BACKGROUND:Artificial intelligence planning system can automatically establish a three-dimensional model and generate planning schemes,but its accuracy in predicting the prosthesis size has not been fully verified. OBJECTIVE:To investigate the accuracy of artificial intelligence planning system in predicting prosthesis size before total hip arthroplasty and its influence on clinical prognosis,and further analyze the risk factors affecting the accuracy of planning. METHODS:Clinical data of patients with unilateral initial total hip arthroplasty who were admitted to the Department of Orthopedics of Affiliated Hospital of Xuzhou Medical University from January 2021 to June 2022 were prospectively collected.The patients were randomly divided into the artificial intelligence planning system group(n=80)and the conventional template group(n=79).Intraoperative use of prostheses and preoperative planning of prosthesis matching were compared between the two groups.Postoperative follow-up Harris scores and the occurrence of complications such as leg length discrepancy,dislocation and prosthesis loosening were recorded in both groups.The effects of demographic indicators,preoperative diagnosis,and Dorr typing on the accuracy of femoral stem planning were explored using univariate and multivariate Logistic regression analyses. RESULTS AND CONCLUSION:(1)The prediction of the prosthesis size on the acetabular side and femoral side was 50%(40/80)and 55%(44/80)in the artificial intelligence planning system group,compared to 34%(27/79)and 37%(29/79)in the conventional template group,with statistically significant differences(P＜0.05).(2)The artificial intelligence planning system group had an accuracy rate within one size difference for the acetabular and femoral side prostheses of 91%(73/80)and 86%(69/80),compared to 82%(65/79)and 72%(58/79)in the conventional template group,with differences statistically different only on the femoral side(P＜0.05).(3)No dislocation or prosthesis loosening occurred in the two groups during postoperative follow-up.The difference in lower limb length between the artificial intelligence planning system and conventional template groups was(3.56±2.32)mm and(3.52±2.41)mm.At the last follow-up,the Harris scores of the artificial intelligence planning system and conventional template groups were(92.74±3.08)and(91.81±3.52),respectively;there was no significant difference in the above differences(P＞0.05).(4)Univariate analysis results showed that preoperative diagnosis as developmental dysplasia of the hip and osteonecrosis of the femoral head,and Dorr type B and C femurs had a significant effect on the accuracy of predicted prosthesis size using an artificial intelligence planning system(P＜0.05).(5)Multivariate logistic regression analysis showed that preoperative diagnosis of developmental dysplasia of the hip(OR=18.233,95%CI:2.662-124.888)was an independent risk factor for the prediction of femoral stem size by artificial intelligence planning system.(6)The artificial intelligence planning system has a higher accuracy in predicting prosthetic size than traditional two-dimensional templates,and there is not a significant difference in the risk of postoperative complications or joint function.The accuracy of the artificial intelligence planning system in patients with developmental dysplasia of the hip was low due to anatomical deformities and acetabular anatomical position reconstruction.

Objective:To investigate the effects of acetabular cup positions on the acetabular side stress in hip dysplasia after total hip arthroplasty (THA) using finite element analysis.Methods:Data were obtained from a 36-year-old female patient with developmental dysplasia of the hip. Three-dimensional finite element models were established for different acetabular cup positions using finite element analysis. Each model was categorized based on the center of rotation into four groups: anatomical rotation center, high rotation center, lateralized rotation center, superior-lateral rotation center. ANSYS software applied loads to the model to simulate the stress around the acetabulum in standing (588 N vertical stress) and walking conditions ( X=325 N, Y=-195 N, Z=1 462.5 N). Quantitative analyses of the relative displacement and stress at the acetabular-bone interface were conducted for each region under the two different loading conditions in all eight models. Results:In the standing position with a cup coverage of 90%, the relative displacement at the acetabular-bone interface was: 45.16 μm for the anatomical rotation center group, 47.57 μm for the high rotation center group, 77.27 μm for the lateralized rotation center group, and 96.13 μm for the superior-lateral rotation center group. Acetabular stress values were 9.07 MPa for the anatomical rotation center group, 11.23 MPa for the high rotation center group, 10.88 MPa for the lateralized rotation center group, and 17.75 MPa for the superior-lateral rotation center group. With a cup coverage of 70%, the relative displacements were 64.15, 65.71, 104.10, and 144.53 μm for the respective groups. The corresponding stresses were 9.30, 11.31, 13.98, and 21.45 MPa. In the walking state with a cup coverage of 90%, the relative displacements at the acetabular-bone interface were 189.67 μm for the anatomical rotation center group, 173.55 μm for the high rotation center group 311.03 μm for the lateralized rotation center group, and 572.93 μm for the superior-lateral rotation center group. The stresses were 39.92, 37.33, 47.92, and 71.94 MPa, respectively. With a cup coverage of 70%, the relative displacements were 239.09 μm for the anatomical rotation center group, 248.83 μm for the high rotation center group, 381.84 μm for the lateralized rotation center group, and 1105.90 μm for the superior-lateral rotation center group. The corresponding stresses were 40.62, 58.42, 56.26, and 3,606.30 MPa.Conclusion:With cup coverage at 70% and 90%, the high rotation center and anatomical rotation center exhibited lower and less frequent relative displacements at the acetabular-bone contact surface.

Objective:To investigate the difference in the efficacy of extended trochanteric osteotomy (ETO) and subtrochanteric shortening osteotomy (SSO) in total hip arthroplasty (THA) for Crowe type IV developmental dysplasia of the hip (DDH).Methods:Forty patients (51 hips) who underwent primary THA for Crowe type IV DDH from April 2012 to August 2020 at the First Affiliated Hospital of Soochow University and the Affiliated Hospital of Xuzhou Medical University were retrospectively analyzed. The patients were classified into ETO (extended greater trochanteric osteotomy) group and SSO(subtrochanteric shortening osteotomy) group. There were 12 patients (14 hips) in the ETO group, with 3 males and 9 females, aged 49.9±16.7 years old (range, 22-75 years old) and 28 patients (37 hips) in the SSO group, with 7 males and 21 females, aged 50.3±14.0 years (range, 22-76 years). In both groups, Harris hip score (HHS), leg length discrepancy, limp, Trendelenburg sign were used to evaluate the functional results and anteroposterior radiographs of the pelvis were taken at each follow-up to assess bone healing at the osteotomy site, periprosthetic osteolysis, bone ingrowth and periprosthetic loosening. Complications were recorded and analyzed.Results:All 51 hips were followed up for at least 24 months. The operative time and total blood loss was 116.8±14.2 vs. 128.3±19.2 min and 650.8±191.4 vs. 808.3±151.3 ml in the ETO group and the SSO group with significant difference ( t=2.04, P=0.047; t=3.08, P=0.003) respectively. At the follow-up of 24 months the HHS of ETO and SSO groups were 94.8±6.3 vs. 93.9±4.9 points and the leg length discrepancy was 4.6±2.2 vs. 5.2±3.0 mm. The positive rate of Trendelenburg's sign was 7% vs. 16% and the incidence of limp was 17% vs. 29% in the ETO group and the SSO group with no significant difference ( t=0.54, P=0.591; t=0.68, P=0.499; P=0.657; P=0.693). The length of femoral shortening in the ETO group and SSO group was 30.8±4.1 vs 35.3±7.9 mm with significant difference ( t=2.02, P=0.049). Time for bone healing at the osteotomy site was 5.8±1.5 vs. 6.0±1.4 months and the incidence of intraoperative femoral fractures was 36% and vs. 65% with no significant difference ( t=0.45, P=0.657; χ 2=3.52, P=0.061). Bone in-growth (or bone on-growth) fixation was obtained for all acetabular and femoral prostheses, with no hips of prosthesis displacement, periprosthetic osteolysis, or dislocation. Conclusion:Total hip arthroplasty for Crowe type IV DDH can achieve satisfactory clinical efficacy with similar functional recovery and rate of complication in extended trochanteric osteotomy and subtrochanteric shortening osteotomy. However, the extended greater trochanter osteotomy can reduce the operation time, blood loss and length of femoral shortening.

Objective: To investigate the effects of acetabular coverage on the initial stability of the cup during total hip arthroplasty in developmental dysplasia of hip. Methods: There were 50 fourth-generation synthetic hemi-pelvises. The different cup coverage rate (100% group, 70% group, 60% group, 50% group, 40% group) was created in pelvis with 10 specimens per group. The synthetic hemi-pelvis was fixed rigidly to a customized fixture which was placed on the testing table of the material testing machine. Pull-out and torque test were conducted by computer-control in torsion testing machine. Results: In the acetabular cup pull-out test, the average pull-out force for mode of failure in 100%, 70%, 60%, 50%, and 40% group was 1 560.4±438.7, 1 467.2±349.8, 1 137.8±427.4, 737.4±134.8, 506.6±119.0 N, respectively. The pull-out force was reduced gradually. The pull-out force in 100% group was significantly higher than that in 50% (P=0.004) and 40% (P=0.001) group. The pull-out force in 70% group was significantly higher than that in 50% group (P=0.002) and 40% group (P=0.000). The force in 40% group was significantly lower than that in 60% group (P=0.013) and 50% group (P=0.021). In the acetabular cup torque test, the average torque for mode of failure in 100%, 70%, 60%, 50%, and 40% group was 28.0±3.7, 17.0±2.2, 9.4±1.1, 7.6±1.1, 6.4±1.1 N·m, respectively. The torque was reduced gradually. The torque in 100% group was significantly higher than that in other groups (P<0.05). There was no significant difference between 50% and 40% group (P>0.05). The torque in other groups were similar (P>0.05). Conclusion The present biomechanical study showed that different acetabular cup coverage rate affected the initial stability of the cup. The highest initial stability was observed in the cup with a 100% of cup coverage rate. The cup could not obtain 100% coverage when with acetabular rim defect. We should try our best to make the cup coverage reach to 70%. The 70% coverage rate has sufficient initial stability to meet daily activities without increasing the cup loosening rate.

Objective To evaluate the clinical value of 3D printed modeling used to assist internal fixation for pelvic fractures.Methods The databases,Pubmed,EMBase,Cochrane library,CNKI,Wanfang and VIP,from initiation till August 2018,were searched for the controlled studies comparing surgery assisted by 3D printed modeling and conventional surgery in the treatment of pelvic fractures.The 2 groups were compared in terms of surgical time,blood loss,Matta score for reduction,Majeed score for functional recovery and complications.This meta-analysis was performed using software RevMan 5.3.Results A total of 6 relative controlled studies were included for this analysis involving 513 patients.There were 221 cases in the 3D printed modeling group and 292 ones in the conventional group.Our Meta-analysis showed that there were significant differences between the 2 groups in surgical time (MD =-48.11,95％ CI:-74.16 ～-22.06,P ＜0.05),blood loss (MD=-250.63,95％ CI:-337.42～-163.84,P ＜0.05) and Matta score for reduction (OR =1.85,95％ CI:1.07 ～ 3.20,P =0.03),favoring the 3D printed modeling group.No statistically significant difference was found between the 2 group in the rate of complications (OR =0.61,95％ CI:0.32 ～ 1.17,P =0.14).Conclusion Assistance with 3D printed modeling may help the surgery for pelvic fractures to shorten surgery time,decrease blood loss and improve reduction quality.

Objective To compare the clinical efficacy and biomechanical property between unilateral fixator (UF) and Taylor fixator (TF) for treating Gustilo Ⅱ tibiofibula fracture. Methods In this retrospective study ,86 patients with open tibiofibula fracture admitted from January 2012 to August 2015 were divided into an UF group (n= 49) or a TF group (n= 37) according to fixing method ,and their clinical efficacy and biomechanical property were compared. Providing the finite element model was fully proved effective ,the axial stiffness ,bending stiffness and torsional stiffness of UF and TF were tested by this model.Additionally ,the torsional stiffness was measured at every 10° revolving around the model. Results The operation time was shorter in UF group (43.2 ± 11.7) min than in TF group (63.6 ± 9.8) min (P=0.027) ,and blood loss was less in the UF group (32.1 ± 13.8) ml than in TF group (57.6 ± 23.1) ml (P<0.001).All the patients were followed up for 8-31 months (mean:13.8 months). The healing time was shorter in the UF group (4.6 ± 1.7) months thanintheTFgroup(5.7 ±2.1)months(P=0.039).Thecomplicationrateswere4.5％ (9/201)in the UF group ,which was significantly less than that in the TF group (12.0％ ,14/117) (P<0.05) .For biomechanical property ,the axial ,bending and torsional stiffnesses were higher in the UF group [(341.47 N/m ,80 Nm/deg ,and (210-430) N/m ,respectively]than in the TF group[226.83 N/m ,72 Nm/deg ,and (242-287 ) N/m ,respectively ]. Conclusions In the treatment of open tibiofibula fracture ,UF is easier to operate and has better agreement with the biomechanical property and better ability to resist a rotation and a compression ,which is obviously superior to TF.Besides ,UF is better than TF for fracture recovery.

Objective To assess the mid-or long-term clinical outcomes of the structural bone graft of superolateral acetabulum in total hip arthroplasty (THA) for developmental dysplasia of the hip (DDH).Methods Thirty-three patients with DDH (33 hips) were treated by THA with the structural bone graft of superolateral acetabulum technique between April 2002 and December 2011.There were 28 females and 5 males with the mean age at surgery 54.0±14.5 years (21-76 years).The degree of dislocation was graded preoperatively as Crowe Ⅱ in 12 patients,Crowe Ⅲ in 8 patients,and Crowe Ⅳ in 13 patients.The following outcomes were assessed,Harris hip score (HHS),the leg-length discrepancy,the height and horizontal distance of center of hip rotation,rate of cup coverage,the coverage ratio of bone graft,periprosthetic osteolysis,bone ingrowth,and cup loosening.Results The average follow-up was 9.3±3.3 years (5-15 years).The HHS improved from 40.9±13.7 preoperatively to 93.6±7.8 at the final follow-up (t=21.483,P=0.000).The leg-length discrepancy decreased from 24.2± 17.1 mm pre-operatively to 3.7±3.5 mm at postoperative 3 months (t=6.747,P=0.000).The height and horizontal distance of center of hip rotation decreased from preoperative 45.9±16.0 mm and 42.9±8.7 mm to postoperative 23.8±5.8 mm and 23.6±2.9 mm (t=7.460,P=0.000;t=12.090,P=0.000) at postoperative 3 days,respectively.The cup coverage and coverage ratio of bone graft was 100％ and 27.1％±6.9％,respectively.All grafts appeared to be incorporated without evidence of resorption and collapse.The mean time of incorporation was 7.6 ± 2.8 months.The coverage ratio of bone graft ＞25％ have a significantly long time of incorporation than that ＜25％ (9.4±2.3 months versus 6.3±2.4 months,t=5.357,P=0.000).At the final follow-up,all hips showed bone ingrowth fixation of the acetabular cup and stem.Five hips showed osteolysis,two hips in acetabular zone Ⅱ,three hips in femur zone Ⅰ and five hips in femur zone Ⅶ.The main complications were intraoperative femoral fractures (61％) without neurological damage,nonunion and dislocation.Conclusion The structural bone graft of superolateral acetabulum in THA for DDH can achieve satisfactory mid-or long-term outcomes.The superolateral acetabular deficiency can be reconstructed by bone graft.The bone graft coverage less than 25％ is conducive to fusion of bone graft and acetabular bone.However,intraoperative femoral fracture is common complication.

BACKGROUND: With the rapid development of surgical techniques, unicompartmental knee arthroplasty has become an issue of concern in the treatment of osteoarthritis, which has achieved significant progress inreducing trauma and rapid rehabilitation.OBJECTIVE: To summarize the development history, curative effect of unicompartmental knee arthroplasty, and the research progress of lateral unicompartmental knee arthroplasty aided with computer navigation or robot system, thus providing reference for further study on unicompartmental knee arthroplasty.METHODS: Web of Science, and PubMed databases were searched for the literatures published from January 1955 to April 2017 with the keywords of unicompartmental knee arthroplasty, osteoarthritis, unilateral compartment, lateral knee arthroplasty.RESULTS AND CONCLUSION: A total of 562 articles were retrieved, and finally 75 English literatures were enrolled according to the inclusion and exclusion criteria. With the continuous improvement of unicompartmental knee arthroplasty, it can retain the cruciate ligament and more bone mass. Notably, strict indications and reasonable postoperative functional exercise are essential for obtaining optimal effectiveness. At the same time, the development of computer navigation and robot-assisted technology has opened up a new horizon for the treatment of osteoarthritis,which makes the operation more accurate and minimally invasive. But the application still needs to be studied in depth.

Objective To evaluate the mid-and long-term clinic results of ceramic-on-ceramic joint in total hip arthroplasty (THA) in younger patients.Methods A retrospective review was made on 72 younger patients who had THA with ceramic-on-ceramic bearings due to femoral head necrosis or inborn hip dysplasia between March 2001 and March 2011.There were 32 females and 40 males,at a mean age of (35.2 ± 7.6)years (range,17-45 years).Patients were evaluated with Harris hip score and University of California,Los Angeles (UCLA) activity score.Radiological findings were recorded including component loosening,ostelysis,and ceramic bearing related complications.Results Duration of followup was (8.5 ±2.4) years (range,5-12 months).At the final follow-up,Harris hip score was increased to (93.8 ±4.3)points (range,85-100 points) compared to preoperative (46.1 ± 12.3) points (range,27-70 points) and UCLA activity score was increased to (7.1 ± 1.4)points (range,4-10 points) compared to preoperative (4.0 ± 1.2) points (range,2-6 points) (P ＜ 0.05).At the final follow-up,no osteolysis or prosthesis loosening occurred,but there were ceramic sandwich liner fractures in two patients (two hips),dislocation in one patient (one hip) and squeaking in one patient (one hip).After revision due to the ceramics break,the 8-year survival rate was 97％ (95％ CI91.9-100.0).Conclusion Ceramicon-ceramic joint in THA satisfies the activity demand in younger patients,with excellent mid-and longterm clinical results.

Objective To analyze the epidemiology,mechanisms of injury,type of fracture,clinical and radiological feature of acetabular fractures in patients aged 60 years and older.Methods Retrospectively analyzed the clinical data of patients with acetabular fractures between Janurary 1990 and December 2013 in Orthopaedic Department of the First Affiliated Hospital of Soochow University.According to certain inclusion and exclusion criteria,a total of 637 patients (637 hips) with acetabular fractures were included in the study.The patients were divided into 2 group acetabular fractures in elderly (≥60 years) and acetabular fractures in younger patients (＜ 60 years).Analysis of mechanism of injury,fracture pattern,the annual incidence of fracture,radiological features,associated injuries.Results 133 patients were ≥60 years and the remaining 504 were ＜ 60 years.We identified a significant increase in the incidence of elderly with acetabular fractures between 1990 and 2013 (6.7％ in 1990 vs.40.0％ in 2013).The incidence of associated injuries were significant lower in the elderly than younger (27.1％ vs.48.8％).The most common mechanism of injury in the elderly was a fall (36.1％),but this accounted for only 0.2％ of the younger with fractures.The incidence of anterior wall,anterior column,anterior and posterior hemitransverse were significant higher in the elderly than younger.The incidence of radiological features were significant higher in the elderly than younger,including quadrilateral plate fracture,Gull sign,anterior dislocation of hip,femoral head injury,comminuted posterior wall fracture and posterior wall marginal impaction,except posterior dislocation of hip which was significant lower in the elderly than younger.Conclusion There was an increasing trend of the proportion of elderly in acetabular fractures and the mean age of patients with fractures during the period of study.The older had a different incidence of associated injuries,mechanism of injury,fracture pattern,and radiological features compared with the younger.