Trabecular Metal Cones Research Articles

Metaphyseal cones combined with diaphyseal impaction grafting provide good outcomes and survival in a complex revision total knee arthroplasty: a matched comparative analysis.

To compare clinical and radiological outcomes, implant survivorship at a minimum of 1-year follow-up using metaphyseal trabecular cones with or without impaction grafting in a complex revision TKA. A retrospective comparative matched analysis was performed and 15 patients who underwent revision surgery using the combination of porous trabecular metaphyseal cone and diaphyseal impaction grafting (MC-IBG) were matched with a group of 13 patients who also underwent revision surgery using metaphyseal cone (MC) without impaction grafting. All included patients presented severe bone defect (AORI 2,3) and a rotating-hinge prosthesis were implanted. Both groups were comparable regarding the baseline demographic and clinical data. Patients had previously undergone a mean of 4 (range, 2-12) and 3 (range, 2-5) previous proceduresin the MC-IBG and MC groups, respectively. The indications for revision were aseptic loosening in 11 (73.3%) and 11 (84.6%) patients; prosthetic joint infection in 4 (26.7%) and 2 (15.4%) in the MC-IBG and MC groups, respectively. There was no significant difference in the mean postoperative Knee Society Score between the study groups (p = 0.806). Overall, 4 patients had further revision. Two patients were revised in the MC-IBG group, one patient for aseptic loosening and the second one after 2 episodes of instability. Two patients in the MC group presented prosthetic joint infection and underwent a two-stage reimplantation. No significant difference was observed between the study groups at comparison (p = 0.92). Trabecular metal cones with diaphyseal impaction grafting provide an alternative technique in acomplex revision TKAsurgery with early clinical and radiographic success.

Is hybrid fixation in revision TKA using LCCK prostheses reliable?

IntroductionThe optimal technique for component fixation in revision total knee arthroplasty (rTKA) remains controversial: full cementation (FC) versus hybrid fixation (HF), which involves press-fit stem with cement fixation in the metaphyseal and epiphyseal zones. Previous series have either demonstrated the superiority of one or the other of these techniques or their equivalence. However, few studies have compared these 2 methods for rTKA using the Legacy® Constrained Condylar Knee (LCCK) prosthesis (Zimmer, Warsaw, Indiana, USA). HypothesisOur hypothesis was that HF of LCCK components is associated with a higher rate of aseptic loosening (AL) than FC. Materials and methodsThis was a single-center, multi-surgeon, retrospective study. Primary revisions between January 2010 and December 2014 were included for all indications. The only exclusion criterion was death without revision before the 5-year follow-up. The primary objective of this study was to compare the survivorship of 2 groups of LCCK components (femoral or tibial), depending on whether their stems had been cemented (HF versus FC), taking AL, revised or not, as the endpoint. The secondary objective was to look for other predictive factors of AL. ResultsA total of 75 rTKAs (150 components) were included. The FC group (51 components) had more Anderson Orthopedic Research Institute (AORI) type 2B and type 3 bone defects (BDs) (p<0.001), more reconstructions using trabecular metal (TM) cones (19 FCs and 5 HFs; p<0.001), and bone allografts (p<0.001). At more than 5 years, none of the FC components were loose compared to 10 HF components (9.4%), with 4 of these stems revised. The only significant difference was survivorship without radiographic AL at 9 years (FC=100%; HF=78.6%; p=0.04). The only predictive factor of AL in the HF group was the filling of the diaphyseal canal (p<0.01). The detrimental effect of BD severity (p=0.78) and the protective effect of TM cones were not demonstrated (p=0.21). DiscussionOther series studying revisions using the same type of prosthesis also concluded the superiority of FC, not found for other revision prostheses. Despite this study's limitations (retrospective, multi-surgeon, limited sample size, and limited follow-up), all patient outcomes were known, and the difference in survivorship between the groups was very significant. ConclusionHF has not been proven effective for the LCCK prosthesis. Better diaphyseal filling, wider metaphyseal bone tunnels enabling better cement injections, and stem designs more appropriate for press-fit fixation could improve these results. TM cones are an interesting avenue for further research. Level of evidenceIII; retrospective comparative study.

TIBIAL METAPHYSEAL CONES COMBINED WITH SHORT STEMS PERFORM AS WELL AS LONG STEMS IN REVISION TOTAL KNEE ARTHROPLASTY

Little information exists regarding optimal tibial stem usage in revision total knee arthroplasty (rTKA) utilising a tibial trabecular metal (TM) cone. The purpose of this study was to compare 1) functional outcomes, 2) radiographic outcomes, and 3) implant survivorship in rTKA utilising TM cones combined with either short stems (SS) or long stems (LS) at minimum two-years clinical follow-up.In this retrospective, multi-centre study, patients undergoing TM cone utilising rTKA between 2008 and 2019 were included. Patients were divided into: SS group (no diaphyseal engagement), and LS group (diaphyseal engagement). All relevant clinical charts and post-operative radiographs were examined. Oxford Knee Score (OKS) and EuroQol-5D (EQ-5D-5L) data were collected at most recent follow-up.In total, 44 patients were included: 18 in the SS group and 26 in the LS group. The mean time of follow-up was 4.0 years. Failure free survival was 94.5% for the SS group and 92.3% for the LS group. All failures were for prosthetic joint infections managed with debridement, antibiotics, and implant retention. At most recent follow-up, 3 patients demonstrated radiographic signs of lucency (1 SS 2 LS, p = 1) and the mean OKS were 37 ± 4 and 36 ± 6 (p = 0.73) in the SS and LS groups, respectively.Tibial SS combined with TM cones performed as well as LS in rTKA at minimum two-years follow-up. A tibial SS in combination with a TM cone is a reliable technique to achieve stable and durable fixation in rTKA.

Tibial metaphyseal cones combined with short stems perform as well as long stems in revision total knee arthroplasty

BackgroundsThere is uncertainty around optimal tibial stem length in revision total knee arthroplasty (rTKA) utilizing a tibial trabecular metal (TM) cone. The purpose of this study was to compare: (1) functional outcomes, (2) radiographic outcomes and (3) implant survivorship in rTKA utilizing TM cones combined with either short stems (SS) or long stems (LS) at minimum 2 years follow‐up.MethodsIn this retrospective, multi‐centre study, patients undergoing rTKA utilizing a TM cone between 2008 and 2019 were included. Patients were divided into: SS group (no diaphyseal engagement), and LS group (diaphyseal engagement). All relevant clinical charts and post‐operative radiographs were examined. Oxford Knee Score (OKS) and EuroQol‐5D (EQ‐5D‐5L) data were collected at most recent follow‐up.ResultsIn total, 44 patients were included: 18 in the SS group and 26 in the LS group. The mean time of follow‐up was 4.0 years. Failure free survival was 94.4% for the SS group and 92.3% for the LS group. All failures were for prosthetic joint infections managed with debridement, antibiotics, and implant retention. At most recent follow‐up, 3 patients demonstrated radiographic signs of lucency (1 SS 2 LS, P = 1) and the mean OKS were 37 ± 4 and 36 ± 6 (P = 0.73) in the SS and LS groups, respectively.ConclusionTibial SS combined with TM cones performed as well as LS in rTKA at minimum 2 years follow‐up. A tibial SS in combination with a TM cone is a reliable technique to achieve stable and durable fixation in rTKA.

Midterm Radiographic Results and Reoperations of Tantalum Trabecular Metal Cones in Knee Arthroplasties.

Objective The management of bone loss represents a challenge in revisions of total knee arthroplasty (rTKA) and in complex primary total knee arthroplasties (TKAs). The purpose of the present study was to evaluate the midterm outcomes (5-year minimum follow-up) of knee reconstructions with tantalum trabecular metal (TM) cones on bone defects Anderson Orthopaedics Research Institute (AORI) 2 and 3. Materials and Methods A retrospective analysis of the medical records of patients operated on between July 2008 and November 2014 was performed, collecting the following data: age, gender, laterality, body mass index, etiology of arthrosis, comorbidities, AORI classification of bone defects, causes for revision, readmissions, reoperations, perioperative and postoperative complications, radiographic signs of osteointegration, and maintenance of the TM support. Results A total of 11 patients with a mean follow-up of 7.28 years (standard deviation [SD] = 1.88; range = 5.12–10 years) was evaluated, with 1 patient operated upon for a primary arthroplasty, 6 for revision arthroplasties, and 4 for a second revision arthroplasty (re-revision). There were complications with the surgical wound, injury to the extensor mechanism and loosening of the femoral component in three of the patients that led to the necessity of four procedures due to complications with the surgical wound, injury to the extensor mechanism and loosening of the femoral component. Radiological signs of osteointegration of the trabecular cones were observed in all patients. We did not observe migration of the TM cones or the prosthetic components in the sample.Conclusion The tantalum metaphyseal cones were able to provide efficient structural support to prosthetic implants with radiographic signs of osteointegration in the medium term.

Usefulness of Trabecular Metal Cones in Revision Total Knee Arthroplasty in a Korean Population: A Case Series.

PurposeThe purpose of this study was to assess the medium-term results of trabecular metal cones for the reconstruction of large bone defects in revision TKA.MethodsThirteen patients who had undergone revision TKA using trabecular metal cones for femoral and/or tibial large bone defects were identified. We included patients who had a minimum of three years follow-up in the study. We evaluated their functional outcomes, implant survivorship, radiological findings, and complications.ResultsAt a mean follow-up of 6.9 years (range of 3.5–9.4 years), all trabecular metal cones and implants were well fixed and did not exhibit any radiographic evidence of migration or loosening. At the final follow-up, the mean Knee Society knee scores had improved from 37.2 to 78.1 (p < 0.05), and function scores had improved from 35.5 to 77.5 points (p < 0.05). One intraoperative fracture in the distal femur occurred in an 85-year-old woman during impaction of a single trabecular metal cone. The fracture was successfully affixed to the femoral cone and bone three months postoperatively.ConclusionThe present study of trabecular metal cones demonstrates excellent clinical outcomes and survivorship in revision TKA during medium-term follow-up periods. However, longer-term follow-up studies are needed to further investigate these implants in revision TKA. Additionally, the necessity of metal cones in revision procedures should be carefully considered depending on patient needs and economic capabilities.

Medium term clinical outcomes of tibial cones in revision knee arthroplasty.

Trabecular metal cones are a relatively new option for reconstruction of major bone defects during revision total knee arthroplasty (TKA). The purpose of the present study was to retrospectively assess medium-term results for tibial cones in revision TKA with a severe proximal tibial bone defect. We hypothesized that revision TKA patients with bone defects treated with trabecular metal cones have excellent medium-term clinical and radiological results. A single-center retrospective review included all consecutive cases of tibial revision using trabecular metal cones. All patients with a minimum 2-year follow-up were included in the study. There were no exclusion criteria. The primary endpoint was tibial cone survivorship. The secondary endpoints were revision TKA all-cause survivorship, patient-reported outcome measures with a Knee injury and Osteoarthritis Outcome Score (KOOS), SF 12, and radiographic analysis. Five of the 57 patients alive at last follow-up (8.77%) had undergone revision (4 for infection and 1 for instability). Complications comprised four cases (7.02%) of infection, 2 cases (3.51%) of tibial and femoral implant aseptic loosening that did not require revision surgery, 1 of which (1.75%) with associated patellar loosening, and 1 case (1.75%) of instability. Kaplan-Meier estimates showed 100% 5-year survivorship with tibial cone revision for aseptic loosening and 93.44% (95% CI 83.47-97.49%) for all-cause revision. The present study of cones used for tibial revision supports shows excellent results; however, longer and larger follow-up is needed to better assess results in revision TKA. 4, retrospective study.

Trabecular Metal Cones Combined With Short Cemented Stem Allow Favorable Outcomes in Aseptic Revision Total Knee Arthroplasty

BackgroundThe purpose of this study was to compare the functional outcomes and implant survivorship at a minimum of 5 years of follow-up of several reconstruction techniques with or without metaphyseal cone and stems of variable length. MethodsA retrospective comparative matched analysis was performed from 2 prospectively collected databases. Only patients who underwent revision total knee arthroplasty procedures for aseptic causes using a single design of rotating hinge knee with a minimum of 5 years of follow-up were analyzed. Patients were separated into 3 groups: trabecular metal (TM) cones + short cemented stems (TM + short stem [SS]), TM cones + long uncemented stems (TM + long stem [LS]), and no cone (NC) + long uncemented stems (NC + LS). A matching process based on age (±5 years) was realized. ResultsAbout 99 patients were included; 33 in the TM + SS group, 33 in the TM + LS group, and 33 in the NC + LS group. The mean time of follow-up was 9.3 years. A significant difference of the improvement of subscale pain, symptom, activities of daily living, quality of life of the Knee Injury and Osteoarthritis Outcome score and knee, function of the Knee Society Score was observed in favor of TM + SS group compared with the 2 other groups. At 8 years of survivorship, the components free of revision for any cause were 90.9% for the TM + SS group, 84.9% for the TM + LS group, and 90.6% for the NC + LS group. ConclusionThe use of a short cemented tibial stem combined with a TM cone in revision total knee arthroplasty offers identical survival rate with better functional outcome compared with the use of a long uncemented stem associated with TM cones or metallic augments at a minimum of 5 years of follow-up.

Treatment of periprosthetic fractures of the knee using trabecular metal cones for stabilization.

This report describes an operative technique for the treatment of periprosthetic fractures of the knee with instability of the metaphysis and the metadiaphyseal junction that stabilizes the metaphyseal fragment by a distraction technique using trabecular metal cones. Fifteen patients were examined clinically and radiologically for a follow-up period of 36.7 ± 8.7 months. The Knee Society Score improved to 73.2 ± 20.2 by 24 months after surgery; the function score improved to 68.3 ± 20.2 by 24 months after surgery. The mean flexion amounted to 94.4 ± 9.7 degrees by 24 months after surgery. The only complication was one case of thrombosis. This technique involving trabecular metal cones to stabilize metaphyseal fractures seems to represent a further option for fixation of periprosthetic fractures that are otherwise treated with megaprostheses.

Stacked Tantalum Cones as a Method for Treating Severe Distal Femoral Bone Deficiency in Total Knee Arthroplasty.

Severe bone loss in distal femur has traditionally been managed with bulk cementing, bone graft, metal augments, trabecular metal cones, and mega prosthesis. The authors present an alternative method using a stacked configuration of two tantalum cones to manage severe distal femoral bone loss. This study aims to evaluate the mid-term outcomes and possible complications in patients treated with this novel technique. We retrospectively analyzed the prospectively maintained records of 16 knees (in 16 patients) presenting with severe distal femoral bone deficiency due to septic loosening (5), giant cell tumor (GCT; 4), periprosthetic fracture (3), aseptic loosening (3), and distal femoral comminuted fracture with severe osteoarthritis (1). A standard medial parapatellar approach was taken in all our cases followed by preparation of distal femoral bone defect and use of two bridging tantalum trabecular metal cones to fill the defect, followed by implantation of rotating hinge knee prosthesis. At an average follow-up of 57 months (4.75 years), the average Knee Society Score was 74.56 (64-87) and the mean range of motion was 97.8 (70-120) degrees. Radiologically, all 16 knees showed good osteointegration with no evidence of progressive radiolucency or loosening. Complications included two patients with superficial infection (healed with antibiotics), and one with recurrence of GCT requiring tumor megaprosthesis reconstruction. The authors concluded that the stacked configuration of cones provides additional coverage and stability with good osteointegration and found it to be particularly useful in distal femoral GCTs and fracture situations. They recommend the use of stacked cones in selected cases of severe distal femoral deficiency.

Management of large bone defects around the knee using porous tantalum trabecular metal cones during complex primary and revision total knee arthroplasty

With the rising numbers and indications of primary as well as revision total knee arthroplasty (TKA), managing bone defects around the knee is an emerging challenge. This retrospective study evaluates the outcomes of Trabecular Metal (TM) cones used to address bone defects in 79 (20 primary and 59 revision) TKA cases. Range of motion and Knee Society Score improved significantly postoperatively, with better outcomes in the primary TKA group. Complete osteointegration was observed in all the cases. At an average follow-up of 6.6 years, major complications requiring re-operation were seen in 4 (5%) knees. TM cones are an effective option for treating severe bone defects during TKA with predictable osteointegration and good long-term clinical outcomes.

Erratum to: No Difference Between Trabecular Metal Cones and Femoral Head Allografts in Revision TKA: Minimum 5-year Followup.

Erratum to: No Difference Between Trabecular Metal Cones and Femoral Head Allografts in Revision TKA: Minimum 5-year Followup.

Letter to the Editor: No Difference Between Trabecular Metal Cones and Femoral Head Allografts in Revision TKA: Minimum 5-year Followup

To the Editor, We read the article by Sandiford and colleagues [3] with great interest. Although this is a valuable study, we have some queries for the authors. In the Patients and Methods section, the authors noted that 45 TKA revisions were performed using augmentation of host bone. Of those 45, surgeons used “femoral head allograft in 30 (75%) and trabecular metal cones in 15 (25%).” Shouldn’t the percentages be 66.7% and 33.3%, respectively? In the Trabecular Metal Cone Technique section, the authors stated: “Nine Type 2A and two Type 2B femoral defects and 13 Type 2A and six Type 2B tibial defects were treated with femoral head allografts. Four Type 2B and two Type 3 femoral defects and two Type 2A and seven Type 2B tibial defects were treated using trabecular metal cones.” However, the second sentence does not match up with the data in Table 1. Are the data in the text or in Table 1 correct? In the Conclusions section, the authors state that both techniques are viable options for the management of Anderson Orthopaedic Research Institute (AORI) Type 2 and 3 defects. But in the study, no patients with Type 3 bone defects were treated with femoral head allografts. Because of this, we believe that that the study’s conclusions may be overstated as published. Finally, the authors used the Oxford Knee Score, WOMAC, SF-12, and the UCLA activity score to assess knee function and quality of life, and additionally, radiographs were assessed for signs of loosening. But radiostereometric analysis (RSA) is also important because the AORI classification referenced in the article is based on radiological images. In fact, in a study by Jensen and colleagues [2], the difference between the mean maximum total point motion of the trabecular metal cone group and the no trabecular metal cone group was almost 2 mm, but they could not detect this as a significant difference. However, in Sandiford and colleagues, perhaps there is a significant difference between the trabecular metal cone and femoral head allograft groups. If Sandiford and colleagues compared outcomes of the two groups’ images at 3 weeks, 6 weeks, 3 months, and 1 year using RSA [1], and then annually after 1 year, using the methods they used, perhaps their conclusions would have been more convincing.

Are Trabecular Metal Cones a Valid Option to Treat Metaphyseal Bone Defects in Complex Primary and Revision Knee Arthroplasty?

Purpose Metaphyseal bone defects are a challenge in complex primary and revision total knee arthroplasty (TKA). Recently, several studies have been published with promising results about the use of Trabecular Metal (TM) cones to address bone defects. The aim of this study is to review the literature to assess the efficacy of TM cones to address metaphyseal bone loss. Methods A comprehensive search was performed on PubMed, Medline, CINAHL, Cochrane, Embase, and Google Scholar databases using various combinations of the following keywords: “metaphyseal,” “cones,” “tantalum,” “knee,” and “revision.” Only papers reporting clinical data about the use of trabecular metal cones were included in the analysis. In vitro studies, case reports, surgical technique, or other studies where it was not possible to collect clinical data were excluded. Patients characteristics, details of the surgical procedures, outcome, and complications were collected from each included study. Results No controlled studies were available in the literature and all the papers were case series. In 16 studies included, the records of 442 patients with 447 implants and 523 TM cones were reported. The mean follow-up was 42 months (range: 5–105) for 360 procedures. Among 437 procedures, 30.4% were septic revisions. The Anderson Orthopaedic Research Institute (AORI) classification was available for 352 defects: 13 type 1, 69 type 2A, 115 type 2B, and 155 type 3. To manage these 352 defects, 360 TM cones were implanted. Intraoperative fractures occurred 13 times (10 femoral/3 tibial), 6 required surgical fixation. The overall infection rate was 7.38%, and the infection rate for the aseptic procedures was 0.99%. An aseptic exchange was performed 13 times, among these procedures two TM cones were loose. Signs of loosening were found just in 1.3% of the 523 TM cones implanted (5 femoral/2 tibial) during 447 procedures. Conclusion The TM cones are an effective solution to manage bone defects in complex primary and revision TKA at intermediate follow-up. The incidence of complications was low; however, the femoral metaphysis proved to be more susceptible to complications. Level of Evidence Level IV, systematic review of level IV studies.

Tibial component with and without stem extension in a trabecular metal cone construct

PurposeThe purpose of this study was to investigate stability and strain distribution of a tibial plateau reconstruction with a trabecular metal cone while the tibial component is implanted with and without a stem, and whether prosthetic stability was influenced by bone mineral density. Trabecular metal cones are designed to fill up major bone defects in total knee arthroplasty. Tibial components can be implanted in combination with a stem, but it is unclear whether this is necessary after reconstruction with a trabecular metal cone. Implanting a stem can give extra stability, but may have negative side effects.MethodsTibial revision arthroplasties with trabecular metal cones were performed after reconstruction of a 2B bone defect according to the Anderson Orthopedic Research Institute classification. Components were implanted in seven pairs of cadaveric tibiae; one tibia of each pair was implanted with stem and the other without. All specimens were loaded to one bodyweight alternating between the medial and lateral tibial component. Implant-bone micro-motions, bone strains, bone mineral density and correlations were measured and/or calculated.ResultsTibial components without a stem showed only more varus tilt [difference in median 0.14° (P < 0.05)], but this was not considered clinically relevant. Strain distribution did not differ. Bone mineral density only had an effect on the anterior/posterior tilt [ρ: −0.72 (P < 0.01)].ConclusionTibial components, with or without a stem, which are implanted after reconstruction of major bone defects using trabecular metal cones produce very similar biomechanical conditions in terms of stability and strain distribution. If in vivo studies confirm that a stem extension is not mandatory, orthopaedic surgeons can decide not to implant a stem.Level of evidenceII.

CORR Insights®: No Difference between Trabecular Metal Cones and Femoral Head Allograft in Revision TKA: Minimum 5-year Followup.

Where Are We Now? A substantial increase in the volume of primary TKA in conjunction with increases in patient lifespan has resulted in an increased need for revision TKA. An analysis of revision TKA volume in Medicare beneficiaries showed revision volume increased 105.9% from 1991 to 2010 [2]. There is some degree of bone loss associated with each revision procedure because of initial bone resection at the time of primary TKA, osteolysis from wear debris or other causes, and bone loss associated with component removal. Minor bone defects (Anderson Orthopaedic Research Institute [AORI] Types 1 and 2 [4]) are usually managed simply with cancellous cavitary bone grafting, bone cement with or without screws, or peripheral metal augments. Larger defects (AORI Types 2B and 3 [2]) make it more difficult to achieve durable implant fixation because of the loss of bone support. Historically, structural allografts have been used to reconstruct these defects, with 91% demonstrating satisfactory function in a report of 46 subjects at a mean followup duration of 97 months [5], although problems with nonunion, late graft collapse, and the potential for disease transmission have been identified [1]. These problems have resulted in the development of metaphyseal sleeves and trabecular metal cones to enhance long-term fixation [3, 6, 7]. Short-term results with these devices have been favorable but have analyzed only a single method of defect management rather than comparative studies of multiple techniques. The current report is the first to compare different techniques (structural allograft versus trabecular metal cones). The authors observed no differences in pain relief, function, or repeat revision TKA rates between patients treated with the two approaches. Where Do We Need To Go? Numerous questions remain regarding management of large bone defects in revision TKA. Will the findings of this small study, which includes a combined total of only 45 patients (30 femoral had allografts versus 15 trabecular metal cones), be confirmed in larger and more diverse revision TKA populations? Will the clinical results remain similar with longer followup duration since some reports of use of structural allografts have demonstrated failure due to graft resorption at followup intervals longer than 10 years? Should a revision TKA utilizing either of these techniques fail, what are the results of a repeat revision procedure? Does one technique result in a simpler or more complex re-revision procedure? For example, will use of a structural allograft provide restored bone stock for future revisions? Should infection occur, does an incorporated structural allograft or trabecular metal cone require total removal? How difficult is removal of a well-fixed trabecular metal cone and what are the technical tips for safe removal? Does removal of a well-fixed trabecular metal cone result in a substantial amount of retained third-body metallic debris particulate that may accelerate polyethylene wear in repeat revision procedures? Allografts can be sterilized using multiple methods; to what degree are there clinically important tradeoffs among these approaches? Will irradiation of frozen grafts to reduce disease transmission result in unacceptable reductions in mechanical strength compared to fresh-frozen allografts? Lastly, is use of modular stem extensions necessary for all revision TKA operations utilizing one or both of the techniques studied in the current evaluation? If so, how long should the stems be? Are short cemented stem extensions adequate or will longer stem extensions engaging diaphyseal bone prove more durable? How Do We Get There? Randomized comparative analyses of the two techniques with followup duration of a minimum of 10 years are necessary. While difficult to accomplish, a multicenter effort would likely be required to create a case volume adequate to draw firm conclusions. In such a study, it would be beneficial to include a third technique of using porous coated metaphyseal sleeves [3] as these are commonly used for Types 2B and 3 [2] bone defects. All Type 2B and 3 bone defects [4] are not the same. Some have more loss of cortical rim support than others. The amount of bone loss using the AORI bone defect classification [4] is variable. A more-critical evaluation of defect size and shape is necessary to better discern whether structural bone allografts or trabecular metal cones are superior in the management of specific bone defect geometries. Of course, bone defects also occur on the femur; are results different when dealing with femoral versus tibial defects? For example, Type 3 femoral defects have the potential for loss of collateral ligament support; does this influence which approach might be better? These questions and others call for larger, longer-term, randomized and likely multicenter studies. To accomplish this, economic support from national organizations such as the Knee Society and the American Association of Hip and Knee Surgeons would be helpful as their memberships contain leaders in TKA with competent databases necessary to provide the required meaningful data.

No Difference Between Trabecular Metal Cones and Femoral Head Allografts in Revision TKA: Minimum 5-year Followup.

Encouraging clinical results have been reported with the use of femoral head structural allografts and, more recently, trabecular metal cones for the management of large structural defects of the femur and tibia during revision total knee arthroplasty (TKA). However, to our knowledge, there are no published studies comparing these two techniques. Compared with bulk allografts, do trabecular metal cones result in (1) better validated outcomes scores; (2) a lower risk of loosening or revision at 5 years; and (3) fewer surgical complications when used for the management of bone loss in revision TKA? Between 2002 and 2008, three surgeons performed 450 TKA revisions, 45 (10%) of which were performed using augmentation of host bone; in those, femoral head allograft was used in 30 (75%) and trabecular metal cones in 15 (25%). From 2002 to 2007, femoral head allografts were used in all patients (28 patients); from 2007 to 2008, trabecular metal augments were used in all patients. There was a period of 1 year (16 knees) in which there was some overlap; during that time, femoral head structural allografts were used in cases in which we were unable to fit the defect or achieve adequate stability with trabecular metal cones. Followup was at a mean of 9 years (range, 5-12 years). No patients were lost to followup. Knee function and quality of life were assessed using the Oxford Knee Score, WOMAC, SF-12, and the UCLA activity score. Radiographs were assessed for signs of loosening. Surgical complications included superficial or deep infections, iatrogenic fractures, symptomatic deep venous thromboses or pulmonary emboli, and blood loss requiring transfusion; these were obtained from our database and from review of patients' charts. The mean Oxford Knee Score in the allograft and trabecular metal cone groups was 91 (SD 10) and 91 (SD 14), respectively (95% confidence interval [CI], 88-94; p = 0.29). Mean WOMAC scores were 94 (SD 10) and 92 (SD 14), respectively (95% CI, 80-105; p = 0.52) and mean UCLA scores were 6 (SD 1.2) and 6 (SD 1.5), respectively (95% CI, 4-8; p = 0.49). Five- and 10-year survivorship of the allografts was 93% (95% CI, 77-98) and 93% (95% CI, 77-99), respectively. Survivorship at a mean of 5 years in the trabecular metal cones group was 91% (95% CI, 56-98). With the numbers available, there were no differences between the groups in terms of the frequency of surgical complications (3% [one of 30] versus 7% [one of 15]; odds ratio, 0.5; p = 0.632). With the numbers available, we found no difference in pain, function, or repeat revision when comparing femoral head allografts and trabecular metal cones for severe bone defects during revision TKA. However, we used allografts for the larger bone defects. Based on these results, we believe that femoral head allografts and trabecular metal cones can both be used for the management of Anderson Orthopaedic Research Institute Types 2 and 3 defects. Future multicenter studies are required with larger numbers, cost analyses, and a longer duration of followup. Level III, therapeutic study.

The Use of Trabecular Metal Cones in Complex Primary and Revision Total Knee Arthroplasty

Trabecular metal cones are one option for treating osseous defects during TKA. A total of 83 consecutive TKAs utilizing cones with an average of 40months follow-up were reviewed. There were 24 males and 59 females, with an average age of 69years old. Four were complex primary and 79 were revision procedures. Of 83 patients, 10 (12%) required repeat revision surgery (8 infections, one periprosthetic fracture, one aseptic loosening) and overall, 37 of 83 patients (45%) experienced at least one complication. Of 73 unrevised knees, 72 (99%) demonstrated radiographic evidence of osseointegration. Despite a high complication rate in this population, trabecular metal cones represent an attractive option for managing bone loss in complex primary and revision TKA with a high rate of osseointegration.

Outcome of revision total knee arthroplasty with the use of trabecular metal cone for reconstruction of severe bone loss at the proximal tibia

The relative effectiveness of different methods for reconstructing large bone loss at the proximal tibia in revision total knee arthroplasty (rTKA) has not been established. The aim of this study was to evaluate the clinical and radiological outcome after the use of trabecular metal technology (TMT) cones for the reconstruction of tibial bone loss at the time of rTKA. Thirty-six patients had rTKA with the use of a TMT Cone. Bone loss was classified according to the AORI classification and 25% of the patients suffered from T3 AORI defects and 75% of the patients from T2 AORI defects. Implants used were from the NexGen series. At follow-up, radiographs were evaluated according to the Knee Society Roentgenographic Scoring System. Knee and function score was calculated using the Knee Society Clinical Rating System. Average follow-up time was 47 months (range 3-84 months). Clinical and radiological follow-up data were available in 30 patients and missing in six patients: two died and four patients had re-revision (reinfection (n=2), aseptic loosening (n=1), and knee hyperextension (n=1)). Knee- and function scores (follow-up 43 months (range 12-84 months)) improved from 42 to 77 points (p<0.0005) and 19 to 63 points (p<0.0005) respectively. Twenty-seven patients (follow-up 44 months (range 12-72 months)) showed no signs of radiological loosening of rTKA components. Based on our study, it was concluded that the use of TMT Cones provided an effective treatment in terms of surgical efficacy, clinical results and radiological results and was evidently at least as effective as the other options reviewed in the literature. IV.

Use of a trabecular metal cone made of tantalum, to treat bone defects during revision knee arthroplasty

Objectivesthe aim of this study was to evaluate the surgical technique and determine the initial results, with a minimum follow-up of two years, from total knee arthroplasty revisions in which trabecular metal cones made of tantalum were used at the Knee Surgery Center of the National Institute of Traumatology and Orthopedics (INTO) or at the authors’ private clinic between July 2008 and December 2010. Methodsten patients were included in the study prospectively, through clinical and radiographic evaluations. Resultsseven patients presented evolution without complications relating to the tantalum cones used. Five of these patients said that they did not have any pain and all of them were able to walk without needing crutches. In all the cases, we observed that osseointegration of the tantalum cones had occurred. No migration or loosening of the implants was observed, nor was osteolysis. Conclusionuse of trabecular metal cones made of tantalum for treating AORI type II or II bone defects was capable of providing efficient structural support to the prosthetic revision implants, in evaluations with a short follow-up.