Biomechanical evaluation of fixation of the coracoclavicular stand-alone cow-hitch suture reconstruction in comparison to two established techniques for highly unstable distal clavicle fractures (Neer type V)

Abstract

BackgroundTreatment of displaced distal clavicle fractures with bony avulsion of the coracoclavicular (CC) ligaments often warrants surgical fixation, yet a gold-standard surgical technique is to be defined. The purpose of this study was to compare the biomechanical fixation strength of a new fixation technique, the CC stand-alone Cow-Hitch suture reconstruction, and to compare this technique with a clavicle hook plate and a lateral locking plate with CC suture reconstruction. MethodsSimulated Neer type V distal clavicle fractures fractures of the clavicle were created in 18 cadaveric shoulders, which were matched by age and gender in 3 groups: (1) clavicle hook plate (Group HP), (2) lateral locking plate fixation with CC suture reconstruction (Group LPCC) and (3) CC stand-alone suture reconstruction using the Cow-Hitch technique (Group CH). After preconditioning with 25 N for 10 cycles the specimens were cycled in the coronal plane for 500 cycles from 10N to 70N. Displacement and ultimate load to failure were documented and analyzed with the data acquisition system. ResultsThere was a significant difference in the fracture displacement during cyclic loading between the LPCC group and the HP group (0.6 vs. 1.7 mm; p=0.02), and between CH and HP groups (0.5 vs. 1.7 mm; p=0.004). Fracture displacement was not different between the LPCC and the CH groups (p=0.544). The CH group and the LPCC group showed a significant higher stiffness compared to the HP group (p<0.001 and p=0.003, respectively). The CH group showed a significant higher ultimate load to failure compared with the HP group (429 vs. 172 N; p=0.005), and showed a tendency towards higher ultimate load to failure when compared with the LPCC group (429 vs. 258 N; p=0.071). ConclusionThe CC stand-alone Cow-Hitch suture reconstruction and the locking plate with CC reconstruction showed higher fixation strength compared with the hook plate for simulated Neer type V distal clavicle fractures. There was a tendency of higher ultimate load to failure with the Cow-Hitch technique compared with the lateral locking plate with CC suture reconstruction, and given the potential advantages of less soft tissue stripping, metal-free fixation, low costs, and simple surgical technique, clinical application of the all-suture CC reconstruction using the Cow-Hitch for Neer type V distal clavicle fractures appears warranted.