Injuries to the cranial cruciate ligament in dogs are extremely common, especially in large active breeds. The majority of dogs who rupture this ligament do so because of degenerative disease in the joint weakening the ligament over a period of months or years. The trauma involved in the final rupture can be very minor. This is an extremely important point to be aware of when deciding how to treat the injury.


Most of these patients will benefit from surgery, but there are a wide array of techniques available for you to choose from.

Surgery involves two parts. Firstly, the joint is opened and any torn ligament or cartilage is carefully removed. Secondly, the joint needs surgery to stabilise it now there is no cranial cruciate ligament.
There are essentially two ways of doing this. The more basic technique involves placing a restrictive band of some form that attempts to replace the function of the lost ligament. The more complex techniques involve changing the structure of the bones to alter the forces acting on the joint.

Extracapsular surgery

This includes what was traditionally the most popular surgery, where a single or double strand of nylon leader line or Fiberwire is placed to try and replace the function of the original cruciate ligament. This can result in good function, but the larger the patient the less satisfactory the results tend to be. The implant is not physiological, in that it does not properly replace the original ligament, and can lead to a rapid progression of arthritis in the joint. Recovery times from surgery can be prolonged. This is a good option for small dogs, not so good for medium dogs, and not good for large dogs.

Tibial surgery

This group of surgeries involves making various cuts to the tibia (shinbone), and then securing it with a bone plate and screws. This results in the forces previously resisted by the cruciate ligament either being neutralised or transferred to another anatomical structure.

Return to normal function after surgery can be dramatically faster than with the traditional nylon band technique.

There are multiple versions of these advanced procedures. They include the TPLO, TTO, TTA and TWO.

The most successful technique in terms of normalising forces around the joint, and having the best long term outcomes, is the TPLO (tibial plateau levelling osteotomy). We are now able to offer this surgery for medium to large breed dogs. The surgery involves making a single, curved cut in the tibia, then rotating the joint surface around a set number of degrees, and finally stabilising it with a bone plate and screws.

TPLO is an operation with a long history of success in many countries. This is the “gold standard” surgery in specialist practices around the world for cruciate ligament injury. If the joint is suitable for this procedure, and if finances permit, this would be our recommended first choice surgery where possible.

The TTA (tibial tuberosity advancement) procedure is technically the simplest to perform, and comes in a variety of forms, depending on what plating system is used and what spacer is placed in the cut bone.

The TTA version we perform utilizes 3D-printed titanium wedge implants, and titanium plate and screws. The reason we use this technique over the other, often cheaper, TTA techniques relates to the wedge. Most spacers put into the cut bone are steel, and the new bone has to grow completely across the gap created in the bone in order to get full stability.

The titanium mesh allows the bone to grow through the mesh, eventually forming a bone-titanium mix. This means the bone only needs to grow a very short distance into the mesh in order to get rigid stability. What this results in is extremely rapid stability of the implant, very little discomfort very quickly after surgery, and a greatly reduced level of post-surgical complications. Titanium is also much more resistant to infection than steel.

TTA is a good technique for medium to large breed dogs. It cannot be done if the tibial plateau angle (measured on pre-operative xrays) is too high. This is why it is essential to have proper xrays of the limb performed before deciding which procedure is best suited to your dog.

TTO (triple tibial osteotomy) is a procedure that involves three cuts in the tibia. It combines features of the TPLO and the TTA. TTO is a very versatile procedure, that can cope with severe tibial plateau angles, and can be adapted to manage patellar luxation at the same time relatively easily.

TWO (tibial wedge osteotomy) involves removing a wedge of bone from the front of the tibia. This is a technique best suited to small breeds of dog.

Our recommendation for managing cruciate injury in dogs is:

  • Dogs under 15kg bodyweight with cruciate rupture or partial rupture: Extracapsular nylon band surgery or TWO.
  • Dogs over 15kg bodyweight with cruciate rupture or partial rupture: TPLO or TTA or TTO surgery.
  • Dogs over 15kg bodyweight which have had a previous nylon band surgery but the results have been unsatisfactory: consider revisional surgery with TPLO/TTA/TTO.

We have lots of dogs now who have had both knees operated on and returned to running and working. A dog who ruptures both cruciate ligaments can have the joints operated on very close together, which dramatically reduces recovery time.

After care

The period of rest after cruciate ligament surgery is quite long, up to 12 weeks, and it is critically important that the instructions given are followed closely in order to get the best results. We have a rehabilitation programme for you to follow during this period.

How to book

Call the Franklin Vets Customer Service team on 09 238 7486 to discuss transfer of your patient to our clinic for assessment and treatment. You may be asked to bring any clinical notes, x-rays images, and medications with you when you come.

Dr Paul Eason BVM&S MANZCVS (Surgery, Emergency & Critical Care)