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The conservative management of congenital dislocation of the hip
The Conservative Management of Congenital Dislocation of the Hip
R. H. Gross
As a result of early diagnosis of C D H conservative treatment has become increasingly important since the majority of children will be at an age when operative treatment is not necessary. In spite of this major achievement, a number of uncertainties and conflicting opinions still shroud a clear understanding of the problem of C D H in this age group. This paper attempts to analyse our present knowledge in a manner which will allow the orthopaedist to formulate a treatment plan on the basis of available information rather than dogmatic principles. The two essential treatment goals are: 1. Attain and maintain reduction. 2. Avoid avascular necrosis. Any strategy must take into account: 1. Age 2. Variations in intra-articular pathology 3. Presence or absence of contractures. Other more poorly understood factors such as individual variations in blood supply to the femoral head may also influence the result. This discussion will exclude the 'teratologic' hip with fixed contractures and capsular constriction, as these hips cannot be managed non-operatively.
Although it is recognised that many dislocatable hips discovered by Ortolani-Barlow manoeuver will stabilise without treatment and progress into normal hips, most authorities recommend treatment of this type of hip instability. If treatment is deferred it is imperative that careful follow-up be maintained during the 1st year of life, especially for the first 3 months. The factors determining which hips will spontaneously stabilise are not fully understood. Differences in pathological anatomy are important and some insight is provided from dissections of stillborn babies. Even when teratologic hips are excluded there is considerable variation in the descriptions of the
Treatment O f The Neonate Although treatment of CDH is simpler and more gratifying in the newborn than at any other time certain key questions do not presently have defined answers. These are: 1. What is the pathological anatomy of the dislocatable hip ? 2. Which hips must be treated? 3. If treated, how long should splinting be applied? 4~ How can complications be avoided? Richard H. Gross M D , Department of Orthopaedics, College of Medicine, University of Florida, Box J-246, J H M Health Center, Gainesville, Florida 32610, USA. Current Orthopaedics (1987)i, 267 274 © 1987LongmanGroup UK Ltd
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THE CONSERVATIVE MANAGEMENT OF CONGENITAL DISLOCATION OF THE HIP
'normal C D H ' by the various authors. Their findings using their own terminology are as follows: 1. Dunn described three grades :1 Grade 1 - - T h e dislocatable hip in which the basic pathology is instability of the limbus, allowing dislocation. Grade 2 - - T h e limbus is everted, the femoral head no longer spherical. Grade 3 - - T h e limbus is inverted to form the floor of a false acetabulum. 2. Stanisavljevic defined two grades :2 Grade 1 - - T h e femoral head subluxates during the manoeuver of Ortolani, after which it reduces into the acetabulum giving the 'click of entrance'. Pathologic anatomy consists of slightly enlarged capsule, hyperelastic limbus with normal shape of femoral head and acetubutum. Grade 2--Also demonstrate a positive Ortolani 'click of entrance', but the hip subluxates out spontaneously when the leg is left alone. Pathological anatomy consists of a defect in the superior/posterior acetabulum, a thickened elongated ligamentum teres, deformity of the femoral head, enlarged capsule, and a well developed acetabulum. 3. Ogden described three types of dislocation :3 Type 1 - - A subluxatable or positionally unstable hip, with mild lateral and marginal changes in the acetabulum. This hip would not manifest a true Ortolani sign, but would exhibit lack of complete abduction to 90 ° . Comprises 8090% of the overall C D H classification. Type 2--Subluxated, loss of sphericity of the femoral head, and anteversion. The acetabulum is shallower, with superior and posterior marginal deformities, especially progressive eversion of the labrum. Exhibits a 'clicking' sensation during Ortolani's manoeuver, as well as loss of full abduction. Type 3--Significant deformation ofacetabular margin and femoral head and posterior/superior displacement of the head to form a false acetabulum, along with progressive eversion of much of the labrum. During the first 2448 h, there frequently is sufficient laxity to manifest a 'clunking' sensation with Ortolani's manoeuver and concomitant dislocation during the Barlow manoeuver. Ponseti felt the ridge over which the femoral head exited was a ridge of acetabular hyaline cartilage in the usual type of hip dysplasia. 4 The labrum did not participate in the formation of this ridge, which appeared to be produced by the pressure of the subluxated femoral head on the outer margin of the acetabulum.
M c K i b b i n dissected the hips of a n e w b o r n male with C D H , without noting clinical findings. 5 The only pathologic finding of note was capsular laxity and an elongated ligamentum teres with a normal acetabulum and femoral head. Figure 1 illustrates the macroscopic findings in a male who died at 1 day of age of congenital heart disease and had been noted to have bilateral dislocatable hips prior to death. He also had marked capsular laxity with normal shape of the femoral head and acetabulum similar to the findings described by McKibbin. These dissections show a wide spectrum of pathological findings in the newborn with a dislocatable hip (the presence of a fixed dislocation at birth in a 'nonteratologic' hip is so rare that this condition will not be discussed). Hips like the example illustrated in Figure 1 and the one dissected by M c K i b b i n would probably respond rapidly to treatment, whereas those with acetabular deficiencies as described by Stanisavljevic would need longer treatment. However, it is difficult to correlate Ogden's findings with this scheme as his commonest group, Type 1, implies the presence of muscular contractures at birth, a finding not recorded by most authors. The problems with terminology also become apparent (for author's definitions (Table)). In the study by Gross and colleagues, the term subluxable (subluxatable is grammatically correct) implied that the femoral head did not exit from the acetabulum.6 A subluxation is, by definition, less than a dislocation. Subluxation as used by Stanisavljevic or Ogden is equivalent to the dislocatable hip of other authorities. These definitions are important. For example subluxatable hips as defined by Gross and colleagues were not treated and appeared to do very well. Thus Gross believes that Table--Definitions CDH
Dysplasia Dislocation
Dislocatable
Subluxatable
An all encompassingterm which includes dislocatable hips in the newborn, dislocated hips at any age, and dysplastic hips in the older infant or child. An abnormality of development of a particular structure. Implies the femoral head is completelyout of the true acetabulum. In th~ispaper, the term dislocation means fixeddislocation that cannot be reduced by the OrtolaniBarlow manoeuver. The femoral head may be reduced or dislocated by the Ortolani-Barlow manoeuver. No differentiation is attempted between hips that habitually reduce but are dislocatable, or hips that are habitually dislocated but reducible (recognising that the latter may well be more difficultto treat). The femoral head does not exit from the acetabulum though there is a feelingof excess mobilityof the joint; 'gliding over the ridge' of the femoral head exiting the acetabulum, the sensation described as 'scatto' by Ortolani or 'ressaut' by Le Damany is not felt.
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269
Fig. 1--(A) Dissected pelvis of a newborn male who was noted to have clinically dislocatable hips before death at 1 day of age. The right hip is abducted and reduced. (B) With posterior pressure, the femoral head slips over the posterior acetabulum. The degree of capsular laxity is evident. (C) The acetabulum is completely normal in configuration.
subluxatable hips will spontaneously stabilise. This is, however, still controversial. Nonetheless it is apparent that some hips can stabilise with no treatment, some hips may require only a very short period of treatment, but if acetabular and labral deficiencies are already present a much longer period of treatment may be necessary. Only periodic clinical examinations can help decide how long a period of splinting is needed. A number of splints have been described for treating the newborn hip. Most of them hold the hip in flexion and moderate abduction. Bucholz and Ogden have convincingly demonstrated the vulnerability of the blood supply of the infant cartilaginous femoral head in marked abduction and flexion 7 (Fig. 2). The medial circumflex artery, the primary source of vascularity to the chondroephiphysis, can be compressed at several sites in this position s (Fig. 3), and consequently marked abduction and flexion should be avoided. For this reason many authors now prefer non-rigid splints of which the Pavlik harness, which allows motion only in a controlled range, is presently the most popular. In C D H diagnosed at birth, this device has been very efficient, and avascular necrosis following its use at this age has only been reported after failure of the harness and additional treatment. The principles of using the Pavlik harness have been well described. 9,1° The hips should be flexed over 90°, but short of full forced flexion. The posterior strap should be adjusted to allow the knee to come within 3-5 cm of the mid-line. If there is any doubt over proper positioning in the harness, a radiograph can be
made. Trained nursing assistance can be extremely helpful in the management of C D H with the Pavtik harness, as parents are sometimes overwhelmed by the multiplicity of straps and attachments. The infant should be checked weekly for 3 weeks during which the hips usually stabilise, but the harness should be continued for an additional 3 weeks. At this point, some authors wean the harness over an additional 4-6 weeks. This is certainly a safe practice, although our routine, with stabilised hips, is to remove the harness at 6 weeks and X-ray the pelvis at 3 months. This will demonstrate any tendency towards subluxation. ('Fake care to ensure the hips and knees are extended; the pelvis flat, not hyperextended.) Follow-up radiographs are made at 6 and 12 months and then at infrequent intervals until skeletal maturity. If the hips are unstable at 6 weeks, radiographs in the harness are taken to ensure the hips are accurately centred. The harness is continued full-time for an additional ~ 6 weeks after attaining a stable reduction, and then weaned over an additional 4-6 week period. Continued follow-up is even more critical with these children.
Treatment After The Neonatal Period In addition to residual problems of management of the newborn, the following factors can result in later presentation of the various forms of C D H : 1. Diagnosis undetected at birth
270
THE CONSERVATIVE MANAGEMENT OF CONGENITAL DISLOCATION OF THE HIP 2. Primary acetabular dysplasia 3. Abduction contracture of the contralateral hip.
Fig. 2--Anterior portion of the femoral head of a 3 year, 4 month old boy. The ascending cervical artery (A) is a terminal branch of the medial circumflex artery, and any obstruction of the medial circumflex artery at any site will result in diminished flow to the growth center. Forced abduction can cause pressure at this site (A) by impinging on the labrum. The epiphyseal branches (B and C) are both terminal branches of the medial circumflex artery. (This figure is reproduced by kind permission of The Journal of Bone and Joint Surgery [ USA].)
The cause of failure of detection of all cases of C D H has recently been a matter of a great deal of speculation. One possible reason for a delayed diagnosis is the development of an abduction contracture of the contralateral hip. 11 (This can also be a nuisance during treatment of an already diagnosed CDH.) An abduction contracture is present if, on prone examination of the baby, it is impossible to adduct the contralateral hip to the mid-line. The other hip (the problem one) then lies in adduction which predisposes to acetabular dysplasia (not dislocation) due to the lack of the normal stimulus from the presence of the femoral head for normal acetabular development (Fig. 4). The importance of this relationship has been affirmed by evaluating acetabular shape after the insertion of titanium devices of various geometric configurations into puppies' acetabulae. ~2 With growth, the acetabulae assumed the shape of whatever was in it. Therefore, the radiographic appearance of acetabular dysplasia is evidence that the femoral head is not sufficiently well centered, and indicates the need for intervention. When an abduction contracture of the contralateral hip is found, stretching of the contracted hip, with or without use of the Pavlik harness, has been effective. In the absence of the contralateral abduction contracture, continued abduction splinting is indicated. Commercially available splints holding the hips in flexion and moderate (not 90 °) abduction are very satisfactory at this juncture (Fig. 5). Primary acetabular dysplasia, as described by Wynne-Davies, can also be managed with simple abduction splinting.13
Fig. 3 - - ( A ) Habitual prone position assumed by the child at this time was abduction of right hip and adduction of left hip. (B) Maximum adduction of right hip, lacking 20 ° of neutral position. (The thumb and index finger of the examiner indicate the lilac crest.) (C) Maximum adduction of left hip.
CURRENT ORTHOPAEDICS
Fig. 4~Easily applied commercial splint in a reasonable degree of abduction. This can only be applied after any adduction contracture is completely resolved.
The Pavlik harness has become accepted as an initial method of management for the dislocated hip with associated adductor contracture. However, the harness is more difficult to use and the risk of avascular necrosis is h i g h e ~ a reported incidence of 0 28~. 14,15 When managing this type of dislocated hip one should understand the concept of the 'safe zone'. 1o With the hip flexed, the safe zone is the angle formed between the degree of comfortable abduction and the degree at which dislocation occurs. Obviously, the greater the adduction contracture, the more restricted is the safe zone. A hasty attack on the adduction contracture by enthusiastic adjustment of the posterior strap to obtain abduction invites the advent of
~
avascular necrosis. The harness should initially be adjusted within the safe zone, however narrow, and the weight of the leg allowed to gently stretch the contracture. This method obviously demands careful attention and frequent monitoring. Radiographs should be made with each adjustment to ensure proper alignment of the femur toward the tri-radiate cartilage. Using this method successful reduction is attainable in the majority of children under 6 months on an outpatient basis. If a reduction is attained, the harness is worn full-time until the hip is stable; then a commercial abduction splint (which has much better parental acceptance) is continued initially on a fulltime basis, then used at night and during naps. Just as the underlying pathology may vary, the amount of necessary splinting may vary. As a guideline the harness is used full-time for 6 weeks after attaining reduction. Radiographs with the hip and knees extended are then taken. If the hip is not subluxated, abduction splinting is continued, with gradual weaning for an additional 3-6 months and even longer if acetabular dysplasia has not resolved. If reduction is not attained in 2-3 weeks, persistence is generally unrewarding. In the child less than 18 months of age, traction is usually the next step. As the principles of treatment by traction have become better defined, so the incidence of favorable results has increased. The article of Gage and Winter is 'must' reading before managing a child with traction for CDH. 16 The risk of avascular necrosis is minimised by achieving a position of the hip below the level of the normal hip (plus 2 station). Lesser degrees of distal
~ii" - ~iSAFE ~~::::,~'::'::~:~" ONE
REDISLOCATION -- /_.,~.:.:_::. _SAFE ":-~":':"
Z
271
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Fig. 5--(A) In the absence of contracture, such as in the newborn, a wide "safe zone" is availablefor adjustment of the Pavlik harness or any splint used to maintain reduction.(B) With adduction contracture, the safe zone is very narrow and precise adjustment of the harness is necessary. (This figure is reproduced by kind permission of The Journal of Bone and Joint Surgery [USAI.) (C) Adjustment of the Pavlik harness for attempted reduction of a fixed dislocation of the right hip. Reduction was not attained; the right hip was reduced by open reduction without complication.
272
THE CONSERVATIVE MANAGEMENT OF CONGENITAL DISLOCATION OF THE HIP
Fig. 6 - - ( A ) A 1-month-old girl with bilateral dislocatable Treatment with abduction splinting was successful.
hips.
Fig. 6 - - ( F ) The hips were immobilised for 6 weeks in greater than 90 ° of flexion and modest abduction. Fig. 6 - - ( B ) At 6 months, the hips appear well reduced.
Fig. 6 - - ( C ) At 8 months, subluxation has increased.
Fig. 6 - - ( G ) Abduction splinting at night was maintained for another year, and subluxation has decreased at 17 months.
Fig. 6 - - ( b ) Abduction splinting was recommended as the hips are well seated in the splint. The splint was not worn.
Fig. 6--(E) At 11 months, subluxation was marked.
Fig. 6 - - ( H ) At 3 plus 8, the hips are well formed.
displacement resulted in progressively higher rates of avascular necrosis. Skin traction at present seems to be more often used than skeletal traction, and programs for home traction are becoming popular as hospital costs soar.iT Skin traction is simpler, can be removed tbr bathing, has no infection risk when properly applied, and is easier to use at home. Disadvantages include the possibility of ulcers and ischemic complications when improperly applied, and the inability to use heavier weights. Skeletal traction has the advantage of a direct pull on the bone, allowing application of heavier traction if desired, but with the risk of pin tract infections. Persuasive advocates for both methods can be found. A rate of avascnlar necrosis of only 6 ~ in 319 hips treated with skin traction has been reported. 18 Others have found skin traction to be ineffective in that a pull equaling 39~ of body weight via skeletal traction was necessary to achieve the plus 2 station.19 When this was achieved, avascular necrosis did not occur in their series. Whatever traction is used, a plus 2 station should be achieved. If it is not, it is clear that
manipulative reduction is quite hazardous to the femoral head and open reduction should be considered. Traction regimens have been described with the hips flexed at 90 ° and progressively abducted, or longitudinally in a more extended position without progressive abduction. Although both methods appear to be efficacious, monitoring the position of the hip by guidelines described by Gage and Winter can only be performed when the hip is in a more extended position. After traction has reduced the contracture sufficiently, a closed reduction under anesthesia is performed. What is an adequate closed reduction ? Severin demonstrated arthrographically that interposed soft tissue can 'melt away' if reduction is imperfect, but the femoral head is pointed toward the tri-radiate cartilage. 2° Others have disputed this, demonstrating inferior results when a well centered concentric closed reduction was not obtained. 21 Race and Herring, in a carefully studied group of patients, concluded that a medial dye pool of up to 7 mm could be accepted if the hip could be held in a reduced position without force. 22 If this cannot be achieved after adductor
CURRENT ORTHOPAEDICS 273
Fig. 7 - - ( A ) A fixed dislocation of the right hip in a 1 plus 6year-old girl.
Fig. 7--(B) 'Plus two' station of Gage and Winter achieved with skeletal traction.
Fig. 7--(C) Stable reduction was achieved and a Pavlik harness was used for further immobilisation. Although successful here, this child is too large for reliable usage of the Pavlik harness.
tenotomy, open reduction is recommended. They reiterated the advice of Severin given in 1941 that a repeat arthrogram several months later is of inestimable value in assessing the hip. It will demonstrate the need for continued splinting if a medial dye pool persists; it can reassure the surgeon that no obstacle to reduction exists when acetabular dysplasia responds slowly to treatment; or it may indicate the need for an open reduction by showing an obstacle to reduction. It is important to recognise that while traction and closed reduction can often be successful, it may not always be successful, and that one should not persist when an obstacle to concentric reduction lingers on. After successful closed reduction, the hip should be immobilised in a position of stability without tension, the so-called 'human position', with greater than 90 ° of flexion but only 30 50 ° of abduction. Applying a cast to the infant in this position involves considerable care, as there is a tendency to extend the hips for easier application. A firm mould should be placed under the greater trochanter to combat posterior displacement. The duration of splinting with closed management cannot be reliably calculated by formulas based on age. Once the bony acetabulum shows a definite improvement, and the hip is well centered by standard radiographic assessments, slblinting can be generally reduced to part-time usage until the acetabular
Fig. 7--(D) Ten months later, night splinting was still used.
Fig. 7--(E) Splinting discontinued at age 3 years.
Fig. 7--(F) Continued acetabular remodeling evident at age 6 plus 7.
dysplasia is resolved. If splinting is discontinued, hip status should be carefully observed during this phase of development as deterioration is still possible (Fig.
6).
Complications If the goal of treatment is to attain and maintain reduction, the most common failure is not achieving this goal. With newer radiographic techniques, including arthrography, computerised tomography (o1" a combination of the two), it is possible to ascertain the quality of the reduction accurately. While it is acceptable to continue with closed management when 5-7 mm of lateral displacement of the femoral head is present, it is not acceptable to continue conservative management when the femoral head is not aligned in the direction of the tri-radiate cartilage or if the lateral displacement persists after 6 12 weeks of immobitisation. 22 It is not wise to rigidly adhere to a fixed treatment plan for every child with CDH. Some hips, on the basis of their underlying pathology, will respond well to management with a Pavlik, others will not. Some contractures can be overcome with traction and a safe concentric closed reduction can be performed. If the contracture is recalcitrant and a reduction cannot be achieved, a non-traumatic open reduction is indicated. It is important to treat the femoral head gently, and
274 THE C O N S E R V A T I V E M A N A G E M E N T OF C O N G E N I T A L DISLOCATION OF THE HIP
Fig. 8--(A) A fixed dislocation of the left hip in a 4-month-old girl,
Fig. 8--(D) At 2 plus 8, there is good position of the hips.
Fig. 8--(B) "Plus two' station of Gage and Winter achieved by skeletal traction.
Fig. 8--(E) At 7 plus 1, shortening of the lateral neck is evident,
Fig. 8--(C) Radiograph at the time of reduction. The degree of abduction in which the hips were immobilised is not clear.
Fig. 8--(F) Further deformity is evident in later childhood.
regard the vascular supply as a precious commodity. Immobilising a dysplastic hip in a subluxated or dislocated position increases the risk of ischemic necrosis, by increased tension on the vascular supply. Immobilisation in marked abduction even if adequate traction has previously been achieved, can result in ischemic necrosis of the vulnerable posterior superior artery to the epiphysis with resultant lateral growth arrest (Figs. 7 and 8). This complication may not be noticeable until late childhood, emphasising the need for follow-up of all children treated for CDH until skeletal maturity.
References 1. Dunn P M 1976 Perinatal observations on the etiology of congenital dislocation of the hip. Clinical Orthopaedics 119 : 11 22 2. Stanisavljevic S 1982 Part II, Anatomy of congenital hip pathology. In: Tachdjian M O (ed) Congenital dislocation of the hip. Churchill Livingstone, New York pp 34-57 3. Ogden J A 1982 Dynamic pathobiology of congenital hip dysplasia. In: Tachdjian M O (ed) Congenital dislocation of the hip. Churchill Livingstone, New York pp 93-144. 4. Ponseti I V 1978 Morphology of the acetabulum in congenital dislocation of the hip. Journal of Bone and Joint Surgery 60-A : 586-599 5. McKibbin B 1970 Anatomical factors in the stabilityofthe hip joint in newborn. Journal of Bone and Joint Surgery 52-B : 148-159 6. Gross R H, Wisnefske M, Howard T C, Hitch M Infant hip screening in the hip. Vol 10, C V Mosby, St Louis pp 50-67 7. Bucholz R W, Ogden J A 1978 Patterns of ischemic necrosis of the proximal femur in nonoperatively treated congenital hip disease. In: The Hip Vol 6, C V Mosby, St Louis pp 43 63 8. Chung S M K 1976 The arterial supply of the developing proximal end of the femur. Journal of Bone and Joint Surgery 58-A: 961-970 9. Mubarak S, Garfin S, Vance R, McKinnon B, Sutherland D 1980 Pitfalls in the use of the Pavlik harness for treatment of
indicating ischemic necrosis of the lateral epiphyseal vessels.
10.
11.
12. 13. 14. 15. 16.
17. 18.
19.
20. 21. 22.
congenital dysplasia, subluxation, and dislocation of the hip. Journal of Bone and Joint Surgery 63-A: 1239 1248 Ramsey P L, Lasser S, MacEwen G D 1976 Congenital dislocation of the hip. Use of the Pavlik harness in the child during the first six months of life. Journal of Bone and Joint Surgery 58-A: 1000 1004 Green N E, Griffin P P 1982 Hip dysplasia associated with abduction contracture of the contralateral hip. Journal of Bone and Joint Surgery 64-A : 1273--1281 Coleman C R, Slager K F, Smith W S 1959 The effect of environmental influence on acetabular development. Surgical Forum 9 : 775 780 Wynne-Davies R 1970 Acetabular dysplasia and familial ioint laxity: Two etiological factors in congenital dislocation of the hip. Journal of Bone and Joint Surgery 52-B: 704 716 IwasakiI 1983 Treatment of congenital dislocation of the hip by the Pavlik harness. Mechanism of Reduction and Usage. Journal of Bone and Joint Surgery 65-A: 760-767 Kalamchi A, MacFarlane R 1982 The Pavtik harness : Results in patients over three months of age. Journal of Pediatric Orthopedics 2: 3-8 Gage J R, Winter R B 1972 Avascular necrosis of the capital femoral epiphysis as a complication of closed reduction of congenital dislocation of the hip. Journal of Bone and Joint Surgery 54-A : 373-388 Joseph K, MacEwen G D, Boos M L 1982 Home traction in the management of congenital dislocation of the hip. Clinical Orthopaedics 165:83 90 Weiner D S, Hoyt W A Jr, O'Dell H W 1977 Congenital dislocation of the hip. The relationship of premanipulation traction and age to avascular necrosis of the femoral head. Journal of Bone and Joint Surgery 59-A : 306-311 Buchanan J R, Greer R B, Cotler J M Management strategies for prevention of avascular necrosis during treatment of congenital dislocation of the hip. Journal of Bone and Joint Surgery 63-A : 140-146 Severin E 1950 Congenital dislocation of the hip. Development of the joint after closed reduction. Journal of Bone and Joint Surgery 32-A: 507 518 R e n s h a w T S 1981 Inadequate reduction of congenital dislocation of the hip. Journal of Bone and Joint Surgery 63-A : 1114 1121 Race C, Herring J A 1983 Congenital dislocation of the hip: an evaluation of closed reduction. Journal of Pediatric Orthopedics 3 : 166-172
R. H. Gross
As a result of early diagnosis of C D H conservative treatment has become increasingly important since the majority of children will be at an age when operative treatment is not necessary. In spite of this major achievement, a number of uncertainties and conflicting opinions still shroud a clear understanding of the problem of C D H in this age group. This paper attempts to analyse our present knowledge in a manner which will allow the orthopaedist to formulate a treatment plan on the basis of available information rather than dogmatic principles. The two essential treatment goals are: 1. Attain and maintain reduction. 2. Avoid avascular necrosis. Any strategy must take into account: 1. Age 2. Variations in intra-articular pathology 3. Presence or absence of contractures. Other more poorly understood factors such as individual variations in blood supply to the femoral head may also influence the result. This discussion will exclude the 'teratologic' hip with fixed contractures and capsular constriction, as these hips cannot be managed non-operatively.
Although it is recognised that many dislocatable hips discovered by Ortolani-Barlow manoeuver will stabilise without treatment and progress into normal hips, most authorities recommend treatment of this type of hip instability. If treatment is deferred it is imperative that careful follow-up be maintained during the 1st year of life, especially for the first 3 months. The factors determining which hips will spontaneously stabilise are not fully understood. Differences in pathological anatomy are important and some insight is provided from dissections of stillborn babies. Even when teratologic hips are excluded there is considerable variation in the descriptions of the
Treatment O f The Neonate Although treatment of CDH is simpler and more gratifying in the newborn than at any other time certain key questions do not presently have defined answers. These are: 1. What is the pathological anatomy of the dislocatable hip ? 2. Which hips must be treated? 3. If treated, how long should splinting be applied? 4~ How can complications be avoided? Richard H. Gross M D , Department of Orthopaedics, College of Medicine, University of Florida, Box J-246, J H M Health Center, Gainesville, Florida 32610, USA. Current Orthopaedics (1987)i, 267 274 © 1987LongmanGroup UK Ltd
267
268
THE CONSERVATIVE MANAGEMENT OF CONGENITAL DISLOCATION OF THE HIP
'normal C D H ' by the various authors. Their findings using their own terminology are as follows: 1. Dunn described three grades :1 Grade 1 - - T h e dislocatable hip in which the basic pathology is instability of the limbus, allowing dislocation. Grade 2 - - T h e limbus is everted, the femoral head no longer spherical. Grade 3 - - T h e limbus is inverted to form the floor of a false acetabulum. 2. Stanisavljevic defined two grades :2 Grade 1 - - T h e femoral head subluxates during the manoeuver of Ortolani, after which it reduces into the acetabulum giving the 'click of entrance'. Pathologic anatomy consists of slightly enlarged capsule, hyperelastic limbus with normal shape of femoral head and acetubutum. Grade 2--Also demonstrate a positive Ortolani 'click of entrance', but the hip subluxates out spontaneously when the leg is left alone. Pathological anatomy consists of a defect in the superior/posterior acetabulum, a thickened elongated ligamentum teres, deformity of the femoral head, enlarged capsule, and a well developed acetabulum. 3. Ogden described three types of dislocation :3 Type 1 - - A subluxatable or positionally unstable hip, with mild lateral and marginal changes in the acetabulum. This hip would not manifest a true Ortolani sign, but would exhibit lack of complete abduction to 90 ° . Comprises 8090% of the overall C D H classification. Type 2--Subluxated, loss of sphericity of the femoral head, and anteversion. The acetabulum is shallower, with superior and posterior marginal deformities, especially progressive eversion of the labrum. Exhibits a 'clicking' sensation during Ortolani's manoeuver, as well as loss of full abduction. Type 3--Significant deformation ofacetabular margin and femoral head and posterior/superior displacement of the head to form a false acetabulum, along with progressive eversion of much of the labrum. During the first 2448 h, there frequently is sufficient laxity to manifest a 'clunking' sensation with Ortolani's manoeuver and concomitant dislocation during the Barlow manoeuver. Ponseti felt the ridge over which the femoral head exited was a ridge of acetabular hyaline cartilage in the usual type of hip dysplasia. 4 The labrum did not participate in the formation of this ridge, which appeared to be produced by the pressure of the subluxated femoral head on the outer margin of the acetabulum.
M c K i b b i n dissected the hips of a n e w b o r n male with C D H , without noting clinical findings. 5 The only pathologic finding of note was capsular laxity and an elongated ligamentum teres with a normal acetabulum and femoral head. Figure 1 illustrates the macroscopic findings in a male who died at 1 day of age of congenital heart disease and had been noted to have bilateral dislocatable hips prior to death. He also had marked capsular laxity with normal shape of the femoral head and acetabulum similar to the findings described by McKibbin. These dissections show a wide spectrum of pathological findings in the newborn with a dislocatable hip (the presence of a fixed dislocation at birth in a 'nonteratologic' hip is so rare that this condition will not be discussed). Hips like the example illustrated in Figure 1 and the one dissected by M c K i b b i n would probably respond rapidly to treatment, whereas those with acetabular deficiencies as described by Stanisavljevic would need longer treatment. However, it is difficult to correlate Ogden's findings with this scheme as his commonest group, Type 1, implies the presence of muscular contractures at birth, a finding not recorded by most authors. The problems with terminology also become apparent (for author's definitions (Table)). In the study by Gross and colleagues, the term subluxable (subluxatable is grammatically correct) implied that the femoral head did not exit from the acetabulum.6 A subluxation is, by definition, less than a dislocation. Subluxation as used by Stanisavljevic or Ogden is equivalent to the dislocatable hip of other authorities. These definitions are important. For example subluxatable hips as defined by Gross and colleagues were not treated and appeared to do very well. Thus Gross believes that Table--Definitions CDH
Dysplasia Dislocation
Dislocatable
Subluxatable
An all encompassingterm which includes dislocatable hips in the newborn, dislocated hips at any age, and dysplastic hips in the older infant or child. An abnormality of development of a particular structure. Implies the femoral head is completelyout of the true acetabulum. In th~ispaper, the term dislocation means fixeddislocation that cannot be reduced by the OrtolaniBarlow manoeuver. The femoral head may be reduced or dislocated by the Ortolani-Barlow manoeuver. No differentiation is attempted between hips that habitually reduce but are dislocatable, or hips that are habitually dislocated but reducible (recognising that the latter may well be more difficultto treat). The femoral head does not exit from the acetabulum though there is a feelingof excess mobilityof the joint; 'gliding over the ridge' of the femoral head exiting the acetabulum, the sensation described as 'scatto' by Ortolani or 'ressaut' by Le Damany is not felt.
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269
Fig. 1--(A) Dissected pelvis of a newborn male who was noted to have clinically dislocatable hips before death at 1 day of age. The right hip is abducted and reduced. (B) With posterior pressure, the femoral head slips over the posterior acetabulum. The degree of capsular laxity is evident. (C) The acetabulum is completely normal in configuration.
subluxatable hips will spontaneously stabilise. This is, however, still controversial. Nonetheless it is apparent that some hips can stabilise with no treatment, some hips may require only a very short period of treatment, but if acetabular and labral deficiencies are already present a much longer period of treatment may be necessary. Only periodic clinical examinations can help decide how long a period of splinting is needed. A number of splints have been described for treating the newborn hip. Most of them hold the hip in flexion and moderate abduction. Bucholz and Ogden have convincingly demonstrated the vulnerability of the blood supply of the infant cartilaginous femoral head in marked abduction and flexion 7 (Fig. 2). The medial circumflex artery, the primary source of vascularity to the chondroephiphysis, can be compressed at several sites in this position s (Fig. 3), and consequently marked abduction and flexion should be avoided. For this reason many authors now prefer non-rigid splints of which the Pavlik harness, which allows motion only in a controlled range, is presently the most popular. In C D H diagnosed at birth, this device has been very efficient, and avascular necrosis following its use at this age has only been reported after failure of the harness and additional treatment. The principles of using the Pavlik harness have been well described. 9,1° The hips should be flexed over 90°, but short of full forced flexion. The posterior strap should be adjusted to allow the knee to come within 3-5 cm of the mid-line. If there is any doubt over proper positioning in the harness, a radiograph can be
made. Trained nursing assistance can be extremely helpful in the management of C D H with the Pavtik harness, as parents are sometimes overwhelmed by the multiplicity of straps and attachments. The infant should be checked weekly for 3 weeks during which the hips usually stabilise, but the harness should be continued for an additional 3 weeks. At this point, some authors wean the harness over an additional 4-6 weeks. This is certainly a safe practice, although our routine, with stabilised hips, is to remove the harness at 6 weeks and X-ray the pelvis at 3 months. This will demonstrate any tendency towards subluxation. ('Fake care to ensure the hips and knees are extended; the pelvis flat, not hyperextended.) Follow-up radiographs are made at 6 and 12 months and then at infrequent intervals until skeletal maturity. If the hips are unstable at 6 weeks, radiographs in the harness are taken to ensure the hips are accurately centred. The harness is continued full-time for an additional ~ 6 weeks after attaining a stable reduction, and then weaned over an additional 4-6 week period. Continued follow-up is even more critical with these children.
Treatment After The Neonatal Period In addition to residual problems of management of the newborn, the following factors can result in later presentation of the various forms of C D H : 1. Diagnosis undetected at birth
270
THE CONSERVATIVE MANAGEMENT OF CONGENITAL DISLOCATION OF THE HIP 2. Primary acetabular dysplasia 3. Abduction contracture of the contralateral hip.
Fig. 2--Anterior portion of the femoral head of a 3 year, 4 month old boy. The ascending cervical artery (A) is a terminal branch of the medial circumflex artery, and any obstruction of the medial circumflex artery at any site will result in diminished flow to the growth center. Forced abduction can cause pressure at this site (A) by impinging on the labrum. The epiphyseal branches (B and C) are both terminal branches of the medial circumflex artery. (This figure is reproduced by kind permission of The Journal of Bone and Joint Surgery [ USA].)
The cause of failure of detection of all cases of C D H has recently been a matter of a great deal of speculation. One possible reason for a delayed diagnosis is the development of an abduction contracture of the contralateral hip. 11 (This can also be a nuisance during treatment of an already diagnosed CDH.) An abduction contracture is present if, on prone examination of the baby, it is impossible to adduct the contralateral hip to the mid-line. The other hip (the problem one) then lies in adduction which predisposes to acetabular dysplasia (not dislocation) due to the lack of the normal stimulus from the presence of the femoral head for normal acetabular development (Fig. 4). The importance of this relationship has been affirmed by evaluating acetabular shape after the insertion of titanium devices of various geometric configurations into puppies' acetabulae. ~2 With growth, the acetabulae assumed the shape of whatever was in it. Therefore, the radiographic appearance of acetabular dysplasia is evidence that the femoral head is not sufficiently well centered, and indicates the need for intervention. When an abduction contracture of the contralateral hip is found, stretching of the contracted hip, with or without use of the Pavlik harness, has been effective. In the absence of the contralateral abduction contracture, continued abduction splinting is indicated. Commercially available splints holding the hips in flexion and moderate (not 90 °) abduction are very satisfactory at this juncture (Fig. 5). Primary acetabular dysplasia, as described by Wynne-Davies, can also be managed with simple abduction splinting.13
Fig. 3 - - ( A ) Habitual prone position assumed by the child at this time was abduction of right hip and adduction of left hip. (B) Maximum adduction of right hip, lacking 20 ° of neutral position. (The thumb and index finger of the examiner indicate the lilac crest.) (C) Maximum adduction of left hip.
CURRENT ORTHOPAEDICS
Fig. 4~Easily applied commercial splint in a reasonable degree of abduction. This can only be applied after any adduction contracture is completely resolved.
The Pavlik harness has become accepted as an initial method of management for the dislocated hip with associated adductor contracture. However, the harness is more difficult to use and the risk of avascular necrosis is h i g h e ~ a reported incidence of 0 28~. 14,15 When managing this type of dislocated hip one should understand the concept of the 'safe zone'. 1o With the hip flexed, the safe zone is the angle formed between the degree of comfortable abduction and the degree at which dislocation occurs. Obviously, the greater the adduction contracture, the more restricted is the safe zone. A hasty attack on the adduction contracture by enthusiastic adjustment of the posterior strap to obtain abduction invites the advent of
~
avascular necrosis. The harness should initially be adjusted within the safe zone, however narrow, and the weight of the leg allowed to gently stretch the contracture. This method obviously demands careful attention and frequent monitoring. Radiographs should be made with each adjustment to ensure proper alignment of the femur toward the tri-radiate cartilage. Using this method successful reduction is attainable in the majority of children under 6 months on an outpatient basis. If a reduction is attained, the harness is worn full-time until the hip is stable; then a commercial abduction splint (which has much better parental acceptance) is continued initially on a fulltime basis, then used at night and during naps. Just as the underlying pathology may vary, the amount of necessary splinting may vary. As a guideline the harness is used full-time for 6 weeks after attaining reduction. Radiographs with the hip and knees extended are then taken. If the hip is not subluxated, abduction splinting is continued, with gradual weaning for an additional 3-6 months and even longer if acetabular dysplasia has not resolved. If reduction is not attained in 2-3 weeks, persistence is generally unrewarding. In the child less than 18 months of age, traction is usually the next step. As the principles of treatment by traction have become better defined, so the incidence of favorable results has increased. The article of Gage and Winter is 'must' reading before managing a child with traction for CDH. 16 The risk of avascular necrosis is minimised by achieving a position of the hip below the level of the normal hip (plus 2 station). Lesser degrees of distal
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REDISLOCATION -- /_.,~.:.:_::. _SAFE ":-~":':"
Z
271
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Fig. 5--(A) In the absence of contracture, such as in the newborn, a wide "safe zone" is availablefor adjustment of the Pavlik harness or any splint used to maintain reduction.(B) With adduction contracture, the safe zone is very narrow and precise adjustment of the harness is necessary. (This figure is reproduced by kind permission of The Journal of Bone and Joint Surgery [USAI.) (C) Adjustment of the Pavlik harness for attempted reduction of a fixed dislocation of the right hip. Reduction was not attained; the right hip was reduced by open reduction without complication.
272
THE CONSERVATIVE MANAGEMENT OF CONGENITAL DISLOCATION OF THE HIP
Fig. 6 - - ( A ) A 1-month-old girl with bilateral dislocatable Treatment with abduction splinting was successful.
hips.
Fig. 6 - - ( F ) The hips were immobilised for 6 weeks in greater than 90 ° of flexion and modest abduction. Fig. 6 - - ( B ) At 6 months, the hips appear well reduced.
Fig. 6 - - ( C ) At 8 months, subluxation has increased.
Fig. 6 - - ( G ) Abduction splinting at night was maintained for another year, and subluxation has decreased at 17 months.
Fig. 6 - - ( b ) Abduction splinting was recommended as the hips are well seated in the splint. The splint was not worn.
Fig. 6--(E) At 11 months, subluxation was marked.
Fig. 6 - - ( H ) At 3 plus 8, the hips are well formed.
displacement resulted in progressively higher rates of avascular necrosis. Skin traction at present seems to be more often used than skeletal traction, and programs for home traction are becoming popular as hospital costs soar.iT Skin traction is simpler, can be removed tbr bathing, has no infection risk when properly applied, and is easier to use at home. Disadvantages include the possibility of ulcers and ischemic complications when improperly applied, and the inability to use heavier weights. Skeletal traction has the advantage of a direct pull on the bone, allowing application of heavier traction if desired, but with the risk of pin tract infections. Persuasive advocates for both methods can be found. A rate of avascnlar necrosis of only 6 ~ in 319 hips treated with skin traction has been reported. 18 Others have found skin traction to be ineffective in that a pull equaling 39~ of body weight via skeletal traction was necessary to achieve the plus 2 station.19 When this was achieved, avascular necrosis did not occur in their series. Whatever traction is used, a plus 2 station should be achieved. If it is not, it is clear that
manipulative reduction is quite hazardous to the femoral head and open reduction should be considered. Traction regimens have been described with the hips flexed at 90 ° and progressively abducted, or longitudinally in a more extended position without progressive abduction. Although both methods appear to be efficacious, monitoring the position of the hip by guidelines described by Gage and Winter can only be performed when the hip is in a more extended position. After traction has reduced the contracture sufficiently, a closed reduction under anesthesia is performed. What is an adequate closed reduction ? Severin demonstrated arthrographically that interposed soft tissue can 'melt away' if reduction is imperfect, but the femoral head is pointed toward the tri-radiate cartilage. 2° Others have disputed this, demonstrating inferior results when a well centered concentric closed reduction was not obtained. 21 Race and Herring, in a carefully studied group of patients, concluded that a medial dye pool of up to 7 mm could be accepted if the hip could be held in a reduced position without force. 22 If this cannot be achieved after adductor
CURRENT ORTHOPAEDICS 273
Fig. 7 - - ( A ) A fixed dislocation of the right hip in a 1 plus 6year-old girl.
Fig. 7--(B) 'Plus two' station of Gage and Winter achieved with skeletal traction.
Fig. 7--(C) Stable reduction was achieved and a Pavlik harness was used for further immobilisation. Although successful here, this child is too large for reliable usage of the Pavlik harness.
tenotomy, open reduction is recommended. They reiterated the advice of Severin given in 1941 that a repeat arthrogram several months later is of inestimable value in assessing the hip. It will demonstrate the need for continued splinting if a medial dye pool persists; it can reassure the surgeon that no obstacle to reduction exists when acetabular dysplasia responds slowly to treatment; or it may indicate the need for an open reduction by showing an obstacle to reduction. It is important to recognise that while traction and closed reduction can often be successful, it may not always be successful, and that one should not persist when an obstacle to concentric reduction lingers on. After successful closed reduction, the hip should be immobilised in a position of stability without tension, the so-called 'human position', with greater than 90 ° of flexion but only 30 50 ° of abduction. Applying a cast to the infant in this position involves considerable care, as there is a tendency to extend the hips for easier application. A firm mould should be placed under the greater trochanter to combat posterior displacement. The duration of splinting with closed management cannot be reliably calculated by formulas based on age. Once the bony acetabulum shows a definite improvement, and the hip is well centered by standard radiographic assessments, slblinting can be generally reduced to part-time usage until the acetabular
Fig. 7--(D) Ten months later, night splinting was still used.
Fig. 7--(E) Splinting discontinued at age 3 years.
Fig. 7--(F) Continued acetabular remodeling evident at age 6 plus 7.
dysplasia is resolved. If splinting is discontinued, hip status should be carefully observed during this phase of development as deterioration is still possible (Fig.
6).
Complications If the goal of treatment is to attain and maintain reduction, the most common failure is not achieving this goal. With newer radiographic techniques, including arthrography, computerised tomography (o1" a combination of the two), it is possible to ascertain the quality of the reduction accurately. While it is acceptable to continue with closed management when 5-7 mm of lateral displacement of the femoral head is present, it is not acceptable to continue conservative management when the femoral head is not aligned in the direction of the tri-radiate cartilage or if the lateral displacement persists after 6 12 weeks of immobitisation. 22 It is not wise to rigidly adhere to a fixed treatment plan for every child with CDH. Some hips, on the basis of their underlying pathology, will respond well to management with a Pavlik, others will not. Some contractures can be overcome with traction and a safe concentric closed reduction can be performed. If the contracture is recalcitrant and a reduction cannot be achieved, a non-traumatic open reduction is indicated. It is important to treat the femoral head gently, and
274 THE C O N S E R V A T I V E M A N A G E M E N T OF C O N G E N I T A L DISLOCATION OF THE HIP
Fig. 8--(A) A fixed dislocation of the left hip in a 4-month-old girl,
Fig. 8--(D) At 2 plus 8, there is good position of the hips.
Fig. 8--(B) "Plus two' station of Gage and Winter achieved by skeletal traction.
Fig. 8--(E) At 7 plus 1, shortening of the lateral neck is evident,
Fig. 8--(C) Radiograph at the time of reduction. The degree of abduction in which the hips were immobilised is not clear.
Fig. 8--(F) Further deformity is evident in later childhood.
regard the vascular supply as a precious commodity. Immobilising a dysplastic hip in a subluxated or dislocated position increases the risk of ischemic necrosis, by increased tension on the vascular supply. Immobilisation in marked abduction even if adequate traction has previously been achieved, can result in ischemic necrosis of the vulnerable posterior superior artery to the epiphysis with resultant lateral growth arrest (Figs. 7 and 8). This complication may not be noticeable until late childhood, emphasising the need for follow-up of all children treated for CDH until skeletal maturity.
References 1. Dunn P M 1976 Perinatal observations on the etiology of congenital dislocation of the hip. Clinical Orthopaedics 119 : 11 22 2. Stanisavljevic S 1982 Part II, Anatomy of congenital hip pathology. In: Tachdjian M O (ed) Congenital dislocation of the hip. Churchill Livingstone, New York pp 34-57 3. Ogden J A 1982 Dynamic pathobiology of congenital hip dysplasia. In: Tachdjian M O (ed) Congenital dislocation of the hip. Churchill Livingstone, New York pp 93-144. 4. Ponseti I V 1978 Morphology of the acetabulum in congenital dislocation of the hip. Journal of Bone and Joint Surgery 60-A : 586-599 5. McKibbin B 1970 Anatomical factors in the stabilityofthe hip joint in newborn. Journal of Bone and Joint Surgery 52-B : 148-159 6. Gross R H, Wisnefske M, Howard T C, Hitch M Infant hip screening in the hip. Vol 10, C V Mosby, St Louis pp 50-67 7. Bucholz R W, Ogden J A 1978 Patterns of ischemic necrosis of the proximal femur in nonoperatively treated congenital hip disease. In: The Hip Vol 6, C V Mosby, St Louis pp 43 63 8. Chung S M K 1976 The arterial supply of the developing proximal end of the femur. Journal of Bone and Joint Surgery 58-A: 961-970 9. Mubarak S, Garfin S, Vance R, McKinnon B, Sutherland D 1980 Pitfalls in the use of the Pavlik harness for treatment of
indicating ischemic necrosis of the lateral epiphyseal vessels.
10.
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20. 21. 22.
congenital dysplasia, subluxation, and dislocation of the hip. Journal of Bone and Joint Surgery 63-A: 1239 1248 Ramsey P L, Lasser S, MacEwen G D 1976 Congenital dislocation of the hip. Use of the Pavlik harness in the child during the first six months of life. Journal of Bone and Joint Surgery 58-A: 1000 1004 Green N E, Griffin P P 1982 Hip dysplasia associated with abduction contracture of the contralateral hip. Journal of Bone and Joint Surgery 64-A : 1273--1281 Coleman C R, Slager K F, Smith W S 1959 The effect of environmental influence on acetabular development. Surgical Forum 9 : 775 780 Wynne-Davies R 1970 Acetabular dysplasia and familial ioint laxity: Two etiological factors in congenital dislocation of the hip. Journal of Bone and Joint Surgery 52-B: 704 716 IwasakiI 1983 Treatment of congenital dislocation of the hip by the Pavlik harness. Mechanism of Reduction and Usage. Journal of Bone and Joint Surgery 65-A: 760-767 Kalamchi A, MacFarlane R 1982 The Pavtik harness : Results in patients over three months of age. Journal of Pediatric Orthopedics 2: 3-8 Gage J R, Winter R B 1972 Avascular necrosis of the capital femoral epiphysis as a complication of closed reduction of congenital dislocation of the hip. Journal of Bone and Joint Surgery 54-A : 373-388 Joseph K, MacEwen G D, Boos M L 1982 Home traction in the management of congenital dislocation of the hip. Clinical Orthopaedics 165:83 90 Weiner D S, Hoyt W A Jr, O'Dell H W 1977 Congenital dislocation of the hip. The relationship of premanipulation traction and age to avascular necrosis of the femoral head. Journal of Bone and Joint Surgery 59-A : 306-311 Buchanan J R, Greer R B, Cotler J M Management strategies for prevention of avascular necrosis during treatment of congenital dislocation of the hip. Journal of Bone and Joint Surgery 63-A : 140-146 Severin E 1950 Congenital dislocation of the hip. Development of the joint after closed reduction. Journal of Bone and Joint Surgery 32-A: 507 518 R e n s h a w T S 1981 Inadequate reduction of congenital dislocation of the hip. Journal of Bone and Joint Surgery 63-A : 1114 1121 Race C, Herring J A 1983 Congenital dislocation of the hip: an evaluation of closed reduction. Journal of Pediatric Orthopedics 3 : 166-172