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

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. 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

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

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

Introduction. The optimal management of severe tibial and/or femoral bone loss in a revision total knee arthroplasty (TKA) has not been established. Reconstructive methods include structural or bulk allografts, impaction bone-grafting with or without mesh augmentation, custum prosthetic components, modular metal augmentations of prosthesis and tumor prosthesis. Recently metaphyseal fixation using porous tantalum cones (Zimmer, Warsaw, IN) has been proposed as alternative strategy for severe bone loss. Objectives. The purposes of this study were to determine the clinical and radiographic outcomes in patients who underwent revision knee arthroplasty with tantalum cones with a minimum of 5-year follow-up. Methods. From November 2005 to August 2008 a total of 26 porous tantalum metaphyseal cones were used to reconstruct severe tibial and/or femoral bone loss in 18 patients during revision TKA at a single institution. There were 12 females and 6 males with an average age of 73 years (range 55–84) at the time of revision. The mean clinical and radiographic follow-up was 6.3 years (range, 5–8). The reasons for revision were aseptic loosening (5 cases) and deep infection (13 cases). A Two stage procedure was used in all septic cases. According to the Anderson Orthopaedic Reseach Institute (AORI) bone defects classification all femoral and tibial defects were rated 2B and 3 (3 T2b, 9 T3, 3 F2b and 10 F3). A femoral cone was inserted in 6 patients, a tibial cone was inserted in 5, a double cone in 6 (femoral and tibial), and a triple cone in 1 (1 femoral and 2 tibial). A constrained condylar implant (LCCK, Zimmer, Warsaw) was inserted in 6 patients and a rotating hinge knee implants (RHK, Zimmer, Warsaw, IN) in 12 pateints. All patients were prospectively followed for clinical and radiographic evaluation preoperatively and postoperatively at 1, 3, 6 months, one year and yearly thereafter. Results. Knee Society knee scores improved from a mean of 31.3 points before surgery to 76.7 points at latest followup (p < 0.001). Knee Society function scores improved from a mean of 21.7 points before surgery to 65.4 points at latest followup (p < 0.001). The average flexion contracture was 6° and the average flection was 88°. At the time of the latest follow-up the average flexion contraction was 3° and the average flexion was 105°. No radiolucent lines were seen between the cones and the adjacent tibial and femoral bone at the latest follow-up. There was no evidence of loosening or migration of any implant at the time of the final follow-up. There have been two reoperations for recurrent infection (11%). Conclusions. Our experience demonstrates excellent clinical and radiographic mid-term outcomes and confirms that metaphyseal fixation with porous tantalum cones can be achieved. Long-term follow up and comparative studies are necessary

Purpose. Durable fixation may be difficult to achieve when significant bone loss is present, as it occurs in pelvic sarcoma resection and revision surgery of tumor implants. Purpose of this study was to review clinical results of primary and revision surgery of the pelvis and lower extremity in the setting of severe bone loss following limb salvage procedures for bone sarcoma using modular porous tantalum implants. Method. Retrospective study of 15 patients (nine females, six males) undergoing primary or revision pelvic reconstruction (five patients) or revision surgery of a tumor implant of the hip (five patients), knee (four patients), and ankle (one patient) using porous tantalum implants was undertaken. Reason for the tumor implant was resection of bone sarcoma in 13 cases and tumor-like massive bone loss in the remaining two cases. Cause for revision was aseptic failure (nine patients) or deep infection (six patients); average age at the time of surgery was 31 years (16–61 yrs). Revision was managed in a staged fashion in all the six infected cases. All patients presented severe combined segmental and cavitary bone defects. Bone loss was managed in all patients using porous tantalum implants as augmentation of residual bone stock and associated with a megaprosthesis in eight cases (five proximal femur, two distal femur, one proximal tibia). Average follow-up was 4.5 years for hip/knee implants and 2.5 yrs for pelvic reconstructions (range 1–6.8 yrs). Minimum follow-up of two years was available in 11 cases. Results. Infection recurred in one of the six cases managed for infection, requiring further treatment but allowing retention of the porous tantalum implant. All the patients showed well-fixed and functioning implants at latest follow-up. Conclusion. Porous tantalum has been very successful at early follow-up in patients with severe bone loss following primary and revision tumor-related surgery of the pelvis and lower extremity. Longer follow-up is required to appreciate long-term shortcomings

Aim. Femoral or tibial massive bone defects (AORI F2B-F3 / T2B-T3) are common in septic total knee replacement. Different surgical techniques are described in literature. In our study we show clinical and radiological results associated with the use of tantalum metaphyseal cones in the management of cavitary bone defects in two-stage complex knee revision. Method. Since 2010 we have implanted 70 tantalum metaphyseal cones associated with constrained or semiconstrained knee prostheses in 47 patients. The indication for revision was periprosthetic knee infection (43 cases, 91.5%) or septic knee arthritis (4 patients, 8.5%) with massive bone defect. All cases underwent a two-stage procedure. Patients were screened for main demographic and surgical data. Clinical and radiological analysis was performed in the preoperative and at 3,6 months, 1 years and each year thereafter in the postoperative. The mean follow-up was 31.1 months ± 18.8. No dropout was observed. Results. Objective and subjective functional scores (KSS, OKS) showed a statistically significant improvement from the preoperative to last follow-up (p <0.001). All cones but one (98.6%) showed radiological osteointegration. We did not find any cone-related intraoperative or postoperative mechanical complication with a 100% survival rate when we consider aseptic loosening as cause of revision. Six non progressive radiolucencies were observed. Two septic failures (4.3%) with implant and cone removal were reported. Conclusions. The ideal treatment for cavitary bone defects in two-stage TKA septic revision is still unclear. The use of metaphyseal tantalum cones showed excellent clinical and radiographic results with a low rate of related complications. The main finding of our study is the cone-related infection rate (2.9%) in this particular series of patients. This data is comparable or better than other previous report about this topic with unhomogeneous cohort of patients

Introduction. A variety of porous coatings and substrates have been used to obtain fixation at the bone-implant interface. Clinical studies of porous tantalum, have shown radiographically well-fixed implants with limited cases of loosening. However, there has been limited retrieval analysis of porous tantalum hip implants. The purpose of this study was to investigate factors affecting bone ingrowth into porous tantalum hip implants. Methods. 126 porous tantalum acetabular shells and 7 femoral stems, were collected under an IRB-approved multicenter retrieval program. Acetabular shells that were grossly loose, cemented or complex revisions were excluded. Shells with visible bone on the surface were chosen. 20 acetabular shells (10 primary) and all femoral stems were dehydrated, embedded, sectioned, polished and bSEM imaged (Figure-1). Main shell revision reasons were infection (n=10,50%), femoral loosening (n=3,15%) and instability (n=3,15%). Analyzed implants were implanted for 2.3±1.7 years (shells) and 0.3±0.3 years (stems). Eight slices per shell and 5–7 slices per stem were analyzed. The analysis included bone area/pore area (BA/PA), BA/PA zonal depth analysis, extent of ingrowth and maximum depth of bone ingrowth. BA/PA zone depths were: Zone-1 (0–500um), Zone-2 (500–1000um) and Zone-3 (1000um-full depth). Nonparametric statistical tests investigated differences in bone measurements by location within an implant and implant type (Friedman's Variance and Kruskal-Wallis). Post-hoc Dunn tests were completed for subsequent pairwise comparisons. Spearman's rank correlation identified correlations between bone measurements and patient related variables (implantation time, age, height, weight, UCLA Activity Score). Statistical analyses were performed using PASW Statistics package. Results. BA/PA was not significantly different between acetabular shells (3.6±3.3%) and femoral stems (5.8% ± 3.9%, p=0.068). Extent of ingrowth was similar between shells (42 ± 28%) and stems (47±26%, p=0.825). Acetabular shells (76±23%) and stems (82±23%, p=0.707) had a similar maximum ingrowth depth. There were 9 shells and 2 stems (Figure-2) with full bone ingrowth into the porous tantalum substrate. When bone did not bridge the entire depth, a superficial layer of dense trabecular bone integrated with the porous layer was often observed. Localized regions of increased ingrowth were observed around screw holes. BA/PA in the superior region (4.1±2.4%) of the acetabular shells was significantly higher than in the inferior region (2.0±2.1%, p=0.047, Figure-3). Acetabular shells BA/PA in Zone-1(10.8%) was significantly higher than Zone-2 (4.9%, p=0.013) and Zone-3 (1.6%, p<0.001). BA/PA was significantly higher in Zone-1 (10.8%) than Zone-3 (2.3%, p=0.043) for femoral stems. There were no correlations between patient variables and bone measurements. Discussion. Our results demonstrate that bone ingrowth in porous tantalum hip components is concentrated in the superficial 500 um (Zone-1). This may provide the opportunity to reduce the thickness of the porous layer thus conserving more bone in future designs. Bone ingrowth in the acetabular shells was preferentially located around screw holes and superior region, similar to previous studies of other cementless designs. Only 40% of analyzed acetabular shells had implantation times greater than 2 years. Further work focused on longer term retrievals will increase understanding of the bone-implant interface. This study was supported by Zimmer and NIH (NIAMS) R01 AR47904

In revision total hip arthroplasty (THA), acetabular reconstruction while dealing with severe bone loss is a challenge. The porous tantalum revision acetabular shells have been in use for the past decade. Several reports have documented successful use at early to mid-term follow up. There is, however, very little literature around the long-term survival and quality of life outcome with the use of these shells. We reviewed the results of 46 acetabular revisions with Paprosky 2 and 3 acetabular bone defects reconstructed with a hemispheric, tantalum acetabular shell and multiple supplementary screws. There were 31 females. Average age at revision was 64 years (range 23–85 years). The mean and median follow up was 11 years (range 10–12 years, SD 1). Morselised femoral allograft was used in 34 hips to fill contained cavitary defectes. Bulk femoral allografting was performed in 2 hips. At a minimum follow-up of 10 (range 10–12) years, the survivorship of the porous tantalum acetabular shell, with revision of the shell as end point was 96%. The minimum 10-year survivorship with hip revision for any reason as end point was 92%. We noted excellent pain relief (mean WOMAC pain 92.6) and good functional outcome (mean WOMAC function 90.3, mean UCLA 5); and generic quality of life measures (mean SF-12 physical component 48.3; mean SF-12 mental component 56.7). Patient satisfaction with pain relief, function and return to recreational activities were noted to be excellent. Cementless acetabular revision with the tantalum acetabular shell demonstrated excellent clinical and quality of life outcomes at minimum 10-year follow-up. As far as we are aware this is the first report of minimum 10-year follow up of use of this technique for revision hip arthroplasty

Uncemented acetabular component fixation remains the gold standard for managing various defects in the revision hip setting. Multiple series have demonstrated over 90% ten-year survivorship of these constructs. Modern “enhanced” metals such as trabecular tantalum and titanium continue to perform well and are growing in popularity. So called “jumbo” cups, diameters >=62mm in females and >=66mm in males have demonstrated excellent survivorship. Good bony support with viable bone and stable initial fixation is necessary for long-term success. It is unknown how much remaining bone is necessary for reliable ingrowth with modern enhanced metals. The location of the remaining bone is probably more important than the absolute amount remaining. Occasionally, the uncemented cup must be augmented with metal augments or even a so-called “cup cage” construct. Even in these situations, the uncemented cup remains the workhorse of revision THA due to its ingrowth potential and excellent track record. Augments are commercially available in various shapes and sizes to assist in the management of cavitary, segmental and combined defects while restoring the desired cup position. Trials are available to ensure good approximation of the augment to remaining bone. The constructs are typically “unitised” to the cup via bone cement. Available data show excellent survivorship of augmented constructs for these challenging reconstructions

Introduction. Initial large-scale clinical studies of porous tantalum implants have been generally promising with well-fixed implants and few cases of loosening [1–3]. An initial retrieval study suggests increased bone ingrowth in a modular tibial tray design compared to the monoblock design [4]. Since micromotion at the bone-implant interface is known to influence bone ingrowth [5], the goal of this study was to determine the effect of implant design, bone quality and activity type on micromotion at the bone-implant interface, through FE modeling. Patients & Methods. Our case-specific FE model of bone was created from CT data (68 year-old female, right tibia, Fig-1). Isotropic properties of cortical and trabecular bone were derived from the calibrated CT data. Modular and monoblock porous tantalum tibial implants were virtually placed in the tibia following surgical guidelines. All models parts were 3D meshed with 4-noded tetrahedral elements (MSC.MARC-Mentat 2013, MSC Software Corporation, USA). Frictional contact was applied to the bone-tantalum interface (µ=0.88) and UHWMPE-Femoral condyle interface (µ=0.05) with all other interfaces bonded. Loading was applied to simulate walking, standing up and descending stairs. For each activity, a full load cycle [6] was applied to the femoral condyles in incremental steps. The direction and magnitude of micromotions were calculated by tracking the motions of nodes of the bone, projected onto the tibial tray. Micromotions were calculated parallel to the implant surface (shear), and perpendicularly (tensile). We report the maximum (resultant) micromotion that occurred during a cycle of each activity. The bone properties were varied to represent a range in BMD (−30%BMD, Norm, +30%BMD). We compared design type, bone quality and activity type considering micromotion below 40 µm to be favorable for bone ingrowth [5]. Results. The modular tibial tray showed lower shear micromotion than the monoblock design for shear micromotion (Fig-2). Tensile micromotion was similar between the two designs (Fig-2). Lower bone quality resulted in higher shear micromotion for the modular tibial tray design. The effect of lower bone quality on shear micromotion was less apparent for the monoblock tibial tray design. For both designs, change in the bone quality had minimal effect on the tensile micromotion. For both designs, standing up and descending stairs showed lower micromotion than walking for both the tensile and shear micromotion (Fig-3). The monoblock design showed higher micromotion for standing up and descending stairs compared to the modular design (Fig-3). Discussion. In our analysis, activity type had the highest effect on micromotion. Additionally, the modular design showed lower shear micromotion than the monoblock. Although the designs were similar for the the modular and monoblock implants, the difference in micromotion, representing the initial stability of the implant, may partially explain why retrieved modular porous tantalum tibial trays had higher bone ingrowth than the monoblock design

Uncemented acetabular component fixation remains the gold standard for managing various defects in the revision hip setting. Multiple series have demonstrated over 90% ten-year survivorship of these constructs. Modern “enhanced” metals such as trabecular tantalum and titanium continue to perform well and are growing in popularity. So called “jumbo” cups, diameters >=62mm in females and >=66mm in males have demonstrated excellent survivorship. Good bony support with viable bone and stable initial fixation is necessary for long-term success. It is unknown how much remaining bone is necessary for reliable ingrowth with modern enhanced metals. The location of the remaining bone is probably more important than the absolute amount remaining. Occasionally, the uncemented cup must be augmented with metal augments or even a so-called “cup cage” construct. Even in these situations, the uncemented cup remains the workhorse of revision THA due to its ingrowth potential and excellent track record. Augments are commercially available in various shapes and sizes to assist in the management of cavitary, segmental and combined defects while restoring the desired cup position. Trials are available to ensure good approximation of the augment to remaining bone. The constructs are typically “unitised” to the cup via bone cement. Available data show excellent survivorship of augmented constructs for these challenging reconstructions

Introduction. RSA is widely accepted as a precise method to asses wear and migration early in the postoperative period. In traditional RSA, one segment defines both the acetabular shell and the polyethylene liner. However, inserting beads into the liner permits employment of the shell and liner as two separate segments, thus enabling distinct analysis of the precision of three measurement methods in determining wear and acetabular shell migration. The purpose of this in vivo follow-up study was to determine if assigning the shell and liner as one combined, or two individual segments affected the precision of RSA measurements of wear and shell stability. Methods. The UmRSA program was used to analyze the double examinations of 51 hips to determine if there was a difference in precision among 3 measurement methods: the shell only, the liner only, and the shell + liner combined segment. Tantalum beads were inserted into the liner and pelvic bone surrounding the shell intraoperatively for the purpose of RSA. Polyethylene wear was measured using point motion of the center of the head with respect to 3 different segments: 1) liner only, 2) the shell only and, 3) shell + liner segment. Cup stability was measured by segment motion comparing the stable pelvic segment to 1) the liner segment, 2) the shell only segment, and 3) the shell + liner segment. The Wilcoxon paired signed-ranks test was used to determine differences in condition number and bead counts among the 3 measurement methods (p ≤0.05). Results. The 95% confidence interval, calculated from double examinations, established the precision of each method. The shell + liner and liner only methods had a precision of 0.03mm when measuring both wear and shell migration. The shell only method precision was 0.07mm when measuring wear and 0.08mm when measuring shell migration, making it the least desirable method. In both the wear and migration analyses, the shell + liner condition number was significantly lower and the bead count was significantly higher than those of the shell only and liner only methods, indicating a superior RSA analysis on all counts compared to the shell only and liner only methods. Discussion. Insertion of beads in the polyethylene improves the precision of wear and shell migration measurements. A greater dispersion and number of beads when combining the liner with the shell generated more reliable results in both analyses by engaging a larger portion of the radiograph. The liner beads also allow measurement of cup rotation of the shell + liner segment, which is not possible when using the shell segment alone, due to the 2D nature of the program's algorithm to detect the edge of the cup. As the prediction of implant survivorship in the early postoperative period relies heavily upon RSA, it is crucial to use the most precise system to monitor these implants and the shell+ liner method meets that standard

Roentgen Stereophotogrammetric Analysis (RSA) is the gold standard for measuring implant micromotion thereby predicting implant loosening. Early migration has been associated with the risk of long-term clinical failure. We used RSA to assess the stability of the Australian designed cementless hip stem (Paragon TM) and now report our 5-year results. Fifty-three patients were prospectively and consecutively enrolled to receive a Paragon hip replacement. Tantalum beads were inserted into the bone as per RSA protocol and in the implant. RSA x-rays were taken at baseline 1–4 days post-surgery, at 6 weeks, 6 months, 12 months, 2 years, and 5 years. RSA was completed by an experienced, independent assessor. We reported the 2-year results on 46 hips (ANZJS 91 (3) March 2021 p398) and now present the 5-year results on 27 hips. From the 2-year cohort 5 patients had died, 8 patients were uncontactable, 1 patient was too unwell to attend, 5 patients had relocated too far away and declined. At 5 years the mean axial subsidence of the stem was 0.66mm (0.05 to 2.96); the mean rotation into retroversion was 0.49˚ (−0.78˚ to 2.09˚), rotation of the stem into valgus was −0.23˚ (−0.627˚ to 1.56˚). There was no detectable increase in subsidence or rotation between 6 weeks and 5 years. We compared our data to that published for the Corail cementless stem and a similar pattern of migration was noted, however greater rotational stability was achieved with the Paragon stem over a comparable follow-up period. The RSA results confirm that any minor motion of the Paragon cementless stem occurs in the first 6 weeks after which there is sustained stability for the next 5 years. The combination of a bi-planar wedge and transverse rectangular geometry provide excellent implant stability that is comparable to or better than other leading cementless stems

Introduction. Cementless Total Knee Replacement (TKR) was introduced to improve the longevity of implant; but has yet to be widely adopted because of reports of higher earlier failures in some series. The cementless TKR design has evolved recently and we have been using cementless component – both femoral and tibial on our patients. The long follow-up for fully TKR has been scarce in the literature. The purpose of this study isto investigate the minimum of ten years clinical and radiographic result of cementless titanium component and cementless tantalum component in primary TKR. Material & method. From 2008 to 2010 317 TKR underwent primary total knee with cementless femoral component titanium based (Zimmer Nexgen) and cementless tantalum component monoblock tibial component, The surgery was performed mainly on younger patients - average age was 48 yrs old ranging from 26 yrs old to 62 yrs old. All surgeries were performed by single surgeon. All patients were followed clinically and radiographically for a minimum of 8 yrs. Mean 7.8 years and range from 7 to 9 years. The underlying diagnosis for majority of the cases were degenerative arthritis in 97 of the cases and rheumatoid arthritis on the 3%. Result. We have revised 6 cases − 3 cases were for sepsis. They were revised in 2 stages. And we also revised 5 cases for loosening of femoral component. The tibial component revision for aseptic loosening or osteolysis for an end point for survivorship was a 100% for the tibia monoblock design. There was no radiographic evidence of tibial component loosening or subsidence, or migration at the time of the latest follow-up for tibia monoblock. On the femoral part we documented 16 cases other than those 4 revision for osteolysis, where limited osteolysis happened in some area of the tibial component but it did not affect stability and those has been followed up for a longer term. There was interesting phenomena in some of those cases where bone growth happened around the anterior cortex where it sealed the component entirely. Knee society scores improved from 51 pre-operatively to 94 pre-operatively on the last clinical visit. We had 32 cases where the patientswere able to regain their full mobility flexion of over 150 degrees. Conclusion. Our data clearly shows that the cementless TKR has excellent result as compared to the cemented with a good survival ship at 10 years. The tantalum tibial component shows an excellent survivorship. The femoral component also present reasonably good result but we still faced a few cases of loosening. The functional outcome for the implant with the surgery was satisfactory. With this result we strongly recommend using the cementless implant in young patients. We believe that cementless tibial is totally safe at this point as well as the femoral cementless prosthesis. However, we expect some improvement with the outcome with the femoral component when using the tantalum

Background. Core decompression (CD) is effective to relieve pain and delay the advent of total hip arthroplasty (THA) for osteonecrosis of the femoral head (ONFH). However, the influence of CD on the subsequent THA has not been determined yet. Methods. Literatures published up to and including November 2018 were searched in PubMed, Embase and the Cochrane library databases with predetermined terms. Comparative studies of the clinical outcomes between conversion to THA with prior CD (the Prior CD group) and primary THA (the Control group) for ONFH were included. Data was extracted systematically and a meta- analysis was performed. Results. Overall, five retrospective cohort studies with 110 hips in the Prior CD group and 237 hips in the Control group were included and all the studies were of high quality in terms of Newcastle-Ottawa Scale. No difference in the rate of revision between the two groups showed (RR=1.92, P=0.46) after a minimal two-year follow-up. Postoperative Harris Hip Score were similar between the two groups in all the five studies. Two groups went through similar blood loss (P=0.38). But the operative time in the Prior CD group with tantalum rob was longer than that in the Control group (P=0.006, P<0,001, respectively in two papers). Moreover, intraoperative fracture and osteolysis or radiolucent lines were more likely to occur in the Prior CD group, though there is not statistical difference (RR=7.05, P=0.08; RR=3.14, P=0.05, respectively). Conclusion. The present evidence indicated that prior CD has no inferior effect on the survivorship nor hip scores to the subsequent THA. The operative time in the Prior CD group with tantalum rob was longer than that in the Control group. Attention should also be paid on possible more intraoperative fracture and postoperative osteolysis or radiolucent lines. For any figures or tables, please contact authors directly

Massive bone loss on both the femur and tibia during revision total knee arthroplasty (TKA) remains a challenging problem. Multiple solutions have been proposed for small osseous defects, including morselised cancellous bone grafting, small-fragment structural allograft, thicker polyethylene inserts, and the use of modular augments attached to revision prosthetic designs. Large osseous defects can be treated with structural allografts, impaction bone-grafting with or without mesh augmentation, custom prosthetic components, and specialised hinged knee components. The metaphyseal area of the distal femur and proximal tibia is a particularly attractive option during revision TKA given that it is usually undamaged and well-vascularised. While multiple reconstructive options have been recommended, porous tantalum metaphyseal cones have the advantage of improved biologic fixation because of their high porosity (75–80%), interconnected pore space, and low modulus of elasticity (3 MPa) similar to that of cancellous bone. Such features allow tantalum cones to fill bone defects while tolerating physiological loads. Indications for porous tantalum metaphyseal cones include patients with Anderson Orthopaedic Research Institute Type 2B or greater defects. The surgical technique is simpler than structural allograft reconstructions with decreased preparation time, resulting in a possible decrease in infection rates. The modularity of porous tantalum metaphyseal cones also allows the surgeon to choose a size and position that best fits the individual defect encountered. Moreover, tantalum cones can be used with several revision systems. Short-term clinical follow up indicates that porous tantalum metaphyseal cones effectively provide structural support with the potential for long-term biologic fixation and durable reconstructions

Background:. Glenoid component loosening remains as an unsolved clinical problem in total shoulder arthroplasty. Current clinical assessment relies on subjective quantification using a two-dimensional plane X-ray image with arbitrarily defined criteria. There is a need to develop a readily usable clinical tool to accurately and reliably quantify the glenoid component motion over time after surgery. A high-resolution clinical CT has the potential to quantify the glenoid motion, but is challenged by metal artifact from the prosthetic humeral components. The objective of this study is to demonstrate the feasibility of using a clinical CT reconstruction to quantify the glenoid implant motion with the aid of tantalum markers. Methods:. Three spherical tantalum markers of 1.0 mm in diameter were inserted into three peripheral pegs of an all polyethylene glenoid component. The glenoid component was implanted in a sawbone scapula. To determine the effect of metal artifact on quantification of glenoid implant motion, two sawbone humerii were used: one without the prosthetic humeral components and the other with the prosthetic humeral head and stem. Three custom-made translucent spacers with the uniform thickness were placed between the glenoid component and the scapula to produce a gradual translation of the glenoid component from 1 mm to 3 mm. Before and after inserting each spacer, the surface of the glenoid component was digitized by a MicroScribe. The surface points were used to fit a sphere and the corresponding center of the sphere was calculated. The actual translation of the glenoid component was measured as the three-dimensional (3D) distance between the center of the sphere before and after insertion of each spacer. Then, the shoulder model was scanned by a clinical CT with and without the spacers for both humerii conditions. Velcro straps were used to secure the humerus to the glenoid component between the trials. All CT scans were reconstructed in VolNinja software to superimpose the scapula positions (Figure 1). The three tantalum markers were visualized and the center coordinates of the markers were used to measure the 3D distance before and after insertion of each spacer. The accuracy was defined by the difference between the averaged 3D distance measured by CT reconstruction and that measured by the MicroScribe. The standard deviation of the 3D distance measured by each tantalum marker was calculated to evaluate the reliability of the tantalum marker visualization. Results:. Without metal artifact, the accuracy and reliability of quantifying glenoid implant motion using a clinical CT were 0.4 mm and 0.2 mm, respectively (Figure 2). With the presence of metal artifact, the accuracy and reliability were 0.5 mm and 0.4 mm, respectively. The largest difference in quantifying the glenoid component motion with and without the metal artifact was only 0.12 mm. Conclusion:. The current study demonstrated the feasibility of using a clinical CT to quantify glenoid implant motion. With the aid of tantalum markers, a clinical CT can be readily used to quantify the glenoid implant motion accurately and reliably even with the presence of metal artifact from the humeral components