The paws have many bones that are held in place by strong ligaments. Between each of the bones is a joint. A fracture-dislocation commonly involves a fracture of one or more small bones within the paw and/or tearing of ligaments that support the joints of the paw.
Cause of fracture-dislocation
In small breed dogs, landing on the hind limb from a fall or being stepped on is the most common cause of fracture-dislocations of the paw. In large breed dogs, substantial trauma is needed to cause this type of injury such as being hit by a car, getting the paw caught in a fence or getting the paw caught in a hole in the ground when running. Sometimes the injury will result in an open wound over the fracture-dislocation in which dirt and hair usually are driven into the tissues. This could potentially result in infection and delayed healing.
Signs and diagnosis
The clinical signs of a fracture-dislocation include non-weightbearing lameness, swelling and abnormal movement of the paw (instability). In order to determine the extent of the ligament damage to the paw, stress X-rays (pressure is applied to various joints in the paw during the X-ray) are done while the patient is under heavy sedation or full anesthesia. The information gathered from this study is critical to determine the type of surgical repair required. Prior to anesthesia and surgery, blood work is done in order to evaluate the health of the internal organs.
For most fracture-dislocations, screws are placed in the bone, and wire is tied around the screws to stabilize the disrupted joint(s). In some cases there is extensive damage or fractures of the bones in the paw and a fusion of the joint(s) is needed. This involves removing the cartilage from the joints, packing the affected joints with bone graft collected from the patient’s pelvis or shoulder and stabilizing the joint with screws or a plate and screws. If the fracture-dislocation is caused by a gunshot or other trauma that results in an open wound over the fracture site, an external fixator may be the treatment of choice. This apparatus consists of multiple pins that penetrate the skin and bone and are connected to external bars that run parallel to the bone.
Surgical repair of a fracture-luxation of the paw with metal implants allows for the best outcome. Most patients respond very well to the treatment with resolution of lameness. Arthritis likely will develop within the damaged joints, which may cause stiffness of the limb with heavy exercise, after weather changes or after napping. Medications can be prescribed to alleviate these signs. Uncommon complications include infection, failure of healing to take place, breakage of the metal plate or screws and cold sensitivity.
For more information on this subject, speak to the veterinarian who is treating your pet.