Knee flexor function 2 years after anterior cruciate ligament reconstruction with semitendinosus-gracilis autografts

Purpose: This retrospective study evaluated the knee flexor function of 20 patients at 25.8 +/- 5 months after anterior cruciate ligament reconstruction with use of a semitendinosus-gracilis (STG) autograft. Methods: Clinical examinations included instrumented isometric testing, conventional and prone isokinetic testing, hop testing, knee arthrometry, modified visual analog scale leg sensation evaluation, and International Knee Documentation Committee (IKDC) Subjective Knee and Current Health Evaluations. Paired t tests were used to evaluate side-to-side differences, and multiple regression analysis related these findings to knee function (P < .05). Results: Involved side active knee flexion was decreased by 8.2 degrees +/- 5 degrees. Involved side isokinetic knee flexor work was decreased by 76.7 +/- 118 J at 60 degrees/sec during conventional testing and was decreased by 94.4 +/- 107 J and 86.3 +/- 115 J at 60 degrees/sec and 180 degrees/sec, respectively, during prone testing. Isometric testing at 90 degrees and 120 degrees flexion in internal and neutral tibial rotation, respectively, revealed decreased involved side knee flexor torque >= 13.2 +/- 12 Nm. Sensation scores revealed a mean 24% difference from the uninvolved side (range, 0% to 80%). Multiple regression revealed that instrumented isometric testing at 90 degrees knee flexion with neutral fibial rotation and the role physical score predicted 62% (R-2 = .62) of involved side forward hop capability (P < .0001). Self-reported activity level and isokinetic work (60 degrees/sec) predicted 69% (R-2 = .69) of involved side lateral hop capability (P < .0001). Sensation, role physical score, and prone isokinetic peak torque (180 degrees/sec) predicted 80% (R-2 = .80) of involved side medial hop capability (P < .0001). Conclusions: Two years after surgery, functionally significant knee flexor strength deficits remain. Prone isokinetic knee flexor work at 60 degrees/sec, isometric knee flexor torque at 90 degrees flexion-neutral tibial rotation, and sensation score were related to patient function 2 years after anterior cruciate ligament reconstruction with an STG autograft. Level of Evidence: Level IV, therapeutic case series.