The Use of Tantalum Metaphyseal Cones for the Management of Severe Bone Defects in Septic Knee Revision

Are Proud Tibial Cone Constructs an Effective Alternative to Those That are Fully Seated in Revision Total Knee Arthroplasty?

BACKGROUND

This study compared the clinical, radiographic, and patient-reported outcomes between patients treated with the traditional fully seated tibial cone construct and those with the novel proud tibial cone construct in revision total knee arthroplasty (rTKA).

METHODS

This was a retrospective study of 56 adult patients who had a minimum 2-year follow-up and underwent rTKA with either the fully seated (n = 18 knees) or proud (n = 42 knees) tibial cone construct between 2010 and 2020. The electronic medical record was reviewed for demographic, clinical, and radiographic data. Knee Injury and Osteoarthritis Outcome Scores (KOOS) were collected.

RESULTS

All patients had improved mechanical alignment postoperatively regardless of surgical technique. All patients showed good evidence of osseointegration without loss of fixation at the latest follow-up. There were no significant differences in the complication rate or re-revision rate between the groups. KOOS Function in Sport and Recreation (Sport/Rec) scores were significantly higher for patients treated with the fully seated construct (mean 57 [range, 20 to 95] versus 38 [range, 0 to 75], P = .04); however, no significant differences were present for the other KOOS subscales or KOOS Jr.

CONCLUSION

The proud tibial cone construct may be an effective alternative to the fully seated construct in the setting of severe bone loss in rTKA. The proud construct avoids a proximal tibial cut, and thus is a bone-preserving technique that provides good fixation, reduces operative time, prevents potential iatrogenic injuries, decreases the need for tibial augments, saves costs, and improves the ease of restoring joint height.

John N. Insall Award: Randomized Clinical Trial of Cementless Versus Cemented Tibial Components: Durable and Reliable at a Mean 10-Years Follow-Up

BACKGROUND

Cementless fixation is gaining popularity for primary total knee arthroplasties (TKAs). The prior 5-year results of our randomized clinical trial that included 3 different tibial designs found minimal differences. The purpose of the current study was to investigate the 10-year results in the same cohort.

METHODS

Between 2003 and 2006, 389 primary TKAs were randomized: traditional modular cemented tibia (135); hybrid (cemented baseplate with uncemented pegs) monoblock tibia (128); and cementless monoblock tibia (126). Implant survivorships, radiographs, and clinical outcomes were analyzed. Mean age at TKA was 68 years (range, 41 to 85), 46% were male, and mean body mass index was 32 (range, 21 to 59). The mean follow-up was 10 years.

RESULTS

The 10-year survivorship free of any revision was similar between the hybrid monoblock and cementless monoblock groups at 96%, but lower (89%) for the traditional modular cemented tibia (P = .05). The traditional modular cemented tibia group had significantly more revisions for aseptic tibial loosening than the other 2 groups (7 versus 0%) at 10 years (P = .003). The traditional modular cemented tibia group had significantly more nonprogressive radiolucent lines than the hybrid and cementless monoblock groups (24, 12, and 9%, respectively). Clinical outcomes were similar and excellent between all 3 groups.

CONCLUSION

Cementless and hybrid monoblock tibial components have excellent implant survivorship (96%) with no cases of aseptic tibial loosening to date. The traditional cemented modular tibial group had a 7% cumulative incidence of aseptic loosening at 10 years.

LEVEL OF EVIDENCE

Level I, Prospective Randomized Control Trial.

Current Advances and Applications of Tantalum Element in Infected Bone Defects

Infected bone defects (IBDs) cause significant economic and psychological burdens, posing a huge challenge to clinical orthopedic surgeons. Traditional approaches for managing IBDs possess inevitable shortcomings; therefore, it is necessary to develop new functionalized scaffolds. Tantalum (Ta) has been widely used in load-bearing orthopedic implants due to its good biocompatibility and corrosion resistance. However, undecorated Ta could only structurally repair common bone defects, which failed to meet the clinical needs of bacteriostasis for IBDs. Researchers have made great efforts to functionalize Ta scaffolds to enhance their antibacterial activity through various methods, including surface coating, alloying, and micro- and nanostructure modifications. Additionally, several studies have successfully utilized Ta to modify orthopedic scaffolds for enhanced antibacterial function. These studies remarkably extended the application range of Ta. Therefore, this review systematically outlines the advances in the fundamental and clinical application of Ta in the treatment of IBDs, focusing on the antibacterial properties of Ta, its functionalization for bacteriostasis, and its applications in the modification of orthopedic scaffolds. This study provides researchers with an overview of the application of Ta in the treatment of IBDs.

Tantalum Cones for Severe Bone Defects in Revision Knee Arthroplasty: A Minimum 10-Year Follow-Up

BACKGROUND

Two-to 6-year results of reconstruction of severe bone defects in revision total knee arthroplasty (TKA) with highly porous tantalum cones have been encouraging, but 10-year follow-up is lacking. The purpose of this study was to determine the minimum 10-year results of tantalum cones in revision TKA.

METHODS

From 2005 to 2010, 30 consecutive patients (30 knees) underwent revision TKA with the use of cones. All patients were followed clinically and radiographically for a minimum of 10 years. A total of 42 cones (25 tibial and 17 femoral) were used to reconstruct massive bone defects classified as Anderson Orthopaedic Research Institute Types 2A (10), 2B (12), and 3 (19). The mean age of the patients was 73 years (range, 55 to 84) at the time of revision. The indication for the revision included aseptic loosening (15 patients) and second-stage reimplantation for deep infection (15 patients). Six patients were lost to follow-up.

RESULTS

In total, 6 cones had to be revised. Minimum 10-year cone survivorship for any reason was 81% (25 of 31 cones). With cone revision for aseptic loosening as the end point, survivorship was 96% (30 of 31). No evidence of loosening or migration of any implant was noted on the most recent radiographs.

CONCLUSION

Metaphyseal fixation with tantalum cones in revision TKA demonstrated excellent survivorship and fixation at a minimum follow-up of 10 years. This type of metaphyseal reconstruction can be a durable option for revision TKA in patients who have massive bone defects.

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

Backgrounds

There 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.

Methods

In 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.

Results

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 94.4% 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.

Conclusion

Tibial 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.

The Cost-Effectiveness of Tibial Metaphyseal Cones in Revision Total Knee Arthroplasty

BACKGROUND

The purpose of this study is to evaluate the cost-effectiveness of tibial cones in revision total knee arthroplasty.

METHODS

A Markov model was used for cost-effectiveness analysis. The average cone price was obtained from Orthopedic Network News. The average cone aseptic loosening rate was determined by literature review. Hospitalization costs and baseline re-revision rates were calculated using the PearlDiver Database.

RESULTS

The maximum cost-effective cone price varied from $3514 at age 40 to $648 at age 90, compared to the current average selling price of $4201. Cones became cost-effective with baseline aseptic loosening rates of 0.89% annually at age 40 to 4.38% annually at age 90, compared to the current average baseline loosening rate of 0.76% annually.

CONCLUSION

For the average patient, tibial cones are not cost-effective, but may become so at lower prices, in younger patients, or in patients at substantially increased risk of aseptic loosening.

Comparison of Different Strategies in Revision Arthroplasty of the Knee with Severe Bone Loss: A Systematic Review and Meta-Analysis of Clinical Outcomes

BACKGROUND

In revision total knee arthroplasty large bone lesions can jeopardize correct implant orientation and fixation. Different strategies have been proposed to tackle this issue. The purpose of this review and meta-analysis is to evaluate the midterm clinical and survivorship results of porous cones and porous-coated sleeves compared to morselized and structural grafts.

METHODS

We performed a systematic review of the literature on the different strategies targeting moderate to large metaphyseal bone defects. The literature was evaluated for methodological quality. We analyzed results on survivorship using logistic regression correcting for follow-up time and number of knees. We compared these results using forest plots for early and midterm follow-up. Clinical outcome was evaluated by comparing standardized mean difference of patient-related outcome measures.

RESULTS

A total of 77 articles analyzing 4,391 knees were included. The logistic regression curve showed a nonsignificant odds ratio (OR) at 10 years of 0.91 (95% confidence interval [CI] 0.699-1.192, P = .49) for failure comparing all porous implants with all grafting procedures. The available clinical reports show a bigger standardized mean difference increase for tantalum cones (OR 3.04, 95% CI 1.71-4.37) than for porous sleeves (OR 1.72, 95% CI 0.88-2.57).

CONCLUSION

Our analysis shows that the size and quality of the literature on metaphyseal bone defects is progressively improving. Porous implants are effective in tackling metaphyseal bone defects showing good survivorship outcome at midterm follow-up. In younger patients with less constrained prosthetic implants, surgeons might still consider the use of grafts without risking worse outcomes.

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

Objective

To 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.

Methods

A 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.

Results

The 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°.

Conclusions

The patient‐customized 3D‐printed metaphyseal cone is useful technique for reconstructing massive proximal tibial bone defects, with encouraging clinical and radiological outcomes in RTKA.

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

BACKGROUND

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).

METHODS

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.

RESULTS

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).

CONCLUSION

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.

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

BACKGROUND

Large 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.

METHODS

Patients 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.

RESULTS

A 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.

CONCLUSIONS

This 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.

Cones and sleeves present good survival and clinical outcome in revision total knee arthroplasty: a meta-analysis

PURPOSE

The fixation of revision total knee arthroplasties (rTKA) tends to be difficult, leading to a reduction in implant survival. One option for achieving a more stable anchorage is to use metaphyseal cones and sleeves. The objective of the present paper is to provide a current comparative meta-analysis on survival and clinical results of cones vs. sleeves, with a differentiation between the short- and long-term outcome.

METHODS

A search of the literature was conducted systematically to include original papers from 2010 to June 2021. The following parameters were taken into account: revision for aseptic loosening, revision for any reason, periprosthetic joint infections (PJI), KSS as well as KSFS. Studies with a mean follow-up of at least 60 months were defined to be long-term follow-up studies (LT). All other studies were included in the short-term (ST) study analysis. A pooled incidence was used as a summary statistic using a random intercept logistic regression model.

RESULTS

The present meta-analysis included 43 publications with 3008 rTKA. Of these, 23 publications with 1911 cases were allocated to the sleeve group (SG) and 20 papers with 1097 cases to the cone group (CG). CG showed overall numerically higher complication rates in short- and long-term follow-up, compared with SG. Aseptic loosening occurred at a rate of 0.4% in SG (LT) and 4.1% in CG (LT) (p = 0.09). Periprosthetic joint infection (PJI) was more frequent in the cone group (7% in ST and 11.7% in LT) than in the sleeve group (3.4% in ST and 4.9% in LT, p = 0.02 both). The total revision rate was 5.5% in SG (LT) and 14.4% in CG (LT) (p = 0.12). The clinical scores were also comparable between the two groups. Hinged prothesis were used more frequent in the cone group (ST p < 0.001; LT p = 0.10), whereas CC type protheses were used more frequently in the sleeve group (ST p < 0.001; LT p < 0.11).

CONCLUSIONS

This meta-analysis takes into account the longest follow-up periods covered to date. Both cones and sleeves represent a reliable fixation method in the case of severe bone loss in rTKA, although the higher rate of PJI after cone fixation remains a source of concern. A metaphyseal fixation of hinged implants should be taken into account.

LEVEL OF EVIDENCE

II (meta-analysis).

Two-stage revision for periprosthetic joint infection in unicompartmental knee arthroplasty: clinical and radiological results

INTRODUCTION

Unicompartmental knee arthroplasty (UKA) has an infection rate of 0.1-0.8%. Despite the wide amount of literature about septic total knee arthroplasty management, few data are available for UKA infection treatment. The aim is to present the clinical and radiological outcomes along with complication rates of a series of septic UKA treated with two-stage exchange.

METHODS

We retrospectively reviewed 16 patient treated with staged UKA revision for infection between June 2015 and September 2019 in a single bone infection unit. The main demographic and surgical data were recorded. Clinical scores (VAS, KSS, OKS, postoperative ROM), radiological parameters (osseointegration, loosening and radiolucencies) and complications were reported. The mean follow-up was 33.5 ± 6.9 months.

RESULTS

Mean age at surgery was 68.5 ± 9.1. All but two were medial UKA. The mean number of previous surgeries was 2.9 ± 1.9. The mean ROM, VAS, KSS and OKS of the entire population improved significantly (p < 0.01). Radiological analysis did not show any migration or implant loosening. Ten constrained condylar and six posterior stabilized prosthesis were finally implanted. One intraoperative pathogen isolation was recorded and managed with suppressive therapy and good final outcome. The implant survivorship free from infection was 100% at the final follow-up. The overall survival rate for any reason of revision was 100% CONCLUSION: According to our results, staged revision represents a reliable ad effective option in delayed and late UKA infections. This technique provides optimal clinical and radiological results with acceptable complication rates. To the best of our knowledge, this represent the widest case series on infected UKA managed with two-stage exchange.

Two-stage arthroplasty for septic arthritis of the hip and knee: A systematic review on infection control and clinical functional outcomes

INTRODUCTION

Septic arthritis of the native hip and knee joint poses particular challenges to orthopedic surgeons. Patients often suffer from several comorbidities, and it could be challenging to find a balance between infection control and adequate function. Two-stage arthroplasty has been addressed as a reliable solution, however the literature on the topic is composed of case series with small sample size. This systematic review aimed to analyze data on infection control and clinical functional outcomes of patients who underwent two-stage arthroplasty for septic arthritis of the hip and knee.

METHODS

An electronic search of studies published from January 1st, 2000, to June 1st, 2021, was conducted using eight different databases. Following the Cochrane Handbook of Systematic Reviews of Interventions and Preferred Reporting Items for Systematic Revies and Meta-analysis two authors reviewed the available literature and reference lists to identify papers eligible for inclusion.

RESULTS

A total of 21 studies were included, involving 435 procedures. The mean age was 57.3 ± 6.2 (45.8-71.8) years. The mean follow-up was 53.7 ± 18.6 (12-86.7) months. The mean infection eradication was 93.3 ± 6.4%. Mean Harris Hip Score improved from 32.1 ± 10.6 (11.5-42.9) to 87.5 ± 5.7 (80.6-97.8). Mean Knee Society Score improved from 42.9 ± 7.6 (35.9-58.0) to 86.1 ± 5.4 (80.1-96.0).

CONCLUSIONS

Two-stage arthroplasty for hip and knee septic arthritis provided high infection control rate and excellent function. Further high-quality studies should be oriented on providing a validated algorithm for diagnosis and treatment of this condition.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III and IV studies.

[Bone defect management in revision knee arthroplasty]

BACKGROUND

In 2019, 124,677 primary total knee arthroplasties and 14,462 revision TKA were performed in Germany. This corresponds to a percentage of 11.6%. According to the EPRD, the probability of further revision surgery after the first exchange operation is around 15%.

REASONS

The most common reason for revision surgery is still aseptic loosening with 23.9%. One possible cause could be the difficult fixation of revision total knee arthroplasty. If the bone quality is insufficient, cement-free or cemented diaphyseal anchoring of the prosthesis is often not sufficient to ensure adequate fixation. As a rule, defect management and fixation of the implant are based on the defect situation and the quality of the bone. Therefore, revision total knee arthroplasties based on the fixation principle of Jones et al. should be sufficiently fixed in at least 2 zones.

TECHNIQUES

There are various techniques for stable anchoring of revision implants. In addition to cemented or cementless stem anchoring, bone allografts, wedges and blocks and, in recent years, cones and sleeves have become increasingly popular. In the present work, the various options for a stable anchoring of revision implants are presented and evaluated. In addition, the clinical and radiological outcome of cones vs. sleeves in bone defect management in revision knee arthroplasty will be compared.

Mid-term results of tibial cones : reasonable survivorship but increased failure in those with significant bone loss and prior infection

AIMS

Tibial cones are often utilized in revision total knee arthroplasty (TKA) with metaphyseal defects. Because there are few studies evaluating mid-term outcomes with a sufficient cohort, the purpose of this study was to evaluate tibial cone survival and complications in revision TKAs with tibial cones at minimum follow-up of five years.

METHODS

A retrospective review was completed from September 2006 to March 2015, evaluating 67 revision TKAs (64 patients) that received one specific porous tibial cone during revision TKA. The final cohort was composed of 62 knees (59 patients) with five years of clinical follow-up or reoperation. The mean clinical follow-up of the TKAs with minimum five-year clinical follow-up was 7.6 years (5.0 to 13.3). Survivorship analysis was performed with the endpoints of tibial cone revision for aseptic loosening, tibial cone revision for any reason, and reoperation. We also evaluated periprosthetic joint infection (PJI), risk factors for failure, and performed a radiological review.

RESULTS

The rate of cone revision for aseptic loosening was 6.5%, with an eight-year survival of 95%. Significant bone loss (Anderson Orthopaedic Research Institute grade 3) was associated with cone revision for aseptic loosening (p = 0.002). The rate of cone revision for any reason was 17.7%, with an eight-year survival of 84%. Sixteen percent of knees developed PJI following revision. A pre-revision diagnosis of reimplantation as part of a two-stage exchange protocol for infection was associated with both PJI (p < 0.001) and tibial cone revision (p = 0.001).

CONCLUSION

Mid-term results of tibial cones showed a survivorship free of cone revision for aseptic loosening of 95%. Patients with significant bone loss were more likely to have re-revision for tibial cone failure. Infection was common, and patients receiving cones at reimplantation were more likely to develop PJI and undergo cone revision. Cite this article: Bone Joint J 2021;103-B(6 Supple A):158-164.

Preliminary clinical results of coated porous tibia cones in septic and aseptic revision knee arthroplasty

PURPOSE

To analyze the first results of calcium-phosphate-coated porous tibia cones.

METHODS

Patients treated with TrabecuLink^®-CaP Cones were retrospectively recruited from January 2016 to December 2017. These custom-made cones were produced using titanium alloy Ti-6Al-4 V (Tilastan^®) and using additive manufacturing with a special calcium-phosphate coating (HX^®-coating). Clinical outcome was evaluated using Oxford Knee Score. For radiological evaluation of the implants, patients sent us outpatient taken radiographs. A minimum follow-up of one year was required. Lastly, we analyzed postoperative complications and revision rates.

RESULTS

52 patients with revision knee arthroplasty (RKA) were recruited for final analysis, of whom, we had 17 septic RKAs (33%) and 35 aseptic cases of RKA (67%). The bone defects were grouped into 17 AORI Type 2A (32.7%), 14 Type 2B (26.9%) and 21 Type 3 (40.4%). After a mean follow-up of 22 months (13.2-34.8; SD = ± 10), we had 4 surgical revisions (7.7%), 2 septic and 2 aseptic cases. The mean Oxford Knee Score was 28.6 points (8-47; SD = ± 10). 22 of 28 radiographs (78.6%) showed regular positioning of the cones and TKAs at a mean follow-up of 16.8 months (13.2-34.8; SD = ± 6). Three patients (10.7%) showed slight radiolucencies in the bone-cement interfaces and 3 patients (10.7%) had beginning heterotopic ossifications.

CONCLUSIONS

This study shows the initial clinical results of calcium-phosphate-coated tibia cones showing a good functional outcome. Further research should focus on long-term clinical and radiological follow-up.

Early Survivorship of Newly Designed Highly Porous Metaphyseal Tibial Cones in Revision Total Knee Arthroplasty

Background

Metaphyseal cones provide durable fixation in revision total knee arthroplasty (TKA). However, there is a paucity of data on the outcomes of a new porous cone design. As such, the goal of this study was to analyze the early survivorship in patients undergoing revision TKA with this cone.

Methods

We retrospectively reviewed 163 revision TKAs with a newly designed porous tibial cone from 2016 to 2018. Mean age was 67 years, and mean body mass index was 33 kg/m². Minimum follow-up duration was 2 years. Most patients were revised for aseptic loosening (46%), 2-stage periprosthetic joint infection (PJI) reimplantation (28%), or instability (15%). Most were varus-valgus constrained (65%) or hinged (32%) constructs. The majority had hybrid tibial stem fixation (74%). A multivariate Cox regression analysis was used to identify risk factors for reoperation.

Results

Survivorship free from re-revision for aseptic loosening, any nonmodular revision, and any reoperation was 100%, 96%, and 86% at 2 years, respectively. No patients were revised for aseptic loosening. Six (4%) tibial cones were removed for PJI, one of which was loose. There were 23 reoperations (14%), most commonly for PJI (10%). Multivariate analysis identified PJI reimplantation (hazard ratios [HR] = 4.2, P = .002), males (HR = 2.9, P = .02), and hinged constructs (HR = 2.7, P = .02) as significant risk factors for reoperation.

Conclusions

In a complex revision TKA cohort with a new highly porous tibial cone, in which most patients received hybrid stem fixation and nonlinked and linked constraint, there was 100% survival free from re-revision for aseptic loosening at 2 years. Longer term follow-up is required.

Short-term Outcomes of 3D-Printed Titanium Metaphyseal Cones in Revision Total Knee Arthroplasty

Recently, 3-dimensional (3D) printing technology has been used in the development of titanium metaphyseal cones to manage severe bone loss in revision total knee arthroplasty (rTKA). This study assessed (1) radiographs; (2) functional outcomes; (3) complications; and (4) 2-year implant survivorship in patients receiving 3D-printed titanium metaphyseal cones for moderate-to-severe tibial and femoral bone loss in rTKA. A single institution, retrospective chart review was performed for patients with large bone defects treated with a 3D-printed femoral or tibial titanium metaphyseal cone between 2015 and 2017 during rTKA (N=54). Paired sample t tests analyzed Knee Society Scores (KSS). Kaplan-Meier analyses determined implant survivorship when the endpoint was cone revision for aseptic loosening, cone revision for any reason, and reoperation for any reason. The authors found that 51 (98.1%) of 52 available radiographs demonstrated well-fixed components without any evidence of loosening or migration. Mean postoperative KSS scores were significantly higher when compared with preoperative scores (80.4 vs 52.0; P>.001). One patient experienced aseptic loosening of their cone. Seven additional cones were explanted as a consequence of reinfection, 1 of which was removed prior to arthrodesis. Cone survivorship was 98.5% when the endpoint was cone revision due to aseptic loosening, 88.2% when cone revision was due to any reason, and 77.9% for any reoperation. Metaphyseal cones appear to be well-suited for large bone defects during rTKA and the authors' findings suggest that cones may be a viable option for metaphyseal fixation during rTKA. Future studies should focus on their durability during a longer time period. [Orthopedics. 2021;44(1):43-47.].

Medium term clinical outcomes of tibial cones in revision knee arthroplasty

INTRODUCTION

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.

PATIENTS AND METHODS

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.

RESULTS

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.

DISCUSSION

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.

LEVEL OF EVIDENCE

4, retrospective study.

Use of porous custom-made cones for meta-diaphyseal bone defects reconstruction in knee revision surgery: a clinical and biomechanical analysis

INTRODUCTION

Although the practice of metaphyseal reconstruction has obtained successful clinical and radiological results in revision total knee surgery, off-the-shelf devices aren't an effective solution for all patients as they do not cover the full range of clinical possibilities. For this reason, during severe knee revisions, custom-made porous titanium cementless metaphyseal cones are nowadays employed as alternative to traditional surgeries. The aim of this study is to understand the benefits gained by the use of the custom-made cones against the performance of more traditional techniques, such as the use of cemented or cementless stems. Thus, a retrospective study on eleven patients and a biomechanical finite element analysis (FEA) was developed, based upon three clinical cases of the clinical analyzed cohort.

MATERIALS AND METHODS

Eleven patients underwent staged total knee arthroplasty revision with the use of 16 custom-made cones to correct severe femoral and tibial meta-diaphyseal bone defects. Clinical scores and range of movement were observed during the follow-up period (mean follow-up 26 ± 9.4 months). Reason for surgery was periprosthetic joint infection (PJI) in eight patients and post-traumatic osteomyelitis in the other three patients. Three patients previously affected by PJI were selected among the eleven patients of the clinical population. For those patients, bone geometries and implants during surgery were replicated in silico and analyzed during different daily activities. For the same patients, as alternative solution for surgery, the use of cemented or cementless stems was also simulated by FEA. Stress patterns in different region of interest and risk of fracture in the bone were calculated and compared.

RESULTS

No loosening, component migration, or mismatches between preoperative planning and intraoperative findings were clinically registered. Biomechanical results demonstrated that the use of custom-made cones induces a more homogeneously distributed bone stress than the other two techniques that concentrate the stress in spotted regions. The risk of fracture is comparable between the use of custom-made cones and cemented technique, while press-fit configurations increase the risk of fracture (more than 35%).

CONCLUSIONS

Based upon the clinical evidence and the findings after the FEAs, the practice of porous custom-made metaphyseal cones in severe revisions of knee arthroplasties is showing promising biomechanical results. The homogeneous stresses distributions and the lower bone stress gradient could justify a reduction of bone fractures and the risk of implant loosening which could be the explanation to the successful clinical outcomes.

Conservative two-stage revision with primary components of infected total hip arthroplasty: An analysis of survival, clinical and radiographic outcomes

Few studies provide an analysis of conservative two-stage revision of hip periprosthetic joint infection (PJI) and its impact on final outcome. A conservative revision is defined when soft tissues and bone quality enable the use of primary prosthetic components. Data of patients treated for chronic hip PJI who underwent two-stage revision between 2009 and 2016 and had a minimum of 2 years of follow-up were collected. Oxford Hip Score (OHS), Harris Hip Score (HHS) and radiological and microbiological data were retrieved and analysed. Clinical and functional outcome, survival, mortality, eradication, reinfection and re-revision rates within subgroups of patients with primary components and revision components are reported herein. A total of 148 patients underwent two-stage hip exchange with a mean follow-up of 55.6 ± 23.1 months and a mean age at surgery of 64.3 ± 12.7 years. Forty-four percent of patients underwent conservative revision. The mean HHS significantly improved from 40.6 ± 9.4 points to the final value of 87.8 ± 10.5 points (p = .002), and the mean OHS went from 20.3 ± 3.8 points to 40.3 ± 5. points (p< .001). Patients who were treated with primary components or isolated revision stems in the second stage had a significant reduction in surgical times (p< .001). The mortality rate for all causes of death was 6.8%, the eradication rate was 89.9%, the reinfection rate was 4.7% and the reoperation rate was 7.4% without differences between conservative and non-conservative revisions. Two-stage exchange arthroplasty for total hip arthroplasty (THA) PJI is a good strategy that provides satisfactory results, high eradication rates and no further need for revision. The conservative two-stage revision in patients with adequate bone stock represents a feasible option with good results and survival rates.

Bone Defects in Revision Total Knee Arthroplasty

The increase in the number of revision total knee arthroplasty surgeries has been observed in recent years, worldwide, for several causes. In the United States, a 601% increase in the number of total knee arthroplasties, between 2005 and 2030, is estimated. Among the enormous challenges of this complex surgery, the adequate treatment of bone defects is essential to obtain satisfactory and lasting results. The adequate treatment of bone defects aims to build a stable and lasting support platform for the implantation of the definitive prosthetic components and, if possible, with the reconstruction of bone stock. Concomitantly, it allows the correct alignment of the prosthetic and limb components, as well as restoring the height of the joint interline and, thus, restoring the tension of soft parts and load distribution to the host bone, generating a joint reconstruction with good function, stable, and painless. There are several options for the management of these bone defects, among them: bone cement with or without reinforcement with screws, modular metallic augmentations, impacted bone graft, structural homologous graft and, more recently, metal metaphyseal cones, and metaphyseal sleeves. The objective of the present article was to gather classic information and innovations about the main aspects related to the treatment of bone defects during revision surgeries for total knee arthroplasty.

Cup-on-cup technique: a reliable management solution for severe acetabular bone loss in revision total hip replacement

BACKGROUND

The management of acetabular bone loss is a challenging problem in revision total hip arthroplasty (rTHA). The goals of treatment are a stable acetabular fixation, implant stability, and restoration of hip centre of rotation.This study aims to report clinical, radiological outcomes and complications at short-term to mid-term follow-up of the cup-on-cup technique in the management of severe acetabular bone loss in rTHA.

METHODS

We retrospectively reviewed the records of patient receiving rTHA performed with double porous tantalum cup technique in a single Joint Replacement Unit from 2014 to 2017. Objective and subjective clinical scores (Harris Hip Score, Oxford Hip Score, and visual analogue scale), radiological parameters (centre of rotation, leg-length discrepancy, heterotopic ossification, osseointegration, loosening and radiolucencies) and complications were recorded. We analysed the implant survival rate and periprosthetic joint infection rate.

RESULTS

We included 9 patients (9 hips) with a mean follow-up of 35.3 ± 10.8 months. Functional scores showed a statistically significant improvement at the final follow-up (p < 0.01). All patients rated their surgery as satisfactory. The cup-on-cup construct demonstrated radiological osseointegration with the centre of rotation restoration and leg length discrepancy improvement. In 1 patient, periprosthetic joint infection was diagnosed and treated with suppressive antibiotic therapy. No patients underwent acetabular components revision surgery for any reason.

CONCLUSIONS

Cup-on-cup technique is a valid and safe solution for reconstruction of selected Paprosky type IIIA and IIIB bone defects with satisfactory clinical and radiographic results at short-term and mid-term follow-up.

Outcomes of a technique combining diaphyseal impaction grafting and metaphyseal cones for severe bone loss in revision total knee arthroplasty

Aims

Metaphyseal cones with cemented stems are frequently used in revision total knee arthroplasty (TKA). However, if the diaphysis has been previously violated, the resultant sclerotic canal can impair cemented stem fixation, which is vital for bone ingrowth into the cone, and long-term fixation. We report the outcomes of our solution to this problem, in which impaction grafting and a cemented stem in the diaphysis is combined with an uncemented metaphyseal cone, for revision TKA in patients with severely compromised bone.

Methods

A metaphyseal cone was combined with diaphyseal impaction grafting and cemented stems for 35 revision TKAs. There were two patients with follow-up of less than two years who were excluded, leaving 33 procedures in 32 patients in the study. The mean age of the patients at the time of revision TKA was 67 years (32 to 87); 20 (60%) were male. Patients had undergone a mean of four (1 to 13) previous knee arthroplasty procedures. The indications for revision were aseptic loosening (80%) and two-stage reimplantation for prosthetic joint infection (PJI; 20%). The mean follow-up was four years (2 to 11).

Results

Survival free from revision of the cone/impaction grafting construct due to aseptic loosening was 100% at five years. Survival free from any revision of the construct and free from any reoperation were 92% and 73% at five years, respectively. A total of six patients (six TKAs, 17%) required a further revision, four for infection or wound issues, and two for periprosthetic fracture. Radiologically, one unrevised TKA had evidence of loosening which was asymptomatic. In all unrevised TKAs the impacted diaphyseal bone graft appeared to be incorporated radiologically.

Conclusion

When presented with a sclerotic diaphysis and substantial metaphyseal bone loss, this technique combining diaphyseal impaction grafting with a metaphyseal cone provided near universal success in relation to implant fixation. Moreover, radiographs revealed incorporation of the bone graft and biological fixation of the cone. While long-term follow-up will be important, this technique provides an excellent option for the management of complex revision TKAs. Cite this article: Bone Joint J 2020;102-B(6 Supple A):116–122.

Midterm Results After Tantalum Cones in 1-Stage Knee Exchange for Periprosthetic Joint Infection: A Single-Center Study

BACKGROUND

The use of tantalum cones to reconstruct extensive bone defects in revision total knee arthroplasty has been established. We aimed to evaluate the midterm results after 1-stage knee exchange for periprosthetic joint infection using tantalum cones.

METHODS

Seventy-two patients (mean age, 70 ± 8.2 years) treated with a 1-stage exchange for infected total knee arthroplasty using porous tantalum cones, between 2011 and 2016, were retrospectively included. Either rotating or pure hinge system in combination with femoral and/or tibial cones was used. Survivorship analysis (septic and aseptic) was performed. Prospectively, functional outcome was assessed at a mean follow-up of 49.9 ± 18.8 months (range, 24-88).

RESULTS

A total of 15 patients (21%) were rerevised, 8 (11.1%) for infection and 7 (10%) for aseptic loosening, requiring cone exchange in 12 patients (17%). Cone-related survival free from any revision was 83% ± 3.8 standard deviation (95% confidence interval, 74-90), and infection-free survival was 89% ± 4.2 standard deviation (95% confidence interval, 76-93). No significant correlation was reported between the types of prosthesis used (P = .8) or implanted cones and failure (P = .6). History of a previous septic revision increased the risk of cone revision after the index surgery (P < .001). Preoperative Hospital for Special Surgery knee score improved from 47 ± 16 (range, 14-87) to 60 ± 17 (range, 24-84) points at the latest follow-up.

CONCLUSION

First study reports on outcomes of the 1-stage exchange using tantalum cones for knee periprosthetic joint infection with additional severe bone loss. Midterm cone-related and infection-free survival offered good results and provided reasonable functional outcomes.

Metaphyseal Fixation Using Highly Porous Cones in Revision Total Knee Arthroplasty: Minimum Two Year Follow Up Study

BACKGROUND

Highly porous metaphyseal cones have been introduced to restore metaphyseal integrity for improved cement interdigitation to achieve durable fixation in revision total knee arthroplasty (TKA). The purpose of this study is to review the survivorship, clinical results, and complications of revision TKA using highly porous 3-dimensionally printed titanium metaphyseal cones.

METHODS

This is a review of 62 revision TKAs using metaphyseal tibial cones, with 15 cases utilizing both tibial and femoral cones. The mean age of the patients was 66 years (range 32-84) who had a mean follow-up of 27 months (range 24-34). There were 38 women and 24 men, who had a mean body mass index of 33 (range 18.3-62).

RESULTS

Revision-free survival of the cones was 90.2%. If infection was excluded, survivorship was 100%. There were no cases of aseptic loosening. The mean Knee Society Score improved from 51 points preoperatively to 80 points at the time of latest follow-up. The mean Knee Society Functional Score improved from 48 points preoperatively to 68 points. A total of 15 of the 62 patients (24%) required additional surgery: 10 (16%) for infection, 3 (5%) for contracture, 1 for patellar subluxation, and 1 for quadriceps tendon rupture.

CONCLUSION

Metaphyseal fixation is important for survivorship in revision TKA which can be challenging due to cancellous and structural bone loss encountered at the time of revision. Prosthetic joint infection continues to be the leading cause of failure in revision TKA. The use of highly porous titanium metaphyseal cones produced from 3-dimensionally printed technology used in this study demonstrated excellent short-term results with no cases of aseptic loosening. Further follow-up is required to determine if these results can be durable over a longer period.

A review of materials for managing bone loss in revision total knee arthroplasty

In 2014-2015, 61,421 total knee arthroplasties (TKAs) were performed in Canada; an increase of about 20% over 2000-2001. Revision total knee arthroplasties (rTKAs) accounted for 6.8% of TKAs performed between 2014 and 2015, and this is estimated to grow another 12% by 2025. rTKAs are typically more complicated than primary TKAs due to the significant loss of femoral and tibial bone stock. The escalating demand and limitations associated with total knee arthroplasty and their revision drives the development of novel treatments. A variety of materials have been utilized to facilitate regeneration of healthy bone around the site of a knee arthroplasty. The selection of these materials is based on the bone defect size and includes bone grafts, graft substitutes and cements. However, all these materials have certain disadvantages such as blood loss, disease transmission (bone grafts), inflammatory response, insufficient mechanical properties (bone graft substitutes) thermal necrosis and stress shielding (bone cement). Recently, the use of metal augments for large bone defects has attracted attention, however they can undergo fretting, corrosion, and stress shielding. All things considered, this review indicates the necessity of developing augments that have structural integrities and biodegradation rates similar to that of human bone. Therefore, the future of bone loss management may lie in fabricating novel bioactive glass augments as they can promote bone healing and implant stability and can degrade with time.

Metaphyseal cones and sleeves in revision total knee arthroplasty: Two sides of the same coin? Complications, clinical and radiological results-a systematic review of the literature

Revision total knee arthroplasty (rTKA) is increasing of relevance in orthopaedic surgeon daily practice and this trend is likely to continue in the years ahead. The aim of this systematic review of English literature is to summarize and compare indications, complications, clinical and radiological results of metaphyseal cones and sleeves in management of bone loss in rTKA. Retrospective or prospective studies with at least 1 year of follow-up (FU) were included. The PRISMA 2009 flowchart and checklist were considered to edit the review. Clinical and radiological results, rates of intraoperative fractures, aseptic loosening, periprosthetic joint infection, septic failure, reoperations and re-revisions were extrapolated by the papers. Thirty-seven articles were included in the systematic review. Results of 927 cones (mean FU of 3.6 ± 1.4 years) and 1801 sleeves (mean FU of 4.5 ± 1.6 years) were analysed. The studies showed good clinical and functional outcomes. Cones and sleeves allowed a stable metaphyseal fixation. The aseptic survivorship of the implants was 97.3% in cones group and 97.8% in sleeves group. Metaphyseal cones and sleeves represent a viable option in management of type IIb and III AORI bone defects in aseptic and septic TKAr with overlapping survival rate. Further high-quality long-term studies would better clarify complications, clinical and radiological results of these promising techniques in revision total knee arthroplasty.