Orthopaedics & Spinal Surgery

The practice offers a range of orthopaedic and spinal procedures.

Treatment options for the loss of the anterior cruciate ligament support in the dog’s stifle

Conservative management

When the lameness is due to an instability and not pain in the joint, no drugs or surgery are necessary for management of the loss of the anterior cruciate ligament support. This approach works very successfully in small dogs under 10kg however with larger dogs, the return of function to normal use can take 6-12 months. Generally, the larger dogs suffer with loss of muscle in the affected leg and a large buildup of a restrictive degenerative joint remodelling. Progressive degenerative changes will result in a reduced range of flexion and extension with destruction of the cartilage cushions inside the joint (menisci).

Arthrex Tight Rope (Lateral Suture)

A bone tunnel is drilled in the thigh bone (femur) and the shin bone (tibia) and an artificial ligament is passed through the tunnels and tightened. This procedure does work successfully however there is a risk that the artificial ligament can be rejected by some dogs and need removing under a second general anaesthetic. The artificial ligament of fibre wire can break if the dog is allowed to be too active within the first 12 weeks after surgery. This procedure would involve:

Tibial Tuberosity Advancement (TTA)

The front top point of the shin bone (tuberosity) just below the knee joint (stifle ) is cut free and advanced anteriorly to alter the pull of the muscles over the knee joint so the instability within the knee joint does not occur under weight bearing. This procedure works well and is one of the most commonly performed surgical operations to correct the stifle instability. If the dog is not strictly controlled after surgery for a period of 12 weeks the titanium implants can fail or the shin bone (tibia) can fracture because it has been temporarily compromised by the original surgery. This procedure would involve:

Cora Based Levelling Osteotomy (CBLO)

This is the most recently developed surgical procedure to return stability to the stifle joint, offered as an alternative surgery to the TPLO because of the complications encountered with earlier surgical techniques. CBLO is the procedure I believe results in the best functional outcome in the long term with fewer complications compared with the other surgical options. The shin bone is cut below the knee joint and the section of bone under the floor of the stifle is rotated anteriorly to reduce the slope of the floor of the knee joint so as to stop the instability between the femur and the tibia as the dog bears weight on the leg. Strong bone plates and compression screws are used to achieve primary bone healing within 6 weeks after surgery. This technique is a very strong repair, and it is the best option for the very active or the very large dogs. This procedure would involve:

Tibial Plateau Levelling Osteotomy (TPLO)

The TPLO involves making a curved cuts into the tibia and rotating the top section to level the angle between the tibia and femur. The TPLO procedure has been replaced by the CBLO procedure and is therefore not performed at Willett House.

Summary

All the surgical procedures employed also include a video camera inspection of the knee joint (arthroscopy) and includes the surgical correction of any damage to the menisci (cartilage cushions within the joint). All procedures can at a later date, after the original surgery, suffer lameness due to damage to the cartilage cushions within the stifle joint (late meniscal pathology) which can require another  general anaesthetic and surgical procedure to remove the damaged meniscus. We have not observed lameness due to late meniscal damage to date with any of our Cora Based Levelling Osteotomy procedures however it is a reported complication, occurring following CBLO surgery. The absence of late meniscal pathology so far in our practice is potentially due to the detailed inspection of the menici with the camera inside the joint during the original surgical procedure with surgical correction of any damage found and the stronger stability achieved with Cora Based Levelling Osteotomies. The main cause of a loss of anterior cruciate ligament support within the dog’s stifle joint is a chronic degenerative arthritis which continues to progress in spite of all the above surgical options and will require medical management with various drugs as episodes of  lameness will occur due to the degenerative joint changes.