Subluxation of the hip presenting for the first time

Transcription

1 The treatment of subluxation of the hip in children over the age of four years John A. Fixsen, Patrick L. S. Li From the Hospitals for Sick Children, Great Ormond Street, London, England Subluxation of the hip presenting for the first time in a child over the age of four years is rare. We report ten cases treated over nearly 11 years by the senior author (JAF). We describe the surgical procedures and the results, at maturity, of nine of the ten patients. At a mean follow-up of nearly nine years, the clinical outcome was good in all ten children by the criteria of Ponseti. Radiological assessment showed that three hips remained subluxed, and that four had avascular necrosis of the physis. We advise a one-stage procedure, correcting both the femur and acetabulum. J Bone Joint Surg [Br] 1998;80-B: Received 22 December 1997; Accepted after revision 24 March 1998 The term developmental dysplasia of the hip (DDH) covers a range of infantile hip disorders from minor acetabular dysplasia to full dislocation. 1 Within this spectrum subluxation, in which the femoral head remains in partial contact with the articular surface of the acetabulum, is a distinct entity. Clinical screening for DDH may reveal a positive Ortolani sign, 2 consistent with full, but reducible dislocation, or a positive Barlow sign 3 in the presence of a dislocatable hip. Both signs may be absent in subluxation. The diagnosis may therefore be missed during screening, particularly in the absence of limitation of abduction. It has been argued that subluxation is a diagnosis that can only be established by arthrography 4 or ultrasound. 5 It is generally accepted that the best time to treat DDH is at birth. 2 Screening programmes, however, have not been infallible or without their difficulties. 6 As a result, a number of children continue to present late with subluxation of the hip (Fig. 1). Review of the literature has revealed little J. A. Fixsen, MCh, FRCS, Consultant Orthopaedic Surgeon The Hospitals for Sick Children, Great Ormond Street, London WC1N 3JH, UK. P. L. S. Li, FRCS Orth, Clinical Lecturer in Orthopaedics Institute of Orthopaedics, The Royal National Orthopaedic Hospital Trust, Brockley Hill, Stanmore, Middlesex HA7 4LP, UK. Correspondence should be sent to Mr P. L. S. Li British Editorial Society of Bone and Joint Surgery X/98/58671 $2.00 information on the best method of treatment of this rare, but challenging, group of patients and on their long-term outcome. We report a series of ten children with late subluxation of the hip presenting over the age of four years. Patients and Methods Between February 1979 and October 1989, ten children, aged over four years, were referred to the senior author (JAF) for subluxation of a hip. The youngest was 4.5 years old at the time of diagnosis and the oldest, 7.5 years. With one exception, they had all been born in the UK and no abnormalities had been detected during screening in the first year of life. One patient was born of English parents in Kenya, and it is not clear whether her hips had been screened. There were nine girls and one boy. All had unilateral subluxation of the hip, four left-sided and six on the right. All presented with a limp. Abnormality of the skin creases was noted in only one patient. Limitation of abduction was present in three hips, but was not a prominent feature. Operative treatment. The details of the operations performed are shown in Table I. Five of the ten children required only one set of procedures, carried out either in one or two stages at an interval of six weeks. The remaining five children required further surgery several months or years later. Primary procedures. Preliminary traction was not used. All patients had open reduction during which any tight softtissue structures, such as the iliopsoas and adductors, were divided to give reduction without tension. A capsulotomy was performed in nine patients to allow removal of softtissue obstructions such as the transverse acetabular ligament, the pulvinar and a hypertrophic ligamentum teres. In one hip, capsulotomy was not necessary since a satisfactory reduction was obtained without any evidence of intraarticular obstruction. After reduction the position of maximum stability was assessed clinically by the surgeon in order to determine whether an additional pelvic or femoral osteotomy was required. In six hips, a femoral derotational osteotomy was necessary to compensate for excessive anteversion of the femoral neck. Femoral shortening was carried out at the same time in two hips. In three, a pelvic VOL. 80-B, NO. 5, SEPTEMBER

2 758 J. A. FIXSEN, P. L. S. LI Fig. 1 Radiograph of a subluxed hip showing the typical double-diameter acetabulum. osteotomy was required, one innominate (Salter) procedure 7 and two Pemberton pericapsular acetabuloplasties. 8 One patient had a femoral osteotomy followed by a Salter operation at an interval of six weeks. In general, a Salter osteotomy was performed when there was significant anterosuperior acetabular deficiency and a Pemberton acetabuloplasty when the socket was misshapen with a double diameter. 9,10 All patients were immobilised in a hip spica for eight weeks. Later procedures. Four patients required one further operation and the last child (case 10) had three more procedures because of redisplacement. Four of the six children who had previously had a femoral osteotomy alone, required a later operation to augment the acetabulum. Two younger children (cases 2 and 3) had an innominate and a Pemberton pericapsular osteotomy, respectively, around the age of six years. Two older children (cases 5 and 9) required a Wainwright shelf acetabuloplasty at the age of eight and 12 years, respectively. The last child (case 10) was treated initially by open reduction and Salter osteotomy. Seven months later, her hip subluxed posteriorly and a repeat open reduction was performed. Six weeks after this, the hip subluxed again posterolaterally and re-exploration confirmed that the acetabulum was poorly developed anteriorly as well as posteriorly. The hip was reduced and stability was only obtained by fixation with a Kirschner wire. A varus femoral osteotomy was later performed to compensate for excessive valgus and a persistent tendency to lateral subluxation. She has not required further surgery, although her radiological outcome has not been good. Results The mean age at the time of first operation was 6.3 years (4.8 to 9.5) and the mean follow-up 8.75 years (7 to 10.5). All patients, except one, were reviewed at maturity (age 15 years or more). One patient (case 6) was 12.5 years at her latest review and is currently doing well. The results at follow-up are shown in Table II. None of the patients had inequality of limb-length great- Table I. Details of the ten children with subluxation of the hip and their operations Age at first Primary Case Gender Side operation operations* Later operations* 1 F R 7 OR + FO - 2 F R 5.5 OR + FO Salter 3 F L 5.5 OR + FO(FS) Pemberton 4 F L 9.5 OR + Pemberton - 5 M R 7 OR + FO(FS) Wainwright 6 F R 5.5 OR + Pemberton - 7 F L 4.75 OR + FO - 8 F R 6 OR + FO + Salter - 9 F R 7 OR + FO Wainwright 10 F L 5.25 OR + Salter Repeat OR(x2), FO * OR, open reduction; FO, femoral osteotomy; FS, femoral shortening Table II. Long-term results for the ten children after surgery for subluxation of the hip Duration of Age at last Leg-length Kalamchi follow-up review Trendelenburg discrepancy Ponseti Severin and MacEwen Case (yr) (yr) test (cm) grade grade grade Delayed THE JOURNAL OF BONE AND JOINT SURGERY

3 THE TREATMENT OF SUBLUXATION OF THE HIP IN CHILDREN OVER THE AGE OF FOUR YEARS 759 Table III. Clinical outcome according to Ponseti 11 Grade Description 1 Asymptomatic 2 Slight hip pain after excessive walking 3 Limp, free movement and no pain 4 Limp and limitation of movement, no pain 5 Limp and pain 6 Limp, limitation of movement and pain Table IV. Radiological outcome according to Severin 12 Grade Radiological features 1 Normal 2 Moderate deformity of femoral head, neck or acetabulum 3 Dysplastic but not subluxed 4 Subluxed 5 Head articulates with secondary acetabulum in upper part of true acetabulum 6 Dislocated 7 Arthritic changes er than 2 cm. One patient (case 10), had a positive Trendelenburg test, and one, a delayed positive test (case 1). The clinical outcome according to Ponseti s criteria 11 was good in all ten children (Table III). The Severin radiological grade 12 was 3 or more in six hips and 4 or more in three hips (Table IV). Avascular necrosis assessed by the method of Kalamchi and MacEwen 13 was grade 2 or more in four hips; two of these had total involvement of the head leading to gross deformity (Fig. 2). Discussion The aim of treatment in late subluxation, as in established dislocation, is to achieve stable reduction and satisfactory subsequent development of the hip. In subluxation presenting over the age of four years, the acetabulum is distorted and has a double diameter (Fig. 1). The femoral head is also abnormal. A true, concentric reduction is therefore impossible to achieve. A stable reduction, with maintenance of good hip movement, should allow remodelling and improvement with time. To our knowledge, there has been no previous study of this particular type of late subluxation, although Klisic, Jankovic and Basara, 14 with a large experience of late dislocation of the hip, suggest that open reduction, acetabuloplasty and femoral shortening produce the most satisfactory results. The problems encountered in the management of the first patient in our series (case 10) highlighted that, although Fig. 2a Fig. 2b Case 3. Radiographs showing open reduction and varus derotational osteotomy with shortening at the age of five years (a), a Pemberton pericapsular acetabuloplasty after six months resulting in the desired reduction of acetabular volume (b), and at maturity, severe avascular necrosis with gross deformity of the femoral head, a short stunted femoral neck and relative trochanteric overgrowth (c). Fig. 2c VOL. 80-B, NO. 5, SEPTEMBER 1998

4 760 J. A. FIXSEN, P. L. S. LI Fig. 3a Fig. 3b Fig. 3c Case 2. Radiographs showing a typical subluxed right hip with a double-diameter acetabulum (a), after open reduction and varus derotational osteotomy (b) after innominate osteotomy as a second stage eight months later which gave satisfactory anterolateral cover (c) and at maturity with an excellent clinical result but a dysplastic acetabulum (Severin grade 3) (d). Fig. 3d radiologically the acetabulum appeared to be the major problem, failure to assess and treat the considerable femoral anteversion led to posterior subluxation after a Salter osteotomy. This complication of the Salter procedure has been previously described as due to the improvement in anterosuperior cover being achieved at the expense of posterior stability. 15 Femoral anteversion is clinically not apparent in these patients when the hip is in the subluxed position, but becomes so when the femoral head is reduced at open reduction. Eight of the ten hips ultimately required a femoral varus rotation osteotomy for marked femoral anteversion. In six hips, varus rotation osteotomy alone was sufficient to provide stability without tension and only two required concomitant shortening, unlike the late presenting, high dislocation, in which it is almost invariably necessary. The inability of the acetabulum to respond satisfactorily to stable reduction of the femoral head was shown by four children who later required acetabular surgery after femoral osteotomy as the primary operation. This supports the opinion of previous reports of the ability of the acetabulum to respond to stable reduction and femoral osteotomy Two patients, in whom the major deformity was a misshapen, double-diameter acetabulum without excessive anteversion, were successfully treated by open reduction and Pemberton pericapsular acetabuloplasty. These patients have not required further operation. The clinical outcome was good, but the radiological scores were not as satisfactory. Three hips were Severin grade 4 or more (subluxed). 12 Three remained dysplastic (Fig. 3). Four hips showed avascular necrosis of Kalamchi and MacEwen grade 2 or more. 13 Lack of concordance between clinical function and radiological outcome has been previously documented and it has been suggested that the best index of long-term outcome is the Severin grade. 19 It is likely that some of these hips will develop symptoms in early adult life. It could be argued that those patients with a hip of Severin grade 4 or more had not benefited from treatment. All, however, had presented with troublesome symptoms and a persistent limp. Their clinical outcome and function, according to the Ponseti criteria, 11 were satisfactory at final review, suggesting that some benefit had been gained from the surgery. The value of this type of retrospective review is in the lessons that have been learned, particularly from the first patient in this series (case 10) who had the poorest result despite repeated surgery. At presentation, the plain radiographs suggested that the major problem was in the acetabulum, which at exploration was deformed and had a THE JOURNAL OF BONE AND JOINT SURGERY

5 THE TREATMENT OF SUBLUXATION OF THE HIP IN CHILDREN OVER THE AGE OF FOUR YEARS 761 double diameter. Failure to consider the excessive anteversion of the femur, which is not demonstrable clinically, led to the problems in case 10 and the necessity for a femoral osteotomy either as a primary or secondary procedure in eight out of the ten hips. We now advise open reduction through a wide exposure allowing full assessment of the acetabular and femoral components of the deformity. Most patients are likely to require both acetabular reconstruction and a femoral osteotomy, with or without shortening, so that the final reduction is not under tension. It would seem appropriate to undertake this as a one-stage rather than a two-stage procedure. Four patients required later acetabular surgery. This underlines the contention that over the age of four years, the ability of the acetabulum to respond to reduction of the femoral head is less certain and that it is advisable to include an acetabular procedure in the primary operation, however stable the hip appears after open reduction and femoral osteotomy, with or without shortening No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. References 1. Klisic PJ. Congenital dislocation of the hip: a misleading term. J Bone Joint Surg [Br] 1989;71-B: Ortolani M. Un segno poco noto e sua importanza per la diagnosi precoce di prelussazione conenita dell anca. Pediatria 1937;45: Barlow TG. Early diagnosis and treatment of congenital dislocation of the hip. J Bone Joint Surg [Br] 1962;44-B: Catterall A. Editorial. What is congenital dislocation of the hip? J Bone Joint Surg [Br] 1984;66-B: Graf R. Fundamentals of sonographic diagnosis of infant hip dysplasia. J Pediatr Orthop 1984;4: Catterall A. Editorial. The early diagnosis of congenital dislocation of the hip. J Bone Joint Surg [Br] 1994;76-B: Salter RB. Innominate osteotomy in the treatment of congenital dislocation and subluxation of the hip. J Bone Joint Surg [Br] 1961; 43-B: Pemberton PA. Pericapsular osteotomy of the ilium for treatment of congenital subluxation and dislocation of the hip. J Bone Joint Surg [Am] 1965;47-A: Catterall A. Congenital dislocation of the hip: the indications and technique of open reduction. Acta Orthop Belg 1990;56: Benson MKD, Macnicol MF. Congenital dislocation of the hip. In: Benson MKD, Fixsen JA, Macnicol MF, eds. Children s orthopaedics and fractures. Edinburgh: Churchill Livingstone, 1994: Ponseti IV. Causes of failure in the treatment of congenital dislocation of the hip. J Bone Joint Surg 1944;26: Severin E. Contribution to knowledge of congenital dislocation of hip joint: late results of closed reduction and arthrographic studies of recent cases. Acta Chir Scand 1941 [Suppl 63];84; Kalamchi A, MacEwen GD. Avascular necrosis following treatment of congenital dislocation of the hip. J Bone Joint Surg [Am] 1980; 62-A: Klisic P, Jankovic L, Basara V. Long-term results of combined operative reduction of the hip in older children. J Pediatr Orthop 1988;8: Fixsen JA. Anterior and posterior subluxation of the hip following innominate osteotomy. J Bone Joint Surg [Br] 1987;69-B: Harris NH, Lloyd-Roberts GC, Gallien R. Acetabular development in congenital dislocation of the hip: with special reference to the indications for acetabuloplasty and pelvic or femoral realignment osteotomy. J Bone Joint Surg [Br] 1975;57-B: Kasser JR, Bowen JR, MacEwen GD. Varus derotation osteotomy in the treatment of persistent dysplasia in congenital dislocation of the hip. J Bone Joint Surg [Am] 1985;67-A: Schoenecker PL, Anderson DJ, Capelli AM. The acetabular response to proximal femoral varus rotational osteotomy: results after failure of post-reduction abduction splinting in patients who had congenital dislocation of the hip. J Bone Joint Surg [Am] 1995; 77-A: Fairbank JC, Howell P, Nockler I, Lloyd-Roberts GC. Relationship of pain to the radiological anatomy of the hip joint in adults treated for congenital dislocation of the hip as infants: a long-term follow-up of patients treated by three methods. J Pediatr Orthop 1986;6: VOL. 80-B, NO. 5, SEPTEMBER 1998