Research Update: Repairing fractures by using biodegradable bone plates

In this prospective clinical trial from Finland, 11 toy breeds with radial fractures were treated with single or stacked biodegradable polylactide plates, metal screws (AO 1.5- to 2-mm diameter mini screws), and lightweight external coaptation. The implants, which were specifically manufactured for this study, were 1 mm thick and without predrilled holes. The mean body weight of the dogs was 6.8 lb (3.1 kg), and the mean age was 21.6 months. The fractures were either mid-diaphyseal or distal radial/ulnar unilateral lesions that were repaired within three days of injury.

Most dogs were using the repaired limb two weeks after surgery, and external coaptation was removed at a mean of six weeks. Fracture healing occurred in 10 dogs, and complete radial healing was typically seen by nine to 12 weeks. One dog with two previous fractures at the same location fractured the antebrachium for the third time through a screw hole and was euthanized.

Two dogs had skin problems associated with the implant or external coaptation. No radiographic signs of osteopenia were observed under the plates, and only one plate was still palpable two years after surgery. Also, there was no evidence of foreign-body reaction to the dissolving plates over the years. The authors concluded that biodegradable plates are useful in treating fractures in toy breeds and that refinements in surgical technique and implant design will further enhance their acceptability.

Saikku-Bäckström A, Räihä JE, Välimaa T, et al. Repair of radial fractures in toy breed dogs with self-reinforced biodegradable bone plates, metal screws, and light-weight external coaptation. Vet Surg 2005;34:11-17.

COMMENTARY

The fracture of the radius and ulna in toy breeds is seen frequently in small-animal practice. While surgical repair with a small bone plate and screws or external skeletal fixation is often recommended, the bones are difficult to handle, and fracture healing can be prolonged. In this article, the authors describe biodegradable material that can be tailored to the bone and fracture. The material is of sufficient strength to promote healing while not being too stiff and thereby causing osteopenia. It will be interesting to note if the adjustments with the technique (i.e. using one or two stacked plates, the thickness of the plate, the need for external coaptation) and the cost of the material will make this another clinical option for veterinarians in surgical practices.

The information in "Research Updates" was provided by Veterinary Medicine Editorial Advisory Board member Joseph Harari, MS, DVM, DACVS, Veterinary Surgical Specialists, 21 E. Mission Ave., Spokane, WA 99202.

Joseph Harari, MS, DVM, DACVS