Isolated Medial Patellofemoral Ligament Reconstruction in Patellar Instability: Does the Distance Between Tibial Tuberosity-Trochlear Groove Make a Difference?

Abstract

Medial patellofemoral ligament reconstruction (MPFLR) is used in most patellar instability surgeries, there is controversy on adding a tibial tuberosity osteotomy (TTO). To describe the results of isolated MPFLR in patellar instability according to the Tibial Tuberosity-Trochlear Groove distance (TT-TG). Retrospective study of patients with patellar instability with a mature skeleton in one center between 2016 and 2021, using isolated MPFLR. Patients with incomplete clinical and/or radiological records and less than one year follow-up were excluded. Pre-surgical demographic and radiological data (TT-TG, Caton-Deschamps (CD) index, patellar tilt, trochlear dysplasia) were recorded. Patients were divided into three groups according to TT-TG distance (Group 1: < 17mm, Group 2: 17-19, Group 3: ≥ 20mm). A pre and post-surgical Kujala score was performed. Local complications, satisfaction, recurrence and/or reintervention were recorded. Pre-surgical variables between groups, intra and inter-group Kujala differences were compared using Bartlett's test. Consent from the patients and approval from the local ethics committee were obtained. 67 patients met the selection criteria, mean age of 23years, 70% were women. There were no pre surgical, radiological nor follow-up differences between the groups (average 27months). Pre and post-surgical Kujala score, respectively: Group 1: 37-78, Group 2: 37-78, Group 3: 39-79. All groups had a significant improvement (p < 0.05), there were no significant differences in improvement between groups (p > 0.05). There were three patients with a redislocation episode, all in group 1. One patient had a mobilization under anesthesia due to an arthrofibrosis (Group 2). 97% of all cases reported being satisfied. Isolated MPFLR in patellar instability presents a functional improvement, with a low rate of complications and failure, regardless of the pre surgical TT-TG. The online version contains supplementary material available at 10.1007/s43465-023-00906-6.