Tibial tuberosity osteotomy (TTO)

Deciding whether to have knee surgery can feel overwhelming. This guide will help you understand your knee surgery options, benefits, risks, and recovery so you can make an informed decision about the right treatment for your condition.

Tibial tuberosity osteotomy (TTO) is an operation that is used to treat patella alta (high riding patella), which is associated with two main conditions: patellofemoral instability and anterior knee pain (due to lateral patella tendon conflict see here - link). It involves detaching the patella tendon attachment to the tibia with a block of bone, moving is down (distalising) and fixing it with a metal plate and screws. This brings the patella (kneecap) down to sit within the groove on the front of the femur. For stabilisation surgery, it is usually combined with additional procedures (trochleoplasty or MPFL reconstruction) at the same time.
Prior to considering surgical reconstruction, patients must complete a course of physiotherapy to strengthen the core, gluteal and quadriceps muscles that allow normal knee function and stabilise the patella. Bracing or taping can sometimes help stabilise the patella, and improve knee pain.
The surgery will be explained to you by Mr Smith in clinic, the alternatives, likely recovery period and any associated risks discussed. You will have a pre-operative clinic appointment to ensure that you are safe for surgery, and that there is no aspect of your health that can be optimised prior to having surgery. You will be informed at this stage when to stop any regular medications, and what time you can eat and drink until prior to the surgery.

On the day of surgery you will see Mr Smith and the anaesthetist prior to the surgery, to ensure that all questions have been addressed. The consent form will be checked with you, and the correct leg marked. You will often see a physiotherapist prior to your surgery also.
The procedure is usually performed under a general anaesthetic (fully asleep), with a nerve block in the thigh for pain relief.

You will be given antibiotics into the vein at the time of surgery to reduce the risk of infection.

An incision is made on the outer side of the lower leg, and the muscle carefully retracted backwards to expose the side of the tibia. The patella tendon and soft tissues are protected.

The attachment of the tendon to the bone is removed with a block of bone (about the size of a domino). This ‘domino’ is then moved down by a calculated amount, and fixed with a metal plate and screws.

The incisions are then washed with sterile water, and closed with stitch that absorbs. Adherent dressings are applied, with a bandage over the top.

The knee is placed in a splint for 3 weeks, but this is only worn when walking and can be removed at other times.
The surgery takes under an hour to perform. Often it is combined with a trochleoplasty or MPFL reconstruction, which will increase the surgical time.
For the majority of patients the metalwork does not cause a problem and will stay in. Approximately 1 in 5 patients will experience some prominence of the metal over the shin, or an ache (especially in cold weather). Plate and screw removal can easily be performed in this case
The metal plates are made of stainless steel, which may trigger walk-through metal detectors, especially in more sensitive security systems.

Newer scanners (millimetre wave or body scanners) often detect the implant visually instead of relying solely on metal detection, so alarms may be less common than in the past.
This will depend upon what time of day the surgery is performed, and whether you have had additional procedures performed. If your surgery is in the morning, you will may go home the same day, but it is common to require a single night stay in hospital.
The first few days can be a bit uncomfortable, but you will be discharged with appropriate pain relief. The quadriceps muscles often go to sleep after the surgery, and the key to the early recovery is getting them contracting again. This will allow you to start weaning off crutches, and returning towards walking unaided. The knee will be swollen, and can remain so for a few weeks. This is normal. You will be required to wear a splint on the knee when walking for the first 3 weeks whilst the bone is starting to heal. You can remove the splint when not walking, and bend the knee as able.

You will be seen for a wound check at two weeks, and a follow-up clinic appointment will be arranged for 6-8 weeks following the surgery, with an x-ray to assess bone healing.

The key to successful recovery is engagement in the post-operative physiotherapy programme. This is a structured, evidence-based rehabilitation regiment that ensures that the muscles and knee control are restored after surgery, to allow you to ultimately return to activities of your choosing. This must be guided by a qualified physiotherapist. An outline of the rehabilitation timeline and goals can be found here.
Regards returning to work or studies, I advise to return when ‘no longer distracted by either the pain or pain killers’. If you have an office or home based job, this can be as early as one or two weeks. For more physically demanding jobs, return to work can take longer, but you can be provided with an appropriate fitness to work (sick) note for the period.

With regards to returning to activities, this will be dictated by how the knee is recovering with physio. Driving can normally be resumed by approximately 4-6 weeks. I advise you inform your car insurer prior to doing so. Details on returning to sporting activities can be found here. Full recovery is approximately 6 months.

What are the potential risks?

Tibial tuberosity osteotomy (TTO) is generally a safe and effective procedure. However, like all surgeries, it comes with risk. Every effort will be made to minimise these risks, but to allow this it is important that you mention any health issues at the pre-operative assessment. Below is a breakdown of the risks by frequency and approximate percentages, based on medical literature and clinical studies. Mr Smith will speak to you in detail about these prior to any surgery.

Risk	Description
Pain and swelling	Localised pain and swelling around the osteotomy site (5–10%)
Stiffness	Reduced knee movement, often temporary and improved with physiotherapy (5–10%)
Numbness or altered sensation	Temporary nerve irritation around incision area (5–10%)
Wound infection (superficial)	Minor infection treated with oral antibiotics (1–5%)
Hardware discomfort	Screw or plate irritation requiring removal (5–20%)
Delayed bone healing	Prolonged recovery if osteotomy takes longer to heal (up to 10%)
Deep infection	Requires surgical washout and IV antibiotics (0.1–0.5%)
Blood clot (Deep vein thrombosis/Pulmonary embolus/heart attack/stroke)	Risk due to post-op immobility (0.5–1%). You may be prescribed Aspirin after the surgery to reduce this risk
Non-union	Failure of the bone to heal, possibly requiring revision surgery (0.5–1%)
Re-displacement of the tuberosity	Can lead to altered patellar mechanics (0.5–1%)
Over- or under-correction	May result in persistent malalignment or patellar tracking issues (0.5–1%)
Fracture	Extension of the osteotomy causing tibial or patellar fracture (<0.1%)
Permanent nerve damage	Very rare injury to peripheral nerves causing persistent numbness or weakness (<0.1%)
Complex Regional Pain Syndrome (CRPS)	Chronic, disproportionate pain and dysfunction (<0.1%)
Anaesthetic complication	Serious reaction to anaesthesia including cardiac or respiratory events (<0.1%)
Hardware removal	Many patients eventually require screw or plate removal due to discomfort (up to 20%)
Residual anterior knee pain	Pain may persist despite surgical realignment (10–20%)
Arthritis progression	Underlying patellofemoral arthritis may continue over time
Failure to resolve instability	In cases performed for patellar instability, recurrence may still occur (<1%)
Patella baja	Low-riding patella after healing may affect knee mechanics and cause discomfort

When performed for patella instability and combined with other procedures, redislocation is rare (<1%). For anterior knee pain, the success is dependent upon whether there are any underlying arthritic changes, and the degree of soft tissue inflammation/impingement. For individuals with no arthritic change, pain relief is usually significant and often improves quickly after the surgery. Mr Smith is involved in ongoing research into the outcomes of surgery.
Please contact the hospital where your surgery was performed, and they will easily be able to get in contact with Mr Smith on your behalf.

Tibial tuberosity osteotomy (TTO) is an operation that is used to treat patella alta (high riding patella), which is associated with two main conditions: patellofemoral instability and anterior knee pain (due to lateral patella tendon conflict see here - link). It involves detaching the patella tendon attachment to the tibia with a block of bone, moving is down (distalising) and fixing it with a metal plate and screws. This brings the patella (kneecap) down to sit within the groove on the front of the femur. For stabilisation surgery, it is usually combined with additional procedures (trochleoplasty or MPFL reconstruction) at the same time.
Prior to considering surgical reconstruction, patients must complete a course of physiotherapy to strengthen the core, gluteal and quadriceps muscles that allow normal knee function and stabilise the patella. Bracing or taping can sometimes help stabilise the patella, and improve knee pain.
The surgery will be explained to you by Mr Smith in clinic, the alternatives, likely recovery period and any associated risks discussed. You will have a pre-operative clinic appointment to ensure that you are safe for surgery, and that there is no aspect of your health that can be optimised prior to having surgery. You will be informed at this stage when to stop any regular medications, and what time you can eat and drink until prior to the surgery.

On the day of surgery you will see Mr Smith and the anaesthetist prior to the surgery, to ensure that all questions have been addressed. The consent form will be checked with you, and the correct leg marked. You will often see a physiotherapist prior to your surgery also.
The procedure is usually performed under a general anaesthetic (fully asleep), with a nerve block in the thigh for pain relief.

You will be given antibiotics into the vein at the time of surgery to reduce the risk of infection.

An incision is made on the outer side of the lower leg, and the muscle carefully retracted backwards to expose the side of the tibia. The patella tendon and soft tissues are protected.

The attachment of the tendon to the bone is removed with a block of bone (about the size of a domino). This ‘domino’ is then moved down by a calculated amount, and fixed with a metal plate and screws.

The incisions are then washed with sterile water, and closed with stitch that absorbs. Adherent dressings are applied, with a bandage over the top.

The knee is placed in a splint for 3 weeks, but this is only worn when walking and can be removed at other times.
The surgery takes under an hour to perform. Often it is combined with a trochleoplasty or MPFL reconstruction, which will increase the surgical time.
For the majority of patients the metalwork does not cause a problem and will stay in. Approximately 1 in 5 patients will experience some prominence of the metal over the shin, or an ache (especially in cold weather). Plate and screw removal can easily be performed in this case
The metal plates are made of stainless steel, which may trigger walk-through metal detectors, especially in more sensitive security systems.

Newer scanners (millimetre wave or body scanners) often detect the implant visually instead of relying solely on metal detection, so alarms may be less common than in the past.
This will depend upon what time of day the surgery is performed, and whether you have had additional procedures performed. If your surgery is in the morning, you will may go home the same day, but it is common to require a single night stay in hospital.
The first few days can be a bit uncomfortable, but you will be discharged with appropriate pain relief. The quadriceps muscles often go to sleep after the surgery, and the key to the early recovery is getting them contracting again. This will allow you to start weaning off crutches, and returning towards walking unaided. The knee will be swollen, and can remain so for a few weeks. This is normal. You will be required to wear a splint on the knee when walking for the first 3 weeks whilst the bone is starting to heal. You can remove the splint when not walking, and bend the knee as able.

You will be seen for a wound check at two weeks, and a follow-up clinic appointment will be arranged for 6-8 weeks following the surgery, with an x-ray to assess bone healing.

The key to successful recovery is engagement in the post-operative physiotherapy programme. This is a structured, evidence-based rehabilitation regiment that ensures that the muscles and knee control are restored after surgery, to allow you to ultimately return to activities of your choosing. This must be guided by a qualified physiotherapist. An outline of the rehabilitation timeline and goals can be found here.
Regards returning to work or studies, I advise to return when ‘no longer distracted by either the pain or pain killers’. If you have an office or home based job, this can be as early as one or two weeks. For more physically demanding jobs, return to work can take longer, but you can be provided with an appropriate fitness to work (sick) note for the period.

With regards to returning to activities, this will be dictated by how the knee is recovering with physio. Driving can normally be resumed by approximately 4-6 weeks. I advise you inform your car insurer prior to doing so. Details on returning to sporting activities can be found here. Full recovery is approximately 6 months.

What are the potential risks?

Risk	Description
Pain and swelling	Localised pain and swelling around the osteotomy site (5–10%)
Stiffness	Reduced knee movement, often temporary and improved with physiotherapy (5–10%)
Numbness or altered sensation	Temporary nerve irritation around incision area (5–10%)
Wound infection (superficial)	Minor infection treated with oral antibiotics (1–5%)
Hardware discomfort	Screw or plate irritation requiring removal (5–20%)
Delayed bone healing	Prolonged recovery if osteotomy takes longer to heal (up to 10%)
Deep infection	Requires surgical washout and IV antibiotics (0.1–0.5%)
Blood clot (Deep vein thrombosis/Pulmonary embolus/heart attack/stroke)	Risk due to post-op immobility (0.5–1%). You may be prescribed Aspirin after the surgery to reduce this risk
Non-union	Failure of the bone to heal, possibly requiring revision surgery (0.5–1%)
Re-displacement of the tuberosity	Can lead to altered patellar mechanics (0.5–1%)
Over- or under-correction	May result in persistent malalignment or patellar tracking issues (0.5–1%)
Fracture	Extension of the osteotomy causing tibial or patellar fracture (<0.1%)
Permanent nerve damage	Very rare injury to peripheral nerves causing persistent numbness or weakness (<0.1%)
Complex Regional Pain Syndrome (CRPS)	Chronic, disproportionate pain and dysfunction (<0.1%)
Anaesthetic complication	Serious reaction to anaesthesia including cardiac or respiratory events (<0.1%)
Hardware removal	Many patients eventually require screw or plate removal due to discomfort (up to 20%)
Residual anterior knee pain	Pain may persist despite surgical realignment (10–20%)
Arthritis progression	Underlying patellofemoral arthritis may continue over time
Failure to resolve instability	In cases performed for patellar instability, recurrence may still occur (<1%)
Patella baja	Low-riding patella after healing may affect knee mechanics and cause discomfort

When performed for patella instability and combined with other procedures, redislocation is rare (<1%). For anterior knee pain, the success is dependent upon whether there are any underlying arthritic changes, and the degree of soft tissue inflammation/impingement. For individuals with no arthritic change, pain relief is usually significant and often improves quickly after the surgery. Mr Smith is involved in ongoing research into the outcomes of surgery.
Please contact the hospital where your surgery was performed, and they will easily be able to get in contact with Mr Smith on your behalf.

Tibial tuberosity osteotomy (TTO)

Deciding whether to have knee surgery can feel overwhelming. This guide will help you understand your knee surgery options, benefits, risks, and recovery so you can make an informed decision about the right treatment for your condition.

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