Minor column structural acetabular allografts in revision hip arthroplasty

A minor column (shelf) allograft is used for uncontained defects that involve less than 50% of the acetabulum. The prospectively collected records and radiographs of 47 patients (51 hips) who had undergone minor column structural acetabular allograft reconstruction during revision hip arthroplasty were reviewed. The purpose was to identify the long-term results (minimum 5 years) and factors that may influence longevity of the allograft and predispose the patient to subsequent acetabular component failure. The mean duration of followup was 119 months (range, 68-195 months). There was one perioperative death and six patients were lost to followup. Eleven patients (22%) required additional surgery. Three acetabular cups could not be revised successfully, despite multiple attempts, and the patients were treated with Girdlestone excisions. Eight patients underwent successful revision surgery with only three requiring a repeat structural allograft. Survival time for the acetabular cup as determined by Kaplan-Meier analysis was 153 months (95% confidence interval; range, 136-169 months). Cup failure was associated with more operative procedures performed before revision surgery (mean, 3.2 procedures), and failure to restore the vertical center of hip rotation to within 12 to 14 mm of the predicted value. The acetabular abduction angle was not a predictor for failure. The current study shows that good results can be achieved with structural acetabular allograft reconstruction with mid-term to long-term implant survival (cup aseptic survival, 80.4% and allograft re-construction survival, 94.1%), especially if there is restoration of near normal hip biomechanics.     

The fate of massive allografts in total hip acetabular revision surgery.

A series of 23 major load-bearing acetabular allografts done in conjunction with revision total hip arthroplasty were prospectively evaluated. This study includes cases with a minimum 2-year follow-up period. The procedures were performed using noncemented porous-coated acetabular components with pegs. In seven acetabula there was no change in cup position when compared with the initial postoperative roentgenogram (35%). Six acetabula migrated 3-5 mm during the first 2 years, then became stable without further progression (28.6%). In six cases (30%) gross loosening and migration occurred, requiring revision to a larger cup. One case required exchange arthroplasty for infection (5%). All biopsies taken at the time of the revision for failure showed viable bone replacing allograft. If the criteria for success of major superior acetabular allografts include incorporation of the graft and long-term stability of the implant, then the success rate in this series is very low. Only 7 of 20 hips were successful over a relatively short time period. However, if expectations are lowered, and the procedure is considered successful if adequate bone stock is restored to the acetabulum to allow reconstruction with a cementless cup firmly fixed in viable bone, then all but three revisions were successful.     

Safe screw placement in acetabular revision surgery

Revision of an acetabular component with extensive bone loss is a procedure that sometimes includes allografting or the placement of an unusually sized or positioned uncemented acetabular component. We evaluated the quadrant system used to guide screw placement in primary uncemented total hip surgery in the high hip center, jumbo component, and 3 designs of reinforcement rings. We used 14 pairs of cadaver hemipelves, which were prepared by removing all soft tissues except the medial neurovascular structures. With each implant, all screw holes were tested to determine if they followed the safe quadrant recommendations. In the high hip center, the center and anterior of the superoposterior quadrant was dangerous. All of the other implants met the quadrant recommendations.     

Femoral and acetabular revision using impacted nondemineralized freeze-dried bone allografts

Background  Favorable results have been obtained by the use of deep-frozen bone allografts in total hip arthroplasty. However, owing to the shortage of deep-frozen allografts and the risk of infectious disease, other materials have been studied, such as sterile nondemineralized freeze-dried allografts. The aim of this study was to describe midterm clinical outcomes and radiographic bone incorporation of human freeze-dried bone grafts in 42 revision total hip arthroplasty procedures using cancellous impacted bone grafting. Methods  This report presented clinical and radiographic evidence of allograft incorporation in 42 hip reconstructions performed between 1996 and 2002. The patient group included 13 (31%) men and 29 (69%) women with mean ± SD age of 63 ± 14 years (range 28–80 years). Meanfollow-upwas 82 months (range 63–127) months. Clinical analysis was based on the D’Aubigné-Postel score. Radiographic incorporation was defined according to specific criteria. Results  The D’Aubigné and Postel criteria showed adequate outcome in 38 (90%) of the patients. The radiographic evaluation revealed that allograft remodeling and incorporation were found in 39 (93.0%) and 36 (86.5%) of acetabular and femoral cases, respectively. The overall graft survival rate at an average follow-up of 8 years (range 5–10 years) was 90%. Conclusions  Bone grafts obtained by the lyophilization process developed and carried out in our tissue bank provide suitable grafts for revision total hip arthroplasty. Clinical and radiographic midterm results were excellent, indicating that nondemineralized freeze-dried bone allografts are suitable for replacing deep-frozen grafts.     

Clinical and radiographic assessment of cementless acetabular revision with morsellised allografts

The aim of this study was to evaluate the clinical and radiographic results of cementless acetabular revision with deep frozen morsellised allografts. Sixty-one patients (65 hips) underwent acetabular revision using cementless components and deep frozen morsellised allografts. Fifty-seven hips (53 patients) were reviewed at a mean of 105.1 months (range 72–180 months) after revision. The study group included 29 males and 24 females with a mean age of 46.4 years. One cup underwent further revision for aseptic loosening and two were defined as radiographic failures. The mean time for allograft incorporation was 12.5 months (range 6–24 months) after index surgery. The mean Harris hip score of the patients improved from 61.1 points preoperatively to 91.6 points postoperatively. Linear and cavitary osteolysis was observed in two and 12 hips, respectively. The acetabular revision using cementless components with deep frozen morsellized allografts provides favourable clinical and radiographic results, although the initial disease and age may adversely affect the outcomes.     

The Burch-Schneider antiprotrusio cage in acetabular revision surgery

A total of 38 acetabular revisions using a Burch-Schneider antiprotrusio cage in 37 patients (18 women and 19 men), with a mean age at surgery of 75 years (range, 55–88 years), were evaluated retrospectively with a mean follow-up of 12 years (range, 8–21 years). In 2 cases with total hip dislocation and in 1 case with a deep infection, revision of the antiprotrusio cages was required. Defining every revision of the antiprotrusio cage as the endpoint of survivorship, the antiprotrusio cage showed a survival rate of 92% after 21 years. Clinical evaluation of the surviving patients showed a mean Harris hip score of 76 points (range, 20–96). Radiologic evaluation revealed that 1 antiprotrusio cage was loose and that 4 femoral stems were loose. The Burch-Schneider antiprotrusio cage compares favorably with other devices with regard to long-term implant survival rate.     

Revision of failed acetabular cups with extensive structural allografts

AIM: Structural allografts are used with encouraging results for revision of failed total hip arthroplasty and in the surgery of bone tumours. The aim of the present study is to describe the clinical and radiological results achieved with structural allografts in revision of a total hip arthroplasty. MATERIAL AND METHODS: 15 patients (12 female and 3 male patients) were revised with an acetabular defect situation of type 3 A or 3 B according to the Paprosky classification. Five fresh-frozen acetabula, nine distal femora and one proximal tibia were used for acetabular reconstruction. The rigid graft fixation was performed with 2 > or = AO screws. In one case a cemented acetabular ring was implanted, four cementless cups and ten cemented polyethylene acetabular components were used. The mean follow-up was 7.9 years (1.6-11.0 years). RESULTS: A stable osseointegration of fifteen transplanted structural allografts was achieved in thirteen cases. Two allografts (one aseptic loosening, one deep infection) failed to osseointegrate. In one case the migration of a cementless cup was registered. Revision surgery of this female patient was performed successfully with a cemented reconstruction ring. The mean Harris hip score at the latest follow-up was 81.4 points (70-99 points). CONCLUSION: For reconstruction of acetabular bone stock and restoration of the bone anatomy structural allografts can be recommended. The use of cementless cups in combination with structural grafts is to be evaluated as critical.     

Primary stability of acetabular reinforcement implants in revision surgery

It was the purpose of this biomechanical in vitro study to characterize the initial mechanical stability of 3 different acetabular reinforcement prostheses as a function of implant design and bone stock conditions. Müller and Ganz rings and Burch-Schneider cage (Protek, Münsingen, CH) were fixed using 3 screws in normal acetabuli and in acetabuli with 5 different simulated conditions of segmental bone-stock defects. A servohydraulic testing machine (Instron, Canton, USA) was used for the inquiry. Preparations were tested to determine axial stability (2354 N). Three electromagnetic displacement transducers (Micro-Epsilon, Ortenburg, D) were placed in the 3 main quadrants of the acetabular rim to detect the micromotion of the implant. The amount of micromotion depended on the size of the defect and contact area of the prosthesis. All of the implants were stable (< 123 microns) in all quadrants of normal acetabuli and in case of ectasis, protrusio, and ventral defects. Displacement of more than 200 microns was observed at the ilium with the Muller implant in acetabuli with cranial defect (p < 0.05) and with both rings in acetabuli with dorsal defect. The Burch-Schneider cage was stable in all conditions, but displacement of more than 350 microns was observed in acetabula with pseudoarthrosis. The 3 reinforcement implants showed low displacement rates in most of the acetabular bony defects. The experimental data suggests that careful preoperative evaluation and intraoperative assessment to match bone defects and reinforcement implants are of paramount importance to achieve good stability.     

Early results of revision acetabular cup using antiprotrusio reconstruction rings and allografts

Background:Hip arthroplasty is one of the most frequently performed orthopedic procedures with high scores of success while its most common complication is aseptic loosening of the acetabular component, which may result from host bone loss or even from pelvis discontinuity. The purpose of the study was to evaluate results in patients after revision acetabular arthroplasty with reconstruction rings and allografts.Results:The mean followup period of the patients was 7.2 years (range 3-19 years). A Kaplan–Meier analysis showed that a 3- and 10 year survival rate was 92.8% and 84.8% respectively, using further revision for any reason of the acetabular device as an end point. Eight patients revealed implant related complications. Four patients presented with ring loosening, one with a loose acetabular polyethylene cup, two hips demonstrated recurrent dislocations and one patient was with deep infection. Regarding the remaining 61 patients without re-revision surgery, the mean Harris hip score improved from 30.5 to 73.8 points.Conclusion:A modified, antiprotrusion cage provides an acceptable survival rate and radiological results, but complications could still be expected. It seems that the observed massive bone loss with pelvic discontinuity and an insufficient fixation of the cage to the ischium may result in implant loosening. Stable fixation of the ischial ring flange with screws is an essential condition to expect a good outcome.     

Vastus-psoas release for acetabular exposure in revision hip surgery

A technique is presented for wide exposure of the acetabulum for revision total hip arthroplasty surgery in the presence of a solidly fixed, modular, or monoblock femoral component without the need for trochanteric osteotomy. The technique involves release of the proximal portion of the vastus lateralis, vastus intermedius, and vastus medialis muscles and the iliopsoas tendon from the femur and placement of the femoral head/neck posterior to the acetabulum. The exposure afforded by this release usually precludes the need for trochanteric osteotomy and/or removal of a well-fixed femoral component in revision surgery that is being done for isolated loosening of acetabular components, thereby decreasing operative time, morbidity, and the risks of complication of trochanteric osteotomy.     

The survival of support rings in complex acetabular revision surgery

Between 1980 and 2000, 63 support rings were used in the management of acetabular deficiency in a series of 60 patients, with a mean follow-up of 8.75 years (2 months to 23.8 years). There was a minimum five-year follow-up for successful reconstructions. The indication for revision surgery was aseptic loosening in 30 cases and infection in 33. All cases were Paprosky III defects; IIIA in 33 patients (52.4%) and IIIB in 30 (47.6%), including four with pelvic dissociation. A total of 26 patients (43.3%) have died since surgery, and 34 (56.7%) remain under clinical review. With acetabular revision for infection or aseptic loosening as the definition of failure, we report success in 53 (84%) of the reconstructions. A total of 12 failures (19%) required further surgery, four (6.3%) for aseptic loosening of the acetabular construct, six (9.5%) for recurrent infection and two (3.2%) for recurrent dislocation requiring captive components. Complications, seen in 11 patients (18.3%), included six femoral or sciatic neuropraxias which all resolved, one grade III heterotopic ossification, one on-table acetabular revision for instability, and three early post-operative dislocations managed by manipulation under anaesthesia, with no further instability. We recommend support rings and morcellised bone graft for significant acetabular bone deficiency that cannot be reconstructed using mesh.     

Supercharging irradiated allografts with mesenchymal stem cells improves acetabular bone grafting in revision arthroplasty

Purpose

The procedure of bone allografting associated with a reinforcement device is widely used for acetabulum revision. However in absence of biologic fixation of the allograft, failure of the reconstruction may occur. We made the hypothesis that it would be possible to load these grafts with bone marrow derived mesenchymal stem cells (MSC) to rescue the osteogenic capacity of an allogenic dead bone and therefore enhance incorporation of allografts with the host bone and decrease the number of failures related to the allograft.

Method

We identified 60 patients who had undergone acetabular component revision for aseptic failure of cemented implants associated with massive periacetabular osteolysis and Paprosky type 3A or 3B classification (without pelvic discontinuity) between 1996 and 2001. The study group of 30 patients received MSCs in the allograft and at the host graft junction. The average total number of MSCs received by each patient was 195,000 cells (range 86,000–254,000 cells). The control group of 30 patients had no MSCs in the allograft. Patients were matched for the size of periacetabular osteolysis (Paprosky type 3A or 3B). We compared the evolution of the allografts and evaluated cup migration and revision of the hips as end points at a minimum of 12 years or until failure.

Result

Better radiographic graft union rates and less allograft resorption were observed with allografts loaded with stem cells. Allograft resorption was significantly decreased in the group with allograft loaded with MSCs (1.2 cm² —range 0–2.3 cm²—of resorption on radiographs in the group with MSCs; versus 6 cm², range 2.1–8.5 cm² in the group without MSCs). The rate of mechanical failure was highest (p?=?0.01) among the 30 patients with allograft without stem cells (9/30; 30 %) compared with no failures for patients with allograft loaded with stem cells. Revision of the cup was necessary in nine patients in the control group. No revision was performed in the 30 patients of the study group with MSCs.

Conclusion

For acetabular defect reconstruction, loading the allograft with MSCs has resulted in a lower rate of failure as compared with allograft without MSCs.     

Use of freeze-dried bone allografts in revision total hip arthroplasty

Acetabular loosenings with severe bone loss require a large amount of graft material to fill the defect. Although all donors are systematically subjected to serologic screening, bone allografts that are chemically processed, freeze-dried, and radiosterilized ensure a higher level of microbiological safety than radiosterilised deep-frozen allografts. The bone allograft used in this study meets this requirement. Therefore, it was both interesting and important to evaluate its outcome in revision acetabuloplasty. This phase II multi-centre study involves 44 revision total hip replacements (35 evaluable) in patients with acetabular bone defects who received allografts obtained from femoral heads harvested from living donors. The results obtained at 40 months follow-up confirmed that reconstructions using a small amount of graft material have a satisfactory outcome. Where an allograft is used in association with an acetabular ring, good primary stability is provided by the ring and secondary stability is ensured by graft incorporation (which, in our study, has often shown to be enhanced by the use of bone cement). The advantages of this type of bone allograft are its greater ease of use and storage at room temperature.     

Use of custom triflanged acetabular components in revision total hip arthroplasty

Difficulty persists in consistently treating massive acetabular defects in revision total hip arthroplasty. A relatively new treatment option for these complex cases is a custom triflanged acetabular component created from anatomic data derived from a computed tomography scan of the pelvis. The custom triflanged acetabular component achieves fixation on the remaining ilium, ischium, and pubis with multiple fixation screws while the acetabular defect is filled with cancellous allograft bone. A retrospective review was done of 26 hips (26 patients) with massive periacetabular bone loss (Paprosky Type 3B) reconstructed with a custom triflanged acetabular component. Twenty-three of 26 patients (88.5%) were considered clinically successful at short-term followup (average, 54 months; range, 24 to 85 months), with stable fixation and reconstruction of periacetabular bone. Three failures occurred from loss of ischial fixation in two patients with a preoperative pelvic discontinuity and one patient with severe osteopenia. These devices should be used with caution in patients with a preoperative pelvic discontinuity unless additional column plating is done.     

The use of structural proximal femoral allografts in complex revision hip arthroplasty

Between April 1992 and November 1998 we used 34 massive proximal femoral allografts for femoral reconstruction at revision hip arthroplasty. Seven patients have died and two have been lost to follow-up. There were thus 25 grafts in 24 patients for review. The mean follow-up was 53 months (16 to 101). By the time of the review two patients had undergone a further revision for failure of the allograft. Another had required secondary plating and grafting at the graft-host junction for symptomatic nonunion. One had recurrence of deep sepsis and was being managed conservatively. Trochanteric union was considered to have occurred radiologically in 16 of the 25 grafts and union at the host-graft junction in 20. Resorption of the allograft was significant in only two hips. We recommend this technique in cases in which femoral bone loss has been catastrophic.     

大直径陶瓷-陶瓷股骨头在保留股骨假体全髋关节翻修术中的应用

目的评价大直径陶瓷-陶瓷股骨头在保留股骨假体全髋关节翻修术中应用的临床疗效。方法回顾性分析自2006-01—2012-12在保留股骨假体全髋关节翻修术中应用直径36 mm陶瓷-陶瓷股骨头假体的32例（32髋）的临床资料。手术前后评估髋关节功能Harris评分,术后6周、6个月、1年及随后每隔半年随访中临床及X线片评价是否出现假体脱位、松动、下沉、骨溶解、陶瓷碎裂。结果 32例均获得随访平均26.2（11.0-38.0）个月。末次随访时髋关节功能Harris评分从术前平均68.9（9.0-87.0）分提高到85.0（39.0-98.0）分,差异有统计学意义（t=17.36,P=0.013）。均未出现假体脱位、松动、下沉、骨溶解、陶瓷破碎。结论大直径陶瓷-陶瓷股骨头在保留股骨假体的全髋关节翻修术中可以显著降低术后假体脱位率,不增加股骨侧假体周围骨溶解,可以获得较好的近、中期疗效。