Tibial Slope Is Not Associated With Implant Migration Following Cemented Total Knee Arthroplasty With a Single Implant Design.

BACKGROUND: The influence of tibial slope on tibial component migration following total knee arthroplasty has not been widely studied, although excessive posterior slope has been implicated in some failures. As implant micromotion measured with radiostereometric analysis can indicate successful fixation, the purpose of this study was to determine the associations between tibial slope, tibial component migration, and inducible displacement. METHODS: Radiostereometric analyses at 6 visits over 2 years quantified implant migration for 200 cemented total knee arthroplasties. Longitudinal data analysis examined the influence of postoperative tibial slope on implant migration (overall maximum total point motion (MTPM) migration and anterior-posterior tilt migration), accounting for age, sex, and body mass index. The correlations of tibial slope with 1-year migration, continuous migration, and inducible displacements were also examined. Additionally, the amount of change in slope was compared to migration. RESULTS: The mean posterior tibial slope was 8.0° (standard deviation [SD] 3.8°) preoperatively and 3.8° (SD 3.1°) postoperatively, with a mean reduction in slope of 4.2° (SD 4.7°). Postoperative tibial slope (range 14.0° posterior slope to 3.4° anterior slope) was not associated with longitudinal overall migration (P = .671) or anterior-posterior tilt migration (P = .704). There was no association between postoperative tibial slope and migration at 1 year postoperatively (P = .441 for MTPM migration, P = .570 for tilt migration), change in migration from 1 to 2 years (P = .951), or inducible displacement (P = .970 MTPM, P = .730 tilt). The amount of change in tibial slope was also not associated with migration or inducible displacement. CONCLUSIONS: Residual and change in postoperative tibial slope were not associated with implant migration into tilt or overall migration, or inducible displacement for a single implant design. These findings support positioning tibial implants in a range of slopes, which may support patient-specific approaches to implant alignment.

Patient acceptable symptom state (PASS): thresholds for the EQ-5D-5L and Oxford hip and knee scores for patients with total hip and knee replacement.

PURPOSE: To define patient acceptable symptom state (PASS) cut-off values for the EQ-5D-5L and Oxford hip (OHS) and knee (OKS) scores 6 and 12 months after total hip (THR) or knee (TKR) replacement. To compare PASS cut-off values for the EQ-5D-5L scored using: (1) the Canadian value set, (2) the crosswalk value set, and (3) the equal weighted Level Sum Score (LSS). METHODS: We mailed questionnaires to consecutive patients following surgeon referral for primary THR or TKR and at 6 and 12 months post-surgery. Patient reported outcome measures (PROMs) were the EQ-5D-5L, the OHS, and OKS. We assessed PASS cut-off values for PROMs using percentile and ROC methods, with the Youden Index. RESULTS: Five hundred forty-two surgical patients (mean age, 64 years, 57% female, 49% THR) completed baseline and 12-month questionnaires. 89% of THR and 81% of TKR patients rated PASS as acceptable at 12 months. PASS cut-off values for THR for the EQ-5D-5L (Canadian) were 0.85 (percentile) and 0.84 (Youden) at 12 months. Cut-off values were similar for the LSS (0.85 and 0.85) and lower for the crosswalk value set (0.74 and 0.73), respectively. EQ-5D-5L cut-off values for TKR were Canadian, 0.77 (Percentile) and 0.78 (Youden), LSS, 0.75 and 0.80, and crosswalk, 0.67 and 0.74, respectively. Cut-off values 6 and 12 months post-surgery ranged from 38 to 39 for the OHS, and 28 to 36 for the OKS (range 0 worst to 48 best). CONCLUSION: PASS cut-off values for the EQ-5D-5L and Oxford scores varied, not only between methods and timing of assessment, but also by different EQ-5D-5L value sets, which vary between countries. Because of this variation, PASS cut-off values are not necessarily generalizable to other populations of TJR patients. We advise caution in interpreting PROMs when using EQ-5D-5L PASS cut-off values developed in different countries. A standardization of methods is needed before published cut-off values can be used with confidence in other populations.

Mid-Term Performance of the First Mass-Produced Three-Dimensional Printed Cementless Tibia in the United States as Reported in the American Joint Replacement Registry.

BACKGROUND: Cementless tibial components have shown improvements in clinical performance compared to predicate designs, though evidence supporting mid-term performance and fixation is scarce. The purpose of this study is to determine the mid-term survivorships, revision rates, and reasons why 3-dimensional printed cementless tibial baseplates (3DTKAs) failed compared to other cementless as well as cemented tibial baseplates reported from the American Joint Replacement Registry (AJRR) data. METHODS: All primary total knee arthroplasty (TKA) cases performed in patients 65 years of age or older within the AJRR from January 2, 2012 through June 30, 2020 were queried. A total of 28,631 3DTKAs were identified from 428 institutions. These were compared to all other "aggregated cementless tibia" (n = 7,577) and "aggregated cemented tibia" (n = 550,133) cases. Centers for Medicare & Medicaid Services data over the same time period were merged with AJRR data to determine survivorship and patient-timed incident revision rates per 1,000 years. Failure reasons were tracked during this study period. RESULTS: At 60 months, Kaplan-Meier implant survivorship was 98.9% (CI 98.7-99.0), 98.3% (CI 97.9-98.6), and 98.4% (CI 98.4-98.5) in the 3DTKA, aggregate cementless, and cemented knee cohorts, respectively (P < .0001). Patient-timed incident revision rates were 3.11 (CI 2.75-3.53), 3.99 (CI 3.34-4.76), and 3.35 (CI 3.28-3.42) for those cohorts, which corresponds to a revision rate of 0.31%, 0.40%, and 0.34% per year. CONCLUSION: In this analysis, 3DTKA had favorable survivorship and lower revision rates compared to aggregate cementless and cemented TKAs implanted from the same national database during the same time period.

Continuity of primary care and emergency department visits following knee and hip replacement surgery: a retrospective cohort study.

BACKGROUND: Continuity of primary care (CPC) improves patient well-being, but the association between CPC and surgical outcomes has not been well studied. The numbers of joint replacement procedures are expected to rise considerably in the coming years, so it is crucial to identify factors related to successful outcomes. The purpose of this study was to examine the association between CPC and emergency department (ED) visits after knee and hip replacement surgery. METHODS: Physician claims and hospital data from 2005 to 2020 in Nova Scotia were used in this retrospective study. To measure CPC, we used the Modified Modified Continuity Index (MMCI), which is the number of primary care providers adjusted for the total number of visits. The outcome was ED visits within 90 days of discharge. Logistic regression was used to test for associations between MMCI and the probability of an ED visit. RESULTS: There were 28 574 knee and 16 767 hip procedures in the data set; 13.9% (95% confidence interval [CI] 13.5%-14.3%) and 13.5% (95% CI 13.0%-14.0%) of the patients, respectively, had an ED visit within 90 days. For patients who underwent knee procedures, the mean MMCI was 0.868 (95% CI 0.867-0.870); 10.7% (95% CI 10.4 %-11.1 %) had perfect continuity of care. For patients who underwent hip procedures, the corresponding measures were 0.864 (95% CI 0.862-0.866) and 13.5% (95% CI 13.0%-14.0%). There was a statistically significant negative association between greater continuity of care and the probability of an ED visit after controlling for confounders. CONCLUSION: Having multiple primary care providers before surgery increased the likelihood of negative outcomes following knee or hip replacement surgery compared with having a single provider. Presurgical conversations should include primary care history to improve postsurgical outcomes.

6-month migration sufficient for evaluation of total knee replacements: a systematic review and meta-analysis.

BACKGROUND AND PURPOSE: This updated meta-analysis evaluates the migration pattern of the tibial component of primary total knee replacements measured with radiostereometric analysis (RSA). We aimed to evaluate whether 6-month maximum total point motion (MTPM) values could be used instead of 1-year MTPM for RSA threshold testing and to present the pooled migration patterns for different implant designs that can be used as a benchmark. PATIENTS AND METHODS: The search included all published RSA studies on migration patterns of tibial components until 2023. Study groups were classified according to their prosthesis brand, fixation, and insert (PFI). Sub-analyses were performed to compare the mean tibial component migration patterns of different implant variables, stratified according to fixation. RESULTS: 96 studies (43 new studies), including 197 study groups and 4,706 knees, were included. Most migration occurred within the first 6 postoperative months (126 study groups: mean 0.58 mm, 95% confidence interval [CI] 0.50-0.65), followed by minimal migration between 6 and 12 months (197 study groups: mean 0.04 mm, CI 0.03-0.06), irrespective of the fixation method used. Distinct migration patterns were observed among the different fixation methods. No differences were found in migration patterns among cemented components in any of the sub-group analyses conducted. For uncemented implants, trabecular metal surfaced components seemed to migrate less than porous-coated or uncoated components Conclusion: Based on the small difference between MTPM values at 6 months and 1 year, MTPM at 6 months could be used instead of MTPM at 1 year for RSA threshold testing. The pooled migration patterns can be used as benchmark for evaluation of new implants by defining fixation-specific RSA thresholds when combined with implant survival.

A low-dose biplanar X-ray imager has RSA level precision in total knee arthroplasty.

BACKGROUND AND PURPOSE: The low radiation biplanar X-ray imager (EOS imaging, Paris, France) scans patients in a weight-bearing position, provides calibrated images, and limits radiation, an asset for serial radiostereometric analysis (RSA) studies. RSA in vivo precision values have not been published for this type of imaging system, thus the goal of this study was to assess the precision of RSA in vivo utilizing a low radiation biplanar imager. PATIENTS AND METHODS: At a mean of 5 years post-surgery (range 1.4-7.5 years), 15 total knee arthroplasty (TKA) participants (mean age 67 years at the time of imaging, 12 female, 3 male) with RSA markers implanted during index surgery were scanned twice at the same visit in the EOS imager. Precision of marker-based analysis was calculated by comparing the position of the implant relative to the underlying bone between the 2 examinations. RESULTS: The 95% limit of precision was 0.11, 0.04, and 0.15 mm along the x, y, and z axes, respectively and 0.15°, 0.20°, and 0.14° around the same axes. CONCLUSION: This precision study has shown an in vivo RSA precision of ≤ 0.15 mm and ≤ 0.20°, well within published uniplanar values for conventional arthroplasty RSA, with the added benefit of weight-bearing imaging, a lower radiation dose, and without the need for a reference object during the scan.

Tibial Component Migration After Total Knee Arthroplasty With High-Viscosity Bone Cement.

BACKGROUND: High-viscosity (HV) bone cements have been formulated to offer potentially advantageous handling characteristics. However, alteration in the handling characteristics could influence implant fixation and survival. The primary objective of this study was to use radiostereometric analysis after total knee arthroplasty to assess the migration of the Triathlon tibial component fixed with HV cement (Simplex HV). METHODS: Twenty-three patients were followed for two years with radiostereometric analysis examinations at 6 visits. Migration was compared with published thresholds and with a control group from a previously published study from the same center using the same implants fixed with a medium viscosity cement. Inducible displacement was assessed, and Oxford 12 Knee Scores and satisfaction were recorded. RESULTS: Mean maximum total point motion migration reaching 0.40 mm (SD 0.16) at one year, and 0.41mm (SD 0.17) at two years, demonstrating a pattern of stable fixation, below published thresholds of acceptable migration, and not significantly different from the control group. One implant had continuous migration between 1 and 2 years but was clinically asymptomatic. Mean maximum total point motion inducible displacement measured at least one year postoperatively was 0.3 mm (SD 0.12). Mean Oxford 12 Knee Scores improved from 19 (SD 7) preoperatively to 42 (SD 8) 2 years postoperatively. CONCLUSIONS: The use of HV cement demonstrated an acceptable pattern of migration at 2 years, indicating low risk for aseptic loosening.

Early Identification of Patient Satisfaction Two Years After Total Knee Arthroplasty.

BACKGROUND: There are numerous reports of poor satisfaction after total knee arthroplasty (TKA), yet there is little known about when to use evidence-based models of care to improve patient outcomes. OBJECTIVE: This study aimed to characterize longitudinal changes in patient-reported satisfaction after TKA and to identify factors for early identification of poor satisfaction. METHODS: For a cohort of primary TKA surgeries (n = 86), patient-reported outcomes were captured one week before TKA and 6 weeks, 12 weeks, 6 months, and 1 and 2 years after TKA. "Satisfied" versus "not fully satisfied" patients were defined using a binary response (≥90 vs <90) from a 100-point scale. Wilcoxon signed-rank tests identified changes in satisfaction between follow-up times, and longitudinal analyses examined demographic and questionnaire factors associated with satisfaction. RESULTS: Improvements in satisfaction occurred within the first 6 months after TKA (P ≤ 0.01). Preoperative patient-reported outcome measures alone were not predictive of satisfaction. Key factors that improved longitudinal satisfaction included higher Oxford Knee Scores (odds ratio (OR) = 2.1, P < .001), general health (EQ-VAS, OR = 1.3, P = .03), and less visual analog scale pain (VAS; OR = 1.7, P < .001). Differences in these factors between satisfied and not fully satisfied patients were identified as early as 6 weeks after surgery. CONCLUSION: Visibly different satisfaction profiles were captured among satisfied and not fully satisfied patient responses, with differences in patient-perceived joint function, general health, and pain severity occurring as early as 6 weeks after surgery. This study provides metrics to support early identification of patients at risk of poor TKA satisfaction, enabling clinicians to apply timely targeted treatment and support interventions, with the aim of improving patient outcomes.

Quantifying Achievable Levels of Improvement in Knee Joint Biomechanics During Gait After Total Knee Arthroplasty Relative to Osteoarthritis Severity.

Total knee arthroplasty (TKA) surgery improves knee joint kinematics and kinetics during gait for most patients, but a lack of evidence exists for the level and incidence of improvement that is achieved. The objective of this study was to quantify patient-specific improvements in knee biomechanics relative to osteoarthritis (OA) severity levels. Seventy-two patients underwent 3-dimensional (3D) gait analysis before and 1 year after TKA surgery, as well as 72 asymptomatic adults and 72 with moderate knee OA. A combination of principal component analysis and discriminant analyses were used to categorize knee joint biomechanics for patients before and after surgery relative to asymptomatic, moderate, and severe OA. Post-TKA, 63% were categorized with knee biomechanics consistent with moderate OA, 29% with severe OA, and 8% asymptomatic. The magnitude and pattern of the knee adduction moment and angle (frontal plane features) were the most significant contributors in discriminating between pre-TKA and post-TKA knee biomechanics. Standard of care TKA improves knee biomechanics during gait to levels most consistent with moderate knee OA and predominately targets frontal plane features. These results provide evidence for the level of improvement in knee biomechanics that can be expected following surgery and highlight the biomechanics most targeted by surgery.

Patient expectations and satisfaction 6 and 12 months following total hip and knee replacement.

PURPOSE: To assess (1) patient expectations before total hip (THR) and knee (TKR) replacement; (2) which expectations are met and unmet 6 and 12 months post-surgery; (3) the role of unmet expectations in satisfaction. METHODS: Questionnaires were mailed to consecutive patients following surgeon referral for primary THR or TKR. Patients listed their own expectations and also completed the Hospital for Special Surgery (HSS) Expectation Survey. We used content analysis to group expectations into themes. At 6 and 12 months post-surgery, patients were given a copy of their own list of individual expectations and reassessed each one as met or unmet. We also assessed fulfilled HSS expectations and satisfaction with surgery. RESULTS: The sample of 556 patients (49% THR, 57% female) had a mean age of 64 years (SD10). The five most frequent expectation themes were pain relief, mobility, walking, physical activities, and daily activities. Of these, physical activities had the lowest percentage met 12 months post-surgery. 95% (THR) and 87% (TKR) were satisfied/very satisfied with their surgery 12 months post-surgery. Very satisfied patients had a significantly greater percentage of met expectations (96% THR; 92% TKR) than dissatisfied patients (42% THR; 12% TKR). Although most expectations listed by patients were included in the HSS surveys, some were not, particularly for TKR. From 6 to 12 months, there was a significant increase in patient satisfaction for self-care, daily activities, and met expectations for THR and pain relief, self-care, daily activities, and recreational activities for TKR. CONCLUSIONS: Expectations should be explicitly addressed before surgery, including a discussion of realistic expectations, particularly for physical activities.

Increased Mortality with the Use of Cementless Fixation for Femoral Neck Fractures: Analysis of 5883 Hip Arthroplasty Cases.

BACKGROUND: The use of cemented fixation for hip arthroplasty for femoral neck fractures has been advocated to limit the postoperative and intraoperative risk of periprosthetic fractures. However, there are concerns with the potential effects of cementing on patient mortality, particularly at the time of cementation. METHODS: This study examined the mortality rates of cemented compared to cementless hip arthroplasty fixation in a group of 5883 femoral neck fracture patients from 2001 to 2017. The data were derived from large administrative databases and census data. Confounders were identified and controlled with a multivariate analysis. The data were also stratified into 2 time frames, 2001-2008 and 2009-2017, to determine if there was an effect of more recent improvements in patient care or implant technology. RESULTS: Cemented fixation had a statistically significant reduction in mortality rates at 30, 90, and 365 days after surgery. There was no difference in mortality in 0, 1, or ≤7 days after discharge or during the admission. The mortality rate decreased but was still significantly increased with cementless fixation when the subjects were grouped from 2001 to 2008 and 2009 to 2017. CONCLUSION: Based on this evidence, the cemented fixation of hip arthroplasty should be considered for patients with femoral neck fractures.

Measuring Surgical Site Infection From Linked Administrative Data Following Hip and Knee Replacement.

BACKGROUND: Surgical site infections (SSIs) in hip and knee arthroplasty are increasing internationally. Current trends in SSI monitoring use single source administrative databases with data collection points commonly at 30 or 90 days. We hypothesize that SSI rates are being under-reported due to methodological biases. METHODS: Data from multiple administrative data sets were contrasted and compared to look at the 90-day SSI rates for hip and knee arthroplasty in a single province from 2001 to 2015. SSI rates were calculated over time by year, and the differences in infection rates between single and multiple administrative data sets were calculated as an estimate of under reporting rates of SSIs. Days until diagnosis was measured for those diagnosed with an infection within 1 year. RESULTS: Combining administrative data sets indicates that hospital-based data underestimate SSI rates by 0.44 (P < .0001) of a percentage point over all years, a clinically significant result given the overall infection rate of 2.2% over the period. Less than 50% of hip and knee arthroplasty was recorded as infected by 30 days and approximately 75% of cases were recorded as infected by 90 days. CONCLUSION: Single source administrative data sets and short follow-up periods underestimate SSI rates. Administrative data sets should be combined and a minimum follow-up period of 90 days should be used to more accurately track SSI rates in hip and knee arthroplasty.

Migration and Wear of a Dual Mobility Acetabular Construct at 3 Years Measured by Radiostereometric Analysis.

BACKGROUND: The anatomic dual mobility (ADM) acetabular component was introduced because of previously described low dislocation rates for this type of construct. The shape of the anatomic cup and the motion of polyethylene liner may have implications for acetabular cup fixation and polyethylene liner wear; therefore, the purpose of this study was to assess the migration patterns and wear rates of the ADM component using radiostereometric analysis. METHODS: Uncemented ADM acetabular components were implanted in 27 patients. Radiostereometric analysis exams were taken at 6 follow-up visits over 3 years. Proximal translation and sagittal rotation of the cup and polyethylene total wear and wear rates were calculated. Oxford 12 Hip scores and satisfaction were recorded. RESULTS: Mean proximal translation was below the 0.2 mm threshold at 2 years associated with acceptable long-term survivorship (0.16 mm [standard deviation {SD} 0.31] at 3 years). Mean sagittal rotation was 0.29 degrees (SD 1.03) and was greater in female subjects (P < .001). Following bedding-in, the annual wear rate was 0.02 mm/y, below the 0.1 mm/y threshold. There was no association between cup migration and polyethylene wear. Patient satisfaction at 3 years was 96%. Mean Oxford 12 Hip scores improved from 21 (SD 7) preoperatively to 43 (SD 7) 3 years postoperatively. CONCLUSIONS: The ADM cup demonstrated stable migration at 3 years indicating low risk for aseptic loosening. Bedding-in in the first year was followed by low annual wear rates. These finding suggest no increased risk of the dual mobility and anatomic design on fixation or wear.

Equivalent 2-year stabilization of uncemented tibial component migration despite higher early migration compared with cemented fixation: an RSA study on 360 total knee arthroplasties.

Background and purpose - Thresholds of implant migration for predicting long-term successful fixation of tibial components in total knee arthroplasty have not separated cemented and uncemented fixation. We compared implant migration of cemented and uncemented components at 1 year and as the change in migration from 1 to 2 years. Patients and methods - Implant migration of 360 tibial components measured using radiostereometric analysis was compared at 1 year and as the change in migration from 1 to 2 years in 222 cemented components (3 implant designs) and 138 uncemented components (5 implant designs). Results - 1-year maximum total point motion was lower for the cemented tibial components compared with the uncemented components (median = 0.31 mm [0.03-2.98] versus 0.63 mm [0.11-5.19] respectively, p < 0.001, mixed model). The change in migration from 1 to 2 years, however, was equivalent for cemented and uncemented components (mean [SD] 0.06 mm [0.19] and 0.07 mm [0.27] mm respectively, p = 0.6, mixed model). Interpretation - These findings suggest that current thresholds of acceptable migration at 1 year may be better optimized by considering cemented and uncemented tibial components separately as higher early migration of uncemented components was not associated with decreased stability from 1 to 2 years.

Comparing the validity and responsiveness of the EQ-5D-5L to the Oxford hip and knee scores and SF-12 in osteoarthritis patients 1 year following total joint replacement.

PURPOSE: (1) To assess responsiveness of the EQ-5D-5L compared to Oxford hip and knee scores and the SF-12 in osteoarthritis patients undergoing total hip (THR) or knee (TKR) replacement surgery; (2) to compare distribution and anchor-based methods of assessing responsiveness. METHODS: Questionnaires were mailed to consecutive patients following surgeon referral for primary THR or TKR and 1 year post-surgery. We assessed effect size (ES), standardized response mean (SRM), and standard error of measurement (SEM). Minimum important difference (MID) was the mean change in patients reporting somewhat better in hip or knee, health in general, and those who were satisfied with surgery (5-point scales). Responders were compared using MID versus 1 and 2SEM. RESULTS: The sample of 537 (50% TKR) was composed of 56% female with a mean age of 64 years (SD 10). EQ-5D-5L ES was 1.86 (THR) and 1.19 (TKR) compared to 3.00 and 2.05 for Oxford scores, respectively. MID for the EQ-5D-5L was 0.22 (THR) and 0.20 (TKR) for patients who rated their hip or knee as somewhat better. There was a wide variation in the MID and the percentage of responders, depending on the joint, method of assessment, and the outcome measure. The percent agreement of responder classification using 2SEM vs. MID ranged from 79.6 to 99.6% for the EQ-5D-5L and from 69.4 to 94.8% for the Oxford scores. CONCLUSIONS: Responsiveness of the EQ-5D-5L was acceptable in TKR and THR. Caution should be taken in interpreting responder to TJR based on only one method of assessment.

Reliability and validity of the EQ-5D-5L compared to the EQ-5D-3L in patients with osteoarthritis referred for hip and knee replacement.

PURPOSE: To assess the test-retest reliability of the EQ-5D-5L (5L) and compare the validity of the 5L and EQ-5D-3L (3L) in osteoarthritis patients referred to an orthopaedic surgeon for total joint replacement. METHODS: We mailed questionnaires to 306 consecutive patients following referral and a second questionnaire after 2 weeks to assess reliability. Questionnaires included the 5L, EQ-VAS, Short Form-12, Oxford hip and knee scores, pain VAS, and the 3L. We compared the ceiling effect, redistribution properties, convergent and discriminant validity, and discriminatory power of the 5L and 3L. RESULTS: We obtained 176 respondents (response rate 58 %), 60 % female, 64 % knee patients, mean age 65 years (SD 11), with no significant differences between responders versus non-responders. Intraclass correlation coefficients were 0.61-0.77 for the 5L dimensions and 0.87 for the 5L index. For the 3L, most patients used level 2 (some/moderate problems) for mobility (87 %), usual activities (78 %), and pain/discomfort (71 %). In comparison, 5L responses were spread out with only 52, 42, and 50 %, respectively, using the middle level. All convergent validity coefficients were stronger with the 5L (Spearman coefficients 0.51-0.75). Absolute informativity (Shannon's index) showed higher results for all dimensions of the 5L compared with the 3L (average difference 0.74). Relative informativity (Shannon's evenness index) showed an increase from the 3L to the 5L in mobility, usual activities, and pain/discomfort. CONCLUSIONS: The 5L provided stronger validity evidence than the 3L, especially for dimensions relevant to this patient population-mobility, usual activities, and pain/discomfort.

Knee joint biomechanics and neuromuscular control during gait before and after total knee arthroplasty are sex-specific.

The future of total knee arthroplasty (TKA) surgery will involve planning that incorporates more patient-specific characteristics. Despite known biological, morphological, and functional differences between men and women, there has been little investigation into knee joint biomechanical and neuromuscular differences between men and women with osteoarthritis, and none that have examined sex-specific biomechanical and neuromuscular responses to TKA surgery. The objective of this study was to examine sex-associated differences in knee kinematics, kinetics and neuromuscular patterns during gait before and after TKA. Fifty-two patients with end-stage knee OA (28 women, 24 men) underwent gait and neuromuscular analysis within the week prior to and one year after surgery. A number of sex-specific differences were identified which suggest a different manifestation of end-stage knee OA between the sexes.