Study designs of evaluations included in the review
Studies using any design with a minimum follow-up of 2 years were eligible for inclusion. The included studies were retrospective comparative studies or case series. The average follow-up ranged from 2 years 3 months to 8 years.
Specific interventions included in the review
Studies were eligible for inclusion if they used open or arthroscopic LRR or LRR with MR (MR was defined in the review). Studies involving distal bony realignment with tibial tubercle transfer or surgery without LRR were excluded.
Participants included in the review
Studies were eligible for inclusion if they involved patients over the age of 18 years with recurrent lateral patellar instability, defined as more than 1 episode of patellar dislocation or patellar subluxation. Studies were excluded if they identified patients with previous total knee arthroplasty or patellectomy, surgical treatment of an initial patellar instability episode, or surgical treatment of patellofemoral pain without stability. The included studies involved patients with either recurrent patellar dislocations or recurrent patellar subluxation, or patients with recurrent dislocation alone or recurrent subluxation alone.
Outcomes assessed in the review
Studies were eligible for inclusion if they reported post-operative failure as the primary outcome. Post-operative failure was defined as an episode of recurrent patellar dislocation or recurrent or persistent patellar subluxation during the post-operative period.
How were decisions on the relevance of primary studies made?
Three reviewers screened studies for relevance.