CORNS: AN UPDATE
Flexor tenotomy is now the accepted best treatment for corns and is performed in UK veterinary schools, veterinary practices and similarly around the world. In the 2.5 years since its inception and with my experience of over 200 surgeries, the technique has evolved into removing a short section of the superficial digital flexor tendon at the metacarpus/metatarsus. Technically this is called a tendonectomy.
Short and long term results continue to be excellent but a small number of dogs have a recurrence of the corn several months after the original successful surgery due to the tendon reconnecting. Fortunately these usually respond to repeat surgery. This is the reason for instigating the tendonectomy modification.
A NEW CLINICAL STUDY: A CALL FOR PARTICIPENTS
I am collaborating with Professor Eithne Comerford at the University of Liverpool with the aim of evaluating the reduction in pain at 12 weeks and 12 months post-operatively and then comparing your dog’s general life and well-being before and after surgery.
Prior to the surgery you will be asked to complete an online questionnaire and at your appointment photographs and videos will be taken. At 12 weeks and 12 months you will again be asked to fill in the questionnaire (it takes 5 minutes) and to take similar photographs and videos on your phone.
This study has now ethical approval but the entry requirements are strict. Qualifying candidates must have only one affected pad with no other orthopaedic problems. Only myself and Professor Comerford are allowed to perform the surgery and the questionnaire results will be evaluated independently. My surgery is based in Cheshire 10 minutes from the M6 and Professor Comerford is at the Veterinary School on the Wirral. If you would like to participate or require further information please contact me at firstname.lastname@example.org.
We need 140 cases for a meaningful statistical evaluation.
Patients with multiple corns or with other problems can of course be seen by myself outside the study.
FLEXOR TENOTOMY FOR THE TREATMENT OF CORNS
A corn is a hard circular area of thickened pad tissue that occurs in the toe pads of sight hounds and is found mainly in the pads of the central toes in the front limbs. It causes severe lameness especially when walking on hard uneven surfaces with the dog becoming reluctant to go for walks or play.
Corns are caused, as in humans, by repeated mechanical trauma or pressure on the pad. They are definitely not caused by a virus or by foreign body penetration. If that pressure is reduced the corn will grow out and disappear.
There are many different treatments that are advocated including ointments to soften, burn out or dissolve the corn; conservative management involving regular paring and protective foot ware, and surgery by either hulling or excising. Even if the corn has been completely removed it will recur in more than 50% of cases within a year because the mechanical pressure has not been addressed. This new treatment removes pressure on the pad by cutting the tendons under the toe (flexor tenotomy).
The original surgery involved cutting both the deep and superficial digital tendons under the toe through a small incision causing the toe to flatten and the nail to stick out losing contact with the ground. If the dog is lying on its side with the leg extended the toe will be elevated by about 30 degrees.
This has now been modified by cutting only the superficial digital flexor tendon (SDFT) just above the foot. The nail again sticks forward but remaining in contact with the ground and the toe is not completely flattened. In both procedures the corn is not pared or removed.
Although the results of both procedures are comparable SDF tenotomy is less likely to cause concussive pain under the toe on rough ground and aesthetically it looks better.
Recovery is rapid and by seven days post surgery most clients have reported a great improvement in both lameness and demeanour. These dogs want to play and exercise!
By eight weeks almost all corns have grown out leaving a normal soft pad with no or slight
Frequently asked questions:
1. What is the recovery period from the surgery?
The dressings are removed after 24 hours and it is recommended that there is lead exercise for a further 10 days and then free exercise. Lameness is dramatically reduced by day 2.
2. My dog has a corn on a central toe but the adjacent toe has been amputated. Is tenotomy a suitable procedure in this case?
Yes with a SDF tenotomy. A full tenotomy requires the support of adjacent digits to prevent contact of the skin under the toe with the ground and so is not suitable.
3. By increasing the weight distribution onto the other pads is there a further risk of subsequent corn development?
Some dogs have a genetic tendency to develop multiple corns and at present there is no evidence to support this assumption. Possibly there is an increased risk of one developing in the same foot but there are not enough cases to determine this.
4. Will the corn grow back in the future?
This is highly unlikely.
5. Can more than one foot have the surgery in the same session?
Yes with no adverse effects on the patient. All four feet have had tenotomies in one session.
Results of the completed study
91 dogs with 149 corns:
Over the course of the study 39 dogs had more than one corn (43%)
Whippet = 17 Greyhound = 70 Lurcher = 4
Full tenotomy results:
• 86 dogs with 113 corns
• At 8 weeks 12 dogs had slight lameness and 54 dogs had no lameness
SDF tenotomy results:
• 27 dogs with 37 corns
• At 8 weeks 6 dogs had slight lameness and 20 dogs had no lameness
• Overall 97% dogs had slight or no lameness.
12 month follow up on 30 dogs
• 1 dog had moderate lameness, six dogs had slight lameness and 23 dogs had no lameness
Owner satisfaction: all very satisfied with the outcome reporting that the dogs were much happier and more willing to exercise.
• All corns had grown out
• Racing dogs returned to racing.