Objectives: Understanding how surgical procedures influence risk factors associated with patellofemoral instability can help guide surgeons when planning treatments for individual patients. This study sought to understand how patellar tilt is affected in pediatric patients undergoing medial patellofemoral ligament reconstruction (MPFLR) with or without an anterior medializing osteotomy (AMZ).
Utilizing a prospective database of 274 patellofemoral instability patients who underwent MPFLR ± AMZ by one of two orthopedic surgeons at a single institution, those who underwent MPFLR+AMZ were identified. Patients with a history of previous ipsilateral knee surgery, obligate or fixed patellar dislocations, syndromic patients, and no pre-operative MRI were excluded. Pre-operative and post-operative MRIs were used to measure tibial-tuberosity to trochlear groove (TT-TG) distance, while radiographs were used to measure patellar tilt (tilt). Patients were matched based on age at surgery (within 2 years) and pre-operative TT-TG distance (within 2 mm) to a comparison cohort of patients who underwent MPFLR without bony realignment (iMPFLR).
A total of 56 patients were analyzed (28 per group). The mean age of the cohort was 15.5±2.0 years and was similar between both groups (15.9 vs. 15.1 years, p=0.14). When comparing the two cohorts, significant pre- to post-operative improvements in patellar tilt for both MPFLR+AMZ (6.6 degrees, p<0.001) and iMPFLR (3.9 degrees, p=0.013) were noted. While there were no differences in pre-operative patellar tilt (21.2±3.5 vs. 21.1±3.4, p=0.91), post-operatively, MPFLR+AMZ had significantly less patellar tilt than isolated MPFLR (13.2±5.5 vs. 16.5±4.4, p=0.017).
This study found that despite similar pre-operative patellar tilt, post-operative patellar tilt was significantly more improved in patients who underwent MPFLR+AMZ when compared to patients that underwent isolated MPFLR. These findings suggest that surgeons seeking to correct tilt in patients with patellar instability should consider MPFLR with AMZ. Future studies should aim to analyze additional outcomes and patient-reported measures to determine the success of these procedures.