Metaphyseal Cones Research Articles

Comparative evaluation of bone defect replacement methods in revision total knee arthroplasty

Objective: to evaluate the immediate and long-term outcomes of revision total knee arthroplasty using porous metaphyseal sleeves and cones. Materials and Methods. The study included 134 patients who underwent revision total knee arthroplasty. The patients were distributed among two groups based on the type of metaphyseal fixator: sleeves (Group I, n=97 patients) and cones (Group II, n=37 patients). Surgical outcomes were assessed upon discharge from the hospital (after the hospital stay of 7-12 days), as well as after 6, 12 and 24 months after surgery. The survival rate of endoprostheses was analyzed using the Kaplan–Meier method. A revision with total replacement of the endoprosthesis or its components was considered a critical event. Results. The analysis of the survival rate of endoprostheses in the form of various metaphyseal fixators showed that the groups of sleeves and cones did not differ statistically significantly as suggested by the logrank test (Mantel–Cox): p=0.108. Conclusion. The midterm follow-up revealed no difference in clinical, functional, or radiological outcomes of revision total knee arthroplasty performed for types 2A, 2B, and 3 of bone defect replacement (sensu Anderson Orthopaedic Research Institute classification) using trabecular metal metaphyseal cones vs. sleeves.

Recent Trends and Hotspots in Knee Arthroplasty: A Bibliometric Analysis and Visualization Study of the Last Five-Year Publications.

Bibliometric analysis is one of the most prevalent methods for analyzing and predicting the research trends of particular subjects. Through a bibliometric analysis, this study sought to look into and depict the hotspots and research trends in knee arthroplasty research over the previous five years. The Web of Science Core Collection database was used to find research articles on knee arthroplasty published between 2018 and 2022. The VOS viewer, Cite Space, and Bibliometrix were used to carry out the bibliometric study and network visualization. During the previous five years, 7,422 included knee arthroplasty publications were cited 57,087 times. The United States and the Journal of Arthroplasty were the top countries and journals regarding the number of articles. The top 10 global high-impact documents were determined using the citation ranking and citation burst. The most frequently referenced article revealed that the epidemiological characteristics of knee arthroplasty, perioperative care in knee arthroplasty, prosthetic joint infections, and opioid medications were the hot topics in knee arthroplasty research. Keyword burst analysis showed that the research trends in knee arthroplasty through 2022 were racial disparity, limb alignment, tibial slope, and meniscectomy. The analysis of the subject areas revealed the close connections and relationships between different subject areas, as demonstrated by the figures. The knee arthroplasty research community is highly productive and centralized. Recent hotspots in knee arthroplasty research were unicompartmental knee arthroplasty, periprosthetic joint infection, kinematic alignment, outpatient total knee arthroplasty (TKA), bariatric surgery, payment model, tranexamic acid, Robotic-Assisted TKA, patient-reported outcome measures, metaphyseal cone, opioid use, and patient-specific instrumentation. Research trends in knee arthroplasty research were racial disparity, limb alignment, tibial slope, and meniscectomy.

Two-Year Survivorship and Outcomes of a Three-Dimensional Printed Metaphyseal Cone in the Setting of Revision Total Knee Arthroplasty.

Poor metaphyseal fixation secondary to bone loss in revision total knee arthroplasty (TKA) continues to be challenging. One technique to increase implant stability is the use of novel three-dimensional (3D) printed titanium metaphyseal cones with adjunctive stems for added fixation. However, the survival of these novel constructs is poorly understood. Therefore, we sought to examine 3D-printed titanium metaphyseal cone components in revision TKA for aseptic as well as septic reasons and aimed to evaluate: (1) revision-free survivorships; (2) patient-reported outcomes measures (PROMs); (3) postoperative medical complications; and (4) radiographic outcomes. A consecutive series of 62 patients who underwent revision TKA with use of a titanium metaphyseal cone at a single institution between September 1, 2015 and May 31, 2021 were examined. The patients had a minimum follow-up period of 2 years (mean, 40 months, range, 24-72 months). PROMS included Knee Injury and Osteoarthritis Outcome Score Joint Replacement (KOOS-JR) scores at baseline and last clinical follow-up. Overall, when excluding infections, the combined implant survivorship was 96% (52 out of 54), while it was 95% (35 out of 57) for aseptic revisions and 100% (17 out of 17) for septic revisions. Reasons for revisions within the aseptic revision cohort included loosening (5%) as well as periprosthetic joint infections (PJIs) (7.5%). All failures following an index septic revision were due to PJI. Mean KOOS scores at baseline as well as at final follow-up was 43 points (range, 16-80) and 70 points (range, 34-100), respectively. None of the patients had medical complications. Other than the loosening reported (only femoral component), of the surviving patients no patients had evidence of progressive radiolucencies. The use of titanium cones in revision TKA provides good revision-free survivorship at 2 years. Further research is warranted on the longer-term survivorship of 3D-printed titanium cones. The current study has found that 3D-printed titanium cones can be incorporated as part of the revision knee surgeon's armamentarium.

Novel metaphyseal porous titanium cones allow favorable outcomes in revision total knee arthroplasty.

Loosening and migration are common modes of aseptic failure following complex revision total knee arthroplasty (rTKA). Metaphyseal cones allow surgeons to negotiate the loss of femoral and tibial bone stock while obtaining stable bony fixation. This study examines the mid-term functional and radiographic outcomes in patients undergoing rTKA utilizing a novel metaphyseal cone system with stems of variable length and fixation methods. This two-center retrospective study examined all patients who underwent rTKA with a novel porous, titanium tibial or femoral cone in combination with a stem of variable length and fixation who had a minimum follow-up of 2-years. Outcome analysis was separated into tibial and femoral cones as well as the stem fixation method (hybrid vs. fully cemented). Overall, 123 patients who received 156 cone implants were included (74 [60.2%] tibial only, 16 [13.0%] femoral only, and 33 [26.8%] simultaneous tibial and femoral) with a mean follow-up of 2.76 ± 0.66years. At 2-years of follow-up the total cohort demonstrated 94.3% freedom from all-cause re-revisions, 97.6% freedom from aseptic re-revisions, and 99.4% of radiographic cone osteointegration. All-cause revision rates did not differ between stem fixation techniques in both the tibial and femoral cone groups. The use of a novel porous titanium femoral and tibial metaphyseal cones combined with stems in patients with moderate to severe bone defects undergoing complex revision total knee arthroplasty confers excellent results independent of stem fixation technique. IV, case series.

Metaphyseal fixation in revision knee arthroplasty: a systematic review of the literature and meta-analysis of mid-long-term outcomes of metaphyseal sleeves and cones.

Metaphyseal augmentation has in recent years formed a key strategy in management of bone loss in revision knee arthroplasty. There are studies reporting excellent short-term results, however long- term data is lacking. There is also a paucity of studies comparing the most frequently utilised augments, metaphyseal sleeves, and cones. We conducted a systematic review and meta-analysis to evaluate and compare the mid to long term outcomes of metaphyseal cones and sleeves. We conducted systematic search of 4 databases (Medline, Embase, CINALH and PubMed). Seventeen studies were found to be eligible for inclusion of which ten investigated metaphyseal sleeves and the remaining seven investigated cones. Mean follow up across all studies was 6.2 years. The total number of patients included in the studies was 1319 and the number of knees operated on was 1431. We noted a higher revision rate of metaphyseal cones when compared to sleeves 10.85% vs 6.31 (p=0.007). Reoperation rates were also higher in cones compared to sleeves, 13.78% vs 3.68% (p<0.001). Prosthetic joint infection was the most common reason for revision. The difference in conversion rates, based on augment location was statistically significant p=0.019. When undertaking further sub-analysis; there was no statistically significant difference when comparing revision rates of; tibial vs femoral augments p=0.108, tibial vs tibial & femur p=0.54 but a difference was seen between femoral vs tibial & femoral augments p=0.007. Based on our data, metaphyseal sleeves demonstrate significantly lower revision rates compared to metaphyseal cones. However overall, both demonstrate reliable mid to long-term outcomes.

Radiographic and clinical analysis of a Porous-coated metaphyseal cone for revision total Knee arthroplasty

BackgroundThe aim of this study was to evaluate the radiographic and clinical outcomes of a recently introduced metaphyseal cone system for revision TKA. Methods73 revision TKAs in 72 patients were retrospectively reviewed. All patients had a minimum of 2-year clinical follow-up (mean 34.1 months; range 24.0 to 50.3 months). 114 Metaphyseal cones (64 tibial and 50 femoral) of a single manufacturer were implanted. The most common indications for revision were aseptic loosening (56.9%), second stage reimplantation for periprosthetic joint infection (PJI; 26.4%), and instability (12.5%). All femoral and tibial stems were press-fit cementless stems. ResultsTen of 72 patients underwent re-revision: six for infection (8.3%), two for instability (2.8%), one (1.4%) for patellar tendon rupture and one (1.4%) for femoral component loosening (a cone was not utilized at index revision). Two patients had loose cones (one with an isolated tibial cone and one with both femoral and tibial cones) associated with loose implants but declined re-revision. Aseptic survivorship of our patient cohort free from any re-revision surgery was 95.9% at 2 years (95% CI 87.4–98.7%) and 96.5% of cones demonstrated radiographic evidence of osseointegration. At 2-years, the Knee Society Score (KSS) improved from a mean of 17.2 points preoperatively to 57.8 points (p <.0001). ConclusionsPorous-coated metaphyseal cones from this manufacturer demonstrate excellent aseptic survivorship and radiographic evidence of osseointegration similar to prior designs when used with cementless stems.

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.

Survivorship of Metaphyseal Cones and Sleeves in Revision Total Knee Arthroplasty.

Bone loss remains an anticipated challenge in revision total knee arthroplasty (rTKA). Recent efforts to enhance rTKA fixation and stability have focused on metaphyseal implants, namely cones and sleeves. We sought to compare cone and sleeve implant survivorship in rTKA. One hundred eighty patients who underwent rTKA with metaphyseal implants from 2005 to 2018 were retrospectively reviewed. A total of 83 cones (22 femoral, 62 tibial) and 121 sleeves (58 femoral, 63 tibial) were identified. The mean age at the time of surgery was 72 years (range 43-97). Intraoperative Anderson Orthopaedic Research Institute bone loss classifications included the following: type 2A (25), type 2B (98), and type 3 (81). Mean follow-up was 41 months. Revision-free survival for cones was 91.3% vs 92.2% for sleeves (P= .29). Twelve knees (4 cones, 8 sleeves) underwent irrigation, debridement, and polyethylene exchange with metaphyseal implant retention for acute postoperative periprosthetic joint infection (PJI). Development of chronic PJI warranted removal of 7 cones (8.4%), 6 of which were initially placed as part of a 2-stage revision TKA. Eight sleeves (6.6%) were removed for PJI, with all initially placed during a second stage reimplantation. In the absence of infection, survival was 100% and 99.1% for cones and sleeves, respectively. One sleeve was revised for periprosthetic fracture. Metaphyseal cones and sleeves offer equally durable survivorship in revision TKA. PJI was the most common mode of implant failure in this series. Importantly, no cases of cone or sleeve aseptic loosening were observed.

Early Infection After Aseptic Revision Knee Arthroplasty: Prevalence and Predisposing Risk Factors.

Although patient factors have been associated with prosthetic joint infection (PJI) after primary total knee arthroplasty, there are insufficient data on the relationship of patient and technical factors with early PJI after aseptic revision. This is a retrospective study of 157 aseptic revisions performed by 2 surgeons at 1 academic center. A negative intraoperative culture during revision surgery was required for inclusion. Mean follow-up time was 3.8 years (standard deviation 2.8). PJI was defined by positive aspiration or draining wound, and an additional operation within 1 year of aseptic revision. Patient demographics, medical comorbidities, and technical factors were reviewed. Data points were evaluated with univariate and adjusted multivariate regression analyses. The prevalence of PJI after aseptic revision was 9% (14/157). The most common organism was Staphylococcus aureus. Initial treatment included debridement and liner exchange (11) and antibiotic spacer (3). Two patients ultimately had an above-knee amputation. Univariate analysis showed a significant difference in preoperative anemia (P < .01), transfusion (P < .01), and diabetes (P= .05) between cohorts. There was no association among the length of surgery, use of a metaphyseal cone, or the number of components revised and PJI. Adjusted logistic regression demonstrated that preoperative anemia (P < .01) was a significant risk factor for PJI. The prevalence of early PJI was similar to other studies in the literature. Anemia was an independent predictor of PJI, while technical factors did not have an association. Medical optimization of patients should be considered prior to revision surgery.

Reconstruction for Massive Proximal Tibial Bone Defects Using Patient-Customized Three-Dimensional-Printed Metaphyseal Cones in Revision Total Knee Arthroplasty.

ObjectiveTo review the clinical outcomes of revision total knee arthroplasty (RTKA) with massive proximal tibial bone defects using patient‐customized three‐dimensional (3D) printed highly porous metaphyseal cones.MethodsA retrospective study of all patients at our institution who underwent RTKA with the Anderson Orthopaedic Research Institute type III tibial defects using patient‐customized 3D‐printed highly porous metaphyseal cones was performed from 2016 to 2018. Seven patients were enrolled in this study. General results (age, sex, and body mass index); intraoperative results (interface compatibility and stability, and operating time); and perioperative complications (total blood loss, blood transfusion rate, and deep venous thrombosis) were recorded and analyzed. Clinical improvement and functional evaluation (survivorship of implant, improvement of Hospital for Special Surgery Score and McMaster Universities Osteoarthritis Index, and improvement of range of motion [ROM]), and radiographic improvement and implant evaluation (progressive radiolucent lines or radiographic loosening, and mechanical alignment) were evaluated at 2 weeks, 6 weeks, 3 months, 6 months, 1 year, 2 years, and then annually, postoperatively.ResultsThe mean age at diagnosis was 68 (61–77) years. The mean follow‐up was 25.3 (19–36) months. At the latest follow‐up, no aseptic loosening, prosthetic joint infection, or other complications were noted. The mean Hospital for Special Surgery Score increased from 49 (39–63) to 78 (70–83) (P < 0.01), whereas the mean Western Ontario and McMaster Universities Osteoarthritis Index increased from 59 (46–73) to 26 (12–38) (P < 0.01). All patients achieved improved postoperative ROM with the mean flexion angle increasing from 66° (30°–80°) to 93° (80°–100°), and improved mechanical alignment with all hip–knee–ankle (HKA) angles within ±3°.ConclusionsThe patient‐customized 3D‐printed metaphyseal cone is useful technique for reconstructing massive proximal tibial bone defects, with encouraging clinical and radiological outcomes in RTKA.

Tibial Tubercle Screw Fixation on Custom Metaphyseal Cone: Surgical Tip in Severe Metaphyseal Tibia Bone Loss.

Tibial tubercle osteotomy (TTO) facilitates exposure in knee arthroplasty revision. However, it comes with complications, especially if it invades the intramedullary canal. Most revisions are characterized by compromised femur and/or tibia bone stock, and the use of metaphyseal cones or sleeves for implant fixation has become increasingly frequent. Several methods of fixation of the tibial tubercle have been proposed, such as screw fixation, cerclage wiring, and suture repair. Despite screws providing the strongest fixation for TTO, their placement around a tibial intramedullary stem or a metaphyseal tibial cone may be difficult. We described the use of a custom-made metaphyseal tibial cone with holes in its anterior surface that allow the surgeon to achieve accurate TTO fixation by screws.

The biomechanics of metaphyseal cone augmentation in revision knee replacement

The demand for revision knee replacement (RKR) has increased dramatically with rising patient life expectancy and younger recipients for primary TKR. However, significant challenges to RKR arise from osseous defects, reduced bone quality, potential bone volume loss from implant removal and the need to achieve implant stability. This study utilizes the outcomes of an ongoing RKR clinical trial using porous metaphyseal cones 3D-printed of titanium, to investigate 1) bone mineral density (BMD) changes in three fixation zones (epiphysis, metaphysis, and diaphysis) over a year and 2) the biomechanical effects of the cones at 6 months post-surgery. It combines dual-energy x-ray absorptiometry (DXA), computed tomography (CT) with patient-specific based finite element (FE) modelling. Bone loss (−0.086 ± 0.05 g/cm2) was found in most patients over the first year. The biomechanical assessment considered four different loading scenarios from standing, walking on a flat surface, and walking downstairs, to a simulated impact of the knee. The patient-specific FE models showed that the cones marginally improved the strain distribution in the bone and shared the induced load but played a limited role in reducing the risks of bone fracture or cement debonding. This technique of obtaining real live data from a randomized clinical trial and inserting it into an in-silico FE model is unique and innovative in RKR research. The tibia RKR biomechanics examined open up further possibilities, allowing the in-silico testing of prototypes and implant combinations without putting patients at risk as per the recommended IDEAL framework standards. This process with further improvements could allow rapid innovation, optimization of implant design, and improve surgical planning.

Intermediate-Term Survivorship of Metaphyseal Cones and Sleeves in Revision Total Knee Arthroplasty

BackgroundBoth cones or sleeves have been developed to address metaphyseal bone loss in revision total knee arthroplasty (TKA), but few studies have directly compared the outcomes. The purpose of this study was to compare the survivorship and aseptic revision rates between metaphyseal cones and sleeves at intermediate follow-up. MethodsWe reviewed a consecutive series of 1,172 revision TKA patients between 2009 and 2018 with a minimum two-year follow-up on all patients. We compared demographics, surgical indication, stem fixation, constraint, rates of rerevision, and Short-Form-12 scores between patients with cones and sleeves. A multivariate analysis was performed to identify the effect of cones and sleeves on aseptic rerevision. Kaplan-Meier curves were generated to compare aseptic survivorship of cones and sleeves. ResultsThere were 194 tibial cones (17%), 107 tibial sleeves (9%), 31 femoral cones (3%), and 135 femoral sleeves (12%) with a mean follow-up of 6.5 years (range: 2-12 years). There was no difference in demographics, indication, stem fixation, or constraint (P > .05). Although overall aseptic failure rates may be lower for tibial sleeves, there were no significant differences in survivorship over a one-year, two-year, and five-year follow-up when both tibial and femoral sleeves were directly compared to cones. ConclusionBoth tibial and femoral sleeves and cones perform well at an intermediate-term follow-up. Further investigation of these two are required to better understand their survivorship relative to each other.

The use of tantalum cones and diaphyseal-engaging stems in tibial component revision: a consecutive series

IntroductionRevision knee arthroplasty presents a number of challenges, including management of bone loss. The goal in managing moderate to large bone defects is fixation that is sufficient enough to allow early weight-bearing. The purpose of this study was to describe the surgical technique and clinical and radiographic outcomes of patients treated with porous tantalum metaphyseal cones in combination with long uncemented diaphyseal-engaging stems to manage tibial bone loss in revision total knee arthroplasty (TKA).Materials and methodsThirty-six aseptic revision TKAs were performed at our institution between 2016 and 2019 by two senior authors. A single trabecular metal tantalum cone combined with a long (100 or 155 mm) press fit, diaphyseal-engaging stem was used in all cases to reconstruct metaphyseal bone defects and to augment tibial fixation. Cemented stems were excluded. The tibiofemoral angle was measured along the tibial and femoral shaft axes on the weight-bearing anteroposterior radiograph at final follow-up (range 15–56 months). All clinical and surgical complications, reoperations, and revisions of any component were recorded. Survivorship free of revision was evaluated at the time of the latest follow-up.ResultsThe mean Knee Society Score (KSS) and Knee Society Function Score (KSS-F) improved significantly from 29.7 points preoperatively (range 11–54 points) to 86 points (range 43–99 points) and from 20.4 points preoperatively (range 0–55 points) to 72.3 points (range 30–90 points) (p < 0.05), respectively. Eleven tibial constructs (30.5%) had incomplete, nonprogressive radiolucent lines (≤ 2 mm). All tibial cones demonstrated osteointegration. One patient underwent a full revision for periprosthetic joint infection, and survivorship free of any component revision was 91.7% at final follow-up.ConclusionsHybrid fixation with uncemented diaphyseal-engaging stems and porous tantalum metaphyseal cones resulted in radiographic lack of osteolysis, good clinical outcomes, and survivorship of 91.7% at a median follow-up of 33 months when considering all-cause revision as the endpoint.

High survival rate at mid-term follow up of porous tantalum cones for bone defects in revision total knee replacement: A 3–11 years follow up report

BackgroundLarge metaphyseal bone losses are commonly encountered in revision total knee arthroplasty (rTKA). Anderson Orthopaedic Research Institute (AORI) type 2 and 3 defects generally require some metaphyseal fixation or augmentation.This study evaluates the midterm results of Porous Tantalum Trabecular Metal™ (TM) cones in revision TKA addressing severe bone loss. MethodsPatients who underwent revision TKA using metaphyseal cones and a varus–valgus constrained (VVC) implant from January 2010 to January 2018 at our institution were identified from a prospective research database. Pre-operative patient characteristics and operative data were reviewed. Postoperative outcomes were compared with pre-operative values. Primary study aims were to evaluate outcomes, including complications and re-operations, radiographic assessment of cones osteointegration, and survivorship. ResultsA total of 101 knees (101 patients) underwent revision TKA with 139 metaphyseal cones (80 tibial, 59 femoral). AORI defect classification was assessed intraoperatively. All patients were available for a minimum of 2 years of clinical and radiographic follow up. Mean follow up was 7.5 years (range 3–11 years).All patients showed significant improvement of clinical outcomes. Fifteen knees required re-operation and nine required revision of the implants, most commonly for recurrent infection (six of nine revisions) with cones removal.Kaplan–Meier survival analysis show a survival rate of 93.9% at 2 years and a survival rate of 90.2% at 5 and 11 years. ConclusionsThis large series illustrates the utility of porous metaphyseal cones in revision TKA with promising clinical and radiographic results and a high survival rate at mid-term follow up.

Use of Cementless Metaphyseal Fixation in Revision Total Knee Arthroplasty in the United States

Fixation options for revision total knee arthroplasty (rTKA) have expanded and now include cementless metaphyseal fixation. The utilization rates of these implants in the United States are not well known. The purpose of this study was to analyze trends in cementless metaphyseal fixation for rTKA within the American Joint Replacement Registry (AJRR). The AJRR was queried for the years 2015-2019 to identify all rTKA with implant data. Trends in the use of cementless sleeves, metaphyseal cones, and any cementless metaphyseal fixation (sleeves+ cones) were examined over the study period using logistic regression analysis. Twenty thousand two hundred and eighty rTKA were analyzed. Cementless metaphyseal fixation was used in 16% of rTKA and significantly increased over the study period (14% to 19%, P < .0001). Cementless metaphyseal fixation was more frequently utilized during revision for aseptic loosening than other diagnoses (OR 1.014, 95% CI 1.001-1.027). Cementless sleeve utilization decreased over time (11% to 9%, P= .004), driven by decreased use on the femur (4% to 2%, P < .0001). The use of cones increased significantly over time (3% to 9%, P < .0001), driven by increased use on the tibia (2% to 9%, P < .0001). Cones were 22 times more likely to be utilized on the tibia relative to the femur (P < .0001) and were more likely to be used in revisions for infection (OR 1.103, 95% CI 1.089-1.117) and aseptic loosening (OR 1.764, 95% CI 1.728-1.800). Cementless metaphyseal fixation has grown in popularity yet, still comprised only 16% of rTKA over a 5-year period. Most of the increase was due to the utilization of tibial metaphyseal cones.

Clinical and Radiographic Outcomes of Novel 3D-Printed Highly Porous Knee Cone Design.

Metaphyseal bone defects seen at revision total knee replacement (TKA) have traditionally been treated with bone graft or cement. Recently, metal augments have surfaced as viable alternatives to conventional methods previously used in these patients. Newer 3D-printed metal cones offer better biological fixation as a means of improving construct stability. This study aimed to determine clinical and radiographic outcomes of the novel 3D-printed titanium cone augments for femoral and tibial metaphyseal bone defects. A retrospective review was undertaken of 72 patients who underwent revision TKA with metaphyseal cones (Stryker) and stemmed implants from 2015-2017. Knee Injury and Osteoarthritis Outcome Scores (KOOS Jr) and VR/SF-12 scores were recorded. Knee Society radiographic scores were calculated at latest follow up to evaluate for radiolucency and biological fixation. Loosening noted on radiographs and reoperation for any reason were the endpoints to determine survivorship. A total of 68 patients with 78 cones (58 tibial, 20 femoral) met inclusion criteria. Mean follow up was 3.4 years (range 2-5.4 years). The average KOOS Jr score increased from 38 preoperatively to 66 at two years. The average VR/SF-12 PH score increased from 33 preoperatively to 37 at two years. The average VR/SF-12 MH score increased from 46 preoperatively to 54 at two years. Twelve percent of tibial implants and 10% of femoral implants with cones were found to have lucency in at least one radiographic zone. Overall survivorship at latest follow up was 93% with two patients requiring revision for infection, two revised following mechanical complications, and one patient who underwent polyethylene exchange after experiencing mechanical complications. When considering only aseptic loosening, survivorship was 100%. This 3D-printed titanium femoral and tibial cone augment system showed excellent survivorship, biological fixation, clinical outcomes, and radiographic outcomes in the setting of TKA. Further studies are needed for assessment of long-term survivorship.

Survivorship and Radiographic Evaluation of Metaphyseal Cones With Short Cemented Stems in Revision Total Knee Arthroplasty.

The purpose of this study is to evaluate the survivorship and radiographic outcomes of a single design of metaphyseal cone used in conjunction with short cemented stems. A retrospective analysis was conducted of revision total knee arthroplasty (rTKA) patients (June 2015 to December 2017) using porous titanium femoral or tibial cones in conjunction with short cemented stems (50-75 mm). Minimum follow-up was 2 years. Survivorship, complications, and a modified Knee Society Radiographic score were analyzed. Forty-nine rTKAs were included in the study (12 femoral cones, 48 tibial cones). Varus-valgus constraint was used in 28 (57%) and a hinged bearing was used in 3 (6%) of these constructs. The majority were index rTKAs of primary components (86%), performed for aseptic loosening (51%) and reimplantation following staged treatment for infection (37%). Median follow-up was 39 months (range 25-58). Using a modified Knee Society Radiographic score, all constructs were classified as stable. Postoperatively, 4 rTKAs were complicated by recurrent infection (8%), periprosthetic fracture 2 (4%), and superficial wound infection 1 (2%). Seven rTKAs (14%) required reoperation. The majority of reoperations (4 rTKAs) were debridement and irrigation with implant retention for infection. Metaphyseal cone constructs with short cemented stems demonstrated 100% survivorship free of revision for aseptic loosening without evidence of radiographic loosening in any case. Our results demonstrate excellent outcomes with the use of metaphyseal cones with short cemented stems at mid-term follow-up. This construct avoids the use of long-stem fixation with the associated extraction difficulty, end of stem pain, and potential for malposition at the joint line. IV, Case Series.

Zonal Fixation in Revision TKA: The Key Is Metaphyseal Fixation.

As the volume of primary total knee arthroplasties continues to rise, so will the volume of revision arthroplasties. Bone loss is commonly encountered in revision surgery and must be managed appropriately to optimize outcomes. The concept of zonal fixation highlights the importance of attaining secure fixation within each of the three major osseous zones: the epiphysis, the metaphysis, and the diaphysis. While each zone is important, the metaphysis carries particular significance. The development of new implants such as metaphyseal cones and sleeves has greatly expanded the orthopedic surgeon's armamentarium to allow for solid metaphyseal fixation in virtually every case.