Uncemented acetabular components with bulk femoral head autograft for acetabular reconstruction in developmental dysplasia of the hip: results at five to twelve years.

BACKGROUND: Anterolateral acetabular bone deficiency is one of the technical problems associated with total hip arthroplasty in patients with developmental hip dysplasia. The purpose of this study was to evaluate the results of one method of acetabular reconstruction for hip dysplasia-placement of an uncemented socket in conjunction with a bulk femoral head autograft. METHODS: Forty-four hips in thirty-five patients (twenty-nine female and six male; average age, thirty-nine years) with developmental hip dysplasia were treated with primary total hip arthroplasty with use of an uncemented porous-coated titanium cup fixed with screws and an autogenous bulk femoral head graft. The patients were followed clinically in a prospective fashion for five to 12.3 years (mean, 7.5 years), and radiographs were analyzed retrospectively. RESULTS: Four acetabular components were revised: two, because of severe polyethylene wear and osteolysis; one, because of aseptic loosening; and one, because of fracture of the acetabular shell. The mean Harris hip score for the unrevised hips improved from 51 points preoperatively to 91 points postoperatively. No unrevised socket had definite radiographic evidence of loosening. Forty-three of the forty-four hips had no radiographic evidence of resorption of the graft or had radiographic evidence of resorption limited to the nonstressed area of the graft lateral to the edge of the cup. CONCLUSIONS: This method of reconstruction provided reliable acetabular fixation and appeared to restore acetabular bone stock in patients with developmental hip dysplasia. We use this technique for patients with moderate anterolateral acetabular bone deficiency requiring total hip arthroplasty.     

Acetabular reconstruction with bone impaction grafting and a cemented cup: 20 years' experience.

Acetabular bone stock loss compromises the outcome in primary and revision total hip arthroplasty. In 1979, a biologic method was introduced with tightly impacted cancellous allografts in combination with a cemented polyethylene cup for acetabular reconstruction. With this technique, it is possible to replace the loss of bone and to repair normal hip mechanics and hip function with a standard implant. Based on the authors' 20 years experience, a review of the long-term data is presented in primary total hip arthroplasty with preexisting acetabular bone stock loss, primary total hip arthroplasty in rheumatoid arthritis, patients who had bone impaction when younger than 50 years, and in acetabular revisions. The survival rate with revision of the cup for aseptic loosening as the end point was 94% at 10 to 17 years, 90% at 10 to 18 years, 91% at 10 to 17 years, and 92% at 10 to 15 years. From biopsy specimens from humans and histologic data in animal experiments the incorporation of these impacted bone chips was proven. The acetabular bone impaction technique using large morselized bone chips (range, 0.7-1 cm) and a cemented cup is a reliable technique with favorable long-term outcome.     

Septische Lockerung eines Wagner-Revisionsschaftes durch Mycobacterium tuberculosis.

Only a few cases of specific tuberculous infections of total hip arthroplasties have been published. We report the case of a 66-year-old male patient who received a cementless total hip arthroplasty due to osteoarthritis of the left hip in 1990. Four years later, revision arthroplasty with a Wagner revision stem was performed because of aseptic loosening. In 1995 revision of a loosened acetabular cup was necessary. In 1996 we saw the patient for the first time in our outpatient unit. He complained of increasing pain in the region of the left hip. X-rays showed loosening of the Wagner stem. Aspiration of the synovial fluid of the left hip revealed an infection with mycobacterium tuberculosis (radioimmunoassay). There were no signs of tuberculous infection in the patient's history. Treatment consisted of removal of the prosthesis followed by antituberculosis chemotherapy for 12 months with rifampicin, ethambutol, isoniazid, and pyrazinamide. In April 2001 revision of the left hip joint and implantation of a MRP titanium revision stem and reconstruction of the acetabulum with an acetabular reconstruction ring was done. Until today the patient exhibits no signs of recurrence of the tuberculous infection.     

螺旋臼全髋关节置换术治疗发育性髋关节发育不良

目的探讨使用螺旋臼假体治疗发育性髋关节发育不良（DDH）继发骨性关节炎患者的临床疗效。方法自2003年5月至2007年12月，使用Zweymaller螺旋臼假体治疗40例（43髋）DDH继发骨性关节炎患者，其中男6例（6髋），女34例（37髋），平均年龄47．6岁（22～70岁）；单侧37例，双侧3例；Crowe分型：Ⅰ级6例，Ⅱ级24例，Ⅲ级10例，Ⅳ级3例。平均随访24．6个月，术前Harris评分最高61分，最低22分，平均43．5分。结果所有患者术后疼痛基本消失，双下肢长度差异平均1．2cm，2例术后出现股神经损伤症状，术后6个月症状基本消失，Harris评分最高97分，最低62分，平均85．3分。结论使用Zweymtiller螺旋臼假体治疗DDH继发骨性关节炎的患者，可以达到良好的恢复关节功能的临床疗效，手术不需大块植骨和骨水泥，初期临床效果满意。     

Vertical acetabular positioning with an inclinometer in total hip arthroplasty

Vertical acetabular implant positioning is an important technical aspect in total hip arthroplasty. To evaluate the potential benefit of an inclinometer, 50 cup insertions were done on a cadaver pelvis. Acetabular cup vertical angles averaged 44.4 degrees +/- 11.4 degrees by visuospatial perception and 42.2 degrees +/- 3.8 degrees with the inclinometer. All cups were within the safe angle range of 40 degrees to 49 degrees with the inclinometer compared with 64% of cups by visuospatial perception. Use of the inclinometer reduced variability by a factor of 2.0 to 4.5. The addition of an inclinometer for acetabular cup insertion increases the probability of positioning the cup within a vertical safe range during total hip arthroplasty on a cadaver pelvis, suggesting that it could be a useful adjunct in clinical practice.     

Radiographic assessment of acetabular cup orientation. A new design concept

An acetabular cup with a 270 degree rim wire has been designed to assist in the radiographic assessment of acetabular cup orientation in total hip arthroplasty. A study was conducted analyzing the component in various positions of lateral opening and version with three different X-ray-beam centering positions. The 270 degree acetabular rim wire allowed for easy and accurate assessment of component orientation when the pelvis was level and the central ray of the X-ray beam was centered over the hip.     

Limitations of Imageless Computer-Assisted Navigation for Total Hip Arthroplasty

We prospectively evaluated acetabular cup placement in total hip arthroplasty with an imageless computer navigation system or using conventional manual technique. The achieved cup orientation in the manual group had substantially larger variances and greater placement error than the navigation cases. The use of navigation was abandoned in 3 cases because of excessive pelvic tilt and unreliable registration of the pelvis. Computer navigation system helped improve the accuracy of the acetabular cup placement for total hip arthroplasty in this study. The variation between the intraoperative navigation readings and the computed tomographic values suggests that relying on palpation of bony landmarks through drapes and tissue is a limitation of this method. Further, the variation in pelvic tilt has an effect on cup placement that requires further studies.     

Intrapelvic cyst formation after hip arthroplasty with a carbon fibre-reinforced polyethylene socket

Carbon fibre-reinforced polyethylene cups were inserted in total hip arthroplasties for both hips of a male patient. Ten years after the arthroplasty of the right hip, an intrapelvic cyst was observed. The cyst was connected to the inner acetabular wall. The endoprosthetic cup showed gross loosening with a marked osteolysis of the acetabulum. Revision arthroplasty with allograft bone and an uncemented endoprosthesis was successfully performed. The fibrotic tissue at the bone-cement interface showed numerous histiocytic cells with cytoplasmic infiltrates of carbon and polyethylene particles. The left hip was also later revised for loosening, but no cyst formation was observed on that side.     

Effectiveness of an Acetabular Positioning Device in Primary Total Hip Arthroplasty

To evaluate the efficacy of a commercially available acetabular positioning device, we performed a prospective evaluation of 40 consecutive patients undergoing primary total hip arthroplasty. All surgery was performed by the same surgeon, in the same operating room, and on the same operating table. The acetabular positioning device was designed to place the component in 45° of abduction. At 6 weeks, all radiographs were evaluated by 3 investigators not involved with the surgery. Each radiograph was evaluated by each reviewer on 3 separate occasions, blinded to the findings of the other reviewer to assess interobserver and intraobserver variability. The mean cup abduction angle was 42.1°, with a range from 23° to 57° (SD 8.3°). Intraobserver and interobserver variability were 0.2 and 0.3°, respectively. The findings of this study demonstrate a wide variability in acetabular cup placement in primary total hip arthroplasty. We believe this is due to movement of the pelvis, which may occur during preparation, draping, and retracting during surgery. We feel surgeons should not rely solely on positioning devices when implanting the acetabular component in total hip arthroplasty. Identification of bone landmarks and determination of superolateral implant coverage noted on preoperative templating is advocated to improve the precision of component position.     

A preliminary review of the Müller acetabular and Burch-Schneider antiprotrusio support rings

A high incidence of acetabular loosening following total hip arthroplasty is emerging as long term follow-up studies become available. The Müller and Burch-Schneider acetabular supports are indicated for acetabular deficiencies which are frequently present during revision hip arthroplasty. The Burch-Schneider support is indicated where the deficiencies are of such magnitude that the Müller ring does not have stable seating prior to screw fixation. These devices bring the resultant of forces across the hip joint under the acetabular roof and provide metal backing for the acetabular cup. They have the additional advantage of screw fixation which in the Müller ring is in line with the resultant of forces across the hip joint. In a one to three year follow-up of twenty-five hip replacements in twenty-four patients, the Müller support ring was used in twenty hips and the Burch-Schneider in five hips. The results were satisfactory and indicate that these supports are valuable in the treatment of patients with acetabular deficiencies.