Tibial Tuberosity Advancement (TTA) Surgery
What is cranial cruciate ligament disease?
The cranial cruciate ligament (CCL) is the main stabiliser of the stifle joint
(knee). CCL tears are the most common orthopaedic problem in dogs and typically occur secondary to degenerative changes in the ligament. Rarely, dogs may be affected as young as 3 or 4 months of age. A number of factors may influence early onset of degeneration including genetics, sex, hormones and obesity and degenerative changes will typically affect the CCL in both stifles.
Purely traumatic injury is rare, although trauma may be associated with tearing of an already weakened ligament.
There are a number of techniques that can be used to manage a tear of the CCL and your vet may have discussed various options with you. The procedures most commonly favoured by orthopaedic surgeons are the tibial plateau levelling osteotomy (TPLO) and tibial tuberosity advancement (TTA). This guide focuses on TTA surgical treatment, risks and complications together with post-operative care and your responsibilities as an owner.
Surgical treatment TTA
Following radiographs your pet is prepared for surgery. During surgery we inspect the knee (stifle) joint. This may involve removing the torn remnants of the cranial cruciate ligament. If most of the ligament remains intact then this can be left alone. The menisci (cartilage joint pads) are inspected. The medial (inner) one is the most common one to become damaged. Any torn areas are usually removed or they can cause persistent lameness.
The TTA procedure involves making a cut through the front of the tibia (tibial tuberosity). This is then moved forwards and a titanium cage is placed in the gap. The bone is secured with a plate/ fork and screws through the tuberosity. The intention of this is to alter how the joint works (biomechanics) such that dynamic stability is created. This mimics the function of the cranial cruciate ligament. Following surgery radiographs (x-rays) are taken to assess the positioning of the implants. Patients are normally hospitalised overnight for further pain relief and should be discharged the next day. Radiographs are repeated after 6-8 weeks to assess the healing of the bone.
Surgery risks and complications
Following a TTA, the majority of dogs are able to return to their normal activities. Many surgeons consider recovery to be more rapid with TPLO or TTA compared to other techniques. Nevertheless, it may take six months or more before a dog has fully recovered. Dogs with chronic knee problems and especially those with substantial muscle wastage and/or dogs that have had previous surgery will be expected to progress more slowly. As with any surgery, complications may arise and are detailed below, although serious complications are uncommon.
During surgery the patellar tendon can be seriously damaged, however this is extremely rare but a serious complication.
Potential post-operative complications
Infection is an uncommon complication as strict sterile techniques are used during the surgery and antibiotics are administered during and potentially after the procedure. Should infection occur, early detection and treatment often results in rapid resolution.
Removal of the implants may be required once the bone has healed. More serious problems may occur if infection progresses untreated or if your dog suffers an infection that is resistant to multiple antibiotics e.g. MRSA. If you suspect an infection contact your vet immediately.
Some medical conditions will increase the risk of a post-surgical infection, such as pre-existing infection elsewhere e.g. skin and ear infections, cystitis, gingivitis etc. Pre-existing infections should be eliminated whenever possible. Some chronic infections e.g. skin and ear cannot be entirely eliminated, yet it may still be in your dog’s best interests to undergo surgery despite some level of increased risk. Pre-surgical treatment will aim at minimising the risk of infection.
Fracture of the tibial tuberosity occurs relatively rarely. Fractures of the tibial plateau are a rare but serious complication. This typically requires substantial force soon after surgery before the bone has had time to heal and remodel. This should not occur if dogs are appropriately managed after surgery i.e. dogs should NOT be free-running in the house or outside in the early post-operative period.
Excessive early activity increases the risk of damaging or breaking the plate or screws.
Even after the bone has healed it is still important to have a controlled, gradual increase in activity, similar to human patients undergoing rehabilitation. If activity in dogs is increased too quickly after surgery, straining of the patellar ligament or other joint structures may occur. Rest and anti-inflammatory medications typically resolve these problems.
Arthritis is usually present at the time of surgery and will progress to some degree regardless of treatment. If the CCL has been ruptured for some time significant additional joint injury may have occurred and arthritis is typically more advanced. Previous knee surgery is also often associated with a more rapid progression of arthritis.
It is not possible to reverse the arthritic changes in the joint or undo other damage already done but the surgery will stabilise the knee thereby reducing inflammation, which may help to reduce the ongoing progression of arthritis.
Damage to the meniscus (cartilage pad in the knee) may occur following tearing of the CCL ligament i.e. it is a complication associated with cruciate ligament insufficiency. Meniscal injury may still occur following surgery and may occur at any time i.e. weeks or even years after surgery. If this occurs additional surgery is usually necessary to manage the torn meniscus.
Post-operative care and your responsibility as the owner
A pad may be covering the wound at the time of discharge from the hospital. This can be removed after two days or before if soiled. Usually there will be no external stitches as the stitches are buried under the skin and will dissolve. There should be no discharge coming from the wound. Please inform us if the wound starts to discharge or if it looks excessively swollen. Please do not apply anything to the wound as it can cause irritation.
We normally discharge patients with a buster collar. This is to prevent your dog from licking the wound and making it sore. Please leave the buster collar on for 2 weeks. If an infection were to get in through the wound, this could result in further surgery.
We recommend ice packs for 10 to 15 minutes several times daily in the first few days following surgery, to reduce swelling and improve comfort. Regular, gentle massage (sweeping motions from ankle to hip) may help dissipate any oedema fluid. Massage techniques will be advised at discharge. Your vet will talk you through this if this is something your dog requires.
It is better to be safe than sorry so if you are not sure about anything please contact us. If you are provided with pain killers please follow the instructions as directed and inform us if there is any vomiting.
Your dog should be kept confined (ideally to a large cage or alternatively a single room with non-slip flooring) to restrict activity. Confinement should
be maintained at all times for the first six weeks following surgery.
We advise the following exercise programme after the operation:
Short lead walks in the garden (a few minutes, four to six times daily) are recommended to allow toileting. A support belt/sling is useful in the first week when walking as this will reduce stress on the joints. Stairs should be avoided.
Four weeks following surgery lead walking may commence, provided limb function has already significantly improved post-surgery. Walk slowly for 5 minutes at a time, twice daily, but maintain confinement at other times. Lead walking may gradually increase but should not exceed 10 minutes at a time, twice daily for the first six weeks following surgery.
Hydrotherapy is beneficial (but not essential) to recovery but should only be performed in a centre with qualified personnel. Hydrotherapy may commence at three to four weeks post-surgery in a water treadmill, or at four to six weeks following surgery in a swimming pool. Any activities prior to confirmed healing of bone will introduce risk e. g. car travel to and from hydrotherapy, slipping/falling.
You should see your own vet 5 days after surgery to ensure all is progressing as planned. If there are stitches present these will need removing at your own vet at 10-14 days.
We will ask to see you and your pet at 6-8 weeks post-surgery. This recheck will involve x-rays to assess the implants and the healing of the bones. You will need to fast your pet in the morning before this appointment. If everything is progressing well, exercise can be increased further, which the surgeon will discuss with you at discharge.
If you have any queries, we are always happy to answer them.
Orthopaedic Surgery Guide