The Chiari osteotomy. A review of 58 cases

Fifty-eight Chiari osteotomies performed in 51 patients were reviewed retrospectively. The indications for surgery were painful subluxation, instability, or poor acetabular coverage. The average age at surgery was 16 years (range, 7-45), and the average follow-up period was 40 months. The majority of the patients had congenital hip dislocation, but also included were patients with cerebral palsy, Legg-Calvé-Perthes disease, polio, infection, coxa vara, and epiphyseal dysplasia. Supplemental bone grafts were applied as needed. The functional results were unrelated to age, with 26 excellent, 28 good, and four poorly functional hips. After operation, 39 out of 41 had total pain relief, 41 out of 58 had a normal acetabular index, and 54 out of 58 had a normal center-edge angle. Trendelenburg gaits were unchanged by the Chiari osteotomy, but trochanteric transfer improved the gait in few cases.     

The Chiari pelvic osteotomy. A long-term review of clinical and radiographic results

We have reviewed a series of 94 Chiari pelvic osteotomies carried out from 1966 to 1982. In 83 hips the indication for surgery had been pain, and of these patients 73 (88%) had appreciable relief within one year of operation. The other 11 hips were all in children and were painless; in them the osteotomy had successfully stabilised progressive subluxation of the hip. At review after a mean follow-up of 10 years (range, 2 to 18 years) 68 previously painful hips were reassessed. Although function of the hips had deteriorated slowly with time, four of the seven cases with 18 years' follow-up had good function and only minor symptoms. A detailed analysis of the radiographic changes produced by the Chiari osteotomy was made, using computerised analysis of variance. The beneficial effects of the osteotomy resulted from complex changes, among which the provision of a stable fulcrum for the hip seemed to be the most important.     

Chiari's osteotomy in the treatment of Perthes' disease

Seventeen patients, with an average age of nine years 11 months, underwent 18 Chiari osteotomies for the treatment of painful subluxation of the hips following Perthes' disease. The average follow-up period was four years three months. The 13 patients reviewed clinically all did well and none complained of pain or instability. The radiographs were examined in all 17 cases. The average centre-edge angle and percentage femoral head cover were definitely improved by the operation. No significant medical displacement of the femoral head was achieved. The clinical success may result from improved femoral head coverage and diminished eccentricity. Chiari's osteotomy is recommended for adolescent patients with painful subluxation of the hip as a consequence of Perthes' disease.     

Pelvic osteotomy techniques and comparative effects on biomechanics of the hip: a kinematic study

Dysplasia of the hip is characterized by malpositioning of the proximal femur in a shallow acetabulum, providing deficient femoral head coverage. This abnormal relationship leads to altered biomechanics of the hip joint, as predicted by measurement of kinematic parameters such as increased load over reduced acetabular weight-bearing area, leading to increased joint contact stresses, which subsequently results in secondary osteoarthrosis, pain, and disability. To prevent these sequelae, particularly in children and younger adults, various osteotomies have been performed with varying degrees of success. The goal of this study was to devise a simple and reproducible laboratory method to perform a kinematic analysis of the individual and comparative effects of 5 commonly performed pelvic osteotomy techniques: Chiari pelvic osteotomy, Salter innominate bone wedge osteotomy, Steel triple pelvic osteotomy, T?nnis triple pelvic osteotomy, and Ganz periacetabular pelvic osteotomy. The aim was to determine which of the osteotomy techniques caused greater correction in most of the kinematic parameters used to estimate changes in the biomechanics of the hip joint. Our hypothesis was that pelvic osteotomies such as Chiari and Salter produced favorable changes and were relatively easily reproducible, but that more biomechanical correction in all planes would be achieved by the relatively more complex triple innominate bone and Ganz osteotomy.     

Long-term survivorship of hip shelf arthroplasty and Chiari osteotomy in adults

The current authors retrospectively assessed 56 hip shelf arthroplasties (48 patients) with a mean followup of 17 years (range, 15-30 years) and 89 Chiari osteotomies (82 patients) with a mean followup of 13 years (range, 6-25 years) done in adults with painful hip dysplasia. Preoperative joint space narrowing was observed in 32 of 56 shelf arthroplasties and in 67 of 89 Chiari osteotomies. Survival rates, using hip replacement as the end point, were 37% (20% to 54%) at 20 years for shelf arthroplasty and 68% (54% to 81%) at 18 years for Chiari osteotomy. The severity of preoperative arthrosis was the main factor that impaired the survivorship of shelf arthroplasty and Chiari osteotomy. With arthritic changes without joint space narrowing, the 18-year survival rates were 83% (69% to 97%) for shelf arthroplasty and 94% (89% to 99%) for Chiari osteotomy. Shelf arthroplasty is best indicated for moderate dysplasia (center edge angle >0 degrees) without severe arthrosis. Chiari osteotomy is best suited for severe dysplasia (center edge angle <0 degrees) especially without or with slight arthrosis. Chiari osteotomy also can be a salvage procedure when marked joint space narrowing is present but only if it is related to severe dysplasia (center edge angle <0 degrees).     

Chiari骨盆截骨术的生物力学基础及临床应用（附36例报告）

本文报告应用Ｃｈｉａｒｉ骨盆截骨术治疗髋臼发育不良、扁平髋等３６例４１个髋。３２个髋平均随防４年４个月。优良者２７个髋，占８４．３７％。术后Ｘ线片显示，截骨均获骨性愈合，髋臼对头覆盖完全，头臼相称。髋臼发育不良者，ＣＥ角平均增加２０°。作者分析此术式后认为：Ｃｈｉａｒｉ手术能增加髋臼面积，减少股骨头单位压强，截骨内移后能增加肌力臂，减少重力臂，从而减少髋关节的载荷，降低关节内压及髂骨髋内压，有利于缓解“休息痛”。为此提出成人先天性髋臼发育不良、扁平髋、股骨头无菌坏死以及髋的骨关节炎病人适合行此手术。     

The results of Chiari pelvic osteotomy in adolescents with a brief literature review

Purpose Chiari medial displacement osteotomy is a procedure that uses the cancellous bone of the ilium to contain the femoral head and bear weight. It is the most contraversial osteotomy of the hip joint. This study was therefore conducted to determine the results of this osteotomy with mid-term follow-up in children. Methods From 1995 to 2004, 20 Chiari pelvic osteotomies (in 18 patients) were performed. There were 15 male and 3 female patients. The average age at operation was 12.6 years and the mean follow-up was 54 months. The operative technique was as described by Chiari. An iliofemoral approach was used without utilizing a traction table. If there was anterior or anterolateral uncoverage of the femoral head, bone graft augmentation was performed. Results The angle of the osteotomy averaged 12°, with the distance from the acetabulum averaging 3.2 mm. The average displacement was 42%. Of the 20 Chiari osteotomies, 11 were categorized as excellent, 8 as good and one as fair in terms of clinical and radiological results. Student’s t test statistics showed improvements in all radiologic parameters of the hip joint (Sharp angle, center-edge angle and coverage of the femoral head). Graft resorption was observed in 25% of the patients. Conclusion There are very rare indications of Chiari osteotomy in patients younger than 10 years. Because of the high rate of graft resorption, Chiari osteotomy should be the last treatment option when there is anterior or anterolateral uncoverage of the hip joint.     

Chiari pelvic osteotomy for osteoarthritis secondary to hip dysplasia. Indications and long-term results

Of 142 Chiari pelvic osteotomies for osteoarthritis in dysplastic hips, most performed by Chiari himself, we were able to review 82 and obtain information about 18 by questionnaire. All patients were over 30 years of age at operation; follow-up averaged 15.5 years. Twenty hips had undergone secondary total hip replacement. The outcome was good in 75%, fair in 9% and poor in 16%. High osteotomies all gave good results, and the result also depended on adequate medialisation. Statistics were worse for patients over 44 years of age at the time of operation. For osteoarthritis secondary to hip dysplasia, the Chiari pelvic osteotomy is an alternative procedure to early hip replacement. In contrast to intertrochanteric osteotomy, it has the advantage of facilitating the implantation of an acetabular prosthesis should arthroplasty become necessary at a later stage.     

Chiari osteotomy in Legg-Calve-Perthes disease

A retrospective study of 22 Chiari osteotomies in 21 children with severe Legg-Calve-Perthes disease is presented. All cases were studied at skeletal maturity. The average age at surgery was 8.5 years with an average follow-up of 6.1 years. Four hips were classified as Catterall group III and the remaining hips as group IV. Arthrography was used preoperatively to measure the femoral head sphericity, the femoral head coverage and the eccentric index. The same parameters were studied on radiographs at skeletal maturity. Chiari osteotomy provided an improvement in the femoral head coverage and hip congruency. Radiographs showed progressive spherical remodelling of the femoral head and improvement of the concentricity. One hip required premature total hip replacement.     

Clinical results of rotational osteotomy for treatment of avascular necrosis of the femoral head

We reviewed the results of seven transtrochanteric rotational osteotomies done for painful avascular necrosis of the femoral head. The results tended to deteriorate over the time. Despite the overall unsatisfactory results at final follow-up, the procedure was valuable as it delayed the necessity for total hip arthroplasty. Six patients underwent total hip arthroplasty an average of 6.7 years following the osteotomy. The procedure is technically difficult and is associated with a high risk of late complications, mainly progressive collapse, further necrosis and increased osteoarthritic changes.     

A computer model for evaluating the osteotomy parameters of Chiari pelvic osteotomy

This study was conducted to evaluate the effect of the various osteotomy parameters on the biomechanical aspects of the hip joint on a computerised model. The data of the radiographs and a three-dimensional (3D) CT scan of six patients with coverage deficient hip joint were used to construct a 3D computer model. Then Chiari type osteotomies were simulated using various heights, angles and fibrocartilage thicknesses. A new angle called the mid acetabular center edge (MACE) angle was defined in a mid coronal CT cut. The optimum displacement for obtaining the maximum coverage averaged 73%. The angle and height of the osteotomy had a significant effect on the MACE angle (P value < 0.01). Our findings of these Chiari parameters may change the results of the osteotomy. The probability of adapting the proximal osteotomy segment to a deformed femoral head was explained by the model and a modified osteotomy “multiple height osteotomy” was proposed.     

Chiari pelvic osteotomy in the treatment of hip dysplasia in adults]

INTRODUCTION: [corrected] The aim of the study is early results evaluation of Chiari pelvic osteotomy. MATERIALS AND METHODS: In the years 1997-2003 36 patients (26 women and 10 men) in the age from 16 to 50 years old were operated on because of hip joint dysplasia. The indications for operative treatment were: pain, age less than 50 years, insufficient femoral head coverage without evidence of arthritic changes on X-ray. RESULTS: There were no intraoperative and postoperative complications. Harris Hip Score improved from 85 points before operation (from 82 to 90 pts.) to 95 points (from 92 to 100 pts.) after operative treatment. There was pain relief in most of the patients after osteotomy. Osteotomy healing was seen on X-ray examination usually after 6-12 weeks in 33 patients. Delayed osteotomy union till 6th postoperative month without influence on clinical hip improvement was seen in 3 patients. The increase in Wiberg CE angle from average 17.2 degrees (from 3 to 33 degrees) before operation to 44.9 degrees (from 19 to 78 degrees) after operation was statistically significant p< 0.00045. There was no loss in osteotomy correction. CONCLUSION: Supraacetabular osteotomy decreases pain, and increases hip function. Improvement in hip biomechanics and increase in femoral head coverage may lead to decrease in development of hip joint arthritic changes and time preserve before total hip arthroplasty.     

Resection of the obturator nerve for analgesic treatment of degenerative-deforming changes of the hip joint]

Resection of the obturator nerve in hip joint arthritis can eliminate or decrease pain depending on the obturator nerve share in the hip joint innervation. From 1986 to 1988 34 obturator neurectomies were performed in painful hip arthritis patients with temporary or permanent contraindications for hip arthroplasty. In 21 from 30 patients followed-up at least 3 months partial or total relief of pain was found. Extrapelvic obturator neurectomy technique and indications for this procedure were presented.     

Long-term results of Salter and Chiari hip osteotomies in developmental hip dysplasia

When conservative treatment of developmental hip dysplasia (DDH) does not render satisfactory results, surgical methods are indicated to gain a maximum of joint posture and stability. To assess the efficiency of these surgical procedures, the long-term results of the most often used pelvic osteotomies were examined. As common evaluation scores do not apply for DDH, we developed a specific score system of 100 points to integrate subjective factors such as patient’s complaints with objective functional and radiological findings after surgical intervention. Our survey with an average postoperative follow-up examination of 10 years indicated that Salter’s innominate osteotomy can render long-term pain relief and enable normal hip development, whereas Chiari’s capsular arthroplasty does not. Here, subjective patient complaints do not correlate with clinical and radiological findings, which leads to unsatisfactory results. Ideally, patients aged 2–3 years can undergo Salter’s innominate osteotomy whereas the Chiari osteotomy should be considered for patients older than 15 years. Even under optimal surgical conditions, Chiari’s osteotomy cannot significantly prevent the development of joint arthritis. Undoubtedly, late results of both surgical procedures are dependent upon the initial stage of DDH. Additional upper femoral correction osteotomies have no further influence on hip development. Received: 22 May 1995     

Treatment of the painful chronically dislocated and subluxated hip in cerebral palsy with hip arthrodesis

The purpose of this study was to evaluate 14 painful dislocated hips in patients with spastic cerebral palsy, treated with hip arthrodesis and internal fixation. The mean age at the surgical procedure was 15 years and 5 months. The mean follow-up period was 5 years and 3 months. All patients showed bone union, pain relief, and postural improvement. Hip arthrodesis is a reasonable option in treating painful spastic subluxated and dislocated hips in patients with cerebral palsy, especially if it is unilateral and the patient has weight-bearing function.     

Dome (modified Chiari) pelvic osteotomy: 10- to 18-year followup study

Ninety-six dome (modified Chiari) pelvic osteotomies in 87 patients with pain and disability because of osteoarthrosis secondary to hip dysplasia were reviewed. The mean age of the patients at the time of surgery was 29 years (range, 16-55 years). The mean followup was 13 years (range, 10-18 years). Forty-one hips were classified into a hip dysplasia stage, 32 hips into an early stage of osteoarthrosis, and 23 hips into an advanced stage of osteoarthrosis according to the radiographic grading of the Japanese Orthopaedic Association. The average preoperative Merle d'Aubigné and Postel hip score was 13.8, and the average score at final followup was 16.6. Excellent or good results with a score greater than 14 were achieved in 96% of the hips at final followup. Radiographically, signs of progression of osteoarthrosis were not seen in 87% of the hips. Osteoarthrosis progressed during the postoperative course in 13% of the hips. Four patients (four hips) eventually had a total hip arthroplasty at 13.8 years (range, 12.5-15.3 years) after surgery. The survival rate of dome pelvic osteotomy, using clinical failure as an end point, was 82% at 15 years. Using radiologic failure as an end point, 61 hips in 54 patients (survival rate, 78%) survived at 15 years. Using hip replacement as an end point, 92 hips in 83 patients (survival rate, 82%) survived at 15 years. Dome pelvic osteotomy is an excellent and effective operation for pain relief and functional maintenance of the hip.     

Role of Chiari osteotomy in treating degenerative hip arthritis: A review

Chiari pelvic osteotomy (CPO) or medial displacement pelvic osteotomy is a surgical procedure of making a congruent shelf above intact hip joint by using the cancellous bone of ilium along with capsular interpositioning to contain the femoral head and bear weight. CPO is usually considered a salvage procedure indicated in patients with dysplastic acetabular sockets as a part of developmental hip dysplasia. It has been widely performed for several decades but since 1990s number of CPO procedures has decreased because of use of other pelvic osteotomies, total hip arthroplasty (THA), ultrasound screening and narrowing indications for this procedure. However, CPO is not a historical procedure and it has viable indications in modern orthopaedic surgery, especially in patients who prefer joint-conservating procedure or in situations when THA is not feasible. Moreover, keeping the native hip as long as possible should be preferred modern orthopaedic approach. The Chiari osteotomy can produce excellent results in patients who have right indications and when other procedures are not suitable. On the other hand, there are several disadvantages of this procedure such as narrowing of the pelvis, shortening of the limb and risk of sciatic nerve palsy. With in-depth analysis of literature, we discuss indications for CPO, surgical technique of CPO, THA conversion rate after CPO, the interval from the CPO to THA and CPO survival rate.     

Subtrochanteric valgus osteotomy for chronically dislocated, painful spastic hips

BACKGROUND: Many treatments have been proposed for a painful chronically dislocated hip in a child with spasticity who is unable to walk. The valgus subtrochanteric femoral osteotomy was originally described as a treatment for a missed congenital hip dislocation in a young adult who was able to walk. The purpose of this study was to investigate the outcomes of a modified Hass subtrochanteric valgus osteotomy for the treatment of symptomatic chronic hip dislocations in patients with spasticity due to neuromuscular disorders. METHODS: Patients were identified by surgical codes. Medical records were reviewed for surgical indications, complications, and results. Preoperative and postoperative radiographs were assessed. Caregivers were contacted and asked to complete a brief survey detailing the pain that the patient experienced with daily activities before and after surgery as well as other information. RESULTS: Thirty-one Hass osteotomies in twenty-four consecutive patients were performed by one surgeon between 1995 and 2005. Although fifteen patients (63%) had at least one complication (including urinary tract infection, pneumonia, hardware failure, and heterotopic bone formation), the majority of the patients were doing well at an average of forty-four months postoperatively. The duration for which the patient could sit, ease of transfers, and ease of diaper changes had all improved according to the caregivers. Fourteen of fifteen caregivers who replied to the question stated that they were satisfied with the operative results and would have the procedure done again if they had the decision to make. CONCLUSIONS: The modified Hass osteotomy provides children who have symptomatic hip dislocations due to neuromuscular disorders with reproducible pain relief and improves ease of positioning by their caregivers. The complication rate, although high, was comparable with that of similar surgical procedures in this patient population. Concurrent femoral head resection at the time of the proximal femoral osteotomy was not necessary in this group of patients.     

Dynamics of hip joint remodeling after Chiari osteotomy: 10 patients with neuromuscular disease followed for 8 years

We analyzed the development of 10 hips in 10 consecutive patients with neuromuscular disease (9 with spasticity, 1 with Charcot-Marie-Tooth disease) who had undergone Chiari osteotomy for painful hip subluxation or dislocation. The patients were 11 (5-19) years old at surgery and follow-up time was 8 (6-11) years.

The Chiari osteotomy particularly improved and maintained femoral head coverage. These parameters did not show the postoperative deterioration noted in some other studies. The osteotomy did not improve femoral head lateral displacement. Throughout the postoperative period, the configuration of the proximal femur and the height of the joint cartilage were unchanged and undisturbed, indicating that osteotomy did not place excessive or uneven pressure on the femoral head.

The ambulatory status of the patients was dependent on the severity of the underlying disease, and was not improved by osteotomy. However, pain associated with subluxation or dislocation was reduced in 9 of the patients.     

Acetabular Reconstruction With Chiari Pelvic Osteotomy : Report of 2 Cases

We performed cementless total hip arthroplasty combined with acetabular reconstruction with Chiari pelvic osteotomy on 3 hips in 2 patients. This procedure increased the osseous coverage of the shell and decreased the load around the hip by medialization of the hip center. Osteosynthesis of the proximal and distal bone fragment was performed using a shell with screws. Nonunion between the proximal and distal fragments was not noticed to include the case with small contact area. Postoperative dislocation had not occurred in these cases as of 1 year after surgery. This method may be an effective solution for severe dysplasia and revision surgery.