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Cruciate Ligament Injury and physiotherapy

There are two bands of fibrous tissue called the cruciate ligaments in each knee joint. They join the femur and tibia (the bones above and below the knee joint) together so that the knee works as a hinged joint.   They are called cruciate ligaments because they “cross over” inside the knee joint.

Humans virtually have the same anatomical structure of the knee. Cruciate ligament rupture is a common knee injury of athletes. The term anterior cruciate (ACL) is used to describe the identical anatomical structure in humans or cranial cruciate (CrCL) in the dog.  The cause of this injury however is quite different in the dog.

Cranial cruciate ligament injury is reputedly the most common canine orthopaedic condition and the most common disease of the stifle (knee).  The knee joint is a hinged joint and only moves in one plane, backwards and forwards. Deficiency of this ligament results in both translational and rotational instability of the stifle joint that leads to development of osteoarthritis.  This is mostly due to a disease process and rarely due to an acute injury in the dog.  The ligament may become stretched or partially torn and lameness may be only slight and intermittent, but a process of inflammation, or arthritis, is occurring in the joint at the same time. With continued use of the joint, the condition gradually gets worse until rupture occurs.

How is it diagnosed?

With traumatic cruciate rupture, the usual history is that the dog was running (e,g ball at the beach) and suddenly stopped or cried out and was then unable to bear weight on the affected leg. The dog will often “toe touch” and place only a small amount of weight on the injured leg.

A vet may examine your dog under sedation and perform a test called a cranial drawer or tibial thrust to assess the stability of the knee and presence of discomfort.  Xrays may also be necessary and these results will be used to determine rehabilitation options and types of surgical procedures available to your dog.  Depending on the size, breed, conformation (shape of the leg) etc, certain types of surgery will be more successful or recommended.

Inside the knee joint are pieces of cartilage called menisci. The menisci act as shock absorbers between the femur and tibia. Many times these cartilages are also damaged when the cruciate ligaments rupture. They are usually repaired at the same time as the ligament surgery and can contribute to prognosis.

Rehabilitation options

Dogs under 10kg may improve without surgery, especially aged patients.  A controlled rehabilitation program designed specifically by your Physiotherapist will maximise the recovery and reduce the progression of muscle wasting, secondary problems (e.g back/hip pain) and severity of arthritis.  Dogs over 10kg usually require surgery to heal. Unfortunately, most dogs will eventually require surgery to correct this painful injury and sometimes after a partial injury, surgery may improve the long term outcome sooner rather than later.

The majority of cases (especially of larger breeds) are reported to have better clinical outcomes with surgical intervention.  There are many different surgical techniques to re-stabilize the joint (static or dynamic) to neutralize the tibiofemoral shear forces in a CrCL deficient knee.  Alternatively, conservative management may be recommended with Physiotherapy to improve stability and muscle balance to the stifle/hip/pelvis; limit the progression of OA, reduce pain/inflammation, and to prevent /limit secondary complications.  Physiotherapy for CCL rehabilitation has been extensively researched in human literature.

Benefits of Physiotherapy

In both humans and animals, Physiotherapy is vital to maximise recovery and clinical outcomes.  It is important to begin physiotherapy as soon as possible after surgery or injury (generally 7-10 days post op depending on the type of surgery performed).   Education of the dog’s owner is an integral part of rehabilitation to ensure correct walking pattern is achieved.  The underwater treadmill is invaluable to examine and correct gait patterns.

Inflammation/Pain

Immediately post op Physiotherapy techniques are effective to reduce pain and inflammation, and aid healing.  Ice, massage, passive range of movement (ROM), and acupuncture, have all been reported to be effective.

Range of movement (ROM)

Restoration of full knee extension is necessary for proper ambulation (and reduction of forces for progression of arthritis).  In human literature it has been shown that 3-5° loss of extension will significantly impact upon outcome.  Control of effusion and restoration of normal ROM will optimise outcomes.

Muscle Stability/Strength

In human rehabilitation, running/sport specific skills or explosive activity is restricted for 4-6 months post op. It has been found to be 12 months before muscle circumference has been returned to normal.  The same has been correlated in canine rehabilitation.  In humans the VMO (vastus medialis oblique) has been shown to waste 10%/day due to pain, swelling and inflammation. Good quadriceps function is one of the cornerstones of ACL rehabilitation.  Specific exercise instruction is vital and needs to be individual focussed to ensure correct rehabilitation and limitation of secondary complications.

Underwater treadmill (UWT)/swimming:

Swimming has the advantages of buoyancy of the water, resulting in less force on the limbs.  This encourages flexion of the limb, reduced impact and is a great cardio-vascular exercise for overweight/de-conditioned dogs.  UWT walking results in increased stance time, stride length, reduced joint flexion velocity, and greater muscle force due to water resistance.  As gluteal/hamstring strength and weight bearing extension is vital for rehabilitation, the UWT is preferably to swimming and this may begin when the wound has healed.

Is post-operative care difficult?

It is important that your dog have limited activity for six to eight weeks after surgery. Provided you are able to carry out your veterinarian’s instructions, good function should return to the limb within three months to 6 months.  Unfortunately, regardless of the technique used to stabilise the joint, arthritis is likely to develop in the joint as your dog ages. Weight control and nutritional supplements such as glucosamine and omegas (fish oils) may help delay the onset of arthritis in your pet

Is obesity such a problem?

Obesity can result in cruciate ligament rupture. If your dog is overweight, the recovery time will be much longer. Obesity also increases the risk of injury to the other knee. Weight loss is as important as surgery in ensuring rapid return to normal function.

Conclusion:

Emerging evidence suggests best outcomes will be imparted both conservatively and post reconstruction by a combination of aggressive early control of swelling and range of movement return, specific early strength and stability exercises esp quads/gluteals/hamstrings and a neuromuscular training programme.  After TPLO the effects of early intensive Physiotherapy have been shown to significantly improve range of movement, thigh circumference and weight bearing score, thus reducing the progression of arthritis. Some dogs may recover with near-normal function, whereas others have moderate-to-severe OA, requiring long-term management.  Physiotherapy should be considered vital as part of the management of Cruciate ligament disease.

Any further questions feel free to contact Brooke further.

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