. We conclude that: (1) the pivot shift is a direct test of cruciate competence; (2) the pivot shift is present acutely in a very high percentage of cases and does not necessarily develop over time; (3) the pivot shift exam performed under general anesthesia is a very reliable test for significant tears of the anterior cruciate; and (4) the arthroscope remains a useful tool in the evaluation of acute traumatic hemarthrosis, but is not always necessary in establishing competence of the anterior cruciate ligament.