What is Cranial Cruciate Ligament Disease?

What is Cranial Cruciate Ligament Disease?
What is Cranial Cruciate Ligament Disease?
By Rolando Quesada, Veterinarian, Anexa Vets Raglan

Is your dog showing any of these signs or symptoms?

  • difficulty rising from a sit
  • trouble jumping into the car
  • decreased activity level
  • lameness of variable severity
  • muscle atrophy (decreased muscle mass)
  • decreased range of motion of the knee joint
  • a popping noise (which may indicate a meniscal tear)
  • swelling on the inside of the knee joint (fibrosis around the joint)
  • pain
  • unwillingness to play
  • stiffness
If so, your dog could be showing signs of cranial cruciate ligament disease (CrCLD). The signs are variable and may include any combination of the symptoms above. Read the article below and have a chat with your vet if you are concerned.

The cranial cruciate ligament

The cranial cruciate ligament is one of the most important stabilisers inside your dog’s knee. The human equivalent is the anterior cruciate ligament (ACL).

The meniscus (Figure 1) is a cartilage-like structure between the femur and tibi. It has many functions, including shock absorption, position-sensing, and load-bearing and can be damaged when the cranial cruciate ligament rupture (CrCL) is ruptured.

What is a cranial cruciate ligament (CrCL) rupture?

CrCL results from progressive degeneration of the ligament over a few months or years rather than sudden trauma to an otherwise healthy ligament. Because this problem’s development is complex, and they experience varying degrees of rupture (partial or complete), it is referred to as ‘cranial cruciate ligament disease’ (CrCLD). This problem is the most common cause of hind limb lameness, pain, and subsequent arthritis. While the symptoms vary, the condition results in hind limb dysfunction and pain.

What causes cranial cruciate ligament disease (CrCLD)?

CrCLD is caused by a combination of factors: aging of the ligament obesity, poor physical condition, genetics, conformation, and breed. About 40-60% of dogs that have CrCLD in one knee will, at some stage, develop the condition in the other knee. Partial tearing of the CrCL is common in dogs and progresses to a complete tear over time.

This condition can affect dogs of all sizes, breeds, and ages, but rarely cats. Poor physical body condition and excessive body weight are risk factors for the development of CrCLD. These can be managed with physical conditioning with regular activity and food intake monitoring to maintain a lean body mass.

How do we diagnos a cranial cruciate ligament rupture?

Complete tears of the CrCL are easily diagnosed by a combination of gait assessments, physical examination, and radiography. Diagnosing partial tears on the other hand is more difficult. Specific palpation techniques can confirm instability of the knee, indicating CrCL rupture, but instability may not be present in early stages or partial tears.

X-rays allow the veterinarian to:

  • confirm the presence of joint effusion (fluid accumulation in the joint)
  • evaluate for the presence/degree of arthritis
  • take measurements for surgical planning
  • rule out concurrent disease conditions, including CrCLD of the opposite leg.

What treatment options does Anexa Vets offer?

A few treatment options are available for CrCLD. The best choice for your pet depends on many factors, including: activity level, size, age, skeletal conformation, and degree of knee instability.

Surgery is typically the best treatment since it is the only way to permanently control the knee joint instability, thus restoring function and comfort. The surgery entails two components: joint exploration (arthrotomy) and re-stabilisation. During arthrotomy, the joint structures are assessed, particularly the medial meniscus. If meniscal injuries are detected, the damaged parts are removed.

The procedures available to restore stability are categorized in two groups:

  1. Osteotomy techniques require a bone cut (osteotomy) which alters the way the extensor muscles act on the tibial plateau slope, rendering the knee stable by changing the biomechanics without directly repairing or replacing the CrCL. This can be done by advancing the attachment of the patellar tendon (Tibial Tuberosity Advancement (TTA)) or by rotating the tibial plateau (slope) (Tibial Plateau Levelling Osteotomy (TPLO)). Plates, screws and other implants are required to support the bone cut until the bone heals. These techniques are preferred due to their consistent results even in the more athletic of dogs, although they are more technically challenging and require more specialised orthopaedic equipment.
  2. Suture based techniques or extra-capsular suture stabilisation utilise suture material that is placed just on the outside of the joint (but under the skin) in a similar orientation of the original ligament, mimicking its function. The suture helps stabilise the joint long enough to allow the formation of scar tissue around the joint that will provide long term stability even as the suture gradually stretches or breaks. The main problem of this procedure is premature failure of the suture and progressive arthritis; therefore, this technique is generally reserved for small, older and inactive pets.

Post-operative radiograph demonstrating a TTA.

In general, compared to extracapsular repairs, advanced osteotomy techniques are regarded as the treatment of choice as they consistently deliver superior outcomes relative to limb function and athletic mobility with less progression of arthritis regardless of the age, size and lifestyle of the dog.

Anexa Vets offer all the treatment options mentioned above to best suit your dog’s needs. If you notice any symptoms however mild, please schedule an appointment as early detection is key to ensure the best outcome.

Date Added: Wednesday, 31st March 2021