We demystify the myriad of surgical procedures being offered for treatment of cruciate ligament disease.
Once a dog has cruciate ligament disease, arthritis can develop within the knee joint, and the joint will never be the same as it was prior to having cruciate problems. Surgery is the best method of preserving as ‘normal’ a joint as possible. There are many different options for cruciate ligament repair in dogs and it is understandable that it can be confusing for pet owners to know which is best for their dog. At Southern Animal Health we offer the surgical procedures that, based on available evidence, we believe will result in the most rapid return to normal function, as well minimising progression of degenerative changes (arthritis) within the joint. We recognise that there are other veterinarians offering other procedures so I thought that providing a summary of currently available procedures may help demystify the minefield of choices.
Since the first surgical procedure for stabilising the knee joint in dogs was described, there have been more than 60 surgical variations, each with proven or potential advantages and disadvantages. New procedures have been developed over the years as our understanding of cruciate disease and the biomechanics of a cruciate-deficient joint have improved.
The procedures currently available can be divided into three broad categories:
1. Extracapsular stabilising procedures – These techniques stabilise the knee joint by placing a strong synthetic suture (prosthetic ligament) outside the joint capsule. The suture is anchored around the femur and tibia to limit abnormal movement within the joint and mimic the function of the torn cranial cruciate ligament. Over time, scar tissue develops to help provide additional long-term stability.
A common example is the Lateral Suture Technique (also known as the DeAngelis suture). This approach is most commonly used in smaller dogs or less active patients, as the implant does not provide the same long-term mechanical strength as bone-altering procedures.
2. Intraarticular grafts – These techniques involve placing a graft made from the dog’s own tissue inside the knee joint to replace the damaged cranial cruciate ligament. In human medicine, intra-articular grafts are commonly used and can produce excellent results. However, in dogs they have generally not provided consistent or reliable long-term stability.
For this reason, they are now rarely performed in veterinary orthopaedics and are considered an outdated technique, with more predictable surgical options now available.
3. Geometric techniques – These techniques involve surgical modification of the geometry of the knee joint to neutralise the abnormal shear forces that occur once the cranial cruciate ligament is damaged. Rather than replacing the ligament itself, these procedures change the biomechanics of the joint to achieve stability during weight bearing.
Commonly used procedures in this category include TWO (or CWO), TTA, MMP, TTP, TPLO, and CBLO. Each of these techniques achieves stability in a slightly different way, and they vary in terms of indications, advantages, and limitations. These procedures, along with their respective pros and cons, are described in more detail below.
Extracapsular techniques can deliver excellent outcomes in smaller dogs. We currently use the DeAngelis (lateral suture) technique, a proven and widely used method of stabilising the knee after cranial cruciate ligament rupture. This procedure places a strong synthetic suture outside the joint to restore stability and support healing, allowing scar tissue to form and reinforce long-term function.
Geometric techniques are generally the preferred option for dogs over 25 kg. These procedures require a high level of surgical expertise, as well as significant investment in specialised equipment, which is why we carefully evaluated the available evidence when selecting which techniques to offer our clients.
Choosing the most appropriate surgical technique
There is no single “best” technique for all dogs, and the most appropriate surgical approach depends on a range of factors including the dog’s size, activity level, conformation, and individual joint anatomy. For this reason, we do not take a one-size-fits-all approach to cruciate ligament repair.
In general, geometric techniques are often preferred for larger dogs (over 25 kg) due to the increased mechanical forces placed on the knee joint. These procedures are designed to neutralise the abnormal forces within the joint rather than relying on an artificial ligament, making them well suited to bigger and more active patients.
That said, all surgical options must be considered on a case-by-case basis. We carefully assess each patient and discuss the most appropriate technique with owners to ensure the chosen approach is tailored to the individual dog and their lifestyle.
Geometric techniques do require a high level of surgical expertise and specialised equipment. For this reason, we have thoughtfully selected which procedures we offer, based on current evidence, clinical outcomes, and what we believe provides the best balance of safety, reliability, and long-term function for our patients.
So….What are all these different procedures, and what do all those letters stand for?
Lateralisation Suture or DeAngelis technique
A nylon fishing line prosthesis is placed around the outside of the knee joint. This procedure is relatively easy for an experienced veterinary surgeon to perform and requires minimal specialised equipment. As such, most vets out there offer it.
Tightrope
This procedure involves stabilising the knee joint using a strong synthetic ligament-like prosthesis that is positioned through carefully placed bone tunnels in the femur and tibia. The implant is anchored in a way that closely replicates the direction and function of the dog’s natural cranial cruciate ligament, helping to control forward movement and internal rotation of the tibia.
By restoring mechanical stability to the joint in this way, the procedure allows the surrounding tissues to heal and adapt, supporting improved joint function over time.
TWO (Tibial Wedge Osteotomy), also known as CWO (Closing Wedge Osteotomy)
This involves removing a wedge of bone from the tibia and placing a bone plate to hold the bone together. The aim of the procedure is to level the top of the tibia bone, thus neutralising shear forces that occur when the cruciate ligament is damaged. This was one of the earlier geometric procedures developed (and is still a good one), but has been superseded by other techniques. The main disadvantage of this technique is that it slightly modifies the standing angle of the leg. I have done many of these over years and we do still offer it in certain cases.
TTA (Tibial Tuberosity Advancement)
A cut is made through the tibial crest (a section of bone at the front of the tibia) and this piece of bone is advanced forward and held in place with a titanium spacer cage and a specially shaped bone plate. The aim is to change the angle of the tendon attached to the kneecap relative to the tibia and neutralise shear forces within the joint. Many vets elect to offer this technique as it has a shorter learning curve than some of the other geometric procedures. Review of the literature shows that the results from this technique are very good, however it does carry a higher incidence of meniscal injuries in the medium to long term post-operative period. (The menisci are C-shaped cartilage pads that act like cushions within the knee joint. Meniscal injury causes pain and progression of arthritic changes).
MMT (Modified Maquet Technique) or sometimes known as MMP (Modified Maquet Procedure)
This uses the same principal as the TTA, except that the tibial crest is stabilised in a different manner – either a wedge or cage is used along with a wire. No plate is applied. At a recent orthopaedic conference that I attended, most specialist surgeons were quite negative about this procedure, having personally had numerous cases with complications referred to them. The main concern is that if not doing well it is almost impossible to do a revision surgery due to the nature of the implant.
TTO (Triple Tibial Osteotomy)
This combines the features of the TTA and the TWO. Three cuts are made in the bone and a bone plate applied. This technique was developed in Australia and is only done is Australasia, and as such, there are a lot less published studies of results and long-term outcomes. In fact, when I was at anorthopaedic workshop in Europe, none of the European or American vets that I met knew much about this technique at all.
TPLO (Tibial Plateau Levelling Osteotomy)
A circular cut is made in the top of the tibia bone and this segment is rotated and then fixed in position with a bone plate. The effect is to level the top of the tibia bone and neutralise shear forces. This procedure is world-recognised as the ‘gold standard’ for cruciate repair in dogs, and is the preferred surgical technique of just about every surgical specialist that I have discussed the subject with. Most clinical studies show that TPLO offers return to normal function (even in athletic dogs), with a faster recovery to normal weight-bearing post-operatively.
CBLO (CORA Based Levelling Osteotomy)
A variation of the TPLO, but the curved cut is made lower done on the bone and is fixed in position with a bone plate and specialised screw. This technique has been a more recent development. When it first came out many vets found the concept quite exciting. However, the evidence has not really stacked up just yet and I believe it’s benefits are limited to cruciate ligament disease in immature dogs (an uncommon situation) or for revision surgery of a failed technique where cuts have already been made higher in the bone.
At Southern Animal Health our aim is to recommend procedures with a good evidence base for a successful outcome; and we like to be able to offer you the best. On review of current literature, there is plenty of information on short-term results of various cruciate surgeries but there are not many studies that report on intermediate to long-term outcome. There are also not many studies that compare one procedure to another. The most commonly performed procedures around the world (and therefore the most commonly compared procedures in scientific papers) are the Lateralisation Suture (LS), TTA and TPLO. Most evidence strongly supports TPLO in the ability of dogs to return to normal function, with TPLO being superior to LS in the immediate post-operative period. Therefore, based on the evidence, we have chosen to recommend and offer TPLO as our gold-standard cruciate ligament repair option.
View this study of a comparison of long term results three years after surgery, which clearly shows that TTA (and MMP) candidates show more arthritis and more discomfort than dogs repaired with TPLO.
TTA and MMP is cheaper, easier to do, and can initially have seemingly as good a result as TPLO, but revision on the higher percentage not doing so well is difficult with TTA and impossible with MPP, and long term results are not as rewarding as TPLO.
Please refer to our Cruciate Ligament rupture page for further information about the surgical procedures that we perform at SAH. We are of course happy to discuss any furthers questions you may have, so feel free to give us a call.