Harriet, a four-month old female greyhound, was presented to the Oxford clinic with the suspicion of a dislocated toe. Greyhound puppies are reared on their mothers until around 10 weeks of age, before being weaned with their litter mates and managed in small paddocks with kennel shelter. This puppy was apparently normal at weaning and was thought to have dislocated her toe while “playing ” with her litter mates in the paddock.
At the time of presentation, the puppy was bright, alert and in good body condition, and no abnormalities with her cardinal signs were detected. The puppy was not lame at the walk, but the fifth toe of the right foreleg was pointing at a strange angle leading to a suspicion of a dislocated toe, and this can be a performance-limiting injury in racing greyhounds if not corrected and managed in a timely fashion.
Examination of the digit revealed an elevation of the third phalanx and abnormal weight distribution through the digital pad. There was suspicion of luxation of the joints between the first and second phalanx as well as the second and third phalanx, and possibly disruption of the deep digital flexor tendon.
The puppy was sedated and radiographs taken which, amazingly, revealed an absence of the second phalanx with reduced bone density of the third phalanx.
Diagnosis
Hemimelia – complete or partial absence of one or more bones. This can further be classified as either terminal hemimelia (a defect where all or some of the bones distal to a certain point are absent) or intercalary hemimelia (where bones above and below to a missing bone or bones are present), and this second was the case with Harriet.
Treatment
After discussion with the owner, it was decided to manage the puppy conservatively and monitor her closely for lameness and the development of a corn. If necessary, the toe could be amputated later if lameness was an issue.
Corns are unique to sight hounds and result from repeated mechanical trauma to a digital pad, usually due to anatomical reasons. Many treatments have been tried, but none gives consistent results. Surgical excision has been the best treatment to date; however, recurrence is seen in about 50% of cases after one year.
More recently, tendinotomy of the flexor tendons has been shown to give promising results. This involves cutting both flexor tendons on the palmar/plantar aspect of P1, with the protruding corn being pared to pad level. The tendinotomy results in a “dropped” toe with the nail protruding further than the neighbouring toes. When the limb is in extension, the toe will be elevated by about 30 degrees. The rationale of the procedure is to unload the pad and so reduce the mechanical trauma.
Currently, the conservative approach appears to be working. Harriet is still in the paddock with her mates with no lameness noted so far. The test will come when she reaches 12 months of age and begins more work. Currently the toe is almost in the position it would be following a tendinotomy, and hopefully she will not develop a corn as these are very painful for dogs.
Trish Moffat
Vetlife Oxford
