Biomechanical Comparison of Olecranon Sled Versus Intramedullary Screw Tension Banding for Olecranon Osteotomies.

BACKGROUND

Olecranon osteotomies are frequently performed to gain access to the distal humeral articular surface. Repair of the osteotomy or fixation of a simple 2-part olecranon fracture with traditional tension band construct is often plagued by complication. Proximal migration and irritation attributed to hardware are common complications of the standard construct of an intramedullary screw with tension band and are causes for reoperation.

PURPOSE

To compare the biomechanical performance, time of implant, and prominence of an intramedullary screw and tension band construct with that of a newer low-profile continuous loop tension band (Olecranon Sled) construct in an olecranon osteotomy model.

STUDY DESIGN

Controlled laboratory study.

METHODS

Chevron osteotomies were created in 6 matched pairs of fresh-frozen human elbows (mean age, 66 ± 16 years). Each matched pair was then randomly divided into 1 of 2 groups: fixation with a screw and tension band construct or the Olecranon Sled. Bone mineral density, implant prominence, and time for implantation were recorded. Following olecranon fixation, each specimen underwent cyclic loading of 0 to 10 N for 100 cycles (to simulate unresisted active range of motion) and then 0 to 500 N for 500 cycles (to simulate pushing up from a chair) to measure for any displacement at the osteotomy site. The constructs were then loaded to failure and compared.

RESULTS

No differences were found in bone mineral density between the 2 groups ( = .290). When measured from the tip of the olecranon, the continuous loop tension band had a medial prominence of only 3.57 ± 0.4 mm, as opposed to the intramedullary screw fixation of 7.288 ± 0.762 mm ( = .027). Total time of implantation, including osteotomy preparation, was a mean 155 seconds shorter with the Olecranon Sled versus the traditional tension band ( < .05). Because of the fracture of 1 specimen during cyclic loading, it and its matched counterpart were excluded, and only 5 matched pairs were analyzed for displacement and load to failure. There were no significant differences between groups in load to failure or displacement during cyclic loading ( > .05).

CONCLUSION

The Olecranon Sled device was found to have no difference in biomechanical strength from that of the standard intramedullary screw with tension band construct. The Olecranon Sled was also found to be significantly less prominent while being faster to implant than the intramedullary screw.

CLINICAL RELEVANCE

Evaluating an alternative option to the standard tension band construct is important for patients with olecranon fractures or osteotomies, as standard techniques have been fraught with hardware issues and need for revision surgery.