REVERSE OBLIQUE OLECRANON FRACTURE

Introduction In oblique olecranon fracture, fracture line begins in the trochlear notch and proceeds distally to the dorsal cortex of the ulna. We have experienced a nonunion of reverse oblique fracture. Hypothesis Reverse oblique olecranon fracture has instability. Materials & Methods 130 patients with an olecranon fracture were retrospectively evaluated. Inclusion criteria are that fracture line begins at the base of the coronoid process, distal portion of the trochlear notch, and proceeds proximally to the dorsal cortex of the ulna on the lateral radiograph. Fractures with articular comminution were excluded. Results Seven patients met the criteria. They were associated with local injuries: anterior translation of the proximal radius and ulna, fracture of the medial epicondyle or the lateral condyle of the humerus. One out of five patients treated with tension band wiring (TBW) was revised with screw fixation because of nonunion. Discussion The associated injuries suggested the anterior and valgus instability. A nonunion case suggests a requirement of more secure fixation. However, these findings are common in distal olecranon fracture. Therefore, the instability in our series is due to the distal location of fracture on the trochlear notch rather than reverse obliquity. The reverse obliquity attributes to small proximal fragment. Conclusion Reverse oblique olecranon fracture has instability because of its distal location. It should be distinguished from simple, stable fracture.