Copa de doble movilidad: aciertos, riesgos y enseñanzas / Dual mobility cup: successes, risks and lessons learned

Resumen: Se hace una revisión narrativa del desarrollo y evolución hasta el momento de las copas de doble movilidad enfocada en sus aciertos, fallas y enseñanzas. Se mencionan las herramientas con las cuales contamos para prevenir y en su caso, tratar la luxación protésica de cadera y los principales problemas que presentan. El principal objetivo de esta publicación es hacer reflexiones y comentarios en cuanto a lo que debemos estar atentos ante un mundo de diseños que actualmente existen en el mercado con una diversidad de diseños, materiales, aleaciones, tipos de polietileno, etc. Se analizan los problemas que enfrentan algunos modelos para obtener una fijación estable a largo plazo, el problema que posiblemente representan los diferentes modelos contemporáneos de doble movilidad y sus resultados clínicos. Se discuten y comentan los puntos anteriores y se establecen conclusiones y recomendaciones.

Abstract: A narrative review of the development and evolution to date of the double mobility cups is made, focusing on their successes, failures and teachings. The tools with which we have to prevent and treat prosthetic hip dislocation and the main problems are mentioned. The main objective of this publication is to make reflections and comments about what we should be attentive to in a world of designs that currently exist in the market with a diversity of designs, materials, alloys, types of polyethylene, etc. Some models are found to obtain a stable long-term fixation, the problem that potentially represents the different contemporary models of double mobility and their clinical results. The previous points are discussed and commented and conclusions and recommendations were reached.

Efficacy analysis of T?nnis triple osteotomy for developmental dysplasia of the hip in older children / 中华实用儿科临床杂志

Objective:To explore the outcomes of T?nnis triple osteotomy for developmental dysplasia of the hip (DDH) in older children.Methods:Clinical data of 21 children (22 hips, 12 left and 10 right hips) treated by T?nnis triple osteotomy from October 2016 to June 2019 were retrospectively analyzed.There were 8 males and 13 females with a mean age of operation at 13.5 (8.6-16.8) years.Based on the T?nnis classification, all the cases were in Grade Ⅰ.Statistical analysis was performed using the SPSS 22.0 statistical software.Results:All recruited patients were followed up for 1.5-3.5 years.Compared with preoperative values and those at the last follow-up visit, the mean Sharp acetabular angle of the affected side recovered from 53.5°±5.2° to 40.8°±2.3°.The mean center-edge angle increased from 10.5°±2.9° to 35.4°±5.6°.The mean acetabular roof angle decreased from 38.6°±2.8° to 6.7°±1.3°.The mean acetabular head index enhanced from (54.3±5.2)% to (86.2±2.7)%.The differences between the preoperative and postoperative values were statistically significant ( t=24.3, 17.6, 50.1, 27.5; all P<0.05). According to the Harris classification, there were 17, 3 and 2 hips achieved excellent, good and fair outcomes at the last follow-up visit, respectively, with the percentage of excellent and good outcomes up to 90.9%(20/22 hips). Accor-ding to the Severin radiographic classification, 8, 12 and 2 hips were in grade Ⅰ, Ⅱ, and Ⅲ, respectively, with the percentage of excellent and good hips at 90.9%(20/22 hips). At the last follow-up visit, the bone healing of iliac and pubic bones was well, and the nonunion of ischial bones were reported in 3 cases (13.6%). Conclusion:The outcome of the T?nnis triple osteotomy is satisfactory for DDH in older children.

Effects of sevoflurane and propofol on coagulation function and postoperative recovery in children with congenital dislocation of hip joint / 中国输血杂志

【Objective】 To investigate the effects of sevoflurane and propofol on coagulation function and postoperative recovery in children with congenital dislocation of hip joint. 【Methods】 A total of 92 children with congenital dislocation of hip joint admitted to our hospital from June 2017 to June 2020 were studied. According to the random sampling method, the subjects were divided into sevoflurane group and propofol group with 46 cases in each group, Sevoflurane and propofol were administered to the sevoflurane group and the propofol group during anesthesia induction and maintenance, respectively, The changes of hemodynamic index, body temperature, coagulation function before and after operation, postoperative outcome and the incidence of complication were compared between the two groups at different time points of anesthesia. 【Results】 Few significant differences in SBP, DBP, HR at different time points of anesthesia were noticed between the two groups (P>0.05). The body temperature of children in the study group at T1, T2 and T3 was significantly lower than that of the sevoflurane group (P0.05) between the two groups. In the propofol group, there was no statistically significant difference in coagulation indexes before and after surgery (P>0.05), while in the sevoflurane group, all coagulation indexes after surgery were significantly higher than before surgery (P<0.05). The retention time, wake time, extubation time and hospital stay length of the children in the propofol group were significantly shorter than those in the sevoflurane group (P<0.05). The incidence of complication in the propofol group was significantly lower than that of the sevoflurane group (P<0.05). 【Conclusion】 Compared with sevoflurane, propofol anesthesia maintenance is more beneficial to reduce the incidence of intraoperative hypothermia, and does not affect the hemodynamic indexes and coagulation function of the body, which is of positive significance for promoting postoperative anesthesia recovery and shortening the recovery time of children with congenital dislocation of hip joint.

Analysis Of Femoral Neck Anteversion In Dry Adult Bones: A Morphometric Study

Introduction: The femoral neck anteversion can be defined as the angle between femoral bicondylar plane and aplane passing through the centre of the neck and head of femur. Adult femoral anteversion has been documentedat the range between 7-16 degrees.This angle is widely recognized as an important factor for hip stability. Thepresent study aimed to evaluate the normal anteversion range in adult Indian femur which would be of great helpin explorative orthopedic procedures and in designing of hip prosthesis.Materials and Methods: Study conducted in 202 femurs of 94 male (48 right and 46 left) and 108female bones (52right and 56 left). And the angle was measured using Kingsley Olmsted Method.Observation and Results: The mean value of anteversion angle of femurwas 7.61 degrees for male and 12.71degrees for females.Mean anteversion angle for both male and female femur was 10.37 degrees. Retroversionwas observed in 10 femurs(5%) and neutral version was observed in12 femurs (5.9%).Conclusion:Determining the anteversion angle is crucial for the diagnostic and therapeutic planning of patientswith various pathologies such as hip development dysplasias, cerebral palsy, varum thigh, flat thigh,epiphysiolysis, congenital club foot, congenital dislocation of the hipand other development abnormalities.Statistical analysis revealed sexual dimorphism in anteversion in Indians being greater among females thanmales

Prevention measures and reasons analysis of the elder patients early anti-dislocation after total hip arthroplasty / 现代临床护理

Objective To explore the reasons and preventive measures of early dislocation after total hip arthroplasty in elder patients. Method A retrospective study was done to analyze dislocation time, reason and time of 168 elderly patients with early anti-dislocation after total hip arthroplasty in joint surgery. Results Only 7 patients (4.1%) had type I joint dislocation, including 2 male and 5 female patients aged 65~89 years. The dislocation happened in 4~5 weeks postoperatively, mainly resulting from hip joint over flexion when urinating in bed, sleep-turning, loaded-moving, walking and stoop and diachoresis. Conclusions For the elderly patients after total hip replacement, it is type I dislocation which happened 4 ~ 5 weeks after operation, more femal than male, reasons including over-exercrse. Effective prevention measures includes regular rehabilitation training, early precautions enhanced mental support and safety nursing.

Artificial total hip arthroplasty and hip-self procedure in the treatment of congenital dislocation of hip / 中国组织工程研究

BACKGROUND:The effects of artificial joint replacement, osteotomy and reconstruction in the treatment of Crown Ⅳ-type congenital dislocation of hip in adult are not very satisfied. OBJECTIVE:To evaluate the effect of artificial total hip arthroplasty and hip-self procedure in the treatment of Crown Ⅳ-type congenital dislocation of hip in adult patients. METHODS:Twenty-three adult patients with Crown Ⅳ-type congenital dislocation of hip were treated with artificial total hip arthroplasty and hip-self procedure. There were 2 males and 21 females with an average age of (24.26±3.56) years ranging 20 to 35 years. The effect was evaluated according to the Harrris evaluation standard, and the statistical analysis was performed. RESULTS AND CONCLUSION:Al of the patients were fol owed-up for 12-60 months, averaged of (26.60±13.16) months. Statistical comparison with the SPSS 19.0 system showed there was significant difference of the Harrris scores between preoperation and postoperation period (P<0.05). The artificial total hip arthroplasty and hip-self procedure can be used to reconstruct the normal function of hip joint, relieve pain and increase the joint stability, which is considered as the best method for the treatment of Crown Ⅳ-type congenital dislocation of hip in adult.

Patient Accompanied with Simultaneous Anterior Dislocation of Hip and Anterior Dislocation of Knee : A Case Report

We are reporting a case that a 61-year-old patient who had simultaneous anterior dislocation of left hip and anterior dislocation of right knee after fall from a height injury was treated by closed reduction respectively.

Prevalence of talipes equinovarus, congenital dislocation of the hip, cleft lip/cleft palate, Down syndrome and neural tube defects among live newborns in Anuradhapura, Sri Lanka.

Objective To determine the prevalence of talipes equinovarus, congenital dislocation of the hip, cleft lip/cleft palate, Down syndrome and neural tube defects among live newborns at Anuradhapura General Hospital, Sri Lanka. Method Babies born from February 2002 to January 2003 were examined for the above five congenital anomalies. Anomalies were recorded in a register and live birth prevalence rate (LBPR) for each anomaly was calculated. Results 9105 newborns were examined for the 5 selected congenital anomalies. LBPR per 10,000 live births of the 5 anomalies were as follows: talipes equinovarus 31.8, congenital dislocation of hip 26.3, cleft lip/cleft palate 21.9, Down syndrome 20.8 and neural tube defects 13.2.

Analysis about reason of congenital infantile coxa vara being misdiagnosed as infantile dislocation of hip join / 中国矫形外科杂志

[Objective]To analyze reason of congenital infantile coxa vara to be misdiagnosed as infantile dislocation of hip joint.[Method]There were 6 patients(6 hip join)congenital infantile coxa vara being misdiagnosed as infantile dislocation of hip join in 54 patients(73 hip join)and treated by expectant treatment as infantile dislocation of hip join.The curative effect of 6 patients were not good,after serious medical examination,careful reading image data,paying attention to curative effect,6 patients were confirmed to be diagnosed as infantile dislocation of hip join and not infantile dislocation of hip join.[Result]The features for diagaosis of congenital infantile coxa vara were:the big greater trochanter of femur and its position moving up,short spacious neck of femur,spacious medial blank in hip joint,superposed neck of femur and lesser trochanter of femur,praeter propter exponent of acetabulum,acceptable succession of Shenton’s line,enlarged angle of femoral head epiphysis,late center of ossification,incorporated abnormity such as breves femoral bone,bowing of femoral bone,abortive clavicle and bones of cranium,equines.[Conclusion]The second center of ossification of femoral head is appeared 6～9 monthes after birth,and it is difficult to discriminate congenital infantile coxa vara and infantile dislocation of hip join before this.Early to realize symptom,physical sign and character of image of congenital infantile coxa vara is significant for correct diagnosis and can avoid misdiagnosis and mistreatment.

Reinfusion of blood salvage during the operation of the developmental dysplasia of the hip in children / 中国矫形外科杂志

[Objective]To evaluate the results of intraoperative autologous blood transfusion in pediatric orthopaedic operation.[Method]Intraoperative blood salvage was reinfusioned in 17 patients by Cell Saver 5.The volume of reinfusion blood and complications were recorded.[Result]Among 17 patients,an average of(171?53)ml autologous blood was transfused intraopratively.The use of Cell Saver 5 was directly responsible for a 80% reduction in the total amunts of homologous blood.Four patients has experienced transient hemoglobinuria.No other complications appeared.[Conclusion]Reinfusion of blood salvage during pediatric orthopaedic operation is safe and effective.It is able to reduce the amount of homologous blood transfusion.

Femoral head coverage rate of CT in evaluation of Salter osteotomy for developmental dislocation of hip in children / 上海第二医科大学学报

Objective To analyse the femoral head coverage rate of CT in evaluation of Salter osteotomy for developmental dislocation of hip(DDH) in children. Methods Thirty-eight patients with unilateral DDH for Salter osteotomy were enrolled,and X ray photography of pelvis and spiral CT scanning of femoral articulation were performed one week before and 6 months after Salter osteotomy.The femoral head coverage rate of X ray and that of CT were calculated and compared.Another 38 children with normal femoral articulation were served as controls. Results The femoral head coverage rate of X ray was significantly higher than that of CT in patients with DDH(P

Marginal compression fractures of acetabular posterior wall with posterior dislocation of hip / 中华创伤骨科杂志

Objective To explore the diagnosis and treatment of marginal compression fractures of acetabular posterior wall with posterior dislocation of hip. Methods Eleven patients with marginal compression fractures of acetabular posterior wall and posterior dislocation of hip were retrospectively reviewed. Their conditions were all confirmed by CT scan before operation. AH the patients were treated by ORIF (open reduction with internal fixation) and the compressed bones were elevated with bone grafts. All the fractures were fixed with reconstruction plating. Results The mean follow up was 32. 4 months (5 to 56 months) . The results of modified d'Aubigne and Postel score system were excellent in four patients, good in four, fair in two, and poor in one. The good to excellent rate was 72. 7%. Conclusion It is likely for patients with fractures of acetabular posterior wall and posterior dislocation of hip to have marginal compression fracture which can be definitely diagnosed by CT scan preoperatively. Good results can be obtained by elevating part of the compressed marginal bone with bone grafting, because it can improve the reduction of acetabulum and femoral head.

Bikini Cut Treatment for Childhood Developmental Dislocation of Hip / 实用儿科临床杂志

0.05).But in Bikini cut group,there was no intraoperative lateral femoral cutaneous nerve injury,and operation cut was so hidden and so parents were willing to accept the operation.If it was hecessary to carry out femur rotation osteotomy and internal fixation of femur,the steel plate accords with the principle of tension band,so the fixation could be stable and the fracture can easily heal up.Conclusions In the treatment of DDH,Salter pelvic osteotomy through Bikini cut has exact clinical efficacy comparing with S-P cut,and its operation cut is safe,hidden,and there is rare injury to joint function after operation.

Clinical analysis of acetabular fracture and hip dislocation complicated with sciatic nerve injuries / 中华创伤骨科杂志

Objective To investigate the clinical characteristics and the causative mechanism of acetabular fracture and dislocation of hip complicated with sciatic nerve injuries. Methods A retrospective analysis was done for 155 cases (159 sides) of acetabular fracture, dislocation of hip, or acetabular fracture combined with hip dislocation, 35 of which were complicated with sciatic nerve injuries. The epidemiological features of acetabular fracture and hip dislocation, the incidence, and relationship between sciatic nerve injury and classifications of acetabular fracture and dislocation of hip were analyzed. Results 81.3%of the patients were male. The ages of 86.5%of the patients ranged from 20 to 50 years old. 83.9%of the cases were injured in traffic accidents. The incidence of sciatic nerve injury was 22.01%in all the patients, 17.19%in patients with acetabular fracture, 12.90%in patients with posterior wall, and 36.36%in patients with acetabular fracture combined with posterior dislocation of hip. Conclusions A road traffic accident is the major causative factor for acetabular fracture and dislocation of hip. Most victims are male. Sciatic nerve injuries largely happen in cases of acetabular posterior wall fracture and posterior column fractures combined with posterior dislocation of hip. Peroneal nerve injuries are the most common type of sciatic nerve injury.

The Results of Treatment in Developmental Dislocation of the Hip between 6 and 24 Months Old / 대한정형외과학회잡지

PURPOSE: To evaluate the outcome of treatment for developmental dislocation of the hip (DDH) in children in whom the treatment was delayed until they were 6 to 24 months old. MATERIALS AND METHODS: Fifty two hips of 48 children between 6 and 24 months old, who have not been treated for DDH were selected for this study. The treatments for these children were closed reduction in 16 hips and open reduction in 36 hips. Patients were followed-up for 11 years on average and for 5 years at minimum. RESULTS: According to Severin's classification, 39 hips (75%) were included in the `satisfactory group', while 13 hips (25%) were `unsatisfactory'. The `unsatisfactory group' consisted of 7 hips showing an impaired secondary ossification center in the acetabular rim, 5 hips with persistent resubluxation after weaning the orthosis, and one hip showing severe coxa magna. Additional bony procedures for the underdeveloped acetabuum and/or proximal femur were required in 12 hips, except for one showing severe coxa magna. CONCLUSION: The radiological outcome of DDH in children in whom the treatment was delayed until 6 to 24 months old was satisfactory in 39 hips (75%). Unsatisfactory hips required additional bony procedures, which we expect will improve the final outcome.

Developmental coax vara, Operative treatment / 대한정형외과학회잡지

Hip arthrograghy is a valuable procedure for visualization of the intrinsic obstructive factors impeding closed reduction and for critical assessment of quality of reduction in developmental dislocation of the hip. The authors have analyzed 25 cases of developmentally dislocated hips in 24 patients who have been followed up for more than 1 year postoperatively by roentgenographies and arthrographies. Among them 16 cases in 16 patients who had been treated by closed reduction according to acceptable quality of initial reduction were studied to estimate a value of arthrography and to evaluate an outcome of closed rediction performed on the base of an arthrographic finding. The following results were obtained. 1. The frequency of the common arthrographic observations were assessed. Medial dye columns identifying the depth of reduction were observed 25 cases(100%), configuration of osteocartilaginous structures in 24 cases(96.0%), limbus in 24 cases(96.0%), and ligamentum teres in 18cases(75.0%). 2. Good closed reduction classified according to Race and Herring on initial arthrography was associated with rapid improvement of acetabular angle and the CE angle and low incidence of avascular necrosis, compared with adequate or poor reduction. 3. In cases of initial good and adequate reductions, initial AP arthrograms showed some dye filling shadows owing to folding or redundancy of lax joint capsule of the dislocated hip after reduction just lateral to the limbus, of which finding decreased markedly on the second arthrograms. 4. The widths of medial dye column decreased with time during the first postoperative 7 weeks by an average of 0.5mm in cases with initial good quality of reduction, 3.5mm in adequate reductions and 0.5mm in poor reductions. 5. In cases with adequate closed reduction on initial arthrogram, but without substantial decrease in width of medial dye column on the second arthogram the outcome was poor. In those cases with decrease in width of medial dye column on the second arthrogram compared with initial arthogram, the shorter the period of immobilization in a plaster cast was, the worse eventual result was. 6. We think that hip arthography is a helpful procedure for visualization of obstacle obstructing closed reduction and for determination of treatment modality in developmental dislocation of the hip.

Coxa Magna after Open Reduction of Developmental Dislication of Hip: Contributing factors and Acetabular development / 대한정형외과학회잡지

The authors reviewed 50 patients of congenital dislocation of the hip who had surgical treatment at the Department of Orthopedic Surgery, Seoul National University Children's Hospital from October, 1985 to August, 1993. We investigated the contributing factors to coxa magna after surgical treatment and it's relationship to the avascular necrosis of femoral head, and observed the influnce of coxa magna on the development of the hip joint. Coxa magna was defined as a femoral head with the greatest diameter 15% greater than the opposite side. To assess the development of the acetabulum in the hips with coxa magna, radiographical horizontal and vertical parameters were measured preoperatively, and at postoperative 1 year, 2 year, and 3 year or more. Twenty-one of fifty hips had coxa manga. The incidence of coxa magna increased in patients who had open reduction at younger age(average 30 months), compared to older age(average 44 months). Neither femoral osteotomy nor pelvic osteotomy increased statistically the incidence of coxa magna. Avascular necrosis of femoral head did not necessarily resulted in coxa magna. There were not statistically significant differences in the coverage ratios of femoral head by the acetabulum between coxa magna positive and negative groups, because lateral acetabular growth accompanied in accordance with enlargement of femoral head in the majority of cases with coxa magna. Open reduction alone caused concomitant vertical overgrowth of ipsilateral hemi-pelvis with resultant pelvic tilt and leg length inequality(IHD>5mm, upto 2cm) in 6 of 10 cases. The patients, who had coxa magna with good radiological results by Severin's classification, underwent open reduction at younger age and had lesser enlargement of the femoral head, compared to those with fair or poor results.

Treatment of Congenital Dislocation of the Hip with the Pavlik Harness / 대한정형외과학회잡지

The congenital dislocation. of the hip is a common congenital disease in the orthopedic field. It is well known that the early diagnosis and effective treatment is very important for the patient to provide a favorable function in the whole life. The Pavlik harness made an important contribution to the treatment of children before standing age. The authors report a clinical experience of 34 patients(35 hips) with congenital dislocation of hip who were treated with Pavlik harness at the Department of Orthopedic Surgery of Chonnam University Hospital. There were total 230 patients(237 hips) diagnosed as congenital dislocation of hip for 10 years from 1978 to 1987. Fifty-one patients(52 hips) of them were treated with Pavlik harness. Only 34 patients(35 hips) were included in this study excluding 17 patients(17 hips) because of inappropriate records or follow-up. The follow-up period ranged from 1 year to 6 years with an average of 2 years and 5 months. The results are as follows ; 1. The most patients were girls, comprising 33 girls and 1 boy. 2. The age of children was 124.6days in average ranging from 13 to 201 days. 3. Of the 35 hips treated with Pavlik harness, satisfactory reduction was obtsined in 30 hips(85.7%). For 5 failed cases, the authors performed closed reduction under the general anesthesia in 3 cases and open reduction in 2 cases. 4. The causes of reduction failure were impossible reduction in 3 cases, nonconcentric reduction in 1 case and repeated redislocation in 1 case. 5. The acetabular and metaphyseal-edge angle improved from the average 33 and 5.8 degrees at the first visit to the average 19.9 and 30.6 degree at the final follow-up (20.7 and 29.2 degrees in normal side). 6. When compared with the value of the 30 hips which were reduced successfully, the initial acetabular angle of 5 failed cases was similar but the metaphyseal-edge angle of them was very low. 7. There was no reduction failure in 27 hips which had metaphyseal-edge angle above 10 degrees. But 5 reduction failures were observed in 8 hips with below −11 degrees. 8. An avascular necrosis was observed in only one patient. In conclusion, the Pavlik harness proved to be a successful means in treating patients with congenital dislocation of hip under 7 months of age with particularly above −10 degrees in metaphyseal-edge angle.

Treatment of Congenital Dislocation of Hip by Open Reduction / 대한정형외과학회잡지

In the instance wherein concentric reduction cannot be achieved by closed method, open reduction is indicated. Prolonged and forceful attempts to reduce the refractory hips are not without risk to the circulation of the femoral head and open reduction is certainly a less traumatic way to obtain reduction in these hips. The authors performed clinical analysis in 30 patients with congenital dislocation of hip who were treated by open reduction between 1978 and 1987, The results are as follows :1. The results of treatment in 30 patients were acceptable in 22(73.3%), uncertain in 4(13. 3%), and unacceptable in 4 patients(13.3%). 2. Comparing the results depending on the presence of prior treatment or not, acceptable results were obtained in 86.4%(19 out of 22) of patients without prior treatment and in only 37.5%(3 out of 8) of patients with prior theatment by such as Pavlik harness and closed reduction. 3. The surgical approaches for open reduction were medial and anterior routes. The approach was selected depending on the age of patients and the severity of dislocation. The medial approach was used in patients under the age of 18 months. In mild degree of dislocation, the age limit of medial approach was extended to 24 months of age. The anterior approach was used in patients over 19 months of age.

Avascular Necrosis of the Femoral Head following Treatment of Congenital Dislocation of the Hip / 대한정형외과학회잡지

Avascular necrosis of the femoral head has been recognized as one of the most serious and frequent complications following the initial treatment of congenital dislocation of the hip. It is now well accepted that this particular complication is iatrogenic and may be avoided by careful and adequate treatment. The reported incidence of avascular necrosis is variable because of various methods of treatment and different diagnostic criteria. We retrospectively reviewed 130 patients(144 hips) with congenital dislocation of the hip, who were treated at Seoul National University Hospital during 10 year-period from January 1974 to December 1983, and found 13 patients (13 hips) with avascular necrosis of the femoral head. We analyed avascular necrosis following treatment of congenital dislocation of the with respect to various methods of treatment, possible causes, types of avascular necrosis, to radiological findings, and to functional results. 1. The incidence of avascular necrosis following treatment of congenital dislocation of the hip in our series was 9.0%(13/144 hips). 2. The average age of the patients with avascular necrosis was 3 years, the youngest being 4 months and the oldest being 10 years. The average follow-up period was 2 year and 2 months. 3. The incidence of avascular necrosis in the closed reduction series was higher in those between 6 months to 18 months with 10.5%, as compared to 7.1% in those 6 months and under 6.7% in those 18 months and over. In the open reduction series, the incidence increased as the age increased, being 5.9%, 12.4%, 15% in the groups 18 months to 3 years, 3 to 6 years, and 6 years and over, respectively. 4. The incidence of avascular necrosis in those who had priliminary traction was 8.3%, where as that in those who had not was 16.6%, being twice as much. 5. The incidence of avascular necrosis decreased as the traction time prolonged, being 9.0% in 7 days or less, 7.7% in 8 to 14 days, 7.1% in 15 to 21 days and nil in 22 days or more. 6. The incidence of avascular necrosis in the skin traction group was 5 times as much with 11.5%, as in the skeletal traction group with 2.2%, despite older age in the latter. 7. The incidence of avascular necrosis in the open reduction group was slightly higher with 9.5%, than in the closed reduction group with 8.6%. 8. All 6 cases of avascular necrosis following closed reduction occurred when Lorenz or frog-leg cast was applied initially after reduction despite attention to avoid extreme abduction. Avascular necrosis were not encountered in those who had Lange or human position cast as the initial form of immobilization. 9. In the closed reduction, avascular necrosis occurred 8.1% in those who had adductor tenotomy and 10.0% in those who had not. In the open reduction, avascular necrosis occurred 7.9% in those who had adductor tenotomy and 18.1% in those who had not, suggesting significant role of adductor tenotomy in the prevention of avascular necrosis. 10. Avascular necrosis was attributable to excessive abduction in 7 hips, to undue pressure of femoral head in one hip, to open reduction in 3 hips, to post-operative infection in one hip, and to non-union of subtrochanteric osteotomy in one hip. 11. Of the 13 hips, following roentgenograms were available in 11. According to the classification of Bucholz and Ogden, type I, II, III, IV were 7, 0, 3, and 1 hips, respectively. 12. Functional results of the 13 hips of avascular necrosis, according to Kalamchi and MacEwen's criteria, were Good, Fair, Poor in 9, 3, and 1 hips, respectively.