Correction of Radial Dysgenesis Deformity Using Hinged External Fixator and Ulnocarpal Arthrodesis

Case Report: Radial longitudinal deficiency and other deformities leading to the inability of the radius to be a weight bearing structure are rare but can cause significant functional limb deformities in dogs and cats. These cases are often treated with amputation or other complex surgical techniques, with high complication rates and variable return to limb function. The objective of this case study was to document a successful method useful for treating radial dysgenesis, in which the radius cannot be the weight bearing structure. A 5-month-old dog was presented with a 5/5 right forelimb lameness with severe varus and supination deformity at the level of the carpus. The radiographic assessment of the limb showed a type II radial longitudinal deficiency with ectrodactyly, severe proximal and distal radial head luxation, and hypogenesis of multiple carpal bones. A hinged, circular external skeletal fixator construct was placed for distraction histogenesis of the flexor tendons and medial ligaments prior to ulnocarpal arthrodesis four weeks after fixator removal. Previous techniques struggled with postoperative rigid flexion of the phalanges due to acute correction with concurrent soft tissue flexor contracture; a complication not seen in this case. The dog had functional use of the limb at long-term follow-up (1,555 days) with just a 2/5 right forelimb lameness, radiographic elbow arthritis of low clinical impact, and the ability to run comfortably without chronic pain medication. This is a technique that was applied successfully to this radial dysgenesis deformity with good long-term outcome and should be considered for similar deformities.

Acknowledgments: The authors have no financial disclosures or conflicts of interest related to this project.

Publication History

Article published online:
11 September 2023