Cruciate
About the Cranial Cruciate Ligament
The cranial cruciate ligament, situated within the stifle (knee joint), connects the tibia (shin bone) to the femur (thigh bone) and serves a mechanical function. It stabilizes the joint during flexion and extension, preventing forward movement of the tibia (cranial drawer movement) and limiting rotation and hyperextension.
When bodyweight compresses the femur and tibia, the absence of a healthy cranial cruciate ligament results in rolling between the bones, causing forward tibia movement and backward femur rolling.
About the Menisci
The menisci, two fibro-cartilage discs within the stifle joint, act as shock absorbers. They are positioned medially and laterally between the femur and tibia.
Rupture of the Cranial Cruciate Ligament
Often stemming from slow ligament degeneration, a ruptured cranial cruciate ligament leads to joint instability, lameness, pain, and potential meniscal injuries. The loss of the ligament mechanical function results in a cranial drawer movement during exercise, causing pain and increasing the risk of meniscal injury. The absence of mechanical function also leads to the tibia pushing forward during weight-bearing, contributing to osteoarthritis.
Cruciate Treatment
Medical treatment
Non-surgical, medical treatment may be suitable for higher-risk patients or old, inactive patients weighing less than 15 kg. This includes anti-inflammatory medication, a strict diet, and controlled exercise. Physiotherapy/hydrotherapy can aid recovery, but joint stability is crucial to prevent osteoarthritis progression. This method is not recommended for young or active patients.
Surgical Treatment
Various surgical techniques aim to stabilize the stifle joint.
Common procedures involve modifying joint biomechanics by cutting the top of the tibia.
Tibial Plateau Level Osteotomy (TPLO)
The aim of this surgery is to stabilize the stifle joint by modifying its biomechanics.
A flattening of the tibial plateau is achieved by making a circular incision on the top of the tibia (osteotomy). The top bony fragment is then rotated and fixed with plates and screws. The amount of rotation will be measured using high-quality radiographic images taken prior to the surgery. We always use a high-quality locking plate system, which helps reduce postoperative complications.
Once the slope is no longer present, the knee will no longer require the cranial cruciate ligament to stabilize the leg during weight-bearing.
A meniscus inspection is always performed as a routine procedure before executing a bone cut. Meniscus treatment is undertaken in case of additional injury.
Closing Wedge Osteotoy (CWO)
The aim and the mechanic of this procedure are exactly the same as the TPLO. The main difference is that a wedge of bone is removed from the tibia to achieve a flat tibial plateau. This will lead to the shortening of the leg.
Tibial Tuberosity Advancment (TTA)
The aim of the surgery is to modify the biomechanics of the joint making a vertical straight cut on the top and front of the tibia. The tibial front fragment is pulled forward and secured with a metallic cage, plate, and screws. The goal of the advancement of the tibial crest is to modify the angle between the patellar tendon and tibial plateau (top of the tibia). The stability of the joint is achieved when the tibial plateau has an angle of 90 degrees with the patellar tendon.
Complications and Why We Prefer TPLO
The complication rate is generally low for all procedures. Infections are common but manageable with antibiotics. Deep infections following TPLO may require plate removal, whereas Lateral Fabella Suture and TTA may involve more complex procedures. Late meniscal injuries are possible, with varying rates for each surgery type. TPLO, despite its complexity, exhibits a lower complication rate and easier infection management. Osteoarthritis progression is minimal compared to untreated joints.
Osteoarthritis Progression
While the goal is joint stability and a lameness-free patient, all surgical methods result in minimal osteoarthritis progression. Surgical treatment significantly reduces osteoarthritis compared to untreated joints.