Effects of longitudinal compression before and after transection of the accessory ligament of the superficial digital flexor (SDF) muscle were measured in eight equine cadaver forelimbs. When compression was increased from 890 N to 3115 N, the metacarpophalangeal (MCP) and carpal joints hyperextended 20 degrees and 4 degrees, respectively, and strain in the SDF and deep digital flexor tendons was increased 3.5% and 1.4%, respectively. The accessory ligament did not elongate. Immediately after transection of the accessory ligament at 3115 N load, a 2.8 mm gap formed between the transected ends of the accessory ligament, and the muscle belly of the SDF elongated and moved distad. The MCP joint hyperextended 15.8% further and strain of the SDF tendon increased 11.2% further. These results show that the accessory ligament transferred load in the SDF musculotendinous unit away from the muscle belly and that desmotomy altered this function. Decrease in the MCP joint angle indicated that the accessory ligament contributed to the support of the MCP joint under load. Increase in SDF strain after desmotomy was probably influenced by the change in the moment about the MCP joint and increased length of the SDF musculotendinous unit.

Two mares with multiple carpal bone fractures, malarticulation and degenerative joint disease were successfully treated with unilateral arthrodeses of the antebrachiocarpal, middle carpal, and carpometacarpal joints. Arthrodesis was achieved by removal of articular cartilage, autogenous cancellous bone graft, and double dynamic compression plating. In one horse, wedge ostectomy corrected the severe, acquired angular limb deformity. External coaptation supplemented the internal fixation. Postoperative complications were limited to cast sores that healed with treatment, although protracted in one horse. Both mares adapted to the "peg leg" condition and ambulated without pain by 3 months. The first mare treated survived for at least 2 1/2 years after surgery and has had at least one foal. The most recently treated mare will be bred next year.

Five New World camelids were admitted to the Western College of Veterinary Medicine between 1996 and 2003 for evaluation of femoral fractures. There were three alpacas and two llamas. Four of the animals were female and three were less than 3 months of age. Fracture configurations consisted of distal physeal fractures (three), a comminuted diaphyseal/metaphyseal fracture, and a transverse diaphyseal fracture. Fractures were diagnosed with a combination of physical examination and radiographs in all cases. All five fractures were repaired with internal fixation and three animals were discharged from the hospital with fractures that healed. One cria underwent successful internal fixation but died from pulmonary oedema during recovery from anaesthesia. Postoperative complications were rare and limited to inadequate fracture stability in one alpaca and prolonged recovery to weight bearing in another. One llama with a comminuted metaphyseal fracture, repaired with a 4.5 mm dynamic compression plate, subsequently had catastrophic failure of the bone 17 days after surgery. Overall the clients were pleased with the outcome of discharged animals. Although femoral fractures are considered rare, they pose a unique opportunity for the large animal veterinarian to successfully achieve fracture union with the aid of internal fixation.

Reasons for performing study Clodronic acid (CA) is a bisphosphonate which inhibits bone resorption through inhibition of formation/dissolution of hydroxyapatite crystals and by direct cellular effects on osteoclasts. The study was conducted to assess the short‐ and long‐term effectiveness of CA for the control of lameness associated with navicular syndrome. Objectives To demonstrate the effectiveness of CA in navicular syndrome. Study design Randomised, multi‐centre, double‐masked, placebo controlled field trial in client‐owned horses. Methods Horses with unilateral or bilateral forelimb lameness (AAEP lameness scale grade ≥2); positive anaesthesia of the distal palmar digital nerve(s); radiographic evidence of navicular syndrome and the absence of other causes of lameness were eligible for enrolment. Horses were randomised to treatment groups in a 3:1 ratio of CA to saline control. Treatment was administered once via intramuscular injection at 1.2 mg/kg bwt (maximum 765 mg CA or 15 ml saline). Efficacy was assessed by comparing lameness grades before and after treatment. Results 146 horses of various breeds were enrolled at 6 sites in Germany and US. At 8 weeks, horses in the CA group had a significantly higher success rate than horses in the control group (least squares mean 74.72% vs. 3.30%; P = 0.0028). Efficacy was sustained through 180 days in 66% of horses. Adverse events were few and considered to be mild and transient. Conclusions Clodronic acid was safe and effective in navicular syndrome. Ethical animal research: Owners gave informed consent for their horses’ inclusion in the study. Sources of funding: Dechra Ltd. Competing interests: The late Dr Frevel was a consultant to Omnimedic GbR, which has applied for a patent for the use of clodronic acid for navicular syndrome. Dr Poole is employed by Dechra.

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