Features of acquired valgus deformity of the lower extremities in adults

In most patients, deformity of the femur is associated with changes in the structure of its neck. Only 10% of patients have deformity of the femoral head. This group mainly includes patients after a femoral neck fracture due to improper fusion of bone tissue.

Primary changes begin with shortening of the neck and thickening of its section in the area of ​​the diaphyseal joint with the acetabulum of the pelvic bone. The cervical axis and central diaphysis are subject to minor deformation, which is further aggravated by the contraction of certain femoral muscles. With varus deformity, shortening occurs along the inner surface. With hallux valgus, the curvature occurs with damage to the external muscles.

In approximately 70% of cases, the prerequisites for such a disease of the musculoskeletal system are formed at the stage of intrauterine development of the baby. And only in 25% of patients, deformity of the femur is associated with dystrophic lesions of cartilage and bone tissue. Typically, the first signs in this case appear in old age, during menopause, against the background of the development of osteoporosis. The traumatic nature of hip curvature is present in only 5% of patients with clinically diagnosed cases. This is due to the fact that recently surgical methods for restoring tissue integrity have been actively used for hip fractures. This allows for complete recovery without the formation of various types of degenerative deformities.

In this material you can learn more about the potential causes of femoral deformity in children and adults. It also describes what methods of manual therapy can effectively and safely carry out treatment in order to completely restore the physiological state of the femur.

Why does femoral neck deformity occur?

Primary hip deformity occurs only as a congenital pathology, which may not appear until adulthood. Gradual deformation of the femoral neck is a consequence of the influence of negative factors, such as:

1. maintaining a sedentary lifestyle;
2. excess body weight;
3. smoking and drinking alcoholic beverages;
4. incorrect placement of feet when walking and running;
5. heavy physical labor with maximum load on the hip joints;
6. femoral neck fractures;
7. wearing high-heeled shoes.

Secondary deformity of the femoral neck always develops against the background of other diseases of the lower extremities. Among the most likely pathologies are:

• deforming osteoarthritis of the hip joints (cosarthrosis);
• deforming osteoarthritis of the knee joints (gonarthrosis);
• curvature of the spine in the lumbosacral region;
• symphysitis and divergence of the pubic bones during pregnancy in women;
• incorrect placement of the foot in the form of flat feet or club feet;
• tendonitis, tendovaginitis, bursitis, cicatricial deformities of the soft tissues of the lower limb.

It is also worth considering risk factors. These include intrauterine pathologies of skeletal development, rickets in early childhood, osteoporosis in middle and old age, vitamin D and calcium deficiency, endocrine diseases (hyperthyroidism, diabetes mellitus, adrenal hyperfunction, etc.).

To successfully treat hip deformity, it is necessary to eliminate all possible causes and negative risk factors. Only in this case is it possible to get a positive effect.

Varus deformity of the femoral neck (thigh)

The pathology is divided into two types: valgus and varus deformation of the femur; in the first case, the curvature occurs in an X-shaped manner, in the second - in an O-shaped manner. Both types are associated with changes in the angle located between the head and diaphysis of the femur. Normally, its parameter ranges from 125 to 140 degrees. Increasing this value to 145 - 160 degrees leads to the development of an O-shaped curvature. A decrease in the angle entails varus deformation of the femoral neck, in which the rotation of the lower limb will be sharply limited.

With hip varus, moving the leg away from the body is difficult and causes severe pain in the hip joint. Therefore, the primary diagnosis is often made incorrectly. The doctor suspects destruction and deformation of the femoral head and acetabulum. To confirm the diagnosis of deforming osteoarthritis, an X-ray of the hip joint in several projections is prescribed. And during this laboratory examination, varus deformity of the femoral neck is revealed, which is clearly visible on radiographic photographs in direct and lateral projections.

Several stages can be identified in the development of hip curvature:

1. slight deformation with a change in the angle of inclination by 2-5 degrees does not cause discomfort and does not give visible clinical signs;
2. the average degree is characterized by significant curvature and leads to the patient having problems performing certain movements in the hip joint;
3. severe deformity leads to shortening of the limb, complete blocking of rotational and rotational movements in the projection of the hip joint.

In adults, varus deformity often results from aseptic necrosis of the femoral head. This pathology also accompanies mucopolysaccharidosis, rickets, bone tuberculosis, chondroplasia and some other serious diseases.

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How does a child develop? Smooth legs (X- and O-shaped) - when? What should parents know about flat feet, club feet, bowed legs and shoes? (great article for everyone!)

Author: Lynn T. Staheli "Practice of Pediatric Orthopedics"

Terminology

Version - a normal version of limb rotation. The rotation of the tibia is the angle between the axis of the knee joint and the transmaleolar axis (the axis drawn through the ankles of the tibia). Normally, the shin is turned outward. The rotation of the femur is the angular value between the axis drawn through the femoral neck and the transcondylar axis (axis drawn through the femoral condyles). Normally there is anteversion of the femoral neck. Torsion is described as being greater than two standard deviations from the mean and is considered abnormal and is described as a deformity. Torsion deformity can be simple, involving one level, or complex, involving many segments. Complex deformations can be additive (several deformations reinforcing each other) or compensating (reducing each other). For example, internal calf torsion and internal thigh torsion are additive. On the contrary, the external torsion of the lower leg and the internal torsion of the thigh are compensatory.

Normal development

The lower limb rotates medially during the seventh week of gestation, rotating the big toe toward the midline of the body. As the fetus develops, femoral anteversion decreases from 30° at birth to 10° during maturation. The magnitude of anteversion is higher in females and in some families. With growth, the tibia rotates outward from 5° at birth to 15° by the period of maturation. Because both the femur and tibia rotate externally as the limb grows, internal tibial torsion and femoral antetorsion improve over time in children. In contrast, lateral (outer) torsion of the lower leg usually worsens over time.

Fig. 1 The lower limb rotates outward with age. Both the femur and the lower leg (tibia) rotate outwardly with age.

Survey

Although the diagnosis of torsion deformity can be made simply by external examination, the history of the development of the deformity helps to rule out other problems and understand the extent of the disorder.

HISTORY OF DEVELOPMENT

Ask about the onset, severity, impairment, and previous treatment of the problem. Find out how the patient developed. A delay in the onset of walking may raise suspicion for a neuromuscular disorder. Do you have any similar rotational disorders in your family? Often rotational deformities are hereditary and the current condition of the parents can predict the future of the child.

Fig. 2 Internal torsion of the hip, which is present in both mother and child. Examination of parents often reveals deformities similar to those present in their child.

ROTARY PROFILE

The rotation profile provides the information needed to determine the level and severity of any torsion problem. Note the degrees for both sides.

Examine in 4 stages: Examine how the child walks and runs.

Estimate the foot progression angle (FPA) when walking. FPA is the angle between the axis of the foot and the direction of movement. This value is usually determined while the child is walking along the clinic corridor. Determine the average amount of inward or outward deviation of the fingers. Negative values ​​are assigned to inward deviation of the toes. Inward rotation of the fingers (Intoeing) from -5° to -10° mild, -10°-15° moderate, more than -15° severe. Ask your child to run. A child with hip antetorsion “rakes” with his legs (“eggbeater” running pattern), deviating his feet outward during the swing phase.

Fig.3 Angle of foot deflection when walking. Determined by observing the child's gait. Normal values ​​are shown in green.

Determine hip rotation (femoral version)

by measuring rotational movements in the hip joint. Measure external and internal rotation with the child in the prone position with the knees bent to a right angle and the pelvis level. Detect movements from both sides simultaneously. Internal rotation is normally less than 60°-70°. If rotation is asymmetrical, order x-rays.

Fig.4 Rotation in the hip joints (HJ). Rotation in the hip joint is determined by the child's position on his stomach. Internal and external rotation are measured. Normal range of motion is shown in green.

Calculate tibial rotation

by measuring the hip-foot angle (TFA). TFA is defined in a prone child as the angle between the intermalleolar axis and the femoral axis. In this way, tibia rotation is measured. The difference between TMA and TFA shows rearfoot rotation. The range of normal values ​​is wide, and the average values ​​increase with increasing age. Foot placement is very important for these measurements. Allow the foot to settle into its natural position, do not position the foot yourself as this will cause measurement errors.

Fig.5 Study of the rotational status of the lower leg and foot. The rotational status of the leg and foot is best determined by examining the child in the prone position, allowing the foot to move into its natural position. In this position, it is easy to determine the hip-foot angle and the shape of the foot. Normal values ​​are shown in green.

Examine the foot

for adduction of the anterior section. The outer edge of the foot is normally straight. Curvature of the outer contour of the foot and adduction of the forefoot are usually symptoms of adducted foot (metatarsus adductus). An everted (outwardly turned) foot or a flat foot is usually the cause of outward turning of the toes. Include this data in your rotation profile. Based on the screening study and compilation of the rotational profile, establish the level and degree of torsion deformation.

Fig. 6 Diagram for determining the reasons for turning the toes inward or outward. Using a screening study and a rotational profile, it facilitates diagnosis.

SPECIAL METHODS OF INVESTIGATION

Perform additional examinations if hip rotation is asymmetrical or if rotation problems are so severe that surgical correction is considered. Before surgical treatment, take photographs to determine the degree of antetorsion in order to exclude hip dysplasia and measure the antetorsion of the hip (this means, apparently, antetorsion of the femoral neck - translator's note). Measurements are carried out according to CT or radiography in 2 projections. Typically, antetorsion exceeds 50 degrees in patients requiring surgical treatment.

Fig. 7 Asymmetrical range of rotational movements in the hip joints (HJ) requires further examination. This 12-year-old girl complained of inward turning of her toes. The rotational profile was abnormal, showing asymmetry of rotational movements in the hip joint. X-ray of the pelvis showed severe bilateral hip dysplasia (arrows). Surgical treatment of hip dysplasia was performed.

Principles of treatment

The first step is to make a correct diagnosis. When treating rotational limb problems, the most difficult part is finding good communication with the patient's family. Because the lower extremities rotate outward (laterally) over time, inward rotation of the toes spontaneously corrects in most children. Attempts to control the child's gait, sitting, or sleeping position are impossible. Such attempts only create tension in the relationship and conflict between the child and parents. Slanted insoles or inserts are ineffective.

Fig.8 Ineffectiveness of oblique insoles. Slanting insoles of various shapes were placed in the shoes (shown in black). Shown are the average values ​​of inward rotation of the toes in children who wore insoles and in the control group who did not wear insoles. Reproduced with permission from Knittle and Staheli (1976).

By analogy, daytime braces with twister cables only limit the child’s ability to walk and run. Night splints that laterally rotate the feet are better tolerated and do not interfere with the child's play, although they probably have little long-term benefit. Thus, follow-up is best. Parents need to be convinced that observational treatment is sufficient. Observation of the child includes a thorough study, collection of information, repeated checks of the correctness of the diagnosis and examinations over time. Parents should be informed that cases where the deformity does not go away are quite rare. Less than 1% of torsion deformities of the hip and tibia do not resolve on their own and may require surgical correction in late childhood. There is rarely a need for derotational osteotomy, which is quite effective.

Fig. 9 Lack of effectiveness of braces with twisting elastic inserts (twister cables). The chart compares the effectiveness of “treated” results compared to those of untreated children with antetorsion. Treatment attempts have no effect on pre- and post-treatment femoral neck anteversion measurements. From Fabry et al. (1973).

INFANT (BEFORE WALKING - INFANT)

Turning the toes outward

may be a consequence of planovalgus foot or, more often, due to external rotation contracture of the hip joints or a combination of both factors. Inward rotation of the toes occurs due to adducted big toe, adducted forefoot, or internal torsion of the shin.

External rotation contracture of the hip joint

Due to the fact that the hips are rotated (expanded) outwards while the fetus is in the uterus, lateral rotation of the hips is normal. When a child is in an upright position, his feet may turn outward. This may worry parents. Often only one foot is turned outward, usually the right one. Of the two feet, the one that is turned outward is usually normal. The opposite leg, which parents consider normal, often has forefoot adduction or internal tibia torsion.

Fig. 10 Physiological infantile outward rotation of fingers. Outward rotation of the fingers in early infancy occurs due to external rotation contracture of the hip joints. In this infant, internal rotation is limited to 30° (top photo), while external rotation is limited to 80° (bottom photo). It is the result of external rotation of the limbs, which resolves spontaneously over time.

Adducted first toe

usually described as both a spastic contracture of the abductor hallucis muscle and a “searching toe”. It is a dynamic deformity due to relatively excessive tension in the abductor hallucis muscle that occurs during the stance phase. This deformity may be associated with adduction of the metatarsals. This condition goes away on its own during the maturation of the nervous system, when a more precise balance of the foot muscles is established. Does not require treatment.

Fig. 11 “Searching finger” (“serchin toe”). Dynamic deformation due to excess stress adductor hallucis

Forefoot adduction

– a spectrum of various deformities, characterized by medial deviation of the forefoot of varying degrees. The prognosis is closely related to foot rigidity.

Fig. 12 Severity of forefoot adduction. Draw a line that divides the heel in half. Normally it crosses the 2nd finger. This line passes through the 3rd finger for mild, between the 3rd and 4th for moderate, and between the 4th and 5th fingers for severe deformity. From a study by Bleck (1983)

Metatarsal adduction (Metatarsus adductus)

It is a flexible deformity and occurs due to the constrained position of the fetus in the uterus. Like other deformities, it resolves spontaneously over time. Most deformities are corrected during the first year of life, the rest in the subsequent period of childhood. Requires regular monitoring and repeated checks of the condition of the foot. No braces, casting, special shoes or exercises are required.

Varus adduction of the foot (Metatarsus varus)

Rigid forefoot adduction with a tendency toward no improvement. This rigid foot shape is uncommon compared to the normal adducted foot (metatarsus adductus). Varus adduction of the foot is characterized by rigidity with the presence of a fold on the plantar part of the foot. Foot development is often accompanied by incomplete spontaneous correction. The deformity does not cause functional impairment and is not the cause of corns. This pathology creates a cosmetic defect and, if severe, difficulties in choosing shoes. Don't forget about the deformity known as skewfoot. “Sickle foot” occurs in children with weakened ligaments of the joints and is characterized by pronounced adduction of the forefoot in combination with valgus of the hindfoot. Most parents want the deformity to be corrected. The deformity is corrected by staged casting of the leg to the groin area, starting at approximately 6 months. Plaster casts are applied at intervals of 1-2 weeks until the foot is corrected. In children over 2 years of age, correction with plaster casting is sometimes effective, but is more difficult for the child and parents to accept. Surgical treatment is very rarely necessary, since varus adduction of the foot (metatarsus varus) does not cause functional impairment or secondary deformities.

AGE AFTER STARTING WALKING (TODDLER)

Internal rotation of the toes is more common in the second year of life and is usually detected when the infant begins to walk. This deformity occurs due to internal torsion of the lower leg, adducted foot (metatarsus adductus) or adducted big toe.

Internal torsion of the leg (ITT).

VTG is the most common cause of inward rotation of the fingers. Often it is two-sided. If the VTG is unilateral, then it is more often on the left. Dynamic observation is the best treatment option. Fillauer or Denis Browne night splints are widely prescribed, but they do not matter in the long-term prognosis of treatment. Recovery occurs both with and without treatment.

Fig. 13 Bilateral internal torsion of the lower leg. Hip-foot angle is negative (red line) for both legs

Fig. 14 Unilateral internal torsion of the lower leg. Internal torsion of the lower leg is often asymmetrical and is usually worse on the left side

Avoid daytime braces and special shoes because they slow your child's movements and can damage their self-esteem. Correction occurs spontaneously, but often takes 1-2 years. Warn parents that the time required for correction is calculated in years and not weeks or months.

AGE AFTER 2 YEARS. (CHILD)

Inward rotation of the toes in childhood after the start of walking (after 2 years) most often occurs due to antetorsion of the thigh (femoral neck) and rarely due to persistent internal torsion of the lower leg. In late childhood, outward rotation of the toes may be due to external torsion of the thigh or external torsion of the lower leg. The natural development of the femur is an outward rotation of the femur as the child grows, which often leads to correction of the internal torsion of the tibia and worsening of the external torsion of the tibia.

Internal torsion of the leg (ITT)

less typical than external torsion for older children. In a child over 8 years of age, VTG may require surgical correction if it does not resolve on its own and produces significant functional impairment and cosmetic deformation. Surgical treatment may be indicated when the hip-foot angle is internally rotated by more than 10°.

Fig. 15 Persistent torsion of the lower leg. Rotational deformities do not always go away with time. This girl still has torsion of the lower leg (see arrow), which causes functional impairment and requires surgical correction (derotational osteotomy of the lower leg bones).

External torsion of the tibia (ETT)

Because the tibia rotates laterally (outward) with age, internal tibial torsion (ITT) improves, and external tibial torsion (ETT) worsens. IGT can cause pain in the knee joint. This pain occurs at the patellofemoral joint and is thought to be caused by an imbalance in the relationship between the knee axis and the line of progression. This violation of the ratio is most clearly manifested when the external torsion of the lower leg is combined with the internal torsion of the thigh. The knee joint is rotated inwards, and the ankle joint outwards, both joints are out of alignment with the line of motion, which causes “malalignment syndrome”. This condition leads to gait disturbance and pain in the patellofemoral joint.

Femoral antetorsion

Antetorsion of the femur (more precisely, the neck of the femur) or internal torsion of the femur is usually first detected in the age group of 3 to 5 years and is most common in girls. Often, residual effects of hip antetorsion are observed in the patient’s parents. A child with femoral neck antetorsion sits in the “W” position, stands with his knees turned inward (“kissing patella”) and runs awkwardly with an “egg-beater” gait. Internal rotation in the hip joint exceeds 70°. Internal hip torsion is considered mild if internal rotation in the hip joint is about 70°-80°, moderate at 80°-90°, severe at 90° or more. External rotation in the hip joint decreases accordingly, because the full range of rotational movements in the hip joint is 90-100°. Femoral antetorsion is usually most pronounced between 4 and 6 years of age and then normalizes. Recovery occurs due to a decrease in the angle of anteversion of the femoral neck and lateral rotation of the tibia. In an adult, hip antetorsion does not cause degenerative arthritis (arthrosis) and rarely causes functional impairment. Femoral neck antetorsion cannot be treated conservatively. The persistence of severe antetorsion over the age of 8 years may be an indication for derotational osteotomy of the femur.

Fig. 16 Internal (medial) torsion of the femur. This girl has internal hip torsion. Her patellas are rotated medially in a standing position. External rotation in the hip joint is 0° (top photo). External rotation in the hip joint is 90° (bottom photo).

Retrotorsion of the hip

may be more of a problem than is generally recognized. Retrotorsion is most common in patients with epiphysiolysis of the femoral head. Presumably the “shearing” force acting on the growth zone increases. Retrotorsion is associated with an increased risk of developing degenerative arthritis (arthrosis) and a gait with the toes turned outward. Gait problems are usually not severe enough to require surgical treatment.

Valgus deformity of the necks of the femurs (hips)

Juvenile and congenital valgus deformity of the femur is often diagnosed, which is characterized by a rapidly progressive course. When looking at a patient with such a deviation, it seems that he is bringing his legs together at the knees and is afraid to unclench them. X-shaped valgus deformity of the femoral necks can be a consequence of hip dysplasia. In this case, the first signs of hip curvature appear at approximately the age of 3-5 years. Subsequently, the angle of deviation will only increase due to the ongoing pathogenic processes in the cavity of the hip joint. Shortening of the ligaments and contraction of muscle fibers will increase the curvature and deformity.

Congenital deformity of the femoral neck in a child may be caused by the following teratogenic factors:

• pressure on the growing uterus from the internal organs of the abdominal cavity or when wearing tight, constricting clothing;
• insufficient blood supply to the uterus and growing fetus;
• severe anemia in a pregnant woman;
• disruption of the ossification process in the fetus;
• breech presentation;
• previous viral and bacterial infections in the late stages of pregnancy;
• taking antibiotics, antivirals and some other drugs without medical supervision.

Congenital valgus deformity of the femur is characterized by severe flattening of the articular surface of the acetabulum and total shortening of the diaphyseal portion of the femur. An X-ray examination shows an anterior and upward displacement of the femoral head with curvature of the neck and shortening of the bone section. Fragmentation of the epiphysis may appear at a later age.

The first clinical symptoms of valgus deformity of the femoral neck in children appear when they begin to walk independently. The baby may have shortened one leg, lameness, and a peculiar gait.

The juvenile type of pathology is that valgus deformity of the hip begins to actively develop in adolescence. At the age of 13–15 years, hormonal changes in the body occur. With an excessive amount of produced sex hormones, the pathological mechanism of epiphysiolysis (destruction of the head of the femur and its neck) can be triggered. When bone tissue softens under the influence of the growing body weight of a teenager, valgus deformation begins with deviation of the distal end of the femur.

Children with obesity and overweight who lead a sedentary, sedentary lifestyle and are addicted to carbohydrate foods are at risk. It is necessary for such adolescents to be periodically shown to an orthopedist for timely detection of the disease at an early stage of its development.

Consequences and complications

In the absence of proper treatment, the epiphysis of the femur continues to shift, which causes a deterioration of trophic processes in the affected area. The most common complication of varus deformity of the femur is coxarthrosis deformans. Improper load distribution causes secondary deformations of the lower extremities, in particular, the knee joint and ankle, and the development of degenerative processes in the tissues of the joints up to their complete destruction. If treatment is not timely, the symptoms of the disease tend to increase, and the pathology leads to a significant limitation of the patient’s mobility and deep disability.

Timely detection and comprehensive treatment of congenital and acquired varus deformity of the femur allows one to maintain full mobility of the limb and prevent the development of complications.

Symptoms, signs and diagnosis

Clinical symptoms of valgus and varus deformity of the femur are difficult to miss. A characteristic deviation of the upper leg, lameness, and specific positioning of the legs are objective signs. There are also subjective sensations that can signal such trouble:

• nagging, dull pain in the hip joints that occurs after any physical activity;
• lameness, dragging of the leg and other gait changes;
• feeling that one leg has become shorter than the other;
• dystrophy of the thigh muscles on the affected side;
• the rapid appearance of a feeling of fatigue in the leg muscles when walking.

Diagnosis always begins with an examination by an orthopedic doctor. An experienced doctor will be able to make the correct preliminary diagnosis during the examination. Then, to confirm or exclude the diagnosis, an x-ray of the hip joint is prescribed. If characteristic signs are present, the diagnosis is confirmed.

Diagnosis of the disease

An orthopedic doctor or surgeon can assume the presence of varus deformity based on a combination of characteristic symptoms, but an accurate diagnosis can only be made on the basis of an X-ray examination. Characteristic signs that allow diagnosing VD include:

• reduction of the neck-shaft angle;
• increase in the interacetabular-epiphyseal angle;
• expansion of the growth zone;
• flattening or hypoplasia of the acetabulum.

How to treat hip bone deformity?

Valgus deformity of the femur in a child is perfectly amenable to conservative methods of correction. But only in the early stages can the physiological state of the head and neck of the femur be completely restored. Therefore, when the first signs of trouble appear, you should seek medical help.

The following manual therapy methods can be used to treat deformity of the femoral head:

1. kinesiotherapy and therapeutic exercises are aimed at strengthening the muscles of the lower extremities and, by increasing their tone, correct the position of the head of the bone in the acetabulum;
2. massage and osteopathy allow, through physical external influence, to carry out the necessary correction;
3. reflexology starts the recovery process by using the body’s hidden reserves;
4. physiotherapy, laser treatment, electrical myostimulation are additional methods of therapy.

Any correction course is developed individually. Before treating a femur deformity, you should consult an experienced orthopedist.

In our manual therapy clinic, each patient has the opportunity to receive professional advice from an experienced orthopedist completely free of charge. To do this, just make an appointment for the first time.

Treatment methods

In the early stages of varus deformity in childhood, conservative treatment is possible, which includes:

• stretching a limb with a load;
• wearing special orthopedic shoes to prevent secondary disorders of the skeletal system of the lower extremities;
• physiotherapeutic procedures;
• drug therapy to improve metabolic processes and strengthen general immunity.

Since treatment of childhood VD takes a long time, it is recommended to send the child to special sanatoriums where complex therapy is provided.

Treatment of varus deformity in adults that arises as a result of systemic diseases should begin with correction of the leading pathology.

Surgical treatment

With an increase in the interacetabular-epiphyseal angle over 60 degrees, severe gait disturbances, and shortening of the limb, conservative treatment does not seem to be effective. In these cases, as well as with rapid progression of deformities, surgical intervention is indicated to:

• correct curvatures and reduce displacement of the femoral neck;
• equalize the length of the legs;
• reconstruct the trochanter of the femur.

During the subtrochanteric osteotomy operation, the distal part of the femur is abducted in relation to the trochanter and the proximal part is brought in by installing a plate on the diaphysis of the femur, as well as repositioning the triangular bone formation. After the operation, an immobilization plaster cast is applied to the limb for a period of 2 to 4 months.

To correct the length of the limbs, an operation is performed to lengthen the bone of the short leg using an auto- or allograft; in rare cases, the contralateral limb is shortened to restore symmetry.