Background. Impaction bone grafting (IBG) using a circumferential metal mesh is one of the options that allow restoration of the femoral bone stock and stability of the implant in hip arthroplasty. Here we examined the clinical and radiographic outcome of this procedure with a cemented stem and analyzed experimentally the initial stability of mesh–grafted bone–cemented stem complexes. Methods. We retrospectively reviewed 6 hips (6 patients) that had undergone femoral revisions with a circumferential metal mesh, impacted bone allografts, and a cemented stem. The mean follow-up period was 2.9 years (range, 1.4–3.8 years). Hip joint function was evaluated with the Japanese Orthopaedic Association hip score, and radiographic changes were determined from radiographs. The initial resistance of cemented stem complexes to axial and rotational force was measured in a composite bone model with various segmental losses of the proximal femur. Results. The hip score improved from 50 (range, 10–84) preoperatively to a mean of 74 (range, 67–88) at the final follow-up. The overall implant survival rate was 100% at 4 years when radiological loosening or revision for any reason was used as the endpoint. No stem subsided more than 3 mm vertically within 1 year after implantation. Computed tomography showed reconstitution of the femoral canal in a metal mesh. In mechanical analyses, there was no influence on the stem stability to axial compression during the repeated axial compression test between IBG reconstruction rates. On the other hand, for IBG reconstruction rate of 66.7%, grafted bone-Sawbone juntion was buckled under the axial breaking force. In contrast, under rotational load, the rotation angles of the stainless mesh were strongly affected by the IBG reconstruction rate. Conclusions. The short-term results show good outcomes for reconstruction of proximal bone loss with impaction bone allografts and a circumferential mesh. The procedure should be applied in cases where the circumferential proximal bone loss is less than half of the stem length implanted

Introduction. Segmental defects of the femur present a major problem during revision hip arthroplasty. In particular, calcar segmental defects may compromise initial and long-tem femoral stem stability. Objective. The objective of the present study is to assess mid-term clinical and radiographic follow-up results at least two years after femoral revision comprising reconstruction for calcar segmental defect using metal wire mesh and impacted morcellised allograft. Methods. We performed 26 femoral revisions with calcar reconstruction in 24 patients between 2002 and 2010. The average age was 69.7 years, and the average follow-up period was 5 years and 1 month. All surgeries were performed using a cemented polished collarless tapered stem. The segmental calcar defect was reconstructed with metal wire mesh with doubled stainless wires. Large sized morcellised cancellous allograft was tightly impacted into the cavity between the phantom stem and the metal wire mesh. Nineteen hips were reconstructed with impaction bone grafting of the femur, and 7 hips with cement-in-cement technique except for the reconstructed calcar region.ã�� For clinical assessment, Merle d'Aubigné and Postel hip scores were recorded. For radiological assessment, antero-posterior hip radiographs were analyzed pre-operatively, and post-operatively at one month, 6 months and every 6 months thereafter. Clear lines around the femoral component using Gruen zone classification, stem subsidence in cement mantle, and change of stem axis were recorded. Kaplan-Meier survival analyses were performed with any re-operation of the femoral component or aseptic loosening as end points. In one case, the histological appearance of a biopsy specimen of the most proximal part of the reconstructed calcar, which was obtained at a later surgery for infection at 4 years after the revision, is described. Results. For clinical assessment, the mean Merle d'Aubigné and Postel hip scores improved from 10.4 points before the operation to 14.7 points at the final follow-up. For radiological assessment, no clear lines at the cement-bone interface and no stem axis changes were detected. Twenty-five of 26 hips showed less than 2 mm of stem subsidence at the final follow-up and one hip showed 2.2 mm stem subsidence. Both hips of one female patient underwent a one stage stem exchange because of an infection that occurred 48 months after revision. No cases showed aseptic loosening up to and including the last follow-up. The Kaplan-Meier survival analysis revealed that the survival rate at five years after revision was 88.0% with any type of re-operation on the femoral side as the endpoint and 100% with aseptic stem loosening as the endpoint, respectively. A biopsy specimen taken from the most proximal part of the reconstructed calcar region at 4 years after surgery in the infected case showed almost complete regeneration of viable bone with normal marrow spaces with partially formed granulation tissue. Conclusion. Reconstruction using metal wire mesh and tightly impacted morcellised allograft is a favorable method for the correction a calcar segmental defect. The procedure is simple and reliable, achieving initial and mid-term stem stability even for femurs with a complete calcar defect

Purpose of the study: The incidence of revision hip arthroplasty is increasing. In order to overcome certain problems related to loss of femoral bone stock, an original technique was developed combining fragmented allograft material and a metallic mesh with a non filling stem cemented distally in a healthy zone to ensure stability.

Materials and Methods: The clinical data (Postel-Merle-d’Aubigné, PMA score) and radiographic findings (implant migration, loss of bone stock using the SOFCOT and PAPROSKY classification, quality of cementing, filling, and graft aspect, graft lysis, periprosthetic lucency, final aspect of the graft) were collected retrospectively. The operation and the technical difficulties and intraoperative complications were noted.

Results: We report a series of 32 hips treated with this technique and having a mean follow-up of 12.5 years (range 8–20 years). The population studied had particularly significant bone loss (78.2% SOFCOT stage 3 and4). These hips underwent revision for aseptic loosening. The implantation technique required a femoral window in 39.1%. Preventive cerclage was often used (39.1%) but did not prevent fracture or missinsertion in 30.4%. The PMA score improved significantly from 10.6 (7–18) preoperatively to 17 (12–18) at last follow-up. Radiologically, femoral bone regeneration at last follow-up had an aspect of corticalisation in 63.6% of hips, and of cancellous trabeculation in 36.4%. Femoral implant survival was 100% at eight years, and 92.8±6.88% at mean follow-up of 12.5 years. There was only one revision at eleven years for secondary osteolysis related to polyethylene wear in a very active subject implanted before the age of 50 years.

Discussion: The clinical and radiographic results are very satisfactory for this series of femoral revisions using an impacted fragmented graft material and with the longest follow-up reported in the literature. Distal fixation limited migration observed when the stem is entirely cemented in the graft, but did not affect reconstruction which demonstrated long-term stability. This technique, initiated in 1986 without a specific instrument set, had now demonstrated its long-term reliability. The only problem is the length of the operation and the complications related to femoral preparation.

The last two decades have seen remarkable technological advances in total hip arthroplasty (THA) implant design. Porous ingrowth surfaces and highly crosslinked polyethylene (HXLPE) have been expected to dramatically improve implant survivorship. The purpose of the present study was to evaluate survival of contemporary cementless acetabular components following primary THA. 16,421 primary THAs performed for osteoarthritis between 2000 and 2019 were identified from our institutional total joint registry. Patients received one of 12 contemporary cementless acetabular designs with HXLPE liners. Components were grouped based on ingrowth surface into 4 categories: porous titanium (n=10,952, mean follow-up 5 years), porous tantalum (n=1223, mean follow-up 5 years), metal mesh (n=2680, mean follow-up 6.5 years), and hydroxyapatite (HA) coated (n=1566, mean follow-up 2.4 years). Kaplan-Meier analyses were performed to assess the survivorship free of acetabular revision. A historical series of 182 Harris-Galante-1 (HG-1) acetabular components was used as reference. The 15-year survivorship free of acetabular revision was >97% for all 4 contemporary cohorts. Compared to historical control, porous titanium (HR 0.06, 95% CI 0.02–0.17, p<0.001), porous tantalum (HR 0.09, 95%CI 0.03–0.29, p<0.001), metal mesh (HR 0.11, 95%CI 0.04–0.31, p<0.001), and HA-coated (HR 0.14, 95%CI 0.04–0.48, p=0.002) ingrowth surfaces had significantly lower risk of any acetabular revision. There were 16 cases (0.1%) of acetabular aseptic loosening that occurred in 8 (0.07%) porous titanium, 5 (0.2%) metal mesh, and 3 (0.2%) HA-coated acetabular components. 7 of the 8 porous titanium aseptic loosening cases occurred in one known problematic design. There were no cases of aseptic loosening in the porous tantalum group. Modern acetabular ingrowth surfaces and HXLPE liners have improved on historical results at the mid-term. Contemporary designs have extraordinarily high revision-free survivorship, and aseptic loosening is now a rare complication. At mid-term follow-up, survivorship of contemporary uncemented acetabular components is excellent and aseptic loosening occurs in a very small minority of patients

Containment of bone defects is one of the main requisites for using the bone impaction grafting technique. When the proximal femur is absent, circumferential meshes in combination with impacted bone allografts and long stems could be an alternative method. However, the initial stability of this femoral stems has not been evaluated and we were not able to find any series in the literature that includes a group of patients treated with this method. This study has two purposes: one is to analyze the initial resistance in vitro to axial and rotational forces of a fresh frozen bovine model with a complete loss of the proximal femur reconstructed with a circumferential metal mesh containing impacted bone allografts and a long polished cemented stem. The second is to present the short-term clinical and radiographic evaluation in a group of patients with massive bone loss of the proximal femur that were reconstructed with this method. Four femurs with an 8 cm proximal bone defect were reconstructed with a circumferential metal mesh, impacted bone grafts and a cemented long stem (group 1). Results were compared with 4 cases presenting an intact proximal femur in which the same stem was implanted (group 2). Thirteen patients with complete massive proximal femoral bone defects (average 12 cm long) were reconstructed with a circumferential metal mesh, impacted bone allografts and a long cemented stem (average 217 cm long). Failure mode was characterized by subsidence under axial load in group one at 617 kg and by periprosthetic fracture in control group at 1335 kg. Under rotational load, group 1 femurs failed at the cement interface at an average of 79 kg and the intact femurs presented a fracture at an average of 260 kg. At 25 months follow-up, 6 patients had to be reoperated. We observed 2 fractures of the metal mesh at 31 and 48 months in cases reconstructed with a Charnley stem that did not by pass the mesh. Three patients presented one dislocation that needed open reduction in 2 cases. Two acute deep infections were treated with debridement, antibiotics and component retention. This model presented a 50% resistance to axial load and 30% resistance to rotational load compared to an intact femur with the same implant. However, this resistance is by far higher than the physiologic load occurring in a normal femur during gait. Although the incidence of complications in this patients was high, this was related to the complexity of the cases. Failures of the system were not observed except in the 2 cases presenting technical defects. This experimental initial stability and early clinical as well as radiographic results encourage the use of circumferential meshes to contain impacted bone allografts combined with long cemented stems in complex revision hip surgery

Bone impaction grafting of the femur is associated with more complications when segmental defects are present. The effect of segmental defect repair on initial stem stability was studied in an in vitro study with fresh frozen goat femora. A standardized medial segmental defect was reconstructed using a cortical strut or a metal mesh. As controls we used intact femora and femora with a non-reconstructed defect. In all four groups impacted bone grafting was performed in combination with a cemented Exeter stem. Each group contained five femora. Reconstructions were dynamically loaded up to 1500N. Migration was measured with Roentgen Stereo-photogrammetric Analysis. All cases with a non-reconstructed segmental defect failed into excessive varus rotation. None of the femora with a reconstructed defect failed. Cortical struts and metal meshes were equally effective in creating a stable stem construction (varus rotation 2.89±2.27 and 2.27±0.57, respectively). Reconstructions with a metal mesh were more reproducible, although the obtained stability was significantly lower (p< 0.01) when compared to impaction grafting in an intact femur (varus rotation 0.58±0.36). Besides, structural grafts may negatively influence the revascularization of the underlying impacted grafts in contrast to an open wire mesh. So, an in vivo study of 12 goats was done. A standardized medial wall defect was reconstructed with a strut or a mesh in six goats per group. In all femora impaction grafting was performed in combination with a cemented Exeter stem. After six weeks the femora were harvested. A high rate of peri-prosthetic fractures was found (43% and 29% for the strut and mesh groups, respectively). Histological and micro-radiological examination showed different revascularization patterns for both reconstruction techniques. In the strut group revascularized graft was found at the edges of the defect. In the mesh group fibrous tissue and blood vessels penetrated through the mesh and a superficial zone of revascularized grafts was found. Segmental defect reconstruction with a strut reduced the amount of revascularized grafts medially behind the strut (p=0.004). This may interfere with the stability of the stem in the first period after surgery and the incorporation of the impacted grafts on the long-term. We would recommend segmental defect reconstruction with a mesh. A regime of unloading and long-stem prostheses should be used, irrespective of the reconstruction technique

Femoral revision after cemented total hip arthroplasty (THA) might include technical difficulties, following essential cement removal, which might lead to further loss of bone and consequently inadequate fixation of the subsequent revision stem. Bone loss may occur because of implant loosening or polyethylene wear, and should be addressed at time of revision surgery. Stem revision can be performed with modular cementless reconstruction stems involving the diaphysis for fixation, or alternatively with restoration of the bone stock of the proximal femur with the use of allografts. Impaction bone grafting (IBG) has been widely used in revision surgery for the acetabulum, and subsequently for the femur in Paprosky defects Type 1 or 2. In combination with a regular length cemented stem, impaction grafting allows for restoration of femoral bone stock through incorporation and remodeling of the proximal femur. Cavitary bone defects affecting the metaphysis and partly the diaphysis leading to a wide femoral canal are ideal indications for this technique. In case of combined segmental-cavitary defects a metal mesh is used to contain the defect which is then filled and impacted with bone grafts. Cancellous allograft bone chips of 2 to 4 mm size are used, and tapered into the canal with rods of increasing diameters. To impact the bone chips into the femoral canal a dummy of the dimensions of the definitive cemented stem is inserted and tapped into the femur to ensure that the chips are firmly impacted. Finally, a standard stem is implanted into the newly created medullary canal using bone cement. To date several studies from Europe have shown favorable results with this technique, with some excellent long-term results reported. Advantages of IBG include the restoration of the bone stock in the proximal femur, the use of standard length cemented stems and preserving the diaphysis for re-revision. As disadvantages of the technique: longer surgical time, increased blood loss and the necessity of a bone bank can be mentioned

Using the Mayo Clinic definition (>62mm in women and >66mm in men), the “jumbo acetabular component” is the most successful method for acetabular revisions now, even in hips with severe bone loss. There are numerous advantages: surface contact is maximised; weight-bearing is distributed over a large area of the pelvis; the need for bone grafting is reduced; and usually, hip center of rotation is restored. The possible disadvantages of jumbo cups include: may not restore bone stock; may ream away posterior column or wall; screw fixation required; the possibility of limited bone ingrowth and late failure; and a high rate of dislocation due to acetabular size:femoral head ratio. The techniques for a successful jumbo revision acetabular component involve: sizing-“reaming” of the acetabulum, careful impaction to achieve a “press-fit”, and multiple screw fixation. We recommend placement of an ischial screw in addition to dome and posterior column screw fixation. Cancellous allograft is used for any cavitary defects. The contra-indications for a jumbo acetabular cup are: pelvic dissociation; inability to get a rim fit; and inability to get screw fixation. If stability cannot be achieved with the jumbo cup alone, then use of augment(s), bulk allograft, or cup-cage construct should be considered. Using titanium fiber-metal mesh components, we reported the 15-year survival of 129 revisions. There was 3% revision for deep infection and only 3% revision for aseptic loosening. There were 13 reoperations for other reasons: wear, lysis, dislocation, femoral loosening, and femoral fracture fixation. The survival was 97.3% at 10 years, but it dropped to 82.8% at 15 years. Late loosening of this fiber metal mesh component is likely related to polyethylene wear and loss of fixation. Dislocation is the most common complication of jumbo acetabular revisions, approximately 10%, and these are multifactorial in etiology and often require revision. Based on our experience, we now recommend use of an acetabular component with an enhanced porous coating (tantalum), highly crosslinked polyethylene, and large femoral heads or dual mobility for all jumbo revisions

Introduction. Hydroxyapatite and poly-L-lactide (HA/PLLA) composites are osteoconductive and biodegradable. They have already been used clinically to treat fractured bones by inducing osteosynthesis and serving as the bone filling material. During revision of total hip arthroplasty, we have grafted bone onto the bone defect and covered it with an HA/PLLA mesh instead of using a metal mesh on the non-load bearing portion of the cup (Figure 1). However, whether the interface between the HA/PLLA and the titanium alloy cup was stable remains unclear. Objectives. The purpose of this study was to determine and compare the histological osteoconductivity and osteoinductivity of HA/PLLA and titanium alloy. Methods. Semicylindrical samples (diameter: 3 mm; height: 5 mm) were fabricated from a composite unsintered-HA/PLLA containing 40% fine HA particles and from titanium alloy (Ti-6AL-4V). These two samples were combined to form one cylinder (Figure 2). Defects 3 mm in diameter were drilled into both femoral condyles of nine Japanese white rabbits, and the samples were implanted by press fitting. The rabbits were euthanized at 2, 4, 8, and 25 weeks after implantation, and undecalcified ground samples were prepared. New bone formation was examined histologically using Toluidine blue and Villanueva Goldner stains. Results. New bone formation was observed around the sample at 4 weeks, and the amount increased by 8 weeks. In addition, partial remodeling of the trabecular bones and absorption of the HA/PLLA were found at 25 weeks. Small amounts of new bone formation were found at 4 weeks between the HA/PLLA and titanium alloy materials (Figure 3: Toluidine blue stain), and the amount increased at 8 and 25 weeks. The HA/PLLA had been slightly absorbed and new bone was formed in the gap, which was close to the border between the materials, at 25 weeks. However, the amount of absorption was limited, and no new bone was found in samples where the materials were firmly in contact. Conclusions. HA/PLLA was only slight absorbed at 25 weeks, suggesting that it was stable in vivo and has good osteoconductive and osteoinductive properties. No new bone was found in the regions where the sample was stable and had no gaps between the HA/PLLA and titanium alloy, probably because there was no space for new bone to form in those regions. In contrast, new bone formation was found in gaps of more than 20 μm. Clinically, many gaps likely exist, allowing new bone formation to occur even in a stable implant. This may stabilize the HA/PLLA and titanium alloy materials for longer times. As expected, the HA/PLLA and titanium alloy were mostly stablein vivo

Using the Mayo Clinic definition (>62mm in women and >66mm in men), the “jumbo acetabular component” is the most commonly used method for acetabular revisions now. There are numerous advantages: surface contact is maximised; weight-bearing is distributed over a large area of the pelvis; the need for bone grafting is reduced; and usually, hip center of rotation is restored. The possible disadvantages, or caveats, of jumbo cups include: may not restore bone stock; may ream away posterior column or wall; screw fixation required; the possibility of limited bone ingrowth and late failure; and a high rate of dislocation due to acetabular size:femoral head ratio. The techniques for a successful jumbo revision acetabular component involve: sizing-“reaming” of the acetabulum, careful impaction to achieve a “press-fit”, and multiple screw fixation. We recommend placement of an ischial screw in addition to dome and posterior column screw fixation. Cancellous allograft is used for any cavitary defects. The contraindications for a jumbo acetabular cup are: pelvic dissociation; inability to get a rim fit; inability to get screw fixation; and the presence of <50% living host bone. If stability cannot be achieved with the jumbo cup alone, then use of augment(s), bulk allograft, or cup-cage construct should be considered. Our results with the jumbo acetabular cups in revision arthroplasty have been reported. Using predominantly titanium fiber-metal mesh components, we reported the 15-year survival of 129 revisions. There was 3% revision for deep infection and only 3% revision for aseptic loosening. There were 13 reoperations for other reasons: wear, lysis, dislocation, femoral loosening, and femoral fracture fixation. The survival was 97.3% at 10 years, but it dropped to 82.8% at 15 years. Late loosening of this fiber metal mesh component is likely related to polyethylene wear and loss of fixation. Dislocation is the most common complication of jumbo acetabular revisions, approximately 10%, and these are multifactorial in etiology and often require revision. Based on our experience, we now recommend use of an acetabular component with an enhanced porous coating (tantalum), highly cross-linked polyethylene, and large femoral heads for all jumbo revisions

Femoral revision in cemented THA might include some technical difficulties, based on loss of bone stock and cement removal, which might lead to further loss of bone stock, inadequate fixation, cortical perforation or consequent fractures. Femoral impaction grafting, in combination with a primary cemented stem, allows for femoral bone restoration due to incorporation and remodeling of the allograft bone by the host skeleton. Historically, it has been first performed and described in Exeter in 1987, utilizing a cemented tapered polished stem in combination with morselised fresh frozen bone grafts. The technique was refined by the development of designated instruments, which have been implemented by the Nijmegen group from Holland. Indications might include all femoral revisions with bone stock loss, while the ENDO-Klinik experience is mainly based on revision of cemented stems. Cavitary bone defects affecting meta- and diaphysis leading to a wide or so called “drain pipe” femora, are optimal indications for this technique, especially in young patients. Contraindications are mainly: septical revisions, extensive circumferential cortical bone loss and noncompliance of the patient. Generally the technique creates a new endosteal surface to host the cemented stem by reconstruction of the cavitary defects with impacted morselised bone graft. This achieves primary stability and restoration of the bone stock. It has been shown, that fresh frozen allograft shows superior mechanical stability than freeze-dried allografts. Incorporation of these grafts has been described in 89%. Technical steps include: removal of failed stem and all cement, reconstruction of segmental bone defects with metal mesh (if necessary), preparation of fresh frozen femoral head allografts with bone mill, optimal bone chip diameter 2 – 5 mm, larger chips for the calcar area (6 – 8 mm), insertion of an intramedullary plug including central wire, 2 cm distal to the stem tip, introduction of bone chips from proximal to distal, impaction started by distal impactors over central wire, then progressively larger impactors proximal, insertion of a stem “dummy” as proximal impactor and space filler, removal of central wire, retrograde insertion of low viscosity cement (0.5 Gentamycin) with small nozzle syringe, including pressurization, insertion of standard cemented stem. The cement mantle is of importance, as it acts as the distributor of force between the stem and bone graft and seals the stem. A cement mantle of at least 2 mm has shown favorable results. Originally the technique is described with a polished stem. We use standard brushed stems with comparable results. Postoperative care includes usually touch down weight bearing for 6–8 weeks, followed by 4–6 weeks of gradually increased weightbearing with a total of 12 weeks on crutches. Survivorship with a defined endpoint as any femoral revision after 10 year follow up has been reported by the Exeter group being over 90%. While survivorship for revision related to aseptic loosening being above 98%. Within the last years various other authors and institutions reported similar excellent survivorships, above 90%. In addition a long term follow up by the Swedish arthroplasty registry in more than 1180 patients reported a cumulative survival rate of 94% after 15 years. Impaction grafting might technically be more challenging and more time consuming than cement free distal fixation techniques. It, however, enables a reliable restoration of bone stock which might become important in further revision scenarios in younger patients

Femoral revision in cemented THA might include some technical difficulties, based on loss of bone stock and cement removal, which might lead to further loss of bone stock, inadequate fixation, cortical perforation or consequent fractures. Femoral impaction grafting, in combination with a primary cemented stem, allows for femoral bone restoration due to incorporation and remodelling of the allograft bone by the host skeleton. Historically it has been first performed and described in Exeter in 1987, utilizing a cemented tapered polished stem in combination with morselised fresh frozen bone grafts. The technique was refined by the development of designated instruments, which have been implemented by the Nijmegen group from Holland. Indications might include all femoral revisions with bone stock loss, while the Endo-Clinic experience is mainly based on revision of cemented stems. Cavitary bone defects affecting meta- and diaphysis leading to a wide or so called “drain pipe” femora, are optimal indications for this technique, especially in young patients. Contraindications are mainly: septical revisions, extensive circumferential cortical bone loss and noncompliance of the patient. Generally, the technique creates a new endosteal surface to host the cemented stem by reconstruction of the cavitary defects with impacted morselised bone graft. This achieves primary stability and restoration of the bone stock. It has been shown, that fresh frozen allograft shows superior mechanical stability than freeze-dried allografts. Incorporation of these grafts has been described in 89%. Technical steps include: removal of failed stem and all cement, reconstruction of segmental bone defects with metal mesh (if necessary), preparation of fresh frozen femoral head allografts with bone mill, optimal bone chip diameter 2–5 mm, larger chips for the calcar area (6–8 mm), insertion of an intramedullary plug including central wire, 2 cm distal the stem tip, introduction of bone chips from proximal to distal, impaction started by distal impactors over central wire, then progressive larger impactors proximal, insertion of a stem “dummy” as proximal impactor and space filler, removal of central wire, retrograde insertion of low viscosity cement (0.5 Gentamycin) with small nozzle syringe, including pressurization, and insertion of standard cemented stem. The cement mantle is of importance, as it acts as the distributor of force between the stem and bone graft and seals the stem. A cement mantle of at least 2 mm has shown favorable results. Post-operative care includes usually touch down weightbearing for 6–8 weeks, followed by 4–6 weeks of gradually increased weightbearing with a total of 12 weeks on crutches. Relevant complications include mainly femoral fractures due to the hardly impacted allograft bone. Subsidence of tapered polished implants might be related to cold flow within the cement mantle, however, could also be related to micro cement mantle fractures, leading to early failure. Subsidence should be less than 5 mm. Survivorship with a defined endpoint as any femoral revision after 10-year follow up has been reported by the Exeter group being over 90%, while survivorship for revision as aseptic loosening being above 98%. Within the last years various other authors and institutions reported about similar excellent survivorships, above 90%. In addition, a long-term follow up by the Swedish arthroplasty registry in more than 1180 patients reported a cumulative survival rate of 94% after 15 years. Impaction grafting might technically be more challenging and more time consuming than cement-free distal fixation techniques. It, however, enables a reliable restoration of bone stock which might especially become important in further revision scenarios in younger patients

Purpose. The purpose of the present study is to assess 5–10 years' follow-up results after acetabular impaction bone grafting (IBG) in primary cemented total hip arthroplasty (THA) for cases with acetabular bone defect. Patients and methods. We performed 36 primary cemented THA with acetabular IBG in 33 patients between November 2004 and May 2009. As one patient died due to unrelated disease at 6 months after the surgery, 35 hips of 32 patients were included in this study. The average age at the surgery was 62.4 years, and the average follow-up period was 7.9 years (5–10 years). Diagnoses were osteoarthritis due to acetabular dysplasia in 28 hips (26 patients), Rheumatoid arthritis (RA) in 4 hips (3 patients), rapidly destructive coxopathy (RDC) in 1 hip (1 patient), idiopathic acetabular protrusion in 1 hip (1 patient), and acromegaly in 1 hip (1 patient). For clinical assessment, the Merle d'Aubigné and Postel hip score was assessed and degree of post-operative improvement was classified according to their method as very great improvement, great improvement, fair improvement, and failure. Perioperative complications were also recorded. Acetabular bone defects were assessed at the surgery and categorized using AAOS acetabular bone defect classification system. For radiological assessment, anteroposterior radiographs of the bilateral hip joints were analyzed preoperatively and post-operatively. Radiolucent lines (RLL) of more than 2 mm around the acetabular components were assessed using the DeLee and Charnley zone classification. Acetabular component loosening was assessed according to the Hodgkinson et al. classification system, and type 3 (complete demarcation line) and type 4 (migration) were classified as “loosening”. Results. The mean Merle d'Aubigné and Postel hip score improved from 9.8 points before the operation to 15.9 points at the final follow-up. Degree of post-operative improvement was assessed as “very great” in 11 hips, “great” in 23 hips and “fair” in 1 hip. Dislocation, DVT, and infection were recorded in 1 hip, 1 hip, and 1 hip, respectively. Re-operation was performed for the acute infection (without loosening) case at 5.3 years after the primary THA. Acetabular bone defects were classified as segmental defect (AAOS type I) in 29 hips, cavitary defect (AAOS type II) in 3 hips and combined segmental and cavitary defect (AAOS type III) in 3 hips. Metal meshes were used for segmental defects of 29 AAOS type I hips and 2 AAOS type III hips, and for medial wall defect of 1 AAOS III hip. On radiographic assessment, no metal device breakage was detected during the follow-up period. There were no clear lines around the cup and all cups were assessed as stable at the final follow-up. Conclusion. Acetabular impaction bone grafting in primary cemented THA is technically demanding procedure. However, postoperative functional improvement is remarkable and stable radiographic findings were achievable independent from original diagnoses. This procedure is one of useful options to restore acetabular bone deficiency in cemented primary THA for cases with acetabular bone defect

Aims: The effects of bone graft washing and bone graft particle size on initial cup stability in an acetabular model were studied. Methods: From fresh human femoral heads large (8–12 mm) and small (2–4) grafts were produced. Four different groups were tested; large washed, large unwashed, small washed and small unwashed. An AAOS type 3 combined defect was reconstructed in a synthetic acetabular model using a metal mesh and screws. Bone grafts were impacted in a standardized way using a hammer and metal impactors. Cement was pressurized and a PE cup was inserted. Cups were dynamically loaded with 1500 N and 3000 N for 15 minutes using an MTS-device, RSA was used to calculate 3-D cup migrations. Next a lever-out test of the cup was done in a displacement (16¡/minute) controlled test. After testing CT scans of the cups were made to quantify cement layer roughness, as a measurement of cement penetration. Results: Cups reconstructed with large washed bone grafts migrated signiþcantly less during mechanical compression and withstood signiþcantly higher lever-out moments. Washing improved cup stability for both small and large grafts, however only signiþcantly for the larger bone grafts. A signiþcantly higher cement penetration depth was found for all large bone grafts, washing did not inßuence cement penetration depth. Discussion: For acetabular revisions with bone impaction grafting we recommend to use large washed bone grafts

Purpose. The purpose of this study is to compare using a novel cementing technique with hydroxyapatite granules at bone-cement interface with using the 3. rd. cementing technique on the acetabular component. Patients and Methods. Between 2005 and 2007, we performed 54 primary cemented THAs using the 3. rd. generation cementing technique with hydroxyapatite granules at bone-cement interface (Group A: 21 hips) or without them (Group B: 33 hips) in 49 patients with dysplastic hip (6 males, 43 female; mean age at operation, 67 years; age range, 48–84 years). Mean follow up was 5.3 years (range, 2.3–7.1 years), with none of the patients lost to follow up. According to Crowe's classification, subluxation was Group I in 31 hips, group II in 11 hips, group III in 8 hips, and group IV in 4 hips. We used Exeter flanged cup, Exeter stem with a 22-mm diameter metal head (Stryker, Benoist Girard, France) and Simplex-P bone cement (Stryker, Limerick, Ireland) in all hips. A posterolateral approach was performed for all patients. Bone graft was performed 25 hips (block bone graft: 11 hips; impaction bone grafting with a metal mesh: 13 hips) from autogeneic femoral head. Our 3. rd. cementing technique is to make multiple 6-mm anchor holes, to clean the the host acetabular bed with pulse lavage, to dry it with hydrogen peroxide and to use Exeter balloon pressurizer and Exeter flanged cup. Results. The outcomes showed no aseptic loosening and radiological loosening at final follow up. Radiolucent line around the acetabular component was present 14% in Group A and 42% in Group B at 4 years after operation. Kaplan-Meier survivorship analysis of appearance of a radioluent line around the acetabuler component as the end point was 85.7% on group A was significant higher than 57.6% on group B at 4 years. Conclusion. Radiolucent line around cemented acetabular component in total hip arthroplasty using the 3. rd. cementing technique with hydroxyapatite granules at bone-cement interface was significant higher survivorship than them of the 3. rd. cementing technique at 4 years after operation. We suggest that improved novel cementing technique will lead to greater long-term success outcomes of the acetabular component

Background: Bacteria form a biofilm on the surface of orthopaedic devices, causing persistent and infection. Little is known about biofilms formation on bone grafts and bone substitutes. We analyzed various representative materials regarding their propensity for biofilm formation caused by Staphylococcus aureus. Methods: As bone graft beta-tricalciumphosphate (b-TCP, CyclOsTM) and as bone substitute a tantalum metal mesh (trabecular metalTM) and PMMA (Pala-cosTM) were investigated. As test organism S. aureus (strain ATCC 29213) was used. Test materials were incubated with bacterial solution of 105 colony-forming units (cfu)/ml at 37°C for 24 h without shaking. After 24 h, the test materials were removed and washed 3 times in normal saline, followed by sonication in 50 ml Ringer solution at 40 kHz for 5 minutes. The resulting sonication fluid was plated in aliquots of 0.1 ml onto aerobe blood agar with 5% sheep blood and incubated at 37°C with 5% CO2 for 24 h. Then, bacterial counts were enumerated and expressed as cfu/ml. All experiments were performed in triplicate to calculate the mean ± standard deviation. The Wilcoxon test was used for statistical calculations. Results: The three investigated materials show a differing specific surface with b-TCB> trabecular metal> PMMA per mm2. S. aureus formed biofilm on all test materials as confirmed by quantitative culture after washing and sonication. The bacterial counts in sonication fluid (in cfu/ml) were higher in b-TCP (5.1 x 106 ± 0.6 x 106) and trabecular metal (3.7 x 106 ± 0.6 x 106) than in PMMA (3.9 x 104 ± 1.8 x 104), p< 0.05. Conclusion: Our results demonstrate that about 100-times more bacteria adhere on b-TCP and trabecular metal than on PMMA, reflecting the larger surface of b-TCP and trabecuar metal compared to the one of PMMA. This in-vitro data indicates that bone grafts are susceptible to infection. Further studies are needed to evaluate efficient approaches to prevent and treat infections associated with bone grafts and substitutes, including modification of the surface or antibacterial coating

Introduction. Severe acetabular bone stock loss compromises the outcome in primary and revision total hip arthroplasty. This acetabular deficienca occurs very often in Rheumatoid Arthritis. In 1979 a biologic method was introduced with tightly impacted cancellous allograft in combination with a cemented polyethylene cup for acetabular reconstruction. With this technique it is possible to replace the loss of bone and restore hip function with a standard implant. Because of the poor long term results and our own experience with large solid grafts we started in 1998 to use the impaction grafting in primary and revision hip replacements in Osteoarthritis and Rheumatoid Arthritis. Materials and Methods. Between 1998 and 2001 35 acetabular reconstructions were performed in 29 patients with rheumatoid arthritis. 3 Patients were lost to follow up. 24 primary and 11 Revision Arthroplasties were performed. The average age was 55( 22-73. 29 female, 6 male. 58 Patients had additional dysplasia. We had cavitary, segmental and also combined defects. Femoral head autografts were used in all primaries, allografts were used in revision surgery. Firstly the peripheral and central segmental defects were close with a metal mesh, so that only a cavitary defect remained. The cavity was filled with bone chips which were impacred layer by layer. To strabilize these reconstruction cement was used in direct contact with the graft. In the Merle d’ Aubigne Score an improvement in pain, walking ability and function were observed. We had 1case of aseptic loosening, in a 73 year old female. After 10 month the grafts were incorporated. Our results are short term results- compared to the international literature ( Rosenberg et al. ) Nevertheless we can confirm the technique can be used with good results in cases with severe acetabular defects due to rheumatoid arthritis

Though over ten-year follow-up results of impaction bone grafting for acetabular reconstruction from European countries are available in literatures, clinical reports from Asian countries are rare. The purpose of the present study is to assess mid-term clinical and radiographic follow-up results at least three years after acetabular reconstruction with impaction bone grafting technique by single surgeon in Japanese cohort. The senior author performed 24 acetabular revisions with impaction bone grafting technique in 24 patients from February 2001 to June 2005. The average age of the patients at the revision was 67.5 years (36–82 years). The average follow-up period was 5 years and 5 months (3–7.3 years). The reasons for the operation were aseptic loosening of sockets in 17 hips and migration of bipolar heads in seven. The acetabular bone defects were classified as cavitary in 3 hips and as combined segmental-cavitary in 21 hips according to AAOS classification. For clinical assessment, Merle d’Aubigné and Postel hip score was assessed. Peri-operative complications were recorded. For radiological assessment, antero-posterior hip radiograph was analyzed pre-operatively, and post-operatively at one month, 6 months and every 6 months thereafter. Clear lines more than 2 mm around the sockets using DeLee and Charnley zone classification, and migration of the sockets were assessed. Hodgikinson’s type 3 (complete demarcation line) and type 4 (migration more than 5 mm or change of the angle more than 5 degrees) were classified as “loosening”. Kaplan-Meier survival analysis was performed with radiographic loosening and any re-operation (including recommendation for the re-operation) for the sockets as the end point, respectively. The mean Merle d’Aubigné and Postel hip score improved from 11.5 points before operation to 15.7 points at the final follow-up. Though, intra-operative blow-out fracture of the acetabular floor was detected in 3 hips, re-containment had been achieved by adding metal mesh or bone graft. Clear lines at cement-bone interface were detected at zone 3 in 2 hips. Migration more than 5 mm was detected in 2 hips of type III defect at 2 years and 6 months. Re-revision was recommended for one migrated hip at 3 years and 6 months after the operation, and the other hip was stable with no clinical symptom without progressive migration at the final follow-up of 5 years. The Kaplan-Meier survival analysis, with loosening and re-operation as the end point, predicted a rate of survival of the socket of 91.7% and 95.2% at 5 years, respectively. In conclusion, acetabular reconstruction with impaction bone grafting is attractive, but technical demanding procedure. The survival rate of the present series was compatible with the results of previous literatures. However, careful follow-up is essential, especially for the cases with massive bone defect

Femoral revision in cemented THA might include some technical difficulties, based on the loss of bone stock and cement removal, which might lead to further loss of bone stock, inadequate fixation, cortical perforation or consequent fractures. Femoral impaction grafting, in combination with a primary cemented stem, allows for femoral bone restoration by incorporating and remodeling the allograft bone of the host skeleton. Historically, this was first performed and described in Exeter in 1987. Indications might include all femoral revisions with bone stock loss, while the Endo-Clinic experience is mainly based on revision of cemented stems. Nowadays our main indication is the Paprosky Type IIIb and Type IV. Contraindications are mainly: septical revisions, extensive circumferential cortical bone loss and noncompliance of the patient. Generally the technique creates a new endosteal surface to host the cemented stem by reconstruction of the cavitary defects with impacted morselised bone graft. This achieves primary stability and restoration of the bone stock. It has been shown, that fresh frozen allograft shows superior mechanical stability than freeze-dried allografts. Technical steps include: . –. removal of failed stem and all cement rests. –. reconstruction of segmental bone defects with metal mesh (containment). –. preparation of fresh frozen femoral head allografts with bone mill. –. optimal bone chip diameter 2 to 5 mm, larger chips for the calcar area (6–8 mm). –. insertion of an intramedullary plug including central wire, 2 cm distal the stem tip. –. introduction of bone chips from proximal to distal. –. impaction started by distal impactors over central wire, then progressive larger impactors proximal. –. insertion of a stem „dummy“ as proximal impactor and space filler. –. removal of central wire. –. retrograde insertion of bone cement (0.5 Gentamycin) with small nozzle syringe, including pressurisation. –. insertion of standard cemented stem. The cement mantle is of importance as it acts as the distributor of force between the stem and bone graft while sealing the stem. A cement mantle of at least 2 mm has shown favourable results. Post-operative care includes usually touch down weight bearing for 6–8 weeks, followed by 4–6 weeks of gradually increased weightbearing with a total of 12 weeks on crutches. Relevant complications include mainly femoral fractures due to the hardly impacted allograft bone. Subsidence of tapered polished implants might be related to coldflow within the cement mantle, however, it could also be related to micro cement mantle fractures, leading to early failure. Subsidence should be less than 5 mm. Survivorship with a defined endpoint as any femoral revision after 10-year follow-up has been reported by the Exeter group at over 90%. While survivorship for revision defined as aseptic loosening is even greater at above 98%. Within the last years various other authors and institutions reported similar excellent survivorships, above 90%. In addition a long-term follow-up by the Swedish arthroplasty registry in more than 1180 patients reported a cumulative survival rate of 94% after 15 years and 99% with the endpoint aseptic loosening. Impaction grafting is technically more challenging and more time consuming than cement free distal fixation techniques. However, it enables a reliable restoration of bone stock

Bone impaction grafting (BIG) is a surgical technique for the restoration of bone stock loss with impaction of autograft or allograft bone particles (BoP). The goal of a series in-vitro and in-vivo experiments was to assess the suitability of deformable pure Ti (titanium) particles (TiP, FONDEL MEDICAL BV, Rotterdam, The Netherlands) for application as a full bone graft substitute in cemented revision total hip arthroplasty. TiP are highly porous (interconnective porosity before impaction 85 to 90%). In-vitro acetabular reconstructions were made in Sawbones (SAWBONES EUROPE, Malmö, Sweden) to evaluate migration by roentgen stereo photogrammetric analysis and shear force resistance by a lever out experiment. In-vitro femoral TiP reconstructions (SAWBONES, Malmö, Sweden) were used to evaluate micro-particle release and subsidence. Mature Dutch milk goats were used for two in-vivo experiments. A non-loaded femoral defect model was used to compare osteoconduction of bioceramic coated TiP with BoP and ceramic particles (CeP). Acetabular defects (AAOS type 3) were reconstructed in 10 goats using a metal mesh with impacted TiP acting as a full bone graft substitute in combination with a cemented polyethylene cup and a downsized cemented Exeter femoral stem (STRYKER BENOIST, Girard, France). Blood samples were taken for toxicological analysis. In-vitro: TiP were as deformable as BoP and created an entangled graft layer (porosity after impaction 70 to 75%). Acetabular TiP reconstructions were more stable and resistant to subsidence and shear force than BoP reconstructions (lever-out moment 56 ± 12 Nm respectively 12 ± 4 Nm, p < 0.001). After initial setting, femoral subsidence rates were smaller than seen in femoral bone impaction grafting (0.45 ± 0.04 mm after 300 000 loading cycles). Impaction generated 1.3 mg particles/g TiP (particle Ø 0.7–2 000 μm, tri-modal size distribution). In-vivo: Bioceramic coated (10 −40 μm) TiP showed bone ingrowth rates comparable to BoP and CeP. Reconstructed acetabular defects showed rapid bone ingrowth into the layer of TiP. Serum titanium concentrations slowly increased from 0.60 ± 0.28 parts per billion (ppb) preoperatively to 1.06 ± 0.70 ppb at fifteen weeks postoperatively (p = 0.04). Mechanical studies showed very good initial mechanical properties of TiP reconstructed defects. The in-vitro study showed micro-particle generation, but in the short-term goat studies, histology showed very few particles and no negative biological effects were found. The in-vivo acetabular study showed very favorable bone ingrowth characteristics into the TiP layer and a much thinner interface with the cement layer compared to similar defects reconstructed with BoP or mixtures of BoP with CeP. Further analysis in a human pilot study should proof that TiP is an attractive and safe alternative for allograft bone in impaction grafting revision arthroplasty