Last year, we had the pleasure of giving a young goat a new lease of life by fitting a prosthetic foot, without which she would have faced a life of extreme debilitation or possible euthanasia if all other options had been exhausted.
Though the Royal Veterinary College (RVC)’s Equine Referral Hospital specialises in horses, we sometimes receive unusual non-equine cases. These have previously included goats, sheep, camelids (alpacas, llamas and guanaco) and oryx.
In this unusual goat prosthesis case, Thistle, a Nubian kid, was born with what was initially believed to be an angular/flexural deformity. An attempt was made to treat her with splints for a few weeks, but her condition did not improve. Radiographs were taken, and the referring veterinarian diagnosed an open fracture of the digits.
Referral to the RVC
Thistle was five weeks old when she was referred to the RVC’s Equine Referral Hospital for evaluation of the suspected fracture of her right front digits. On presentation, Thistle was bright and alert, with all vital parameters within normal limits. However, she was non-weight-bearing lame on her right forelimb and had a 4cm transverse wound proximal to the coronary band. The wound was full thickness and associated with moderate to severe instability at the digit level.
We carried out a computed tomography (CT) scan to further evaluate the fracture and determine possible treatment options and her prognosis. The CT scan identified chronic, open, comminuted, displaced, non-articular diaphyseal fractures of the phalanges (Figure 1). There was also complete loss of preservation and joint congruency of the distal interphalangeal joint, with intra-articular gas suggestive of associated septic arthritis.
Given the findings, repair of the fracture with internal or external fixation was not deemed possible as there was not enough bone left at the distal phalanges level. Other options were discussed with the owner, including possible euthanasia, amputation at the level of the radius and amputation at the level of the distal metacarpi with the hope of fitting a prosthesis on the distal limb.
Amputation and prosthesis
The owner elected to proceed with amputation at the level of the distal metacarpi, which was performed under general anaesthesia. A post-operative CT was performed to obtain exact measurements of the size and shape of the stump in order to help design and fabricate a 3D-printed prosthetic foot. Richard Bomphrey, professor of comparative biomechanics at the RVC Structure and Motion Lab, was consulted throughout the process, and he manufactured the prosthesis for Thistle.
Thistle recovered well from general anaesthesia, and the surgical site appeared dry following surgery – there was no discharge and only minimal swelling. She was discharged home six days later under the recommendation of keeping her in a small pen or paddock until suture removal after a fortnight. During that time, the bandage on Thistle’s right forelimb was changed every few days or whenever it became loose or soiled until she came back to the Equine Referral Hospital for suture removal three weeks later (Figure 2).
Thistle was then fitted with the new prosthetic limb under light sedation. The prosthesis resembles a ski boot with Velcro straps (Figure 3). It was 3D-printed with PLA filament, and a threaded bolt was inserted at the bottom to allow for adjustments in height as she grows (Figure 4). Several modifications were made to the design of the prosthesis over the course of her stay to make it more comfortable and easier for her to lie down in particular.
Both Thistle’s initial response to the prosthesis and progress post-operatively has been very encouraging. While she initially only used the prosthesis for a couple of steps, she was mostly weight-bearing on it and showing a more natural gait after a few days.
Rehabilitation
As Thistle had been walking on three legs since birth, she presented with severe muscle atrophy over her right forelimb, which needed to be built up gradually. She initially wore her prosthesis for just a few hours a day to get accustomed to it gently. This was then increased progressively over a few weeks and complemented by regular physiotherapy exercises once back home.
Thistle quickly became very attached to her new foot and was very reluctant to have it removed. However, this had to be balanced with risk of the site becoming tender if the prosthesis was left for prolonged periods of time.
Emily Cowderoy and Holly Smith, our small animal physiotherapy nurses, designed regular physiotherapy exercises to encourage Thistle to use the limb and develop her proprioception and musculature. She has also been having careful daily monitoring of the amputated limb to check for the formation of any pressure sores relating to the prosthesis as she grows.
How is everything going now?
Recent videos sent to us by the owner show that Thistle is using her prosthesis fully, and no complications were reported (Figure 5). We look forward to seeing Thistle again in the future as adjustments become necessary. Like human kids, she might need new shoes quite regularly!
Debbie Dale, Thistle’s owner, said: “I have always been very attached to having goats. Thistle was a twin and had some ligament issues from birth. We don’t know what caused the injury to her foot. Initial assessments were pointing towards having no option other than being put to sleep due to the extreme extent of the amputation she needed.
“I was convinced that due to her being so young and so well in every other way, we needed to explore prosthetics as an alternative. Luckily, my vet agreed and referred us to the RVC, where I met Mélanie and the team. Thistle’s mum was allowed to come to the appointment as Thistle was still feeding from her at the time. The RVC team thoroughly investigated our options – even contacting other vet specialists in America before we ended up having the 3D-printed prosthetic leg fitted.
“I am over the moon with Thistle’s progress. She’s back to her agile self – even bullying her brothers!”
