Abstract
Aim
This study looks for correlation between pre-operative MRI and intra-operative surgical findings regarding the site of medial patellofemoral ligament (MPFL) rupture in first time patella dislocaters with the aim of confirming the reliability of this modality of imaging.
Methods
A retrospective analysis of all patients who were referred for MRI following patella dislocation was performed. The surgical and MRI findings of those who subsequently underwent MPFL repair were compared to look for any correlation.
Results
41 patients were first time patella dislocators and 38 had MPFL rupture diagnosed on MRI. Of these 19 progressed to surgical intervention and 17 had adequate data available from the notes to permit comparison. All of the MPFLs ruptured at the patella insertion. In 76.5% (13/17) of patients the site of MPFL rupture was correctly identified on MRI scan. Of those that were discordant, 3/4 had the site of rupture identified as the femoral insertion on MRI and on 1/4 had an MRI suggestive of rupture at both the femoral and patella insertions.
Conclusion
MPFL rupture is common in first time dislocations occurring in 93% of this cohort on MRI. There was a predominance for patella insertion rupture in our study which contrasts with the majority of the published literature. By correlating surgical and radiological findings we can conclude that while MRI can accurately diagnose MPFL rupture at the patella insertion it is less accurate in identifying rupture at the femoral insertion.
