Knee strength deficits following anterior cruciate ligament reconstruction differ between quadriceps and hamstring tendon autografts.

Abstract

To compare patient reported outcomes and functional knee recovery following anterior cruciate ligament (ACL) reconstruction using either a quadriceps tendon (QT) or hamstring tendon (HT) autograft. Thirty-five QT patients (age 20; range 15-34years) participated in this study and were matched for gender, age and pre-injury activity level to 70 HT (age 20; range 15-32years) patients. The following assessments were performed at 6 and 12months post-operatively; standardized patient-reported outcome measures (IKDC, KOOS-QOL, ACL-RSI, Marx activity, anterior knee pain), knee range of motion (passive and active), anterior knee laxity, hop tests (single and triple crossover hop for distance), and isokinetic strength of the knee extensors and flexors. All dependent variables were analysed using a two-way mixed ANOVA model, with within (Time; 6 and 12months) and between-subject (Graft; QT and HT) factors. Patient reported outcome measures and hop performance improved between 6 and 12months (p < 0.001), however no significant differences in either patient-reported outcomes or hop performance were found between the two grafts. Isokinetic strength testing showed both groups improved their peak knee extensor strength in the operated limb between 6 and 12months (p < 0.001), but the QT group had significantly lower knee extensor strength symmetry at both time points compared to HT at 60deg/s (p < 0.001) and 180deg/s (p < 0.01). In contrast, the QT group had significantly greater knee flexor strength symmetry at both time points compared to HT at 60deg/s (p < 0.01) and 180deg/s (p = 0.01), but knee flexor strength limb symmetry did not significantly improve over time in either group. Recovery of knee function following either QT or HT ACL reconstruction continues between 6 and 12months after surgery. However, knee extensor strength deficits in the QT group and knee flexor strength deficits in the HT persisted at 12months. This may have implications for decisions regarding return to sport. III.