Objective To investigate the effectiveness and the advantage of fixation with percutaneous cannulated screws assisted by robot navigation in the treatment of femoral neck fractures by comparing with the conventional surgery. Methods Between January 2013 and December 2014, 20 patients with femoral neck fracture were treated by internal fixation with percutaneous cannulated screws assisted by robot navigation (navigation group), another 18 patients undergoing conventional surgery with manual positioning were chosen as the control group. There was no significant difference in gender, age, cause of injury, the injury side, time from injury to operation, and the classification of fractures between 2 groups (P > 0.05). The operation time, X-ray fluoroscopy time, blood loss, frequency of guide pin insertion, and healing time were recorded. At 1 week after operation, the parallel degree of screws was measured on the anteroposterior and lateral X-ray films; the Harris score was used to evaluate the hip function. Results All incisions of 2 groups healed by first intention after operation. There was no significant difference in operation time between 2 groups (t= -1.139, P=0.262). The blood loss, frequency of guide pin insertion, and X-ray fluoroscopy time of navigation group were significantly less than those of control group (P < 0.05). There were 2 screws penetrating into the joint cavity in control group. The patients were followed up 12-24 months with an average of 18 months. The navigation group got significantly better parallel degree of screws than control group on the anteroposterior and lateral X-ray films (t=25.021, P=0.000; t=18.659, P=0.000). Fractures healed in all patients of navigation group (100%), and the healing time was (21.8±2.8) weeks; fracture healed in 16 patients of control group (88.9%), and the healing time was (24.0 ± 3.7) weeks. There was no significant difference in healing rate and healing time between 2 groups (χ2=2.346, P=0.126; t=1.990, P=0.055). The Harris score of navigation group (87.1±3.7) was significantly higher than that of control group (79.3±4.7) at last follow-up (t= -5.689, P=0.000). Conclusion Cannulated screw fixation assisted by robot navigation is a good method to treat femoral neck fractures, which has the advantages of more accurate positioning, better hip function recovery, less surgical trauma, and shorter X-ray exposure time.
ObjectiveTo investigate the application value of acetabular centralization technology for correction of leg-length inequality in total hip arthroplasty (THA). MethodsBetween June 2001 and January 2012, 147 cases of abnormal acetabular center were treated. Of them, 68 cases underwent routine THA (control group), and 79 cases underwent acetabular reconstruction by fossae ovalis oriented centralized technology in THA (test group). There was no significant difference in gender, age, side, pathogeny, acetabular rotation center indexs, difference of relative and absolute leg-length, and Harris score between 2 groups before operation (P>0.05). The hip joint function was evaluated by Harris score; the difference of relative leg-length was measured by tape; the difference of absolute leg-length and the horizontal and vertical distances of actual and true rotation center were also measured on the X-ray films by software. ResultsThe patients were followed up 8-26 months (mean, 8.3 months) in the test group, and 6-33 months (mean, 9.7 months) in the control group. Sciatic nerve injury occurred in 2 cases (1 in each group, respectively), lower extremity deep venous thrombosis in 7 cases (3 in test group and 4 in control group), and hip joint dislocation in 2 cases (control group); the other patients had no related complications. The difference of relative leg-length and Harris score in test group were significantly better than in control group (P<0.05), and significant difference was also found when compared with preoperative one in 2 groups (P<0.05). The horizontal and vertical distances of actual and the true rotation center in test group was significantly better than those in control group at immediate after operation on the X-ray films (P<0.05); and significant differences were also found when compared with preoperative ones in 2 groups (P<0.05). At 6 months after operation, the absolute leg-length difference in test group was significantly better than that in control group (P<0.05); and significant difference was also found when compared with preoperative one in 2 groups (P<0.05). ConclusionThe fossae ovalis oriented acetabular centralized technology in THA can significantly correct abnormal hip center of rotation, thus reduce the relative and absolute leg-length inequality and improve the life quality of the patients.