Imaging-based prevalence of the peroneus quartus muscle and its association with peroneal tendon pathology: a systematic review and meta-analysis.

Abstract

To determine the imaging-based prevalence of the peroneus quartus muscle and to quantify concurrent peroneal tendon pathology among individuals with this anatomical variant. A systematic review and meta-analysis were conducted following PRISMA 2020 guidelines. PubMed, EMBASE and Cochrane were searched from inception to 2025 for imaging-based studies reporting peroneus quartus prevalence. Overall prevalence was estimated using generalized linear mixed models with random effects. Heterogeneity was assessed using the I² statistic. Risk of bias was evaluated using design-specific Joanna Briggs Institute critical appraisal checklists. Subgroup analyses examined sex and laterality distribution among positive cases. Seventeen studies comprising 3,725 ankle imaging examinations were included. The overall prevalence of the peroneus quartus was 11% (95% CI: 8-15%), with substantial heterogeneity (I² = 80.5%). Among six studies (315 positive ankles), peroneal tendon pathology was present in 51.4% (95% CI: 41.9-60.8%). In three studies reporting tears in ankles with and without the peroneus quartus, its presence was associated with higher odds of peroneal tendon tears (pooled odds ratio 3.40, 95% CI: 2.03-5.68; I² = 0%; p < 0.001). The majority of studies (58.8%) were classified as low risk of bias. The peroneus quartus muscle is identified in approximately one of nine ankle imaging examinations, and in studies with a comparison group its presence was associated with higher odds of peroneal tendon tears. This supports the proposed crowding-effect hypothesis, although a causal relationship remains to be established.