Abstract
Open splint bone fractures are at increased risk of osteomyelitis and/or sequestrum formation. Infection is not always restricted to bony structures but may also affect the surrounding ligamentous structures including the interosseous ligament. This case series describes 5 horses with infection of the metacarpal interosseus space, including the metacarpal interosseus ligament, as a complication of an open fracture of the fourth metacarpal bone. All described horses had been presented to the equine department, Vetsuisse Faculty, University of Zurich, between July 2017 and October 2021 and fulfilled the following criteria: radiographic diagnosis of an acute fracture of second metacarpal (MCII)/metatarsal bone (MTII) or the fourth metacarpal (MCIV)/metatarsal bone (MTIV); the fracture was classified as open because of a wound in the affected metacarpal/metatarsal region; the presence of radiographic signs of osteomyelitis in the interosseus metacarpal/ metatarsal space. Five horses fulfilled the inclusion criteria, and all had an open fracture of MCIV. Lameness at the walk varied from mild to severe. Wound secretion was present in 3 of the 5 horses. Radiography was done in all 5 cases and computed tomography was also used in 4 cases. Three different surgical treatments combined with antibiotics and nonsteroidal anti-inflammatory drugs were used: bone curettage, partial ostectomy and segmental ostectomy. All 5 cases made a complete recovery and returned to their intended use within 2.5 months to 2 years after surgery. In horses with persistent lameness and/or persistent wound secretion as a consequence of an open splint bone fracture, the adjacent metacarpal interosseus space should be assessed. Computed tomography appears superior to radiography for the presurgical staging of osteomyelitis because of its higher spatial and contrast resolution. The prognosis after extensive surgical and medical treatment appears to be good.
Attiger, Jeannette