Cruciate Ligament Disease

The cranial cruciate ligament (CCL) - equivalent to the ACL in humans - stabilises the stifle (knee) joint by preventing the tibia from sliding forward under the femur. CCL disease in dogs is not simply a traumatic injury as it often is in people; it usually involves progressive degeneration of the ligament over time, eventually leading to partial or complete rupture.

The result is stifle instability, pain, and rapid development of osteoarthritis. In dogs, the condition is bilateral in 40–60% of cases - if one CCL ruptures, the other side is significantly more likely to follow within 1–2 years.

Recognising the injury

Acute complete rupture: Sudden onset of non-weight-bearing or severely reduced weight-bearing on a hind leg. Often follows a sudden movement - jumping, twisting, running. The dog may hold the leg completely off the ground.

Partial rupture or gradual degeneration: Intermittent or low-grade hind limb lameness, particularly after exercise. Sits with the affected leg out to the side (a compensatory posture to reduce stifle stress). May improve with rest and return with activity.

After diagnosis: Log daily:

• Weight-bearing: full, partial, or non-weight-bearing
• Morning stiffness
• Willingness to exercise
• Any swelling around the stifle joint
• Pain response on handling or joint manipulation

Diagnosis

Diagnosis is typically based on a combination of:

• Lameness examination
• Cranial drawer test and tibial compression test - manual tests that detect abnormal movement in the joint due to ligament instability; usually performed under sedation
• X-rays - confirm joint effusion (fluid) and reveal secondary arthritis; don't visualise the ligament itself
• MRI or arthroscopy - for definitive ligament assessment in uncertain cases

Treatment options

Conservative management (rest, physiotherapy, pain relief) alone is generally not recommended for medium to large dogs - instability persists, the stifle continues to damage, and quality of life remains poor. Surgery is the standard recommendation.

Surgical options:

• TPLO (Tibial Plateau Levelling Osteotomy): Changes the angle of the tibial plateau so the stifle is stable without the CCL. Most commonly performed in the UK, particularly for larger dogs. Good long-term outcomes.
• TTA (Tibial Tuberosity Advancement): Changes the direction of the patellar tendon to neutralise stifle forces. Alternative to TPLO.
• MRIT (Modified Retinacular Imbrication Technique) / Lateral suture stabilisation: Uses an implant to replace the CCL mechanically. Generally reserved for small dogs or dogs not suitable for osteotomy procedures.

Post-surgical recovery is 12–16 weeks of controlled rest, with physiotherapy starting typically at 4–6 weeks.

Monitoring post-surgery

Log daily during recovery:

• Weight bearing - track week by week; improvement should be gradual and consistent
• Swelling at the incision site
• Any discharge, increased heat, or wound changes
• Exercise amount (controlled, usually lead-only walks to begin with)
• Pain or discomfort signs

Report any sudden worsening, wound complications, or failure to progress to your vet promptly.

The other leg

If your dog has ruptured one CCL, monitor the opposite hind leg closely. Signs to watch for: any reluctance to bear full weight, a subtle change in gait, sitting with the leg extended. Early detection of partial rupture in the second leg allows planning rather than emergency response.

When to contact your vet

Go to the vet urgently if:

• Sudden non-weight-bearing hind leg lameness

Contact your vet soon if:

• Intermittent hind leg lameness that is recurring or not resolving
• Post-surgical complications (swelling, discharge, sudden worsening)
• Concern about the opposite leg

Frequently Asked Questions

Is surgery always needed? For medium and large dogs (over approximately 15kg), surgery is almost always recommended - conservative management leads to persistent instability, ongoing joint damage, and poor quality of life. For very small dogs, conservative management with physiotherapy has better outcomes and may be appropriate.

How much does CCL surgery cost in the UK? TPLO and TTA typically cost £2,500–£4,500 per leg at specialist orthopaedic centres. Check your insurance policy - this is one of the most common orthopaedic insurance claims.

My dog ruptured one CCL - should I do anything to protect the other leg? Weight management is the most important protective measure - overweight dogs place greater load on all joints. Controlled exercise (avoiding high-impact or high-rotation activities), physiotherapy, and joint supplements may also be beneficial.

How long does recovery from TPLO take? Full recovery takes 12–16 weeks. The first four weeks typically involve strict rest (short lead walks only). Physiotherapy begins gradually. Most dogs are walking well by 8 weeks; full return to normal activity is around 4 months.

Can a dog live well with an untreated CCL rupture? Some dogs, particularly small breeds, adapt to some degree. But an unstable stifle continues to damage - cartilage erodes, arthritis advances, and the meniscus (cartilage pad in the joint) is at risk of tearing (a painful complication). Quality of life is generally significantly better with surgical stabilisation.