An Osteotomy, of any kind, is an operation where a bone is cut, usually realigned in some way, and then re-fixed to heal in its new configuration.
The Femoral Osteotomies described here are, as the name suggests, osteotomies carried out on the Femur (thigh bone) to correct a number of conditions.
Some operations are specifically named, others are referred to by the condition they fix, such as S.U.F.E. (Slipped Upper Femoral Epiphysis).
The most common problem requiring a femoral osteotomy is where the femur is abnormally twisted causing the foot to be turned either inwards or outwards.
This “abnormal anteversion” is corrected by a rotation osteotomy, guided for precision by pre-operative CT scans. The femur is cut, rotated to the correct angle, then fixed in place with plates and screws.
After a year the bone will have healed, and the plate and screws are removed.
Varus osteotomy of the femur is an operation where the shaft of the femur is divided just below the neck. The angle between the neck and the shaft is reduced and this can produce better cover of the most deformable part of the femoral head, so encouraging circular remodelling of the area affected by Perthes’ disease.
It is an operation of proven effectiveness and it is relatively simple to do. A plate with screw fixation is required and this is removed approximately a year later.
Perthes’ disease very frequently results in some shortening of the affected limb, and varus osteotomy further shortens it. A proportion of patients who have had a varus osteotomy carried out will need the operation reversed – a valgus osteotomy – once the head has healed and if the leg length discrepancy and accompanying limited movement is a problem. The metalwork will also need to be removed a year after the valgus osteotomy.
In some children, whose femoral head is not sufficiently round and where it will not centre deeply in the socket in abduction (outward movement of the leg), varus osteotomy is inappropriate, as is pelvic osteotomy.
In these patients where movement is limited and where the surgeon appreciates that the remodelled head will be significantly out of round, a valgus osteotomy can restore movement, restore leg length and generally improve the function of the hip.
This is a corrective osteotomy where the neck shaft angle is returned to normal. A blade plate, with one part seated into the neck of the femur and the side plate on the outside of the femur is used to provide the necessary angular correction.
The osteotomy will probably take three or four months to heal in adults, but less in children under 10. Protected weightbearing is advised for at least six to eight weeks. The plate will need to be removed at a year afterwards.
There is also evidence within the peer reviewed orthopaedic literature that because the hip moves more freely after a valgus osteotomy, the femoral head gradually rounds off over many years afterwards. Such patients are, however, sometimes left with some shallowness of the hip socket (residual acetabular dysplasia).
Occasionally patients present where there is a very complex abnormality of the proximal femur with a very short neck, a very high trochanter and such disorganisation that none of the other operations described would provide for a restoration of normal anatomy.
These patients can sometimes be helped by a modified Wagner double osteotomy of the femur. This operation, which can look a bit like a jigsaw puzzle at the planning stage, can be very effective in producing reasonably normal anatomy with a significant improvement in the function of the hip joint.
I have experience of about 30 similar operations and I am not yet aware of any of them having failed. Two of them, however, required re-exploration, as some of the bone pieces had come adrift.
This condition affects the young while their bones are still growing. It occurs where the growth plate at the upper end of the femur de-couples and the head of the femur slips backwards and downwards. The leg tends to be in a position of external rotation (particularly when sitting).
The vast majority of cases can be treated successfully in the first instance by passing a single threaded screw across the growth plate to prevent further slippage, and to encourage fusion of the growth plate.
These young patients present with the leg turned outwards, but over the following 12 to 18 months a large majority will remodel so that they have near normal ranges of hip rotation and will not need any further treatment beyond removal of the screw.
Some surgeons do not believe that removal of the screw itself is even required in all cases. I tend to advise the screw be removed if possible, as it may help if the patient has any residual symptoms at all and furthermore if any further hip surgery at any time of life is required to this area, the removal of the screw will facilitate it. Later attempts to remove the screw after a number of decades may prove to be very difficult.
Patients who still have significant bony deformity at 18 months and more after the initial presentation, may like to consider a reconstructive operation of the upper end of the femur.
This is a complex operation (Imhauser’s, published in Germany in 1977). It involves insertion of a blade plate along the track of the neck of the femur, reaching across the growth plate in some circumstances. By putting the blade plate in at a particular angle of flexion and following a complete anterior release of the capsule and division of the bone just above the lesser trochanter, it is usually possible to get the head of the femur back up into the socket, restore a significant amount of the lost leg length, abduction (outward movements) and rotation.
Due to the complex nature of the operation, the bone surfaces are not always a particularly good fit upon one another. The osteotomy may take three or four months to heal and post-operative weightbearing is likely to be significantly restricted for a large proportion of that time.
Osteotomy of the femur is usually a reasonably stable operation and partial weightbearing is usually possible, and to be encouraged, in the immediate aftermath of the operation.
It is important, particularly for teenagers (where in one year there was a 35% re-operation rate), to realise that although the plates used give the impression of great structural strength, they are not capable of taking much more than half body weight without risk of bending, breaking or the screws being pulled out.
From the very first day, physiotherapists can assist with flexion, extension, abduction and adduction. Gradually the patient will be able to become completely independent in respect of all of these movements.
As patients are advised to only partially bear weight in the short-term following these operations, the abductor muscles on the outside of the upper thigh and buttock tend to weaken. Specific abduction exercises against gravity are to be encouraged in such patients from the very earliest date that they are possible.
From two weeks after the operation, if they can get themselves in and out of a pool with the assistance of a helpful friend or relative, regular swimming and walking in the water (at about chest level) is encouraged.
From approximately three to four months after the operation they should be able to do their own exercise programme entirely independently of a physiotherapist.
Following a femoral osteotomy alone, the vast majority of patients will be fully rehabilitated within six months.
Over the years, I have had experience of approximately 70 cases similar to those referred to in this section, all of whom would have needed joint replacement had this reconstructive work not been performed. So far, I am aware of only two failures out of that group of patients.