PREOPERATIVE INDICATORS OF MOTION LOSS AND WEAKNESS FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

Loss of motion and knee extension weakness are recognized as significa nt complications following anterior cruciate ligament (ACL) reconstruc tion. The purpose of this study was to determine 1) what degree of pre operative motion loss represents a risk for postoperative motion probl ems and 2) if preoperative weakness (deficit greater than or equal to 20%) affects return of strength following surgery. Measurements of ran ge oi motion and strength were made on 102 patients (56 men, 46 women; age = 31 +/- 1 years) within 2 weeks prior to ACL reconstruction (pre op) and repeated 6 months following surgery (postop). Thirteen of 40 p atients (33%) lacking greater than or equal to 5 degrees preop, eight of 20 patients (40%) lacking 1-4 degrees preop, and three of 42 (7%) p atients with full extension preop had greater than or equal to 5 degre es loss 6 months postop (p < 0.001). Thirty-two of 39 (82%) patients w ith normal strength preop had weakness 6 months postop. Forty of 51 (7 8%) patients with preop knee extension weakness still had weakness 6 m onths postop. Preop strength was not a good predictor of residual weak ness following ACL reconstruction. The magnitude of the preop extensio n loss appears not to be a risk factor It is the presence or absence o f full extension equal to the contralateral leg that identifies risk f or postop problems regaining extension.