Background Lacertus syndrome is a dynamic proximal median nerve compression at the elbow, typically diagnosed clinically due to frequently normal electrodiagnostic findings and overlap with carpal tunnel syndrome. Surgical release has shown favorable outcomes; however, the available evidence remains limited and heterogeneous. This study aimed to systematically synthesize current evidence and quantify postoperative outcomes. Methods A systematic review was conducted in accordance with PRISMA 2020 guidelines (PROSPERO: CRD420261375852). Original clinical studies evaluating lacertus fibrosus release with postoperative outcomes were included. Primary outcomes were change in Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) score, immediate intraoperative return of flexor pollicis longus (FPL), flexor digitorum profundus to the index finger (FDP-II), and flexor carpi radialis (FCR) strength, and complications. QuickDASH change was pooled using random-effects models with imputed standard deviations and an assumed pre–post correlation of 0.5. Proportions were pooled for strength recovery and hematoma. Results Eight studies were included in qualitative synthesis; three clinical cohorts contributed quantitative data. Across two cohorts (n = 167 with paired data), QuickDASH improved by 22.2 points (95% CI 19.5–24.9). Immediate intraoperative return of strength was 98.8% (95% CI 96.7–99.6) across 309 procedures. Postoperative pain and numbness scores were low, and complications were uncommon, with one small self-limited hematoma reported. In the largest cohort, concomitant carpal tunnel syndrome (“double crush”) was present in 25.1% of cases. Conclusions In clinically diagnosed lacertus syndrome, lacertus fibrosus release—performed via mini-open or ultrasound-guided percutaneous techniques—is associated with substantial functional improvement, near-universal immediate intraoperative recovery of strength, and low reported complication rates. These findings should be interpreted in the context of limited observational evidence. The lacertus tetrad was recorded as an exploratory diagnostic enrichment, and prospective validation studies and comparative trials are required. Level of Evidence Level III (Therapeutic). Systematic review and meta-analysis of observational cohorts/case series with no randomized trials included.

Lacertus Syndrome: A Systematic Review and Meta‑Analysis

期刊论文
发表日期：

2026年6月14日

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J. Terrence Jose Jerome,
G. Surendran,
Thirumagal Kuppusamy

摘要

Background

Lacertus syndrome is a dynamic proximal median nerve compression at the elbow, typically diagnosed clinically due to frequently normal electrodiagnostic findings and overlap with carpal tunnel syndrome. Surgical release has shown favorable outcomes; however, the available evidence remains limited and heterogeneous. This study aimed to systematically synthesize current evidence and quantify postoperative outcomes.

Methods

A systematic review was conducted in accordance with PRISMA 2020 guidelines (PROSPERO: CRD420261375852). Original clinical studies evaluating lacertus fibrosus release with postoperative outcomes were included. Primary outcomes were change in Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) score, immediate intraoperative return of flexor pollicis longus (FPL), flexor digitorum profundus to the index finger (FDP-II), and flexor carpi radialis (FCR) strength, and complications. QuickDASH change was pooled using random-effects models with imputed standard deviations and an assumed pre–post correlation of 0.5. Proportions were pooled for strength recovery and hematoma.

Results

Eight studies were included in qualitative synthesis; three clinical cohorts contributed quantitative data. Across two cohorts (n = 167 with paired data), QuickDASH improved by 22.2 points (95% CI 19.5–24.9). Immediate intraoperative return of strength was 98.8% (95% CI 96.7–99.6) across 309 procedures. Postoperative pain and numbness scores were low, and complications were uncommon, with one small self-limited hematoma reported. In the largest cohort, concomitant carpal tunnel syndrome (“double crush”) was present in 25.1% of cases.

Conclusions

In clinically diagnosed lacertus syndrome, lacertus fibrosus release—performed via mini-open or ultrasound-guided percutaneous techniques—is associated with substantial functional improvement, near-universal immediate intraoperative recovery of strength, and low reported complication rates. These findings should be interpreted in the context of limited observational evidence. The lacertus tetrad was recorded as an exploratory diagnostic enrichment, and prospective validation studies and comparative trials are required.

Level of Evidence

Level III (Therapeutic). Systematic review and meta-analysis of observational cohorts/case series with no randomized trials included.