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Medial patellofemoral ligament (MPFL) reconstruction

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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.

  • Medial patellofemoral ligament (MPFL) reconstruction is an operation to treat recurrent patellofemoral instability (kneecap dislocations). It involves reconstruction/replacement of the ligament on the medial (inner) side of the knee that runs between the patella and the femur, which is torn or stretched with a patella dislocation. This ligament stabilises the kneecap, preventing it from dislocating.

  • 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.

  • 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.

    ​

    • The ligament is reconstructed by using one of the hamstrings tendons from the same leg as a graft. A small incision is made over the top of the shin to harvest this tendon. This area is injected with local anaesthetic to reduce pain.

    ​

    • The surgery is arthroscopically (keyhole) assisted. This allows the position of the patella within the groove to be assessed before and after the reconstruction.

    ​

    • A small incision is made alongside the patella and over the inner side of the knee. 

    ​

    • Using x-ray to ensue correct positioning, a tunnel is drilled across both the patella and the femur. The graft is then passed into each tunnel and secured (with a button on the patella and a screw on the femur).

    ​

    • The position of the patella checked arthroscopically to ensure that it is stable and tracking centrally within the groove.

    ​

    • 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 under 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. If your surgery is in the morning, you will usually go home the same day. If later on, you may 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 seen for a wound check at two weeks, and a follow-up clinic appointment will be arranged for 6-8 weeks following the surgery.

    ​

    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.

  • MPFL reconstruction 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
    Knee stiffness
    Reduced range of motion post-op; may require physiotherapy (5–10%)
    Ongoing pain
    Pain around the knee or graft site may persist (5–10%)
    Swelling
    Post-operative effusion usually resolves (5–10%)
    Wound infection (superficial)
    Local skin infection, treated with antibiotics (1–5%)
    Numbness (around incision)
    Temporary nerve irritation causing numbness (5–10%)
    Graft site tenderness
    Tenderness or discomfort at graft harvest site, if autograft used (5–10%)
    Deep joint infection
    Infection inside the knee joint requiring washout and antibiotics (0.1–0.5%)
    Blood clot (Deep vein thrombosis/Pulmonary embolus/heart attack/stroke)
    Clot formation risk due to immobility (0.5–1%). You may be prescribed Aspirin after the surgery to reduce this risk
    Graft failure or loosening
    Recurrent instability due to graft stretching or failure (0.5–1%)
    Hardware irritation
    Discomfort from screws or anchors that may require removal (0.5–1%)
    Recurrent patellar instability
    Persistence or recurrence of patellar dislocation (<1%). Associated with hyper mobility and pregnancy.
    Nerve or vessel injury
    Injury to nearby nerves or blood vessels (<0.1%)
    Complex Regional Pain Syndrome (CRPS)
    Chronic pain disorder after surgery (<0.1%)
    Anaesthetic complication
    Serious allergic or cardiorespiratory reactions (<0.1%)
    Fracture
    Patellar or femoral fracture during surgery (<0.1%)
    Residual instability
    Persistent sensation of patella giving way despite surgery (up to 10%)
    Loss of motion
    Long-term stiffness or loss of knee flexion (5–10%)
    Graft stretching or rupture
    Late failure of reconstructed ligament requiring revision (up to 10%)
    Patellofemoral arthritis
    Development of arthritis in the patellofemoral joint over years post-surgery
    Anterior knee pain
    Chronic pain around the kneecap, sometimes related to graft or hardware

  • In the right patient, MPFL reconstruction is a successful operation in terms of stabilising the kneecap, with redislocation rates of less than 1%. The psychological ‘trust’ within the knee can take a long time to regain.

  • 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.

  • Medial patellofemoral ligament (MPFL) reconstruction is an operation to treat recurrent patellofemoral instability (kneecap dislocations). It involves reconstruction/replacement of the ligament on the medial (inner) side of the knee that runs between the patella and the femur, which is torn or stretched with a patella dislocation. This ligament stabilises the kneecap, preventing it from dislocating.

  • 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.

  • 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.

    ​

    • The ligament is reconstructed by using one of the hamstrings tendons from the same leg as a graft. A small incision is made over the top of the shin to harvest this tendon. This area is injected with local anaesthetic to reduce pain.

    ​

    • The surgery is arthroscopically (keyhole) assisted. This allows the position of the patella within the groove to be assessed before and after the reconstruction.

    ​

    • A small incision is made alongside the patella and over the inner side of the knee. 

    ​

    • Using x-ray to ensue correct positioning, a tunnel is drilled across both the patella and the femur. The graft is then passed into each tunnel and secured (with a button on the patella and a screw on the femur).

    ​

    • The position of the patella checked arthroscopically to ensure that it is stable and tracking centrally within the groove.

    ​

    • 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 under 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. If your surgery is in the morning, you will usually go home the same day. If later on, you may 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 seen for a wound check at two weeks, and a follow-up clinic appointment will be arranged for 6-8 weeks following the surgery.

    ​

    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.

  • MPFL reconstruction 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
    Knee stiffness
    Reduced range of motion post-op; may require physiotherapy (5–10%)
    Ongoing pain
    Pain around the knee or graft site may persist (5–10%)
    Swelling
    Post-operative effusion usually resolves (5–10%)
    Wound infection (superficial)
    Local skin infection, treated with antibiotics (1–5%)
    Numbness (around incision)
    Temporary nerve irritation causing numbness (5–10%)
    Graft site tenderness
    Tenderness or discomfort at graft harvest site, if autograft used (5–10%)
    Deep joint infection
    Infection inside the knee joint requiring washout and antibiotics (0.1–0.5%)
    Blood clot (Deep vein thrombosis/Pulmonary embolus/heart attack/stroke)
    Clot formation risk due to immobility (0.5–1%). You may be prescribed Aspirin after the surgery to reduce this risk
    Graft failure or loosening
    Recurrent instability due to graft stretching or failure (0.5–1%)
    Hardware irritation
    Discomfort from screws or anchors that may require removal (0.5–1%)
    Recurrent patellar instability
    Persistence or recurrence of patellar dislocation (<1%). Associated with hyper mobility and pregnancy.
    Nerve or vessel injury
    Injury to nearby nerves or blood vessels (<0.1%)
    Complex Regional Pain Syndrome (CRPS)
    Chronic pain disorder after surgery (<0.1%)
    Anaesthetic complication
    Serious allergic or cardiorespiratory reactions (<0.1%)
    Fracture
    Patellar or femoral fracture during surgery (<0.1%)
    Residual instability
    Persistent sensation of patella giving way despite surgery (up to 10%)
    Loss of motion
    Long-term stiffness or loss of knee flexion (5–10%)
    Graft stretching or rupture
    Late failure of reconstructed ligament requiring revision (up to 10%)
    Patellofemoral arthritis
    Development of arthritis in the patellofemoral joint over years post-surgery
    Anterior knee pain
    Chronic pain around the kneecap, sometimes related to graft or hardware

  • In the right patient, MPFL reconstruction is a successful operation in terms of stabilising the kneecap, with redislocation rates of less than 1%. The psychological ‘trust’ within the knee can take a long time to regain.

  • 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.

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