influence of body mass index and hip anatomy on direct anterior approach total hip replacement

Objective: To investigate the influence of body mass index [BMI] and hip anatomy on direct anterior approach [DAA] total hip replacement

Subjects and Methods: The study is a retrospective analysis of 124 cases of DAA total hip replacement from 2009 to 2012. The BMI, the ratio of the greater trochanter [GT] and anterior superior iliac spine [ASIS] bilaterally [GT/ASIS], and the vertical distance between the ASIS and GT [AGVD] were obtained from medical records. All cases were categorized into three groups [43, 49, and 32 cases in each group, respectively] based on BMI [BMI <18.5, BMI 18.5-25, and BMI >25] or divided into two groups based on GT/ASIS [ 1.17] or AGVD [ 86 mm]. Operating time, intraoperative bleeding, and surgical complications were compared between different groups

Results: A longer average operating time, more intraoperative bleeding, and a higher rate of complications were observed in the group with the highest BMI. The complications included a case of intraoperative femur fracture, a wound hematoma, and a lateral femoral cutaneous nerve injury. The group with higher GT/ASIS had a shorter average operating time, less bleeding, and a lower complication rate than the group with lower GT/ASIS. Moreover, the group with higher AGVD showed a shorter average operating time, less bleeding, and a lower complication rate compared with the group with lower AGVD

Conclusion: Our study suggests that lower BMI and larger GT/ASIS and AGVD are associated with a shorter operating time, less bleeding, and a lower complication rate in DAA total hip replacement. These findings are valuable for clinicians to make the appropriate choice of surgery types for different individuals

The treatment of periprosthetic femur fracture after hip arthroplasty / 中国基层医药

Objective To explore the treatment methods of periprosthetic femur fracture after hip arthroplasty.Methods 9 patiens with periprosthetic femur fracture after hip arthroplasty were selected.According to Vancouver classification,there were 1 case in A type,5 cases in B1 type,2 cases in B2 type,1 case in C type.One case were treated by nonoperative method and the other 8 cases were treated by operative method,including 5 cases treated by memory alloy embracing fixator and internal fixation,3 cases treated by long stem prosthetic replacement and iliac bone graft.Results 8 cases were followed up for 8 to 21 months,average 14.2 months.All fractures were united well with good alignment and internal fixation failure except one prosthesis loosing was observed.Conclusion For periprosthetic femur fracture after hip arthroplasty,Vancouver classification methods include the location and stability of the fracture,prosthesis loosening,and the femur in bone mass is importance to the clinical treatment.As to A type fracture,prosthesis is stable,and the conservative treatment can be choosed.As to B1 and B2 type fracture,the aggressive surgical treatment can be choosed based on patients' general condition.If prosthesis loosening after artificial hip arthroplasty,the patients should treated with long stem prosthetic replacement.

Total hip arthroplasty for acetabular protrusion / 中国矫形外科杂志

[Objective]To discuss the outcome of acetabular protrusion after total hip arthroplasty. [Method]Fifteen patients(M=7,F=9) having painful acetabular protrusion received total hip arthroplasty with reinforcement of the acetabulum with bone grafts(autogenous or allogeneous bone).The results were reported at 1~4 years(mean,3 years) of follow-up.Of the 15 cases,5 were mild protrusion and 10 were moderate protrusion.The Harris hip-rating and radiographs were taken pre-and postoperatively. [Result]The average Harris hip-rating was improved from 45 points(range,39~60 points) preoperatively to 85 points(range,70~100 points) postoperatively.The average preoperative protrusion of the femoral head medial to the Kohler line was 8.8 mm(6~18 mm).The average postoperative placement of the prosthetic femoral head was 10 mm(6~13 mm) lateral to the Kohler line.None acetabulum prothesis failure or bone grafts absorption was seen.The grafts were well incorporated on radiograms in all patients one year after operation by radiographs. [Conclusion]Good results can be obtained in hips with acetabular protrusion after reconstructed with autogeneous or allogeneous bone grafting and total hip arthroplasty.

Changes of bone mineral density of the proximal femur in patients with revision total hip arthroplasty / 中国矫形外科杂志

[Objective]To understand the changes of periprosthetic bone mineral density(BMD) of the proximal femur in patients with failed hip arthroplasty by measuring with dual energy X-ray absorptiometry(DEXA). [Method]Periprosthetic BMD was determined in 9 patients with revision total hip arthroplasty by dual energy X-ray absorptiometry(DEXA),defining regions of interest according to Gruen(1~7),and comparing the operation side with the nonoperation side.Clinic results of the cases were evaluated according to Harris Hip Score(HHS).[Result]The mean HHS was 61 points in 9 patients at this follow-up examination.There was a significant decrease(8.9%~27.6 %) in BMD in every Gruen zone as compared with the nonoperation side.[Conclusion]The bone loss in the proximal femur in patients with failed hip arthroplasty is significant,and the pattern of bone loss around failed hip arthroplasty may be different from the typical remodeling seen after successful hip arthroplasty.