Tibial Tuberosity Transfer (TTT)

Patients may require this operation if they have marked mal-alignment of their patello-femoral joint joint and this is contributing to their problems. In some cases this could be patellofemoral instability (where the knee cap keeps dislocating), or pain behind the knee cap due to breakdown of the cartilage behind the knee cap, and / or an acute injury to the cartilage. The latter may occur as a result of a fall onto the knee cap, or part of a twisting injury to the knee.

The operation may be performed on its own, or in combination with soft tissue procedures, such as medial patellofemoral ligament repair or reconstruction. There is a separate description of these soft tissue procedures in the “knee” section of “orthopaedic surgery” on this website for more details.

The reason to perform this operation is based the alignment of the quadriceps, the deepest part of the trochlea (the groove in which which the patella sits), and the attachment of the patellar tendon to the tibia. Ideally these should all be collinear when the knee is bent to 90 degrees. In some patients they are not, and this angle is similar in some ways to the “Q-angle”.

The most accurate way to measure this ankle is on either a CT and / or an MRI. The best way to measure it, is on these images, and record it as the tibial tuberosity – trochlear groove distance (TT-TG). Dr. Porter will make a decision on whether or not this should be performed on the basis of the patient’s symptoms and the imaging.

The operation is performed in an operating theatre with the patient under a general anaesthetic.

The first part of the operation is an arthroscopy (key-hole surgery), during which the entire knee is checked and any cartilage, meniscal or other damage is dealt with. In some cases the cartilage behind the knee cap will be treated with repair, grafting or a treatment called microfracture. The latter may be appropriate for relatively small,  deep or “punched out”, full thickness cartilage defects. It involves making small drill holes into the underlying bone, thus stimulating both repair and the release of marrow cells which have the capability of forming cartilage-like coating of the bare area of bone. In these cases the TTT is often perform to reduce the compressive load on this area to enhance healing and reduce further wear and tear in that area.

The second part of the surgery requires an incision, that is, an open procedure. The upper end of the shin bone (tibia) and the attachment of the patellar tendon to bone are exposed. A cut through the bone is planned, so that a wedge of bone including the attachment of the patellar tendon can be shifted to the desired position. The angle of the cut will determine how much the patellar tendon is move medially (inwards) and how much it is move forwards (anteriorly). Generally speaking more shift anteriorly is required in those knees where the problem is related to cartilage damage, rather than instability of the patella.

Once the cut is made, the  bone is shifted to the desired position and secured with titanium screws. Usually 2 x 6.7mm diameter titanium screws are used. These are counter-sunk into the bone, rarely have to be removed, and do not prevent MRIs from being performed in the future.

At the end of the operation, the leg is placed in a range of motion (ROM) brace, locked to hold the knee straight.

Patients usually spend one night in hospital, for pain control and to receive intra-venous antibiotics. Patients will also take a blood thinner, for 10-14 days post surgery.

Patients will go home the day after surgery, and Dr. Porter will review the patient 6-13 days post surgery in his rooms. This will have been organised for you, and an SMS reminder will be sent to the patient’s mobile phone. Patients can phone the rooms to confirm the date a time.

Patients can put full weight through the operated leg, as long as the ROM brace is locked in full extension, that is, locked straight. The brace can be removed at night when comfortable to do so, but most patines prefer to wear the brace at night until the pain has settled.

The brace can be removed for the physiotherapy-supervised rehabilitation, but should be worn at other times.

Patients will perform the simple earlier exercises, as detailed, and some will start physiotherapy prior to the first post-operative review. When Dr. Porter reviews you, a letter can be sent to the physiotherapist which will include the operative report.

Patients will be give a hand out similar to the following which details the early post-operative management.

Patient handout for tibial tuberosity transfer

Immediately post-surgery

• You will wake up in the recovery ward with your leg held immobile in a brace
• The wound will be closed with stitches, covered with dressings, and a heavy bandage
• A nurse will administer pain killers as required and keep you comfortable
• You will be discharged from the recovery ward when you have recovered from the general anesthetic and your pain is under control
• If you are staying in the hospital over-night you will be transferred to your ward
• If you are going home you will be discharged in the company of a carer, when you have been able to drink and eat, and your pain is under control with oral medications. You will also have to be able to mobilize on crutches while non-weight-bearing on the operated side. Most patients will spend at least one night in hospital.
• Your surgeon will review you before discharge and explain to you the findings at surgery and the procedure performed

Discharge to first post-operative review

• You will not be able to place any weight through the operated leg until the post-operative review.
• Keep the limb elevated when not mobilizing on crutches, and keep the latter to a minimum for the first week. This will help to reduce swelling and control pain
• Take the medications as prescribed by your anaesthetist to control pain
• You may start physiotherapy within a week of surgery, and the physiotherapist will supervise your rehabilitation along the guidelines details in the attached table
• Phone the surgeon’s rooms to make an appointment 8-13 days post-surgery

First post-operative review – (        /          /          )

• You will be reviewed by your surgeon 8-13 days post-surgery. He will assess the healing of the incisions and remove the sutures
• He will liaise with your physiotherapist if any alterations in the standard rehabilitation regimen are indicated
• You will be allowed to commence touch weight bearing with the brace locked in full extension, from 2 weeks post-surgery. The amount of weight bearing and range of motion will be increased as per the attached table. A second review will be schedule for 2 months post-surgery. An x-ray of the knee will be performed as close to the second review as possible.
• You will continue with physiotherapy and you will be allowed to commence touch weight bearing and progress to full weight-bearing with the brace locked in full extension, as long as pain free. However this is ONLY with the brace locked straight.

Second post-operative review

• The surgeon will review you and the x-rays to check healing of the osteotomy site
• If all is well you will be allowed to begin to perform partial weight bearing exercises, and the brace can be opened to allow some bending of the knee while weight bearing. However this is only possible when you have sufficient muscle strength, which your physiotherapist will be able to determine.

Third post-operative review

• This will be 4-6 months post surgery and prior to your return to full sporting activity
• Running and other impact activities may be slowly introduced when you are at least 3 months post surgery, and your strength is at least 75% of the opposite leg
• Return to full sport is usually possible when you are 4-6 months post surgery, and your strength is 90% of the uninjured side. This will vary with the particular sport concerned.

Complications

If at any stage your experience any of the following:

• Pain not controlled with elevation and the medication prescribed
• Shortness of breath, chest pain, fevers, chills, night sweats, general malaise, color changes or swelling that do not resolve with elevation
• Any symptoms about which you are concerned

Contact your surgeon via his rooms or your local private hospital. If he is not contactable attend your local GP, or local A&E department. The latter will be able to assess you, commence treatment if required, and contact the surgeon.

Patients will follow the standard physiotherapy protocol for this procedure, albeit with some alterations on occasions.

The physiotherapy guidelines are detailed in the table below.

Patients can perform upper body weights when they are confident enough to get around the gym safely.

Swimming with a pool buoy may be possible within a few weeks, as long as the wounds have healed completely.

Use of a stationary bike (high cadence, low resistance), and / or deep water pool running are possible around 2 months.

Distal patellar realignment rehabilitation programme