Medial malleolus fragmentation following talocalcaneal arthrodesis by a dorsomedial approach in a horse

A 16-year-old, Quarter Horse mare was presented for a 3/5 right hind lameness associated with osteoarthritis of the talocalcaneal joint (TCLJ). Positron emission tomography (PET) and computed tomography (CT) demonstrated marked increased uptake of 18F-sodium fluoride and bone remodeling at the medial facet of the TCLJ, respectively. Under general anesthesia 2 cortical screws (4.5 and 5.5 mm) were placed in neutral fashion via an arthrotomy from dorsomedial to plantaromedial through the medial facet of the TCLJ followed by copious lavage of the tarsocrural joint. Eight weeks after surgery, observable effusion of the tarsocrural joint was present and lameness had worsened. Radiographic examination revealed a fragmented medial malleolus of the tibia, likely secondary to repetitive trauma of the screw heads during tarsal flexion. Repeated CT showed partial fusion of the TCLJ. Both screws were removed and the tarsocrural joint was thoroughly lavaged arthroscopically. At a 20-month recheck the lameness had not improved, and ultrasound examination revealed severe thickening of the TCLJ capsule. Recheck examination 48 mo after surgery showed complete fusion of the TCLJ and resolution of the lameness.

Automated summary

Surgical treatment for osteoarthritis of the talocalcaneal joint in a 16-year-old Quarter Horse mare led to initial complications but ultimately resulted in complete fusion of the joint and resolution of lameness after 48 months of rehabilitation.