Overall lifetime risk of requiring knee revision surgery amongst all patients is 5% but we know that younger patients ( <70) will use their knees for longer and often more vigorously which puts this group at higher risk of wearing out their knee and requiring revision (redo) surgery.
Patients will usually know when their knee is beginning to wear out or start becoming loose. The symptoms are classically of “startup pain” just as you rise from a seated position and take the first few steps, and this usually settles to a degree as walking continues. This pain can be in the knee itself, or be referred to the thigh or shinbone depending on which component is most problematic. If you begin to detect any of these symptoms it’s well worth arranging an xray via your GP to evaluate for a loose prosthesis or alternatively arranging to be seen by a specialist such as Mr Barksfield.
What does Revision Surgery Involve?
Surgery for loose total knee replacements is very varied and a bespoke surgery package is developed for each individual patient based upon the problems they have with their knee. Surgery usually involves revision of both components often using more complex types of prosthesis to account for bone loss.
Most revisions will be performed because the components have worn out and become loose and this is usually done in a single operation. Recovery often takes a little longer than the first operation, as the procedure often takes a little longer and requires a larger exposure (cut in the skin).
Occasionally it is necessary to perform revisions for infection and one several approaches will be used :
- Debridement and implant retention (DAIR)
This technique was pioneered in Oxford and is usually performed for infections that occur acutely and present within 8 weeks within the onset of infection. The knee joint is washed out, infected tissue removed and the polyethylene insert changed to attempt to eradicate the infection. This is then supplemented by a long course of antibiotics. This is the least invasive form of revision for infection with success in 75% of cases.
- Single stage revision
Similar to DAIR, but all components are removed and new components implanted within the same sitting. This is also supplemented with a long course of antibiotic therapy with success rates of 85% of cases.
- Two stage revision
The most rigorous form of revision for infection requires removal of all infected tissue and implants and leaves you without a knee until we are confident all infection has been eradicated (a spacer made from cement is temporarily inserted). At an interval of between 6 and 12 weeks of antibiotic therapy a new knee prosthesis is implanted. This has the best chances of eradication of infection (90%) but is a bigger procedure to go through in terms of strain on the body.
Recovery Following Revision Knee Surgery
Recovery following revision knee surgery often takes a little longer than your first knee replacement and this is a reflection of the increased complexity of the surgery involved. The process will be guided by the physiotherapy team under the close supervision of your surgeon. You will be given exercises to improve the range of movement of the joint and strengthen the muscles around the knee. Activities such as hydrotherapy and cycling can be helpful to improve the function of the knee and restore your mobility.