Poster 226: Autograft versus Allograft for Medial Patellofemoral Ligament Reconstruction: A Systematic Review.

Objectives: Patients with recurrent lateral patellar dislocations are often treated with reconstruction of the medial patellofemoral ligament (MPFL). The purpose of this study was to perform a systematic review to evaluate clinical outcomes and the risk of recurrent patellar dislocation following medial patellofemoral ligament reconstruction (MPFLR) with autograft versus allograft. Methods: A systematic review was performed by searching PubMed, the Cochrane Library, and Embase to identify studies comparing outcomes of MPFLR with autograft versus allograft. The search phrase used was: medial patellofemoral ligament reconstruction autograft allograft. The inclusion criteria were full-text studies that directly compared clinical outcomes and/or risk of recurrent patellar instability events between patients undergoing MPFLR with autograft versus allograft. A quality assessment was performed using the Modified Coleman Methodology Score (MCMS). Risk of bias was performed using the ROBINS-I and the Cochrane Collaboration's risk of bias tools. Results: Seven studies (one level II, three level III, three level IV) were identified that met inclusion criteria, including a total of 150 patients who underwent MPFLR with autograft and 193 with allograft (Figure 1, Table 1). All studies showed a moderate risk of bias due to confounding, and five studies showed a moderate risk of bias for using non-blinded but identical postoperative protocols. All six studies showed serious risk of bias for using physicians not blinded to the treatment group (Figure 2). One study found a significantly higher failure rate among autograft patients, and another study found a trend toward a significantly higher failure rate among autograft patients (Table 2). One study demonstrated no significant difference between tibial tubercle-trochlear groove distance (measured on magnetic resonance imaging) in failed versus successful grafts. One study found that patellar tilt angle improved significantly from preoperatively to postoperatively (p<0.001), but there was no difference between the groups. Kujala scores significantly improved for both autograft and allograft patients across studies. Two studies found significant differences in postoperative Kujala scores between the two groups, one of which found better scores in allograft patients (p=0.0032) and another in which scores were better in autograft patients (p=0.02). Conclusions: This is the first systematic review limited to comparative studies comparing autograft versus allograft for MPFL reconstruction. Patients undergoing MPFLR with either autograft or allograft can expect to experience improvement in clinical outcomes. Graft failure was more frequently observed in autograft patients. Subjective outcomes improved to a similar degree in both groups. Allograft may be a better option for MPFLR due to lower failure rate. Figure 1. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram. Figure 2. ROBINS-I risk of bias Table 1. Study characteristics Table 2. Failure rates. [ABSTRACT FROM AUTHOR]