Absence of Palmaris Longus Muscle and Its Clinical Significance in Africa Cadaveric and Clinical Studies: Systematic Review and Meta-Analysis

Background: Among the superficial flexor muscles of the upper limb, the Palmaris longus muscle is the most susceptible to anatomical variation. The most common anatomical variant is complete bilateral absence, followed by unilateral absence. Although considerable study has been conducted on the frequency of Palmaris longus muscle absences in Africa, much of it has been conducted at the national level. The pooled prevalence of Palmaris longus absence in Africa has not been established. Objectives: To assess the absence of Palmaris longus muscle and its clinical significance in Africa cadaveric and clinical studies: systematic review and meta-analysis. Methods: We thoroughly examined Google Scholar, PubMed/med line, Science Direct, Hinari, African online journals, Web of Sciences, Central, Embase, Scopus, Cochrane, and institutional repositories. The studies’ quality were assessed using the Newcastle–Ottawa Scale. The pooled prevalence of Palmaris longus muscle absences was estimated using a random-effects meta-analysis model. Data analysis was conducted using STATA 17; heterogeneity, funnel plots, and meta-regression were examined. Sensitivity analyses, publication bias, and subgroup analysis by study time code, location code, and sample size code were also carried out. Result: A total of 23 studies were included in the meta-analysis. The pooled prevalence of Palmaris longus absence in Africa was 14.0% (95% CI: 10.0–18.0). However, there was significant variation in reported prevalence rates, as seen by the significant heterogeneity found across studies (I2 = 99.13%). The results were not significantly changed by sensitivity analysis. Conclusions and recommendation: This study found that the Palmaris longus muscle is absent in 14% of African populations. Comparison with international studies revealed both similarities and differences, influenced by methodology and genetic factors. Clinicians should consider this prevalence when advising patients requiring tendon grafts. Further long-term studies using imaging techniques (MRI; ultrasound) are recommended to improve understanding in African populations and globally.