Cementless Hip Arthroplasty in Diastrophic Dysplasia J. I. P e l t o n e n , M D , * V. H o i k k a , M D , * M . P o u s s a , M D , * T. P a a v i l a i n e n , M D , * a n d I. K a i t i l a , M D t

Abstract: Diastrophic dysplasia results in severe disproportionate growth failure, generalized joint dysplasia, and early osteoarthrosis of the hips. A total hip arthroplasty is often necessary in patients afflicted with diastrophic dysplasia by time they reach early middle age. During 1983-1988, total hip arthroplasties were performed on six women and four men (15 hips) with diastrophic dysplasia at the Orthopaedic Hospital of the Invalid Foundation. The mean age of the patients at the time of operation was 37 years and the mean height was 133 cm. A Lord endoprosthesis was used in nine hips and a Biomet endoprosthesis in six. Cementless fixation was used in all cases. Autogenous bone grafting to the acetabulum was performed in six hips. Simultaneous corrective osteotomy of the proximal femur and transposition of the greater trochanter was performed in three cases. Soft tissue release and tenotomies were performed in l0 hips. The average follow-up period was 5 years. Overall clinical results were good, with marked relief of pain and improvement of hip joint mobility. Aseptic loosening of the acetabular component was noted in two hips. As for complications, two femoral nerve paresis and two perioperative fractures of the proximal femur occurred, which all healed. Key words: coxarthrosis, diastrophic dysplasia, osteochondrodysplasia, total hip arthroplasty.

Diastrophic dysplasia (DD) is a rare autosomal recessive type of skeletal dysplasia producing a shortlimb dwarfism, recognizable at birth. The disease was first delineated by Lamy and Maroteaux in 1960. 6 Although rare in most countries, where an approximate total of 250 cases of DD have been diagnosed, the disease seems to be more c o m m o n in Finland where at least 160 cases have been diagnosed in that country alone. ~3, ~4 A short stature, atypical club feet, flexion limitation of the finger joints, scoliosis, and contractures of the joints are typical clinical features for a diastrophic

patient. 23 The clinical problems related to the contractures of the hips and knees become manifest w h e n the child begins to stand and walk. Flexion contracture of the hip joint is due to the shortening of the flexors and to the deformity of the proximal femoral epiphysis. 2,15 Flexion contracture of the knees may be a secondary consequence to the hip joint contractures. Because of the dysplasia and abnormal articular cartilage of the hip joint in DD, a painful secondary arthrosis with marked restriction of joint m o v e m e n t develops in early middle-age. 1° Reports of performing a total hip arthroplasty (THA) in DD patients are few. ~ To our knowledge studies concerning cementless THA in this disease have not been reported. The purpose of this study was to ascertain the operative technical problems and the clinical and radiographical results cementless of THA in patients with DD.

From the *Orthopaedic Hospital of the Invalid Foundation, Helsinki, Finland and the -~Department of Medical Genetics, University of Helsinki, Finland.

Supported by a grant from the Sigrid Juselius Foundation, Finland. Reprint requests: Jari I. Peltonen, MD, University of Helsinki, Children's Hospital, Stenb~ckinketer 77, SF-00290 Helsinki, Finland.

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Materials and Methods From 1983 to I988 THAs were performed on six w o m e n and four m e n (15 hips) with DD in the Orthopaedic Hospital of the Invalid Foundation in Helsinki. Indications for the operation were pain and marked restriction of joint mobility. In all cases flexion contracture of both hips of 150-40 ° was clinically observed. Most of the patients had flexion contractures and valgus deformities of the knees as well as other deformities of the joints and vertebral colu m n (Fig. l, Table 1). This diagnosis was based on

Fig. 1. A 37-year-old woman with the typical features of

diastrophic dysplasia: short stature (height, 124 cm); contractures of both hips, knees and, ankle joints; club feet; and toe deformities.

Table 1. Major Deformities of the Lower Limbs and

Vertebral Column of the Patients Patients Knees Valgus deformity Flexion contracture Instability Patella laterally luxated Feet and Ankles Equinus contracture Forefoot deformity Vertebral Column Scoliosis, thoracolumbar Lumbar Spinal stenosis

5 9 2 3 6 8 2 i 1

the typical clinical features and radiographical findings confirmed by a clinical genetist. The mean age of the patients at the time of operation was 37 years (range, 3 3 - 4 3 years), m e a n height was 133 cm (range, 124-152 cm), and m e a n weight was 39 kg (range, 3 1 - 5 0 kg). Two-stage bilateral THA was performed on five patients. In one case the operation was a revision of the earlier endoprosthesis fixed by cement (patient 9). The operations preceding the cementless THA are presented in Table 2. In two siblings an earlier THA had been performed by cement fixation (patients 9 and 10). Aseptic loosening of these endoprostheses was noted 2 - 3 years after the surgery, and marked ectopic ossification around the hips had developed. The operation was performed with the patient on his or her side. The lateral approach according to Hardinge 8 was used in I2 hips and the Moore posterior approach in 3 hips. If transposition of the greater trochanter was planned, the Moores posterior approach was chosen because it would better preserve the gluteus medius insertion. The diameter of the isthmus of the operated femurs averaged 1.3 cm w h e n measured from the plain radiographs. Marked anterior bowing was noted in eight femurs. A Lord madreporic total endoprosthesis was used in nine hips, and a Biomet endoprosthesis (Biomet, Warsaw, IN) with a straight, proximally porous-coated stem of titanium alloy and threaded acetabular c o m p o n e n t was used in six. Simultaneous corrective osteotomies were performed according to the m e t h o d of Paavilainen et al. 19 in three cases due to the deformity of the proximal femur. In one case a shortening osteotomy of the proximal femoral metaphysis was performed. In another patient a shortening osteotomy and transposition of the greater trochanter were carried out o n both sides (Fig. 2). In the third patient the femur

Cementless THA in Diastrophic Dysplasia

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T a b l e 2. P a t i e n t D a t a Earlier Hip Operations Patient No.

Sex

Age

(right/left, year of operation)

1

m

41

2 3

m m

39 33

4

f

33

5 6 7

f f f

34 36 37

8

m

36

9

f

34

THA, right, i978

10

f

43

THA, right, 1977 FO, left, I978

Mean

--

bilateral, FO, 1960 --bilateral, FO, 1965 ----

Endoprosthesis Used In This Study (right/left)

F o l l o w - u p Time

(years)

Lord, left Lord, left Biomet, right Biomet, left Lord, right Lord, left Biomet, left Lord, right Lord, right Lord, left Biomet, left Lord, right Lord, left Biomet, right* Biomet, left

8.7 6.4 3.6 3.6 6.7 5.6 3.5 7.0 6.5 3.9 3.9 3.9 5.6 2.9 3.7

Lord, left

3.6 5.0

37

FO, intertrochanteric femoral osteotomy; THA, earlier total hip arthroplasty with cement fixation. * Re-arthroplasty.

w a s t o o n a r r o w e v e n for t h e s m a l l e s t s t e m available. Therefore, t h e p r o x i m a l f e m u r w a s split l o n g i t u d i nally, a n d a s h o r t e n i n g o s t e o t o m y a n d t r a n s p o s i t i o n of t h e g r e a t e r t r o c h a n t e r w a s t h e n p e r f o r m e d . A u t o g e n o u s c a n c e l l o u s b o n e grafting w a s perf o r m e d in six h i p s to reinforce t h e a c e t a b u l a r m e d i a l wall. The r o o f of t h e a c e t a b u l u m w a s r e c o n s t r u c t e d in t h r e e h i p s u s i n g a n a u t o g e n o u s b o n e graft f r o m the f e m o r a l h e a d (Fig. 2A,B). Soft tissue release a n d t e n o t o m i e s of t h e h i p a d d u c t o r s a n d flexors w e r e perf o r m e d in 10 hips. P r o p h y l a c t i c a n t i b i o t i c t h e r a p y (flucloxacillin or c l i n d a m y c i n - h y d r o c h l o r i d e ) w a s g i v e n 2 h o u r s before t h e o p e r a t i o n a n d c o n t i n u e d for 48 h o u r s thereafter. T h r o m b o e m b o l i c p r o p h y l a x i s s u b c u t a n e o u s di-

hydroergotamine with heparin was administered on t h e d a y of the o p e r a t i o n a n d 1 w e e k after surgery. B e c a u s e of t h e m a r k e d p r e o p e r a t i v e j o i n t c o n tractures, after t h e s u r g e r y t h e p a t i e n t s laid in a p r o n e p o s i t i o n d a i l y for a c o u p l e of h o u r s to d i m i n i s h t h e tightness of t h e h i p flexors. Half w e i g h t b e a r i n g w a s a l l o w e d after surgery, a n d t h e p a t i e n t s u s e d c r u t c h e s for 2 - 3 m o n t h s . I n cases w h e r e a s i m u l t a n e o u s f e m oral o s t e o t o m y w a s p e r f o r m e d , p a r t i a l w e i g h t b e a r ing w a s c o n t i n u e d for u p to 4 - 5 m o n t h s . P h y s i o t h e r a p y of t h e h i p j o i n t s a n d w a l k i n g exercises w e r e c o n t i n u e d for 2 - 4 m o n t h s after surgery. The clinical e v a l u a t i o n of t h e p a i n a n d r a n g e of m o t i o n w a s p e r f o r m e d a c c o r d i n g to t h e scoring scale of d ' A u b i g n e a n d Postel as m o d i f i e d b y C h a r n l e y . 4 The r a d i o -

Fig. 2. The same patient as in Figure 1. (A) Preoperative radiograph. Note severe secondary arthrosis with subluxation of both hips. (Figure continues)

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Fig. 2 (Continued) (B) Radiograph taken 2 months after THA of the right hip. Osteotomy of the proximal femur with transposition of the greater trochanter has been performed. The acetabular roof has been reconstructed by an autogenous bone graft taken from the femoral head. (C) Radiograph taken 3 years later. The left hip has been replaced by a Biomet screw ring and a Lord femoral component. The same reconstructive procedures as on the right hip have been performed.

graphical evaluation was based on the rating system described by J o h n s t o n et al. 12

postoperative blood loss varied from 500 to 4, i 00 mL (mean, 1,210 mE). The average follow-up period was 5 years (range, 2 . 9 - 8 . 7 years).

Results Clinical Evaluation Perioperatively, a good primary stability of the c o m p o n e n t s was achieved in every case. The average duration of the operation was 147 minutes (range, 9 0 - 2 5 0 minutes). The total a m o u n t of peri- and

Before surgery all of the hips were extremely painful with restricted m o v e m e n t (Tables 3 and 4). The relief of pain after the surgery was evident (Table 3).

Fig. 3. (A) Preoperative radiograph of a 43-year-old woman. The right hip was operated on 10 years earlier using a Lagrange Letournel total endoprosthesis with cement fixation. Both components are loose and a marked ectopic ossification around the joint is evident. The left hip is severely arthrotic. (B) Radiograph taken 1 year after the THA of the left hip by a Lord endoprosthesis.

C e m e n t l e s s THA in

1 2 3 4 5 6

Preoperative (No. of Hips)

Postoperative* (No. of Hips)

4 7 4 ----

--2 2 1 11

1, severe and spontaneous; 6, no pain. * At the final follow-up examination.

E l e v e n h i p s a p p e a r e d t o t a l l y p a i n - f r e e at t h e final f o l l o w - u p e x a m i n a t i o n . I n t w o h i p s (patients 9 a n d 10) t h e p a i n w a s p r o g r e s s i v e a n d l o o s e n i n g o f t h e e n d o p r o s t h e s i s w a s clinically s u s p e c t e d . These h i p s also h a d r a d i o g r a p h i c a l signs of l o o s e n i n g of t h e cup. All p a t i e n t s c o u l d w a l k w i t h o u t s u p p o r t . H o w e v e r , n i n e p a t i e n t s h a d a l i m p t h a t w a s severe in t h r e e cases, m o d e r a t e in four, a n d slight in t w o . A positive,

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Table 4. Pre- and Postoperative Evaluation of the Range of Motion Charnley's Scoring Scale

T a b l e 3. Pre- and Postoperative Scoring of the Pain According to Charnley's 6-point Scale Score

Diastrophic Dysplasia

Preoperative Score

No. of Hips

Postoperative 1.5-3 Years* Final Check (No. of hips) (No. of hips)

1 2 3 4 5

5 3 5 2 --

--3 11 l

1 1 8 5 --

6

- -

- -

- -

* Control 1.5-3 years after surgery.

b i l a t e r a l T r e n d e l e n b u r g sign w a s n o t e d in j u s t o n e p a t i e n t . P o s t o p e r a t i v e r e s t r i c t i o n in w a l k i n g a n d o t h e r d a i l y activities w e r e , for t h e m o s t part, d u e to o t h e r j o i n t p r o b l e m s . T h e p a t i e n t s ' o v e r a l l assessm e n t of t h e o p e r a t i o n w a s e x c e l l e n t o r g o o d i n e i g h t cases a n d fair in t w o cases ( p a t i e n t s 9 a n d 10). The pre- a n d p o s t o p e r a t i v e r a n g e o f m o t i o n o f t h e h i p s are p r e s e n t e d in Table 4. I m p r o v e m e n t in h i p

Fig. 4. Postoperative radiograph of a 34-year-old woman with a Biomet THA at the 3.7-year follow-up examination. Clear migration of the cup and prosthesis-bone radiolucency is seen. The position of the stem has not been changed, but the bone density is increased in the middle and distal part (arrows). Loss of bone is seen in the proximal femur. (A) A-p. (B) Lateral projection of the hip.

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The Journal of Arthroplasty Vol. 7 Supplement 1992 T a b l e 5A. R a d i o g r a p h i c a l C h a n g e s of t h e A c e t a b u l u m : M i g r a t i o n of C o m p o n e n t *

T a b l e 5C. R a d i o g r a p h i c a l C h a n g e s of t h e Acetabulum: Position of Component*

Hips mm

Superior

Medial

1-2 2-3 3-4 4-8

3 --2

2 1 -I

Inclination:

3 5 - 5 0 ° (mean, 41 ° )

Version of Cup:

a n t e v e r s i o n 5 - 2 5 ° (mean, 15 °) neutral position in t w o cases

* In all 15 hips.

* I n 7 o f 15 hips.

Table 6A. Radiographical Changes of the Femur: S u b s i d e n c e of S t e m *

joint mobility was more evident at earlier (1.5-3 years) follow-up examinations w h e n compared to the final result (mean, 5 years). There was a clear tendency to restrict movements in the long term.

mm

No. of Hips

1-2 2-3 3-4

4 0 1

* I n 5 of 15 hips.

Radiographical Evaluation Pre- and postoperative radiographical findings are shown in Figures 2 - 4 . In the acetabulum, slight migration of the c o m p o n e n t was noted in five hips, and a migration of 4 m m or more was noted in two hips. One of these (patient 9) had continuous prosthesisbone radiolucency of 4 m m of the cup (Tables 5A-C, Fig. 4). All of the bone grafts in the acetabulum were incorporated and no resorption was noted. There was no migration to varus or valgus in the femoral side. Endosteal cavitation was not found. Osteotomies of the proximal femur and greater trochanter were all healed. Slight ectopic ossification (Brooker grade II) in the cranial part of the joint was noted in four hips. Tables 6 A - E show the radiographical changes of the femurs. Although slight subsidence, local prosthesis bone radiolucency, and resorption of the medial part of the neck were found, these changes were not considered signs of true loosening of the component.

T a b l e 6B. R a d i o g r a p h i c a l C h a n g e s of t h e F e m u r : Prosthesis-bone Radiolucency* mm

Zones

1-2

l, 8, 14 1, 14

2-3 * I n 4 o f 15 hips

T a b l e 6C. R a d i o g r a p h i c a l C h a n g e s of t h e F e m u r : R e s o r p t i o n of M e d i a l P a r t o f N e c k * Loss Height

Thickness

1-3 mm

1-2 m m

* I n 7 o f i5 hips.

T a b l e 6D. R a d i o g r a p h i c a l C h a n g e s of t h e F e m u r : R e s o r p t i o n or H y p e r t r o p h y of Shaft*

Complications In two patients lesion of the femoral nerve on the operated side was observed after surgery. In the first case, weakness of the quadriceps muscle

Zones

Resorption

Hypertrophy

--

2,3,4,6,11 * I n T o f 15 hips.

T a b l e 5B. R a d i o g r a p h i c a l C h a n g e s of t h e Acetabulum: Prosthesis-bone Radiolucency* T a b l e 6E. R a d i o g r a p h i c a l C h a n g e s of t h e F e m u r : Change in Density*

Zone No. mm

1

2

3

2 hips --

3 hips 1 hip

Loss

1-2 8 hips 2-3 -Continuous (4 ram) in one case * I n 5 of 15 hips.

Patchy Uniform * I n 6 o f i5 hips.

Zones

1, 7, 14 1,7

Cementless THA in Diastrophic Dysplasia

strength was immediately evident, but spontaneous healing occurred completely within 2 months. In another patient a total paralysis of the femoral nerve was noted. At the second operation, 6 months after THA, the ruptured nerve was reconstructed using a 6 cm long free sural nerve graft. Recovery of the quadriceps function gradually occurred, and 1.5 years after the second operation only a slight weakness of the muscle strength was observed. In two cases a preoperative fracture of the proximal femur o c c u r r e d - - b o t h healed conservatively without affecting the final result of the operation. The total complication rate in this series was 25%. Loosening of the acetabular component in the two hips was both clinically and radiographically evident (patients 9 and 10). One was revised and the cup was changed to a Biomet porous-coated spherical press-fit cup. The other patient is awaiting revision.

Discussion Diastrophic dysplasia results in a severe physical handicap and limitation of walking ability beginning in early childhood. Although diastrophic patients have problems related to the vertebral column and the joints of the lower extremities, 2'~5 the severe progression of pain and contracture of the hips are the main reasons w h y their walking is restricted. 23 Because of the multiple bone and joint deformities affecting the daily activities of these patients, the clinical evaluation had to be simplified. Although relief of pain was most evident in this study, a tendency to gradually lose hip joint mobility after surgery was observed in the long term. The genetic disorder of DD has been recently described. 9 Although the basic biochemical abnormality of DD is u n k n o w n , ~1 it is likely that the structure of the bone itself is sufficient for cementless fixation of the endoprosthesis. In this series the primary stability of the fixation of the components was good. The low weight of the patients and their minor functional activity, because of multiple joint deformities, are probably beneficial for the fixation of the endoprosthesis to the bone. On the other hand, their abnormal gait may cause unfavorable loading effects to the hip joint. It has been shown that cementless THA is a suitable alternative in treating primary or secondary hip arthrosis. 3'17 The results of cementless THA after at least a 5-year follow-up period are good and the rate of aseptic loosening is low. ~8 On the other hand, Shaw et al. 2° reported a very high percentage of loosening of the threaded acetabular components, especially in revision hip arthroplasties. According to

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Engh et al. 7 the rate of loosening of the threaded acetabular cups is over 20% after a 4-year follow-up period. In this series two acetabular components were definitely loose after 3 . 6 - 3 . 7 years of follow-up visits. In these same patients, w h o are siblings, the earlier cemented hip endoprostheses also had loosened 2 - 3 years after surgery. The remainder of the patients did not have any clinical symptoms of c o m p o n e n t loosening, although slight radiographical changes were found on both the acetabular and femoral side. Because of the relatively high rate of loosening of the threaded acetabular components, 7 a cementless press-fit, porous-coated spherical cup is apparently preferable, which is also our present policy. The changes in the femur, such as cortical hypertrophy in the distal part and loss of bone in the proximal part, are probably due to problems with the fit of the femur-prosthesis and stress concentration to the distal femur. It is obvious that more custom-made femoral components are needed to fit the shape of the diastrophic femurs, which are often relatively wide proximally and rapidly narrowing distally with anterior bowing of the shaft. The alternative methods of osteotomies combined with THA in severe hip dysplasia have recently been described. 19'21 In this study the same solutions for reconstruction of the joint were used. The majority of the hips could be operated on without additional osteotomies of the femur. In the three cases with severe flexion contracture and tightness of the joint, a shortening osteotomy combined with the greater trochanter transfer and tenotomies gave a good functional result. The soft tissue release was performed to facilitate the reduction of the endoprosthesis and to improve the postoperative mobility of the joint. Complications included two femoral nerve lesions and two intraoperative fractures of the proximal femur. One of these complications, neuretmesis of the femoral nerve, was considered to be serious. The risk for femoral nerve damage is increased in cases where the rectus t e n d o n release is performed. The other complications did not affect the final result of the operation. The reasons for complications in this series were: (I) severe contractures and scar tissue after the earlier hip operations; (2) deformed and subluxated joints; and (3) short dimensions in the operated area. The complication rate is comparable to those reported in other studies of THA of severely deformed joints. 5,19,24 Total hip arthroplasty is a technically demanding procedure w h e n performed on patients with DD. However, THA is the only operation by which the relief of pain and an increase in the range of motion of the severely arthritic joint can be achieved. A1-

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t h o u g h t h e p a t i e n t s w e r e y o u n g at t h e t i m e of o p e r a tion, w e c o n s i d e r T H A to b e i n d i c a t e d in this disease.

References 1. Bell RS, Rosenthal RE: Bilateral total hip replacement in a diastrophic dwarf. Orthopedics 3:534, 1980 2. Bethem D, Winter RB, Lutter L: Disorders of the spine in diastrophic dwarfism. J Bone Joint Surg 62A:529, 1980 3. Callaghan J J, Dysart SH, Savory CG: The uncemented porous-coated anatomic total hip prosthesis. J Bone Joint Surg 70A:337, 1988 4. Charnley J: The long-term results of low-friction arthroplasty of the hip performed as a primary intervention. J Bone Joint Surg 54B:61, 1972 5. Dunn HK, Hess WE: Total hip reconstruction in chronically dislocated hips. J Bone Joint Surg 58A:838, 1976 6. Elima K, Kaitila I, Mikonoja L e t al: Exclusion of the COL2A1 gene as the mutation site in diastrophic dysplasia. J Med Genet 26:314, 1989 7. Engh CA, Griffin WL, Marx CL: Cementless acetabular components. J Bone Joint Surg 72B:53, 1990 8. Hardinge K: The direct lateral approach to the hip. J Bone Joint Surg 64B:17, 1982 9. H/istbacka J, Kaitila I, Sistonen P, de la Chapelle A: Diastrophic dysplasia gene maps to the distal long arm chromosome 5. Proc Natl Acad Sci U S A 87:8056, 1990 10. Hollister DW, Lachman RS: Diastrophic dwarfism. Clin Orthop 114:61, 1976 11. Horton WA, Rimoin DL, Hollister DW, Silberberg R: Diastrophic dwarfism: a histochemical and ultrastructural study of the endochondral growth plate. Pediatr Res 13:904, 1979

12. Johnston RC, Fitzgerald Jr RH, Harris W H e t al: Clinical and radiographic evaluation of total hip replacement: a standard system of terminology for reporting results. J Bone Joint Surg 72A:161, 1990 13. Kaitila I: Diastrophic dysplasia, p. 610. In: Population structure and genetic disorders. Academic Press, London, 1980 14. Kaitila I, Marttinen E, Merikanto J et al: Clinical expression and course of diastrophic dysplasia. Am J Med Genet 34:141, 1989 15. Kopits SE: Orthopedic complications of dwarfism. Clin Orthop 114:153, 1976 16. Lamy M, Maroteaux P: Le nanisme diastrophique. Presse Med 68:1977, 1960 17. Lord G, Bancel P: The madreporic cementless total hip arthroplasty: new experimental data and a seven-year clinical follow-up study. Clin Orthop 176:67, 1983 18. Lord G, Marotte J-H, Blanchard JP et al: Cementless madreporic and polarised total hip prostheses: a Tenyear review of 2,688 cases. French J Orthop Surg 2: 82, 1988 19. Paavilainen T, Hoikka V, Solonen K-A: Cementless total hip replacement of severely dysplastic or dislocated hips. J Bone Joint Surg 72B:205, 1990 20. Shaw JA, Bailey JH, Bruno A, Greet RB: Threaded acetabular components for primary and revision total hip arthroplasty. J Arthroplasty 5:201, 1990 21. Silber DA, Engh CA: Cementless total hip arthroplasty with femoral head bone grafting for hip dysplasia. J Arthroplasty 5:231, 1990 22. Stanescu V, Stanescu R, Maroteaux P: Pathogenic mechanisms in osteochondrodysplasias. J Bone Joint Surg 66A:817, 1984 23. Walker BA, Scott CI, Hall JG et al: Diastrophic dwarfism. Medicine 51:41, 1972 24. Woolson ST, Harris WH: Complex total hip replacement for dysplastic or hypoplastic hips using miniature or microminiature components. J Bone Joint Surg 65A:1099, 1983