Osteotomy around the knee is an operation to alter the alignment of the leg.
It is mainly used in the treatment of arthritis in young patients to avoid knee replacement but also has a role in the treatment of complex knee instability.
High Tibial Osteotomy
This operation is aimed at realigning the leg so as to reduce the forces of body weight that go through the inside (medial aspect) of the knee that has and transfer them more to the undamaged normal outside (lateral) compartment of the knee.
The operation is particularly suited for young and very active patients who wish to avoid artificial joint replacement and who have a normal lateral compartment of their knee without any significant wear and tear arthritis.
Most patients get good pain relief from an osteotomy although often the pain is relieved rather than abolished but it allows a much higher level of functioning.
Activities of daily living are usually much less painful. However, as the knee arthritis still exists it can still hurt, particularly if overloaded with a lot of impact activities.
One role of an osteotomy is to avoid/delay the need for a total knee replacement and thus hopefully avoid the situation where a second TKR is required.
The major advantage of an osteotomy over joint replacement is that you still have a natural knee, no bridges have been burnt; you have fewer restrictions than after a knee replacement, without any specific restrictions, including running, if possible.
If the knee deteriorates and the wear and the osteoarthritis progresses then it is possible to have a Knee Replacement.
This involves cutting the tibia (osteotomy) and either removing a wedge of bone (closing wedge) or opening the osteotomy (opening wedge) and filling it with a wedge of bone or bone like substance.
This allows correction of the angle of the lower leg at the knee. In effect, the tibia is therefore fractured and this “fracture” is stabilised with a staple or plate.
The surgery is usually performed under General Anaesthesia and usually requires an overnight stay in hospital. In addition to keyhole surgery incision there is a longer incision on the inside or outside of the calf depending on the type of osteotomy.
Post-operatively, the knee is immobilised in a splint that keeps the knee straight. This is ‘weaned’ off by six weeks post-operatively.
No weight-bearing is allowed in the first few weeks following surgery and crutches are required for a minimum of six weeks and most patients are fully off crutches by eight weeks following surgery.
Patients are unable to drive for six to eight weeks following surgery.
As the operation effectively creates a fracture of the tibia it requires about 3 months to heal and so the recovery time takes this long until most patients feel themselves to be ‘recovered from surgery’.
There is significant improvement in pain ( ie reduced by approximately 80%) in approximately 90% of patients. It takes almost a year for the effect of the surgery to reach the maximal benefit.
This benefit last for more than 10 years in the majority of patients. If pain recurs, a knee replacement might be necessary
Osteotomy is a routine operation but no operation is without risk.
The major risks are :
- Infection Deep bony infection is very rare (<1%) but if it occurred and was untreated then serious problems could occur.
- Damage to blood vessels nerves These risks are very rare but potentially very serious.
- Risk to life. This is in the order of 1-2 in 1000 mainly from anaesthetic problems or blood clots in the legs that travel to the lungs, (pulmonary embolus).
- Many other complications are possible, most of which are treatable but in general the risk of sustaining a complication that leaves a patient significantly worse off in the long term is around 2%.
Distal Femoral Osteotomy
This is an operation that is used to treat patients who have valgus alignment of their legs (‘knock kneed’) with pain and degeneration on the outside (lateral) compartment but with a normal inside (medial) compartment.
This situation is relatively rare as most arthritis affects the medial compartment of the knee.
The principles, surgery, rehabilitation and risks of distal femoral osteotomy are largely the same as for a high tibal osteotomy except that the thigh bone (femur) is the bone that is cut.