Subchondral lucencies of the proximal tibia in 17 horses.

OBJECTIVE: To describe subchondral lucencies (SCL) in the equine proximal tibia, several treatment options, and clinical outcomes. STUDY DESIGN: Retrospective study. ANIMALS: Seventeen horses with proximal tibial SCL. METHODS: Medical record and radiograph review. Follow-up was obtained via examination and radiography when possible and by telephone and race records when required. The median duration of follow-up was 20 months (range, 0-48). RESULTS: Proximal tibial SCL were associated with lameness in 14 of 17 horses. Subchondral lucencies were primary in 11 horses and secondary to an ipsilateral medial femoral condyle SCL in six horses. One foal with a primary SCL was euthanized because of osteomyelitis. Six horses ≤1 year old with primary SCL were managed with exercise restrictions only; SCL in three horses without lameness decreased in size, whereas three horses with lameness did not improve. One young horse treated with surgical debridement failed to improve and was euthanized. Lameness resolved in three horses with primary tibial SCL treated with screw fixation. Screw fixation of secondary SCL in five horses led to a reduction in SCL size and degree of lameness. CONCLUSION: Primary tibial SCL healed with rest in 3 non-lame young horses with small SCL, but was not successful in lame horses with larger SC. Radiographic size and associated lameness improved or resolved with screw fixation in primary and secondary proximal tibial SCL. CLINICAL SIGNIFICANCE: Primary tibial SCL that did not cause lameness healed with conservative management, but persistent primary and secondary tibial SCL required screw fixation to reduce lameness.

Ex vivo strength comparison of bioabsorbable tendon plates and bioabsorbable suture in a 3-loop pulley pattern for repair of transected flexor tendons from horse cadavers.

OBJECTIVE: To test the failure strength and energy of 2 bioabsorbable implants applied to transected deep digital flexor tendons (DDFT) from adult horses. STUDY DESIGN: Ex vivo biomechanical experiment. SAMPLE POPULATION: Twelve pairs of deep digital flexor tendons harvested from the forelimbs of fresh equine cadavers. METHODS: Poly-L-lactic acid tendon plates were custom manufactured for application to the cylindrical surface of an adult equine deep digital flexor tendon. Twelve pairs of DDFTs were transected 2 cm distal to the insertion of the distal check ligament of the deep digital flexor tendon. One tendon of each pair was randomly selected for repair with a biodegradable plate or a 3-loop pulley method. Size 2 polydioxanone suture was used in both repairs. Repairs were tested in tension to failure, with peak force (PF) and total energy (TE) at repair failure recorded in Newtons (N) and Joules (J), respectively. A paired t-test was used for statistical evaluation with a significant level set at P< or = .05. RESULTS: Mean+/-SD PF for failure of plated tendons (1507.08+/-184.34 N) was significantly greater than for sutured tendons (460.86+/-60.93 N). TE was also significantly greater for failure of plated tendons versus sutured tendons. CONCLUSIONS: Plate fixation of transected cadaver DDFTs appear to have superior immediate failure strength than 3-loop pulley repairs. CLINICAL RELEVANCE: Whereas in vivo testing is required, a bioabsorbable tendon plate may provide initial increased strength to support tendon healing and decrease external coaptation requirements.

Segmental ostectomy of the second and fourth metacarpal and metatarsal bones in horses: 17 cases (1993-2002).

OBJECTIVE: To determine clinical findings in and outcome of horses with fractures of the second or fourth metacarpal or metatarsal bone that underwent segmental ostectomy, leaving the proximal and distal portions of the bone undisturbed. DESIGN: Retrospective case series. ANIMALS: 17 horses. PROCEDURES: Medical records were reviewed, and information on signalment, affected bone, lesion type, surgical procedure, amount of bone removed, and surgical and postsurgical complications was obtained. Follow-up information was obtained through telephone conversations with owners, trainers, and referring veterinarians. RESULTS: One horse had a fracture involving the distal third of the second metacarpal bone; 13 had fractures involving the middle third of the second metacarpal bone (n = 4), fourth metacarpal bone (5), or fourth metatarsal bone (4); and 3 had fractures involving the proximal third of the second (2) or fourth (1) metacarpal bone. Affected portions of the bones were surgically resected, leaving the proximal and distal portions undisturbed. All horses returned to previous performance levels without evidence of lameness. Cosmetic results were good to excellent. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that horses with a complicated injury of the proximal, middle, or distal portion of the second or fourth metacarpal or metatarsal bone may be successfully treated by means of segmental ostectomy of the abnormal portion of the bone.