Total knee arthroplasty revision with trabecular tantalum cones: Preliminary retrospective study of 51 patients from two centres with a minimal 2-year follow-up

Porous Tantalum Metaphyseal Cones for Severe Femoral and Tibial Bone Defects in Revision Total Knee Arthroplasty are Reliable for Fixation at Mean 5-Year Follow-Up

BACKGROUND

Porous tantalum metaphyseal cones may facilitate reconstructions of severe bone defects during revision total knee arthroplasty (TKA), but there remains a paucity of data on their outcomes at mean 5 years of follow-up. This study reports the component survivorship, patient satisfaction, functional outcomes, radiographic osseointegration, and complications of revision TKA with porous tantalum metaphyseal cones at mid-term (mean 5-year) follow-up.

METHODS

This study included 152 patients who had a mean age of 66 years (range, 33 to 86 years) undergoing revision TKA with porous tantalum metaphyseal cones. Indications for surgery included aseptic loosening (n = 87, 57.3%), second-stage reimplantation for infection (n = 42, 27.6%), osteolysis with well-fixed components (n = 20, 13.2%), and periprosthetic fracture (n = 3, 2.0%). Component survivorship, clinical outcomes, radiographic outcomes, and any complications were recorded. The mean follow-up time was 5.6 years (range, 2.2 to 13.7).

RESULTS

Survivorship was 100% when the end point was revision of the metaphyseal cone (no cones were revised) and 83.8% (95% confidence interval: 77.9 to 90.2%) when the end point was reoperation for any reason at 5-year follow-up. Reoperations were performed for infection (n = 10), instability (n = 4), periprosthetic fracture (n = 2), and quadriceps rupture/dehiscence (n = 3). The mean patient satisfaction score was 78.8 ± 11.3 and the mean Forgotten Joint Score was 62.2 ± 16.7 at the final follow-up. The preoperative median University of California at Los Angeles score improved from 2 (interquartile range 2 to 3) to 6 points (interquartile range 5 to 6) (P < .001), and the preoperative Oxford knee score improved from 15.2 ± 3.8 to 39.4 ± 5.1 points (P < .001) at the final follow-up. All metaphyseal cones showed radiographic evidence of osteointegration without any subsidence or loosening.

CONCLUSIONS

Porous tantalum metaphyseal cones enabled robust reconstructions of severe femoral and tibial bone defects during revision TKA. These reconstructions were associated with excellent survivorship, improvements in functional outcomes, and reproducible radiographic osseointegration at mean 5-year follow-up. The most common reasons for reoperation were infection and instability.

Combined structural allograft and tantalum cone to manage segmental metaphyseal tibial bone defect in revision knee arthroplasty

Tibial bone defect remains a challenge in revision knee arthroplasty. The present innovative technique combines structural allograft and tantalum metaphyseal cone for treatment of AORI stage 2A and 2B (uncontained peripheral metaphyseal) tibial defect. The aim is to reconstitute bone stock and enhance allograft osseointegration, while limiting stress to the allograft by implanting the metaphyseal cone through the allograft and the original bone. LEVEL OF EVIDENCE: V (expert opinion).

Using novel porous metal pillars for tibial bone defects in primary total knee arthroplasty

BACKGROUND

The optimal method to treat tibial bone defects during primary total knee arthroplasty (TKA) is still unclear. A novel technique of porous metal pillar augmentation has been applied recently. This study aimed to assess the short-term outcomes of primary TKA with the use of novel porous metal pillars for tibial bone defects.

METHODS

A total of 24 cases (22 patients) of primary TKA between January 2019 and December 2020 using porous metal pillars for tibial bone defects were reviewed. Clinical results were evaluated using the Knee Society knee score (KSKS) and function score (KSFS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and range of motion (ROM). Hip-knee-ankle angle (HKAA), femorotibial angle (FTA), and radiolucent lines were assessed radiologically.

RESULTS

The median follow-up period was 36.0 months (interquartile range: 31-37 months). The KSKS, KSFS, WOMAC score, and ROM improved significantly at the final follow-up assessment compared with the preoperative evaluation. Both of the HKAA and FTA were corrected after surgery. Only one knee had a nonprogressive radiolucent line at the bone-cement interface. No radiolucent lines were detected around the pillar in any of the cases. There were no cases of prosthesis loosening and revision.

CONCLUSIONS

The use of novel porous metal pillars yielded satisfactory clinical outcomes and reliable radiological evidence of fixation in this study with a minimum 2-year follow-up. Porous metal pillar augmentation can be considered as a valuable and easy-to-use method for the management of tibial bone defects in primary TKA.

Metaphyseal cones and sleeves are similar in improving short- and mid-term outcomes in Total Knee Arthroplasty revisions

PURPOSE

The purpose of this systematic review and metanalysis was to assess clinical and radiological outcomes of metaphyseal sleeves and cones and to identify their possible advantages and disadvantages.

METHODS

A comprehensive search from the inception of the databases to March 2021 was performed on Medline, Scopus, CINAHL, Cochrane, Embase, Ovid, and Google scholar databases. Coleman Methodology Score was used for quality assessment. Author, year of publication, type of study, level of evidence, sample size, number of patients, number of knees treated, mean age, gender, mean follow-up, clinical outcomes, complications, the reason for revision and, type of prosthesis were extracted for analysis. Clinical studies providing data about patient's outcomes after the primary and Total Knee Arthroplasty revision with the usage of sleeves or cones and a minimum of 2 years of follow-up were included.

RESULTS

The literature search and cross-referencing resulted in a total of 93 articles, but only 30 articles were appropriate for the systematic review. Comparable clinical results were reported between cones and sleeves. The meta-analysis showed a greater incidence of intraoperative fractures in patients treated with sleeves (1.6%, [95% CI 0.7; 3.4] in cones and 4.6%, [95% CI 3.3; 6.4] in sleeves, p = 0.01), while the risk of postoperative fractures (4.3%, [95% CI 2.7; 7] in cones and 2.1%, [95% CI 1.2; 3.5] in sleeves, p = 0.04) and infections (8.5%, [95% CI 6; 12] in cones and 3.7%, [95% CI 2.1; 7.3] in sleeves, p = 0.03) was higher with cones.

CONCLUSION

A higher incidence of intraoperative fracture was reported in patients treated with sleeves, while a higher rate of postoperative fractures and infections was described in patients treated with cones. Nonetheless, complications were reported in both groups.

LEVEL OF EVIDENCE

III.

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

INTRODUCTION

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.

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).

RESULTS

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 ± 0.66 years. 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.

CONCLUSION

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.

LEVEL OF EVIDENCE

IV, case series.

The anatomical shape of the distal femur is an independent risk factor for aseptic loosening following one-stage septic knee revision using rotating hinge knee prosthesis

PURPOSE

Aseptic loosening (AL) is the second most common reason for failure after one-stage septic knee revision. In this context, the goal of the study is to identify risk factors for AL following one-stage septic knee revision using rotating hinge implants. We aimed to answer the following research question: How does the anatomical shape of the distal femur represent an independent risk factor for AL following one-stage septic knee revision arthroplasty?

METHODS

Patients, who had undergone re-revision surgery due to AL of the rotating hinge knee prosthesis after one-stage septic knee revision arthroplasty between January 2008 and December 2018, were included. For this purpose, 41 patients with AL after one-stage septic knee revision using rotating hinge implants and 37 controls without any revision surgery at latest follow-up were included in this study. Using standardized anteroposterior (AP) views of the knee in all patients, we measured the inner diameter of the femur 20 cm proximally from the joint line and at a point 2 cm proximally from the adductor tubercle.

RESULTS

Among the vast majority of AL cases, we identified an isolated loosening of the femoral component. The AL group showd a high distribution of the Type C according to the Citak classification with 75.7%. Contrary to this, with 24.3% (p < 0.001) the amount of Type C cases was relatively low in the control group. Consequently, Type C configurations of the distal femur represent an independent risk factor for AL with an approximately sevenfold higher risk for AL compareed to Type A and Type B.

CONCLUSIONS

The novel radiological classification system of the distal femur shows that the Type C subtype is an independent and main risk factor for AL after one-stage septic knee revision using rotating hinge knee implants.

Bone defect classifications in revision total knee arthroplasty, their reliability and utility: a systematic review

BACKGROUND

There are various classification systems described in the literature for managing bone defects in revision knee arthroplasty (RTKA). We analysed the reliability and usefulness of these classification systems.

QUESTIONS/PURPOSES

(1) To review and critique the various classification systems proposed for bone loss in RTKA. (2) Among all the proposed classifications which one is the most commonly used by surgeons to report their results. (3) What is the reliability of various bone defect classification systems for RTKA. In this review, we have assessed the studies validating those classifications with a detailed description of the limitations and the proposed modifications.

METHODS

This systematic review was conducted following PRISMA guidelines. Pubmed/Medline, CINAHL, EMBASE, Scopus, Cochrane databases and Web of Science databases were searched using multiple search terms and MeSH terms where possible. Studies meeting inclusion criteria were assessed for statistical parameters of reliability of a classification system.

RESULTS

We found 16 classification systems for bone defects in RTKA. Six studies were found evaluating a classification system with reporting their reliability parameters. Fifty-four studies were found which classified bone loss using AORI classification in their series. AORI classification is most commonly reported for classifying bone defects. Type T2B and F2B are the most common bone defects in RTKA. The average kappa value for AORI classification for femoral bone loss was 0.38 (0.27-0.50) and 0.76 (0.63-1) for tibial bone loss assessment.

CONCLUSION

None of the available classification systems is reliably established in determining the bone loss and treatment plans in RTKA. Among all, AORI classification is the most widely used system in clinical practice. The reliability of AORI Classification is fair for femoral bone loss and substantial for tibial bone loss.

Survival, functional outcome and satisfaction of first revision total knee arthroplasty at a mean eleven-year follow-up

PURPOSE

Providing long-term outcome data after rTKA and compare one- versus two-stage and septic versus aseptic revisions.

METHODS

This study represents a single-center retrospective study of first rTKAs performed for any reason with a final follow-up of a minimum of five years. Outcome parameters included stability assessment ROM, radiologic assessment, HSS score, KSS score, OKS score, EQ-5D-3L and VAS. 44 patients were included in the study. Subgroups analysis of one- versus two-stage revision and septic versus aseptic revision was performed.

RESULTS

The leading causes of rTKA in this mean 11 year follow-up study were aseptic loosening (36%) and periprosthetic joint infection (27%). At the final follow-up, there was a 89% survivorship of the implants. Patients showed a ROM of 114 ± 13°, HSS score of 78 ± 12, KKS objective score of 77 ± 16, KSS expectation and satisfaction score of 32 ± 11, KSS functional activity score of 50 ± 20, OKS of 30 ± 9, VAS of 53 ± 25 and EQ-5D index of 0.649. Functional outcome scores were not significantly altered in the analyzed subgroups.

CONCLUSIONS

In our 11 years follow-up, we obtained 89% implant survivorship. Measurements regarding functional outcome and pain showed results in the medium range of the respective scores, while patient satisfaction lay in the upper third. No significant differences in outcome scores between one- and two-stage revisions and septic versus aseptic revisions were observed. Level of Evidence Level III, retrospective cohort study.

Results of revision knee arthroplasty with individual implants

The aim of the study was to evaluate the long-term results of surgical treatment of patients with extensive bone defects (2B и 3 according to AORI) of the proximal tibia and/or distal femur using custom-made implants for revision knee arthroplasty. Material and methods. A retrospective clinical study was conducted in 24 patients who underwent revision arthroplasty using individual implants (9 femoral and 18 tibial) made on a 3D printer in the period from 2017 to 2021. T3 defect according to AORI classification was diagnosed in 12 patients (50%), F3 defect - in 1 (4.17%), F2B - in 8 (33.3%), T2B - in 6 (25%). All patients before surgery and 3, 6, 12 months after surgery were subjected to a questionnaire survey using the international scales VAS, KSS, WOMAC and SF-36. Results. At the follow-up examination 12 months after the operation, 9 out of 24 patients (37.510%) moved without additional means of support, 10 out of 24 (41.710%) with a cane, 4 out of 24 (16, 78%), walkers 1 out of 24 (4.210%). There were no periprosthetic fractures during surgery and in the postoperative period. Conclusion. The use of individual implants made using additive 3D printing technologies in revision knee arthroplasty in the presence of extensive bone defects (2B and 3 according to AORI) allows performing an organ-preserving operation without loss of the statodynamic function of the lower limb.

Clinical Outcomes of the Lateral Trabecular Metal Total Ankle Replacement at a 5-Year Minimum Follow-up

BACKGROUND

The Trabecular Metal (Zimmer Biomet, Warsaw, IN) total ankle arthroplasty (TAA) system uses a lateral approach with a fibular osteotomy to gain access to the tibiotalar joint and a sagittally curved tibial component. This is the first TAA system to laterally approach the ankle, and few studies have explored outcomes associated with this implant. This study aimed to report the 5-year clinical and radiographic outcomes as well as the survivorship of the implant.

METHODS

Over a 3-year period, 2 fellowship-trained foot and ankle surgeons used this implant system to treat 38 end-stage arthritic ankles. Reoperation and revision data were collected from all patients (100%) as part of the local prospective database. Patients completed the Foot and Ankle Outcome Score (FAOS) questionnaire preoperatively and at each annual follow-up visit; scores for a minimum of 5 years were available for 28 (73.7%) patients. A radiographic analysis compared postoperative coronal and sagittal alignment in weightbearing radiographs at a minimum of 5 years with that at 3 months postoperatively, as well as cyst or lucency formation, which was available for 21 patients (55.3%).

RESULTS

At 5 years, there were 3 revisions (7.9%) and 9 reoperations (23.7%). Reoperations included 4 fibular hardware removal and 5 medial gutter debridement procedures. The FAOS significantly improved for all domains (P < .05). Implant positioning did not significantly change between 3 months and 5 years postoperatively.

CONCLUSION

Our 5-year results in this small series using this unique prosthesis showed good overall survivorship (92.1%) and a reoperation rate of 23.7%, along with clinically significant improvement in patient-reported outcomes.

LEVELS OF EVIDENCE

Level IV: Retrospective case series.

Does the use of 3D-printed cones give a chance to postpone the use of megaprostheses in patients with large bone defects in the knee joint?

Revision procedures and the resulting bone loss are a big challenge for orthopedic surgeons. Therefore, we checked what functional outcomes that 3D-printed cone augments can offer to patients with bone defects (Anderson Orthopedic Research Institute [AORI] classification type 2B and 3) in the knee and whether the use of cones can delay the necessity to use a megaprotheses. Data from 64 patients (M = 22; W = 42) who underwent total knee arthroplasty (TKA) revision were included in the analysis. The Knee Society Clinical Rating System (KSS) and the range of motion in the knee joint were used for the functional assessment. The mean follow-up was 28 months (range: 18–44 months). The survival rate for aseptic loosening at follow-up was 100%. Infection occurred in two (3.1%) patients. The mean KSS score increased from 12.75 points preoperatively to 66.56 postoperatively (p < 0.001). The mean range of motion in the knee changed from 61.15° preoperatively to 115.93° postoperatively (p < 0.001). 3D-printed cone augments seem to be a good solution for patients requiring a TKA revision procedure. When used in patients with bone defects classified as 2B and 3 (AORI), they can be a good alternative, delaying the need for megaprotheses.

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.

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.

Management of bone loss in revision total knee arthroplasty: therapeutic options and results

The treatment of small to moderate size defects in revision total knee arthroplasty (rTKA) has yielded good results with various techniques (cement and screws, small metal augments, impaction bone grafting and modular stems). However, the treatment of severe defects remains problematic.

Severe defects have typically been treated with large allograft and metaphyseal sleeves. The use of structural allograft has decreased in recent years due to increased long-term failure rates and the introduction of highly porous metal augments (cones and sleeves).

A systematic review of level IV evidence studies on the outcomes of rTKA metaphyseal sleeves found a 4% rate of septic revision, and a rate of septic loosening of the sleeves of 0.35%. Aseptic re-revision was required in 3% of the cases. The rate of aseptic loosening of the sleeves was 0.7%, and the rate of intraoperative fracture was 3.1%. The mean follow-up was 3.7 years.

Another systematic review of tantalum cones and sleeves found a reoperation rate of 9.7% and a 0.8% rate of aseptic loosening per sleeve. For cones, the reoperation rate was 18.7%, and the rate of aseptic loosening per cone was 1.7%.

The reported survival of metal sleeves was 99.1% at three years, 98.7% at five years and 97.8% at 10 years. The reported survival free of cone revision for aseptic loosening was 100%, and survival free of any cone revision was 98%. Survival free of any revision or reoperation was 90% and 83%, respectively.

Cite this article: EFORT Open Rev 2021;6:1073-1086. DOI: 10.1302/2058-5241.6.210007

The Use of Metaphyseal Cones and Sleeves in Revision Total Knee Arthroplasty

The burden of revision total knee arthroplasty (rTKA) is expected to increase with the rise in the number of TKA procedures being performed yearly. Management of bone loss during rTKA is challenging and necessitates appropriate surgical planning. Metaphyseal cones and sleeves have emerged as an increasing popular option for addressing metaphyseal femoral and tibial bone loss when performing rTKA. Understanding what cones and sleeves are commercially available and when to use them are critical parts of preoperative evaluation and planning. The purpose of this comprehensive review was to present different design philosophies, types of manufacturing, clinical outcomes, and the versatility and interchangeability of varying cones and sleeves with different TKA revision systems.

Aseptic Loosening of Porous Metaphyseal Sleeves and Tantalum Cones in Revision Total Knee Arthroplasty: A Systematic Review

Bone loss often complicates revision total knee arthroplasty (TKA). Management of metaphyseal defects varies, with no clearly superior technique. Two commonly utilized options for metaphyseal defect management include porous-coated metaphyseal sleeves and tantalum cones. A systematic review was conducted according to the international Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We combined search terms "Total knee arthroplasty" AND/OR "Sleeve," "Cone" as either keywords or medical subject heading (MeSH) terms in multiple databases according to PRISMA recommendations. All retrieved articles were reviewed and assessed using defined inclusion and exclusion criteria. A total of 27 studies (12 sleeves and 15 cones) of revision TKAs were included. In the 12 studies on sleeve implantation in revision TKAs, 1,617 sleeves were implanted in 1,133 revision TKAs in 1,025 patients. The overall rate of reoperation was 110/1,133 (9.7%) and the total rate of aseptic loosening per sleeve was 13/1,617 (0.8%). In the 15 studies on tantalum cone implantation in revision TKAs, 701 cones were implanted into 620 revision TKAs in 612 patients. The overall rate of reoperation was 116/620 (18.7%), and the overall rate of aseptic loosening per cone was 12/701 (1.7%). Rates of aseptic loosening of the two implants were found to be similar, while the rate of reoperation was nearly double in revision TKAs utilizing tantalum cones. Variability in the selected studies and the likely multifactorial nature of failure do not allow for any definitive conclusions to be made. This review elucidates the necessity for additional literature examining revision TKA implants.

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.

[Economic evaluation of porous metal cones in total knee arthroplasty]

INTRODUCTION

The use of porous metal cones (PMC) to fill bone loss during knee replacements is increasing, but these medical devices are not reimbursed in addition to diagnosis related tariffs (DRTs). The economic impact of PMC may be significant for hospitals.

MATERIAL AND METHODS

This multicenter observational study includes all patients who benefited of a total knee prosthesis, with reconstruction by PMC, between June 2014 and June 2019, in two French university hospitals. The costs of each diagnosis related group (DRG) was evaluated using the "étude nationale des coûts à méthodologie commune (ENC)". The PMC costs were compared with the amounts of DRG and with the fares perceived by the hospital from the French sickness fund (DRTs).

RESULTS

96 patients (103 stays) benefited from the implantation of 195 cones. The hospital incomes were 10,970±1401€ /stay. Spending associated with PMC represented 35% of DRGs and 44% of DRTs. The average additional cost related to the cones was 2709±1138€ /stay. If the reconstructions had been performed by allograft, the average gain for hospitals would have been 108€ /stay.

CONCLUSION

If PMC have clinical benefits for surgeons in reducing the incidence of revision, this study shows the inadequacy of the funding of these devices for French hospitals. This suggests the need to expand the possibilities of supporting innovative technologies.

Rotating-hinge prosthesis for aseptic revision knee arthroplasty: A multicentre retrospective study of 127 cases with a mean follow-up of five years

BACKGROUND

The use of third-generation rotating-hinge knee prostheses has increased considerably in recent years. The more anatomical design of these prostheses, together with their controlled rotation system that reduces constraints generated by the single degree of liberty, have produced better outcomes. The objective of this study was to evaluate the clinical and radiological outcomes of revision knee arthroplasty for aseptic failure using rotating-hinge prostheses.

HYPOTHESIS

The rotating-hinge knee prostheses currently used in France provide significant improvements in function and self-sufficiency of patients undergoing revision knee arthroplasty, with outcomes comparable to those reported with constrained condylar knees.

MATERIAL AND METHODS

A multicentre retrospective study was conducted in 17 centres, under the auspices of the SoFCOT. The cohort consisted of 127 patients (127 knees) operated on before 2013. The main reasons for knee revision were aseptic loosening, major instability, mechanical failure, and extensor apparatus failure. Function and self-sufficiency were assessed using the International Knee Society (IKS) score and the Devane score, respectively. Survival was defined with all-cause surgical revision as the end point.

RESULTS

Mean follow-up was 67.3±11.8 months (range, 13-180 months). Significant improvements (p<0.001) were seen in the total IKS score (+42 points), the IKS function score (+12 points), and the knee IKS score (+30 points). Paradoxically, the Devane score decreased by 0.44 point. The 5-year survival rate was 77% (95% confidence interval, 0.70-0.85). Postoperative complications developed in 29% of patients (infection, n=12; aseptic loosening, n=11; and fracture, n=7).

DISCUSSION

Rotating-hinge prostheses provide satisfactory outcomes of knee arthroplasty revision and remain an effective option for complex cases, confirming our working hypothesis. Self-sufficiency diminishes slightly. The long-term outcomes obtained using rotating-hinge prostheses are, however, less satisfactory than those observed with constrained condylar knees for aseptic TKA revision, and the complication rate is higher, although the population and local circumstances are different. Discernment is therefore in order when determining the indications of rotating-hinge prostheses.

LEVEL OF EVIDENCE

IV; retrospective cohort study.

Midterm Outcomes of Tantalum Metal Cones for Severe Bone Loss in Complex Primary and Revision Total Knee Arthroplasty

Background

Managing severe periarticular bone loss poses a major challenge in complex primary and revision total knee arthroplasty (TKA). Impaction bone graft, structural allografts, metal augments, and mega prosthesis are some of the methods used to address major bone loss. Tantalum metal (TM) Cones (Zimmer, Warsaw, IN) were introduced as an alternative to address this cohort of patients. The advantages of these cones include excellent biocompatibility, high porosity with osteoconductive potential, and a modulus of elasticity between cortical and cancellous bone. In addition, it is bioactive and offers an intrinsically high friction fit.

Methods

A cohort of 62 patients with severe distal femoral and proximal tibial bone loss were operated for primary and revision TKA between January 2007 and December 2014 and followed up for a mean period of 108.5 months (range: 60-156 months). Preoperative and postoperative range of motion and Knee Society score were documented. Postoperatively long leg X-rays were performed at each follow-up visit to determine osteointegration, evidence of loosening, and migration.

Results

The range of motion and Knee Society score improved considerably from preoperative a value of 63.9 ± 13.9° and 52 ± 14.9 to 102.1 ± 9.9° and 76.1 ± 10.03, respectively, at the final follow-up visit in the primary cohort and 52.14 ± 13.3° and 38.1 ± 9.1 to 92 ± 8° and 68.5 ± 4.3, respectively, in the revision cohort. Serial radiographs demonstrated complete osteointegration of the TM cones at the final follow-up.

Conclusions

Our study demonstrates excellent midterm survivorship of TM cones with predictable osteointegration and good outcomes (clinical and radiological) in treatment of severe femoral and tibial metaphyseal bone defects in complex primary and revision TKAs.

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.].

Knee arthroplasty for acute fractures around the knee

Results of open reduction and internal fixation for complex articular fractures around the knee are poor, particularly in elderly osteoporotic patients.

Open reduction and internal fixation may lead to an extended hospital stay and non-weight-bearing period.

This may lead to occurrence of complications related to decubitus such as thrombo-embolic events, pneumonia and disorientation.

Primary arthroplasty can be a valuable option in a case-based and patient-specific approach. It may reduce the number of procedures and allow early full weight-bearing, avoiding the above-mentioned complications.

There are four main indications:

1) Elderly (osteoporotic) patients with pre-existing (symptomatic) end-stage osteoarthritis.

2) Elderly (osteoporotic) patients with severe articular and metaphyseal destruction.

3) Pathological fractures of the distal femur and/or tibia.

4) Young patients with complete destruction of the distal femur and/or tibia.

The principles of knee (revision) arthroplasty should be applied; choice of implant and level of constraint should be considered depending on the type of fracture and involvement of stabilizing ligaments. The aim of treatment is to obtain a stable and functional joint.

Long-term data remain scarce in the literature due to limited indications.

Cite this article: EFORT Open Rev 2020;5:713-723. DOI: 10.1302/2058-5241.5.190059

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.

Why Reintervention After Total Knee Arthroplasty Fails? A Consecutive Cohort of 1170 Surgeries

BACKGROUND

The aim of this study was to analyze why contemporary reintervention after total knee arthroplasty (RiTKA) fails.

METHODS

Between January 2006 and December 2010, from a multicenter cohort of 1170 RiTKAs, we assessed all failures of RiTKA requiring additional surgery. All indications for the index reintervention were included. The minimum follow-up period was 3 years.

RESULTS

A total of 192 (16.4%) patients required additional surgery after RiTKA (re-reintervention). The mean follow-up period was 7.7 years. Mean age was 69.2 years. The mean time to re-reintervention was 9.6 months with 90.1% of rTKA failure occurring within the first two years. Infection was the main cause of new surgery after RiTKA (47.9%; n = 92/192). Other causes included extensor mechanism pathology (14.6%), stiffness (13.5%), pain (6.8%), aseptic loosening (5.2%), laxity (5.2%), periprosthetic fracture (3.6%), and wound pathology (3.1%). In four groups, the main indication for re-reintervention was recurrence of the pathology leading to the first reintervention: RiTKA for infection (59/355, 16.6%, P < .05), stiffness (18/174, 10.3%, P < .05), extensor mechanism failure (9/167, 5.4%, P < .05), and RiTKA for pain (4/137, 2.9%, P = .003). Global survival curve analysis found 87.9% survivorship without re-reintervention at one year and 83% at eight years.

CONCLUSION

Contemporary RiTKA failures mainly occur in the first two postoperative years. Infection is the main cause of failure in RiTKA. Recurrence of the initial pathology occurs in four groups of RiTKA and is the main indication for re-reintervention in these groups; infection (16.6%), stiffness (10.3%), extensor mechanism failure (5.4%), and pain (2.9%).

Diagnosis and management of implant debris-associated inflammation

Introduction: Total joint replacement is one of the most common, safe, and efficacious operations in all of surgery. However, one major long-standing and unresolved issue is the adverse biological reaction to byproducts of wear from the bearing surfaces and modular articulations. These inflammatory reactions are mediated by the innate and adaptive immune systems.Areas covered: We review the etiology and pathophysiology of implant debris-associated inflammation, the clinical presentation and detailed work-up of these cases, and the principles and outcomes of non-operative and operative management. Furthermore, we suggest future strategies for prevention and novel treatments of implant-related adverse biological reactions.Expert opinion: The generation of byproducts from joint replacements is inevitable, due to repetitive loading of the implants. A clear understanding of the relevant biological principles, clinical presentations, investigative measures and treatments for implant-associated inflammatory reactions and periprosthetic osteolysis will help identify and treat patients with this issue earlier and more effectively. Although progressive implant-associated osteolysis is currently a condition that is treated surgically, with further research, it is hoped that non-operative biological interventions could prolong the lifetime of joint replacements that are otherwise functional and still salvageable.

Porous Tantalum and Titanium in Orthopedics: A Review

Porous metal is metal with special porous structures, which can offer high biocompatibility and low Young's modulus to satisfy the need for orthopedic applications. Titanium and tantalum are the most widely used porous metals in orthopedics due to their excellent biomechanical properties and biocompatibility. Porous titanium and tantalum have been studied and applied for a long history until now. Here in this review, various manufacturing methods of titanium and tantalum porous metals are introduced. Application of these porous metals in different parts of the body are summarized, and strengths and weaknesses of these porous metal implants in clinical practice are discussed frankly for future improvement from the viewpoint of orthopedic surgeons. Then according to the requirements from clinics, progress in research for clinical use is illustrated in four aspects. Various creative designs of microporous and functionally gradient structure, surface modification, and functional compound systems of porous metal are exhibited as reference for future research. Finally, the directions of orthopedic porous metal development were proposed from the clinical view based on the rapid progress of additive manufacturing. Controllable design of both macroscopic anatomical bionic shape and microscopic functional bionic gradient porous metal, which could meet the rigorous mechanical demand of bone reconstruction, should be developed as the focus. The modification of a porous metal surface and construction of a functional porous metal compound system, empowering stronger cell proliferation and antimicrobial and antineoplastic property to the porous metal implant, also should be taken into consideration.

Revision total knee arthroplasty (TKA): mid-term outcomes and bone loss/quality evaluation and treatment

Background

Revision total knee arthroplasty (rTKA) is a demanding procedure, with a high complication and failure rate and a high rate of bone losses and poor bone quality. Different classifications for bone losses have been proposed, but they do not consider bone quality, which may affect implant fixation. The aim of this study is to describe the outcomes of a consecutive series of rTKA. Furthermore, a modified bone loss classification will be proposed based also on bone quality. Finally, the association between radiolucent line (RLL) development and different risk factors will be evaluated.

Methods

All the patients who underwent rTKA between 2008 and 2016 in the same institution were included. rTKAs were performed by the same surgeon according to the three-step technique. Bone losses were classified according to the proposed classification, including bone quality evaluation. The Knee Scoring System (KSS), the Hospital for Special Surgery Knee Score (HSS), and the SF-12 were used for the clinical evaluation. Radiological evaluation was performed according to the Knee Society Roentgenographic Evaluation System. Different possible risk factors (i.e., gender, age, amount of bone losses) associated to RLL development were identified, and this association was evaluated using logistic regression.

Results

Fifty-one patients (53 knees) were included (60.8% female, average age 71.5 years). The average follow-up was 56.6 months (range 24–182). The most frequent cause of failure was aseptic loosening (41.5%). 18.9% of the cases demonstrated poor bone quality. Bone losses were treated according to the proposed algorithm. In all the cases, there was a significant improvement in all the scores (P < 0.05). The average post-operative range of motion was 110.5° (SD 10.7). At the radiological evaluation, all the implants resulted well aligned, with 15.1% of non-progressive RLL. There were 2 failures, with a cumulative survivorship of 92.1% at the last follow-up (SD 5.3%). At the logistic regression, none of the evaluated variables resulted associated to RLL development.

Conclusion

rTKA is a demanding procedure, and adequate treatment of bone losses is mandatory to achieve good results. However, also bone quality should be taken into consideration when approaching bone losses, and the proposed classification may need surgeons after an adequate validation.

Level of evidence

Level IV

The role of rotating hinge implants in revision total knee arthroplasty

Hinged implants are the most constrained knee replacement prostheses. They are very useful in complex cases of total knee arthroplasty (TKA) revision.

Hinged implants have evolved with rotating bearings and modularity that allows local joint reconstruction or segmental bone replacement.

They are required when significant instability persists in cases with inadequate collateral ligaments and significant flexion laxity.

They are now used when a large bone defect is reconstructed, or when bone fixation of the implant is questionable especially in the metaphyseal zone.

The use of hinged implants in TKA revision is associated with high complication rates. Published outcomes differ based on the patients’ aetiology.

The outcomes of rotating-hinged implants used in septic revisions or salvage situations are poorer than other types of revision and have a higher complication rate.

The poor general health of these patients is often a limitation.

Despite these relatively poor results, hinged implants continue to have a place in revision surgery to solve major instability or to obtain stable bone fixation of an implant when the metaphysis is filled with bone grafts or porous devices.

Cite this article: EFORT Open Rev 2019;4 DOI: 10.1302/2058-5241.4.180070

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.

Vancomycin elution kinetics from porous tantalum metal

Revisions TKAs are being completed with uncemented constructs more frequently. We hypothesized that tantalum cones could be an efficient carrier of antibiotics in uncemented procedures. We aimed to compare the release of vancomycin between (i) tantalum and smooth stainless cylinders; (ii) different concentrations of vancomycin; and (iii) different durations of bathing. Specifically designed tantalum cylinders were bathed in a vancomycin solution with various durations of baths. We investigated rinses between each interval as well as the dose of vancomycin. Vancomycin concentrations were determined in each group by fluorescence polarization immunoassay at different intervals (1 h, days 1, 2, 3, 5). At 1 h, the mean vancomycin concentration for the 1-hour soaking group was 3,172 μg/ml, whereas mean concentration for the smooth stainless steel group was 39.37 μg/ml (p < 0.001). The rinsing group showed a significantly lower concentration at 1 h and 1 day (p < 0.05). The 2-gram vancomycin group showed no difference at days 1, 2, and 3 compared to the 1-hour group. The 5, 15, and 30-minute bathing groups showed significantly lower vancomycin concentrations at all-time points. All vancomycin concentrations at day 3 were superior to the minimal inhibitory concentration of Staphyloccocus aureus. The mean concentration of vancomycin depends on the material, duration of bathing, the rinsing effect, and the drug dose. Our in-vitro study is the first to show that porous tantalum cylinders allow antibiotic carriage and progressive release. If appearing in vivo, in a similar extent, this intrinsic property might be useful to prevent and/or treat peri-prosthetic joint infection. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:308-312, 2019.

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

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

Porous metal cones: gold standard for massive bone loss in complex revision knee arthroplasty? A systematic review of current literature

INTRODUCTION

Revision knee arthroplasty is increasing, and in that case, bone loss management is still a challenging problem. In the last years, the body of literature and interest surrounding porous metal cones has grown, but few systematic evaluations of the existing evidence have been performed. The aim of our systematic review is to collect and critically analyze the available evidence about metal cones in revision knee arthroplasty especially focusing our attention on indications, results, complications, and infection rate of these promising orthopaedic devices.

MATERIALS AND METHODS

We performed a systematic review of the available English literature, considering the outcomes and the complications of tantalum cones. The combinations of keyword were "porous metal cones", "knee revision", "bone loss", "knee arthroplasty", "periprosthetic joint infection", and "outcome".

RESULTS

From the starting 312 papers available, 20 manuscripts were finally included. Only one included study has a control group. The main indication for metal cones is type IIb and III defects according AORI classification. Most of the papers show good clinical and radiological outcomes with low rate of complications.

CONCLUSION

The examined studies provide encouraging clinical and radiological short-to-mid-term outcomes. Clinical studies have shown a low rate of aseptic loosening, intraoperative fractures, infection rate and a lower failure rate than the previous treatment methods. Higher quality papers are needed to draw definitive conclusions about porous metal cones.

Revision total knee arthroplasty with porous-coated metaphyseal sleeves provides radiographic ingrowth and stable fixation

PURPOSE

Porous-coated metaphyseal sleeves are designed to fill bone defects and facilitate osseointegration when bone loss in encountered during revision total knee arthroplasty (TKA). The purpose of this study is to evaluate short-term results of porous-coated metaphyseal sleeves with regards to implant fixation and clinical outcomes.

METHODS

A retrospective review was conducted on 50 patients (79 sleeves-49 tibial and 30 femoral) who had a press-fit metaphyseal sleeve with revision TKA. Tibial and femoral bone loss was classified according to the Anderson Orthopaedic Research Institute (AORI) bone defect classification. Post-operative complications of infection, revision surgery, and dislocation were assessed. Follow-up radiographs were evaluated for signs of loosening using the criteria developed by the Knee Society. The median follow-up was 58.8 months (range 25.8-93.0 months).

RESULTS

The bone loss classifications were 1 type 1, 30 type 2a, 2 type 2b, and 17 type 3, and with regards to the femur, 5 were type 1, 8 type 2a, 31 type 2b, and 6 type 3. At final follow-up, 41/45 (91.1%) tibial and 28/29 (96.6%) femoral sleeves showed radiographic evidence of ingrowth. Of these 69 patients, all showed radiographic evidence of bony ingrowth. Three sleeves were revised for infection and two for loosening. The re-operation rate for loosening was 5/74 (6.8%) and for any reason was 14/74 (18.9%).

CONCLUSIONS

Modular porous-coated press fit metaphyseal sleeves fill defects and provide evidence of radiographic ingrowth. Short-term stable fixation can be achieved with sleeves, which is helpful as more patients undergo revision total knee arthroplasty with greater bone loss. Longer duration studies are needed to ascertain the survival rate of these implants.

LEVEL OF EVIDENCE

IV.

Comparison of mode of failure between primary and revision total knee arthroplasties

INTRODUCTION

Cognizance of common reasons for failure in primary and revision TKA, together with their time course, facilitates prevention. However, there have been few reports specifically comparing modes of failure for primary vs. revision TKA using a single prosthesis. The goal of the study was to compare the survival rates, modes of failure, and time periods associated with each mode of failure, of primary vs. revision TKA.

HYPOTHESIS

The survival rates, modes of failure, time period for each mode of failure, and risk factors would differ between primary and revision TKA.

MATERIAL AND METHODS

Data from a consecutive cohort comprising 1606 knees (1174 patients) of primary TKA patients, and 258 knees (224 patients) of revision TKA patients, in all of whom surgery involved a P.F.C^® prosthesis (Depuy, Johnson & Johnson, Warsaw, IN), was retrospectively reviewed. The mean follow-up periods of primary and revision TKAs were 9.2 and 9.8 years, respectively.

RESULTS

The average 10- and 15-year survival rates for primary TKA were 96.7% (CI 95%,±0.7%) and 85.4% (CI 95%,±2.0%), and for revision TKA 91.4% (CI 95%,±2.5%) and 80.5% (CI 95%,±4.5%). Common modes of failure included polyethylene wear, loosening, and infection. The most common mode of failure was polyethylene wear in primary TKA, and infection in revision TKA. The mean periods (i.e., latencies) of polyethylene wear and loosening did not differ between primary and revision TKAs, but the mean period of infection was significantly longer for revision TKA (1.2 vs. 4.8 years, P=0.003).

DISCUSSION

Survival rates decreased with time, particularly more than 10 years post-surgery, for both primary and revision TKAs. Continuous efforts are required to prevent and detect the various modes of failure during long-term follow-up. Greater attention is necessary to detect late infection-induced failure following revision TKA.

LEVEL OF EVIDENCE

Case-control study, Level III.

Poor outcomes of fusion with Trabecular Metal implants after failed total ankle replacement: Early results in 11 patients

INTRODUCTION

One of the reasons for revision of total ankle replacement (TAR) implants is loosening due to subchondral cysts. Reconstruction and fusion of the ankle is often the first choice for revision procedures due to the large bone defects, which are typically filled with autograft and/or allograft. Filling the defect with a trabecular metal tantalum implant is a potential alternative given the biomechanical properties of this component.

HYPOTHESIS

Using tantalum as a spacer provides primary stability and contributes to fusion of the ankle joint after removal of failed TAR implants.

METHODS

Eleven patients underwent arthrodesis an average of 6.9 years after TAR. The mean height of the bone defect was 32mm. It was filled with a specially designed quadrangular implant (Trabecular Metal™, Zimmer/Biomet) combined with an iliac crest graft. Ten patients underwent tibio-talo-calcaneal (TTC) arthrodesis fixed with an angled retrograde nail and one patient underwent talocrural arthrodesis fixed with two plates (anterolateral and anteromedial). The clinical, functional (AOFAS and SF36 scores) and radiological (plain X-rays and CT scan) outcomes were determined.

RESULTS

At a mean follow-up of 19.3 months, the mean total AOFAS score was 56 (21-78) and the mean SF36 score was 60.5 (19-84). One patient was lost to follow-up and four patients still had pain. The tantalum implant was integrated in six patients. Five patients achieved fusion of the subtalar joint and 8 achieved fusion of the talocrural joint. Three patients required surgical revision.

DISCUSSION

Our hypothesis was not confirmed. The clinical outcomes after more than 1 year of follow-up are disappointing, as was the large number of nonunion cases and the lack of tantalum integration. These technical failures can be explained by insufficient construct stability and/or insufficient implant porosity.

LEVEL OF EVIDENCE

IV (retrospective cohort study).

Primary total knee arthroplasty for acute fracture around the knee

Relatively poor results have been reported with open reduction and internal fixation of complex fractures around the knee in elderly osteoporotic patients, and primary total knee arthroplasty (TKA) has been proposed as an alternative solution. While limiting the number of procedures, it meets two prerequisites: (1) to save the patient's life, thanks to early weight-bearing, to limit decubitus complications; and (2) to save knee function and patient autonomy, thanks to early knee mobilization. There are 3 main indications: complex articular fractures in elderly patients with symptomatic osteoarthritis prior to fracture; complex articular fractures of the tibial plateau in elderly patients whose bone quality makes internal fixation hazardous; and major destruction of the distal femur in younger patients. Although admitted in emergency, these patients require adequate preoperative management, including a multidisciplinary approach to manage comorbidities, control of anemia and pain, and assessment and management of vascular and cutaneous conditions. Preoperative planning is crucial, to order appropriate implants and materials that may be needed intraoperatively. Surgical technique is based on the basic principles of revision surgery as regards choice of implant, steps of reconstruction, bone defect management and implant fixation. For complex fractures of the distal femur, primary temporary reduction is a useful "trick", to determine the level of the joint line and femoral rotation. Complementary internal fixation may be required in case of diaphyseal extension of the fracture and to prevent inter-prosthetic fractures. In the literature, the results of primary TKA for fracture are encouraging and better than for secondary TKA after failure of non-operative treatment or internal fixation, with lower rates of revision and complications, earlier full weight-bearing and better functional results. Loss of autonomy is, however, frequent, and 1-year mortality is high, especially following complex femoral fractures in the elderly.

Management of metaphyseal bone loss in revision knee arthroplasty

Background and aim of the work: Revision total knee arthroplasty (TKA) is usually made more complex by the presence of bone defects, which may be caused by periprosthethic infection, polyethylene wear, implant loosening or fractures. The main aim of the present work is to review the available literature to understand the current options to manage with the bone loss during knee revisions. Methods: Available English literature for bone defects in revision TKAs has been evaluated looking at treatment options and their results in terms of clinical and radiological outcomes and failure rates. Results: Anderson Orthopaedic Research Institute (AORI) classification is the most frequently used because it helps in the choice of the most suitable treatment. Several options are available in the management of metaphyseal bone loss in revision knee arthroplasty. For small and contained defects (AORI type 1) cement with or without screws and auto- or allograft morcellized bone are available. In uncontained but mild defects (AORI type 2A) metal augments should be use while large and uncontained defects (AORI type 2B and 3) are best addressed with structural allograft or metal filling devices (cones and sleeves). Stemmed components, either cemented or cementless, are recommended to reduce the strain at the interface implant-host. Conclusions: The treatment of bone defects in revision TKAs has evolved during the last years providing different options with good results at a short/medium term follow up. With the increasing revision burden, further scientific evidence is requested to identify the best approach for each patient. Long-term clinical outcome as well as implant survival after revision TKA are still sub-optimal and depend upon many factors including cause for revision, surgical approach, type of implants used and various patient factors. (www.actabiomedica.it)

Management of metaphyseal bone loss in revision knee arthroplasty

BACKGROUND AND AIM OF THE WORK

Revision total knee arthroplasty (TKA) is usually made more complex by the presence of bone defects, which may be caused by periprosthethic infection, polyethylene wear, implant loosening or fractures. The main aim of the present work is to review the available literature to understand the current options to manage with the bone loss during knee revisions.

METHODS

Available English literature for bone defects in revision TKAs has been evaluated looking at treatment options and their results in terms of clinical and radiological outcomes and failure rates.

RESULTS

Anderson Orthopaedic Research Institute (AORI) classification is the most frequently used because it helps in the choice of the most suitable treatment. Several options are available in the management of metaphyseal bone loss in revision knee arthroplasty. For small and contained defects (AORI type 1) cement with or without screws and auto- or allograft morcellized bone are available. In uncontained but mild defects (AORI type 2A) metal augments should be use while large and uncontained defects (AORI type 2B and 3) are best addressed with structural allograft or metal filling devices (cones and sleeves). Stemmed components, either cemented or cementless, are recommended to reduce the strain at the interface implant-host.

CONCLUSIONS

The treatment of bone defects in revision TKAs has evolved during the last years providing different options with good results at a short/medium term follow up. With the increasing revision burden, further scientific evidence is requested to identify the best approach for each patient. Long-term clinical outcome as well as implant survival after revision TKA are still sub-optimal and depend upon many factors including cause for revision, surgical approach, type of implants used and various patient factors.