What is Fracture of the Patella?
Due to considerable advances in equine orthopedics, long-held beliefs that horses cannot recover from musculoskeletal injuries are outmoded. A fracture, particularly to a weight-bearing joint such as the knee, was long perceived as particularly unsurmountable. Fortunately, developments in veterinary orthopedic medicine such as arthroscopic surgery enable horses to recover from previously life-ending injuries such as a fractured stifle, which is the equine equivalent to the human knee. Internal fixation (the use of plates and screws), for example, enables an injured horse to stand on a fracture while it heals, making previously life-threatening breaks treatable.
Found in the hindquarters of the horse, the stifle is a large, complex joint that comprises four bones, one being the patella. The patella, commonly known as the knee cap, in the horse comprises an osseous (bony) portion and a fibrocartilage (narrow clefts containing the cartilage cells) portion. The patella is attached to the tibia by three ligaments, and serves to provide protection to the knee joint.
As with a human, the horse’s patella is a freestanding bone meant to cleanly slide between the femur and the tibia. When the patella fractures, the entire joint is unable to provide the stability that a horse needs to even stand in place. The horse may become lame on impact, and become reluctant (due to pain) to try and bear its weight. Immediate veterinary care will be needed to address the fracture, treat the pain, and determine if the horse will require surgery.
Due to considerable advances in equine orthopedics, a fracture of the patella is no longer considered a life-ending injury for all horses.
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Symptoms of Fracture of the Patella in Horses
- Inability to stand or walk
- Limping or altered gait
- Sudden lameness
- Altered appearance to the leg (bone or bony pieces may be visible to the naked eye)
- Unwillingness orresistance to exercise
Patellar fractures are described in veterinary terms as articular and nonarticular. The exact type of fracture will be determined by ligament involvement, location of fracture, and configuration (for example, horizontal or longitudinal).
Causes of Fracture of the Patella in Horses
- Repetitive stress in performance horses
- Impact with fence or other hard surface
- Kick from another horse or self-imposed
- Falls on rocky, craggy or uneven surfaces
- Jumping at high speeds
Diagnosis of Fracture of the Patella in Horses
Early diagnosis and treatment are critical after a fracture to the patella. The horse’s limb will quickly and significantly swell following the break, and the horse may be unable, or resistant, to bear its own weight. The veterinarian will observe the horse’s behavior in response to the injury, and look for lameness as a sign of pain.
The fracture may be visible during the initial manual examination, especially if bone or bone fragments are visible. It is important to inform the veterinarian if a popping sound or crack was audible at the time of injury. A fracture will require radiographic confirmation. Additionally, an ultrasound can confirm ligament involvement.
Treatment of Fracture of the Patella in Horses
In the case of a fractured patella, surgery can often be done arthroscopically. The surgeon will focus on removing fragments of the patella. In the best-case scenario, there is enough intact patella that your horse can slowly return to an active life.
Clearly, surgery is necessary in most cases. The horse is placed under general anesthesia during surgery, and will receive medication (systemic and local) for inflammation and pain. Prognosis will depend on the age and health of your horse and the extent of the fracture. Documentation states that some horses with a fracture of the patella have been known to have a positive recovery after an extensive period of stall rest, but again, age will have a factor in the prognosis, as will the size and personality traits of the horse (whether he will be a suitable candidate for extended rest and confinement).
Recovery of Fracture of the Patella in Horses
All breaks have varying prognoses for recovery. The recovery process is expensive, slow-going, and for some, will require extensive, long-term care.
With the best possible care, many fractures heal during four to six months of rest, though it takes at least a year for the horse to reach its potential. During this time, there will be many risks for complications, so routine veterinary visits will be necessary. Some horses experience anxiety while healing; any falls or frenetic movements may re-injure the horse, or cause an entirely new injury. Medications for anxiety may be administered.