Retrospective Outcomes of Augmented Medial Patellofemoral Ligament Repair with a Reinforced Bioinductive Implant: A Short-Term Follow-up Analysis

Background Patellar instability is commonly associated with disruption of the medial patellofemoral ligament (MPFL). Although MPFL reconstruction (MPFLR) is the current standard of care, complication rates remain notable, particularly in young and high-risk patients. Reinforced bioinductive implants (RBI) have recently emerged as a biologically supportive alternative. Augmented MPFL repair (AMPFLr) using an RBI aims to combine anatomic reconstruction principles with biologic repair augmentation. The purpose of this study is to retrospectively evaluate patient reported outcomes and re-dislocation rates after undergoing AMPFLr using an RBI for patella instability. It is hypothesized that patients who underwent this procedure demonstrate clinical improvement over baseline in patient reported outcomes metrics (PROMs) and range of motion. A secondary hypothesis is AMPFLr would be non-inferior compared to historical data at early time points. Methods A retrospective review was performed for all patients undergoing AMPFLr between May 2021 and September 2024 at a single institution. Inclusion criteria were primary MPFL surgery, age ≥14 years, preoperative MRI confirming MPFL tear, RBI augmentation, and ≥1-year follow-up. Exclusion criteria included allograft/autograft use, inadequate imaging, derotational osteotomies, and concomitant ACL reconstruction. Outcomes included range of motion (ROM), visual analog scale (VAS) pain scores, and BANFF Patella Instability Instrument (BPII2.0) scores collected preoperatively and at 6 and 12 months. Complications and reoperations were recorded. Paired t-tests compared postoperative values to baseline (α = 0.05). Results Forty-seven patients met inclusion criteria (mean age, 23.9 ± 8.5 years; 61.7% female) with a mean clinical follow-up of 12.7 ± 2.6 months. Three patients (6.4%) underwent reoperation: two for arthrofibrosis requiring manipulation under anesthesia and one for tibial tubercle osteotomy hardware failure after trauma. 1 patient suffered complete re-dislocation, 3 patients (6%) reported subjective instability during pivoting. Significant improvement was observed across all outcome measures. VAS pain decreased from 4.4 ± 1.4 to 0.5 ± 0.8 at 12 months (p < 0.001). BPII2.0 scores improved from 36.7 ± 7.8 to 73.9 ± 5.3 at 12 months (p < 0.001). Flexion increased from 106.8° ± 17.2° to 128.6° ± 5.0° (p < 0.001), and extension normalized by 12 months (p = 0.004). Conclusion AMPFLr with RBI augmentation resulted in significant improvements in pain, function, and knee ROM within 12 months, with no cases of recurrent dislocation and a low reoperation rate. PROM improvements were comparable to historically reported MPFL reconstruction outcomes, supporting the non-inferiority of AMPFLr at early follow-up. These findings suggest that AMPFLr is a safe and effective option for treating patellar instability, though longer-term and comparative studies are needed to determine durability and optimize indications. Level of Evidence Level IV, retrospective case series.