Non-surgical treatment including bandaging and physiotherapy can be an option for some animals with developmental hyperextension or animals with low-grade sprain injuries.
How can I tell if my dog has carpal hyperextension?
There are three common forms of injury to the carpus:
(1) The first form affects puppies and involves an abnormality in the development in the ligaments supporting the joint. Affected puppies walk with excessive extension of the carpus (with a gait more like a bear’s than a dog’s). Both wrists tend to be affected in puppies with this condition and in some extreme cases the hock joints (ankles) in the hind limbs can also be affected. Puppies that have ligament laxity and subsequent hyperextension of the carpus as a result of prolonged immobilization in a bandage are only affected on the bandaged leg.
(2) The second form of injury to the carpus is the result of trauma. There are varying degrees of sprain injury affecting the carpus. The amount of lameness and swelling depends on the severity of trauma. Some dogs will have an obvious postural abnormality with inappropriate deviation of the affected joint.
(3) The third form of carpal injury is degenerative hyperextension of the wrists. This problem affects older dogs and is especially common in Collie breeds. There is a tendency for one or both wrists to gradually sink until they completely collapse.
Some problems affecting the wrist joint also affect other joints and are in the group of polyarthritides. These are the animal equivalent of rheumatoid arthritis and can affect the joints of the fore and hind limbs of dogs and cats.
What diagnostic tests are performed to assess carpal problems?
Physical examination can give us a good idea of the nature of the problem. We may perform special stressed radiographic tests to help us assess which ligamentous structures are damaged. In animals where broken bones are suspected but are not seen on the plain radiographs, we frequently recommend a CT scan. Occasionally, MRI can provide useful additional information.
What are the usual treatment options?
The best treatment for a carpal problem depends on the underlying cause. Non-surgical treatment including bandaging and physiotherapy can be an option for some animals with developmental hyperextension or animals with low-grade sprain injuries. Recently, customized carpal supports have been developed that may allow daily use and may be easily put on and taken off without causing pressure sores due to prolonged application. Animals with broken bones are either treated by surgical repair of the broken bone(s) or by (partial) fusion of the carpal joint.
Severe high-grade sprain injuries and most forms of degenerative hyperextension are usually treated by fusion of the affected joint. This procedure is called pan-carpal arthrodesis. We have led the field in the development of new technologies of internal and external skeletal fixation in this arena.
If a diagnosis of immune-mediated polyarthritis is made, the treatment is usually medical. Rarely, some dogs and cats require fusion of their carpal joints if they are affected by severe rheumatoid arthritis.