Acetabular revision with impaction bone grafting and a cemented polyethylene acetabular component: comparison of the Kaplan-Meier analysis to the competing risk analysis in 62 revisions with 25 to 30 years follow-up.

We present the results of 62 consecutive acetabular revisions using impaction bone grafting and a cemented polyethylene acetabular component in 58 patients (13 men and 45 women) after a mean follow-up of 27 years (25 to 30). All patients were prospectively followed. The mean age at revision was 59.2 years (23 to 82). We performed Kaplan-Meier (KM) analysis and also a Competing Risk (CR) analysis because with long-term follow-up, the presence of a competing event (i.e. death) prevents the occurrence of the endpoint of re-revision. A total of 48 patients (52 hips) had died or had been re-revised at final review in March 2011. None of the deaths were related to the surgery. The mean Harris hip score of the ten surviving hips in ten patients was 76 points (45 to 99). The KM survivorship at 25 years for the endpoint 're-revision for any reason' was 58.0% (95% confidence interval (CI) 38 to 73) and for 're-revision for aseptic loosening' 72.1% (95% CI 51 to 85). With the CR analysis we calculated the KM analysis overestimates the failure rate with respectively 74% and 93% for these endpoints. The current study shows that acetabular impaction bone grafting revisions provide good clinical results at over 25 years.

Acetabular revision with impacted morsellised cancellous bone grafting and a cemented acetabular component: a 20- to 25-year follow-up.

We present an update of the clinical and radiological results of 62 consecutive acetabular revisions using impacted morsellised cancellous bone grafts and a cemented acetabular component in 58 patients, at a mean follow-up of 22.2 years (20 to 25). The Kaplan-Meier survivorship for the acetabular component with revision for any reason as the endpoint was 75% at 20 years (95% confidence interval (CI) 62 to 88) when 16 hips were at risk. Excluding two revisions for septic loosening at three and six years, the survivorship at 20 years was 79% (95% CI 67 to 93). With further exclusions of one revision of a well-fixed acetabular component after 12 years during a femoral revision and two after 17 years for wear of the acetabular component, the survivorship for aseptic loosening was 87% at 20 years (95% CI 76 to 97). At the final review 14 of the 16 surviving hips had radiographs available. There was one additional case of radiological loosening and four acetabular reconstructions showed progressive radiolucent lines in one or two zones. Acetabular revision using impacted large morsellised bone chips (0.5 cm to 1 cm in diameter) and a cemented acetabular component remains a reliable technique for reconstruction, even when assessed at more than 20 years after surgery.

[Favourable long-term results from cemented total hip arthroplasty combined with acetabular bone impaction grafting in patients under the age of 50]. / Goede langetermijnresultaten van een gecementeerde totaleheupprothese in combinatie met een acetabulumreconstructie met geïmpacteerde botsnippers bij patiënten jonger dan 50 jaar.

OBJECTIVE: Determination of long-term results of hip replacements in patients who, at the time of operation, were under the age of 50. Procedures whereby an existing acetabulum defect was filled with bone chips that were impacted into a strong layer, after which a cemented total hip prosthesis was implanted. DESIGN: Descriptive. METHOD: Prospectively collected data from patients who were under the age of 50, and had undergone a hip replacement operation at our hospital between 1 July 1979 and 31 December 1987 were analysed. Data were collected up to 31 December 2002. The main outcome was time to revision. Survival was calculated by the Kaplan-Meier method. RESULTS: The study group consisted of 25 patients, 17 women and 8 men with 29 prosthetic hips. The average age at operation was 37.6 years (range: 20-49). Follow-up time was 15-23 years (median: 18.7 years). 1 patient (1 hip) was lost to follow-up. 3 patients (4 hips) died within 15 years after the operation; none of them had undergone revision. 4 revisions had been performed: I septic loosening (14 years p.o.) and 3 aseptic loosenings (6, 15, 20 years p.o.). The cumulative survival with the end-point 'revision for any reason' was 96% (95% CI: 88-100) at to years and 88% (95% CI: 74-100) at 20 years; after exclusion of the septic loosening the survival at 20 years was 92% (95% CI: 80-100). CONCLUSION: Hip replacement including a reconstruction technique for an acetabulum defect in patients under the age of 50 was regarded as successful if after 10 years, at least 90% of the prostheses were still in situ.

Acetabular revision with impacted morsellised cancellous bone grafting and a cemented cup. A 15- to 20-year follow-up.

This study presents the clinical and radiological results of 62 consecutive acetabular revisions in 58 patients, at a mean of 16.5 years follow-up (15 to 20). The Kaplan-Meier survivorship for the cup with end-point revisions for any reason, was 79% at 15 years (95% confidence interval (CI); 67 to 91). Excluding two revisions for septic loosening at three and six years, and one revision of a well-fixed cup after 12 years in the course of a femoral revision, the survivorship was 84% at 15 years (95% CI; 73 to 95). At review there were no additional cases of loosening, although seven acetabular reconstructions showed radiolucent lines in one or two zones. Acetabular revision using impacted large morsellised bone chips (0.7 cm to 1.0 cm) and a cemented cup, is a reliable technique of reconstruction, when assessed at more than 15 years.

Cemented total hip arthroplasty with impacted morcellized bone-grafts to restore acetabular bone defects in congenital hip dysplasia.

We evaluated the results of 27 acetabular reconstructions in 21 patients with secondary osteoarthritis resulting from congenital dysplasia of the hip in which the acetabular bone defects were restored with impacted morcellized bone-grafts in combination with a cemented cup. At an average follow-up of 7 years, 7 months (range, 5-15 years), 2 hips were revised. One cup was revised after 27 months for sciatic nerve problems; the other hip was revised for aseptic loosening of the cup at 12 years' follow-up. The cumulative survival of the acetabular reconstruction was 96.3% at 5- and 10-year intervals. Additionally, 2 hips (7.7%) showed stable radiolucent lines in zone III without migration of the cup. None of the cemented stems were revised. The bone impaction grafting technique is a safe and attractive method to restore bone deficiencies in dysplastic hips.

Time-dependent mechanical properties of HA/TCP particles in relation to morsellized bone grafts for use in impaction grafting.

In reconstructive surgery human bone defects are sometimes filled with the use of the impaction bone grafting technique. Currently different types of biomaterial particles are being developed as bone-substitute materials. Before these biomaterials can be applied their mechanical and biological behavior should be characterized. In this study the time-dependent mechanical behavior of biomaterial particles with different tri-calcium-phosphate/hydroxy-apatite (TCP:HA) ratios, particle sizes, and porosities is determined and compared to the behavior of human bone grafts, the latter being the standard material currently used to augment bone defects. The mechanical properties were assessed with the use of dynamic confined compression creep tests with a loading and unloading phase. Different graft material groups were tested, consisting of 100% human bone grafts, 100% biomaterial particles, and 50:50 weight mixtures of human grafts and biomaterial particles. No damage to the particles was observed by the impaction in the test chamber or by the dynamic load. Relative to the human graft material, the biomaterial particles hardly deformed under loading, were much stiffer, and showed almost no viscoelastic behavior. The mixtures showed intermediate results. Particle size and porosity influenced the behavior of the biomaterial particles. TCP:HA ratio did not have a great effect. The conclusion is that the application of these particles should be done with great care, as their mechanical behavior is drastically different than that of the human graft material. Mixing it with human bone grafts gave the material some biphasic, viscoelastic behavior that may be important for its biological response.

Favorable results of acetabular reconstruction with impacted morsellized bone grafts in patients younger than 50 years: a 10- to 18-year follow-up study of 34 cemented total hip arthroplasties.

We report a long-term review of 41 acetabular reconstructions using impacted morsellized bone grafts and a cemented total hip arthroplasty (THA) in patients younger than 50 (22-49; average 38) years. Reconstruction was performed in 23 primary THA (19 patients) and 18 revision THA (17 patients). 3 patients were lost to follow-up and 3 (4 hips) died within 10 years of surgery; none had a revision. Thus, 34 hips (30 patients) were reviewed with an average follow-up of 13 (10-18) years. In 2 hips, a revision was performed for aseptic loosening of the acetabular component 7 and 11 years after surgery. One additional cup was revised after 12 years during a femoral stem revision due to wear and matching problems, but was well fixed. The survival rate of the acetabular reconstruction technique was 94% (95% CI: 90-98%).

Bone graft incorporation after reconstruction of bony defects with impacted morselized bone graft. Histology of animals and patients.

The major problem in revision total hip surgery is the loss of bone stock, which is induced by various factors: the loosening process itself, osteolysis, infection and manipulations during removal of the prosthesis components and the cement. The instability of the implant leads to progressive bone loss and a vicious cycle is initiated in which a combined central and peripheral cavitary segmental defect may develop in the acetabulum. With the technique of impacted bone grafts and cement, it is possible to replace the loss of bone and to repair normal hip mechanics in combination with a standard hip prosthesis, achieving a long-lasting stable reconstruction. In this paper we present the histological data of patient-material and of various animal experiments to support this technique. From the results of this histology it could be concluded that in animals complete incorporation into a new bony structure took place. After incorporation the newly formed bone structure obeys Wolffs law. In the biopsies of patients, also an almost complete incorporation was found of the impacted morsellized bone graft. Base on the good results of the histology and based on the very good clinical follow-up data in the acetabulum of patients revised with this technique of impaction grafting, we strongly advocate the use of this technique in revision arthroplasty of the acetabulum.

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.

Acetabular reconstruction with impacted morcellized cancellous bone autograft and cemented primary total hip arthroplasty: a 10- to 17-year follow-up study.

During the period 1979 through 1986, 69 acetabular reconstructions in 63 patients were performed with the use of autologous morcellized bone-grafts because of acetabular bone stock loss. Nine cases (10 hips) were lost to follow-up. Eleven patients (12 hips) died <10 years after surgery; none had a revision. The results for the remaining 43 patients (47 hips) were reviewed at an average interval of 12.3 years (range, 10-17 years). No preoperative Harris hip score was available. The average Harris hip score at follow-up was 88 (range, 60-100). Radiographically, all grafts united. One hip developed a deep infection. Three other hips (6%) were revised because of aseptic loosening of the acetabular component. An additional 3 acetabular components were considered radiographic failures. Excluding the infected case, the overall survival rate of these acetabular reconstructions with a revision as endpoint was 94% at an average follow-up of 12.3 years. Reconstruction of acetabular bone stock loss with autologous morcellized bone-grafts is an attractive technique with a good potential for long-term success.

Impacted morsellized bone grafting and cemented primary total hip arthroplasty for acetabular protrusion in patients with rheumatoid arthritis: an 8- to 18-year follow-up study of 36 hips.

Between 1979 and 1989, we performed 36 primary total hip replacements in 31 rheumatoid arthritis patients with protrusio acetabuli. The deficient acetabulum was reconstructed with autologous morsellized bone grafts from the femoral head. 3 patients were lost to follow-up. 12 patients (13 hips) died within 8 years postoperatively, none had a revision. 16 patients (20 hips) were reviewed at an average follow-up of 12 (8-18) years. In 2 hips, a revision was performed for aseptic loosening of the acetabular component, 65 and 8 years after primary surgery, which means a 90% (95% CI: 77%-100%) survival rate at 12 years (Kaplan Meier analysis). This technique is a good option in cases with protrusio acetabuli due to rheumatoid arthritis.

Incorporation of morsellized bone graft under controlled loading conditions. A new animal model in the goat.

The aim of this study was to develop a new animal model in which we could assess the in vivo effects of mechanical stimuli in the incorporation process of impacted morsellized bone grafts. The subcutaneous pressure implant SPI was developed for use in the goat. This device can generate controlled loading conditions onto a fixed amount of bone graft in the distal femur. Twenty goats were divided into three groups: non-loaded, 2 or 4 MPa loads (1 Hz, 1 h/day). The goats were sacrificed after 3, 6 or 12 weeks. The results were documented by clinical observations, quantitative bone density from QCT-scanning and histomorphometry. Nine post-mortem knee specimens were prepared in a similar manner to the experimental knees to determine the reproducibility and mechanical stability of the grafting method. Three goats were lost due to complications, the others functioned clinically well. Histology showed invasion of the bone graft by a front of vascular fibrous tissue after which osteoclasts resorbed the dead bone graft, followed by woven bone apposition on the graft remnants. At 12 weeks the loaded grafts had transformed into a vital trabecular structure. QCT bone density measurements revealed persistently high densities in the 12-weeks 4 MPa specimens, but reduced densities in the 2 MPa and non-loaded specimens. Morphometrically, the mineralising surface was larger in the 4 MPa group (P = 0.02) and the incorporation and remodelling processes had advanced more rapidly in the 2 MPa specimens (P = 0.04). Although the numbers investigated in this study in each group were low, statistical differences were found in the amount of graft left after incorporation and in the apposition rate of the new bone. In the future this model will be used to study the incorporation potential of different types of bone graft and bone graft substitutes.

Role of growth factors in the incorporation of unloaded bone allografts in the goat.

Revision of a failed total joint replacement often demands bone grafting methods to restore deficient bone stock. However, impaired allograft incorporation can be the result of inadequate host or graft properties. The stimulation of bone healing with growth factors could provide a new approach to deal with this problem. The repeated sampling bone chamber was used in the goat to investigate the properties of bone allografts enriched with transforming growth factor-beta, recombinant human bone morphogenetic protein-2, and basic fibroblastic growth factor under unfavorable vascular and nonloaded conditions. Ten goats each had three bone chambers implanted in the medial proximal tibia. Different carrier allograft bone preparations were used for each growth factor based on convention and previously reported results. The period between implantation and chamber harvest was 8 weeks. The concentrations of the growth factors used was 0, 1, or 10 micrograms of transforming growth factor-beta 2, 0, 1, or 5 micrograms of bone morphogenetic protein-2, and 0, 40, 200 ng of basic fibroblastic growth factor. The specimens were analyzed histomorphometrically for the amount of soft tissue ingrowth, bone ingrowth, and the number of osteoclasts. In all specimens, a resorption front grew into the graft followed by fibrovascular tissue and, in some instances, bone. In the 5 micrograms of bone morphogenetic protein-2 specimens, larger amounts of soft tissue and woven bone were present, whereas in the specimens that received 10 micrograms of transforming growth factor-beta 2, there was a decrease in the amount of tissue and bone ingrowth. Two hundred nanograms of basic fibroblastic growth factor had a negative effect on soft tissue formation but increased the amount of vascular elements containing erythrocytes. The number of osteoclasts was higher in the 5-microgram bone recombinant human morphogenetic protein-2 specimens. In the clinical arena with absence of good perigraft vascularization and loading, bone morphogenetic protein-2 may have a strong stimulatory effect on bone graft incorporation.

[Surgical techniques used in the revision of hip prostheses]. / Operatieve technieken bij het reviseren van heupprothesen.

The most common cause of failure of cemented and cementless total hip arthroplasties is aseptic loosening, a slow but progressive process that often results in loss of bone stock. The diagnosis of loosening of the prosthetic component is difficult and depends mainly on migration and change in position of the prosthesis and the appearance of clear zones around the prosthesis on X-ray photographs. The key problem in revision surgery is how to manage the periprosthetic bone loss. Controversy exists about the best treatment for bone stock defects. The various techniques are directed at restoration of the hip mechanics, restoration of the defects in the osseous wall, replacement of the resorbed bone and thus restoration of the functional stability of the joint.

Viability of the acetabular bone bed at revision surgery following cemented primary arthroplasty.

Loosening of total hip replacements is often associated with severe loss of periprosthetic bone. The notion exists that the remaining bone is sclerotic, avascular, and displays little osteogenic activity, and that it therefore potentially compromises the revitalization of bone grafts used to restore bony defects. To verify this opinion we studied the bone characteristics in acetabular bone biopsies taken at primary total hip arthroplasty (PTH) and revision total hip arthroplasty (RTH) for a cemented PTH. In 6 PTH patients and in 10 RTH patients, acetabular bone biopsies were taken from the roof, the center, and the lower rim of each acetabulum. Specimens were evaluated by light microscopy and histomorphometrically measured for specimen size, bone area, perimeter, active osteoid perimeter, number of vessels, and osteoclasts. The vascularity and vitality appeared to be comparable in the RTH and PTH bone biopsies. However, the trabecular organization of the RTH bone differed from that of the PTH biopsies. In the PTH biopsies, the trabeculae were running perpendicular to the subchondral bone layer, whereas in the RTH biopsies the layers of bone were oriented parallel to the implant surface. There was abundant remodeling activity in the RTH bone, with large quantities of active osteoid and osteoclasts. These histologic parameters differed, but not statistically significant, from the PTH biopsies. In conclusion, we found that at revision, the acetabular bone was viable with sufficient vascularity and remodeling activity to provide an acceptable recipient host bone bed for revision surgery combined with bone grafting.

Acetabular reconstruction with impacted morsellised cancellous bone graft and cement. A 10- to 15-year follow-up of 60 revision arthroplasties.

We report a long-term review of 60 acetabular components revised using impacted, morsellised bone allografts and a cemented polyethylene cup. The acetabular defects were cavitary (37) or combined (23). Follow-up was for a mean 11.8 years (10 to 15). Further revision was needed in five hips, two for septic and three for aseptic loosening. The overall survival rate at 11.8 years was 90%; excluding the septic cases it was 94%. Acetabular reconstruction with impacted morsellised cancellous grafts and cement gives satisfactory long-term results.