Written by Dr Michelle Trevan
The cruciate ligaments consist of two bands of fibrous tissue that cross over in the knee, like an X.
The cranial cruciate ligament (CCL) sits at the front of the knee and stops the lower part of the leg shifting forward, relative to the upper half of the leg. It also limits turning in of the lower leg and hyperextension of the knee.
Rupture of this CCL occurs commonly in dogs and can either be due to shearing forces from sudden twisting and turning movements (like jumping and chasing balls), or from deterioration of this ligament due to age (similar to an old rope fraying at the edges).
Complete rupture results in significant pain and dogs will often yelp and then hold their leg up completely. In some cases, only a partial rupture will occur. In these instances, dogs may just limp on the affected leg or “toe-tap” (place weight intermittently just to balance).
Once the ligament has ruptured, inflammation and instability result. This instability often leads to meniscus damage. The meniscus is a pad of cartilage within the knee that acts like a cushion. If nothing is done, the joint thickens, arthritis develops, the area becomes chronically painful and muscle wastage of the leg results.
Unfortunately, almost all dogs with a CCL injury will require surgery. The aims of surgery are to stabilise the knee, slow the progression of arthritis and return pain-free function of the leg.
The type of surgery chosen for your pet depends on a few factors such as size, activity, age and condition of your dog.
In larger dogs, we perform a technique called a Tibial Tuberosity Advancement (TTA) which changes the angle of the joint so that the knee doesn’t rely on the CCL for stability. In many cases, animals are walking on the leg the very next day!
In smaller patients, there is the option for a more traditional repair, commonly called the De Angelis procedure. This involves placing a heavy-duty piece of ligature outside of the joint capsule to basically recreate the function of the CCL.
Following any cruciate repair surgery, the post-operative period is just as important; dogs are on restricted activity for the first six to eight weeks and in most cases good function of the leg is returned within three months.
From there, it’s fingers crossed the same thing doesn’t happen to the other knee.