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Operative Treatment

Arthrodiastasis of the Hip

Hosny, Gamal Ahmed MD*; El-Deeb, Khamis MD; Fadel, Mohamed MD; Laklouk, Mohamed MD

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Journal of Pediatric Orthopaedics: September 2011 - Volume 31 - Issue - p S229-S234
doi: 10.1097/BPO.0b013e318223b45a
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Treatment of Legg-Calvé-Perthes disease is a controversial issue.1 The results for treatment of patients with age of onset >8 years of age tend to be less favorable than the younger age. Greater involvement of the lateral pillar of the femoral head carries the risk of poor prognosis. Besides, marked restriction of hip motion precludes the application of osteotomies for management. Arthrodiastasis is a relatively new method of treatment. It does not change the anatomy of the joint. It provides unloading of the joint, which negates the harmful effect of the stresses on the articular surfaces, which may promote the sound healing of the areas of necrosis.1

Arthrodiastasis usually describes articulated distraction and often open surgery of the hip as a treatment of a variety of conditions such as avascular necrosis, osteoarthritis, and chondrolysis.2 The indications of arthrodiastasis had been extended to include cases with Legg-Calvé-Perthes disease where poor results were expected from other treatment modalities.3

However, soft tissue release was performed in most cases, in addition to articulated distraction. We have been applying this method since 1992, but we observed that some patients who had severe pain refused to mobilize the operated hip. In fact, this was static hip distraction. Moreover, we could not clarify from the literature the validity of soft tissue release or its long-term effect on sports activities. In this study, we reviewed the literature highlighting the indications, results, and complications of arthrodiastasis in Legg-Calvé-Perthes disease. Besides, we report our midterm results after application of nonarticulated arthrodiastasis without soft tissue release.


From 1995 till 2007, 33 cases with Legg-Calvé-Perthes disease were treated with nonarticulated joint distraction in our institution. Four cases were excluded due to inadequate follow-up data.

The inclusion criteria were as follows:

  1. Age above 8 years.
  2. Herring lateral pillar classification type B or C.
  3. Severe restriction of movement.
  4. Severe pain.
  5. One or more Catterall head at risk signs.4

The age of patients ranged from 8 to 14 years (4 cases were 12 y or older). There were 22 boys. All the cases were unilateral. Four patients had previous operations (Fig. 1).

A, An 8.5-year-old boy with Legg-Calvé-Perthes disease in the right hip treated by Salter osteotomy with resultant complete hip stiffness and severe pain. B, Immediate postoperative radiograph. C, Radiographs at the end of distraction. D, Radiograph after removal. E, Last follow-up x-ray (after 7 y) with spherical congruency.

The operative treatment included the application of an Ilizarov external fixator to the pelvis and the femur. Two or 3 Schanz screws of 5 mm or 6 mm in size were applied to the supra-acetabular area and fixed to 90 degrees arch. One and half rings were applied to the femur using 1.8 mm tensioned wires in addition to the Schanz screws. The frame was connected while the femur is abducted approximately 15 degrees. After 3 days, gradual distraction started at a rate of 1 mm per day till over correction of Shenton line by 5 to 10 mm. The patients were encouraged to walk with partial weight bearing using 2 elbow crutches immediately after the operation. We did not perform any soft tissue release for all patients. External fixation time ranged from 2.5 to 5 months. All the hips were graded as C Herring classification, except 5 cases that were graded as B. There were 13 group III hips and 16 group IV hips according to the Catterall classification.5 We have been able to apply Salter and Thompson classification to 24 cases, and 19 of them were B group.6

After fixator removal, the patients had daily physiotherapy with passive continuous and active-assisted movement, hydrotherapy with nonweight-bearing mobilization for 2 months and then progressive weight bearing and physiotherapy for 2 more months. The patients were assessed clinically and radiographically before the operation, after the operation, every 1 week till the end of distraction, then every 3 weeks till removal of the fixator, every 1 month for 6 months, and finally every 6 months. Clinically, the presence and degree of pain, range of motion, functional activity level, and satisfaction of the patient were recorded. Stulberg classification was applied to the patients who reached skeletal maturity at last follow-up.

Pain was graded as no pain; mild pain; intermittent pain, which developed after exercises; moderate pain, which developed after regular activities; and severe pain, which is constant pain deserving the regular use of pain killers. The joint space was measured before and after the operation. The sphericity of the femoral head was evaluated at follow-up by Mose concentric rings.7


The follow-up period ranged from 2.5 years to 11 years with an average of 7.5 years. Twenty-seven cases (93%) had improvement of the range of motion postoperatively. Preoperatively, all patients had constant pain, whereas at last follow-up 26 (86%) patients had no pain and 3 had an improvement.

Preoperatively, the average hip flexion was 40 degrees (range, 0 to 65 degrees), whereas at last follow-up it improved to 80 degrees (range, 0 to 120 degrees). All patients were satisfied with the results, except 1. The average joint space before surgery was 2.4 mm (range, 1 to 4 mm) and at the last follow-up it was 4.2 mm (range, 2 to 7 mm). At the last follow-up, 15 cases had spherical femoral head (deviation of <2 mm), 9 cases had deviation between 2 and 4 mm, and 5 cases with >4 mm deviation. Stulberg classification was applied to 21 cases who reached skeletal maturity at last follow-up of which 9 cases were type II, 7 cases were type III, 4 cases were type IV, and 1 case was type V. For the 4 cases of adolescent Legg-Calvés-Perthes disease (age >12 y), there were 1 case of type III, 2 cases of type IV, and 1 case of type V.


Pin track infection developed in 22 cases. Treatment with parenteral antibiotics and more frequent dressing was enough in all cases except 1, which required premature removal of the fixator after 2.5 months due to severe infection of the acetabular pins. There was marked knee stiffness in 2 cases on fixator removal, which resolved completely with physiotherapy. Chondrodiastasis occurred instead of arthrodiastasis in 1 patient aged 14 years with resultant lengthening of the femoral neck (Fig. 2). Hip subluxation developed in 1 case 1 year after fixator removal, but the femoral head was contained at last follow-up with almost full range of movement and no pain.

A, Legg-Calvé-Perthes disease of the right hip in a 14-year-old boy with complete stiffness, severe pain, and pelvic obliquity. B, Anteroposterior radiograph during distraction where chondrodiastasis occurred instead of arthrodiastasis. C, Follow-up radiograph showing lengthening of the femoral neck.


The aim of treatment of Legg-Calvé-Perthes disease is to prevent or minimize the development of deformities of the hip.8 Patients who are >8 years of age with type C lateral Pillar classification are expected to have poor outcome.9 With increasing age, the time available for the remodeling phase is limited, which may lead to rapid joint deterioration.10 A retrospective review was performed for 44 children (48 hips) with Catterall grade 2, 3, or 4 Legg-Calvé-Perthes disease with onset over 8 years or older followed to maturity. Patients were divided into 4 groups (a no-treatment group and 3 interventional groups). Patients were in the sclerosis or early fragmentation phase at the time of the operation. Overall for all treatment modalities, only 19% had a satisfactory Stulberg grade II outcome. Therefore, whatever the treatment, the outcome is poorer with increasing age.11

Combined innominate and femoral osteotomies are generally performed to better contain and to provide more coverage of the femoral head by the acetabulum. Radiographic outcome of 20 patients with a disease onset of over 8 years who had undergone combined femoral and Salter innominate osteotomies was recorded. The classification of the hips was 11 lateral pillar group B, 7 group B/C, and 2 group C. The patients were evaluated with a mean follow-up of 5 years and 5 months using the Stulberg radiographic classification. Among these 20 hips, 6 became Stulberg II (33%), and 9 were IV. The main complication among this group was joint stiffness in 1 case that was treated by adductor tenotomy and joint release.12

The first description of arthrodiastasis was given by Aldegheri in 1981.13 The aim of joint distraction is to neutralize muscle and weight-bearing forces, to prevent stress fractures of subchondral bone, and to promote creeping substitution.2,4 Experimental studies revealed the importance of continuous passive motion or intermittent active motion in the repair of articular cartilage defects. Hence, articulated distraction could improve healing of articular cartilage in the rabbit animal model.14 Soft tissue release in some or all the cases was performed during fixator application.3,4,15,16 We have been practicing articulated distraction in our center since 1992; however, the development of pain during passive or active hip motion leads to the refusal of most patients to mobilize the hip. Besides, we believe that the theoretical advantage of soft tissue release and joint motion during distraction has not been proven clinically. This theory was based on experimental studies regarding cartilage defects and not Legg-Calvé-Perthes disease. Hence, since 1995 we treated patients with nonarticulated distraction and without soft tissue release.

Maxwell et al17 in 2004 studied the impact of arthrodiastasis on the preservation of the femoral head in boys over the age of 8 years and girls over 7 years at the time of onset of symptoms of Legg-Calvé-Perthes disease. The patients were in the early fragmentation stage with minimal femoral head collapse (type A or B Herring Lateral Pillar classification at the time of the operation). After an average follow-up of 38.4 months, all the hips maintained their epiphyseal height except 2 (of the 15 operated cases). However, the follow-up was short and the sample included cases with minimal involvement, which may have the same results with other modalities of treatment.

Kucukkaya et al4 in 2000 reported 11 children with avascular necrosis of the femoral head (Legg-Calvé-Perthes disease in 8 of them) treated with articulated distraction. The patients with Legg-Calvé-Perthes disease were 3 and 4 Catterall classification,5 and B and C Lateral Pillar classification and all of them had >1 Catterall head at risk factors. Final follow-up results according to Stulberg were: spherical congruency 4 cases, aspherical congruency 3 cases, and 1 case of aspherical incongruency. They recommended this type of treatment for children older than 6 years who have Catterall risk factors, and poor results are expected from other treatment modalities.

Other investigators3 considered this type of treatment for children older than 9 years with severe form of the disease, with persistent severe pain, and with limited range of hip motion, which qualified them for salvage procedures. They reported good short-term clinical and radiologic results.

In our series, we had 9 cases with spherical congruency (Fig. 3), 11 cases with aspherical congruency, and 1 case with aspherical incongruency (of the 21 cases who reached skeletal maturity at last follow-up). Kucukkaya et al4 in 2000 had comparable results with the use of articulated distraction. The joint distraction without mobilization may carry the risk of hip joint stiffness. However, there was marked improvement of the range of motion from an average of 40 (range, 0 to 65 degrees) to 80 degrees (range, 0 to 120 degrees) at last follow-up. Other investigators reported improvement of flexion by a mean of 20 degrees after soft tissue release and articulated distraction.3

A, Legg-Calvé-Perthes disease of the left hip in a 10.5-year-old girl with type C lateral pillar classification. B, Anteroposterior radiograph during distraction. C, One-year postoperative radiograph. D, Last follow-up anteroposterior and lateral radiographs.

The rate of pin track infection was high (76%), with more prevalence in the acetabular side. This may carry the risk of potential infection if hip arthroplasty would be required in the future.18 Another unusual complication occurred in a 14-year-old boy with completely stiff hip preoperatively and mushroom-shaped head. Physeal distraction instead of joint distraction occurred in this case. To the best of our knowledge, there were no reports of physeal distraction of the upper femoral epiphysis before. We could not identify the reason behind this unusual phenomenon. Perhaps, the tension was conveyed to the femoral epiphysis instead of the hip joint due to marked intra-articular adhesions.

The technique of physeal distraction included the application of the half pins or k-wires to the epiphysis and to the diaphysis perpendicular to the axis of bone and gradual distraction by an external fixator. We did not apply any sort of fixation to the epiphysis of the femoral head. It seems that the tension was accumulating over time till sudden epiphyseal fracture or chondrodiastasis occurred. Slow, controlled, and symmetrical distraction of the epiphyseal plate without fracture or rupture signifies chondrodiastasis. In our case, there was no complaint of intense pain during distraction. Plain x-rays revealed 1.6 cm physeal distraction and lengthening of the femoral neck. At last follow-up after 8 years, there was no pain, no leg length inequality, but stiff hip was observed.19–22

The limitations of this study were that there was no control group as it was difficult to leave these patients with severe forms of the disease without treatment. Only 21 cases (72%) reached skeletal maturity at last follow-up. Besides, very few centers recommend arthrodiastasis.23 Comparing the results with other series was difficult due to the use of different classification systems and outcome measures (Table 1).4,19,24,25 The form of adductor tenotomy or illeopsoas release may be added to the. Arthrodiastasis can be articulated or nonarticulated. Soft tissue release in the form of adductor tenotomy or illeopsoas release may be added to the procedure. Articulated hip distraction with soft tissue release has few theoretical advantages over nonarticulated distraction, which has not been proven clinically.

Data of 5 Different Studies of Arthrodiastasis in Legg-Calvé-Perthes Disease

Arthrodiastasis has been used in the early stages of Legg-Calvé-Perthes disease (sclerotic or fragmentation phase) whatever the age of the patient. It has been applied as a definitive treatment or as a first step before surgical containment.26 It can also be applied as a salvage procedure in patients older than 8 years with severe types of Legg-Calvé-Perthes disease and with marked restriction of hip movement.

In late-onset severe cases, preliminary arthrodiastasis may reduce the pain and improve the range of motion before proceeding to surgical containment as varus osteotomy of the femur.

In conclusion, nonarticulated joint distraction without soft tissue release seems to yield similar results to articulated hip distraction in older patients with severe forms of Legg-Calvé-Perthes disease.


1. Herring JA. The treatment of Legg-Calvé-Perthes disease: a critical review of the literature J Bone Joint Surg Am.. 1994;76:448–458
2. Aldegheri R, Trivella G, Saleh M. Articulated distraction of the hip: conservative surgery for arthritis in young patients Clin Orthop Relat Res.. 1994;301:94–101
3. Segev E, Ezra E, Wientroub S, et al. Treatment of severe late onset Perthes' disease with soft tissue release and articulated hip distraction: early results J Pediatr Orthop B.. 2004;13:158–165
4. Kucukkaya M, Kabukcuoglu Y, Ozturk I, et al. Avascular necrosis of the femoral head in childhood: the results of treatment with articulated distraction method J Pediatr Orthop.. 2000;20:722–728
5. Catterall A. The natural history of Perthes' disease J Bone Joint Surg Br.. 1971;53:37–53
6. Salter RB, Thompson GH. Legg-Calvé-Perthes disease: the prognostic significance of the subchondral fracture and a two-group classification of the femoral head involvement J Bone Joint Surg Am.. 1984;66:479–489
7. Mose K. Methods of measuring in Legg-Calvé-Perthes disease with special regard to the prognosis Clin Orthop Relat Res.. 1980;150:103–109
8. Stulberg SD, Cooperman DR, Wallensten R. The natural history of Legg-Calvé-Perthes disease J Bone Joint Surg Am.. 1981;63:1095–1108
9. Herring JA, Kim HT, Browne R. Legg-Calvé-Perthes disease. Part II: prospective multicenter study of the effect of treatment on outcome J Bone Joint Surg Am.. 2004;86:2121–2134
10. Mazda K, Penneçot GF, Zeller R, et al. Perthes' disease after the age of twelve years: role of the remaining growth J Bone Joint Surg Br.. 1999;81:696–698
11. Osman MK, Martin DJ, Sherlock DA. Outcome of late-onset Perthes' disease using four different treatment modalities J Child Orthop.. 2009;3:235–242
12. Javid M, Wedge JH. Radiographic results of combined Salter innominate and femoral osteotomy in Legg-Calvé-Perthes disease in older children J Child Orthop.. 2009;3:229–234
13. Aldegheri R. Arthrodiatasis of the hip Ortopedia e Traumatologia Oggi. 1981;1:103–109
14. Salter RB, Simmonds DF, Malcolm BW, et al. The biological effect of continuous passive motion on the healing of full-thickness defects in articular cartilage: an experimental investigation in the rabbit J Bone Joint Surg Am.. 1980;62:1232–1251
15. Cañadell J, Gonzales F, Barrios RH, et al. Arthrodiastasis for stiff hips in young patients Int Orthop.. 1993;17:254–258
16. Kocaoglu M, Kilicoglu OI, Goksan SB, et al. Ilizarov fixator for treatment of Legg-Calvé-Perthes disease J Pediatr Orthop B.. 1999;8:276–281
17. Maxwell SL, Lappin KJ, Kealey WD, et al. Arthrodiastasis in Perthes' disease: : preliminary results J Bone Joint Surg Br.. 2004;86:244–250
18. Bhandari M, Zlowodzki M, Tornetta P III, et al. Intramedullary nailing following external fixation in femoral and tibial shaft fractures J Orthop Trauma.. 2005;19:140–144
19. Jones CB, Dewar ME, Aichroth PM, et al. Epiphyseal distraction monitored by strain gauges: results in seven children J Bone Joint Surg Br.. 1989;71:651–666
20. De Bastiani G, Aldegheri R, Renzi Brivio L, et al. Limb lengthening by distraction of the epiphyseal plate: a comparison of two techniques in the rabbit J Bone Joint Surg Br.. 1986;68:545–549
21. De Bastiani G, Aldegheri R, Renzi Brivio L, et al. Chondrodiatasis-controlled symmetrical distraction of the epiphyseal plate: limb lengthening in children J Bone Joint Surg Br.. 1986;68:550–556
22. Apte SS, Kenwright J. Physeal distraction and cell proliferation in the growth plate J Bone Joint Surg Br.. 1994;76:837–843
23. Hefti F, Clarke NM. The management of Legg-Calvé-Perthes' disease: is there a consensus?: a study of clinical practice preferred by the members of the European Paediatric Orthopaedic Society J Child Orthop.. 2007;1:19–25
24. Aly TA, Amin OA. Arthrodiatasis for the treatment of Perthes' disease Orthopedics.. 2009;32:817
25. Segev E, Ezra E, Wientroub S, et al. Treatment of severe late-onset Perthes' disease with soft tissue release and articulated hip distraction: revisited at skeletal maturity J Child Orthop.. 2007;1:229–235
26. Sudesh P, Bali K, Mootha AK, et al. Arthrodiastasis and surgical containment in severe late-onset Perthes disease: an analysis of 14 patients Acta Orthop Belg.. 2010;76:329–334

Legg-Calvé-Perthes disease; arthrodiastasis; no soft tissue release

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