Computed tomographic evaluation of component position on dislocation after total hip arthroplasty

True proper position after total hip arthroplasty was determined by measuring the cup and stem anteversion using computed tomography. We compared 20 dislocated hips (14 posterior and 6 anterior) with 18 non-dislocated hips. Both the cup anteversion and the stem anteversion showed no differences among the groups. The sum of cup and stem anteversion in posterior dislocated hips was significantly lesser than that in non-dislocated hips and the sum in anterior dislocated hips was significantly greater than that in non-dislocated hips. These results suggested even if the cup alone or the stemalone is at proper position, dislocation might occur.     

Enhanced computed tomographic techniques for the evaluation of total hip arthroplasty

Computed tomography (CT) has revolutionized the evaluation of musculoskeletal pathology. Until recently, however, CT of the postoperative orthopaedic patient has been severely limited by its inability to provide useful information in the vicinity of acetabular and femoral implants. Typically the hardware produces extensive artifacts that can markedly degrade the whole image. Methods are now available to reduce the metal artifact. Following hip arthroplasty, these methods have been used to plan for revision arthroplasty and to evaluate the contralateral side for avascular necrosis.     

Acetabular component orientation in intra- and postoperative positions in total hip arthroplasty

Introduction  In total hip arthroplasty (THA), acetabular component orientation has critically important effects on dislocation, range of motion, polyethylene wear, pelvic osteolysis, and component migration. The differences in the pelvic orientation in the intraoperative lateral position for insertion of acetabular component during operation and that in the postoperative supine position for evaluation of acetabular component orientation will be one of the factors, which make outliers in acetabular component orientation. We compared acetabular component orientation between intraoperative lateral position and postoperative supine position in 100 consecutive primary THAs. Materials and methods  A total of 100 consecutive primary THAs (between October 2004 and December 2005) in 100 patients performed by a single surgical team were investigated. Intraoperative anteroposterior radiographs of pelvis in the lateral position and postoperative anteroposterior radiographs of pelvis in the supine position were taken. Acetabular component orientation (vertical tilt and anteversion) were measured using computer software. Results  The absolute values of difference between measurements in the two positions were 5.3° ± 4.5° (mean ± SD) for vertical tilt and 5.1° ± 3.7° for anteversion. The difference in the vertical tilt between the two positions was significant (P < 0.0001). Conclusion  The difference in the acetabular component orientation between the two positions, which might be caused by the difference between intra- and postoperative pelvic orientation, should be considered during THA.     

Computed tomographic measurement of acetabular and femoral component version in total hip arthroplasty

Purpose

The purposes of the present study were (1) to investigate the variation and accuracy of both acetabular and femoral component version on the axial computed tomographic (CT) images, and (2) to better define the associations between the components version and clinical factors.

Methods

We investigated acetabular and femoral component orientation in 1,411 primary total hip arthroplasties that had been performed without computer-assisted navigation. Version of the acetabular and femoral components was measured on the axial CT images.

Results

The component version was significantly greater than the native version in both acetabular and femoral version. There was a significant correlation between the stem and native femoral versions, but not between the acetabular component and native acetabular versions.

Conclusion

This study identifies several features that might help analyse the effect of pre-operative native acetabular and femoral version on the variation of component alignment.     

Proximal femoral anatomy in total hip arthroplasty. A tri-planar computed tomographic assessment

The relationship between the tip of the Greater Trochanter (GT) and the centre of the Femoral Head (FH) is commonly used as reference point to align the femoral component during hip arthroplasty. We performed tri-planar computed tomography analysis of the proximal femoral anatomy in a series of 150 patients (n = 150) to accurately delineate this relationship. The mean location for the centre of the FH was 8.64 mm (95% confidence interval, 9.44-7.83) distal to the tip of the GT. The centre of the FH was found to be distal to the tip of the GT in 90.6% of cases. Hence we would suggest caution in using the tip of the GT as a reference point during total hip arthroplasty as it could be associated with an inadvertent intraoperative leg lengthening.     

Postoperative computed tomographic evaluation of congenital hip dislocation

The use of computed tomography (CT) in the postoperative evaluation of 19 congenitally dislocated hips is presented so that appropriate indications for reduction can be determined and radiologic criteria can be defined for judging whether reduction is satisfactory. The radiologic technique is presented. CT is an accurate and cost-effective modality that is capable of demonstrating subtle changes in femoral head position.     

Outcome of infected total hip arthroplasty. An inclusive, consecutive series

Twenty-one infected total hip arthroplasties in 19 patients performed between 1971 and 1982 were prospectively followed, using a computerized standard orthopaedic arthritis record. These cases represent an inclusive and unselected, consecutive series. The mean follow-up period from time of infection was 4.8 years (range, 1.2-11.7 years). Infection was diagnosed by positive bacteriologic culture. Ten hips grew a staphylococcal species, 5 a single gram-negative organism, 1 a Streptococcus, and 5 multiple organisms. At final follow-up evaluation, only three hips (14%) had the previously infected prosthesis still in situ, and these had no evidence of ongoing deep infection. Five additional hips (24%) were successfully salvaged after one- or two-stage prosthetic exchange. Two hips (10%) have an infected prosthesis in situ. Eleven hips (52%) had resection arthroplasty, three after attempts at prosthetic reinsertion. Therefore, at final follow-up evaluation, only 8 of the 21 hips (38%) have an apparently infection-free salvaged or reinserted prosthesis in place. Good prognostic factors for prosthetic salvage/successful reinsertion include Staphylococcus epidermidis infection and a traumatic etiology necessitating later hip arthroplasty. Poor prognostic factors include infection with Staphylococcus aureus or multiple organisms and a preoperative diagnosis of avascular necrosis.     

The effect of acetabular and femoral component version on dislocation in primary total hip arthroplasty

Purpose

The purpose of the present study was to: (1) investigate the variation of both acetabular and femoral component version in a large series of consecutive primary THA patients, and (2) to better define the associations of acetabular and femoral component alignment and clinical factors with subsequent hip dislocation in those patients.

Methods

We analyzed CT scans of 1,555 consecutive primary THAs and measured version of the components. We also documented the frequency and direction of subsequent dislocation as well as femoral head size, posterior tissue repair, any history of previous hip surgery, and gender.

Results

The dislocation rate after THA was 3.22 %. The dislocation risk was 1.9 times higher if cup anteversion was not between 10° and 30°. Compared to hips that did not dislocate, those that experienced anterior dislocation had a significantly greater combined anteversion; those that dislocated posteriorly had a significantly smaller combined anteversion. Hips with previous rotational acetabular osteotomy or head size smaller than 28 mm correlated with an increased dislocation rate.

Conclusion

The dislocation risk could be higher if cup anteversion was not between 10° and 30°. Greater combined anteversion could be a risk factor of anterior dislocation, and posterior dislocation could be more common in smaller combined anteversion.

     

Prognosis of dislocation after total hip arthroplasty

One hundred sixty-one dislocations after cemented total hip arthroplasty, with a mean follow-up period of 8 years after dislocation, were reviewed with the aim of establishing the prognosis. There were 84% single and 16% recurrent dislocations. Closed reduction was successful in 81% of cases. Thirty-seven percent of dislocations were early (within 5 weeks), 36% occurred in patients who had had previous surgery, and in 47% there was nonunion of the trochanter. There was a two-way interaction between these factors, and all factors were significant for recurrent dislocation. Twenty-six (16%) recurrent dislocations required surgery. The most common causes of recurrent dislocation demonstrated at operation were component malposition (58%) and failure of the abductor mechanism (42%). In total, 96% of cases were successfully treated.     

Study of hip joint dislocation after total hip arthroplasty

The present study was undertaken to identify the factors responsible for hip joint dislocation after total hip arthroplasty, laying emphasis on analysis of the background variables of the patients. Of the 317 hips included in the study, ten (3.2%) dislocated. Only the anteversion angle of the cup differed significantly between the dislocation group and the dislocation-free group. The safe zone of the anteversion angle seems to be between 20 and 30 degrees. but it is also essential to set the antetorsion angle of the stem to match the shape of individual bones to create a more stable hip joint. This safe zone may be expanded by the additive effect of antetorsion angle of the stem.     

全髋关节置换术后早期脱位研究进展

髋关节脱位是全髋关节置换(THA)后仅次于假体松动的主要并发症之一,多发生于术后早期(3个月内).尽管其发生已大大减少,但仍是影响THA疗效的早期并发症之一,对患者的精神和身体打击很大,如何防治一直是关注的焦点.该文就近年来THA后早期脱位研究进展作一综述.     

Congenital dislocation of the hip treated by total hip arthroplasty

Thirty-two total hip arthroplasties (THAs) were performed on 26 severely incapacitated patients with congenital dislocation of the hip. The arthroplasty technique varied with the problems encountered, but the cup was always placed in the true acetabulum. In 19 cases, femoral head autografts were transplanted. The overall results were satisfactory. Roentgenologic evaluation of the bone grafts showed no nonunion or secondary displacement. Nineteen previously invalid patients now lead normal lives. Five patients are minimally incapacitated and only two were unimproved by the operation. THA with autogeneic grafts to deepen the acetabulum is recommended whenever a congenital dislocation of the hip in an adult is associated with severe pain.     

手法复位治疗全髋置换术后的关节脱位

2006年8月～2007年1月，笔者对15例行全髋置换术后脱位患者给予手法复位治疗，取得较满意效果。 1材料与方法 1．1病例资料本组15例，男5例，女10例，年龄63～81岁。患者均为全髋关节置换术后6～9个月出现患肢短缩，略有屈曲、大转子上移、外突、肢体内收、内旋。摄X线片均未见假体周围骨折（见图1A）。     

Oblique femoral osteotomy in cementless total hip arthroplasty: Prospective consecutive series with a 3-year minimum follow-up period

Success of total hip arthroplasty using cementless implants is dependent on intimate contact of the prostheses with viable host—bone and achievement of optimal fit and rigid implant fixation. A technique of oblique femoral osteotomy has been used to correct proximal femoral deformity and to facilitate difficult revision surgery in selected cases. This prospective study included 26 osteotomies performed in 25 consecutive patients with a minimum follow-up period of 3 years. The median follow-up period was 50 months. Eighty-four percent of the reconstructions remained in situ at the final follow-up examination, with 81% of them rated clinically excellent or good. Three stems were revised for aseptic loosening at a mean interval of 46 months. One additional femoral revision was necessary for nonunion of the osteotomy. Two of the remaining stems were classified as radiographically loose. Although oblique femoral osteotomy serves as a useful adjunct surgical technique in difficult femoral reconstructions, nearly 25% of the hips in this study either failed or were loose at the medium-term follow-up examination. Long-term success of this technique with cementless prostheses remains to be defined.     

Cementless total hip arthroplasty in patients with high congenital hip dislocation

BACKGROUND: The optimal surgical treatment for patients with high congenital dislocation of the hip remains controversial. The purpose of our study was to evaluate the mid-term to long-term results of cementless total hip arthroplasty in such patients. METHODS: The study included sixty-eight total hip replacements performed between 1989 and 1994 in fifty-six consecutive patients with high congenital hip dislocation at our hospital. The cup was placed at the level of the true acetabulum, and a shortening osteotomy of the proximal part of the femur and distal advancement of the greater trochanter were performed in 90% of the hips. At the time of final follow-up, at a mean of 12.3 years postoperatively, fifty-two patients (sixty-four hips) were evaluated by us with a physical examination, determination of Harris hip scores, and radiographs. RESULTS: The mean Harris hip score increased from 54 points preoperatively to 84 points at the time of final follow-up (p < 0.001). There was a negative Trendelenburg sign in fifty-nine (92%) of the sixty-four hips. There were thirteen perioperative complications (19%): three peroneal nerve palsies, one femoral nerve palsy, one superior gluteal nerve palsy, four nondisplaced fractures of the proximal part of the femur, one malpositioned stem perforating the posteromedial cortex of the femur, one superficial wound infection, and two early dislocations. With revision because of aseptic loosening as the end point, the ten-year survival rate for press-fit, porous-coated acetabular components was 94.9% (95% confidence interval, 89.3% to 100%). Eight of nine threaded acetabular components were revised, and the ninth was radiographically loose at the time of the last follow-up examination. The rate of survival for the CDH femoral components, with revision because of aseptic loosening as the end point, was 98.4% (95% confidence interval, 96.8% to 100%) at ten years. CONCLUSIONS: Total hip arthroplasty, with placement of the cup at the level of the true acetabulum, distal advancement of the greater trochanter, and femoral shortening osteotomy, can be recommended for patients with high congenital hip dislocation. Complications such as wear, osteolysis, and cup revision were secondary to the suboptimal design of the acetabular components used in this series.     

Cementless porous-coated total knee arthroplasty: 10-year results in a consecutive series

We report the results of 114 AGC 2000 porous-coated, cementless total knee arthroplasties (TKA) performed consecutively in 102 patients during the period 1984-1986. After 10 years, 58 TKAs in 52 patients were evaluated with patient assessment, Hospital for Special Surgery knee score, weight-bearing radiographs done under fluoroscopic control, and survivorship analysis. All dropouts within the first 9 years were patients dying with a functioning TKA except 1 revision secondary to a supracondylar fracture after 8.5 years. Of the patients, 53 (92%) were satisfied or very satisfied with their TKA, and 55 (95%) of the knees were rated good or excellent. There was no pain in 53 knees, and the median knee flexion was 110 degrees. Six radiolucencies >1 mm were found beneath parts of the tibial component, and 5 radiolucencies were seen beneath the femoral component. None had progressed compared with the 5-year follow-up, and in all cases trabeculae could be seen reaching the prosthetic component. No migrations had occurred since the 5-year follow-up. No obvious joint space reduction was seen. Osteolysis presenting as an isolated cyst was found in 1 knee in the lateral tibial condyle and was not progressive. Two tibial components had been revised because of aseptic loosening and 1 because of septic loosening, all within the first 3 years. No femoral or patellar components were revised. The cumulative prosthesis survival rate after 10 to 11 years was 97%. When pain and radiographic loosening also were considered, the success rate was 87%. Cementless insertion of a nonmodular, porous-coated TKA resulted in a long-term durable bone-prosthesis interface. The flat-on-flat articulation did not result in catastrophic polyethylene wear or osteolysis within the first 10 years.     

Primary total hip arthroplasty with a cementless porous-coated anatomic total hip prosthesis: 10- to 12-year results of prospective and consecutive series.

We performed a prospective study in 108 consecutive patients (116 hips) who were followed for a minimum of 10 years (10-12 years) after primary total hip arthroplasty using an uncemented porous-coated anatomic (PCA) hip prosthesis. The average age of the patients at operation was 48.4 years (range, 19-85 years), and the diagnosis was avascular necrosis of the femoral head in 46 hips, neglected femoral neck fracture in 27, osteoarthrosis secondary to childhood pyogenic arthritis in 24, childhood tuberculous arthritis in 5, and miscellaneous in 14. The average preoperative Harris Hip Score was 55 points, which improved to 87 points at 11 years. Seventy-five hips (65%) were excellent, 11 (9%) were good, and 30 (39%) were poor. The overall rate of revision was 15% (17 of 116 hips). The rate of revision of the femoral component was 11% (13 of 116 hips), and the rate of revision of the acetabular component was 15% (17 of 116 hips). The prevalence of thigh pain was 28% at 11 years. The increase in the incidence of aseptic loosening of the femoral component was found to explain the high incidence of severe thigh pain at 11 years' follow-up. At 11 years, there was femoral osteolysis in 69 hips (59%) and acetabular osteolysis in 65 hips (56%). At 6 years, 20 hips (17%) showed definite wear of the polyethylene liner. At 11 years, 81 hips (70%) showed definite wear of the polyethylene liner. Because the complication rate of the PCA hip prosthesis with respect to loosening, osteolysis, and excessive wear in the polyethylene liner is high, we abandoned the use of this implant.     

非骨水泥型全髋关节置换治疗成人高位发育性髋脱位

目的：分析和总结成人高位发育性髋脱位患者的非骨水泥型全髋关节置换手术方法及疗效。方法：对1999年5月～2002年7月接受Zweymuller非骨水泥型全髋关节置换术的9例(11髋)成人高位发育性髋脱位患者进行随访。男1例，女8例，平均年龄29．4岁，均为Hartofilakidis Ⅲ型。临床症状主要为患髋疼痛、不稳定和跛行。术前Harris评分平均为40．2分。双下肢长度差异平均4．1cm,脱位高度平均4．8cm。术中臼杯均安装于真臼处，臼杯骨量覆盖80％以上。脱位高度5cm以上4髋，采用股骨小转子下截骨，余7髋经单纯软组织松解后复位。结果：平均随访18．2个月。临床症状基本消失，双下肢长度差异平均1．1cm。1例术中股神经不全损伤，术后4个月恢复。Harris评分平均90分。所有患者最后随访时对治疗结果满意。结论非骨水泥型全髋关节置换对成人高位发育性髋脱位的治疗是一种较理想的方法，能很大程度地改善患者的生活质量。脱位高度小于5cm者，经软组织松解后能完全下拉复位，不会造成股神经及坐骨神经永久性麻痹。手术操作相对简单，即使发生松动也便于翻修。     

全髋关节置换术后脱位原因研究进展

全髋关节置换术(THA)日趋成熟,其并发症也逐步受到重视,人工关节脱位为常见且严重的主要并发症。THA后脱位一旦发生,治疗通常较困难,因此全面了解脱位的原因并采取相应的预防措施显得十分重要。该文就近年THA后人工关节脱位原因之患者相关因素、手术相关因素、假体因素及术前教育与术后护理等的研究进展作一简要综述。