Fractures of the Patella in Horses
Fractures of the patella in horses usually result from direct trauma, most commonly when a horse is kicked by another horse or hits a fixed obstacle while jumping. The prognosis depends on the fracture configuration:
Sagittal fractures of the medial pole of the patella are the most common patellar fractures. They are usually intra-articular and involve the attachment of the parapatellar fibrocartilage of the medial patellar ligament. Complete sagittal fractures might be more amenable to internal fixation than those of transverse orientation, because there is less distractive force.
Complete horizontal fractures are rare but considered serious injuries because of fragment distraction due to the massive pull of the extensor muscles.
Fracture of the patella usually results initially in marked lameness, with swelling and edema over the patella and effusion of the femoropatellar joint. In less severe or nonarticular fractures, lameness might improve within a few days.
Diagnosis of patellar fracture in horses is confirmed by radiography. Standard radiographic projections of the stifle, together with a cranioproximal-craniodistal oblique (skyline) projection of the patella, are used to define the fracture.
Options for treating fractures of the patella in horses depend on the fracture configuration:
Small, nondisplaced, nonarticular fractures may be treated conservatively with stable rest for 6–8 weeks and have a good prognosis for return to athletic function.
Articular fractures of the medial pole of the patella can be removed arthroscopically or via arthrotomy; they also have a good prognosis.
Larger, midbody sagittal or horizontal fractures require repair by internal fixation. These injuries carry a risk of catastrophic breakdown during recovery from anesthesia, but the outcome can be favorable.
Fractures of the Tibial Tuberosity in Horses
Fractures of the tibial tuberosity in horses are not uncommon. Minimal soft tissue covers this area, and fractures usually result from direct trauma. Fracture configuration ranges from small fragments off the cranial proximal part of the tuberosity to large fractures of the whole tuberosity extending into the femorotibial joints.
Tibial tuberosity fracture usually results initially in marked lameness, with localized swelling and edema. Lameness often improves within a few days. Diagnosis is confirmed by radiography.
Small and nondisplaced fractures might heal with conservative treatment. Stable rest for 6–8 weeks is advised. During the first 2–3 weeks, the horse should be prevented from lying down by tying or using slings to prevent fragment displacement. Larger intra-articular fractures should be repaired by internal fixation.
Horses with fractures of the tibial tuberosity generally have a good prognosis for return to athletic function if the injury is appropriately managed.
Fractures of the Femoral Condyles and Femoral Trochlear Ridges in Horses
Fracture of the femoral condyles is usually the result of direct trauma. Large, intra-articular, displaced fractures in adult horses are catastrophic, and these horses have a grave prognosis.
Traumatic fragmentation of the femoral condyles or trochlear ridges can also occur. Such injuries usually result in acute-onset, moderate to severe lameness with joint effusion.
Diagnosis of femoral condylar and femoral trochlear ridge fractures is confirmed by radiography.
Treatment involves surgical removal of the fracture fragments to prevent the development of osteoarthritis. Surgery is usually arthroscopic, but arthrotomy might be required. The prognosis depends on the fragment size and the ability to remove or adequately reduce it, as well as the extent of concurrent cartilage damage.
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Also see pet owner content regarding disorders of the stifle in horses.
