Single-incision percutaneous drilling technique to achieve hemiepiphysiodesis of the distal metacarpus in foals with metacarpophalangeal varus deformities

Single-incision drilling technique to achieve hemiepiphysiodesis of the distal metacarpus - complications and outcome in 207 foals with metacarpophalangeal varus deformities

OBJECTIVE

To report the outcome of foals treated for metacarpophalangeal varus deformity with a single-incision drilling technique for hemiepiphysiodesis of the distal lateral metacarpal physis.

STUDY DESIGN

Retrospective case-control cohort study.

ANIMALS

Thoroughbred foals (n = 207), 171 age- and sex-matched maternal siblings.

METHODS

Medical records (2017-2020) were reviewed for signalment, limb(s) treated, location of the surgery, and any reported complications. Follow-up radiographs obtained for the yearling sale were assessed for abnormalities. Horses were matched to maternal siblings using an online database. Sales and racing performance data were compared between cohorts.

RESULTS

The average age at the time of surgery was 97 days. The treated limb was the left front in 52, right front in 31, both fronts in 119, unknown in 5. Three horses developed calcinosis circumscripta lesions adjacent to the physis, which were removed successfully. No radiographic abnormalities associated with the surgery site were detected on yearling prepurchase radiographs. There were no differences in sales and racing performance data between treated horses and maternal controls.

CONCLUSION

Hemiepiphysiodesis is a safe and effective treatment for metacarpophalangeal varus deformities in foals. No negative effect on sales or racing performance was identified.

CLINICAL SIGNIFICANCE

This technique avoids risks, costs, and the need for second surgery associated with an orthopedic implant. The surgeon should be aware of the potential for development of a calcinosis circumscripta lesion with this technique.

Transphyseal screw placement with and without hemicircumferential periosteal transection and elevation for correction of severe bilateral carpal varus deformities in an alpaca cria

CASE DESCRIPTION

A 2.5-month-old 17.5-kg female alpaca cria was presented for evaluation and treatment of severe bilateral carpal varus deformities.

CLINICAL FINDINGS

No lameness was evident at a walk, and neither carpal varus deformity could be corrected by means of manipulation. Radiography revealed severe varus of the left (27°) and right (21°) carpal regions. No additional conformational abnormalities were detected.

TREATMENT AND OUTCOME

A single 2.7-mm transphyseal cortical screw was placed in the distolateral aspect of the radius in each limb. On reexamination 8 weeks after screw placement, the left carpal varus deformity had corrected from 27° to 2.6°, and the left transphyseal screw was removed. The right carpal varus deformity had improved but was still present (18°), and hemicircumferential periosteal transection and elevation was performed on the mediodistal aspect of the right radius. Five weeks after the second surgery, the right carpal varus deformity had corrected to 2.4°, and the right transphyseal screw was removed. Six months after the second screw removal, both thoracic limbs remained straight, the cria had a normal gait, and the owner was happy with the cosmetic result.

CLINICAL RELEVANCE

Placement of a single transphyseal cortical screw with or without the addition of hemicircumferential periosteal transection and elevation can provide a favorable outcome in skeletally immature alpacas with severe carpal varus deformities.