Prevalence and Site of Concomitant Osteochondral Injuries in Patients With Acute Lateral Patellar Dislocation: A Systematic Review and Meta-analysis

Background: Osteochondral injuries (OCIs) are common in patients with acute lateral patellar dislocation, which can produce both short- and long-;term adverse effects. However, the pattern of these injuries warrants further analysis, especially in relation to patient age. Purpose: To determine the overall prevalence of concomitant OCIs as well as the prevalence differences based on location and age after acute lateral patellar dislocations. Study Design: Systematic review; Level of evidence, 4. Methods: A comprehensive search of PubMed, Embase, Web of Science, and Cochrane Library was completed from inception to July 20, 2022. All articles reporting the prevalence of OCI were included. The sample characteristics such as age, study design, magnetic resonance imaging diagnostic data, and the number of patients with OCI were extracted. The Methodological Index for Non-Randomized Studies (MINORS) was used for quality assessment. The overall and per-;site injury rates were calculated, and the prevalence was stratified by age-;group (<= 16 and >16 years) and compared. Results: The systematic review included 39 studies involving 3354 patients. MINORS scores were 11.94 +/- 1.98 and 16 +/- 3.46 in the noncomparative and comparative studies, respectively. The overall prevalence of bone bruises and OCI was 89.6% (95% CI, 77.4%-97.7%) and 48.8% (95% CI, 39.0%-58.7%), respectively. In both overall and >16-year-old patients, the lateral femoral condyle (LFC) was the most common site of bone bruise (90.5% [95% CI, 84.0%-95.6%] and 91.5% [95% CI, 84.3%-96.9%], respectively); however, the medial patellar bruise was more common in patients <= 16 years (89.2% [95% CI, 82.9%-94.4%]). Among the pooled sites of OCI, the medial patella accounted for the largest proportion (36.9% [95% CI, 28.0%-46.3%]). OCIs were more common in patients >16 years (52.6% [95% CI, 39.4%-65.6%]) than in patients <= 16 years (46.6% [95% CI, 33.2%-60.3%]). Conclusion: Bone bruises on the LFC were most prevalent overall and in patients >16 years, whereas bone bruises on the medial patella were more prevalent in patients <= 16 years. OCIs were frequently seen in patients >16 years, with the most common site being the medial patella.