Treatment - How can I help

Extensor Mechanism Realignment

Other popular names


Who does it affect?

Anyone.  In some patients this tendency is greater than others due to their own individual body shape and bony anatomy.  In others it may be due to injury.

Why does it happen?

Disorders of the patello-femoral joint, that is the articulation between the undersurface of the patella and the front of the femur (the trochlea groove), are very common.

They can be broadly divided into two groups – patella instability and pain.  Patella instability is where the patella dislocates or subluxes (partially dislocates).

In everyone the pull of the quadriceps muscles tends to pull the patella laterally.  Some patients are pre-disposed to subluxation or dislocation and can dislocate their patella for the first time with less severe, and for some patients, even trivial trauma.  Some patients without such a pre-disposition can sustain a more severe injury that causes the patella to dislocate.


A combination of pain, swelling, instability and tenderness which may be localised or extended depending upon the injury.


The diagnosis is often clear with a knowledge of lateral dislocation of the patella followed by marked pain and swelling. On examination there is tenderness over the stretched MPFL.

After the pain and swelling of the acute injury has settled, abnormal lateral movement of the patella is often apparent and patients are often very apprehensive when the patella is moved laterally (patella apprehension).

An MRI scan is occasionally used to confirm the diagnosis and to identify any other injuries in the acutely painful and swollen knee following a dislocation.

Non-surgical treatment

All patients need a period of rest and rehabilitation following the acute injury.  This should include a program of physiotherapy to regain a full range of movement and improve muscle function around the knee.

Many patients are able to prevent further episodes of subluxation or dislocation by performing exercises taught though a physiotherapy programme aimed at improving the ability of the quadriceps, in particular, the function of the VMO (vastus medialis obliquitis) muscles to prevent patella dislocation.

Unfortunately some patients continue to experience patella instability symptoms despite a properly performed exercise programme and these patients can require surgery to prevent further episodes of dislocation.

Surgical treatment

This type of surgery, performed under general anaesthetic, usually involves altering the position of the tibial tuberosity to which the patella tendon is attached. This alters the angle of ‘pull’ of the quadriceps muscles on the patella for patients in whom this pull is likely to cause dislocation of the patella.

The operation involves an 8cm incision in addition to the arthroscopic incisions over the lateral aspect of the upper shin just below the knee. The tibial tubersoity is cut, moved medially and held in its new position with screws.

Post-surgery rehabilitation

You are likely to spend 1 or 2 nights in hospital.   Protection of the knee is required for up to 6 weeks and a rehabilitation programme for around 3 months.

The anaesthetic will wear off after approximately 6 hours.  Simple analgesia (pain killers) usually controls the pain and should be started before the anaesthetic has worn off. 

You will go home in a splint and on crutches. Take the splint off only for a bath or shower.  Carry out simple quadriceps tensioning exercises. Touch weight-bearing only. Keep the wound covered and clean and dry (leave the dressing alone).


All of these time parameters are minimum if progress is as expected.

Return to normal routine

Bathing and showering 

The wounds should be kept clean and dry until the wound has sealed. Showering is fine and the waterproof dressings can be changed afterwards. Bathing is best avoided until the wounds are sealed, typically 10 days after surgery.
In summary, whilst the wounds are wet - keep them dry and when the wounds are dry, you can get them wet!


Surgery is followed by a prolonged course of physiotherapy. This requires a commitment to undertake this rehabilitation in order to achieve the best possible result (at least half an hour per day for 6 months).  It is vitally important to stay within the post-operative activity restrictions an physiotherapy guidelines to avoid damaging stretching your reconstructed ligament.

Return to work

The timing of your return to work depends on the type of work and your access, however, the following is a general guide:


When you can walk without crutches or a limp and be in control of your vehicle (about 8 weeks).


No operation is without risk. Complications that can occur include:

These risks include:

All these risks are uncommon and in total, the chance of being worse off in the long term is about or less than 1%.

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