Hip




(1)
Groningen, The Netherlands

 




Hip Movement Limitations in Babies and Infants



Hip Movement Limitation Away from the Midline of the Body






  • A312070_1_En_9_Figa_HTML.gif Complaint: the mother has the feeling that there is something wrong with the hips of her 3-month-old child. Changing diapers is difficult and one or both leg(s) do not abduct easily. The child has no pain.


  • A312070_1_En_9_Figb_HTML.gif Assessment: there is an abduction limitation of the hip(s) and an extra buttock fold (Fig. 9.1).

    A312070_1_En_9_Fig1_HTML.jpg


    Fig. 9.1
    (a) Three-month-old girl with an abduction limitation in a right hip dislocation. (b) Extra buttock fold on the right side. The extra buttock fold is the most proximally located (arrow). (c) Galeazzi test. At the age of 3 months the difference in leg length is not so pronounced and is easily missed


  • A312070_1_En_9_Figc_HTML.gif Differential diagnosis:



    • developmental dysplasia of the hip ( congenital dysplasia of the hip)



      • dislocatable hip (neonatal hip instability)


      • acetabular dysplasia


      • subluxation/dislocation of the hip


  • A312070_1_En_9_Figd_HTML.gif Explanatory note: developmental dysplasia of the hip. Developmental dysplasia of the hip refers to the complete spectrum of pathological conditions involving the developing hip, ranging from dislocatable hip to acetabular dysplasia, subluxation and dislocation. The clinical presentation varies with age.


Dislocatable hip

The number of dislocatable hips in newborns is 10–20 per 1000 births. A dislocatable hip can be easily dislocated and reduced in the first days of life. It is caused multifactorially by laxity limited to the hip joint capsule, and is influenced by hormonal and genetic factors. This laxity has a natural tendency to restore itself. A dislocatable hip corrects itself in 60 % of cases within 1 week and in 90 % of cases within 2 months after birth.


Acetabular dysplasia

In some cases, without a subluxation/dislocation, the acetabular roofing of the femoral head will be insufficient (Fig. 9.2). This situation is known as acetabular dysplasia. It affects 10–20 out of 1000 3-month-olds. In contrast to a dislocatable hip and a dislocation, with acetabular dysplasia physical assessment tends to show no anomalies. Acetabular dysplasias are mostly diagnosed because children with increased risk of developmental dysplasia of the hip undergo supplementary assessments (Table 9.1).

A312070_1_En_9_Fig2_HTML.gif


Fig. 9.2
(a) Normal hip joint. (b) Acetabular dysplasia: there is insufficient coverage of the femoral head by the acetabulum. (c) Subluxation: the femoral head has lost contact with the acetabulum. The acetabular labrum, a ring-shaped connective tissue attached to the acetabular rim, also known as limbus, has been stretched superiorly and posteriorly by the migration of the femoral head and is pressed flat against the ilium by the femoral head. (d) Dislocation: a neoacetabulum (new acetabulum) has been formed around the iliac bone. The acetabular labrum is obstructing the joint



Table 9.1
Risk factors for developmental dysplasia of the hip













Positive family history

Full breech presentation

Incomplete breech presentation

Torticollis


Subluxation/dislocation of the hip

A permanent subluxation/dislocation develops in 10 % of dislocatable hips, thus affecting 1–2 in 1000 children. By the time the child is 2–3 months old, secondary changes develop. An arbitrary distinction can be made between a subluxation and a dislocation. The transition from a subluxation to a dislocation is gradual. The femoral head will have respectively no full contact or no contact at all with the acetabulum.

In a hip dislocation the femoral head is dislocated backwards and upwards (Fig. 9.3). The superior and posterior side of the acetabulum is flattened due to pressure from the femoral head, and on the upper side of the normal or true acetabulum a new cavity is formed in the iliac bone, the new acetabulum or neoacetabulum (Fig. 9.2). The angle between the femoral head or neck and the femoral shaft is increased (enhanced valgus position) (Fig. 9.4). The femoral head has an enhanced anteversion (Fig. 9.5). In a complete dislocation the inverted hypertrophied acetabular labrum, also called limbus, obstructs the joint (labrum is Latin for lip and limbus for edge). In a subluxation this is not the case, but the superior and posterior part of the acetabular labrum is pressed flat by the femoral head against the iliac bone. The cavity is smaller, and the transverse acetabular ligament, which crosses the acetabular notch, is shortened. The ligament of the head of the femur, also known as teres ligament (teres is Latin for round and long), which runs from the acetabular fossa to the femoral head, is thicker and longer than normal, and the fat in the acetabular fossa has hypertrophied (Fig. 9.6). Between the femoral head and the acetabulum lies the tendon of the shortened iliopsoas muscle (Fig. 9.7), that constricts the joint capsule which acquires an hourglass shape. There is also a shortening (contracture) of the hip adductors, especially the adductor longus. Without anesthesia the hip joint cannot be reduced manually.

A312070_1_En_9_Fig3_HTML.jpg


Fig. 9.3
Anatomical preparation of a frontal cross-section of the right hip in a premature with a hip dislocation. The green arrow identifies the true acetabulum. In a hip dislocation the femoral head is dislocated posteriorly and superiorly, forming a neoacetabulum (new acetabulum) (red arrow) (Image received in 1985 from Prof. A. Campos da Paz Jr., M.D. Ph.D., Brasil.) (Figs. 9.3, 9.6 and 9.7 are published in: Campos da Paz A, Jr., Kalil RK. Congenital dislocation of the hip in the newborn. A correlation of clinical, roentgenographic and anatomical findings. Ital J Orthop Traumatol. 1976;2:261–72)


A312070_1_En_9_Fig4_HTML.gif


Fig. 9.4
The neck-shaft angle, is on average 134° at birth, increasing in the first years of life to an average of 144° and diminishing gradually to an average of 126° in adulthood. In a congenital hip dislocation there is an enhanced valgus position of the proximal part of the femur (Redrawn from: Lanz T von. Über umwegige Entwicklungen am menslichen Hüftgelenk. Schweiz. Med Wschr. 1951;81:1053–65)


A312070_1_En_9_Fig5_HTML.gif


Fig. 9.5
(a) Transverse crossection of the hip joint in a premature with a normal hip joint (anatomical preparation). The anteversion of the acetabulum is on average 7° shortly after birth, and 16.5° in adulthood. In a newborn the anteversion of the proximal part of the femur is on average 31°, in an adult 11°. (b) CT-scan of an 18-month-old boy with a right side (R) congenital hip dislocation. The distance between the right femoral head and the acetabulum (d) is larger than that of the left side (L). The edge of the posterior side of the right acetabulum is flattened. Acetabular anteversion (a) is 20° on both sides and femoral anteversion (b) 60° on both sides. In a dislocation an enhanced femoral anteversion is usually 50–60°


A312070_1_En_9_Fig6_HTML.gif


Fig. 9.6
(a) Anatomical preparation of right-side dislocation. The acetabular labrum is obstructing the joint. The ligament of the femoral head is thicker and longer than normal. The joint capsule is constricted in an hourglass shape because the shortened iliopsoas tendon is located between the femoral head and the hip socket. (b) The most important structures are outlined (Images received in 1985 from Prof. A. Campos da Paz Jr., M.D. Ph.D., Brasil)


A312070_1_En_9_Fig7_HTML.jpg


Fig. 9.7
The shortened iliopsoas tendon (arrow) is located between the right femoral head and the acetabulum (Image received in 1985 from Prof. A. Campos da Paz Jr., M.D. Ph.D., Brasil)


Incidence of Developmental Dysplasia of the Hip


Among Caucasians, subluxations/dislocations occur in 1–2 in 1000 children. Among Laplanders and Navajo Indians this is 20 per 1000 births. At a rate of 1 in 10,000, Africans and Asians have a relatively low incidence of developmental dysplasia of the hip. In African Bantu babies developmental dysplasia of the hip has almost never been seen (Fig. 9.8).

A312070_1_En_9_Fig8_HTML.jpg


Fig. 9.8
(a) In some cultures children are wrapped up; Navajo Indians carry their children on their backs using a cradle board (Tikonagan). In this way the hips are brought into adduction and extension, increasing the risk of developmental dysplasia of the hip. (b) African mothers carry their child on their back, which bends and abducts the hips. This is the best position to counteract developmental dysplasia of the hip

The left hip is affected twice as often as the right hip. This anomaly occurs in girls four more times than in boys. If developmental dysplasia of the hip occurs with no parent involved, a child has a 6 % risk of having it; with at least one parent involved the risk is 12 % and with one parent and a sibling 36 %. In a complete breech presentation the chances of a dislocation are 2 % and in an incomplete breech presentation 20 % (Fig. 9.9). According to the literature, in children with torticollis the chances of developmental dysplasia of the hip vary from 2 to 29 %.

A312070_1_En_9_Fig9_HTML.jpg


Fig. 9.9
Hip dislocations are frequent with breech presentations especially in an incomplete breech presentation when there are hyperextended knees


Syndromal and Neurogenic Hip Dislocation


Developmental dysplasia of the hip is distinguished from syndromal and neurogenic hip dislocation. In some syndromes (Table 9.2) and neurological anomalies, such as spina bifida, there is an increased chance of dislocations. These types of hip dislocation will not be discussed further.


Table 9.2
Syndromes with a highly increased risk of hip dislocation



















Arthrogryposis

Diastrophic dwarfism

Down syndrome

Ehlers-Danlos syndrome

Larsen syndrome

Hunter syndrome

Hurler syndrome


See Appendix for characteristics of syndromes


Natural History


What happens if a child with a subluxation/dislocation or an acetabular dysplasia is not treated?

If a child with a subluxation/dislocation is not treated, an unsightly limp will develop and the child will have to forgo many sports and recreational activities. In addition, in a onesided subluxation/dislocation there is a difference in leg length that can amount to about 6 cm in a complete dislocation (Fig. 9.10). A complete dislocation does not cause any pain. A subluxation forms a new acetabulum in the iliac bone. A neoacetabulum will be painful in adulthood.

A312070_1_En_9_Fig10_HTML.jpg


Fig. 9.10
Leg length difference of 2 cm in the left thigh as a result of a developmental dysplasia with a dislocated left hip. The leg length difference can increase in adulthood up to 5 or 6 cm

When there is acetabular dysplasia, chances of early arthrosis at ages 40–50 are about 70 %. Prematurely, between the ages of 20 and 30 many develop pain after prolonged walking, especially when strolling (Fig. 9.11).

A312070_1_En_9_Fig11_HTML.gif


Fig. 9.11
(a) Normal hip. Good distribution of the load on the hip joint. (b) Acetabular dysplasia. Abnormally large load on a part of the hip joint with chances of degenerative changes. (c) In older children and adults, in an anteroposterior X-ray of the hip the relation between the acetabulum and the femoral head is displayed by means of the CE angle of Wiberg. C stands for “center” and E for “lateral Edge of the acetabular roof”. The CE angle is formed by a line drawn from the middle point of the head parallel to the median line, and a line drawn from the middle point of the head to the lateral edge of the acetabulum. The CE angle is 25° or more when the acetabulum properly covers the femoral head. A CE angle of 20° or less means that there is acetabular dysplasia. An angle between 20° and 25° is a gray area and not clearly dysplastic. In this case the CE angle is 10° and the acetabulum is clearly dysplastic


Physical Assessment


The anomalies found on physical assessment for a subluxation/dislocation vary with age (Table 9.3).


Table 9.3
Examination findings for developmental dysplasia of the hip by age

























Age

Physical examination

0–2 months

Positive Ortolani and/or Barlow test(s)

2–9 months

Abduction limitation

Around 1 year

Difference in leg length

After the child starts walking

Waddling gait

Acetabular dysplasia

Physical assessment tends to show no anomalies


Physical Assessment in a Newborn



Ortolani test

In the Ortolani test the dislocated hip is reduced manually (Fig. 9.12). This test can only be carried out if the child is relaxed. A child that is resisting tightens the hip adductors, which makes it more likely for the test to fail. The child must be placed with the back on the mother’s lap. If possible, let the mother bottle-feed the child.

A312070_1_En_9_Fig12_HTML.gif


Fig. 9.12
Ortolani test. “Jerk of entry”. (a) The hip joint is dislocated. The hips are bent at 90°. (b) By abducting the leg the hip is repositioned over the posterior edge of the hip socket. (c) By increasing abduction the examiner feels that something shifts with a “jerk”

The hips are bent 90°. Now the hips are examined individually. If the examiner begins with the right hip, his left hand will encompass the child’s right upper leg. The thumb will lie against the inner side and the index and middle fingers against the outer side. The right hand of the examiner fixes the left upper leg and the pelvis. By abducting the right leg (starting from the midline), the dislocated femoral head is pushed back over the posterior edge of the acetabulum into the socket. The examiner will have the feeling that something has shifted with a “jerk”. About the same thing is experienced if one rubs the knuckles of the fists over each other. This is incorrectly described as a “click”. The “jerk” indicates that the femoral head has been reduced over the posterior edge of the acetabulum. Ortolani describes this phenomenon as a “segno dello scatto” (sign of a ridge), in this way trying to indicate that the phenomenon should be felt much rather than heard. Audible clicking coming from tendons, muscles, bone or cartilage is common and doesn’t mean anything.


Barlow test

This test consists of two manoeuvres (Fig. 9.13). In the first manoeuvre the hip is dislocated and in the second it is reduced. It is a test to find out whether a non-dislocated hip can be dislocated. The hips are flexed 90° and the knees are maximally flexed. The examiner encompasses the leg to be examined in the same way as is done in the Ortolani test, but in the first part of the test one presses with the thumb on the inner side of the upper part of the thigh. If there is laxity of the joint capsule the femoral head can be easily displaced over the posterior edge of the acetabulum. In the process one can feel the “jerk” when dislocation of the hip is possible. In the second manoeuvre the middle finger is pressing on the outer side of the greater trochanter, so that feeling the “jerk” means that the femoral head has been reduced over the posterior edge of the acetabulum.

A312070_1_En_9_Fig13_HTML.gif


Fig. 9.13
Barlow test. This test is used to ascertain whether a non-dislocated hip joint can be dislocated. (a) The hips are bent 90° and the knees are maximally flexed. (b) If there is ligamental laxity, the hip can be dislocated with pressure of the thumb on the inner side of the proximal part of the thigh. At that moment the examiner feels that something changes place with a“jerk”. (c) In the second part of the manoeuvre the hip is reduced by pressing on the greater trochanter with the index and middle fingers. The moment that the hip is reduced the examiner feels once more that something changes position with a “jerk”

Why is a positive Ortolani test found in some cases, and in other cases a positive Barlow test? This depends on whether a dislocatable hip in a newborn is dislocated or not. This is probably influenced by the position of the legs during the assessment. If a child with a dislocatable hip lies supine with the hips in flexion and in 80–90° abduction — a normal resting position — then the hip can be reduced. In that case there is a positive Barlow test. A joint can be dislocated when the child lies with extended and adducted legs, that means that there is a positive Ortolani test.

One should start by slowly extending the legs and adducting them if only the Ortolani test is to be done. The hip will dislocate. Next, perform the test as described above. It is recommended to start with the Ortolani test, and if it turns out negative then do the Barlow test.

Doing a hip assessment on a newborn is not a simple matter. Ample experience is required. Occasionally there is a dislocation in newborns, irreducible when doing the Ortolani test, as secondary intrauterine changes will have already taken place in terms of contractures of the iliopsoas muscles and the adductors. This anomaly is called teratogenic hip dislocation.


Physical Assessment at the Age of 3–4 Months


As a rule, the Ortolani and Barlow tests for a dislocatable hip are positive in the first days to a few months after birth. Three situations are possible after that:



  • Ligamental laxity of the hip joint capsule does not correct itself after a few months. The Ortolani and Barlow tests remain positive for a longer period of time. This is very rare.


  • Ligamental laxity of the hip joint capsule corrects itself within several months, the femoral head sits in the joint cavity, and the hip develops normally. In some cases, despite the fact that the femoral head is in the acetabulum, the development of the hip joint will not be entirely optimal. The acetabular coverage of the femoral head is not ideal, and there is acetabular dysplasia. A child with acetabular dysplasia does not necessarily show physical anomalies.


  • The hip remains dislocated causing in the first 2 or 3 months after birth contractures of the iliopsoas muscle and the adductors, especially the adductor longus muscle. Due to the contractures the hip cannot be reduced with the Ortolani test. At first the adduction contracture is not that obvious and can easily be missed. Sometimes it is first noticed by the mother or carers, because changing diapers becomes more difficult and the legs cannot be sufficiently abducted (Fig. 9.1). Normally, at the age of 3 months legs can still be abducted 80–90° when the hips are flexed 90°. Abduction of less than 60° should be considered as abnormal and further radiological assessment is indicated. A312070_1_En_9_Fige_HTML.gif

    An extra buttock fold is noticeable in children who are 2–3 months old and have a dislocated hip joint. The extra fold is caused by the dislocation, because the thigh at the level of the dislocated hip becomes relatively too short and a surplus of soft tissue occurs which causes the extra fold. This extra buttock fold is close to the perineum, and not somewhere else on the posterior side of the thigh A312070_1_En_9_Fige_HTML.gif (Fig. 9.1). Such folds are present in 20 % of children without hip disorders, hence an extra buttock fold without an abduction limitation has no relevance.

    The normal groin and buttock folds on the dislocated side are longer and deeper than on the non-dislocated side. In unilateral dislocations there is also a difference in length of the thighs. This can be demonstrated with the Galeazzi test (Fig. 9.1). Here the knees and hips are flexed to a degree such that the soles of the feet are approximated on the examination table. If there is a difference in knee lengths, to the disadvantage of the dislocated side, one speaks of a positive Galeazzi test. The difference in length between the thighs can also be observed by flexing the hips and knees to 90° (Fig. 9.14). This is actually a better method, because the Galeazzi test is also positive when there is a difference in length below the knees. At the age of 2–3 months the difference in leg length is not that pronounced though, so it can easily be missed. A312070_1_En_9_Fige_HTML.gif In bilateral dislocations there is of course no difference in leg length, and the abduction is symmetrically limited. A312070_1_En_9_Fige_HTML.gif

    A312070_1_En_9_Fig14_HTML.jpg


    Fig. 9.14
    (a) The difference in length between the thighs can also be observed by flexing the hips and knees 90°. (b) This is in principle a better method than the Galeazzi test (Figs. 9.1a and 9.15c), because the Galeazzi test is also positive if there is a difference in leg length below the knees. This examination only measures the difference in the thighs


Physical Assessment Around the First Year of Life


As the child becomes older, the abduction in the non-dislocated hip diminishes while the adduction contracture of the dislocated hip decreases. In other words, the difference in abduction becomes less pronounced and more difficult to see. At the same time, the extra buttock fold disappears and the normal groin and buttock folds on the dislocated side become as long and as deep as those on the non-dislocated side. The soft parts adapt themselves. By contrast, the difference in leg length increases (Fig. 9.15).

A312070_1_En_9_Fig15_HTML.gif


Fig. 9.15
(a) 16-month-old girl with a left-sided hip dislocation. At this age the difference in abduction is less pronounced. (b) The same patient as in Fig. 9.15a. The extra buttock fold is absent or gone. (c) The same girl as in Fig. 9.15a. With age, the difference in leg length in a one-sided hip dislocation becomes more noticeable. The Galeazzi test shows a clear difference in knee height to the disadvantage of the dislocated left side


Physical Assessment After the Child Can Stand and Walk


Occasionally we see that a congenital hip dislocation is identified at an older age. This usually involves a dislocation of both hip joints. In such cases there is a symmetrical abduction limitation that is not as easily noticeable as an unilateral abduction limitation, as is the case in unilateral dislocations. In addition, there is no difference in leg length between the thighs because both hip joints are dislocated, so in most cases there is a similar shortening of both thighs. When these children stand up, the air space between the legs, around the perineum, is widened (also called thigh gap). There is an abnormal hollow back (hyperlordosis) and the pelvis is tilted forwards (Fig. 9.16). Parents often complain that the child has a waddling gait. The Trendelenburg test is positive (Fig. 9.17). The Trendelenburg test serves to assess the strength of the hip abductors. One can ask the patient to lift the left leg. When there is normal strength in the right hip abductors, the left side of the pelvis is lifted. In such cases the Trendelenburg test is negative. In a hip dislocation the distance between the origin and insertion of the hip abductors is shortened. This makes the hip abductors relatively too long and therefore less effective when the child stands on the leg with the hip dislocation, when lifting the other (contralateral) leg the pelvis on the contralateral side will drop downwards. In this case the Trendelenburg test is positive (Fig. 9.17).

A312070_1_En_9_Fig16_HTML.gif


Fig. 9.16
(a) Girl aged age 2 years and 3 months. There is a bilateral hip dislocation with a widened air space just below the perineum (thigh gap). (b) There is enhanced lumbar lordosis with a forward-tilting pelvis


A312070_1_En_9_Fig17_HTML.jpg


Fig. 9.17
Trendelenburg test. (a) A patient with a leftsided hip dislocation stands with both legs on the ground. (b) The patient is asked to lift the left leg. If there is normal strength in the hip abductors of the right hip the left side of the pelvis is lifted. The Trendelenburg test is negative. (c) When lifting the right leg the pelvis drops on the right side. The Trendelenburg test is positive. There is weakness in the hip abductors of the left hip




  • A312070_1_En_9_Figf_HTML.gif Supplementary assessment: When should an ultrasound assessment of the hips take place or anteroposterior X-rays of the pelvis be taken? This is done if the physician, upon physical examination, finds indications of a possible developmental dysplasia of the hip. Additional radiological assessment is recommended if physical examination shows no irregularities but there is developmental dysplasia of the hip in the family or there has been a breech birth presentation, or there is a torticollis (Table 9.1).

    Ultrasound or echographic assessment makes use of sound waves. This type of assessment is useful until about the age of 1 year. In older children it is unreliable. The advantage of ultrasound is that no radiation is involved. A disadvantage of ultrasound is that the professional doing the examination must have ample experience with ultrasound assessment of children’s hips in order to establish the proper diagnosis. If this person lacks sufficient experience with such assessments, there is a risk that the hip irregularity will not be recognized or that hip anomalies will be seen that aren’t there (Fig. 9.18). The advantage of an X-ray is that it easier to assess than an ultrasound (Fig. 9.19). The disadvantage is of course that radiation is involved.

    A312070_1_En_9_Fig18_HTML.jpg


    Fig. 9.18
    (a) Ultrasound of the right hip in a 3-month-old child. The bone core of the femoral head is not present yet. (b, c) The α angle between the basic line (iliac bone) and the acetabular roof line shows the degree of bony development of the acetabulum, and in a normally developed hip it exceeds 60°. The β angle that is formed by the basic line and the inclination line gives an impression of the cartilaginous development of the acetabulum. In a normal hip this angle is smaller than 55°. Graf came up with several classifications based on the ultrasound. The simplest classification is: class I, normal hip with an α angle larger than 60° and β angle smaller than 55°; class II, dysplasia with an α angle between 43° and 60° and a β angle between 55° and 77°; class III: subluxation with an α angle smaller than 43° and a β angle larger than 77°; class IV: dislocation, α and β angles cannot be measured


    A312070_1_En_9_Fig19_HTML.gif


    Fig. 9.19
    (a) Graphic depiction of an anteroposterior X-ray of the pelvis. To assess a hip dislocation and acetabular dysplasia a number of lines are drawn. A horizontal line is drawn from the y-shaped cartilage of both femoral heads: the Hilgenreiner or y-line. The y-shaped cartilage is the common growth plate of the iliac, ischial and pubic bones. The Perkins lines are dropped, from the lateral edge of the acetabula which lie perpendicular to the Hilgenreiner line. In normal hips and in acetabular dysplasia the medial edge of the proximal femoral metaphysis lies within the Perkins line, in a dislocation it lies outside. The degree of acetabular dysplasia is the acetabular angle, often abbreviated as AC angle and also called acetabular index. The acetabular angle is formed by the Hilgenreiner line and a line through the acetabular roof (acetabular roof line). In the figure the right hip displays a normal acetabular angle and the left hip a congenital hip dislocation with an enlarged acetabular angle. In a hip dislocation there is always an underdevelopment of the acetabulum, and the ossification of the epiphysis is smaller than on the normal contralateral side. The normally flowing line of Shenton, set by the arch of the lower edge of the superior ramus of the pubic bone and the medial edge of the medial border of the metaphysis, is interrupted in a dislocation (and in an enhanced anteversion-valgus position of the proximal part of the femur). (b) Anteroposterior image of the pelvis in a 6-month-old child. The lines of Hilgenreiner and the lines of Perkins are drawn. The right side displays a normal hip, the left side a congenital hip dislocation. A hip dislocation is always accompanied by an underdevelopment of the acetabulum, (acetabular dysplasia)

    A positive Ortolani or Barlow test in a newborn can be easily visualized with ultrasound technology because it is a dynamic assessment. If after the age of 1–2 months the Ortolani and Barlow tests are negative but physical examination points to other possible hip anomalies (for example abduction limitation), then ultrasound assessment of the hips is advisable. The same applies if physical examination shows no abnormalities despite an increased risk of developmental dysplasia (Table 9.1). Anteroposterior X-rays of the pelvis are made right away if the ultrasound shows abnormalities.

    The degree of acetabular dysplasia is determined on the basis of the acetabular angle (Fig. 9.19) and the Tönnis and Brunken table (Table 9.4).


    Table 9.4
    Threshold values of the acetabular angle in degrees, for the diagnosis of mild or severe acetabular dysplasia, by age and gender according to Tönnis and Brunken (1968), based on a study of 2294 acetabular angles


















































































































































    Age

    Acetabular dysplasia girls

    Acetabular dysplasia boys

    Mild

    Severe

    Mild

    Severe

    Right

    Left

    Right

    Left

    Right

    Left

    Right

    Left

    Months

    1 + 2

    35.8

    36.1

    41.6

    41.6

    (27.7)

    31.2

    (31.8)

    35.2

    3 + 4

    31.4

    33.2

    36.3

    38.7

    27.9

    29.1

    32.4

    33.7

    5 + 6

    27.3

    29.3

    31.8

    34.1

    24.2

    26.8

    29.0

    31.6

    7–9

    25.3

    26.9

    29.4

    31.1

    (24.6)

    25.4

    28.9

    29.5

    10–12

    24.7

    27.1

    28.6

    (31.4)

    23.2

    25.2

    27.0

    29.1

    13–15

    24.6

    26.9

    (29.0)

    (31.7)

    23.1

    24.0

    (27.5)

    27.7

    16–18

    (25.0)

    (26.1)

    (29.3)

    30.4

    (23.8)

    (25.8)

    (28.1)

    (30.0)

    19–24

    24.1

    26.4

    28.4

    (30.8)

    20.6

    23.2

    24.4

    27.3

    Years

    2–3

    21.8

    23.3

    25.6

    27.1

    21.0

    22.7

    25.3

    26.9

    3–5

    (17.9)

    21.2

    21.3

    25.8

    19.2

    19.8

    23.5

    23.8

    5–7

    19.3

    19.8

    23.4

    23.8

    16.8

    19.3

    20.9

    23.2


    Mild acetabular dysplasia: Threshold values equal to the average plus one time the standard deviations

    Severe acetabular dysplasia: Threshold values equal to the average plus twice the standard deviation

    Hips with an acetabular angle between the average and once-to-twice the standard deviation (mild acetabular dysplasia) develop normally in 40 % of cases, present an elevated normal value in 40 % of cases, and in 20 % of cases have acetabular dysplasia. Hips with an acetabular angle of the average plus two times the standard deviation or more (severe acetabular dysplasia) do not develop normally (persistent acetabular dysplasia) if no treatment is deployed. The numbers in parentheses are higher than in the current curve trajectory one would expect. A number should be taken that lies between the number above and the number below


  • A312070_1_En_9_Figg_HTML.gif Primary care treatment: In primary care all children, in any event at the age of 3 months, should be examined for developmental dysplasia of the hip. Radiological assessment should be requested if physical examination shows signs that point to developmental dysplasia of the hip as well as in children with increased chances of this condition (Table 9.1).


  • A312070_1_En_9_Figh_HTML.gif When to refer: If physical and/or radiological assessment point to signs of developmental dysplasia of the hip1.


  • A312070_1_En_9_Figi_HTML.gif Secondary care treatment: dislocatable hip. Hip abduction treatment for 8 weeks using a Pavlik harness (Fig. 9.20).

    A312070_1_En_9_Fig20_HTML.gif


    Fig. 9.20
    Pavlik harness. A disadvantage of the Pavlik harness is that parents sometimes have difficulty fitting it


Acetabular dysplasia

We will treat it, if the anteroposterior X-ray of the pelvis shows acetabular dysplasia. However, this can sometimes be overtreated.

Up to the age of 3 months treatment is carried out using a Pavlik harness. For babies 3–6 months old one can choose a Pavlik harness and a Visser hip abduction orthosis (Fig. 9.21). Small babies get a Pavlik harness at this age, and larger children a Visser hip abduction orthosis. The Pavlik harness is too small for older children. Children with acetabular dysplasia are treated using a dynamic hip abduction orthosis (Visser hip abduction orthosis) between the ages of 6 and 12 months.

A312070_1_En_9_Fig21_HTML.jpg


Fig. 9.21
(a, b) Visser hip abduction orthosis. (b) The Visser hip abduction orthosis has hinges, which allows mobility in the hip joints within certain limits (greater than 90° flexion and 30° abduction)

Children between the ages of 1 and 2 years get a Hilgenreiner orthosis (Fig. 9.22), generally for 6 months. This orthosis allows the child to walk. For the conditions that have to be met by a hip abduction orthesis to treat developmental dysplasia of the hip, see Table 9.5. Abduction treatment in children older than 2 years produces no better results than the natural recovery. A natural recovery is waited for until about the age of 4 years. After this age, a few degrees of improvement in the acetabular angle may be expected. If at 4 years of age the acetabular angle is not expected to normalize a pelvic osteomy must be carried out in order to improve coverage of the femoral head (Table 9.6, Figs. 9.23, 9.24, 9.25, 9.26, 9.27, and 9.28).

A312070_1_En_9_Fig22_HTML.jpg


Fig. 9.22
Hilgenreiner orthosis. One can walk with this orthosis in contrast to a Pavlik harness and a Visser hip abduction orthosis. A Pavlik harness and a Visser hip abduction orthosis are stock items, a Hilgenreiner orthosis has to be made to size



Table 9.5
Conditions that a hip abduction orthosis for treatment of developmental dysplasia of the hip must meet















The hips are held in flexion to neutralize the contracture of the iliopsoas muscle.

The hips are held in 90° flexion and 30°–60° abduction for optimal centralization of the femoral head in the hip socket.

Forced extreme abduction should be avoided to prevent ischemic femoral head necrosis.

The hips should be movable within certain limits for an optimal nutritional condition of the cartilage.

The orthosis should be user-friendly. The materials of the orthosis should not cause hypersensitivity.



Table 9.6
Treatment followed by the authors for a dislocatable hip, acetabular dysplasia with or without a preceding treatment for dislocation, persistent subluxation and a discongruent joint
































































Anomaly

Age

Treatment

Dislocatable hip

0–2 months

Pavlik harness

Dysplasia

0–6 months

Pavlik harness

Dysplasia

3–12 months

Visser hip abduction orthosis

Dysplasia

1–2 years

Hilgenreiner orthosis

Dysplasia

2–6 years

Pemberton pelvic osteotomy

Mild dysplasia

6 years – fully grown up

Salter pelvic osteotomy

Severe dysplasia

6 years – fully grown up

Wait until the child is fully grown

Mild to severe dysplasia

>10 years

Triple osteotomy
 
Fully grown up

Ganz pelvic osteotomy

Severe dysplasia

Fully grown up

Ganz pelvic osteotomy

Persistent subluxation

>10 years

Chiari pelvic osteotomy

Dysplasia with discongruent joint

Mostly > 10 years

Shelf arthroplasty or Chiari pelvic osteotomy

(Nonspherical femoral head and/or acetabulum)
   


A312070_1_En_9_Fig23_HTML.gif


Fig. 9.23
Pelvic and femoral osteotomies for treatment of acetabular dysplasia (Redrawn from: Staheli RT. Fundamentals of pediatric orthopaedics. 4th ed. Philadelphia/Baltimore/New York/London/Buenos Aires/Hongkong/Sydney/Tokyo: Lippincot Williams & Wilkins. 2008. p. 217)


A312070_1_En_9_Fig24_HTML.gif


Fig. 9.24
Left side. (ac) Schematic representation of a Pemberton pelvic osteotomy. The piece of bone obtained from the left iliac crest is wedged in-between the osteotomy surfaces. (d) Acetabular dysplasia with an enhanced anteversion/valgus position of the proximal part of the left femur. (e) Result after a Pemberton pelvic osteotomy and a proximal femoral varus external rotation osteotomy


A312070_1_En_9_Fig25_HTML.gif


Fig. 9.25
(ac) Schematic representation of a Salter pelvic osteotomy. The piece of bone obtained from the iliac crest is grafted into the openwedge osteotomy and fixed using two Kirschner wires. (d) Acetabular dysplasia. (e) Situation immediately and (f) 3 monthes after a Salter pelvic osteotomy


A312070_1_En_9_Fig26_HTML.jpg


Fig. 9.26
(a) Left-sided acetabular dysplasia in an adult. (b) Situation after a Ganz pelvic osteotomy


A312070_1_En_9_Fig27_HTML.jpg


Fig. 9.27
(a) In a congenital hip dislocation it is not always possible to obtain an optimal result. There is a subluxation of the left hip. (b) Situation after a Chiari pelvic osteotomy


A312070_1_En_9_Fig28_HTML.gif


Fig. 9.28
(a) Acetabular dysplasia of the left hip with an enlarged femoral head. (b) Situation after a shelf arthroplasty. Fixed with a screw

In the indication for hip osteotomy several principles should be taken into consideration. The largest deformity is corrected first. This is usually the acetabulum. If the deformity is located in the acetabulum as well as in the proximal femoral part, the pelvic osteotomy is combined with a proximal femoral osteotomy. In a Pemberton pelvic osteotomy the shape of the acetabulum is deformed because the center of rotation of this osteotomy is located at the level of the y-cartilage. A Pemberton pelvic osteotomy can be performed only up to the age of 6. Above this age the acetabulum has insufficient time to remodel itself.

A Salter pelvic osteotomy can be performed at any age but is only suitable for mild acetabular dysplasia.

Sutherland and triple osteotomies are usually performed on children older than 10, and a Ganz pelvic osteotomy once a child has reached adulthood.

Pemberton, Salter, Sutherland, triple and Ganz pelvic osteotomies can only be performed on a congruent joint. For severe dysplasias that still have a congruent joint there is no adequate solution for children aged 6–10. In most cases one waits until the child is past age 10 to do a triple pelvic osteotomy, or a Ganz pelvic osteotomy can be performed in adulthood.

A Chiari osteotomy for lateralization or subluxation of the hip, a shelf arthroplasty or a Chiari pelvic osteotomy for acetabular dysplasia with a discongruent joint are generally performed on children older than 10.


Pemberton pelvic osteotomy

This osteotomy can be performed for mild and severe acetabular dysplasia until the maximum age of 6. It is an osteotomy of the ilium. The osteotomy begins just above the lateral edge of the acetabulum and runs through up to the y-cartilage. The y-cartilage is the center of rotation in this osteotomy.


Salter pelvic osteotomy

The Salter pelvic osteotomy is suitable for mild acetabular dysplasia and can be performed at any age. The procedure improves the acetabular angle by a maximum of 10–15° and the CE angle by no more than 10°. The symphysis is the center of rotation of this ilium osteotomy.


Sutherland pelvic osteotomy

Double osteotomy through the ilium and the pubic bone. This procedure is rarely performed because of the limited correction that can be achieved here.


Triple osteotomy

Osteotomy through the ilium, superior and inferior ramus of pubis.


Ganz pelvic osteotomy

The Ganz osteotomy is a technically difficult operation. The osteotomy is done around the acetabulum, avoiding the y-cartilage. For this reason, the operation can only be done if the y-cartilage is closed. A greater correction can be achieved with the Ganz osteotomy than with a triple osteotomy.


Chiari osteotomy

This osteotomy is performed if there is a lateralization of the femoral head or a discongruent joint (nonspherical head or socket). This is an osteotomy of the iliac bone, after which the femoral head is pressed inward with the distal part of the pelvis. It is a bony coverage without cartilage. The procedure is performed if the previously listed osteotomies aren’t possible.


Shelf arthroplasty

A shelf arthroplasty is performed when there is a discongruent joint. Bone from the iliac crest is grafted onto the iliac bone above the femoral head. In this procedure there is no joint cartilage between the femoral head and the newly covered area either.


Femoral osteotomy

A proximal femoral varus external rotation osteotomy can be performed when there is a severe enhanced valgus-anteversion position of the proximal femoral part. In this case a wedge of bone is removed from the proximal part of the femur on the medial side after which the distal part of the thigh is adducted and externally rotated and fixed with osteosynthetic material (in this case a hook plate).


Subluxation/dislocation of the hip up to the age of 6 months

In 80–90 % of cases, repositioning in children up to the age of 6 months can be achieved by using a hip abduction orthosis (Visser hip abduction orthosis) or a Pavlik harness. After 2 weeks with the orthosis or harness, the success of the reduction can be assessed on an anteroposterior X-ray of the pelvis or an ultrasound of the hip (Fig. 9.29). For the anteroposterior X-ray of the pelvis a X-ray permeable orthosis is used. If reduction is achieved, the abduction treatment with orthosis or harness is continued until the acetabular angle on an anteroposterior X-ray of the pelvis is normalized (as a rule 6 months). If it isn’t possible to get the hip reduced (Fig. 9.30), noninvasive reduction under anesthesia is indicated, followed by spica cast immobilization with the hips in 90–100° flexion and 45–60° abduction (Fig. 9.31) for a 3-month period, followed by abduction orthosis treatment until anteroposterior X-ray of the pelvis show a normalized acetabular angle. This treatment is continued until the age of 2 years as needed. In some cases a tenotomy of the adductor longus and psoas muscles is necessary to achieve reduction. Open reduction is rarely necessary at this age (Flowchart 9.1).
Jun 26, 2017 | Posted by in PEDIATRICS | Comments Off on Hip
Premium Wordpress Themes by UFO Themes