Surgical versus non-surgical interventions for treating patellar dislocation

Patellar dislocation occurs when the patella disengages completely from the trochlear (femoral) groove. Following reduction of the dislocation, conservative rehabilitation with physiotherapy may be used. Since recurrence of dislocation is common, some surgeons have advocated surgical intervention in addition to rehabilitation.

The purpose of this review was to assess the clinical and radiological outcomes of surgical, compared with non-surgical, interventions for treating people with primary or recurrent patellar dislocation.

We searched the Cochrane Bone, Joint and Muscle Trauma Group's Specialised Register, the Cochrane Central Register of Controlled Trials (The Cochrane Library), MEDLINE, EMBASE, AMED, CINAHL, ZETOC, Physiotherapy Evidence Database (PEDro), and a variety of other literature databases and trial registries. Corresponding authors were contacted to identify additional studies. Date searched: August 2010.

Eligible for inclusion were randomised and quasi-randomised controlled clinical trials evaluating surgical versus non-surgical interventions for treating lateral patellar dislocation.

Two reviewers independently examined titles and abstracts of each identified study to assess study eligibility, extract data and assess risk of bias. Primary outcomes assessed were the frequency of recurrent dislocation, and validated patient-rated knee or physical function scores. When appropriate, data were pooled. Risk ratios were calculated for dichotomous outcomes, and mean differences for continuous outcomes.

Five studies (339 participants) were included. All studies had methodological shortcomings, especially the two quasi-randomised trials that presented a high risk for selection bias. Follow-up was a minimum of two years in two studies and between five and seven years in three studies. There was no significant difference between surgical and non-surgical management of primary (first-time) patellar dislocation in the risk of recurrent dislocation (47/182 versus 53/157; risk ratio 0.81, 95% confidence interval 0.56 to 1.17; 5 trials), Kujala patellofemoral disorder scores (mean difference 3.13, 95% confidence interval -7.34 to 13.59; 5 trials) nor the requirement for subsequent surgery (risk ratio 1.09, 95% CI 0.72 to 1.65; 3 trials). Adverse events were reported by one trial, citing four major complications that occurred in the surgical group. No randomised controlled trials have assessed populations with recurrent patellar dislocation.

There is insufficient high quality evidence to confirm any significant difference in outcome between surgical or non-surgical initial management of people following primary patellar dislocation, and none examining this comparison in people with recurrent patellar dislocation. Adequately powered randomised, multi-centre controlled trials, conducted and reported to contemporary standards are recommended.