Case Presentation Tibia vara Reported by SC 楊惠蘚 Supervisor VS 林啟禎/R藍聖閔/R王恆基

Basic Information Chief Complaint Name:黃○豪 Sex: Male Age: 12y/o Chart No: 09496995 Past history: DM(-), hypertension(-), asthma(-), NKDA Left lower leg turns inward, varus change and pain on the medial side of left knee for one year The patient is a 12 year old boy without any underlying disease His C C is~~~ 2

Clinical course 10~11 years old: 1) Varus change of left lower leg. 2)pain on left knee, especially on the medial side During this year: 1) Varus change and pain progressed. 2) left lower leg weakness Went to 奇美 H last April and some unknown drugs were prescribed, but in vain. This is his clinical course When he was~~~1)was noted and2) was also coomplained During~~ Due to symptums progressed, he went to 奇美 H and some unknown drugs were prescribed, but in vain. Therefore he went to our OPD this march . X-ray showed varus deformity of left knee joint and metaphysealdiaphyseal angle was 18 degree varus, and thus Blount disease was impressed. Considering the patient's situation, operation was suggested.Therefore he was adimitted to 07A16A for further operation. Went to our OPD for help. X-ray showed varus deformity of left knee joint and metaphysealdiaphyseal angle was 18 degree varus, and thus Tibia vara was impressed. 3

Varus deformity of Lt knee joint On scanography we can see Varus deformity of Lt knee joint and length discrepancy is shorter over left 2 centimeter And we can measure metaphyseal diaphyseal angle. The angle is formed by two lines. One is perpendicular line to the longitudinal axis of tibia and the other is through two beaks of metaphysis (to determine transverse axis of tibia metaphysis) This angle is an early indicator of tibia vara The patient’s metaphyseal-diaphyseal angle is about 18 de Varus deformity of Lt knee joint Metaphyseal-diaphyseal angle ≒18 degrees Length discrepancy, shorter over left 2.0 cm 4

~~~The surgery will be discussed later~~~ Physical examination Weight / Height: 92kg / 156 cm Extremities: freely movable, Varus left lower leg, painful on the medial side of left knee when lower leg flexed. left lower leg muscle power decreased mildly, compared with right lower leg But he has morbid obesity. His height is 160 cm, but his weight is up to 90 kg His extremities is freely movable, varus left lowerleg was noted. He felt painful on the medial side of left knee when lower leg flexed. His left lower leg muscle power decreased mildly, compared with right lower leg Based on his history and image. tibia vara was impressed Due to his symptoms progressed, the surgery was suggested and we will discuss about it later ~~~The surgery will be discussed later~~~ 5

Discussion ~~Tibia Vara~~ Let’s move on our discussion about tibia vara 6

Tibia Vara (Blount Disease) An acquired disease of the proximal tibial metaphysis (medial side) growth disorder about ossification of the medial aspect of the proximal tibial physis, epiphysis, and metaphysis Varus and internal torsion of tibia, genu recurvatum Cause unknown  Infection? Trauma? Osteonecrosis? A latent form of rickets… Hereditary + developmental factor Tibia vara also called blount disease It is considered an acquired~~ To be specific, It is a growth disorder about ossification of the medial aspect of the proximal tibial physis, epiphysis, and metaphysis. Because of the medial proximal tibial dysplasia, it will make varus angulation and internal rotation of the knee. This deformity is an irreversible pathologic changes The exact cause is unknown Suggested factors include Infection Trauma Osteonecrosis or A latent form of rickets… A combination of hereditary and developmental factors is most likely cause Most importantly, weight bearing must be necessary The pathophysiological factor is abnormal stress placed on the medial proximal tibial physis that leads to growth suppression early walking and obesity are strongly associated abnormal stress placed on the posteromedial proximal tibial epiphysis that leads to growth suppression start to walk early, usually when aged 9-10 months Based on his mother’s description, he started to walk independently at age of 11~12 months, Weight bearing must be necessary, since the disease does not occur in nonambulatory patients I have more detailed introduction about clinical findings later The term osteochondrosis deformans tibiae is not accurate because it describes a disorder in which the primary or secondary centers of ossification undergo avascular necrosis.6 Avascular necrosis has never been found in either form of Blount disease. Early walking, Obesity 7

Two Types of Tibia Vara Infantile type (more common) Before 8 years of age D/D with Physiological bowlegs (esp. <2 y/o) 60%: bilateral, symmetrical symptoms: tibia vara↑vs. physiological bowing ↓ There are two types of tibia vara. One is infantile type and the other is adolescent type Infantile type is more common than adolescent type it is Often onset before 8 years of age We must make differential diagnosis with Physiological bowlegs , esp. less than 2 years old children This is very important, but also difficult initially Because the symptoms are similar. They both often show bilateral and symmetrical deformity. but tibia vara is an irreversible pathological change, so the deformity should get worse gradually On the other hand, physiological bowleg will resolve as growth Physiologic genu varum is a common torsional deformity that occurs secondary to normal in utero positioning excessive physiologic bowing often is found in individuals with the infantile form of the disease. It is known that epiphyseal compression inhibits physeal growth (the Heuter-Volkmann law) and distraction stimulates growth Preceding slide 8

9 The picture is radiograghic changes in infantile type We can see progression of medial epiphyseal and metaphyseal deformity through six stages as growth At fourth stage the medial portion of metaphysis is right downward angle In this x ray we can see short, thin ,slopes down epiphysis and metaphysis. The medial physis is more irregular than lateral side And proximal metaphysis forms projection medially that can be palpable. 9

Two Types of Tibia Vara Adolescent type( 8 y/o ~ 13 y/o) Adolescent form Partial closure of physis After trauma or infection Late-onset tibia vara Obese children Without a distinct cause Our patient: Obesity Age: 12 years old No obvious trauma or infection history The other type of tibia vara is adolescent type it is onset between 8 and 13 years old And this type is also divided into two type One is Adolescent form caused by partial closure of physis after trauma or infection The other type is called late onset tibia vara that occurs on obese children, esp black children without a distinct cause Let ‘s back to our patient He has morbid obesity, 12 years old and he has no obvious trauma or infection history So he is grouped under late-onset tibia vara The pathophysiological change in late-onset tibia vara is similar with infantile type, but it often shows unilateral deformity because symmetrical compressive shear forces across the proximal tibial physis promote disruption and cause compression and deviation of normal intercondylar ossification Before bone maturity Weight bearing must be necessary, since the disease does not occur in nonambulatory patients Blount disease most likely is caused by a combination of excessive compressive forces on the proximal medial metaphysis of the tibia and altered endochondral bone formation. It is unclear whether the deformity is caused by an intrinsic alteration of bone formation that is exacerbated by compressive forces or by compressive forces that cause a disruption in normal endochondral bone formation Asymmetrical compressive shear forces across the proximal tibial physis promote disruption and cause compression and deviation of normal intercondylar ossification 10

How to Diagnose Clinic manifestations internal tibial torsion genu recurvatum a prominent metaphyseal beak (medial, infantile) leg-length discrepancy (adolescent>infantile) Knee pain, esp. medial aspect (adolescent) Bilateral infantile VS. Unilateral adolescent Female>male, black children Obesity!!! Clinical manifestations and radiography play important roles to diagnose tibia vara internal tibial torsion and genu recurvatum are most common And sometimes we can find a palpable prominent metaphyseal beak on the medial side and leg-length discrepancy like our patient Knee pain esp. on the medial side is a common complaint in adolescent type, but less in infantile type Bilateral varus change is often seen in infantile type. On the other hand adolescent type has unilateral change Female is more than male Obesity is strongly related. Preceding slide The clinical presentation of the different types of tibia vara varies according to the age of onset. In infantile tibia vara, children generally start to walk early, usually when aged 9-10 months.13 At the onset of the disease, differentiating between early infantile Blount disease and marked physiologic bowlegs is difficult. Physiologic genu varum is a common torsional deformity that occurs secondary to normal in utero positioning. The tight posterior hip capsule causes an external rotation of the thigh at the hip. When combined with internal tibial torsion, the resulting appearance is a varus deformity. This physiologic deformity usually resolves spontaneously by the time the child is aged 2 years. In contrast to physiologic genu varum, infantile Blount disease can progress to severe deformity. The infantile form is generally more prevalent in females, blacks, and those with marked obesity. It is associated with a prominent metaphyseal beak, internal tibial torsion, and leg-length discrepancy; involvement is bilateral in approximately 80% of cases.18 The metaphyseal prominence, or beak, may be palpable over the medial aspect of the proximal tibial condyle. Patients usually do not complain of pain. However, the deformity of the lower extremity can be quite pronounced.5, 6, 10 In contrast, patients with adolescent tibia vara usually complain of pain at the medial aspect of the knee. These patients are typically overweight or obese. In contrast to infantile tibia vara, involvement is unilateral in 80% of cases; the involved leg sometimes is shorter than the opposite leg by as much as 2-3 cm. The degree of varus deformity usually is not as severe as in individuals with the infantile form and usually does not exceed 20°. The metaphyseal prominence, or beak, may be palpable over the medial aspect of the proximal tibial condyle. Patients usually do not complain of pain. However, the deformity of the lower extremity can be quite pronounced.5, 6, 10 althou 11

How to Diagnose Radiography Tibiofemoral angle Metaphyseal-diaphyseal angle Early indicator >11 degrees close observation >20 degrees confirm Tibiofemoral angle ≒30 degrees Radiography is the primary tool used to diagnose tibia vara There are two kinds of angle that can help us make diagnosis One is Tibiofemoral angle formed by two longitudinal axis of tibia and femur One study show average Tibiofemoral angle of adolescent tibia vara is 14 degrees Our patient’s tibiofemoral angle is about 30 degree The Metaphyseal-diaphyseal angle is more useful to indicate tibia vara In studies, if the angle is more than 11 degree, we should keep close oservation Because it may indicate tibia vara angles greater than 20º could confirm true tibia vara and some studies suggest 17 degree Our patient’s Metaphyseal-diaphyseal angle ≒18 degrees and combined with his clinic finding, we can diagnose tibia vara In the study, most children with metaphyseal-diaphyseal angle of 11 degrees or more developed Blount disease, whereas children with angles of less than 11 degrees had physiological bowlegs that resolved with growth. The metaphyseal-diaphyseal angle is obtained by measuring the angle formed between a line drawn parallel to the top of the proximal tibial metaphysis and another line drawn perpendicular to the long axis of the shaft of the tibia. Overlap may be found in measurements between patients with and without tibia vara. Angle measurements are 9º ± 3.9º in cases of physiologic bowing and 19º ± 5.7º in patients with Blount disease. Reportedly, angles greater than 20º confirm true tibia vara in children, whereas angles of 15-20º may or may not indicate tibia vara. Different radiologic measurements have been used in an attempt to confirm the presence of Blount disease. The femoral-tibial angle helps confirm the varus position of the leg, but it can be misleading secondary to the rotation of the leg, which may be positional or due to a coexisting rotational abnormality 圖:Anteroposterior radiograph representing important angles for staging typical for the adolescent form. Obvious varus deformity in the proximal tibia with no sloping or bar formation is present (bars do not occur in the adolescent form). A: Tibiofemoral angle. B: Metaphyseal-diaphyseal angle. C: Metaphyseal-epiphyseal angle. Anteroposterior radiograph representing important angles for staging typical for the adolescent form. Obvious varus deformity in the proximal tibia with no sloping or bar formation is present (bars do not occur in the adolescent form). A: Tibiofemoral angle. B: Metaphyseal-diaphyseal angle. C: Metaphyseal-epiphyseal angle. Radiographs of the knee are critical in assessing and staging the severity of the deformity. An anteroposterior standing radiograph of both lower extremities and a lateral radiograph of the involved extremity are used (see the top image above). Fragmentation with a protuberant step deformity and beaking of the proximal medial tibial metaphysis are the major features of the infantile group. The lateral cortical wall of the upper tibial metaphysis is nearly straight. Differentiating between severe physiologic bowing and infantile-type Blount disease is difficult in early childhood. Thus, corrective intervention is not recommended when the patient is younger than 2 years. Early changes of infantile Blount disease can be assessed by measuring the metaphyseal-diaphyseal angle of the proximal tibia; that is, the angle formed by the intersection of a line through the transverse plane of the proximal tibial metaphysis with a line perpendicular to the long axis of the tibial diaphysis (see the lower image above). The severity of the varus deformity is based on the tibiofemoral angle as measured on standing anteroposterior radiographs that include the ankle, knee, and most of the femur; the metaphyseal-diaphyseal angle; and the metaphyseal-epiphyseal angle, that is, the angle formed by the intersection of a line through the transverse plane of the proximal tibia epiphysis with a line through the transverse plane of the metaphysis (see the lower image above). Computed tomography (CT) has no defined role in the evaluation of Blount disease MRI can aid in evaluation and treatment of patients with Blount disease is debatable. Metaphyseal-diaphyseal angle ≒18 degrees 12

Treatment Younger than 2 years : Operative treatment is not recommended  Age of 2~5-year-old: Observation or a trial of bracing Adolescent type: observation first Surgical indication: increasing severity of symptoms or progression of deformity Osteotomy: opening and closing wedge, spike, dome, and oblique Treatment depends on the age of the child and the severity of the varus deformity. The first principle is observation in all types The children at age of 2 to 5 year old can try bracing treatment But if the treatment is in vain and severity of symptoms or progression of deformity, even if disability occur. Surgery should be suggested. There are many kinds of osteotomies including opening and closing wedge, spike, dome, and oblique Our patient have varus change and internal rotation of tibia, but medial side of metaphysis doesn’t slope down very much, so we choose oblique osteotomy to correct his deformity   Observation or a trial of bracing is used most frequently for children aged 2-5 years. However, progressive deformity usually requires osteotomy.7, 10 Operative treatment is not recommended for children younger than 2 years because the deformity may be an exaggerated physiologic genu varum. Nonoperative treatment In a child older than 2 years, orthotic treatment can be used when the deformity is increasing or if the child has a tibiofemoral angle greater than 15°, a metaphyseal-diaphyseal angle of greater than 11°,23 and a metaphyseal-epiphyseal angle of 25-30°.18 Ambulatory daytime bracing using an above-the-knee brace with a free ankle may favorably alter the natural history of patients with tibia vara who are younger than 3 years and who have Langenskiöld stage I or II deformity, because the deformity is often reversible at these stages.24 Nonetheless, documentation of the effectiveness of bracing is difficult because tibia vara can resolve spontaneously.  If the deformity persists or increases to stage III or IV with daytime brace treatment, osteotomy is required. If possible, it is preferable to perform the osteotomy before the child is aged 4 years to prevent recurrence.25 If deformity is severe (ie, Langenskiöld stage V or VI), operative correction is essential. Orthotic devices are ineffective in controlling the varus deformity in adolescents, and the treatment is surgical. If the deformity does not improve with orthotic treatment and the disease progresses radiographically to advanced stage II or stage III deformity, surgical correction should be performed. Furthermore, surgery is recommended for a deformity that is increasing in severity and disabling the child, or if the child has a tibiofemoral angle greater than 15°, a metaphyseal-diaphyseal angle greater than 14°, and a metaphyseal-epiphyseal angle greater than 30°. Absolute indications for surgery are depression of the tibial plateau, impending closure of the medial physis of the upper tibia (stage IV), and ligamentous laxity of the knee.18 Osteotomy has been the most frequently used form of surgical management.6 Many different types of osteotomies have been described in the literature, including opening and closing wedge, spike, dome, and oblique osteotomies.22, 26, 27 In the more skeletally mature individual, the valgus osteotomy can be carried out through the physeal scar. However, it is important to remember that in the younger child, the osteotomy must be carried out below the insertion of the patellar ligament because the proximal tibia physis is still open.7 13

This picture show procedure of oblique osteotomy We exposure tibia and insert a pin at 45-degree angle 1 cm distal to the tibial tubercle And then do oblique osteotomy below the pin External rotation around face of cut makes valgus and external rotation of distal tibia to correct deformity Then fixation with screws 14

Fix patella upward and We can see varus left lower leg 2) thigh-foot angle is normal on right side and decrease even becomes negative on left 3) We can see bilateral mild hyperextention of knee genu recurvatum bil 15

This is fibula We did fibula osteotomy first And exposred tibia Insert a K pin at 45 degree angle 1 cm distal to the tibial tubercle perform oblique osteotomy above the k pin External rotation of distal tibia Then fixation with screws

Varus deformity and internal rotation were corrected after oblique osteotomy And metaphyseal diaphyseal angle reduces to 1 degree

After oblique osteotomy Cast : changed at 4 weeks, worn for 8 weeks or until union is evident on X ray Weight bearing: allowed as tolerated if callus is visible on X ray After care Cast 多久 Full weight-bearing post-op x ray

Differential Diagnosis Physiologic bowing Congenital bowing Rickets Ollier disease Trauma, tibial plateau fracture Osteomyelitis, chronic Metaphyseal chondrodysplasia There are some problems we should make Differential Diagnosis The most important is Physiologic bowing Because it is difficulty to differentiate between infantile tibia vara and Physiologic bowing esp. less than 2 years old children Others like Congenital bowing, Rickets, tumor such as Ollier disease , tibial plateau fracture, Osteomyelitis, Metaphyseal chondrodysplasia should be ruled out before we make diagnosis of tibia vara Enchondromatosis, or multiple enchondromas, refers to a group of disorders of which Ollier disease is the best known. This is nonhereditary disorder which usually presents in childhood. Nominally, the disease consists of multiple enchondromas. However, on radiographs, streaks of low density are seen projecting through the diaphyses into the epiphyses of the long bones, due to ectopic cartilage deposits. With age, the cartilage may calcify in the typical "snowflake" pattern.  The affected extremity is shortened (asymmetric dwarfism) and sometimes bowed due to epiphyseal fusion anomalies.  Osteomyelitis, chronic(區分的finding) 19

~~Thanks for your listening~~ 20

10-year-old black boy with morbid obesity This is 10-year-old black boy with morbid obesity We can see bilateral genu varum 10-year-old black boy with morbid obesity 21