Evaluation of the Effect of a Dynamic Proximal Ulnar Osteotomy on Radio-ulnar Congruence in 26 Elbows

Introduction
Our objective was to investigate resultant radio-ulnar joint modification using computed tomography (CT) after a Bi-Oblique Dynamic Proximal Ulnar Osteotomy (BODPUO) had been performed for the treatment of perceived elbow incongruence.

Materials and methods
Dogs operated by a single surgeon, with a BODPUO and for which a CT-scan study was available, preoperatively (PreO) and after completion of the osteotomy healing process, were included. Radio-ulnar space measurements were taken on transverse, frontal and sagittal CT projections (as defined by Holsworth et al.), preoperatively, 6 weeks postoperatively (PostO) and after radiographically determined healing of the osteotomy (12 weeks PostO). Additional transverse measurements were taken at the cranio-distal extent of the ulnar osteotomy line between the caudal radial cortex and the cranial ulnar cortex.

Results
Twenty-six elbows were included into the study. In addition to elbow incongruence, 21 elbows were affected by an MCP lesion in isolation, 2 by an ununited anconeal process (UAP) coupled with an MCP lesion and 3 by an osteochondritis dissecans (OCD) coupled with an MCP lesion. All osteotomies (26/26) were radiographically healed at the last CT examination. The mean elbow extension angle PreO, at 6 and 12 weeks PostO were 119±13°, 119±8° and 121±10° respectively, which were not statistically different from one another. (ANOVArm; p-value = 0.678). LCP (.165cm vs. .270cm), Tr3 (.114cm vs. .230cm), Tr2 (.087cm vs. .129cm) measurements were statistically greater at twelve weeks post operatively than pre-operatively. None of the other measurements taken at the level of the elbow were statistically different.  [...]