Disease of the cranial cruciate ligament is one of the most common orthopaedic conditions seen in dogs.
The condition involves a chronic degeneration of one of the major ligaments within the knee, or stifle joint.
The ligament progressively weakens and begins to tear. The signs associated with the early stages can be subtle such as mild intermittent lameness, stiffness rising or sitting with the limb extended. Eventually the already weakened ligament tears completely resulting in a much more severe lameness. The two bones of the joint, (the femur and tibia) are able to rock back and forth against one another causing instability, pain and inflammation.
Diagnosis can often be made by palpation or manipulation of the stifle. Some dogs will require sedation to be able to do this. X-rays will show signs of inflammation and osteoarthritis in the joint.
Treatment options
Conservative treatment for cruciate disease involves rest and anti-inflammatories. This is more likely to be effective in small dogs (less than 15kg) and those with early cruciate disease (i.e. before complete rupture). This treatment relies on the body forming scar tissue to stabilise the joint which takes time. Often surgery results in a quicker recovery. Some degree of osteoarthritis is inevitable in a damaged knee joint. Early stabilisation of the joint with surgery should reduce the progression of arthritis but does not reverse what is already there. If the joint is already very arthritic, conservative treatment may be advised as the dog would not be expected to regain normal function of the joint.
Conservative treatment is less likely to be effective in larger dogs so surgery is usually advised. Surgery involves removing any damaged cartilage (menisci) and stabilisation of the joint. Numerous surgical techniques have been described. The most commonly used techniques are the TPLO (tibial plateau levelling osteotomy) or extracapsular repair (lateral retinacular suture).
The extracapsular suture technique involves placing a synthetic suture around the outside of the joint to replicate the function of the torn ligament. It is a reliable technique in small/medium breed dogs but the risk of the suture stretching or failing increases as the size of the dog increases, which would result in persistent instability of the joint. This procedure can be performed at some of our branches.
More advanced techniques exist which change the geometry of the joint to counteract the forces that cause the instability. TPLO and TTA are the most common variants of this. A cut is made through the tibia (shin bone) and implants are used to secure it at an altered angle relative to the femur (thigh bone). These are very reliable techniques even in large/giant breed dogs. Most dogs are weight-bearing very soon after the surgery. The cost of these procedures are greater due to the complexity of the surgery and implant costs. We can perform an MMP (Modified Maquet Procedure) to stabilise the joint at Cinque Ports Vets. If you prefer to be referred to a specialist orthopaedic surgeon we are happy to arrange this.
All surgical techniques can provide good results but most specialist surgeons would agree that more advanced techniques offer a quicker and more reliable outcome for larger dogs. A prolonged period of restricted exercise is inevitable whether opting for conservative or surgical treatment.
Cruciate disease is a major problem and all of these options incur a degree of risk. The likelihood of successful treatment and a return to full exercise depends on various factors such as surgical technique, bodyweight, activity levels and duration of disease. A small proportion of dogs may suffer persistent lameness associated with cartilage damage and arthritis in the joint.
