Trochleoplasty

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.

Trochleoplasty is a highly specialised surgical procedure, performed by relatively few knee surgeons. It is an operation to treat recurrent patellofemoral instability (kneecap dislocations). It is indicated when the groove on the front of the femur (trochlea) that the patella sits in does not develop fully, and is instead a bump rather than a groove. This makes the knee cap very unstable, and prone to dislocate. This is call severe trochlea dysplasia.
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.

Living with your symptoms, and avoiding activities that cause your instability is an option, but evidence shows that people with recurrent dislocations have a poor quality of life.

Medial patellofemoral ligament (MPFL) reconstruction may be an alternative in more moderate cases, where the trochlea is flat, rather that a bump.
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.

The surgery is performed with a tourniquet on the thigh, which temporarily stops the blood to the area, increasing surgical visualisation and minimising bleeding. This may leave you with a sore thigh for a couple of days following the surgery.

An incision is made on the outer side of the knee, and the patella is moved to one side to allow access.

Using osteotomes (bone chisels), the cartilage overlying the trochlea (groove) is carefully raised from the underlying bone. The bony bump is then excised, and a groove sculpted in the bone. The cartilage flap is then laid into the new groove, and fixed in place.

The soft tissues on the inner side are then re-tensioned to further stabilise the patella within the groove (modified Insall procedure).

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 surgery takes approximately an hour to perform. Often it is combined with a tibial tuberosity osteotomy, which will increase the surgical time.
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.

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 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	Expected in the early postoperative period; improves with rest and rehab (5–10%)
Knee stiffness	Reduced motion post-op; often resolves with physiotherapy (5–10%)
Numbness or altered sensation	Due to nerve irritation near the incision (5–10%)
Wound infection (superficial)	Managed with oral antibiotics (1–5%)
Patellofemoral crepitus	Grinding or clicking from joint changes or scar tissue (5–10%)
Deep joint infection	Serious infection requiring surgery and IV antibiotics (0.1–0.5%)
Blood clot (Deep vein thrombosis/Pulmonary embolus/heart attack/stroke)	Risk due to limited mobility after surgery (0.5–1%). You may be prescribed Aspirin after the surgery to reduce this risk
Over- or under-correction	Can lead to persistent symptoms or new patellar tracking issues (0.5–1%)
Residual instability	Despite surgery, the patella may still be prone to subluxation/dislocation (0.5–1%)
Cartilage damage	Injury to surrounding joint cartilage during reshaping; may contribute to arthritis (0.5–1%)
Flap loss or displacement	The reshaped trochlear bone flap may not heal or may shift, causing instability or pain (0.5–1%)
Permanent nerve damage	Rare injury to peripheral nerves causing persistent numbness or weakness (<0.1%)
Complex Regional Pain Syndrome (CRPS)	Chronic, disabling pain response to surgery (<0.1%)
Anaesthetic complication	Includes severe allergic or respiratory reactions (<0.1%)
Patellofemoral arthritis	Degeneration of joint cartilage over time; may be accelerated by surgery
Persistent anterior knee pain	May remain despite improved stability (up to 10%)
Recurrent instability	Rare but may occur despite surgery, especially in complex cases (5–10%)
Loss of performance	Athletes may not return to pre-injury levels of activity (up to 30%)

Trochleoplasty with the described technique has excellent outcomes, with over 90% patient satisfaction, and low re-dislocation rates.
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.

Trochleoplasty is a highly specialised surgical procedure, performed by relatively few knee surgeons. It is an operation to treat recurrent patellofemoral instability (kneecap dislocations). It is indicated when the groove on the front of the femur (trochlea) that the patella sits in does not develop fully, and is instead a bump rather than a groove. This makes the knee cap very unstable, and prone to dislocate. This is call severe trochlea dysplasia.
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.

Living with your symptoms, and avoiding activities that cause your instability is an option, but evidence shows that people with recurrent dislocations have a poor quality of life.

Medial patellofemoral ligament (MPFL) reconstruction may be an alternative in more moderate cases, where the trochlea is flat, rather that a bump.
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.

The surgery is performed with a tourniquet on the thigh, which temporarily stops the blood to the area, increasing surgical visualisation and minimising bleeding. This may leave you with a sore thigh for a couple of days following the surgery.

An incision is made on the outer side of the knee, and the patella is moved to one side to allow access.

Using osteotomes (bone chisels), the cartilage overlying the trochlea (groove) is carefully raised from the underlying bone. The bony bump is then excised, and a groove sculpted in the bone. The cartilage flap is then laid into the new groove, and fixed in place.

The soft tissues on the inner side are then re-tensioned to further stabilise the patella within the groove (modified Insall procedure).

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 surgery takes approximately an hour to perform. Often it is combined with a tibial tuberosity osteotomy, which will increase the surgical time.
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.

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 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	Expected in the early postoperative period; improves with rest and rehab (5–10%)
Knee stiffness	Reduced motion post-op; often resolves with physiotherapy (5–10%)
Numbness or altered sensation	Due to nerve irritation near the incision (5–10%)
Wound infection (superficial)	Managed with oral antibiotics (1–5%)
Patellofemoral crepitus	Grinding or clicking from joint changes or scar tissue (5–10%)
Deep joint infection	Serious infection requiring surgery and IV antibiotics (0.1–0.5%)
Blood clot (Deep vein thrombosis/Pulmonary embolus/heart attack/stroke)	Risk due to limited mobility after surgery (0.5–1%). You may be prescribed Aspirin after the surgery to reduce this risk
Over- or under-correction	Can lead to persistent symptoms or new patellar tracking issues (0.5–1%)
Residual instability	Despite surgery, the patella may still be prone to subluxation/dislocation (0.5–1%)
Cartilage damage	Injury to surrounding joint cartilage during reshaping; may contribute to arthritis (0.5–1%)
Flap loss or displacement	The reshaped trochlear bone flap may not heal or may shift, causing instability or pain (0.5–1%)
Permanent nerve damage	Rare injury to peripheral nerves causing persistent numbness or weakness (<0.1%)
Complex Regional Pain Syndrome (CRPS)	Chronic, disabling pain response to surgery (<0.1%)
Anaesthetic complication	Includes severe allergic or respiratory reactions (<0.1%)
Patellofemoral arthritis	Degeneration of joint cartilage over time; may be accelerated by surgery
Persistent anterior knee pain	May remain despite improved stability (up to 10%)
Recurrent instability	Rare but may occur despite surgery, especially in complex cases (5–10%)
Loss of performance	Athletes may not return to pre-injury levels of activity (up to 30%)

Trochleoplasty with the described technique has excellent outcomes, with over 90% patient satisfaction, and low re-dislocation rates.
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.

Trochleoplasty

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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