Disease of the cranial cruciate ligament is a common cause of lameness. We expect the majority of our cases to have a very favourable outcome following surgical management of this debilitating condition.
Tibial plateau leveling osteotomy (TPLO) is our most frequently performed surgery for this condition but there are other options available including Cranial Closing Wedge Ostectomy (CCWO), Tibial Tuberosity Advancement (TTA) and Ligament Substitute such as Lateral Fabellotibial Suture.
In recent studies, this procedure has been shown to be the technique most likely to return maximal limb function and as such is our favoured technique. The TPLO procedure does not rely on the presence of the ligament but instead changes the forces in the joint to create a more stable ‘platform’ when the dog is weight bearing on the leg. A semi-circular cut is made in the top of the tibia (shin bone) and the top section of bone is ‘levelled’ to improve stability in the joint. The cut bone is stabilised with a bone plate and screws. Once the bone is healed the procedure is complete. Although the bone is cut, this is well tolerated procedure with many dogs weight bearing on the leg within 48-hours of surgery.
Placement of a suture (lateral extracapsular suture or fabellotibial suture) around the outside of the joint (under the skin) is a technique that has been used for many years. There are many variations: Nylon is often used as the substitute ligament material, secured by knotting or with a metallic crimp but the suture stretches or breaks over time and the patient can return to the pre-operative status in the early phases of recovery. Recently, more robust materials have been developed (Fiberwire®) which do not fatigue in the same way. The TightRope® technique utilises Fiberwire® which has been shown to have some encouraging outcomes. These techniques may have a better outcome where the injury relates to trauma, as the knee was a ‘normal’ joint prior to injury. With genuine traumatic cranial cruciate ligament ruptures other ligaments may be affected and can be managed using the same ligament substitute material – we call this a multi-ligamentous or a global knee injury.
This technique also levels the top section of the tibia in a similar way to TPLO but by removing a wedge of bone rather than using a curved cut. This was the predecessor surgery to TPLO and is occasionally used in some patients especially some small breeds. The bone is again stabilised with a bone plate and screws.
This technique also uses a cut in the top of the tibia (shin bone) but in this case the front of the knee is ‘pushed’ forwards to change the forces in the knee. The recent literature does not demonstrate the same outcomes as with TPLO. This technique also has a higher incidence of cartilage injury after surgery (late meniscal injury) compared to TPLO. Very few patients are considered suitable candidates for this procedure in our clinic.
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