Importance of the Topic

Acute patellar dislocations account for 2% to 3% of all knee injuries and have an estimated incidence of 5.8 per 100,000 patients per year [3, 5, 9]. Patellar dislocations commonly result in injuries to the soft-tissue structures on the medial aspect of the knee, particularly the medial patellofemoral ligament (MPFL), which can predispose patients to recurrent instability [3]. Patellar dislocations primarily affect young, physically active individuals, and recurrent instability can cause substantial morbidity [7]. Repetitive injury can lead to pain, inability to return to sports, decreased quality-of-life, early degenerative changes, and osteoarthritis [2].

The ideal treatment for primary patellar dislocations is controversial. Primary patellar dislocations generally are treated nonoperatively with physical therapy and/or bracing, but redislocation occurs in 15% to 44% of patients treated with nonoperative management. Therefore, several studies have compared clinical outcomes between surgical and nonsurgical treatment options [3]. Rigorous assessment of available evidence can inform clinicians regarding ideal treatment options for patients. This systematic review and meta-analysis presented findings on all randomized and quasi-randomized controlled trials (n = five trials; 344 patients) of surgical versus nonsurgical management for patients with primary lateral patellar dislocations.

Upon Closer Inspection

All of the included trials enrolled participants who had sustained a primary patellar dislocation as diagnosed by clinical examination. Nonsurgical management in all trials differed and consisted of initial immobilization in a cast or splint for a variable duration of time followed by active mobilization with variable physiotherapy regimens. There is considerable disagreement about the best nonoperative treatment approaches, and further research into identification of an ideal nonoperative management strategy has been previously recommended [8].

There was also variability in the reported surgical techniques across the included trials. Most techniques generally included repair or reconstruction of the soft tissue structures in the medial aspect of the knee, but specific techniques included MPFL suture repair, medial soft-tissue reefing with MPFL augmentation, combinations with lateral release, and MPFL reconstruction. Another systematic review addressing this topic found that the rationale for undertaking particular techniques rarely were reported despite considerable variability in surgical technique across studies in that review [8]. Additionally, anatomic considerations and diagnostic evaluation of associated conditions such as trochlear hypoplasia or generalized soft-tissue laxity were unreported, which prevents assessment of optimal techniques in specific patient populations.

Differential surgical expertise is a potential source of bias in surgical and nonpharmacologic trials [4, 6]. None of the included trials controlled for expertise in the surgical or nonsurgical treatment arms, so the expertise with which the interventions were administered could have varied across study groups. Expertise-based trials can minimize differential expertise bias by randomizing patients between clinicians with defined expertise in their procedure of choice [4].

Take-home Messages

This systematic review and meta-analysis found decreased risk of recurrent patellar dislocation and improved health-related quality-of-life scores following operative treatment of primary patellar dislocations at 2 to 5 years followup, but the quality of the evidence for all outcomes was graded low due to serious risk of bias from study limitations and imprecision in effect estimates. According to the Grading of Recommendations, Assessment, Development and Evaluation approach, low-quality evidence indicates that we have little confidence in the effect estimate and the true effect is likely to be substantially different from the estimate of effect itself [1]. Given a current lack of compelling data towards either operative or nonsurgical treatment, surgeon experience as well as individual patient values and preferences should primarily guide management.

Future research is required to compare specific nonoperative approaches and operative techniques, including consideration of specific risk factors for subsequent dislocation to provide clinicians’ managing this condition with critical information to inform treatment decisions.