Jock is a very excitable 9-month old Border Collie cross farm dog, who fell off a bike recently and fractured his hind leg. As usual, this fracture presented its own unique challenges for us to deal with.
Firstly, the tibia was broken into more than two fragments. This is a called a comminuted fracture and makes it significantly more difficult to stabilise.
Secondly, the fracture was very far down the leg, close to the hock (ankle) joint. Now as you all know from previous posts here, this makes it tricky as there is very little bone stock in the lower fragment to attach anything to.
On Jock’s side, he is a healthy young dog. This means bone healing is likely to be much faster than an older dog. This is important in the lower tibia, which is an area of the body notorious for poor bone healing due to limited soft tissue coverage and poor blood supply.
The repair technique chosen was one of my favourites, the plate-rod. This involves putting a steel pin down the inside of the bone from the stifle (knee) joint, which gets the stifle and hock joints in the right alignment with each other, pushes them the right distance apart, and is very strong against bending forces.
Then a plate and screws are applied to the outside of the bone. This prevents the fragments from rotating around the pin or sliding up and down the pin.
The plate-rod combination is one of the strongest available and provides very rigid stability immediately after surgery.
To cope with the three fragments, one of the fragments was lagged to another. This involves drilling a glide hole through one fragment, and a threaded hole through the other, so when the screw is tightened it pulls the two fragments together. What made this one a little unusual is that lagged screw was one of the plate screws.
This meant I still needed two screws in the lower fragment for stability, which was going to get very crowded given the lack of bone available. And that’s why I chose a slightly smaller screw and plate size and then angled the screws in the plate up and away from the joint to avoid both the joint surface and the growth plate, which is where the bone will grow from.
Hitting exactly the right spot with a drill is difficult, since even though the x-ray shows the bones very clearly, the surgical view is nothing like that, since there is soft tissue covering everything. We use tiny needles placed at strategic points in the bones and joints, which are measured on the x-ray pre-surgery, and then measure drill holes and angles from these during the operation.
So, enough of the details, the surgery went really well and Jock was up and walking on the leg the next day.
At 6 weeks, the bone has completely healed, the growth plates were not affected so the leg has grown to normal length, and Jock is not lame at all.
He will be making a return to full work over the next 2 weeks. Nice ending to a story, and great to see Jock this week bouncing around and raring to get back out there again.