Orthopaedic Journal of Sports Medicine, 6(12), 1-7, Dec 2018
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 traditioinal 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 continous 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 frozen-fresh human elbows (mean age, 66 +/- 16 years). Each matched pair was then randoly divided into 1 or 2 groups; fixation with a screw and tension band construct of 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 desnsity between the 2 groups (P=0.290). When measured from the tip of the olecranon, the continous loop tension hand had a medial prominense of only 3.57 +/- 0.4 mm, as opposed to the intramedullary screw fixation of 7.288 +/- 0.762 mm (p = 0.027). Total time of implantation, including osteotomy preparation, was a mean 155 seconds shorter with the Olecranon Sled versus the traditional tension band (P < 0.05). Because of the fracture of 1 specimen during cyclic loading, it and its matched counter part 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 displacemnt during cyclic loading (P > 0.05).
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 signficantly less prominent while being faster to implant than the intramedullary screw.
Clinical Relevance: Evaluating an alternative option to the standard tension band constrct is important for patients with olecranon fractures or osteotomies, as standard techniques have been fraught with hardware issues and need revision surgery.