Focal humero-ulnar impingement following subtotal coronoid ostectomy in six dogs with fragmented medial coronoid process.

Abstract

OBJECTIVE: To report acute eburnation of joint cartilage at the humeral trochlea following subtotal coronoid ostectomy (SCO) in a clinical case series of six elbows. MATERIAL AND METHODS: Six dogs (median BW 27.1 kg; median age 7.5 months) with fragmented medial coronoid process (FCP) and varying degree of radio-ulnar incongruence (RUI) (mean 2 mm) were treated with SCO using an arthroscopic burr. Second look arthroscopy 4-12 weeks later was performed either because of recurrent or persistent lameness in three dogs. In the others, second-look arthroscopy was scheduled prospectively because of RUI, which was thought to be a risk factor for the observed humero-ulnar impingement. RESULTS: All six elbows had a 1-2 mm wide line of focal full-thickness cartilage loss along the edge of the SCO, while the opposing trochlea had diffuse cartilage damage of Outerbridge grade III-IV, indicating focal humero-ulnar impingement. None of the elbows showed repeated FCP. CONCLUSION: In some cases SCO might lead to focal humero-ulnar impingement along the osteotomy line. CLINICAL SIGNIFICANCE: Whether this relays to variations in respect the amount of resected bone (too much vs. too less) or concomitant joint pathologies like RUI or joint instability remains unknown and warrants further studies.