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 (P = .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 (P = .027). Total time of implantation, including osteotomy preparation, was a mean 155 seconds shorter with the Olecranon Sled versus the traditional tension band (P < .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 (P > .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.

Biomechanical comparison of long, short, and extended-short nail construct for femoral intertrochanteric fractures.

OBJECTIVES: Short and long cephalomedullary (CM) nails are commonly used construct for fixation of intertrochanteric (IT) fractures. Each of these constructs has its advantages and its shortcomings. The extended-short (ES) CM nail offers a hybrid between long and short nail design that aims to combine their respective benefits. The goals of this study were to (1) biomechanically evaluate and compare construct stiffness for the long, short and ES constructs in the fixation of IT fractures, and to (2) investigate the nature of periprosthetic fractures of constructs implanted with these various designs. METHODS: Eighteen synthetic femora were used to evaluate three types of fracture fixation constructs. Axial compression, bending, and torsional stiffness were reported for both stable and comminuted IT fracture models. All comminuted fracture constructs were loaded to failure in axial compression to measure failure loads and evaluate periprosthetic fracture patterns. RESULTS: Stiffness were similar among constructs with few exceptions. Axial stiffness was significantly higher for the short nail compared to the long nail for the comminuted model (p= 0.020). ES nail constructs exhibited a significantly higher failure load than short nail constructs (p = 0.039). Periprosthetic fractures occurred around the distal interlocking screw in all constructs. CONCLUSIONS: Nail length and position of interlocking screw did not alter the biomechanical properties of the fixation construct in the presented IT fracture model. Periprosthetic fractures generated in this study had similar patterns to those seen clinically. This study also suggests that if a periprosthetic fracture is to occur, there is an increased probability of it happening around the site of the interlocking screw, regardless of nail design.

Forearm fractures in children and adolescents: a practical approach.

This article presents a practical approach to management of displaced radius and ulna fractures in children and adolescents while addressing areas of controversy. Nonsurgical and surgical management are discussed. A technique for intramedullary fixation of the radius and ulna is presented in detail.