Objective:To investigate the accuracy and clinical utility of a newly designed acetabular bone defect classification system based on the ischial-gluteal pillar in assessing the severity of acetabular bone defects and guiding hip revision surgery.Methods:A retrospective analysis was conducted on 474 patients who underwent hip revision surgery for prosthetic loosening after total hip arthroplasty at our institution from January 2010 to December 2020, including 296 males and 178 females with a mean age of 70.4±8.9 years (range: 52-86 years). The accuracy of our classification system in guiding surgical procedures was evaluated by comparing preoperative defect classifications with intraoperative findings. Clinical outcomes were evaluated using preoperative and final follow-up Harris hip scores (HHS) and Oxford hip scores (OHS), as well as the incidence of complications.Results:Preoperative classifications included 143 Type I, 192 Type II (Type IIa: 86 cases, Type IIb: 59 cases, Type IIc: 47 cases), 93 Type III (Type IIIa: 54 cases, Type IIIb: 27 cases, Type IIIc: 12 cases), and 46 Type IV cases (Type IVa: 32 cases, Type IVb: 9 cases, Type IVc: 5 cases). Compared with intraoperative findings, classification accuracy was 99.3% for Type I (1 errors), 98.4% for Type II (3 errors), 97.8% for Type III (2 errors), and 97.8% for Type IV (1 misclassified as Type III). The mean follow-up was 5.8±4.4 years (range: 2-12 years). At final follow-up, mean HHS improved from 36.65±10.27 to 91.36±7.53, and mean OHS increased from 11.35±4.36 to 44.6±5.27 with significant difference ( P<0.001). Complications included one Type IV periprosthetic infection, one Type II hip dislocation, one Type I and two Type IV re-revisions (due to femoral loosening or graft resorption), one Type II and one Type III death unrelated to surgery, and one Type I postoperative thigh hematoma. No neurovascular injuries occurred. Conclusions:This novel 3D acetabular bone defect classification system, based on ischial-gluteal pillar integrity, provides accurate preoperative assessment and effectively guides surgical planning. Its application demonstrates favorable mid-term outcomes in hip revision surgery.

Objective:To investigate the accuracy and clinical utility of a newly designed acetabular bone defect classification system based on the ischial-gluteal pillar in assessing the severity of acetabular bone defects and guiding hip revision surgery.Methods:A retrospective analysis was conducted on 474 patients who underwent hip revision surgery for prosthetic loosening after total hip arthroplasty at our institution from January 2010 to December 2020, including 296 males and 178 females with a mean age of 70.4±8.9 years (range: 52-86 years). The accuracy of our classification system in guiding surgical procedures was evaluated by comparing preoperative defect classifications with intraoperative findings. Clinical outcomes were evaluated using preoperative and final follow-up Harris hip scores (HHS) and Oxford hip scores (OHS), as well as the incidence of complications.Results:Preoperative classifications included 143 Type I, 192 Type II (Type IIa: 86 cases, Type IIb: 59 cases, Type IIc: 47 cases), 93 Type III (Type IIIa: 54 cases, Type IIIb: 27 cases, Type IIIc: 12 cases), and 46 Type IV cases (Type IVa: 32 cases, Type IVb: 9 cases, Type IVc: 5 cases). Compared with intraoperative findings, classification accuracy was 99.3% for Type I (1 errors), 98.4% for Type II (3 errors), 97.8% for Type III (2 errors), and 97.8% for Type IV (1 misclassified as Type III). The mean follow-up was 5.8±4.4 years (range: 2-12 years). At final follow-up, mean HHS improved from 36.65±10.27 to 91.36±7.53, and mean OHS increased from 11.35±4.36 to 44.6±5.27 with significant difference ( P<0.001). Complications included one Type IV periprosthetic infection, one Type II hip dislocation, one Type I and two Type IV re-revisions (due to femoral loosening or graft resorption), one Type II and one Type III death unrelated to surgery, and one Type I postoperative thigh hematoma. No neurovascular injuries occurred. Conclusions:This novel 3D acetabular bone defect classification system, based on ischial-gluteal pillar integrity, provides accurate preoperative assessment and effectively guides surgical planning. Its application demonstrates favorable mid-term outcomes in hip revision surgery.

Objective:To evaluate the accuracy of the domestic "Skywalker" surgical robot in implementing personalized lower limb alignment reconstruction scheme in total knee arthroplasty (TKA) and the short-term clinical outcome of robotic assisted TKA.Methods:From September 2020 to January 2021, the data of patients who received surgical robot assisted TKA in 5 clinical centers in China (Shanghai Ninth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Southwest Hospital affiliated to Third Military Medical University, The Affiliated Hospital of Qingdao University, The First Affiliated Hospital of Chongqing Medical University and Yantai Yuhuangding Hospital, and Shanghai Ninth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine was the group leader) were prospectively collected and retrospectively analyzed. There were 24 males and 82 females with an average age of 67.6±7.3 years, (range 45-80 years); Average body mass index 26.42±4.31 kg/m 2, all the operation were performed by "Skywalker" surgical robot system according to preoperative design based on CT. The operation time, intraoperative blood loss, hospitalization days and postoperative complications were recorded, and the imaging indexes including hip-knee-ankle (HKA), lateral distal angle of femur (LDFA) and medial proximal angle of tibia (MPTA) measured before and after the operation, implant model indexes (preoperative planning implant model and postoperative implant model) and short-term clinical efficacy indexes [Western Ontario and McMaster Universities (WOMAC) osteoarthritis index] pain score, stiffness score, joint function score, total score and SF-12 score before and 3 months after the operation) were compared. Results:The average follow-up period was 109.60±9.80 d, (range 95-143 d). The average operation time of 106 patients was 105.30±23.22 min; The average intraoperative blood loss was 141.70±58.33 ml; The average length of hospitalization was 5.82±2.80 d. One patient had ischemic stroke after operation, and one patient had abnormal liver function after operation. According to the judgment of the investigator, all of them were not related to the operation. The actual angle error is the difference between the preoperative planning angle and the postoperative measurement angle. The absolute error of 99.1% (105/106) of the HKA angle was within 3°, 90.8% (69/76) of LDFA, 98.7% (75/76) of the MPTA. In 45 patients in one center where data were available, the actual implant models used in all patients were consistent with the preoperative planning size, and there were only differences in version selection such as Asian condyle. WOMAC pain score, joint function score, total score was improved from 7.34±2.85, 25.10±9.85, 34.75±13.02 to 3.34±2.66, 14.68±9.64, 18.66±13.49 before and after operation, respectively, which were statistically significant ( P<0.001) and SF-12 physiological score and psychological score were improved form 27.24±6.42, 30.68±8.26 to 38.83±5.74, 39.36±7.85 before and after operation, respectively, which were statistically significant ( t=7.33, P<0.001; t=4.53, P=0.043). Conclusion:Domestic surgical robot system "Skywalker" can assist the surgeon to achieve accurate and personalized reconstruction of lower limb alignment and achieve satisfactory short-term clinical outcomes. The long-term clinical outcomes of personalized reconstruction and survival rate of implant still need to be further studied.