Comparison of Early Strength Return Following Anterior Cruciate Ligament Reconstruction Comparing Patellar Tendon Grafts and Quadriceps Tendon Grafts

Background: Anterior Cruciate Ligament Reconstruction(ACLR) utilizing a patellar tendon graft (PTG) has served as the gold standard for high demand patients for several decades. Recent reports suggest failure rates are higher in younger and high demand patient groups. In addition, morbidity associated with PTGs remains significant and can linger as athletes return to sports specific activities following surgery. As a result, there has been increased interest in using quadriceps tendon grafts(QTG) for ACLR in high risk patients. Graft volume is significantly greater than a PTG and postoperative tendon symptoms appear to be less frequent. However, early rehabilitation following ACLR appears to be more diQicult when utilizing a QTG and strength gains appear to lag behind patients utilizing a PTG. This is particularly true of the first few weeks following surgery. Very little data is available to compare early strength loss and subsequent gains between ipsilateral PTG and QTG reconstructions. These strength deficits may influence the time needed to return to activities of daily living(ADLs) and/or sport specific activities. Purpose: To determine rates of early strength return following ACLR comparing patients receiving an ipsilateral PTG and those receiving an ipsilateral QTG. Methods: A total of 114 consecutive patients who underwent ACLR between March 2022 and December 2023 were retrospectively reviewed. Of these, 77 patients utilized an ipsilateral PTG and 37 an ipsilateral QTG. Grafts harvested from the quadriceps tendon included a patellar based bone plug. An accelerated postoperative rehabilitation protocol was utilized for all patients. Isometric and Isokinetic strength data was collected during 5 week, 10 week, 4 month, 6 month, and 1 year postoperative visits. Comparison was made between the operative and nonoperative extremity for both quadriceps and hamstring strength. Results: Isometric and Isokinetic strength test were obtained on 114 Patients. Ipsilateral PTGs were utilized in 77 patients (37 male, 40 female) average age 29.4+/−9.6. Ipsilateral QTGs were utilized in 37 patients(23 male, 14 female) average age 18.4+/−5.0. Initial testing at 5 weeks following surgery revealed PTG patients regaining an average of 44.0%+/−14.9% and 46.8%+/−13.5% for isometric and isokinetic quadriceps strength testing, respectively. Ipsilateral QTG patients averaged 32.3%+/−12.7% and 33.8%+/−12.5% for isometric and isokinetic testing, respectively. Strength testing at the 10 week visit revealed PTG patients averaging 61.1%+/−13.6% and 60.8%+/−17.1% while QTGs averaged 55.3%+/−12.4 and 55.8%+/−11.5% for isometric and isokinetic testing, respectively. Four month testing revealed no significant difference in quadriceps strength values between study groups. PTG and QTG groups averaged approximately 70% for both isometric and isokinetic testing. Six month and 1 year strength test again revealed similar strength values for both study groups. At 6 month follow-up the PTG and QTG patients averaged approximately 70% strength return. At 1 year visits PTG values averaged 95.8%+/−13.3% and 80.9%+/−17.0% while QTG testing averaged 92.8%+/−11.1% and 86.8%+/−5.9% for isometric and isokinetic testing, respectively. When patients were stratified based on gender, both men and woman demonstrated similar results. Patients in the QTG group had greater strength deficits than the PTG patients prior to 4 month testing for both genders. Results at 6 month and 1 year revealed no significant difference for both male and female patients. Hamstring strength was unchanged throughout the data collection period for both groups. Conclusion: Comparison of strength data in ipsilateral PTG and QTG procedures reveal more dramatic quadriceps deficits in patients undergoing ACLR with QTGs during the early time frame of postoperative rehabilitation. This increased strength deficit in the QTG group most likely explains the observed difficulty this group has in returning to early ADLs. Four month testing reveals similar strength return in both study groups. This catch up in the QTG patients allows for a similar time frame for returning to activities such as jogging or controlled proprioception exercises. We generally require 75-80% quadriceps strength return prior to this progression in therapy. Both study groups realized this milestone at similar time following ACLR surgery. Isometric results at 1 year postoperative follow-up demonstrated over 90% strength return in both PTG and QTG patients. These values allow for both patient groups to return to full unrestricted activities between 9 and 12 months following surgery.