Cruciate ligament disease in the dog

Background

There are two cruciate ligaments in the knee (or ‘stifle’ as we call it in dogs). Cruciate disease (affecting the cranial cruciate ligament) is one of the most common orthopaedic conditions seen in dogs. In people cruciate ligament ruptures are typically seen as acute sporting injuries in footballers and skiers for example. In dogs, it is a little different and presents as a more chronic degenerative condition. The ligament degenerates and gets weaker with time, and at some point, will start to tear.  

cruciate image 1The signs associated with the initial stages of the condition can be subtle and may be missed –signs such as stiffness on rising from rest and mild, occasional lameness. As the ligament continues to tear the signs may become more obvious but it is not uncommon for owners to first realise their dog has a problem when the already weakened ligament finally tears completely, often during relatively normal activity. At this stage the stifle will be unstable –the two bones of the stifle (the tibia and femur) will rock back and forth during walking. This instability will lead to pain, development of osteoarthritis and potential for damage to the menisci (cartilage ‘shock absorbers’ of the knee), which can cause significant lameness and discomfort.

Diagnosis

The diagnosis is often made on palpation/manipulation of the stifle, although in some dogs this may require sedation. X-rays will show signs of osteoarthritis (OA or ‘arthritis’). Early cases may be less easy to diagnose, sometimes requiring exploratory surgery/arthroscopy to visually examine the cruciate ligament.

Treatment

Some small dogs (less than 15kg) may do well with a period of rest and anti-inflammatories alone, although surgery is generally considered to offer a quicker and more reliable recovery. Larger dogs are less likely to do well without surgery and so surgery is always advised.  Numerous stabilisation techniques have been described. The most successful techniques involve placing a restraining suture around the outside of the joint to try to replicate the function of the torn ligament (known as extracapsular stabilisation) or changing the geometry of the tibia to counteract the forces that are responsible for the instability.

Cruciate xray 1

We are advising to treat your pet’s cranial cruciate ligament failure surgically using a geometry changing technique known as the Modified Maquet Procedure (MMP). The operation is based on a technique developed almost 50 years ago for use in human knees by Dr Maquet, a Belgian orthopaedic surgeon. The operation works by redirecting the force generated by the large quadriceps muscles to compensate for the failed cruciate ligament. This is achieved by cutting free, and moving forward, the part of the tibia (the tibial tuberosity) attached to the quadriceps muscle. The bone cut is called an osteotomy and the osteotomy is stabilised using a modern orthopaedic implant material called Orthofoam. The porous titanium Orthofoam promotes remarkably rapid bone ingrowth and healing and this is key to the reduced convalescence and minimal pain seen with MMP surgery.

Successful recovery after knee surgery, no matter which procedure has been used, requires a period of controlled activity. Compared to other procedures, MMP causes less discomfort and while a comfortable, painfree patient is obviously a good thing, many dogs are tempted to use the operated leg too much, too soon. No matter how comfortable and confident your pet is feeling in the days after their MMP operation, it is absolutely essential that running, jumping, and general “rough and tumble” with other pets is avoided for the first 6 weeks or so. The bone must be given time to heal adequately and too much strain placed on the osteotomy too early can result in stress fracture or implant failure and while this is rarely catastrophic, the ensuing complication may be painful and will certainly delay the recovery. The operation works by redirecting the force generated by the large quadriceps muscles to compensate for the failed cruciate ligament. This is achieved by cutting free, and moving forward, the part of the tibia (the tibial tuberosity) attached to the quadriceps muscle. The bone cut is called an osteotomy and the osteotomy is stabilised using a modern orthopaedic implant material called Orthofoam. The porous titanium Orthofoam promotes remarkably rapid bone ingrowth and healing and this is key to the reduced convalescence and minimal pain seen with MMP surgery.