Triceps-sparing extra-articular step-cut olecranon osteotomy for distal humeral fractures: an anatomic study.

Background: This anatomic study investigated the distal humeral articular surface exposure achievable through a triceps-sparing oblique extra-articular osteotomy of the olecranon with a step-cut modification compared with the anconeus flap transolecranon apex distal chevron osteotomy. In addition, the bone contact surface areas of the osteotomized surfaces after transolecranon and extra-articular osteotomies were compared.

Methods: Seven pairs of fresh adult cadaveric elbow joints were examined. Each of the right elbows underwent triceps-sparing extra-articular step-cut olecranon osteotomy (SCOOT) with an anconeus flap, and the left elbows underwent the anconeus flap transolecranon apex distal chevron osteotomies (CO). The articular surface exposed by each of the osteotomy techniques was then digitally analyzed using a 3-dimensional measurement system. The bone contact surface area of the osteotomized surfaces was also assessed.

Results: The percentage of total joint exposed by the SCOOT group was less than the CO group (SCOOT: 64% ± 3% vs. CO: 73% ± 3%; P = .002). There was significantly greater bone contact surface area of the osteotomized surfaces in the SCOOT group compared with the CO group (SCOOT: 1172 ± 251 mm vs. CO: 457 ± 133 mm; P = .002).

Conclusion: The triceps SCOOT procedure with an anconeus flap provides excellent distal humeral articular surface exposure with the added benefit of a substantially increased (2.6-times) bone contact surface area of the osteotomized surfaces.