Abstract
Objectives:
Patellar tendon graft (PTG) use for anterior cruciate ligament reconstruction (ACLR) is associated with donor site morbidity including a loss of flexion range of motion (ROM), persistent quadriceps weakness, anterior knee pain, and a limited return to function. However, the extent of PTG recovery can be overshadowed by the ACLR being performed in the same knee. The purpose of this study was to evaluate the recovery potential of the PTG when taking it from the contralateral knee in ACLR.
Methods:
Between 1990 and 2022, 3991 patients having an ACLR using a contralateral PTG, and a minimum two year follow up were retrospectively reviewed. Patients were excluded with revision surgery or a postoperative patellar tendon rupture. All patients followed a similar postoperative rehabilitation protocol on the graft donor knee including full weight bearing, immediate restoration of preoperative normal range of motion (ROM), and immediate low load/high repetition strength exercises. Postoperative outcome measures included flexion ROM at 2 weeks, isokinetic quadriceps strength compared to preoperative values at 1, 6, 12, and minimum 24 months, single leg hop for distance compared to preoperative values at 4, 6, 12, and minimum 24 months, International Knee Documentation Committee (IKDC) scores at 6, 12, and minimum 24 months, and the rate of return to preinjury level within two years. Repeated measures analysis was used to determine progression over time and Pearson correlation was used to determine the association between quadriceps strength and IKDC scores.
Results:
For the 3991 subjects, mean age was 24.0 years and 58% were male. Mean flexion at 2 weeks postoperative was 145°, which was not significantly different than mean preoperative flexion (145°), p=0.419. Quadriceps strength progressed through time (1 month 57%, 2 months 78%, 6 months 97%, 12 months 109%, minimum 24 months 112%) and the raw strength value at 12 months was higher than the preoperative value (89 Nm vs 84 Nm), p<0.001. All raw values for strength prior to 12 months were significantly lower than preoperative values. Hop for distance progressed through time (4 months 94%, 6 months 100%, 12 months 105%, minimum 24 months 102%) and the raw value at 6 months was similar when compared to the preoperative value (preoperative: 145cm, 6 months: 144cm), p=0.136. All raw values for hop distance prior to 6 months were significantly lower than preoperative values. Subjective scores increased at every time point with the mean score at 6 months being 85, 88 at 12 months, and 89 at a minimum 24 months. One year IKDC scores were statistically significantly correlated to isokinetic quadriceps strength at one year, however the strength of the relationship was weak, r=0.173. Overall, the rate of return to preinjury level of activity was 85%. For those that returned to their preinjury level, there were not any significant differences in quadriceps strength at any time point postoperatively, other than at 1 month postoperative (yes 58% vs no 56%), p=0.030.
Conclusions:
Following isolated PTG harvest for an ACLR, donor knee flexion is quickly restored to normal. Hop testing is back to preoperative normal by 6 months and quadriceps strength exceeded preoperative normal by 12 months postoperative. Return to preinjury activity is not limited by donor knee strength. Clinically, using a PTG from the contralateral knee in ACLR allows the PTG site to adequately recover and in a timely manner.