The Impact of Suture Caliber and Looped Configurations on the Suture-Tendon Interface in Zone II Flexor Tendon Repair.

PURPOSE: To evaluate the impact of suture caliber and looped configurations on the integrity of 4-strand modified Kessler zone II flexor tendon repairs during progressive cyclic loading. METHODS: Seventy-two flexor digitorum profundus tendons from 18 fresh human cadaver hands were divided into 4 repair groups. Thirty-six matched tendons underwent repair using either a 4-0 looped or 4-0 single-stranded suture, and an additional 36 tendons underwent 3-0 looped or 3-0 single-stranded repairs. Repair strength was tested by progressive cyclic loading. The force generating 2-mm gap formation, ultimate failure, and the mechanism of failure were recorded for each test. The impact of looped versus single-stranded configurations and the effect of tendon cross-sectional area on repair integrity were analyzed for each suture caliber. RESULTS: There was no statistically significant difference between groups regarding the force to 2-mm gap formation or ultimate failure, and all values exceeded the minimum threshold of 27 N required to withstand an early active range of motion rehabilitation protocol. The use of a 3-0 caliber suture resulted in a significantly higher proportion of repairs failing by suture pullout through the tendon substance, including 63.5% of looped and 38.9% of single-stranded core sutures. By comparison, this occurred in 11.1% of 4-0 looped and 0% of 4-0 single-stranded sutures. Larger tendon cross-sectional areas were associated with more robust repairs, particularly in the 3-0 looped group. CONCLUSIONS: In a human cadaver flexor tendon repair model, there was no significant difference in the mean force to failure between all 4 flexor tendon repair constructs under progressive cyclic loading. However, the 3-0 caliber suture failed more frequently by suture pullout, particularly with the use of a looped suture. CLINICAL RELEVANCE: Four-strand flexor tendon repairs using a 3-0 caliber suture are more prone to early failure by suture pullout under progressive cyclic loading compared with a 4-0 caliber suture.

L5 nerve root decompression after malunion of surgically managed vertically unstable pelvic ring injuries.

We describe the outcomes of late decompression of the L5 nerve root after malunion of surgically managed pelvis injuries. Four patients underwent decompression of the L5 nerve root. Surgery included hemilaminotomy with facetectomy at L5-S1 followed by decompression of the L5 nerve root laterally from the surrounding displaced sacral ala. L5-S1 fusion was not performed. Radiographs and Oswestry Disability Index (ODI) scores were obtained for each patient at latest follow-up. In all patients, adequate decompression required removal of bone to the anterior aspect of the sacral ala inferiorly to the level of the superior endplate of S1, and there was resolution of L5 radicular pain. Late decompression of the proximal course of the L5 nerve root provided pain relief without resultant radiographic pelvis or L5-S1 instability.