The incidence and epidemiology of patellar fractures following medial patellofemoral ligament reconstruction: a systematic review and meta-analysis

Abstract

Patellar instability can arise from a traumatic event with anatomical predisposing factors increasing the risk of dislocation. Medial patellofemoral ligament reconstruction (MPFLR) is commonly performed to treat patellar instability. The aim of this systematic review was to determine the incidence of and risk factors for patellar fractures after MPFLR. The protocol for this review was registered on PROSPERO with registration number CRD420251066107. The PRISMA 2020 checklist was followed. Electronic databases and conference proceedings were searched to the 15th of May 2025. Studies were eligible if they reported incidence of patellar fractures after MPFLR. A random-effects meta-analysis was performed. Included studies were appraised using tools respective of study design. A total of 4,972 records were screened in the initial search. A total of 110 studies satisfied the inclusion criteria, evaluating 115,496 patients. The evidence was moderate to low in quality. The incidence of patellar fracture ranged from 0 to 9.50%, with a pooled incidence of 1.17% (95% confidence interval [CI] 0.76- 1.68%). There was no difference in incidence of patellar fractures between patients who did and did not undergo bone tunnel fixation (0.94%, 95% CI 0.69–1.24 vs. 1.00%, 95% CI 0.15–2.44%, respectively). There was no difference in fracture incidence between patients who underwent concomitant procedures (1.26%, 95% CI 0.51–2.32) and those who underwent MPFLR alone (0.53%, 95% CI 0.13–1.16%). Patellar fractures are a known complication of MPFLR, with a higher incidence observed in patients undergoing this procedure compared to the baseline population risk. Current evidence suggests its incidence is not affected by tunnel location or the performance of concomitant procedures, though further prospective studies are required to corroborate this. Appropriate post-operative follow-up is required to monitor the occurrence of patellar fractures during the post-operative period.