Introduction
In medical terminology, bow legs are called genu valgum. This refers to an abnormal leg axis. The knees are too close together, while the feet are too far apart due to foot malpositions.
In addition to the foot malpositions, vitamin deficiencies and especially calcium deficiency are often responsible for the knock-knees. Untreated knock-knees can lead to consequential damage to the hip and knee joints. Due to the malfunction, the cartilage surfaces wear down more quickly, which can result in considerable discomfort in the joints. For this reason, corrective surgery by orthopedic surgeons is usually recommended at a young age for axial deviations of more than 20 degrees in order to prevent subsequent damage.
Surgery for knock-knees
Surgery is particularly indicated if the malposition of the legs is already very pronounced in childhood and as a result severe impairment of everyday life and sports is possible. The leg axis correction of the knock-knees aims to straighten the legs and thus prevent possible subsequent complications such as increasing wear and tear and early arthrosis. Symptoms may initially be absent and only appear at a very late stage.
A complete replacement of the knee joint is only carried out at a very advanced stage. Nevertheless, patients should be made aware prior to surgery that post-operative treatment requires a great deal of patience and that the subsequent strain must also be significantly reduced at first. The operation is often performed under general anesthesia.
In some cases a local anesthesia may be sufficient. In addition, a bloodless state is induced during the operation. For this purpose, a cuff, which can be inflated, is placed high up on the thigh, which stops the blood supply for a certain time.
This makes the operation easier for the doctors, as they have a better view of the operating area. In the case of knock-knees, the correction is made on the thigh bone near the knee joint. As the outer joint surfaces of bow legs are too heavily loaded, the surgeon tries to straighten this overload and to steer it more in the direction of bow legs.
This procedure is also known as varus osteotomy among medical professionals. There are two ways to correct the leg axis. Either a wedge is removed from the affected bone or incorporated to achieve the desired degree of angle.
In most cases, the decision is made to remove a bone wedge. In order to gain access to the femur, an incision must be made on the outside of the femur. The size of the incision is about 5-8 cm.
An arthroscopy is performed first. This is a reflection of the knee joint. The joint surfaces are examined in particular.
Since the outer joint surfaces are more heavily loaded in bow legs, it is possible that the cartilage there is already very frayed. During arthroscopy, special equipment can be used to remove excess and frayed cartilage and the first signs of wear and tear. This is followed by the so-called “unfolding” of the thigh bone.
For this purpose, a wedge-shaped piece of bone is removed in such a way that the tip of the wedge faces the inside of the thigh. This creates a gap in the bone, which can now be filled with the patient’s own bone material, which is taken from the iliac crest. In this case, this is called a closed-wedge osteotomy.
If, on the other hand, the gap remains open, this is called an open-wedge osteotomy. In the latter case, the gap is gradually filled up with newly formed bone material. This method is particularly suitable for younger patients in whom bone growth has not yet stopped.
In both options, the leg is finally fixed in an exactly straight position using plates and screws. The individual steps of the operation are checked by X-rays and documented exactly. Like most operations, the repositioning osteotomy for knock-knees also involves some risks.
Typical complications that can occur include post-operative bleeding, bruising and infection. Furthermore, nerves can be injured on the thigh, which can result in paralysis or sensory disturbances. Similar damage can occur as a result of blood congestion.
Furthermore, the success of the operation is not guaranteed. The bone healing may not be able to meet the desired requirements. It is also possible that inflammation may occur due to the plates and screws that have been attached, or that the patient may react with an allergic reaction to the material used.
In a preliminary consultation, the patient or the parents of a child should be informed about possible risks.Follow-up treatment in hospital takes about 4-5 days. Afterwards, if no complications occur, the patient can be discharged. In the first 2-3 weeks, the patient should take good care of the operated leg and should not weigh more than 20 kg.
Therefore, he will be given crutches for walking. The material used today for bone fixation is a very angular stable plate system. Therefore, depending on the healing process, full weight bearing may be possible after 3 weeks.
In order to be able to put weight on the knee joint and the leg early, the patient receives targeted physiotherapy at an early stage. This also accelerates the healing process. Following the healing process, lightly straining sports such as cycling or swimming can be performed.
How well a correction of the malposition heals depends on many factors. The age and extent of the bow legs play an important role. In general, people with a corrected malalignment have an increased risk of developing osteoarthritis. Nevertheless, studies have shown that most patients are free of complaints for more than 10 years after surgery and do not need a knee joint prosthesis.
