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

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

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. 3 main challenges encountered in knee revision of Asians:. systemic: such as osteoporosis and laxity. anatomical variance: established in literature making revision system not appropriate. Neglected case revised late owes to extensive bone loss demanding bone substitute and increased constrain. Therefore we like to alert surgeon apprehending enhanced challenges while indulging in revision of Asian. Our emiratus author with USA background/qualification/experience has excuted 216 revision in 8yrs with at least 3yrs follow-up. Material & Method. Between 2003–2010 we performed 216 revision TKR, reviewed all parameters & compared our results with European revision statistics depicting a) intermedullary canal smaller b) metaphysis narrower & more triangular in comparision to Caucasian causing housing mechanism fit impossible, also increase impingment of stem at times. Bone loss is normally quiet extensive & available implant including the Tantalum cone sometimes is difficult to fit in a tight metaphyseal area, we had satisfactory outcome inspite of owing to intra-operative complication which lead to 3 intramedullary fracture resulting from inadequate avalibity of smaller size, incomplete seating of tibial component, overhang of femoral component.it also leads to more translucent line quoted in 15 cases. Centre of IM canal in both tibia & femur is positioned more posteriorly especially in smaller size proven by CT anatomical study analysis. These data we related to anatomic variance rather then surgical technique therefore representing deficit of proper size thereby contributing to inability to surgeon. Conclusion. Restoring joint line to tibia to prevent impingment of tibial housing is crucks, enabled by utilizing certain surgical tricks which all surgeon revising small stature Asian should bear in mind.in certain instances use totally cemented stubby stem. 2 important aspect of our abstract:. a). Present: we will review all tricks enabling appropriate/maximum utilization of inadequate current revision system. b). Future: we will also present specific recommendation to Industry based on anatomy variation alerting them need of. 1). asymmetrical tibial component. 2). natural femoral component. 3). repositioning of stem. Multiple factors contributes more challenges in Asian revision:. 1). mainly anatomy attributed to metaphyseal morphology. 2). unable to apply certain surgical tricks to fit implant in small patient. strong recommendation to Industry to alter revision system inorder to achieve more success in Asian revision surgery

Restoration of bone loss is a major challenge of revision TKA surgery. It is critical to achieve of a stable construct to support implants and achieve successful results. Major bone defects of the femoral and/or tibia (AORI type IIB/III) have been reconstructed using impaction grafting, structural allografts or tumor prostheses. The major concerns with structural allograft are graft resorption, mechanical failure, tissue availability, disease transmission, considerable surgical skill required and prolonged operative time. Porous tantalum metaphyseal cones, are becoming the established method of choice to correct large bone defects with several recent studies demonstrating promising results. The high coefficient of friction of these implants provides structural support for femoral and tibial components. The high degree of porosity has excellent potential for bone ingrowth and long-term biologic fixation. Several published series, although with relatively small cohorts of patients, have reported good short-term results with trabecular metal cones for major femoral and tibial bony defects in revision TKA. In a recent study, 16 femoral and 17 tibial cones were reviewed at an average follow up of 33 months (range, 13 to 73 months) the mean Knee Society Score improved from 42 pre-operatively to 83 at last follow up with an improvement of the functional score from an average of 34 to 66 (p<0.0001). Radiological follow up revealed no evidence of loosening or migration of the constructs. No evidence of complications were noted in correlation with the use of trabecular metal cones

Aims

Metaphyseal tritanium cones can be used to manage the tibial bone loss commonly encountered at revision total knee arthroplasty (rTKA). Tibial stems provide additional fixation and are generally used in combination with cones. The aim of this study was to examine the role of the stems in the overall stability of tibial implants when metaphyseal cones are used for rTKA.

The December 2015 Knee Roundup360 looks at: Albumin and complications in knee arthroplasty; Tantalum: a knee fixation for all seasons?; Dynamic knee alignment; Tibial component design in UKA; Managing the tidal wave of revision knee arthroplasty; Scoring pain in TKR; Does anyone have a ‘normal’ tibial slope?; XLPE in TKR? A five-year clinical study; Spacers and infected revision arthroplasties; Dialysis and arthroplasty

The April 2014 Knee Roundup³⁶⁰ looks at: mobile compression as good as chemical thromboprophylaxis; patellar injury with MIS knee surgery; tibial plateau fracture results not as good as we thought; back and knee pain; metaphyseal sleeves may be the answer in revision knee replacement; oral tranexamic acid; gentamycin alone in antibiotic spacers; and whether the jury is still out on unloader braces.