Aims. The mean age of patients undergoing total knee arthroplasty (TKA) has reduced with time. Younger patients have increased expectations following TKA. Aseptic loosening of the tibial component is the most common cause of failure of TKA in the UK. Interest in cementless TKA has re-emerged due to its encouraging results in the younger patient population. We review a large series of tantalum trabecular metal cementless implants in patients who are at the highest risk of revision surgery. Methods. A total of 454 consecutive patients who underwent cementless TKA between August 2004 and December 2021 were reviewed. The mean follow-up was ten years. Plain radiographs were analyzed for radiolucent lines. Patients who underwent revision TKA were recorded, and the cause for revision was determined. Data from the National Joint Registry for England, Wales, Northern Island, the Isle of Man and the States of Guernsey (NJR) were compared with our series. Results. No patients in our series had evidence of radiolucent lines on their latest radiological assessment. Only eight patients out of 454 required revision arthroplasty, and none of these revisions were indicated for aseptic loosening of the tibial baseplate. When compared to data from the NJR annual report, Kaplan-Meier estimates from our series (2.94 (95% confidence interval (CI) 1.24 to 5.87)) show a significant reduction in cumulative estimates of revision compared to all cemented (4.82 (95% CI 4.69 to 4.96)) or cementless TKA (5.65 (95% CI 5.23 to 6.10)). Our data (2.94 (95% CI 1.24 to 5.87)) also show lower cumulative revision rates compared to the most popular implant (PFC Sigma Cemented Knee implant fixation, 4.03 (95% CI 3.75 to 4.33)). The prosthesis time revision rate (PTIR) estimates for our series (2.07 (95% CI 0.95 to 3.83)) were lower than those of cemented cases (4.53 (95% CI 4.49 to 4.57)) from NJR. Conclusion. The NexGen trabecular (tantalum) cementless implant has lower revision rates in our series compared to all cemented implants and other types of cementless implants, and its use in younger patients should be encouraged. Cite this article: Bone Jt Open 2024;5(4):277–285

Objectives. We sought to determine if a durable bilayer implant composed of trabecular metal with autologous periosteum on top would be suitable to reconstitute large osteochondral defects. This design would allow for secure implant fixation, subsequent integration and remodeling. Materials and Methods. Adult sheep were randomly assigned to one of three groups (n = 8/group): 1. trabecular metal/periosteal graft (TMPG), 2. trabecular metal (TM), 3. empty defect (ED). Cartilage and bone healing were assessed macroscopically, biochemically (type II collagen, sulfated glycosaminoglycan (sGAG) and double-stranded DNA (dsDNA) content) and histologically. Results. At 16 weeks post-operatively, histological scores amongst treatment groups were not statistically different (TMPG: overall 12.7, cartilage 8.6, bone 4.1; TM: overall 14.2, cartilage 9.5, bone 4.9; ED: overall 13.6, cartilage 9.1, bone 4.5). Metal scaffolds were incorporated into the surrounding bone, both in TM and TMPG. The sGAG yield was lower in the neo-cartilage regions compared with the articular cartilage (AC) controls (TMPG 20.8/AC 39.5, TM 25.6/AC 33.3, ED 32.2/AC 40.2 µg sGAG/1 mg respectively), with statistical significance being achieved for the TMPG group (p < 0.05). Hypercellularity of the neo-cartilage was found in TM and ED, as the dsDNA content was significantly higher (p < 0.05) compared with contralateral AC controls (TM 126.7/AC 71.1, ED 99.3/AC 62.8 ng dsDNA/1 mg). The highest type II collagen content was found in neo-cartilage after TM compared with TMPG and ED (TM 60%/TMPG 40%/ED 39%). Inter-treatment differences were not significant. Conclusions. TM is a highly suitable material for the reconstitution of osseous defects. TM enables excellent bony ingrowth and fast integration. However, combined with autologous periosteum, such a biocomposite failed to promote satisfactory neo-cartilage formation. Cite this article: E. H. Mrosek, H-W. Chung, J. S. Fitzsimmons, S. W. O’Driscoll, G. G. Reinholz, J. C. Schagemann. Porous tantalum biocomposites for osteochondral defect repair: A follow-up study in a sheep model. Bone Joint J 2016;5:403–411. DOI: 10.1302/2046-3758.59.BJR-2016-0070.R1

Abstract. Background. Although tantalum is a well recognised implant material used for revision arthroplasty, little is known regarding the use of the same in primary total hip arthroplasty. Methods. A literature search was performed to find all relevant clinical studies until March 2020, which then underwent a further selection criteria. The inclusion criteria was set as follows: Reporting on human patients undergoing primary total hip arthroplasty; Direct comparison between tantalum acetabular cups with conventional acetabular cups. for use in primary total hip arthroplasty; Radiological evaluation (cup migration, osteointegration); Clinical (functional scores, need for subsequent revision, patient-reported outcomes; Post-operative complications; Reporting findings in the English Language. After a thorough search a total of six studies were included in the review. The primary outcome. measures were clinical outcomes, implant migration, change in bone mineral density and rate of revision and infection. Results. Tantalum was found superior to titanium with regards to fewer radiolucencies, survivorship, osteointegration, decreased osteolysis and mechanical loosening. No significant difference in radioisometric analysis, bone mineral density or Harris Hip Score was found. Revision and infection rates were found to be significantly lower in tantalum group at 10 years from pooled data of national joint registry. Conclusion. The use of tantalum can be reserved for cases of high risk of failure or mechanical loosening, where failure of a contralateral joint occurred as it carries lower risk of failure and infection. Further studies with longer follow-up would be useful in drawing further conclusions

First-time revision acetabular components have a 36% re-revision rate at 10 years in Australia, with subsequent revisions known to have even worse results. Acetabular component migration >1mm at two years following revision THA is a surrogate for long term loosening. This study aimed to measure the migration of porous tantalum components used at revision surgery and investigate the effect of achieving press-fit and/or three-point fixation within acetabular bone. Between May 2011 and March 2018, 55 patients (56 hips; 30 female, 25 male) underwent acetabular revision THR with a porous tantalum component, with a post-operative CT scan to assess implant to host bone contact achieved and Radiostereometric Analysis (RSA) examinations on day 2, 3 months, 1 and 2 years. A porous tantalum component was used because the defects treated (Paprosky IIa:IIb:IIc:IIIa:IIIb; 2:6:8:22:18; 13 with pelvic discontinuity) were either deemed too large or in a position preventing screw fixation of an implant with low coefficient of friction. Press-fit and three-point fixation of the implant was assessed intra-operatively and on postoperative imaging. Three-point acetabular fixation was achieved in 51 hips (92%), 34 (62%) of which were press-fit. The mean implant to host bone contact achieved was 36% (range 9-71%). The majority (52/56, 93%) of components demonstrated acceptable early stability. Four components migrated >1mm proximally at two years (1.1, 3.2, 3.6 and 16.4mm). Three of these were in hips with Paprosky IIIB defects, including 2 with pelvic discontinuity. Neither press-fit nor three-point fixation was achieved for these three components and the cup to host bone contact achieved was low (30, 32 and 59%). The majority of porous tantalum components had acceptable stability at two years following revision surgery despite treating large acetabular defects and poor bone quality. Components without press-fit or three-point fixation were associated with unacceptable amounts of early migration

First-time revision acetabular components have a 36% re-revision rate at 10 years in Australia, with subsequent revisions known to have even worse results. Acetabular component migration >1mm at two years following revision THA is a surrogate for long term loosening. This study aimed to measure the migration of porous tantalum components used at revision surgery and investigate the effect of achieving press-fit and/or three-point fixation within acetabular bone. Between May 2011 and March 2018, 55 patients (56 hips; 30 female, 25 male) underwent acetabular revision THR with a porous tantalum component, with a post-operative CT scan to assess implant to host bone contact achieved and Radiostereometric Analysis (RSA) examinations on day 2, 3 months, 1 and 2 years. A porous tantalum component was used because the defects treated (Paprosky IIa:IIb:IIc:IIIa:IIIb; 2:6:8:22:18; 13 with pelvic discontinuity) were either deemed too large or in a position preventing screw fixation of an implant with low coefficient of friction. Press-fit and three-point fixation of the implant was assessed intra-operatively and on postoperative imaging. Three-point acetabular fixation was achieved in 51 hips (92%), 34 (62%) of which were press-fit. The mean implant to host bone contact achieved was 36% (range 9–71%). The majority (52/56, 93%) of components demonstrated acceptable early stability. Four components migrated >1mm proximally at two years (1.1, 3.2, 3.6 and 16.4mm). Three of these were in hips with Paprosky IIIB defects, including 2 with pelvic discontinuity. Neither press-fit nor three-point fixation was achieved for these three components and the cup to host bone contact achieved was low (30, 32 and 59%). The majority of porous tantalum components had acceptable stability at two years following revision surgery despite treating large acetabular defects and poor bone quality. Components without press-fit or three-point fixation were associated with unacceptable amounts of early migration

Introduction. Periprosthetic joint infection (PJI) remains the main cause of failure in primary and revision total knee arthroplasties (TKAs). Local delivery of antibiotics, mainly antibiotic-loaded bone cement (ALBC), is commonly employed to prevent PJI. Over the past decade, tantalum and porous titanium have been successfully utilized as metaphyseal fixation devices to address bone loss and improve biologic fixation during revision TKA. However, no study has examined the antimicrobial properties compared to bone cement. The purpose of this study was to compare the ability of tantalum, 3D porous titanium, antibiotic-loaded bone cement (ALBC) and smooth titanium alloy (STA) to inhibit Staphylococci bacterial agents in an in vitro medium environment, based on the evaluation of the zone of inhibition (ZOI) and the antibacterial activity duration. Our study hypothesis was that we will found no significant difference between groups to inhibit Methicillin-Sensitive or Methicillin-Resistant Staphylococcus aureus (MSSA/MRSA) agents. Methods. Thirty beads made of 3 different materials (tantalum/ 3D porous titanium/ STA) were bathed during 1hour inside of a solution made of 1g vancomycin with 20-mL of sterile water for injection (bath concentration: 50 mg/mL). Ten 1cm. 3. cylinders were also created mixing standard surgical cement with 1g of Vancomycin in standardized sterile molds (ALBC beads). Finally, thirty beads made of tantalum/ 3D porous titanium/ STA were bathed in phosphate buffered saline solution to act as a control group. Cylinders were then placed on agar plates inoculated with MSSA and MRSA. Inhibition zone diameters were measured each day and cylinders were transferred onto a new inoculated plate. Inhibition zones were measured with a manual Vernier caliper and with automated software. The mean inhibition zones between groups were compared using the Wilcoxon Test. Results. The inter-class coefficient correlation values indicated an optimal intra-observer and inter-observer reproducibility for ZOI measurement (ICC 0.96 and ICC 0.98). For MSSA and MRSA, no inhibitory effect was found in the control group and antibiotic-loaded STA beads exhibited a short inhibitory effect until day 2. For MSSA, both tantalum and 3D porous titanium beads exhibited larger inhibition zones than cement beads (all p<0.01) each day until day 7 for tantalum and until day 3 for 3D porous titanium. After 6 days, ALBC presented larger inhibition zone than the 3D porous titanium, but no difference was found with tantalum. For MRSA, both tantalum and 3D porous titanium beads had significantly larger inhibition zones than ALBC each day until day 6 for tantalum (all p<0.01) and until day 3 for 3D porous titanium (all p<0.04). ALBC presented larger inhibition zone than tantalum and 3D porous titanium from day 7 to 9 (all p<0.04). Conclusion. Our results demonstrate that porous metal implants can deliver local antibiotics over slightly varying time frames based on our in vitro analysis. Antibiotic-impregnated tantalum and 3D porous titanium constructs exhibited superior antimicrobial properties when compared to STA. Future goals include impregnating porous metals with antibiotics for intraoperative use during revision TKA. For figures, tables, or references, please contact authors directly

Glenoid failure remains the most common mode of total shoulder arthroplasty failures. Porous tantalum metal (Trabecular Metal™, Zimmer) have grown in popularity in hip and knee arthroplasty. First-generation porous tantalum metal-backed glenoid components demonstrated metal debris, resulted in failure, and were revised to second-generation glenoid implants. Evidence for second-generation porous tantalum metal implants in shoulder arthroplasty is sparse.1–4 The purpose of this study was to assess clinical and radiographic outcomes in a series of patients with second-generation porous tantalum glenoid components at a minimum two-years postoperative. We retrospectively reviewed the clinical and radiographic outcomes of patients who received a second-generation porous tantalum glenoid component anatomic shoulder arthroplasty between May 2009 and December 2017 with minimum 24 months follow-up. The shoulder arthroplasties were performed by one of two senior fellowship-trained surgeons. We collected postoperative clinical outcome indicators: EQ5D visual analog scale (VAS), Western Ontario Osteoarthritis of the Shoulder (WOOS) Index, American Shoulder and Elbow Surgeons (ASES) Score, and Constant Score (CS). Radiographic review was performed by an independent fellowship-trained surgeon. The Endrizzi metal debris grading system1 was utilized to grade metal debris. We computed descriptive statistics and compared outcome scores between groups via the non-parametric Wilcoxon rank-sum test, with group-wise comparisons defined by: metal debris and humeral head migration (secondary analyses). Thirty-five patients [23 male (65.7%) and 12 female (34.3%)] with 40 shoulder replacements participated in the study. Forty of 61 shoulders (65.6%) had an average of 64 ± 20.3 months follow-up (range 31 to 95). Average BMI was 27.5 ± 4.4 kg/m2 (range 19.5 to 39.1). The average postoperative EQ5D VAS at final follow-up was 74.6 ± 22.5, WOOS Index 87.9 ± 16.6, ASES Score 88.3 ± 10.9, and CS 80.4 ± 13. At final follow-up, 18 of 40 shoulders (45%) had metal debris [15 of 40 (37.5%) Endrizzi grade 1 and three of 40 (7.5%) Endrizzi grade 2], and 22 of 40 shoulders (55%) did not show evidence of metal debris. There was one non-revision reoperation (open subscapularis exploration), one shoulder with anterosuperior escape, three shoulders with glenoid radiolucencies indicative of possible glenoid loosening, and nine shoulders with superior migration of the humeral head (>2mm migration at final follow-up compared to immediate postoperative). When comparing postoperative scores between patients with vs without metal debris, we found no statistically significant difference in the EQ5D VAS, WOOS Index, ASES Score and CS. On further analyses, when comparing superior migration of the humeral head and postoperative outcomes scores, we found no statistically significant difference. We report the longest published follow-up with clinical and radiographic outcomes of second-generation porous tantalum glenoid anatomic shoulder arthroplasties. In this series of patients, 45% of total shoulder arthroplasties with a second-generation porous tantalum glenoid implant had radiographic evidence of metal debris. This metal debris was not statistically associated with poorer postoperative outcomes. Further investigation and ongoing follow-up are warranted

Introduction. Tantalum trabecular metal components are increasingly used to reconstruct major bone defects in revision arthroplasty surgery. It is known that some metals such as silver have antibacterial properties. Recent reports have raised the question as to whether Tantalum components are protective against infection in revision surgery. This is based on a retrospective, single institution review, of revision cases comparing tantalum with titanium acetabular implants, which reported a lower incidence of subsequent infection in the tantalum group. This laboratory study aimed to establish if tantalum had any intrinsic antibacterial properties against planktonic bacteria or ability to inhibit biofilm formation. Materials and methods. Equal sized pieces of tantalum (Trabecular metal, Zimmer UK) and titanium (Trilogy, Zimmer UK) were sterilised and then incubated with a low dose inoculum of either Staphylococcus aureus or Staphylococcus epidermidis for 24 hours. After serial dilution, colony forming units were quantified on MH agar plates. To establish the ability to inhibit biofilm formation these tantalum and titanium pieces were then washed twice, sonicated and washed again to remove loosely adhered planktonic bacteria. They were then re-incubated for 24 hours prior to quantifying colony forming units. All experiments were performed in triplicate. Results. More than 1×10. 8. cfu/ml were observed in both the titanium and tantalum experiments. After washing and sonication more than 2×10. 7. cfu/ml were observed for both tantalum and titanium groups. The results were the same for both Staph Aureus and Staph Epidermidis. Discussion. Compared with titanium controls tantalum did not demonstrate any intrinsic antibacterial activity or ability to inhibit biofilm formation. The intrinsic properties of tantalum do not account for the previously observed reduction in subsequent infection when tantalum was used in the revision procedure. Conclusion. Tantalum does not have any intrinsic antimicrobial properties or ability to inhibit biofilm formation

Introduction. Tantalum is a pure metallic element and is attractive for use in orthopaedic implants because it is one of the most biocompatible metals available for implant fabrication. The potential advantages for the use of porous tantalum in total hip arthroplasty include: 1) excellent bone and tissue ingrowth observed histologically; 2) direct polyethylene intrusion into the metal substrate. This allows the elimination of any potential backside wear in the monoblock cup; 3) The two-piece design consist of a tantalum shell with screw holes for fixation into the dome of the ilium and posterior column. A polyethylene liner is cemented into the tantalum shell to eliminates backside motion. In addition, acetabular augments of porous tantalum have been developed for use in restoration of major bone deficiencies. Prospective study on a case serie of 113 THA’s performed by two surgeons in a single institution. Material & Methods. From 2000 to December 2003, 113 hips have undergone arthroplasty using porous tantalum implants consisting of 54 primary hip arthroplasties and 59 revision THA’s. The patients where evaluated clinical and radiographically every 3 month during the first year, and after yearly. Mean patient age was 64,2 years, (range 44–87); with 59% males and 41% females. Results. No patients died or lost to follow-up. No further surgeries of the involved hip. No radiographic signs of loosening of the acetabular component according to the criteria of Hodgkinson et al. No problems specifically from the use of acetabular augments or extra screws has been noted. Of the revision series, a total of 16 cases have received acetabular augments. Complications included 1 superficial infection, 2 dislocations. No vasculo-nervous complication; and in 2 cases technical difficulties to achieve good fixation due to ethiology of the THA (desarthrodesis). The average Harris hip score improved from 48 to 89 following primary surgery. Discussion and Conclusions Tantalum acetabular components for primary and revision hip surgery have performed well for up to 3 years, and have excellent stability. The two-piece acetabular shell and augments permits the reconstruction of every acetabular bone defect

Femoral head osteonecrosis is a progressive disease that affects patients in the third to the fifth decades. It is probably a multifactorial disease since many patients that have the known risk factors never develop it and others develop the disease without any risk factors. There isn’t any totally effective treatment that can stop the disease and prevents bone collapse, but it is known that operative treatment gives better results than conservative treatment in Ficat stages I and II. The authors began in October of 2003 the surgical treatment of pre-collapse patients (Ficat stage I and II) with the tantalum hip screw hopping that it could prevent progression to collapse. The tantalum is an innovating new metal with an excellent bio-integration and with mechanic properties very close to normal bone. The tantalum hip screw gives structural support to the necrotic bone segment, permits immediate charging of the affected hip and pretends to be a substitute to peroneal graft. There isn’t any published clinical result of the use of the tantalum hip screw in the literature to date. Between the October of 2003 and November of 2004 we made 10 such procedures in 8 patients with mean age of 44 years. The patients were Ficat grade I and II and we could identify that most of the patients had been taking corticosteroid medication. There was one hip with less than 15% of extension and 9 with a severe extension (more than 30% of the femoral head from the University of Pennsylvania system of classification and staging). There was rapid radiographic progression of the disease in all patients but one with bilateral involvement. There was progression for femoral head collapse in 70% of the patients despite the femoral hip screw. In 3 patients the collapse led to screw protrusion on the acetabulum and needed hip arthroplasty, on average, 12 months after screw implantation. The harris hip score of the 5 patients (7 hips) than weren’t submitted to hip arthroplasty gave a good result in 1 patient and a fair result in 3 patients (4 hips). There was a poor result in the other patient. The tantalum hip screw made it more difficult to do a hip arthroplasty but it didn’t make it impossible. This study shows that the tantalum hip screw didn’t prevent the progression of the femoral neck osteonecrosis in all but one patient with an initial Ficat grade IIa. The fact that 9 in 10 patients had a severe extension of the disease (> 30% of the femoral head diameter) could have prevented the success of the tantalum hip screw because the area of sustention of the screw was limited and the disease continued to progress around the screw

The osteo-regenerative properties of allograft have recently been enhanced by addition of autogenous skeletal stem cells to treat orthopaedic conditions characterised by lost bone stock. There are however, multiple disadvantages to allograft, including cost, availability, consistency and potential for disease transmission, and trabecular tantalum represents a potential alternative. Tantalum is already in widespread orthopaedic use, although in applications where there is poor initial implant stability, or when tantalum is used in conjunction with bone grafting, loading may need to be limited until sound integration has occurred. Development of enhanced bone-implant integration strategies will improve patient outcomes, extending the clinical applications of tantalum as a substitute for allograft. The aim of this study was to examine the osteoconductive potential of trabecular tantalum in comparison to human allograft to determine its potential as an alternative to allograft. Human bone marrow stromal cells (500,000 cells per ml) were cultured on blocks of trabecular tantalum or allograft for 28 days in basal and osteogenic media. Molecular profiling, confocal and scanning electron microscopy, as well as live-dead staining and biochemical assays were used to characterise cell adherence, proliferation and phenotype. Cells displayed extensive adherence and proliferation throughout trabecular tantalum evidenced by CellTracker immunocytochemistry and SEM. Tantalum-cell constructs cultured in osteogenic conditions displayed extensive matrix production. Electron microscopy confirmed significant cellular growth through the tantalum to a depth of 5mm. In contrast to cells cultured with allograft in both basal and osteogenic conditions, cell proliferation assays showed significantly higher activity with tantalum than with allograft (P<0.01). Alkaline phosphatase (ALP) assay and molecular profiling confirmed no significant difference in expression of ALP, Runx-2, Col-1 and Sox-9 between cells cultured on tantalum and allograft. These studies demonstrate the ability of trabecular tantalum to support skeletal cell growth and osteogenic differentiation comparable to allograft. Trabecular tantalum represents a good alternative to allograft for tissue engineering osteo-regenerative strategies in the context of lost bone stock. Such clinical scenarios will become increasingly common given the ageing demographic, the projected rates of revision arthroplasty requiring bone stock replacement and the limitations of allograft. Further mechanical testing and in vivo studies are on-going

Introduction. Achieving durable implant–host bone fixation is the major challenge in uncemented revision hip arthroplasty when significant bone stock deficiencies are encountered. The purpose of this study was to develop an experimental model which would simulate the clinical revision hip scenario and to determine the effects of alendronate coating on porous tantalum on gap filling and bone ingrowth in the experimental model. Methods. Thirty-six porous tantalum plugs were implanted into the distal femur, bilaterally of 18 rabbits for four weeks. There were 3 groups of plugs inserted; control groups of porous tantalum plugs (Ta) with no coating, a 2nd control group of porous tantalum plugs with micro-porous calcium phosphate coating, (Ta-CaP) and porous tantalum plugs coated with alendronate (Ta-CaP-ALN). Subcutaneous fluorochrome labelling was used to track new bone formation. Bone formation was analysed by backscattered electron microscopy and fluorescence microscopy on undecalcified histological sections. Results. The relative increase in mean volume of gap filling, bone ingrowth and total bone formation was 124%, 232% and 170% respectively in Ta-CaP-ALN compared with the uncoated porous tantalum (Ta) controls, which was statistically significant. The contact length of new bone formation on porous tantalum implants in Ta-CaP-ALN was increased by 700% (8-fold) on average compared with the uncoated porous tantalum (Ta) controls. Discussion. Alendronate coated porous tantalum significantly modulated implant bioactivity compared with controls. This study has demonstrated the significant enhancement of bone-implant gap filling and bone ingrowth, which can be achieved by coating porous tantalum with alendronate. It is proposed that, when faced with the clinical problem of revision joint replacement in the face of bone loss, the addition of alendronate as a surface coating would enhance biological fixation of the implant and promote the healing of bone defects

Highly porous tantalum cups have been used in complex acetabular revisions for nearly 20 years but reports of long term results are limited. This study was designed to report ten year results of revision using a single porous tantalum cup design with special attention to re-operation for any reason, all-cause revision, and revision for aseptic loosening. Retrospective review of all revision THA cases performed from 1999–2006 using a highly porous tantalum acetabular component design with multiple screw holes and a cemented polyethylene liner (Zimmer Biomet, Warsaw, IN). Our institutional medical record and total joint registry were used to assess follow-up and xrays were reviewed. The Paprosky classification system was used to rate acetabular bone loss. Radiographic loosening was defined as new/progressive radiolucencies in all 3 acetabular zones, or cup migration (>2mm). Kaplan-Meier survivorship was used to assess survivorship free of cup revision/removal for any reason, and free of revision for aseptic loosening. Between 1999 and 2006 this tantalum cup was used in 916 revisions. Mean age: 66 (±6), BMI: 29 (±6), and male: 42%. Indications for revision: aseptic loosening 346 (38%), osteolysis 240 (26%), and infected arthroplasty 168 (18%). Large (3A or 3B) bone defects were present in 260, and pelvic discontinuity in 61. Reoperation for any reason: 133 (15%), but 84 of 133 cases did not require cup revision for instability (38) or femoral failure (24). Tantalum cup removal/revision was required in 49 (5.3%) for deep infection (39) and recurrent dislocation (6), and aseptic loosening (4). 10 year survivorship free of cup revision for any reason: 95% and for aseptic loosening: 99%. Radiographic review (mean 10 years): suspicious for aseptic loosening in another 4 cups. A highly porous tantalum acetabular component with multiple screws and a cemented polyethylene insert provided durable long term fixation for an array of acetabular revision problems. Long term aseptic loosening was very rare (<1%) and cup removal was mainly related to deep infection, and rarely dislocation

Introduction: Non union of the humerus in the ostoeportic bone is a great challenge for the orthopedic surgeon. The non weight bearing nature of this bone together with extreme osteoporosis seen in the elderly had rendered a high degree of failure in different modes of internal fixation of established humeral non union. Tantalum is a trabecullar metal with biomechanical properties similar to bone with a high modulus of elasticity and low rigidity. It is proved both in vitro and in vivo to induce excellent bone and vascular in growth and have been used successfully treating other application in orthopedics. We have introduced the tantalum rod for the treatment of humeral non union in the elderly. Patients and Methods: Six patients with humeral non-union were selected for tantalum rod implantations. All were above 60 years old. All patients had established non and 4 had failures after previous osteosynthesis. The surgical technique was exploration of the fracture site via a posterior or an anterolateral approach, debridement of the fracture site and intramedullary insertion of a 100 mm x 10 mm tantalum rod. No bone grafting was used. Ancillary fixation included a 4.5 broad DCP plate with screws drilled into both bone and rod or screws alone drilled into the bone and tantalum construct. Follow up period was up to one year. Results: All fractures united clinically and radiographicaly up to 3 months. All patients achieved satisfactory shoulder and elbow range of motion and regained functional activity. No infection or foreign body reaction was noted. Conclusion: Intramedullary tantalum rodding is a viable treatment option for the cases in both primary and secondary non union of the humeral shaft in osteoporotic bone

Pure tantalum has been proposed in orthopaedic surgery. Its chemical and physical properties have been widely studied in the past. From pure tantalum is obtained a spongy structure (Trabecular Metal Technology: TMT) that shows a full thickness porosity which is 2–3 times higher compared to other surfaces available for bone ingrowth with a three-dimensional porous arrangement in rough trabeculae. Pores (average diameter of 650 mm) are fully interconnected and represent 75–80% of the whole volume. TMT acetabular components have an elliptical shape and have an irregular external surface which both allow an optimal mechanical fit. We retrospectively reviewed 212 cases of monoblock porous tantalum acetabular cup (Hedrocel, Stratec) implanted between 1999 and 2003 in a single centre with a minimum follow-up of 9–10 years; There were 98 men and 114 women, with an average age of 65 years. They all underwent primary or revision total hip arthroplasty or to acetabular component revision alone. In all patients a monoblock porous tantalum acetabular component with polyethylene directly compression molded into cup, with or without peripheral holes for screws, was implanted. In all primary procedures the same femoral stem (Synergy, Smith and Nephew) was implanted. All patients were evaluated with a clinical examination (Harris Hip Score: HHS) and with standard radiographs of the pelvis preoperatively and 1, 3, 6 months and yearly postoperatively. The stability of the acetabular cup was determined by modified Engh's criteria. The HHS score improved from 42 preoperatively to 94 after one year; at 13 years follow-up it was 95. The subjective outcome was widely satisfying, with the majority of patients experimenting good functional recovery and return to daily activities. Osteointegration of the acetabular component was present in all X-rays controls at one year after surgery. All post-operative evidence of residual bone loss (geodes, bone defects in revisions and in displasia) were no more radiographically evident after 1 year postoperatively as the host bone quickly filled these gaps. We did not observe osteolysis nor progressive radiolucent lines at the latest follow-up. None of the cups was revised, except 3 cases, revised for infection. Both clinical and radiographic results are the same or even superior to those of coated implants. Our experience confirms that trabecular metal tantalum cups can avoid the formation of bone-implant interface membrane and consequently can avoid implant loosening. The most important advantages of TMT monoblock cups are: no potential for polyethylene backside wear, prevention of loosening and osteolysis, increased early fixation via friction, improved late biological stability, maximum bone-implant contact. High biocompatibility of porous tantalum and its elastic modulus very close to bone influence positively earlier and wider osteointegration of the implant. Larger series are needed to confirm the positive our preliminary results

Introduction:. One method of femoral head preservation following avascular necrosis (AVN) is core decompression and Tantalum Rod insertion. There is, however, a published failure rate of up to 32% at 4 years. The purpose of the present study was to document the clinical and radiological outcome following Total Hip Arthroplasty (THA) subsequent to failed Tantalum Rod insertion. Methods:. Twenty-five failed Tantalum Rod insertions subsequently requiring THA were identified from a prospectively updated database. Seventeen patients met minimum 2 year clinical and radiographic follow-up criteria. St. Michael's Hip (SMH) scores were compared to a matched cohort of patients with THA for AVN without prior Tantalum Rod insertion. Postoperative radiographs were reviewed assessing component alignment, linear wear (Dorr & Wan) and presence of tantalum residue within the joint space. Results:. Nine females and eight males underwent removal of a Tantalum Rod with subsequent THA between May 2005 and March 2010. The mean time between Tantalum Rod insertion and conversion to THA was 23 months (range 6–48) with a mean follow-up of 3.5 years (range 2–5). At each follow-up interval the mean SMH scores were comparable between the two groups (p = 0.445). Femoral stem alignment (p = 0.428) and acetabular cup inclination (p = 0.723) were comparable between groups. Articular tantalum residue was identified in 12 of 17 articulations (7 mild, 3 moderate, 2 severe). Linear wear rates were comparable between the tantalum group (0.07 mm/yr, range 0.01–0.40) and controls (0.07 mm/yr, range 0.02–0.21, p = 0.951). There was no evidence of catastrophic wear. Conclusion:. Tantalum rod conversion to THA in the young adult patient with AVN reveals no early catastrophic sequelae. In the short term, Tantalum Rod insertion does not demonstrate a deleterious effect on subsequent total joint replacement surgery. There is, however, a high rate of retained tantalum debris within the effective joint space with the procedure and thus there is an unknown risk of accelerated articular wear necessitating longer term study

Introduction: Achieving durable implant–host bone fixation is the major challenge in uncemented revision hip arthroplasty when significant bone stock deficiencies are encountered. The purpose of this study was. to develop an experimental model which would simulate the clinical revision hip scenario and. determine the effects of alendronate coating on porous tantalum on gap filling and bone ingrowth in the experimental model. Methods: Thirty-six porous tantalum plugs were implanted into the distal femur, bilaterally of 18 rabbits for four weeks. There were 3 groups of plugs inserted; control groups of porous tantalum plugs (Ta) with no coating, a 2nd control group of porous tantalum plugs with micro-porous calcium phosphate coating, (Ta-CaP) and porous tantalum plugs coated with alendronate (Ta-CaP-ALN). Subcutaneous fluorochrome labelling was used to track new bone formation. Bone formation was analysed by backscattered electron microscopy and fluorescence microscopy on undecalcified histological sections. Results: The relative increase in mean volume of gap filling, bone ingrowth and total bone formation was 124 %, 232 % and 170 % respectively in Ta-CaP-ALN compared with the uncoated porous tantalum (Ta) controls, which was statistically significant. The contact length of new bone formation on porous tantalum implants in Ta-CaP-ALN was increased by 700% (8-fold) on average compared with the uncoated porous tantalum (Ta) controls. Discussion: Alendronate coated porous tantalum significantly modulated implant bioactivity compared with controls. This study has demonstrated the significant enhancement of bone-implant gap filling and bone ingrowth, which can be achieved by coating porous tantalum with alendronate. It is proposed that, when faced with the clinical problem of revision joint replacement in the face of bone loss, the addition of alendronate as a surface coating would enhance biological fixation of the implant and promote the healing of bone defects

Introduction: Achieving durable implant–host bone fixation is the major challenge in uncemented revision hip arthroplasty when significant bone stock deficiencies are encountered. The purpose of this study was 1) to develop an experimental model which would simulate the clinical revision hip scenario and 2) determine the effects of alendronate coating on porous tantalum on gap filling and bone ingrowth in the experimental model. Methods: Thirty-six porous tantalum plugs were implanted into the distal femur, bilaterally of 18 rabbits for four weeks. There were 3 groups of plugs inserted; control groups of porous tantalum plugs (Ta) with no coating, a 2. nd. control group of porous tantalum plugs with micro-porous calcium phosphate coating, (Ta-CaP) and porous tantalum plugs coated with alendronate (Ta-CaP-ALN). Subcutaneous fluorochrome labelling was used to track new bone formation. Bone formation was analysed by backscattered electron microscopy and fluorescence microscopy on undecalcified histological sections. Results: The relative increase in mean volume of gap filling, bone ingrowth and total bone formation was 124 %, 232 % and 170 % respectively in Ta-CaP-ALN compared with the uncoated porous tantalum (Ta) controls, which was statistically significant. The contact length of new bone formation on porous tantalum implants in Ta-CaP-ALN was increased by 700% (8-fold) on average compared with the uncoated porous tantalum (Ta) controls. Discussion: Alendronate coated porous tantalum significantly modulated implant bioactivity compared with controls. This study has demonstrated the significant enhancement of bone-implant gap filling and bone ingrowth, which can be achieved by coating porous tantalum with alendronate. It is proposed that, when faced with the clinical problem of revision joint replacement in the face of bone loss, the addition of alendronate as a surface coating would enhance biological fixation of the implant and promote the healing of bone defects

The problem of early mechanical stability and late biological osseointegration of the tibial component is still a debated issue in total knee arthroplasty. We are among those authors that stress the necessity of cementing the tibial component to avoid the risk of failure due to the high torque stresses at this interface. In fact while on the femoral edge a good stability can be achieved even in uncemented implants, the stability of traditional tibial components is harder to obtain even in cemented implants. To solve this problem it has been proposed to use additional devices such as screws, pegs or keels to better fix the tibial plateau. Tantalum monobloc tibial tray is a new answer to this problem. It consists in a cement-less tibial tray made of porous tantalum with monobloc polyethylene. Chemical, physical and biological properties of the raw tantalum are very similar to those of titanium. Porosity of the processed material is 80% (2–3 times compared to plasma spray, beads and fiber mesh coatings) and pores, which diameter is 650 mm, are fully interconnected in the whole bulk of the implant. This trabecular spongy structure, that is not a coating, allows the bone at the interface to deeply grow into the pores, and to achieve optimal stability. In addiction, the fusion of polyethylene into the tantalum mesh completely abolish the back side wear problem. With this technology is yet in use an acetabular component, with which we have a 5 years experience in 150 implants, and now is available a new tibial plateau; the first implant in Europe was performed in our department. Despite our short series and follow up (6 implants in 2 months) the properties of porous tantalum, already tested in acetabular implants, represent an alternative to the traditional ways of tibial tray fixation

Recently, the osteoregenerative properties of allograft have been enhanced by addition of autogenous skeletal stem cells to treat orthopaedic conditions characterised by lost bone stock. There are multiple disadvantages to allograft, and trabecular tantalum represents a potential alternative. This metal is widely used, although in applications where there is poor initial stability, or when it is used in conjunction with bone grafting, loading may need to be limited until sound integration has occurred. Strategies to speed up implant incorporation to surrounding bone are therefore required. This may improve patient outcomes, extending the clinical applications of tantalum as a substitute for allograft. Aim. To use tissue engineering strategies to enhance the reconstructive properties of tantalum, as an alternative to allograft. Methods. Human bone marrow stromal cells (5×10. 5. cells/ml) were cultured on blocks of trabecular tantalum or allograft for 28 days in basal and osteogenic media. Molecular profiling, confocal and scanning electron microscopy, as well as live/dead staining and biochemical assays were used to detail cell adherence, proliferation and phenotype. Results. Cells displayed extensive adherence and proliferation throughout trabecular tantalum. Samples cultured in osteogenic conditions showed abundant matrix production. Electron microscopy confirmed significant cellular growth through tantalum to a depth of 5mm. In contrast to cells cultured with allograft in both basal and osteogenic conditions, cell proliferation and biochemical assays showed significantly higher activity with tantalum than allograft. Furthermore, alkaline phosphatase (ALP) assay and molecular profiling confirmed no significant difference in expression of ALP, Runx-2, Col-1 and Sox-9 between cells cultured on tantalum and allograft. Conclusions. These studies demonstrate trabecular tantalum supports cell growth and osteogenic differentiation at least as well as allograft. Trabecular tantalum represents a good alternative to allograft for tissue engineering osteoregenerative strategies in the context of lost bone stock. Further mechanical testing and in vivo studies are on-going