It was a very sorry looking Maggie who hobbled into the consulting room on a Tuesday evening. Accompanied by the entirety of the Knight family, she was limping badly on her left back leg. Mr Knight explained that they just didn’t know what could have happened. She’d been for her usual walk, then after a lie-down at home she’d got up for her tea and was suddenly limping like this! They hadn’t heard her yelp, or seen her fall over or trip; and she was walked on the lead so hadn’t even been charging about.

The vet asked them to walk Maggie up and down so she could see her gait. Then she gave her a full examination. Maggie, despite being a 45kg Rottweiler, was absolutely terrified at the vets, and stood stock-still, shaking like a leaf. She made no reaction when the vet examined and manipulated her joints, and kept her legs very straight and stiff when the vet was trying to assess the joint stability. 

The vet explained that she suspected an injury to Maggie’s stifle (knee), given the degree of lameness and some swelling in the joint. This made the vet highly suspicious of a cruciate ligament tear. She gave them the option of booking Maggie straight in for x-rays the following day; or to give her a couple of days of rest and anti-inflammatory pain killers and see if she improves.

What is the cruciate ligament?

The cruciate ligaments in dogs are tough, fibrous bands of tissue which attach two bones together: the femur (thigh bone) to the tibia (shin bone). They support the knee joint, and prevent the tibia from sliding forward in relation to the femur. There are two of these ligaments: cranial and caudal. The cranial cruciate ligament is commonly injured in dogs.

Plan A – wait and see

The Knight family decided to give it two days, and took home some medication and an estimate for x-rays. Unfortunately, there was not much improvement, and Maggie came in for x-rays a few days later. Maggie had a short general anaesthetic for the procedure. And whilst she was asleep the vet could assess the joint much better, as she was fully relaxed.

When the Knights came to pick up Maggie, the vet explained that the x-rays and examination had confirmed a diagnosis of cruciate ligament disease in the left hindlimb. The joint was unstable, causing pain and inflammation which was why Maggie was limping.

What happens in cruciate disease?

As dogs age, their cruciate ligament gets worn and thin. Certain breeds are more predisposed to this, including Labradors, Rottweilers, Boxers and West Highland White Terriers, so a genetic predisposition is likely. The ligament gets worn down and eventually ruptures. This triggers inflammation, leading to pain and swelling. Often, the joint already has some arthritis due to this early wear and tear. The joint becomes unstable without the support of the ligament, and the femur moves down the tibia when the dog walks, leading to pain and damage to the menisci, the cartilage shock-absorbers of the joint. 

The Knight family were expecting this diagnosis, as the vet had mentioned it as a potential cause and having done some homework on the internet whilst waiting for news. They asked if the ligament might heal without surgery. The vet explained that while non-surgical management is an option for a small minority of cruciate patients, surgery would be a much better option for Maggie due to her size and the level of instability in the joint. 

Treating cruciate disease

There are multiple treatment options for this common orthopaedic problem. The choice will depend on multiple factors including breed, size and weight of the dog, and the severity of the problem (a full or partial tear). 

Non-surgical management consists of anti-inflammatory painkillers, weight management, exercise modification and physiotherapy. It is rarely recommended as a sole treatment, unless the risk of surgery is too high, such as in a patient with heart failure. Dogs over 15kg are unlikely to regain function of the joint without surgery.

There are a few different surgical options.

  1. Ligament replacement (lateral suture): a nylon suture is placed around the knee joint. It aims to regain stability of the joint, essentially replacing the ligament. The suture can break under strain, however, and so this technique is usually more suited to smaller dogs. 
  2. Tibial tuberosity advancements (TTA): a cut is made into the bone at the front of the tibia, altering the forces acting on the quadriceps muscle group, correcting the instability.
  3. Tibial Plateau Levelling Osteotomy (TPLO): a curved cut is made in the tibia, and the segment is rotated to level the previous slope of the tibia, meaning the femur no longer slips down. The segment is secured with a plate and screws. 

Plan B – surgery

The vet encouraged them to consider surgical options, with a TPLO being the preferred fixation method for this size of dog. The surgery would have to be performed at a nearby referral centre; as there was no vet at the local practice trained in this specialist surgery. The vet gave them an estimate to have the surgery done by the specialist, and discussed after-care with them. Maggie would need to be rested initially, and then started on a very gentle exercise program. X-rays would be taken 6 weeks after surgery to check the joint was healing well. 

The Knight family took the vet’s advice and took her to the referral centre for the TPLO procedure. The initial surgery went well, but Maggie later developed an infection in the wound. This required swabbing for culture at the lab, and two courses of antibiotics. 

Luckily, the Knight family had pet insurance

The costs from both the referral centre and the local vets were both fully covered under the same claim, so only one excess needed to be paid. The claim included the initial consultation and pain relief, the x-rays, the surgery and all the aftercare including antibiotics, lab tests and post-operative x-rays. 

Maggie is still nervous at the vets, but she doesn’t have her limp anymore. She still goes out with her family for long walks at the weekend, and enjoys play sessions when they meet her cousin, Mollie. Maggie’s knee occasionally gets a bit stiff due to the arthritic changes present, but she’s been put onto a joint supplement and has anti-inflammatory medication on particularly bad days. 

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