High-flexion Total Knee Arthroplasty Research Articles

Long-Term Outcomes of High-Flexion Design Total Knee Arthroplasty with a Short Posterior Flange.

The purpose of this study was to evaluate the clinical and radiological outcomes of high-flexion total knee arthroplasty (TKA) using Vega Knee System (B. Braun, Aesculap) at a long-term follow-up and to analyze the implant survivorship. We enrolled 165 patients (232 knees) with a minimum 7-year follow-up after TKA (VEGA Knee System). For clinical assessment, range of motion (ROM), Knee Injury and Osteoarthritis Outcome Score (KOOS), and Western Ontario and McMaster University Osteoarthritis Index (WOMAC) were used. For radiologic assessment, hip-knee-ankle angle, component position, and the existence of radiolucent lines and loosening were used. Survival analysis was conducted using the Kaplan-Meier method. The mean follow-up period was 9.8 years. The mean ROM increased from 124.4° to 131.4° at the final follow-up. The WOMAC score decreased from 38.5 to 17.4 at the final follow-up (p < 0.001). All 5 subscales of the KOOS improved at the final follow-up (all subscales, p < 0.001). Revision TKA was performed in 10 cases (4.3%), which included 9 cases of aseptic loosing and 1 case of periprostatic joint infection. Of the 9 aseptic loosening cases (3.9%), 8 cases (3.4%) were loosening of the femoral component and 1 case (0.4%) was loosening of the tibial component. When revision for any reason was considered an endpoint, the 10-year survivorship was 96.2% (95% confidence interval [CI], 93.9%-98.5%). On the other hand, when revision for aseptic loosening was considered the endpoint, the 10-year survivorship was 96.6% (95% CI, 94.4%-98.8%). The Vega Knee System provided good clinical results in the long-term follow-up period. Although the VEGA Knee System showed acceptable implant survivorship, loosening of the femoral component occurred in about 3.4% of the patients. For more accurate evaluation of the survivorship of high-flexion design TKA with a short posterior flange, it is necessary to conduct more long-term follow-up studies targeting diverse races, especially Asians who frequently perform high-flexion activities.

Do High-Flexion Total Knee Arthroplasty Have More Adverse Events™

Introduction: High-flexion knee prosthesis was proposed to result in better outcomes after knee arthroplasty. However, latest meta-analysis revealed that this implant indeed only produced better range of motion (ROM) and no benefits in other functional outcomes, including weight-bearing flexion. Moreover, recent studies suggested that more complications occurred in high-flexion total knee arthroplasty (TKA) instead. Objectives: This study focuses on the adverse events of high-flexion TKA compared to standard TKA in mid to long term of follow-up. Methods: Systematic search was done in online databases, i.e. Pubmed, ScienceDirect, ClinicalKey. We only included studies with a minimum follow-up duration of 5 years, expecting that this mid to long term follow-up could provide a better picture of the outcomes. Results: Seven studies were included in the final quantitative analyses, involving a total of 2,693 knees in high-flexion TKA and 3,892 knees in standard TKA. High-flexion TKA significantly had higher revision surgery compared to standard TKA (p = 0.03), 41(1.52%) and 53 (1,36%) knees, respectively. Loosening was not statistically different between those groups. Generally, radiolucent line was also more frequently observed in high-flex TKA (p = 0.01), 7.43% V 3.83% at femoral side and 5.69% V 4.41% at tibial side. Although infection and instability were higher in high-flexion knee, only a few studies found the occurrence of these parameters. Four studies evaluated the incidence of osteolysis and none was found in both groups. Conclusion: Considering that high-flexion TKA may only yield on better ROM but carry a bigger risk of adverse events, one has to cautiously weighing up the benefits and risks when planning of delivering a high-flexion TKA.

Early Femoral Failure in Two Patients Undergoing Downsizing of the Femoral Component During High-Flexion Total Knee Arthroplasty

Introduction and Importance: High-flexion prostheses can be associated with a greater risk of early aseptic loosening of the femoral component than standard prosthesis.

A review on flexion angle in high-flexion total knee arthroplasty for indonesian’s need

Total Knee Arthroplasty (TKA) proposed as an alternative treatment for damaged knee joints of humans is reviewed. The commercial application of TKA can help patients to improve their daily normal activities. Here the high-flex type total knee arthroplasty (High-Flex TKA) is typically designed for the patient’s convenience on which the greater range of motion can be adjusted for extreme activities such as Seiza and Muslim praying. However, the present High-Flex TKAs have not fulfilled the needs of Indonesians for religious activities with a flexion angle of 150°–165°. Therefore, this review aims to examine the flexion range of High-Flex TKAs proposed for the needs of Indonesians. This study is a narrative review, all studies published and reviewed are related to the range of flexion angles on the use of products from many manufacturers and various types that have been used by patients, as well as the development of a CAD-based TKA design. It was proposed in the present study that the flexion angle on High-Flex TKAs may be optimized by thickening the posterior femoral condyle, creating a medial pivot system, and applying a single radius system on the femoral component. Whereas, the tibial insert component could be designed by setting up the posterior tibial slope, and creating a post-cam stabilizer mechanism. Many knowledge gaps related to the population of research objects, lack of research on extreme angles, development of TKA components, are discussed. Further needs of extensive research on TKA in Mongoloid races are anticipated to be introduced for extreme angles and most comprehensive product development for optimization of the flexion angle.

Early Results of Bone-Conserving High Flexion Posterior-Stabilized Total Knee System in Indian Population.

A number of total knee arthroplasty (TKA) systems are used across a variety of markets in which outcome will be influenced by patient factors, surgical technique and implant characteristics. The aim of the current study was to report the early functional results of a primary TKA system in support of the component design characteristics adapted for achieving increased functional expectations of the patients. A prospective, continuous series of 304 primary posterior-stabilized (PS) TKAs were performed in 208 patients by a single surgeon. Inclusion criterion was patients undergoing primary TKA with Freedom Total Knee system and willing to participate in the study. Exclusion criteria were patients undergoing revision TKA, patients not willing to participate and patients who were lost to follow-up. Patients were clinically and radiologically assessed for a minimum of 5 years post-operatively. Oxford Knee score (OKS) and range of motion (ROM) were assessed for the entire study population and by gender. There were no patients who were lost to follow-up. Two patients (Two knees) required incision and secondary suturing for superficial skin wound complication. At minimum 5-year follow-up, there was no radiographic evidence of component loosening/failure. Clinical evaluation at 5 years post-operatively showed statistically significant increase in the OKS and ROM as compared to pre-operative values (OKS pre-operative 19.27 ± 1.86, post-operative 38.76 ± 1.5, p value < 0.001, ROM pre-operative 94.57 ± 3.49, post-operative 127.69 ± 3.65, p value < 0.001). There was no statistically significant difference in the clinical outcome between male and female genders as well as between unilateral and bilateral TKA. The study showed encouraging early results for the bone-conserving high flexion TKA system in 208 patients at minimum 5-year follow-up. The adapted design characteristics for improved functional expectations are confirmed in this reported Indian population study group cohort. Further continued evaluation is warranted for this primary TKA system across Indian and other ethnic population.

Long-term survivorship of total knee arthroplasty with a single-radius, high-flexion posterior stabilized prosthesis

BackgroundThe purpose of this study was to determine functional outcomes, implant survival rate, and complications of a single-radius, high-flexion posterior stabilized (PS) total knee prosthesis at a minimum follow up of 10 years for a consecutive series. MethodsThis retrospective observational study included 395 consecutive patients who underwent 585 single-radius, PS total knee arthroplasties (TKAs) between January 2009 and December 2009. Their functional outcomes, implant survival rates, radiological findings, and complications were evaluated. ResultsAt a mean follow up of 11.2 years (range, 10.6–11.8 years), 395 (80.8%) patients were available for review. At final follow up, preoperative Knee Society knee scores were improved from 37.3 to 80.1 (P < 0.05) and function scores were improved from 35.7 to 80.5 points (P < 0.05). Sixteen knees (2.7%) in 15 patients required revision surgery due to 11 septic loosening (1.9%) and five aseptic loosening events (0.8%). Cumulative survival for the prosthesis was 97.3% for any cause at 10 years. A total of 34 radiolucent lines (5.8%) were detected an average of 2.4 years following surgery and radiological assessment did not reveal any evidence of component migration at final follow up. ConclusionsSingle-radius, high-flexion PS TKA showed good long-term survival rates and clinical outcomes. Further study is required to determine whether limited radiolucency findings at the tibial component–tibial plateau could progress to or result in the loosening of components.

No difference of survival between cruciate retaining and substitution designs in high flexion total knee arthroplasty

The aim of this study was to compare the long-term implant survival and outcomes in patients with high-flexion cruciate-retaining (CR) or high-flexion posterior cruciate-substituting (PS) knee implants. A total of 253 knees (CR group: 159 vs. PS group: 94) were available for examination over a mean follow-up of 10 years. Clinical outcomes were assessed including the Hospital for Special Surgery score, Knee Society score and Western Ontario and McMaster Universities Osteoarthritis Index score at the final follow-up. Radiologic measurements were also assessed including the hip-knee-ankle angle and radiolucent lines according to the KSS system at the final follow-up. The survival rate was analyzed using the Kaplan–Meier method. At the final follow-up, the mean total HSS scores were similar between the two groups (p = 0.970). The mean hip-knee-ankle angle at the final follow-up was similar between groups (p = 0.601). The 10- and 15-year survival rates were 95.4% and 93.3% in the CR group and 92.7% and 90.9% in the PS group, respectively, with no significant difference. Similar clinical and radiographic outcomes could be achieved with both the high-flexion CR and high-flexion PS total knee designs without a difference in survival rate after a 10-year follow-up.

20-Year Minimum Outcomes and Survival Rate of High-Flexion Versus Standard Total Knee Arthroplasty

BackgroundThere are conflicting reports of early and mid-term results of the high-flexion total knee arthroplasties (TKAs). The purpose of the present long-term follow-up study was to determine the long-term (minimum 20 years) clinical and radiographic and CT scan results, and the survival rates of high-flexion versus standard TKAs. MethodsNinety-five patients (190 knees) were included (mean age, 65 ± 6.5 years). The mean follow-up was 20.3 years (range, 20 to 20.6 years). ResultsRevision of the TKA was performed in 5 knees (5.2%) with high-flexion TKA and in 3 knees (3.2%) with standard TKA. The rate of survival at 20 years was 94.8% (95% CI, 91%-98%) in the high-flexion TKA group and 96.8% (95% CI, 92%-100%) in the standard TKA group with reoperation for any reason. No knee had osteolysis in either group. ConclusionsAt this length of follow-up, high-flexion TKA has comparable outcomes and survivorship to standard TKA.

Is high flexion total knee arthroplasty a rewarding procedure? An updated meta-analysis of prospective randomized controlled trials.

The aim of this study is to provide an updated meta-analysis comparing the benefits and clinical outcomes between high flexion (HF)-TKA and standard (S)-TKA. A detailed database analysis was carried out using Web of Science, PubMed, EMBASE, Cochrane Library, MEDLINE and Clinicaltrial.gov, to identify eligible studies. The meta-analysis and sensitivity analysis were performed using Review Manager 5.3 software and STATA 12.0. Twenty-two randomized control trials (RCTs), including 2841 patients and 4268 knees, were eligible for the meta-analysis. The pooled results of subgroup analysis reveal that there was significant difference between HF-TKA and S-TKA in each subgroup in terms of postoperative ROM, with a higher degree of knee flexion for HF-TKA than S-TKA. However, no statistical difference was identified between HF-TKA and S-TKA in other clinical outcomes including various functional scores and complications. On the basis of this meta-analysis, we can recommended HF-TKA as an alternative choice to S-TKA for patients requiring higher knee flexion in their daily activities.

Adverse Local Tissue Reactions in Total Hip Arthroplasty: Who, When, and How to Revise

Adverse local tissue reaction (ALTR) has initially been described as a complication in metal-on-metal total hip arthroplasty (THA) [ 1 Kwon Y.-M. Glyn-Jones S. Simpson D.J. Kamali A. McLardy-Smith P. Gill H.S. et al. Analysis of wear of retrieved metal-on-metal hip resurfacing implants revised due to pseudotumours. J Bone Joint Surg Br. 2010; 92: 356-361https://doi.org/10.1302/0301-620X.92B3.23281 Crossref PubMed Scopus (185) Google Scholar , 2 Kwon Y.-M. Fehring T.K. Lombardi A.V. Barnes C.L. Cabanela M.E. Jacobs J.J. Risk stratification algorithm for management of patients with dual modular taper total hip arthroplasty: consensus statement of the American Association of Hip and Knee Surgeons, the American Academy of Orthopaedic Surgeons and the Hip Society. J Arthroplasty. 2014; 29: 2060-2064https://doi.org/10.1016/j.arth.2014.07.029 Abstract Full Text Full Text PDF PubMed Scopus (64) Google Scholar , 3 Liow M.H.L. Kwon Y.-M. Metal-on-metal total hip arthroplasty: risk factors for pseudotumours and clinical systematic evaluation. Int Orthop. 2017; 41: 885-892https://doi.org/10.1007/s00264-016-3305-1 Crossref PubMed Scopus (37) Google Scholar , 4 Kwon Y.-M. Cross-sectional imaging in evaluation of soft tissue reactions secondary to metal debris. J Arthroplasty. 2014; 29: 653-656https://doi.org/10.1016/j.arth.2014.02.007 Abstract Full Text Full Text PDF PubMed Scopus (20) Google Scholar , 5 MacDonald S.J. Brodner W. Jacobs J.J. A consensus paper on metal ions in metal-on-metal hip arthroplasties. J Arthroplasty. 2004; 19: 12-16https://doi.org/10.1016/j.arth.2004.09.009 Abstract Full Text Full Text PDF PubMed Scopus (131) Google Scholar ]. However, there have recently been increasing concerns regarding the occurrence of ALTR in metal-on-polyethylene THA due to corrosion at the head-neck taper junction in a process described as mechanically assisted crevice corrosion [ [6] Jacobs J.J. Gilbert J.L. Urban R.M. Corrosion of metal orthopaedic implants. J Bone Joint Surg Am. 1998; 80: 268-282https://doi.org/10.2106/00004623-199802000-00015 Crossref PubMed Scopus (743) Google Scholar ]. The generation of biologically active, nanometer-sized metal particles and metal ions from the arthroplasty bearing surfaces and taper junctions has been associated with the occurrence of localized, adverse periprosthetic soft tissue response, which has been recently recognized as an important emerging mode of failure in THA patients [ 7 Liow M.H.L. Urish K.L. Preffer F.I. Nielson G.P. Kwon Y.-M. Metal ion levels are not correlated with histopathology of adverse local tissue reactions in taper corrosion of total hip arthroplasty. J Arthroplasty. 2016; 31: 1797-1802https://doi.org/10.1016/j.arth.2016.01.041 Abstract Full Text Full Text PDF PubMed Scopus (28) Google Scholar , 8 Kwon Y.-M. MacAuliffe J. Arauz P.G. Peng Y. Sensitivity and specificity of metal ion level in predicting adverse local tissue reactions due to head-neck taper corrosion in primary metal-on-polyethylene total hip arthroplasty. J Arthroplasty. 2018; 33: 3025-3029https://doi.org/10.1016/j.arth.2018.04.007 Abstract Full Text Full Text PDF PubMed Scopus (30) Google Scholar , 9 Cooper H.J. Urban R.M. Wixson R.L. Meneghini R.M. Jacobs J.J. Adverse local tissue reaction arising from corrosion at the femoral neck-body junction in a dual-taper stem with a cobalt-chromium modular neck. J Bone Joint Surg Am. 2013; 95: 865-872https://doi.org/10.2106/JBJS.L.01042 Crossref PubMed Scopus (296) Google Scholar , 10 Vendittoli P.-A. Roy A. Mottard S. Girard J. Lusignan D. Lavigne M. Metal ion release from bearing wear and corrosion with 28 mm and large-diameter metal-on-metal bearing articulations: a follow-up study. J Bone Joint Surg Br. 2010; 92: 12-19https://doi.org/10.1302/0301-620X.92B1.22226 Crossref PubMed Scopus (100) Google Scholar , 11 Seon J.-K. Park J.-K. Shin Y.-J. Seo H.-Y. Lee K.-B. Song E.-K. Comparisons of kinematics and range of motion in high-flexion total knee arthroplasty: cruciate retaining vs. substituting designs. Knee Surg Sports Traumatol Arthrosc. 2011; 19: 2016-2022https://doi.org/10.1007/s00167-011-1434-z Crossref PubMed Scopus (51) Google Scholar ]. At the 2019 Annual Meeting of American Association of Hip and Knee Surgeons, the symposium on ALTRs with particular focus on “who, when, and how to revise” patients with ALTR was presented. The objectives of this symposium were to summarize clinical challenges in optimizing patient evaluation and revision surgery outcome. Specifically, the symposium presentations highlighted that there is a spectrum of clinical presentations of ALTRs due to taper corrosion and metal bearing surface wear, reflecting a complex interplay of implant, surgical, and patient factors. The current state of knowledge on the importance of various taper material combinations and taper design geometry on taper corrosion is evolving. A systematic risk stratification approach based on currently available data is critical in optimizing evaluation and revision surgery indications. The utility and limitations of specialized diagnostic tests including metal ion levels and cross-sectional imaging studies such as metal artifact reduction sequence magnetic resonance imaging in the clinical decision-making process is important in evaluation of these patients. Furthermore, optimizing revision surgery outcome for ALTRs involves careful preoperative planning, implant selection, and surgical techniques to overcome challenges associated with soft tissue necrosis.

Comparison of Modular Conventional and High-Flexion Posterior-Stabilized Total Knee Arthroplasties in the Same Patients at a Mean Follow-Up of 15 Years

BackgroundAs previous studies are limited to short-term clinical data on conventional and high-flexion total knee arthroplasties (TKAs), long-term clinical data on these TKAs remain unclear. Therefore, we evaluated long-term functional outcome, range of knee motion, revision rate, implant survival, and the prevalence of osteolysis after conventional and high-flexion TKAs in the same patients. MethodsThe authors evaluated a cohort of 1206 patients with a mean age of 65.3 ± 7 years (range: 22-70) who underwent bilateral simultaneous sequential TKAs. One knee received a conventional TKA and the other received a high-flexion TKA. The mean duration of follow-up was 15.6 years (range: 14-17). ResultsNo significant differences were found between the 2 groups at the latest follow-up with respect to Knee Society score (93 vs 92 points, P = .765), pain score (45 vs 44 points, P = .641), range of knee motion (125° vs 126°, P = .712), and radiographic and computed tomography scan results. Furthermore, no significant revision rate differences were found between the 2 groups (1.3% for conventional TKA vs 1.6% for high-flexion TKA; P = .137). There was no osteolysis recorded in either group. The rate of survivorship free of implant revision or aseptic loosening was 98.7% (95% CI = 91-100) for conventional TKA and 98.4% (95% CI = 91-100) for high-flexion TKA at 17 years. ConclusionAt the latest follow-up, we were not able to demonstrate any significant difference between conventional and high-flexion TKAs with respect to functional outcome scores, range of knee motion, revision rate, implant survival, and prevalence of osteolysis.

Fulfillment of expectations influence patient satisfaction 5years after total knee arthroplasty.

Constant efforts have been made to improve prosthesis design in total knee arthroplasty (TKA), but a significant number of patients remain dissatisfied postoperatively. Besides poor improvement in pain or function, poor fulfillment of patients expectations were identified as contributing factors. Purpose of the study was to assess fulfillment of patients' expectations and satisfaction with TKA 5years after surgery. A total of 103 patients from a prospective randomised study of a high-flexion or standard TKA implant were investigated 5years after surgery and patient-reported outcomes (PRO), fulfillment of expectations and satisfaction with the result of the surgery were obtained. There were no differences in PROs, fulfillment of expectations and satisfaction between both implant designs. In total, the patients had high expectations preoperatively, mainly related to pain relief and functional abilities. A total of 89.4% of these expectations were fulfilled. No re-interventions (p < 0.001) and male gender (p = 0.017) were the most important predictors of higher fulfillment of expectations. Satisfaction scored highly at 8.2 out of 10 and most patients (93.2%) would undergo the surgery again. Higher Knee Score (p = 0.012) and fulfillment of expectations (p = 0.002) were correlated with higher satisfaction. Five years after surgery fulfillment of expectations and satisfaction were high regardless of implant design and did significantly influence patient satisfaction. Surgeons should be aware of the importance of patients' expectations and their influence on satisfaction after TKA. Therefore, the probability of fulfillment should be discussed during shared decision making for TKA. I.

The Long-Term Results of Simultaneous High-Flexion Mobile-Bearing and Fixed-Bearing Total Knee Arthroplasties Performed in the Same Patients

BackgroundOur study determined the long-term clinical, radiographic, and computed tomography scanning results of high-flexion mobile-bearing and fixed-bearing total knee arthroplasties (TKAs) in the same younger patients. In addition, the survivorship and complication rates of both groups were evaluated. MethodsBilateral simultaneous sequential TKAs were performed in 164 patients (328 knees). There were 142 women and 22 men with a mean age of 63 ± 9 years (range 41-65), who received a high-flexion mobile-bearing prosthesis in one knee and a high-flexion fixed-bearing prosthesis in the other. The mean follow-up was 16.9 years (range 15-18). ResultsAt the latest follow-up, the mean Knee Society knee scores (94 ± 8 vs 95 ± 9 points, P = .7), Western Ontario and McMaster Universities Osteoarthritis Index (20 ± 11 vs 20 ± 11 points, P = 1.0), range of knee motion (125° ± 10° vs 127° ± 9°, P = .8), and University of California, Los Angeles activity scores (7.8 vs 7.8 points, P = 1.0) were below the level of clinical significance between the 2 groups. Survival rate of high-flexion mobile-bearing TKA was 98.2% and that of high-flexion fixed-bearing TKA was 97% at 16 years. No osteolysis was identified in either group. ConclusionAfter a minimum duration of follow-up of 13 years, we found no significant difference between these 2 groups with regard to functional outcome, knee motion, prevalence of osteolysis, or survivorship. This study does not clearly direct the surgeon toward either arm of treatment. Longer term follow-up is needed to prove the superiority of one type of implant over the other one.

Cementing technique affects the rate of femoral component loosening after high flexion total knee arthroplasty

BackgroundThe purpose of this study was to determine the effects of different cementing techniques on the rate of early femoral loosening of high-flexion total knee arthroplasties (TKAs). MethodsA total of 734 knees from 486 patients treated with high-flexion design TKA between July 2001 and July 2010 were divided into two groups based on the cementing technique used. For 403 knees (group N), cement was applied onto the distal and anterior cut surfaces of the femur and the posterior flanges of the femoral component without pressurization. For 331 knees (group P), cement was applied onto distal and anterior femoral cut surfaces with digital pressurization and whole cement surfaces of the femoral component. Two groups were subjected to clinical and radiological evaluation with a minimum five year follow-up period. Cox proportional hazards model with revision surgery of the prosthesis or radiological loosening as an endpoint was used to evaluate the effect of the cementing technique and other covariates. ResultsThe pressurizing and bi-surface cementing technique resulted in significant reduction in femoral radiological loosening incidence compared to that without pressurization (0.3% vs. 2.5%, P=0.015) and revision rate for aseptic causes (0.9% vs. 3.2%, P=0.032). Cox proportional hazard regression analysis revealed a significant difference in component survival rate between the two groups if femoral radiological loosening was considered as failure (hazard ratio, 4.229, 95% confidence interval (CI): 1.256–14.243, P=0.020). ConclusionPressurizing and bi-surface cementation can reduce the occurrence rate of early loosening around the femoral component in high-flexion TKAs.

Comparison of High-Flexion Fixed-Bearing and High-Flexion Mobile-Bearing Total Knee Arthroplasties—A Prospective Randomized Study

BackgroundThere is none, to our knowledge, about comparison of high-flexion fixed-bearing and high-flexion mobile-bearing total knee arthroplasties (TKAs) in the same patients. The purpose of this study was to determine whether clinical results; radiographic and computed tomographic scan results; and the survival rate of a high-flexion mobile-bearing TKA is better than that of a high-flexion fixed-bearing TKA. MethodsThe present study consisted of 92 patients (184 knees) who underwent same-day bilateral TKA. Of those, 17 were men and 75 were women. The mean age at the time of index arthroplasty was 61.5 ± 8.3 years (range 52-65 years). The mean body mass index was 26.2 ± 3.3 kg/m2 (range 23-34 kg/m2). The mean follow-up was 11.2 years (range 10-12 years). ResultsThe Knee Society knee scores (93 vs 92 points; P = .531) and function scores (80 vs 80 points; P = 1.000), WOMAC scores (14 vs 15 points; P = .972), and UCLA activity scores (6 vs 6 points; P = 1.000) were not different between the 2 groups at 12 years follow-up. There were no differences in any radiographic and CT scan parameters between the 2 groups. Kaplan-Meier survivorship of the TKA component was 98% (95% confidence interval, 93-100) in the high-flexion fixed-bearing TKA group and 99% (95% confidence interval, 94-100) in the high-flexion mobile-bearing TKA group 12 years after the operation. ConclusionWe found no benefit to mobile-bearing TKA in terms of pain, function, radiographic and CT scan results, and survivorship. Longer-term follow-up is necessary to prove the benefit of the high-flexion mobile-bearing TKA over the high-flexion fixed-bearing TKA.

Kneeling and standing up from a chair as performance-based tests to evaluate knee function in the high-flexion range: a randomized controlled trial comparing a conventional and a high-flexion TKA design

BackgroundWe compared the functional outcome between conventional and high-flexion total knee arthroplasty (TKA) using kneeling and sit-to-stand tests at 1 year post-operative. In addition, the patient’s daily functioning, pain and satisfaction were quantified using questionnaires.MethodsWe randomly assigned 56 patients to receive either a conventional or a high-flexion TKA. Primary outcomes were maximum flexion angle and maximum thigh-calf contact measured during kneeling at 1 year post operatively. Secondary outcomes were the angular knee velocity and ground reaction force ratio measured during sit-to-stand performance tests, and questionnaires.ResultsAt one year post-operative, maximum knee flexion during kneeling was higher for the high-flexion TKA group (median 128.02° (range 108–146)) compared to the conventional TKA group (119.13° (range 72–135)) (p = 0.03). Maximum thigh-calf contact force was higher for the high flexion TKA group (median 17.82 N (range 2.98–114.64)) compared to the conventional TKA group (median 9.37 N (range 0.33–46.58))(p = 0.04). The sit-to-stand tests showed a significantly higher angular knee velocity in the conventional TKA group (12.12 rad/s (95%CI 0.34–23.91); p = 0.04). There were no significant differences between groups in ground reaction force ratios and patient-reported outcome scores.ConclusionAlthough no differences were found in patient-reported outcome scores, differences in performance-based tests were clearly apparent. Standing up from a chair at 90° of knee flexion appeared to be easier for the conventional group. The kneeling test revealed significantly higher weight-bearing knee flexion for the high-flex group. Hence, if kneeling is an important activity for a patient a high-flex design may be recommendable.Trial registrationThe study was retrospectively registered in ClinicalTrials.gov under identifier NCT00899041 (date of registration: May 11, 2009).

In vitro and in vivo kinematics of total knee arthroplasty—a review of the research at the Orthopaedic Bioengineering Laboratory of the Massachusetts General Hospital (MGH)

Quantitative data of total knee arthroplasty (TKA) kinematics is vital for understanding component failure and to provide guidelines for improvement of the component design. Our lab started studying TKA kinematics in 1998. First, we developed an in vitro robotic experimental setup to test knee kinematics after TKA surgery under various simulated physiological loading conditions. Second, we developed a dual fluoroscopic imaging system (DFIS) to analyze the in vivo knee kinematics after TKA surgery during functional activities. Using these in vitro and in vivo approaches, we have extensively investigated the kinematics of typical posterior cruciate retaining (CR) and posterior substituting (PS) TKAs. Analyses included six degrees-of-freedom (DOF) tibiofemoral joint kinematics, tibiofemoral articular contact locations, posterior cruciate ligament (PCL) function in CR TKAs and cam-post contact in PS TKAs. In addition we have studied the biomechanical factors that may affect flexion capabilities of the knee by comparing the biomechanics of conventional, high-flexion TKA designs with normal knees and knees with osteoarthritis (OA). In this review, we will briefly describe the in vitro and in vivo testing systems developed at our lab for TKA kinematics analyses followed by a summary of our research results on various TKA components.

Midterm outcomes of high-flexion total knee arthroplasty on Japanese lifestyle

ObjectiveTo evaluate the clinical outcomes after total knee arthroplasty (TKA) using the Genesis II posterior stabilized prosthesis with a high-flex insert during the mid-term follow-up and to assess its effect on the Japanese lifestyle. Materials and methodsFifty-three consecutive patients (8 men and 45 women) underwent primary TKA. The mean follow-up time was 76 months (5–9 years). Clinical results were assessed with the Japanese Orthopedic Association osteoarthritis knee rating score (JOA knee score), range of motion, and lifestyle changes. ResultsThe postoperative JOA knee score improved significantly compared to the preoperative JOA knee score. The mean preoperative flexion range improved from 112° to 123° postoperatively (p < 0.05). Additionally, our findings showed that 39% of patients enjoyed a floor-sitting life preoperatively, but only 30% of patients enjoyed floor-sitting life postoperatively. ConclusionThe postoperative range of knee motion and JOA knee score improved after TKA using the Genesis II posterior stabilized prosthesis with a high-flex insert, but the number of patients who enjoyed floor-sitting life decreased from 39% to 30% because of feelings of fear and discomfort.Level of Evidence: Level IV, Therapeutic study

Minimum 5-year follow-up results and functional outcome of rotating-platform high-flexion total knee arthroplasty: A prospective study of 701 knees.

BackgroundTo evaluate the midterm clinical outcome, functional outcome, associated complications, and survivorship of high-flexion posterior-stabilized rotating-platform total knee arthroplasty.MethodsWe prospectively analyzed 701 knees in 501 patients, who underwent total knee arthroplasty using high-flexion posterior-stabilized rotating-platform prosthesis. Patients were assessed preoperatively and postoperatively for their ability to kneel, do full squats, do half squats, and sit cross-legged by using a patient-administered questionnaire.ResultsSignificant improvement was seen in patient-reported outcomes at the mean follow-up of 5.5 (range, 5-7) years. Mean flexion achieved postoperatively was 135° (range, 120°-150°) from a mean preoperative flexion of 108.8° (range, 90°-120°). Ninety-five percent of patients were able to sit cross-legged, 90% were able to kneel, 70% were able to perform a half squat, and 20% were able to perform a full squat.ConclusionsPosterior-stabilized, rotating-platform, high-flexion design provides good postoperative flexion, functional outcome, and good midterm survivorship.

Two- to Four-Year Follow-up Results of Total Knee Arthroplasty Using a New High-Flexion Prosthesis.

PurposeThe purpose of this study was to evaluate minimum 2-year follow-up results of total knee arthroplasty (TKA) performed using a new high-flexion prosthesis design (LOSPA).Materials and MethodsThe 2- to 4-year results of 191 consecutive TKAs (177 patients) with the LOSPA posterior-stabilized prosthesis were evaluated. The patients were assessed clinically and radiographically using the Knee Society scoring system (KSS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).ResultsThe mean range of motion (ROM) increased significantly from 117.4° (range, 75° to 140°) preoperatively to 126.7° (range, 80° to 144°) postoperatively (p<0.001). The mean KSS and WOMAC scores improved significantly from 121.4 (range, 42 to 185) and 56.1 (range, 23 to 88) preoperatively to 174.0 (range, 130 to 200) and 16.4 (range, 0 to 85) postoperatively, respectively (both, p<0.001). One knee required revision for deep infection. No knee had aseptic loosening or osteolysis. Radiolucent lines were noted in 15 knees (7.9%).ConclusionsThe new high-flexion total knee prosthesis resulted in no early aseptic loosening of the component and improved postoperative ROM comparable to other high-flexion TKA prostheses at 2- to 4-year follow-ups.