MEDIAL CLOSING-WEDGE DISTAL FEMORAL OSTEOTOMY
WHAT IS THE PROBLEM?
Like all joints, the knee is covered with cartilage, a slippery substance with no nerve endings that allows the joint to move freely and painlessly. This cartilage can wear for various reasons (excess weight, sequelae of a meniscectomy or a fracture…) exposing the underlying bone, which is rough and innervated; the joint gradually becomes stiff and painful. This is known as knee osteoarthritis or gonarthrosis.
WHAT IS FEMORAL KNEE VARIATION OSTEOTOMY BY INTERNAL CLOSURE?
Internal closure femoral varus osteotomy of the knee is an orthopedic surgical procedure used to treat certain knee problems, such as unicompartmental osteoarthritis (osteoarthritis affecting only one part of the knee), limb alignment deformities lower, or other conditions that cause abnormal loading on the knee.
Here is a detailed explanation of each term:
- Femoral Osteotomy : This is the surgical cutting of the femoral bone, which is the thigh bone.
Knee varisation : Varisation refers to an inward change in the alignment angle of the lower extremity. In the case of femoral varisation osteotomy of the knee, this procedure aims to correct a deviated alignment of the knee by straightening it slightly inwards.
Internal closure : This means that the procedure is performed internally, which usually involves incisions and tissue manipulations being made inside the surgical area, without resorting to a significant opening of the skin. Internal closure techniques may allow for faster recovery and fewer complications associated with open surgery.
Internal closure femoral varus osteotomy is a surgical procedure that involves cutting and realigning the thigh bone to correct a deviated knee alignment, and is performed by minimizing openings in the skin and external manipulations of tissues. This procedure aims to relieve pain and improve knee function in patients with certain orthopedic conditions.
WHEN SHOULD A DISTAL FEMORAL OSTEOTOMY BE CONSIDERED?
A distal femoral osteotomy is indicated when only the lateral femorotibial compartment of the knee is affected by osteoarthritis. A knock-knee deformity of the femur (genu valgum) can aggravate this osteoarthritis, as it increases the load on the lateral compartment of the knee and accelerates cartilage wear.
A distal femoral osteotomy is only indicated when the cartilage in the lateral part of the knee is not completely worn in patients under 60 who are considered too young to undergo a knee replacement.
This procedure consists in straightening the deformity of the femur to transfer the mechanical load to the medial part of the knee where the cartilage is not worn thus relieving the pain in the lateral part of the knee, slowing the progression of osteoarthritis, and ultimately delaying the need for a knee replacement.
This procedure is sometimes proposed in the absence of significant pain in relatively young patients with severe lateral osteoarthritis. The problem with this type of osteoarthritis is the risk of it becoming painful once the cartilage wear is too severe and a distal femoral osteotomy is no longer possible. This procedure may, therefore, be proposed in young patients to slow the progression of the osteoarthritis and avoid a knee replacement, even in the absence of pain.
BEFORE THE OPERATION
A distal femoral osteotomy requires an operation. The realignment necessary is determined during a scheduled consultation based on x-rays of all the lower limbs (hip-knee-ankle x-ray or EOS scan).
Before the operation, a pre-anaesthesia consultation is conducted to check the patient is physically apt to undergo the operation and minimise the risk of postoperative complications.
THE OPERATION
The operation takes place in an operating theatre in compliance with strict standards of cleanliness and safety. The patient is placed supine on an operating table and a tourniquet is placed around the thigh. The operation lasts about 1 hour and can be carried out under general or spinal anaesthesia. The latter is a regional anaesthetic anaesthetising the lower part of the body (as with an epidural). The anaesthetist will decide on the most suitable anaesthetic together with the patient.
To perform a distal femoral osteotomy, an incision about 10 centimetres long on the lower, medial part of the thigh is necessary. Two cut lines are made in the femur and a wedge of bone is removed to realign the axis of the knee. The femur is then fixed with a plate.
AFTER THE OPERATION
A drain is inserted in the incision to prevent the formation of a haematoma.
After the operation, the knee is partially numbed with a nerve block to help improve postoperative pain management.
The effect lasts approximately 18 hours after the operation and can be prolonged with the insertion of a catheter in the thigh if the anaesthetist considers it necessary. Medication and ice on the knee also provide effective postoperative pain management.
After the operation, weight-bearing is not allowed on the leg operated on for 6 weeks and crutches must be used for walking.
Weight-bearing can then be resumed gradually. During this period, the knee can be mobilised during rehabilitation sessions. The knee may be immobilised in a brace while the bone heals.
The stay in hospital is often between 2 and 5 days.
The bone takes 2 to 3 months to heal, sometimes longer.
Several appointments are necessary to monitor the healing of the osteotomy.
The duration of medical leave depends on the patient’s occupation and is often between 2 and 4 months.
Driving can be resumed once weight-bearing is fully recovered. Sport can generally be resumed after 6 months.
Planning osteotomy lines (in red)
Femoral cutting guide
Final appearance with femur realignment
RISKS LINKED TO THE OPERATION
Unfortunately, zero risk does not exist in surgery. Any operation has its risks and limitations, which you must accept or not undergo the operation. However, if an operation is proposed, the surgeon and the anaesthetist consider that the expected benefits far outweigh the risk incurred.
Some risks, such as microbial infections of the surgical site, are common to all types of surgery. Fortunately, this complication is rare but when it occurs requires another operation and a course of antibiotics.
Bruising can also appear around the surgical site. This is usually prevented or reduced with a suction drain inserted at the end of the operation and removed in the days following the operation.
Knee surgery and lack of weight-bearing on the limb operated on also increase the risk of phlebitis, which can lead to a pulmonary embolism. To minimise this risk, blood thinners (in the form of daily injections or tablets) are prescribed until weight-bearing is resumed, in other words, for 6 weeks after the operation.
Failure of the osteotomy to fuse after 6 months is called nonunion and requires further surgery for the femur to heal.
In rare cases, the knee remains stiff, hot, and painful for several months after the operation. This complication, known as algodystrophy or Chronic Regional Pain Syndrome (CRPS), is unpredictable and sometimes takes a long time to heal.
Finally, rarer complications can also occur. Blood vessels (arteries, veins) can be accidentally damaged and will require vascular surgery (bypass). Nerves can also be damaged accidentally during the operation with a risk of paralysis or loss of feeling in the limb operated on, which can be transitory or permanent.
If you have any concerns about the operation, do not hesitate to talk to your surgeon or the anaesthetist and they will answer any questions you may have.
