MRI-associated classification to evaluate the outcome after autologous reconstruction of the medial patellofemoral ligament: a preliminary study

Purpose Purpose of this study was to establish and validate an MRI-associated classification to graduate postoperative results of MPFL reconstructions. Methods 30 autologous MPFL reconstructions of 28 patients were evaluated by two independent raters using MRI. All grafts were assigned to a novel graduation system respecting the graft’s anchoring insertions, its MRI signal appearance, continuity and tension and the differentiation relating to the surrounding soft tissue. Results All grafts could reliably be assigned to one of the subgroups by both raters. 86.6 % of the grafts could be classified A1 or B1, reflecting a correct positioning and a low to intermediate signal intensity. Only one graft had to be classified C3 (malpositioned, elongated). Conclusion We were able to establish and validate an MRI-associated classification to graduate the postoperative outcome after MPFL reconstructions. Foresighted, the presented classification might support further decision making in case of unsatisfying postoperative results.