Objective:To investigate the stability and feasibility of using absorbable screws during Bernese periacetabular osteotomy.Methods:A retrospective analysis was conducted on a 36 year-old woman diagnosed with developmental dysplasia of the hip, who had undergone Bernese periacetabular osteotomy. Finite element analysis was used to simulate the stability of the acetabulum under loads of 10%, 20%, 50%, and 100% of the patient's weight. The structural stiffness of the pelvis and the maximum equivalent stress on the absorbable screws were observed under different conditions, including whether the acetabular bone block and the ilium were in contact, whether 3 or 4 screws were used, and whether a graft (including fibular cortical bone and PEEK grafts) was used.Results:The structural stiffness of the pelvis fixed with four screws increased by 67%-94% compared to that with three screws. After using a graft, the structural stiffness of the pelvis increased by 50%-83%. As the load increased, the maximum equivalent stress on the screws also increased. When the acetabular bone block and the ilium had no contact, no graft was used, and only three screws were used for fixation, the maximum equivalent stress could reach 518.9 MPa, while this value dropped to 61% when four screws were used (318.7 MPa). When the acetabular bone block and the ilium were in contact, the maximum equivalent stress was about 12% of that when there was no contact, regardless of the number of screws used. When a cortical bone graft or a PEEK graft was used, the maximum equivalent stress could drop to 21%-26% of that without a graft. When the screw strength was 130 MPa, a load of 20% of body weight was applied, and only three screws were used without a graft, the equivalent stress could exceed the strength of the screw; if four screws were used, the equivalent stress was slightly higher than the strength of the screw when a load of 50% of body weight was applied. However, when a graft was used (either cortical bone or PEEK), even when a load of 100% of body weight was applied, the equivalent stress was slightly lower than the strength of the screw.Conclusion:Absorbable screws can provide sufficient stability for Bernese periacetabular osteotomy. The contact between the acetabular bone block and the ilium, an increase in the number of screws, and the use of grafts (cortical bone and PEEK grafts) can further improve stability. Therefore, absorbable screws have broad application prospects in Bernese periacetabular osteotomy.

Objective:To investigate the outcomes of periacetabular osteotomy (PAO) through modified Smith-Petersen or Bikini approach with an auxiliary posterolateral incision for developmental dysplasia of hip (DDH).Methods:85 patients (97 hips) who underwent PAO through modified Smith-Petersen or Bikini approach with auxiliary posterolateral incision for DDH in the 920th Hospital of Joint Logistics Support Force of Chinese People's Liberation Army or the Second Xiangya Hospital of Central South University from January 2016 to January 2021 were retrospectively analyzed. There were 70 females and 15 males, with an average age of 28.6±8.4 years (12-49). According to the Hartofilakidis classification, all patients were classified as type Ⅰ. There were 77 hips classified as Grade 0 and 20 hips classified as Grade 1 according to the T?nnis classification. The X-ray evaluation including the lateral central edge angle (LCEA), t?nnis angle (TNS) and anterior central edge angle (ACEA), visual analogue score (VAS) and modified Harries hip score (mHHS) were recorded preoperatively and during each postoperative follow-up. The cumulative sum (CUSUM) method was used to fit the learning curves of operation time.Results:All patients were followed-up with an average of 52.7±18.9 months (21 to 84). The average operative time and intraoperative blood loss were 95.9±28.2 min (65 to 215) and 414.7±97.0 ml (250 to 900), respectively. The learning curve of operation time was 10 cases. The average LCEA 32.39° (30.29°, 34.92°), TNS 3.14° (1.56°, 5.67°) and ACEA 31.55° (29.07°, 33.88°) were all significantly improved compared to preoperative values ( Z=-30.764, P<0.001; Z=30.595, P<0.001; Z=-38.134, P<0.001). The average VAS was reduced from 5.18±0.88 points preoperatively to 1.27±0.93 points postoperatively with significant difference ( t=51.231, P<0.001). The average mHHS was increased from 73.12±9.17 to 92.02±4.05 postoperatively with significant difference ( t=-26.902, P<0.001). No patients received total hip arthroplasty during the follow-up period. Conclusion:Bernese PAO through modified Smith-Petersen or Bikini approach with a small auxiliary posterolateral incision was not only a safe and effective method for the treatment of DDH but also shortened the learning curve and reduced difficulty of the surgery.

Objective:To investigate the effects of periacetabular osteotomy (PAO) in treating borderline developmental dysplasia of the hip (DDH).Methods:The patients with borderline DDH [lateral center-edge angle (LCEA): 18°-25°) who received PAO with follow-up duration for more than 2 years from January 2011 to January 2018 in our hospital were retrospectively analyzed. The patients in the control group were matched on a 1∶2 ratio based on gender, age, body mass index (BMI) and follow-up duration. There were 66 patients in the 0°≤LCEA<10° group and 66 patients in the 10°≤LCEA<18° group. The LCEA, anterior center-edge angle (ACEA), T?nnis angle, femoral head extrusion index, femoro-epiphyseal acetabular roof (FEAR) index, femoral anteversion angle, West Ontario and McMaster University (WOMAC) index and International Hip Outcome Tool (iHOT-12) were compared among the three groups before operation and the last follow-up.Results:In the preoperative 18°≤LCEA<25° group, three of 33 patients (9.1%) had LCEA, because the only imaging feature suggested acetabular dysplasia, while other parameters were evaluated within the normal range. There were 17 patients with ACEA <20° (51.5%), 24 patients (72.7%) with T?nnis angle >10°, 12 patients (36.4%) with ACEA <20° and T?nnis angle >10°. The positive rate of posterior wall signs in the 18°≤LCEA<25° group (72.7%) was lower than that in the 10°≤LCEA<18° group (77.3%) and the 0°≤LCEA<10° group (90.9%) with statistically significant difference (χ 2=6.417, P=0.040) at preoperation. The positive rate of cross sign (27.3%) and ischial spine sign (48.5%) in the 18°≤LCEA<25° group were higher than those in the 10°≤LCEA<18° group (10.6% and 18.2%, respectively, χ 2=7.002, P=0.030) and the 0°≤LCEA<10° groups (9.1% and 13.6%, respectively, χ 2=16.497, P<0.001). The FEAR index in the 18°≤LCEA<25° group (3.7±8.0) lower than that in the 10°≤LCEA<18° group (4.3±7.9) and the 0°≤LCEA<10° group (11.0±8.8) with significant difference ( F=12.703, P<0.001). In the 18°≤LCEA<25° group, postoperative LCEA increased from 20.4°±1.8° to 37.8°±7.1°, ACEA increased from 18.3°±7.8° to 36.3°±6.3°. T?nnis angle decreased from 12.7°±6.2° to -5.6°±9.2°, the femoral head extrusion index decreased from 22.9%±6.7% to 10.7%±12.2%, the WOMAC index decreased from 20.1±13.4 to 6.0±6.3, and the iHOT-12 score increased from 50.2±19.9 to 90.0±13.7. The above difference before and after surgery was statistically significant ( P<0.05). At the last follow-up, the WOMAC score in the 18°≤LCEA<25° group was 6.0±6.3, wich was less than 10°≤LCEA<18° group (9.3±9.6) and 0°≤LCEA<10° group (12.0±16.0) ( F=6.515, P=0.002). The iHOT-12 score in the 18°≤LCEA<25° group was 90.0±13.7, which was greater than 10°≤LCEA<18° group (77.7±17.3) and 0°≤LCEA<10° group (78.1±20.5) ( F=15.833, P<0.001). Conclusion:After 2 years follow-up, PAO significantly improved bone coverage of femoral head and hip function in patients with borderline DDH. Before surgery, we should pay attention to the comprehensive evaluation of different radiological parameters of the acetabulum, to make better preoperative planning.

Objective: To explore the impacts of the imaging positions on the sagittal tilt of the pelvis and the imaging parameters of the hip joint. Methods: From December 2015 to October 2016, a total of 78 female DDH patients (DDH group) who received Bernese periarticular osteotomy were enrolled, aged 28.41±9.91 years (range 18-49 years) with 135 hips. There were 21 cases on one side and 57 cases on both sides. Another 26 female volunteers without spinal and hip disease were enrolled as the control group, aged 23.54±5.58 years (range 18-49 years) with 52 hips. X-ray films of the anterior and posterior pelvis were performed in both groups. The pelvic sagittal tilt was evaluated by measurement (pubic symphysis to sacrococcygeal distance, PSSC), with lateral center-edge angle of Wiberg (LCEA), Tönnis angle (TA), and Sharp angle (angle of Sharp, SA) assessed the degree of hip dysplasia and assessed the horizontal positional relationship between the femoral head and the acetabulum using tear drop distance (TD). All data were measured twice by two measurers independently. The correlation between hip parameters and X-ray position was analyzed. Results: The average PSSC in the supine and standing positions of the control group were 53.73±16.22 mm and 36.45±14.21 mm, respectively with significant difference-17.28±8.07 mm (t=-10.913, P=0.000). The PSSC of the supine and standing positions of the DDH group were 56.76±13.54 mm and 48.62±15.44 mm, respectively with significant difference-8.13±13.02 mm (t=-5.516, P=0.000). The PSSC of the standing DDH group was larger than that in the control group. There was no significant difference in the PSSC between the two groups in the supine position. Furthermore, there were no significant difference in the supine and standing PSSC between the unilateral and bilateral DDH patients (P>0.05). In the control group, the hip in supine and standing position, LCEA averaged 30.33°±4.69° and 29.70°±3.83° (P>0.05), and TA averaged 4.05°±3.51° and 4.36°±3.07° (P>0.05), respectively. SA averaged 40.53°±4.34° and 41.79°±3.16° (P>0.05), and TD averaged 6.80±0.98 mm and 6.65±1.30 mm (P>0.05), respectively. In the DDH group, the hip in supine and standing positions, LCEA averaged 3.07°±12.07° and 1.69°±12.11° (P<0.05), and TA averaged 22.62°±9.31° and 23.82°±9.45° (P>0.05), respectively. SA averaged 48.01°±4.68° and 48.49°±4.74° (P>0.05), respectively, and TD averaged 10.51±3.51 mm and 10.93±4.23 mm (P>0.05), respectively. Conclusion From supine to standing, the pelvis backward is the main trend in sagittal plane. In standing, the pelvis of female DDH patients is forward contrast with normal women. There was no difference in pelvic tilt between unilateral and bilateral DDH patients. Female DDH patients from the supine to standing, hip coverage decreased, while the femoral head appeared horizontally outward. The hip joint of DDH patients is unstable.

Objective To report the short-term outcomes of the rotational osteotomy on the base of femoral neck in treating osteonecrosis of femoral head.Methods Ten patients (10 hips) with osteonecrosis of femoral head underwent the rotational osteotomy on the base of femoral neck between March 2014 and October 2016.There were 9 males and 1 female.The average age was 29.6 years,ranging from 18 to 42 years.There were 4 patients in right side and 6 in left side.The Association Research Circulation Osseous (ARCO) Stage was from ⅡB to ⅢC (2 cases of ⅡB,2 cases of ⅡC,1 case of ⅢA,1 case of ⅢB,4 cases of ⅢC).The following main procedures were involved in the treatment:surgical hip dislocation,the extension of retinacular soft-tissue flap to protect the main blood supply of the femoral head,anterior or posterior rotational (60°-90°) of femoral head after femoral neck osteotomy.We used three compress cannulated screws to fix the femoral neck osteotomy.The postoperative Harris hip scores (HHS),Western Ontario and McMaster College (WOMAC) score,pelvic A-P view and lateral hip view radiographic characteristics were analyzed to assess the short-term outcomes.Results The average follow-up duration was 16.3 months (7-36 months).No progressive femoral head collapse was observed in 6 patients at the last follow-up.The average post-operative intact ratio was 42.90％± 10.07％.The HHS improved from 80.00±14.93 to 86.83±6.11 (4 cases improved,1 case with no change and 1 case decreased slighdy).The WOMAC score decreased from 16.00±14.53 to 9.00±3.85 (1 cases increased,1 case with no change and 4 case decreased).The remaining 4 cases,however,had the progression of the femoral head collapse.The average post-operative intact ratio was 16.57％±6.57％.The HHS decreased from 77.75±14.66 to 60.75±17.54 (1 case improved slightly and 3 cases decreased).The WOMAC score increased from 12.75±5.06 to 22.50±8.81 (4 cases increased).Conclusion The rotational osteotomy on the base of femoral neck not only shifts the necrosis area away from weight-bearing region but also improves the post-operative intact ratio.Patients with ARCO stage ⅡB-ⅢB may achieve remission of symptoms and improvement of hip function by this surgical technique.However,for patients with ⅢC stage,we should conduct preoperative design to make sure whether the surgery is worth doing or not.Some patients may suffer from post-operative progression collapse of the femoral head.

Objective To investigate the clinical efficiency and safety of femoral head reduction osteotomy for young patients with coxa magna or coxa plana.Methods Between June 2012 and September 2015,the clinical characteristics of 12 patients (13 hips) with coxa magna or coxa plana who underwent femoral head reduction osteotomy were analyzed retrospectively.There were 6 males (7 hips) and 6 females (6 hips) with average age 18.1 years (range,10-25 years).The etiology of the femoral head deformity was multiple epiphyseal dysplasia in 6 hips and Legg-Calvé-Perthes sequela in 7 hips.The head reduction osteotomy was conducted through the surgical hip dislocation approach combined with extended retinacular soft-tissue flap extending technique.All patients underwent simultaneous periacetabular osteotomy and relative lengthening of the femoral neck,of which four also underwent proximal femur derotational osteotomy.All patients received the standardized rehabilitation procedures.The postoperative complications,gaits,the range of motion (ROM) of the hip,Harris hip scores,iHOT scores and VAS were analyzed postoperatively.In addition,the lateral center-edge (LCE) angle,sphericity index and coverage rate of femoral head were assessed as well.Results The average follow-up duration was 28.8 months (range,12-45 months).All patients achieved osteotomy healing of the femoral head and greater trochanter with average healing time 3.7 months (range,3-7 months).Nine of 12 patients had significant gaits improvement.The Harris hip scores (81.08± 12.36 vs.88.38 ± 8.96,t=2.41,P=0.033),iHOT score (51.90± 15.07 vs.67.69±8.70,t=3.63,P=0.003),LCE angle (-1.82°±16.57° vs.36.02°±7.72°,t=10.52,P=0.000),sphericity index of anteroposterior pelvic radiographs (71.08％± 10.32％ vs.81.22％±8.61％,t=7.17,P=0.000) and the coverage index (48.79％±11.85％ vs.87.46％± 10.44％,t=8.56,P=0.000) were all significantly improved when compared to those preoperatively.The VAS score (4.46± 2.37 vs.1.23±0.93,t=4.25,P=0.001) was significantly decreased when compared with that preoperatively.However,for the sphericity index of 65° false profile (78.96％± 10.39％ vs.80.36％±8.42％,t=0.411,P=0.688) and the average hip ROM (264.62°± 32.05° vs.255.00°±40.31°,t=0.89,P=0.391),they did not achieve statistical significant difference.One case of femoral head necrosis site was localized at the lateral-superior part of femoral head,and there was no progression after 3 years follow-up.Moreover,no revision or total hip arthroplasty were observed due to other complications (osteoarthritis,hip pain or non-union).Conclusion The femoral head reduction osteotomy can correct deformity,improve femoral head sphericity,relieve pain and improve gaits and hip function.This procedure leads to satisfied clinical outcomes for patients with coxa magna or coxa plana in early follow-up.

Developmental dislocation of the hip(DDH) is one of the most serious hip diseases. Patients with unilateral DDH are prone to secondary osteoarthritis, low back pain, gait disturbance and compensatory scoliosis because of the leg length discrepancy. Total hip arthroplasty(THA) is the highly effective treatment for patients with hip pain or dysfunction caused by unilateral DDH, thus decrease the demand for hip-preserving surgeries such as capsular arthroplasty which may postpone or avoid hip replacement. However, the failure rate of THA for young patients is high and the majority of young patients may require one or more revision arthroplasties throughout their lifetime. The basic principle of capsular arthroplasty is that the femoral head wrapped by capsule is placed into a newly reamed socket on the location of true acetabulum. Therefore, hip replacement for patients with previous capsular arthroplasty becomes easier and safer than primary THA. However, the early capsular arthroplasty have been abandoned due to the relatively high rates of femoral head necrosis and hip stiffness. Ganz modified the early procedure with the technique of surgical hip dislocation in 2012, and emphasized the importance of postoperative rehabilitation. The incidence of complication, therefore, decreased greatly due to the preservation of main blood supply of femoral head as well as the proper postoperative management. In order to improve the clinical outcomes of this modified procedure, the selection of indications and surgeons′ experience should also be taken into consideration.

OBJECTIVETo observe the distribution law and study the factors related to the femoral neck anteversion angle among the patients with developmental dysplasia of the hip of Hartofilakidis type I.

METHODSAmong the patients with hip dysplasia of Hartofilakidis type I who was admitted to Department of Orthopaedic Surgery, the First Affiliated Hospital of People's Liberation Army General Hospital from June 2010 to June 2013, a total of 340 hips (25 male and 161 female) were included in the study. The average age was 28.3 years, ranging from 13.5 to 49.9 years. The observation index included: femoral neck anteversion angle, lateral center-edge angle, acetabular index angle, lateral displacement of the femoral head, superior displacement of the femoral head, continuity of Shenton's line and Calve's line. The correlation between different factors was analyzed, and the factor closest to femoral neck anteversion angle was analyzed further by regression analysis.

RESULTSAmong the patients of developmental dysplasia of the hip of Hartofilakidis type I, the femoral neck anteversion angle increased, with an average of 28°±13°. Correlation and regression analysis showed significant negative correlation with treatment age (r=-0.158, P=0.003; t=-6.892, P=0.000); positive correlation with gender (r=0.332, P=0.000; t=-4.376, P=0.000); significant positive correlation with lateral displacement of the femoral head (r=0.092, P=0.000; t=3.766, P=0.000); significant negative correlation with central-edge angle (r=-0.122, P=0.024; t=2.031, P=0.043). The femoral neck anteversion angle showed correlation with acetabular index angle, continuity of Calve's line and superior displacement of the femoral head in correlation analysis, not in regression analysis, however, it did not show correlation with side and continuity of Shenton's line.

CONCLUSIONAmong the patients of developmental dysplasia of the hip of Hartofilakidis type I, the increasing of the femoral neck anteversion angle may not only lead to early onset and therefore early treatment of pain in the hip joint but also the lateral displacement of the femoral head that requires immediate medical attention.

Acetabulum ; Adolescent ; Adult ; Female ; Femur Head ; Femur Neck ; pathology ; Hip Dislocation, Congenital ; pathology ; surgery ; Hip Joint ; Humans ; Hyperplasia ; Male ; Middle Aged ; Orthopedic Procedures ; Orthopedics ; Regression Analysis ; Tomography, X-Ray Computed ; Young Adult

Objective To investigate the radiological characteristics and the relationships between the parameters by X?ray and direct magnetic resonance arthrography (dMRA) in non?completely dislocated dysplasia hips. Methods We retro?spectively reviewed patients (above 13 years old) with dysplasia hips from August 2009 to August 2012. These patients were classi?fied as Hartofilakidis typeⅠand typeⅡ. 188 patients (274 hips) involved 28 males (30 hips) and 160 females (244 hips), average aged 27.3 years (range 13-47 years). Standard pelvic A?P, bilateral 65° oblique X?rays, and dMRA were conducted in each pa?tient. Lateral central?edge angle (LCE), anterior central?edge angle (ACE), femoral neck?shaft angle (FNSA), and tonnis acetabu?lar index (AI) angle were measured based on the X?ray. The dysplasia hips were classified into 4 grades (GradeⅠ:CE 11°-20° , GradeⅡ:CE 1°-10°, GradeⅢ:CE-9°-0°, and GradeⅣ:CE≤-10°). Femoral neck anteversion angle (FNA), labral tear, labral inversion, and labral cyst was observed on dMRA films. Variance analysis and rank correlation were applied to find the relation?ship between CE grades and the relevant parameters by using SPSS 19.0. Results LCE has negative correlation with AI and grade of osteoarthritis, and has positive correlation with age, ACE. However, there was no relationship between FNSA and FNA. There was significantly different in Shenton's line, labral tear, labral inversion, cartilage lesion, among different grade of LCE. Conclusion LCE is an important parameter used in evaluating for dysplasia hips without complete dislocation. LCE can reflect age of onset, ACE, AI angle and degree of joint damages. Evaluation for the severity of non?completely dislocated dysplasia hips can be conducted according to grades of CE.

Objective To discuss the mid?to long?term results and possible prognostic factors of Bernese periacetabu?lar osteotomy for adolescents and young adults with developmental dysplasia of the hip. Methods Bernese periacetabular os?teotomy was performed on 162 patients (171 hips) with hip dysplasia from August 1997 to July 2009. Follow?up data was ac?quirable completely in 123 cases (137 hips), including 30 males (33 hips) and 93 females (104 hips). Age of surgery was 12-48 years (average 27.1 years). The X?ray radiographs and Harris scores were recorded preoperatively and at the last follow?up. The lateral center?edge angle (LCE), acetabular incline angle (AI), continuity of Shenton's line were also recorded. The grades of the hip osteoarthritis were classified by T?nnis classification. Insufficient corrections of osteotomy, excessive corrections of osteotomy, nonunion of the pubis, nerve injuries, and vascular injuries were recorded as complications. Results All the con?tactable cases was followed up again in June and July in 2014. Follow?up duration was 5-17 years (mean, 8.1 years). The LCE angle improved from 7.13° ± 8.86° preoperatively to 30.17° ± 14.98° at the final follow?up. The T?nnis acetabular incline angle decreased from 27.84° ± 12.85° preoperatively to 7.06° ± 10.58° at the final follow?up. The continuity of Shenton's line was in?tact in 106 cases postoperatively, compared with 87 cases preoperatively. Harris score improved from 83.34±9.82 preoperative?ly to 92.79±7.05 at the last follow?up. There was significant correlation between preoperative Harris score and Harris score at the last follow?up. Early complications were observed in 15 cases (15 hips), along with 17 cases (17 hips) of progressions of hip osteoarthritis. Survival rate of the hip at the last follow?up was 97.8%. Conclusion Bernese periacetabular osteotomies can significantly improve bone coverage and joint function of hip dysplasia patients with low rate of short?term complications. Further?more, there was little osteoarthritis progression observed, with good survival rate of the joint in mid?to long?term follow?up. Lower pre?operative Harris scores and higher pre?operative T?nnis classifications are important prognostic factors for post?operative pain.