Optimization of lesser tuberosity osteotomy repair: a biomechanical assessment of suture tensioning, repair configuration, and type of suture.

BACKGROUND

Lesser tuberosity osteotomy (LTO) is an effective method to manage the subscapularis for total shoulder arthroplasty but requires adequate compression and stability for healing after repair. The optimal configuration and type of sutures for LTO repair are unknown. The effect of variable surgeon strength on repair is similarly an unknown factor and may play a role in construct repair security. This study measured, in vitro, the effect of suture number and the effect of surgeon manual strength on repair. We hypothesized that increasing the number of sutures or selecting suture tapes over conventional sutures produces a stronger repair. Secondarily, we hypothesized that differences in surgeon manual strength introduce variability into the strength of the repair.

METHODS

A custom jig was used to mechanically test conventional #5 braided suture and 1.7 mm suture tape. Combinations of 1, 2, 3, 4, and 5 sutures of each type were preloaded, cyclically loaded, and loaded to ultimate failure. After measuring grip strength and traction strength of 3 orthopedic surgeons, we tested their hand-tied repairs and compared them to a self-tensioning suture cerclage system.

RESULTS

Increasing the number of sutures significantly increased the strength of repair in a relatively linear fashion (P < .001). Tests with #5 sutures showed a significant difference between 3 and 4 sutures (P = .005); however, those with suture tape did not. All 3 surgeons demonstrated significantly different grip strengths. Surgeon 2 showed greater traction strength than Surgeon 1 (P < .001) and Surgeon 3 (P < .001). Hand-tied repairs mirrored this trend, as those performed by Surgeon 2 were stronger than those by Surgeon 1 (P = .041) and Surgeon 3 (P = .028). A self-tensioning suture cerclage system was equivalent to all surgeons' hand-tied repairs.

CONCLUSION

Four sutures appear to be an efficient number for LTO repair, as we observed no appreciable increase in strength with the addition of a fifth suture. There was no difference in strength between the suture types. Hand-tied repairs exhibit significant differences in strength among surgeons. If a surgeon considers this variation unfavorable, they may opt to use a tensioning device to ensure consistent repair strength according to their clinical judgment.