Cranial cruciate ligament disease is a common orthopaedic issue in dogs. But what is it? And how is it treated? We’re here to answer all your most frequently asked questions about this frequently diagnosed condition, so read on to find out more!
What are the cruciate ligaments?
The cruciate ligaments are two important structures found in each of your dog’s knee joints (stifles). The knee joint has no interlocking bones and is instead held together and given stability by these ligaments. These also allow it to move backwards and forwards like a hinge.
The word cruciate means ‘to cross over’ and these two ligaments do exactly that, crossing each other within your pet’s knee joint. The cranial cruciate ligament (CrCL) is more prone to damage than the caudal cruciate ligament (CaCL). So, when your pet has a problem with their cruciate ligament, it is usually the cranial one that is more likely to be affected.
What is cranial cruciate ligament disease?
Cranial cruciate ligament disease is a term that describes damage or wear and tear to the cranial cruciate ligament. It is also referred to as just cruciate ligament disease or, more rarely, a cruciate rupture (although this is now considered less accurate).
It is possible for dogs to suddenly break their ligament through excessive trauma, like a road traffic accident. However, for most dogs (and unlike humans), the cruciate ligament usually becomes damaged progressively over a long period of time, which causes associated pain and inflammation.
The ligament slowly frays and degrades (like a rope), gradually weakening to the point where it finally ruptures. The joint loses stability, which further contributes to lameness. The thigh bone and the shin bone no longer move correctly in relation to each other, causing more trauma within the joint.
Other structures in the knee can become damaged, including the menisci. These are two ‘C’ shaped pieces of cartilage that sit on either side of the knee. They support the bones of the knee and behave like shock absorbers. When the menisci are damaged, this further adds to loss of joint function, contributing to yet more pain and inflammation. Osteoarthritis can also occur in these diseased joints, which will progress and worsen over time, especially if the condition is left untreated.
Why does cruciate ligament disease occur?
Currently, we do not know for sure what causes degeneration to occur in the ligament, but it is thought to have a genetic component. This means certain breeds are more likely to be affected by cruciate ligament disease, including:
- Labrador Retrievers
- Boxers
- West Highland White Terriers
- Newfoundlands
However, any breed of dog could develop the condition.
Other risk factors include:
- Age – middle-aged dogs are more susceptible.
- Obesity – being overweight increases abnormal pressures on joints.
- Conformation of the joint – uneven pressure and forces in the joint can cause ligament
degeneration. - Hormonal factors – dogs that are neutered before skeletal maturity seem to be at higher risk
What are the symptoms of cranial cruciate disease?
Lameness is the most common sign of cruciate ligament injury or disease. This can be a mild, ongoing limp, getting worse over time. It may be made more obvious by exercise. The limp can be intermittent in nature. Lameness can also appear suddenly in some dogs, usually when there has been a traumatic injury or if the ligament rupture finally occurs after a period of unnoticed chronic disease.
Sometimes both knees are affected, so the lameness can be hard to spot as the dog doesn’t favour one leg over the other. However, they may struggle to stand or move differently to usual when walking.
As well as lameness, other signs of cranial cruciate disease may include:
- General stiffness of the affected leg
- Pain when the leg is touched or examined
- Swelling of the affected leg
- Changes in the way they walk
- Sitting in awkward positions with the affected leg held out
- Struggling to jump onto furniture or into a car
- When standing still, the dog may be toe touching with the affected leg (not putting their weight on it fully)
What should I do if my pet’s showing signs of cruciate ligament disease?
Book an appointment to see us!
If your pet is showing symptoms like lameness, stiffness, and changes in their mobility, then they will be in pain, even if they still appear to be bright and eating ok.
We will start by performing a physical examination. This can help us to check the degree of lameness your pet is experiencing and to look for signs like knee swelling, muscle wastage, and instability in the joint. We will also discuss your pet’s symptoms and check other parameters like their heart rate and temperature. Depending on the vet’s findings, they may suggest diagnostic imaging.
Diagnostic imaging
In most cases, radiographs (X-rays) are the next step in diagnosing and assessing the degree of cruciate ligament disease.
Your dog will need to have an anaesthetic or heavy sedation to allow images to be taken of their affected limb. Two views of the leg are taken, so that different angles of the knee joint are captured. Often, we will image the ‘good’ leg as well as the lame one. It can be useful to compare the two as well as to check there are no issues here too. Sometimes our vets will take other images while your
pet is asleep too, which ensures there are no other issues present, such as hip dysplasia.
The images taken will help to diagnose the condition, but will also allow for treatment planning, especially if measurements need to be made for surgical implants.
CT scans may also be useful in some cases, especially if classic signs of disease are not present on radiographs.
Exploratory surgery
Occasionally, exploratory surgery may be needed to explore the joint and assess the state of the ligament and menisci. This can be done by opening up the joint or by a procedure called arthroscopy, where a small camera is inserted into it to look around for signs of disease. Sometimes it’s possible to assess the joint and fix the problem under the same general anaesthetic, but other times, surgery will need to be planned for a later date.
What are the treatment options for cranial cruciate ligament disease?
Treatment falls into two categories:
Surgical management
In most cases, surgery is required to treat cranial cruciate ligament disease. There are various surgeries available to treat cruciate ligament disease, but all will require a general anaesthetic and a sterile surgical technique. These surgeries can be split into two broad groups – those that attempt to replace or replicate the damaged ligament, and those that remove the need for the ligament altogether by altering the forces acting on the knee joint.
Ligament replication techniques
Synthetic materials can be used in cruciate ligament surgery to stabilise the joint. The lateral suture (also called fabella-tibial suture) method involves exploring the knee joint and removing any of the damaged ligament and cartilage. The joint is then stabilised with synthetic material, which recreates the action of the damaged cruciate ligament. This procedure is less suitable for large or athletic dogs.
Techniques that cause the cruciate ligament to become redundant
These types of surgery change the mechanics of the knee by altering its angles and forces so that the cruciate ligament is no longer required for the joint to remain stable. This involves reshaping the top of the shin bone (the tibia) by cutting the bone and changing the angle, then reattaching it in a new position. During surgery, any damaged ligament is also removed, and the menisci are also examined and removed if damaged.
The following are examples of this type of surgery:
- Tibial plateau levelling osteotomy (TPLO)
- Tibial tuberosity advancement (TTA), including the modified Maquet Procedure (MMP)
- Cranial Closing Wedge Ostectomy (CCWO)
Non-surgical management
This is not commonly recommended unless there are considerable risks associated with a general anaesthetic for your dog or if there are financial constraints.
Non-surgical management options are not often advised because the condition will continue to get worse over time. It is a progressive, degenerative disease with irreversible arthritic change occurring in the affected knee joint.
Your dog’s weight also needs to be taken into consideration. Dogs heavier than 15kg have a very low chance of their symptoms resolving with non-surgical treatment. Dogs that weigh less than 15kg stand a better chance; however, it is a time-consuming and lengthy process.
Non-surgical management options include the following:
- management of weight
- physiotherapy
- control of exercise
- pain medication
What does postoperative care involve?
If your dog requires surgery for their cruciate ligament disease, then it is important to follow their post-operative care instructions closely. These usually include:
- Restricted exercise – your dog will need to be confined for 6-8 weeks post-surgery, which means staying in a crate or small room in the house for most of this time. Your dog will not be allowed up and down stairs and they must stay on a lead to go to the toilet.
- Administering medication – Pain relief medication will need to be administered regularly at home during recovery.
- Monitoring wound healing – Keeping an eye on your dog’s surgical wound and stopping them from interfering with healing by using things like a buster collar.
- Mental stimulation – Restricted exercise can be tough, especially for active dogs. Careful use of puzzle toys/feeders, snuffle mats and plenty of TLC can help with this.
- Post-operative radiographs – Repeat radiographs (X-rays will be recommended after 6 weeks to determine if your dog can start to return to normal exercise.
- Controlled return to exercise – Once your dog has been given the ok to return to exercise, this must be done gradually. Guidance will be given on how to do this.
- Complementary therapies – Hydrotherapy and/or physiotherapy may be prescribed to build your dog’s strength and help aid their recovery.
Most dogs that require cruciate ligament surgery make a good recovery, provided post-operative care instructions are followed closely. They can return to living a relatively normal life. However, some dogs will develop cruciate ligament disease in the other knee at some point later down the line.
Dogs who have had cruciate ligament damage will also be more prone to developing osteoarthritis in that joint later in life. Keeping your dog at a healthy bodyweight and being careful to avoid activities that involve skidding and jumping can help. Joint supplements can also be useful.
Our vets are always on hand to discuss your dog’s individual needs should they require treatment for cranial cruciate ligament disease.
Summary
If you suspect your dog is suffering from cranial cruciate ligament disease, then contact us for an appointment. Our vets will talk you through each step of the process to help manage your pet’s return to recovery. As with most health concerns, the sooner you seek advice, the better the longterm outcome will be, so don’t hesitate to contact us on 01480772950
