Persistent morbidity after Medial Patellofemoral Ligament Reconstruction — A registry study with an eight-year follow-up on a nationwide cohort from 1996 to 2014

Background To evaluate the trends in treatment of patellar dislocation in the Danish population as a whole from 1996 to 2014 and evaluate the incidence of persistent morbidity after Medial Patellofemoral Ligament Reconstruction (MPFL-R). Methods This epidemiological study was performed by retrospectively searching the Danish National Patients Registry from 1996 to 2014. The study investigated the trends in surgery performed on patients with patellar dislocations and the risk of persistent patellar morbidity (PPM) with an eight-year follow-up. PPM was defined as a new patella-related contact to the healthcare system more than a year after surgery. Results From 1996 to 2014, a total of 1956 MPFL-R were performed in Denmark. In 2014, MPFL-R constituted 75% of all patella-stabilizing surgery and was performed on almost 10% of patients with patellar dislocation. The mean risk of PPM eight years after surgery was 20.9% (18.3–23.4%), and young patients aged 10–17 showed the highest risk of 28.9% (23.7–33.7%). The risk of PPM over time was significantly higher for other patella-stabilizing surgery (33.8%) and patients receiving conservative treatment (29.4%) compared to MPFL-R. Conclusions A rapid rise in the use of MPFL-R was found from 2005 to 2014, constituting 75% of all patella-stabilizing surgery in 2014. The overall risk of persistent patellar morbidity within eight years after MPFL-R was 21%. MPFL-R was found to give a significantly lower risk of PPM over time as compared to other patella-stabilizing surgery and conservative treatment.