Standardized pivot shift test improves measurement accuracy

Purpose The variability of the pivot shift test techniques greatly interferes with achieving a quantitative and generally comparable measurement. The purpose of this study was to compare the variation of the quantitative pivot shift measurements with different surgeons' preferred techniques to a standardized technique. The hypothesis was that standardizing the pivot shift test would improve consistency in the quantitative evaluation when compared with surgeon-specific techniques. Methods A whole lower body cadaveric specimen was prepared to have a low-grade pivot shift on one side and high-grade pivot shift on the other side. Twelve expert surgeons performed the pivot shift test using (1) their preferred technique and (2) a standardized technique. Electromagnetic tracking was utilized to measure anterior tibial translation and acceleration of the reduction during the pivot shift test. The variation of the measurement was compared between the surgeons' preferred technique and the standardized technique. Results The anterior tibial translation during pivot shift test was similar between using surgeons' preferred technique (left 24.0 +/- 4.3 mm; right 15.5 +/- 3.8 mm) and using standardized technique (left 25.1 +/- 3.2 mm; right 15.6 +/- 4.0 mm; n.s.). However, the variation in acceleration was significantly smaller with the standardized technique (left 3.0 +/- 1.3 mm/s(2); right 2.5 +/- 0.7 mm/s(2)) compared with the surgeons' preferred technique (left 4.3 +/- 3.3 mm/s(2); right 3.4 +/- 2.3 mm/s(2); both P < 0.01). Conclusion Standardizing the pivot shift test maneuver provides a more consistent quantitative evaluation and may be helpful in designing future multicenter clinical outcome trials.