Comparison of Locking and Grasping Loops in Similar Repair Techniques: A Systematic Review and Meta-analysis

PURPOSE: Numerous studies have compared locking and grasping loop tendon repair configurations, with varying results. This study aimed to synthesize biomechanical evidence from experimental laboratory studies comparing these two configurations under linear static loading.

METHODS: MEDLINE and Cochrane CENTRAL databases were searched for studies comparing locking and grasping configurations in flexor tendon repairs using linear static loading. Meta-regressions and subgroup analyses were performed to identify properties in repair configurations that could explain heterogeneity between studies.

RESULTS: The search yielded 14 studies for the review. Locking repairs provided greater ultimate and 2-mm gap loads than grasping repairs, with the advantage being most pronounced when high tensile strength suture materials were used: the mean ultimate load was 40 N in grasping repairs and 7.9 N higher (95% CI, 5.6-10 N, I2 = 87%) in locking repairs. A similar trend was observed for the 2-mm gap load, with a mean of 31 N in grasping and 5.8 N higher in locking repairs (95% CI, 3.6-8.1 N, I2 = 83%).

CONCLUSIONS: In experimental laboratory settings, locking loop configurations provide superior ultimate and 2-mm gap loads compared to grasping loop configurations, particularly with high-strength suture materials. Given the high between-study heterogeneity and that the included studies were conducted in laboratory settings, additional similar biomechanical comparisons may have limited incremental value; clinical studies are needed to determine whether these biomechanical differences translate into improved clinical outcomes.

CLINICAL RELEVANCE: Locking loop tendon repairs appear to withstand greater loads than grasping loop repairs, suggesting a potential biomechanical advantage that may be clinically relevant.