Primary patellar dislocations without surgical stabilization or recurrence: how well are these patients really doing?

Magnussen RA, Verlage M, Stock E, Zurek L, Flanigan DC, Tompkins M, Agel J, Arendt EA. [PubMed: ]

This is the editor's interpretation of a paper published in the orthopaedic literature in 2017 - our attempt to make relevant medical articles accessible to lay readers. If you wish to read the original it is easy to ask your librarian to obtain a reprint for you from any medical library.

The authors set out to discover how well patients were doing who had previously suffered a primary patellar dislocation but who had neither had surgery nor reported recurrence of the patellar dislocation. They chose to study this because there is some controversy amongst surgeons about the best management after such an injury. Historically management has been conservative - meaning that the problem was managed without surgery - unless there was relevant damage to the cartilage or bone.

This management choice was based on medical publications that showed that 50-70% would not go on to experience recurrent dislocations. However the authors wondered if such a decision could be flawed because a number of patients do continue to be symptomatic, even though they may not actually be dislocating. So they set out to study the issue, and to determine the extent of continuing symptoms in patients from two high-volume sports clinics who, from their billing records, had been identified as having attended for "a primary lateral patellar dislocation during the study period and were treated without a surgical procedure to improve patellar stability".

The study group consisted of 104 individuals who had had their primary dislocation event at least two years before they were contacted, and who had not by that time had any patellar stabilisation surgery - and these patients were then followed up over a number of years, and reported their progress via PROMS questionnaires (Patient-Reported Outcome Score). Of the 104 - none of whom had initial stabilisation surgery - 26 actually did go on to have a recurrent dislocation, but the remaining 78 did not. 

The authors acknowledge that the study design was not perfect, but they feel confident in concluding that complete assessment of the success of nonoperative management of primary patellar dislocations require follow-up and investigation beyond simply noting and managing further dislocations, because at least some patients who do not have such recurrent dislocations are nonetheless significantly limited in their knee function, and would likely benefit from further treatment. Only 26.4 % of the patients without further dislocations reported they were able to return to desired sport activities without limitations following their dislocation.