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EQUINE VETERINARY EDUCATION / AE / MAY 2018


on radiographs, applied a Robert Jones full leg bandage with 2 full-length wooden splints on the lateral and caudal aspects to stabilise the limb, and administered 4.4 mg/kg bwt phenylbutazone i.v. prior to immediate referral.


Case 3 A 10-month-old French Standardbred colt was found lame on pasture, was diagnosed with a comminuted fractured C2 based on radiographs, and immediately referred with a Robert Jones full leg bandage with a palmar splint.


Clinical and radiographic findings


Case 1 The gelding had a severe lameness apparent at the walk and rested the limb on the tip of the hoof (grade 5/5 American Association of Equine Practitioners [AAEP; Swanson 1984]) with a moderately swollen medial aspect of the carpus that was painful to flexion. Lateromedial (LM), dorsopalmar (DP), dorsomedial–palmarolateral oblique (DMPLO) and dorsolateral-palmaromedial oblique (DLPMO) radiographic projections showed a displaced sagittal C2 fracture and an oblique, displaced articular fracture of proximal MCII. The medial fragment of C2 showed marked medial dislocation, with several small fragments and pinpoint mineral opacities in/around the fracture gap, and soft tissue swelling on the medial aspect of the carpus.


Case 2 The mare was nearly nonweightbearing on the left forelimb due to carpal instability that resulted in a valgus deviation of the limb at the carpus (grade 5/5 AAEP [Swanson 1984]). Effusion and oedema of the soft carpal tissues was apparent and flexion of the carpus caused pain and obvious crepitation. Radiographs (DP, DLPMO and DMPLO) showed severe multiple, comminuted and displaced fractures of the ulnar, intermediate, and fourth carpal bones (C4) with carpus valgus, caused by collapse of the lateral aspect of MC and ABC joints. Numerous small fragments were visible on the lateral aspect of the carpus (Fig 1).


a) b)


Case 3 The colt was lame at the walk, with an exaggerated head and neck nod (grade 4/5 AAEP [Swanson 1984]), flexion of the carpus elicited a pain response, and swelling was apparent on the lateral aspect. Radiographs (LM, DP, DMPLO and DLPMO) showed a comminuted markedly displaced fracture of the medial border of C2, and thickening of the periarticular soft tissues.


Surgical details


Case 1 After premedication with sodium penicillin (Penicilline G, Panpharma, Luitr


e, France, 22,000 iu/kg bwt. i.v.), gentamicin


(Forticine, Vetoquinol, Lure, France, 6.6 mg/kg bwt. i.v.) and phenylbutazone (Phenylarthrite, Vetoquinol, Lure, France, 4.4 mg/kg bwt. i.v.) and sedation with acepromazine (Calmivet, Vetoquinol, Lure, France, 0.05 mg/kg bwt. i.v.), detomidine (Detogesic, Zoetis France SAS, Paris, France, 0.04 mg/kg bwt. i.v.) and morphine (Morphine Lavoisier; CDM Lavoisier, Paris, France, 1 mg/kg bwt. i.v.) the gelding was induced with ketamine (Ketamidor, Richter Pharma AG, Wels, Austria, 2.2 mg/kg bwt. i.v.) and diazepam (Valium; Roche SAS, Boulogne-Billancourt, France, 0.02 mg/kg bwt. i.v.) and positioned in left lateral recumbency. General anaesthesia was maintained with isoflurane (Isoflo, Zoetis France SAS, Paris, France) in oxygen and air in a semiclosed ventilating system, combined with a detomidine constant rate infusion (0.04 mg/ kg bwt/h). Aseptic preparation of the right front limb from the coronary band to the elbow, was done in preparation for a partial carpal arthrodesis of the MC and CMC joints. Arthroscopy was performed on the MC joint using a lateral approach and a medially-positioned instrument portal. The visible articular cartilage was removed with a manual curette for debridement of the medial aspect of the joint. Subsequently the position of the arthroscope and the curette were switched in the portal sites so the cartilage on the lateral aspect of the joint could be visualised and curetted. After debridement down to the subchondral bone, a cancellous bone graft (approximately 4 mL) was aseptically


c)


Fig 1: Preoperative radiographs of left carpus of Case 2. (a) dorsolateral-palmaromedial oblique projection, (b) dorsopalmar projection, (c) dorsomedial–palmarolateral oblique projection: severe multiple, comminuted and displaced fracture of the ulnar, the intermediate, and the fourth carpal bones (arrows).


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