Risk factors and time to recurrent patellar dislocations
The natural history of patellar dislocation is associated with a high rate of recurrence. This large, retrospective cohort study found a cumulative incidence of recurrent ipsilateral patellar dislocation of 36% at 20 years after a first-time lateral patellar dislocation, compared with 5.4% for contralateral patellar dislocation. Trochlear dysplasia, elevated tibial tubercle to trochlear groove (TT-TG) distance, patella alta and age are factors contributing to a decreased time to recurrence.
584 patients sourced from a population-based medical database in Olmsted County, USA were included in the study. Trochlear dysplasia was found to be the strongest risk factor associated with ipsilateral recurrence. Patella alta was also a strong predictor of ipsilateral recurrence and the strongest predictor of subsequent contralateral dislocations.
The mean time to a recurrent ipsilateral dislocation was 43.9 months and 50.9 months for contralateral dislocation. Time to recurrence was significantly decreased in patients with trochlear dysplasia (23.0 months earlier time to recurrence), elevated TT-TG distance (18.5 months), patella alta (16.4 months) and age
Knowing the effect that these factors may play in the timing to recurrence can help to determine the potential indication for surgical intervention to prevent early recurrence.
> From: Christensen et al., Am J Sports Med (2017) (Epub ahead of print). All rights reserved to The Author(s). Click here for the online summary.