Objective To evaluate the technique and clinical results of the modular fluted tapered stems for treating periprosthetic femoral fractures in revision hip arthroplasty.Methods From August 2007 to February 2014,fourteen patients (14hips) with periprosthetic femoral fractures underwent revision hip arthroplasty with modular fluted tapered stem.A retrospective analysis was performed involving all patients who were followed-up more than 2 years.The subjects consisted of 4 males and 10 females with mean age of 73.4±6.6 years (range,62-82 years) at the time of revision.All patients were unilateral with 8 left hips and 6 right hips.The status of primary arthroplasty was bipolar hemiarthroplasty in 3 patients and total hip arthroplasty in 11 patients.Nine cases were with cemented stems,5 cases with uncemented stems.The interval from primary hip arthroplasty to revision surgery ranged from 40 to 163 months,with an average of 120.9±31.9 months.Eight cases with Vancouver type B3 periprosthetic femoral fracture were found preoperatively,6 cases with aseptic loosening and bone deficiency occurred periprosthetic femoral fracture during the operation.Based on the Paprosky classification system for femoral bone deficiency:type ⅢA in 8 hips,type ⅢB in 5 hips,type Ⅳ in 1 hip.Both the femoral and the acetabular components were revised in 9 patients.All femoral fractures were treated with cable fixation,and the cortical allograft struts were used to augment femoral bone stock in 7 patients.The patients were followed up at 6 weeks,3 months,6 months,9 months,12 months and annually thereafter.Harris Hip Score System and radiographic examination was used to evaluate the clinical results,including fracture union,implant stability,bone stock,hip joint function and postoperative complications.Results The mean duration of follow-up was 62.1 ±22.2 months (range,30-96 months).The mean times of fracture union were 6.2±2.5 months (range,3-12 months).The Harris Hip Score improved from 29.6± 10.3 preoperatively to 86.3±4.2 postoperatively (t=-21.6,P=0.00).Thirteen cases (93％,13/14) had the stem subsidence of 4.9±2.5 mm (range,0-9 mm).Thirteen cases (93％,13/14) were presented with femoral bony restoration.Two cases showed incorporation of the allograft in 7 patients.One patient developed deep venous thrombosis of lower limbs,and one suffered from subcutaneous hematomas after surgery.There was no infection,aseptic loosening,dislocation or periprosthetic fracture complications at the followup.Conclusion The short-medium term results of the modular fluted tapered prosthesis applied in periprosthetic femoral fractures are encouraging in revision hip arthroplasty.The present technology can provide reliable primary stability and can tolerate minimal subsidence postoperatively.

Objective To analyze the risk factors of periprosthetic acetabular fracture in total hip arthroplasty (THA) and to discuss the prevention and management.Methods A total of 1 023 patients (1 168 hips) undergoing THA were retrospectively analyzed between January 2012 and June 2015.There were 421 males (507 hips) and 602 females (661 hips),aged from 23 to 96 years with mean age of 64.2± 15.0 years.Primary total hip arthroplasty was conducted in 1 053 hips,while revision surgery was conducted in 115 hips.The reasons of periprosthetic acetabular fracture were summarized.Age,gender,BMI,primary disease,left or right sides,surgical approach,osteoporosis,prosthetic type,the coverage rate of acetabulum-bone,and the amount of surgical operation annually were compared between non-fracture and fracture.Risk factors associated with the fracture were analyzed using chi square test followed by a multivariate logistic regression.Furthermore,revision surgery was compared with primary THA using chi square test.Results The incidence of intraoperative periprosthetic acetabular fractures was 2.8％ (33/1 168).The incidence of fracture was higher in revision surgery than that in primary THA (6.1％ vs.2.5％).Multivariate logistic regression showed that primary disease (developmental dysplasia of the hip and rheumatoid arthritis),osteoporosis,uncemented acetabular cup,the high-er coverage rate of acetabulum-bone,and the less amount of surgical operation annually were prone to appear periprosthetic acetabular fracture in primary THA.Among the 33 patients with acetabular fractures,13 cases (39.4％,13/33) were found intraoperatively and 20 cases (60.6％,20/33) postoperatively.Acetabular wall fractures were in 26 (78.8％,26/33),column fractures in 2 (6.1％,2/33),transverse fractures in 2 (6.1％,2/33) and quadrilateral surface fractures with prosthetic central dislocation in 3 (9.1％,3/33).Seven cases of 26 stable fractures and 6 cases of 7 unstable fractures were found intraoperatively.Acetabular wall fractures were fixed by additional augmentation screws or accepted no special treatment,and column fractures were fixed with plate.One quadrilateral surface fracture was accepted revision surgery using Jumbo cup,2 quadrilateral surface fractures and 2 transverse fractures with reconstruction cage.The patients were followed up for 42.3±13.7 months (range 29-60 months).The Harris hip score was 83.3±6.6 (range 72-94) at last follow-up.No complication,such as hip dislocation,osteolysis,and prosthetic loosening was reported.Conclusion Most of periprosthetic acetabular fiactures are wall fractures which could not endanger the periprosthetic stability.The detection rate of acetabular stable fracture is lower than that of unstable fracture in operation.Primary disease (developmental dysplasia of the hip and rheumatoid arthritis),osteoporosis,uncemented acetabular cup,the higher coverage rate of aeetabulum-bone,the less amount of surgical operation annually are the intraoperative risk factors which closely related to acetabular fractures of primary THA.The risk of intraoperative periprosthetic acetabular fractures in revision THA is higher than that in primary THA.