Outcomes comparing synthetic and autologous grafts for the reconstruction of the medial patellofemoral ligament. Results of the Syn-VAR prospective randomised trial.

Abstract

Medial patellofemoral ligament (MPFL) reconstruction is a useful technique for managing patellar instability. Various grafts choices and outcomes are reported, however, no randomised control trial directly comparing autograft to synthetic grafts exist. This paper is the result of a previously published clinical trial protocol directly comparing graft choices. An ISRCTN registered, non-inferiority, prospective randomised-control trial was conducted. Full trial protocol was previously published. Patient demographics, radiological parameters and clinical outcomes were collated. A sample size was estimated based on previously published studies. A 1:1 recruitment with block randomisation was performed. Validated knee outcome scores are reported. Data was blinded for all analyses based on an intention to treat design. A p < 0.05 was considered statistically significant. A total of 20 patients in each arm were prospectively followed for a minimum of 2 years post surgery. Follow up retained an adequately powered study based on the protocol. Mean age of 19.1 ± 3.6 years. Tegner, Lysholm, Kujala, International Knee Documentation Committee (IKDC) and Banff Patellar Instability Index (BPII) all improved post operatively, mainly at 1 year. Recovery trajectory showed 2/3 improve at 1 year, and further improvement occurs in 1/3 of patients out to 2 years irrespective of graft choice. Outcome scores were not significantly different between graft groups at any time points. Functional strength assessment showed significantly higher strength with autologous reconstruction at 1 and 2 years post op. No significant difference in outcomes were observed between autologous hamstring and synthetic reconstruction of the MPFL. Further large scale Randomised Control Trials (RCTs) are required comparing autograft and synthetic alternatives.