Severe genu varus deformity does not affect enhanced recovery after surgery total knee arthroplasty outcomes.

INTRODUCTION: Enhanced recovery after surgery (ERAS) has been increasingly adopted in orthopaedic surgery. Although not an exclusion criterion, patients undergoing total knee arthroplasty (TKA) with preoperative severe varus deformity may be less likely to be enrolled for ERAS. This study aimed to compare the success of ERAS TKA between patients with severe preoperative varus deformities (≥ 15° varus) and the control group (< 15° varus to 14° valgus). Our secondary aim was to compare postoperative complications and functional outcomes between the two groups. MATERIALS & METHODS: 310 TKAs performed from August 2019 to February 2021 were analyzed with a follow-up of 6 months postoperatively. The primary outcome, ERAS TKA success, was defined as length of hospital stay of < 24 h. Other parameters included 30-day postoperative complications and clinical outcomes such as the original Oxford Knee Score (OKS), the Knee Society Knee (KSKS) and Function Score (KSFS), Visual Analog Scale for Pain (VAS-P), 36-Item Short-Form Health Survey (SF-36) Physical Component Summary (PCS) and SF-36 Mental Component Summary (MCS). RESULTS: There were 119 patients in the severe deformity group and 191 patients in the control group. There were no significant differences in ERAS success between the severe deformity group and control group, with both groups achieving similarly high rates (> 90%) of ERAS success. There were also no differences in 30-day postoperative complications and 6-month postoperative clinical outcomes. CONCLUSION: Patients with severe preoperative varus deformity undergoing ERAS TKA achieved high ERAS success rates (> 90%). Genu varum is not a contraindication for ERAS TKA.

The patient acceptable symptom state for the knee society score, oxford knee score and short form-36 following unicompartmental knee arthroplasty.

PURPOSE: The patient acceptable symptom state (PASS) is a target value on a patient-reported outcome measures (PROM) scale beyond which patients deem themselves to have attained an acceptable outcome. This study aimed to define the PASS thresholds for generic and knee-specific PROMs at 2 years after unicompartmental knee arthroplasty (UKA). METHODS: Prospectively collected data of 955 patients who underwent UKA for medial osteoarthritis at a single institution was reviewed. Patients were assessed preoperatively and 2 years postoperatively using the Knee Society Knee Score (KSKS), Function Score (KSFS), Oxford Knee Score (OKS), SF-36 Physical Component Score (PCS) and Mental Component Score (MCS). Responses to an anchor question assessing patients' overall rating of treatment results were dichotomized and used to determine if PASS was achieved. PASS thresholds for each PROM were selected based on the Youden index on a receiver operating characteristics (ROC) curve. Sensitivity analyses were performed for different subgroups (by age, gender, BMI), baseline score tertiles and an alternate definition of PASS. RESULTS: In total, 92.7% reported their current state as acceptable. The areas under the curve (AUC) for ROCs were 0.72-0.83, except for the SF-36 PCS (AUC 0.64), indicating good discriminative accuracy of the other PROMs. PASS thresholds were 85.5 for KSKS, 77.5 for KSFS, 41.5 for OKS, 49.9 for SF-36 PCS and 54.6 for SF-36 MCS. Sensitivity analyses revealed that the thresholds were robust. Patients who attained a PASS were at least 4-5 times more likely to be satisfied and have expectations fulfilled. CONCLUSION: PASS thresholds can be used to define treatment success in future outcome studies. At the individual level, they provide clinically relevant benchmarks for surgeons when assessing postoperative recovery. LEVEL OF EVIDENCE: III.

Clinical Frailty Scale is a better predictor for adverse post-operative complications and functional outcomes than Modified Frailty Index and Charlson Comorbidity Index after total knee arthroplasty.

PURPOSE: Studies have demonstrated correlations between frailty and comorbidity scores with adverse outcomes in total knee replacement (TKR). However, there is a lack of consensus on the most suitable pre-operative assessment tool. This study aims to compare Clinical Frailty Scale (CFS), Modified Frailty Index (MFI), and Charlson Comorbidity Index (CCI) in predicting adverse post-operative complications and functional outcomes following a unilateral TKR. METHODS: In total, 811 unilateral TKR patients from a tertiary hospital were identified. Pre-operative variables were age, gender, body mass index (BMI), American Society of Anesthesiologists (ASA) class, CFS, MFI, and CCI. Binary logistic regression analysis was performed to ascertain odd ratios of pre-operative variables on adverse post-operative complications (length of stay < LOS >, complications, ICU/HD admission, discharge location, 30-day readmission, 2-year reoperation). Multiple linear regression analyses were used to estimate the standardized effects of pre-operative variables on the Knee Society Functional Score (KSFS), Knee Society Knee Score (KSKS), Oxford Knee Score (OKS), and 36-Item Short Form Survey (SF-36). RESULTS: CFS is a strong predictor for LOS (OR 1.876, p < 0.001), complications (OR 1.83-4.97, p < 0.05), discharge location (OR 1.84, p < 0.001), and 2-year reoperation rate (OR 1.98, p < .001). ASA and MFI were predictors for ICU/HD admission (OR:4.04, p = 0.002; OR 1.58, p = 0.022, respectively). None of the scores was predictive for 30-day readmission. A higher CFS was associated with a worse outcome for 6-month KSS, 2-year KSS, 6-month OKS, 2-year OKS, and 6-month SF-36. CONCLUSION: CFS is a superior predictor for post-operative complications and functional outcomes than MFI and CCI in unilateral TKR patients. This suggests the importance of assessing pre-operative functional status when planning for TKR. LEVEL OF EVIDENCE: Diagnostic, II.

Cost-Effectiveness of Robot-Assisted Total Knee Arthroplasty: A Markov Decision Analysis.

BACKGROUND: Robot-assisted total knee arthroplasty (rTKA) may improve clinical outcomes for patients who have end-stage osteoarthritis of the knee. However, the costs of rTKA are high, and there is a paucity of data evaluating the cost-effectiveness of rTKA. We aimed to analyze the cost per quality-adjusted life-year (QALY) of rTKA relative to manual TKA. METHODS: A Markov decision analysis was performed using known parameters for costs, outcomes, implant survivorships, and mortalities. The cost-effectiveness of rTKA relative to manual TKA was assessed for end-stage knee osteoarthritis patients who had a mean age of 65 years (range, 27 to 94 years). The rTKA costs were calculated for a pay-per-use contract robot. RESULTS: Using the Markov Model with an annual case volume of 500 patients and a mean age of 65 years, the overall health gain per patient was 13.34 QALYs after rTKA and 13.31 QALYs after manual TKA. This resulted in an overall gain in QALYs of 0.03 for each patient undergoing an rTKA compared with manual TKA and an incremental cost of $128,526 Singapore Dollars per QALY. CONCLUSION: Robotic TKA is not a cost-effective alternative to conventional TKA using a pay-per-use contract robot.

The effect of topical tranexamic acid on functional outcomes and quality of life in patients undergoing unicompartmental knee arthroplasty.

INTRODUCTION: Tranexamic acid (TXA) is being increasingly utilized to reduce blood loss after knee joint arthroplasty. However, there is a lack of studies on the effect of topical TXA on the functional outcomes and quality of life after Unicompartmental Knee Arthroplasty (UKA). The aim of this study was to determine the effect of topical TXA on functional outcomes and quality of life scores in patients undergoing UKA. MATERIALS AND METHODS: We retrospectively analysed patients undergoing unilateral UKA at a single tertiary hospital from 2005 to 2017. Patients were divided into 2 groups: (1) The control group which did not receive TXA (n = 742); (2) The TXA group which received topical TXA (n = 331). Functional outcomes were assessed using the Knee Society Function Score (KSFS), Knee Society Knee Score (KSKS) and Oxford Knee Score (OKS), while quality of life was evaluated with the Physical Component Score (PCS) and Mental Component Score (MCS) of Short-Form 36 (SF-36) preoperatively and at 6 months and 2 years follow-up. RESULTS: At 6 months and 2 years post-surgery, there were no significant differences in the functional scores between the groups. The number of patients who attained minimum clinically important difference (MCID) for each of the functional scores was also comparable between the groups. CONCLUSIONS: In patients undergoing UKA, functional outcomes and quality of life scores were comparable between those who received topical TXA and those who did not. There was no significant improvement or impairment in knee function associated with topical TXA administration in UKA up to 2 years follow-up.

All-polyethylene unicompartmental knee arthroplasty is associated with increased risks of poorer knee society knee score and lower satisfaction in obese patients.

BACKGROUND: Although metal-backed tibial component (MB) is biomechanically superior to all-polyethylene (AP) implants in fixed-bearing unicompartmental knee arthroplasty (UKA), recent studies have shown comparable functional outcomes between the two. However, no study has examined this comparison in obese patients (BMI ≥ 30 kg/m2). We investigated whether functional outcomes between the two implants differ among obese patients, and whether the extent of obesity influences these outcomes. PATIENTS AND METHODS: Four hundred twenty-two UKA implants from 347 obese patients were reviewed retrospectively. Patients were assessed using the Knee Society Knee Score (KSKS) and Function Score (KSFS), the original Oxford Knee Score (OKS), and SF-36 Physical Component Summary (PCS) and Mental Component Summary (MCS). Minimal clinically important difference (MCID) attainment was recorded. Patients' fulfillment of expectations and satisfaction with the surgery outcome was also graded. Patients were further divided into lower obesity (BMI 30-34.9 kg/m2) and higher obesity (BMI ≥ 35 kg/m2) to examine effect modification. RESULTS: There were no differences in functional outcomes and quality-of-life scores, MCID attainment of functional scores, as well as satisfaction and expectation fulfillment between AP and MB. Among higher obesity patients, AP was associated with a poorer KSKS (p = 0.031) and lower proportion of satisfaction fulfillment (p = 0.041) 2 years postoperatively compared to MB. CONCLUSION: We found no differences in functional and quality-of-life outcomes between fixed-bearing AP and MB tibial components among obese patients who underwent UKA. However, among higher obesity patients (BMI ≥ 35 kg/m2), patients with AP tibial component were associated with lower KSKS score and a lower proportion of attaining satisfaction fulfillment 2 years postoperatively.

Early post-operative oxford knee score and knee society score predict patient satisfaction 2 years after total knee arthroplasty.

BACKGROUND: There is poor correlation between functional outcomes and patient satisfaction following total knee arthroplasty (TKA). We asked if early post-operative scores at 6 months or the pre- to post-operative change in scores are predictive of patient satisfaction 2 years after TKA. METHODS: We conducted a retrospective review of prospectively collected registry data of 4359 TKAs performed at a single institution. At 6 months and 2 years, the Knee Society Score (KSS), Oxford Knee Score (OKS), and Short-Form 36 scores were assessed. A satisfaction questionnaire was also completed. Logistic regression was used to generate receiver-operating characteristic (ROC) curves to assess the ability of each scoring system in predicting satisfaction at 2 years. RESULTS: At 2 years, 91.1% of patients were satisfied. For the absolute post-operative OKS at 6 months, an AUC of 0.762 (95% CI 0.736-0.788) and a threshold of ≤ 21.5 points (or ≥ 38.5 points on the new scale) were obtained. For the KSS knee score, an AUC of 0.704 (95% CI 0.674-0.734) and a threshold of ≥ 80.5 points were identified. The OKS performed significantly better than the KSS knee score (p = 0.03) and the other post-operative scores (p < 0.001). When analysing the change in scores pre-operatively to 6 months, the AUC was < 0.7 for all scales. CONCLUSIONS: Early post-operative scores, specifically the OKS and KSS knee score, can predict patient satisfaction at 2 years after TKA with good accuracy. The threshold values offer surgeons an additional tool to identify patients at risk of dissatisfaction at 2 years, enabling them to intervene earlier to ensure good patient satisfaction. LEVEL OF EVIDENCE: III, retrospective cohort study.

Can Octogenarians Undergoing Total Knee Arthroplasty Experience Similar Functional Outcomes, Quality of Life, and Satisfaction Rates as Their Younger Counterparts? A Propensity Score Matched Analysis of 1188 Patients.

BACKGROUND: Current literature lacks consensus regarding the impact of advanced age on the clinical outcomes of total knee arthroplasty (TKA). Moreover, there is paucity of literature on the subjective benefit reported by elderly patients. We compared the functional outcomes, quality of life, and satisfaction rates between octogenarians and age-appropriate controls undergoing primary TKA with a minimum follow-up of 2 years. METHODS: Prospectively collected registry data of 594 patients aged ≥80 years (n = 594) and a propensity score matched cohort of 594 patients aged 65-74 years who underwent primary TKA at a single institution were reviewed. The range of motion, clinical outcome scores, and satisfaction rates were assessed at 6 months and 2 years. Revision rates were also recorded. RESULTS: Octogenarians had a significantly lower Knee Society Function Score, Oxford Knee Score, and SF-36 Physical Component Summary at 6 months and 2 years (P < .05 for each). Furthermore, a lower proportion of octogenarians achieved the minimal clinically important difference for each score (P < .05 for each). Although the rates were similar at 6 months (P = .853), octogenarians were less satisfied at 2 years compared to age-appropriate controls (89.3% vs 93.3%, P = .042), and there was a trend toward poorer expectation fulfillment (88.4% vs 92.1%, P = .062). CONCLUSION: Octogenarians undergoing TKA had a relatively lower rate of satisfaction and clinically meaningful improvement compared to younger controls. Nevertheless, elderly patients still experienced a successful outcome after surgery. The clinical trajectory outlined may help clinicians provide valuable prognostic information to elderly patients and guide preoperative counseling.

Do Patients With Psychological Distress Have Poorer Patient-Reported Outcomes After Total Hip Arthroplasty?

BACKGROUND: Patients with psychological distress are likely to have poorer short-term functional outcomes after total knee arthroplasty. However, the influence of psychological distress on the outcomes of total hip arthroplasty (THA) is relatively understudied. Previous studies also had short follow-ups of 1 year or less. We examined the influence of psychological distress on patient-reported outcomes and satisfaction, and analyzed the change in mental health after THA at a minimum of 2 years. METHODS: Prospectively collected data of 1384 patients undergoing primary THA in 2001-2015 were reviewed. Patients were assessed using the Oxford Hip Score, Western Ontario and McMaster Universities Osteoarthritis Index, and 36-item Short-Form health survey Physical Component Summary and Mental Component Score (MCS). Patients were stratified into those with psychological distress (MCS < 50, n = 720) and those without (MCS ≥ 50, n = 664). Multiple regression analysis was used to control for age, gender, body mass index, and baseline scores. The rate of satisfaction and expectation fulfillment was also analyzed. RESULTS: Distressed patients had a poorer Physical Component Summary at 6 months. However, there was no difference in patient-reported outcomes at 2 years. A higher proportion of distressed patients attained the minimal clinically important difference for Oxford Hip Score and Western Ontario and McMaster Universities Osteoarthritis Index, while 92.2% of distressed patients and 92.9% of nondistressed patients were satisfied at 2 years (P = .724). There was no difference in MCS after 6 months. The percentage of distressed patients also declined from 41.8% to 27.3%. CONCLUSION: Patients with psychological distress achieved a comparable level of function, quality of life, and satisfaction 2 years after THA. Undergoing THA may also lead to mental health improvement in a subgroup of distressed patients.

Should patients aged 75 years or older undergo medial unicompartmental knee arthroplasty? A propensity score-matched study.

INTRODUCTION: With increasing life expectancies worldwide, more elderly patients with isolated medial compartment osteoarthritis may become suitable UKA candidates. However, there is a paucity of literature comparing outcomes between older patients (≥ 75 years) and younger patients undergoing UKA. The aim of this study was to determine if there were differences in functional and HRQoL measures between older patients (≥ 75 years) and younger controls (< 75 years) undergoing primary UKA. MATERIALS AND METHODS: Prospectively collected registry data of 1041 patients who underwent primary, cemented, fixed-bearing medial UKA at a single institution from 2002-2013 were reviewed. Propensity scores generated using logistic regression was used to match older patients (≥ 75 years, n = 94) to controls (< 75 years, n = 188) in a 1:2 ratio. Knee Society Scores, Oxford Knee Score, Short Form-36, satisfaction/expectation scores, proportion of patients attaining OKS/SF-36 PCS MCID and survivorship were analysed. RESULTS: Patients ≥ 75 years had significantly lower KSFS (67.1 ± 17.9 vs 79.4 ± 18.2, p < 0.001) and SF-36 PCS (47.3 ± 10.1 vs 50.4 ± 9.1, p = 0.01) as compared to the control group. In addition, a significantly lower proportion of patients ≥ 75 years attained MCID for SF-36 PCS when compared to the controls (50.0% vs 63.8%, p = 0.04). Survival rates at mean 8.3 ± 3.0 years were 98.9% (95% CI, 96.7-100) in the older group versus 92.8% (95% CI, 86.8-98.8) in the younger group (p = 0.31). CONCLUSIONS: Our findings highlight the need to counsel older patients regarding potentially reduced improvements in functional outcomes, despite advantages of lower revision. However, UKA in older patients continues to be a viable option for isolated medial compartment osteoarthritis LEVEL OF EVIDENCE: Level III Propensity score matched study.

Predicting Mobility Limitations in Patients With Total Knee Arthroplasty in the Inpatient Setting.

OBJECTIVE: To develop a prediction model for postoperative day 3 mobility limitations in patients undergoing total knee arthroplasty (TKA). DESIGN: Prospective cohort study. SETTING: Inpatients in a tertiary care hospital. PARTICIPANTS: A sample of patients (N=2300) who underwent primary TKA in 2016-2017. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Candidate predictors included demographic variables and preoperative clinical and psychosocial measures. The outcome of interest was mobility limitations on post-TKA day 3, and this was determined a priori by an ordinal mobility outcome hierarchy based on the type of the gait aids prescribed and the level of physiotherapist assistance provided. To develop the model, we fitted a multivariable proportional odds regression model with bootstrap internal validation. We used a model approximation approach to create a simplified model that approximated predictions from the full model with 95% accuracy. RESULTS: On post-TKA day 3, 11% of patients required both walkers and therapist assistance to ambulate safely. Our prediction model had a concordance index of 0.72 (95% confidence interval, 0.68-0.75) when evaluating these patients. In the simplified model, predictors of greater mobility limitations included older age, greater walking aid support required preoperatively, less preoperative knee flexion range of movement, low-volume surgeon, contralateral knee pain, higher body mass index, non-Chinese race, and greater self-reported walking limitations preoperatively. CONCLUSION: We have developed a prediction model to identify patients who are at risk for mobility limitations in the inpatient setting. When used preoperatively as part of a shared-decision making process, it can potentially influence rehabilitation strategies and facilitate discharge planning.

Modern TKA implants are equivalent to traditional TKA implants in functional and patellofemoral joint-related outcomes.

PURPOSE: To compare patient-reported outcomes measures, health-related quality of life and satisfaction rates between a new Modern TKA system (M-TKA) and an existing Traditional TKA system (T-TKA). METHODS: Prospectively collected registry data of 65 patients who underwent T-TKA and 65 patients who underwent M-TKA at a single institution from 2014 to 2015 was reviewed. The range of motion, Knee Society Knee Score (KSKS), Function Score (KSFS), Oxford Knee Score (OKS), SF-36, satisfaction and expectation fulfilment were compared at Pre-op, 6 months and 2 years. Patellofemoral joint-related OKS subscores (3, 5, 7, 12) were also compared between the groups. Minimal clinically important difference (MCID) in OKS/SF-36 were analysed for both groups. Propensity scores generated using logistic regression were used to adjust for confounding variables, thus allowing matching of T-TKA to M-TKA in a 1:1 ratio. RESULTS: Both groups showed a significant improvement in all measured variables at 6 month and 2 years (p < 0.001) when compared to baseline. There was no significant difference in KSKS, KSFS, OKS, SF-36 and Patellofemoral joint-related OKS subscores (3, 5, 7, 12) between the two groups (n.s.). At 2 years, there were high satisfaction rates of 89.2% and 92.2% in the T-TKA and M-TKA groups, respectively (n.s.). Similarly, both groups demonstrated high expectation fulfilment rates of 84.6% and 90.6% for the T-TKA and M-TKA groups, respectively (n.s.). CONCLUSION: Using an extensive battery of standardized patient-reported, health-related quality of life and MCID assessments, our study demonstrated no difference in clinical outcomes between M-TKA and T-TKA that would justify the use of the newer and costlier M-TKA. Longer follow-up is necessary to evaluate the possible advantages of this new implant design. LEVEL OF EVIDENCE: Level III, Retrospective Study.

Pre-existing patellofemoral disease does not affect 10-year survivorship in fixed bearing unicompartmental knee arthroplasty.

PURPOSE: The purpose of this study was to assess 10-year functional outcome and survivorship analysis of patients with significant radiographic evidence of patellofemoral joint arthritis treated with fixed bearing unicompartmental knee arthroplasty. METHODS: Two hundred and sixteen patients (263 knees) that underwent UKA from 2003 to 2005 for a mean of 10.5 ± 2.1 years were prospectively followed up. Preoperative radiological assessment of the patellofemoral joint state was assessed according to the Ahlback classification by an independent assessor and radiographically significant patellofemoral disease was defined as grade 2 or more. Patients with significant bone-on-bone contact in the patellofemoral joint were excluded. RESULTS: Of the 263 knees, 222 (84.4%) had normal patellofemoral joint state and 41 (15.6%) radiologically significant patellofemoral disease. At 10 years' follow-up, the normal and patellofemoral groups had similar OKS (20 ± 7 vs 20 ± 8, n.s.) and KSS scores (79 ± 20 vs 81 ± 20, n.s.), respectively. There were 12 revision surgeries in the normal group and the most common indication for revision was progression of contralateral compartment osteoarthritis (6 of 12 cases). There was only one revision in the patellofemoral group and it was due to progression of contralateral compartment osteoarthritis (n.s.). When all secondary surgeries to the operated knee were considered as failures, the 10-year survival rate was 95.1% (CI 95%: 92.2-97.7%). CONCLUSION: The presence of significant preoperative radiological patellofemoral disease does not affect long-term implant survival and patients have excellent functional outcomes 10 years postoperatively. These patients should not be contraindicated from undergoing unicompartmental knee arthroplasty. LEVEL OF EVIDENCE: III.

Postoperative fixed flexion deformity greater than 10° lead to poorer functional outcome 10 years after unicompartmental knee arthroplasty.

PURPOSE: The primary aim of this study was to evaluate the influence of postoperative fixed flexion deformity (FFD) on the clinical outcomes 10 years after unicompartmental knee arthroplasty (UKA). The secondary aim was to identify predictors for the occurrence of postoperative FFD. METHODS: Patients who underwent UKA between 2003 and 2007 were prospectively followed up for 10 years. A total of 172 patients were categorized into 3 groups based on the amount of postoperative FFD: (1) 0° or less (Min-FFD), (2) 1°-9° (Mid-FFD), and (3) 10° or more (Max-FFD). Functional outcome was quantified using Knee Society Function Score (KSFS), Knee Society Knee Score (KSKS) and Oxford Knee Score (OKS). RESULTS: At 10 years after UKA, the mean KSKS and OKS were 6 ± 5 (95% CI 6-18, p = 0.050) and 5 ± 2 (95% CI 0-9, p = 0.041) points lower in patients with Max-FFD than those with Min-FFD. Other clinical outcomes were not different between groups. Patients with a higher preoperative body mass index (OR 1.122 per unit increase, 95% CI 1.006-1.253, p = 0.040) or worse preoperative FFD (OR 1.108 per unit increase, 95% CI 1.022-1.201, p = 0.013) were at increased risk of having postoperative FFD of 10° or more at 10 years after UKA. CONCLUSIONS: The clinical relevance of this study was to demonstrate the long-term negative correlation between severe postoperative FFD and functional outcome and, therefore, the importance of achieving good knee alignment after UKA. The authors recommend that FFD should be fully corrected intra-operatively if possible while preserving knee balance and stable dynamic function through full range of motion. LEVEL OF EVIDENCE: Prognostic level II.

Patients With Poor Baseline Mental Health Undergoing Unicompartmental Knee Arthroplasty Have Poorer Outcomes.

BACKGROUND: The relationship between mental health and outcomes of unicompartmental knee arthroplasty (UKA) remains unclear. Poor preoperative mental health may be caused by pain and functional limitations associated with knee arthritis. We aimed at (1) investigating the effect of preoperative mental health on early outcomes and (2) assessing whether mental health improves after UKA. METHODS: Prospectively collected registry data of 1473 medial UKAs performed at a single institution in 2007-2014 were reviewed. Linear regression was used to determine improvement in mental health up to 2 years according to preoperative Short-Form 36 Mental Component Summary (MCS). Patients were stratified into low MCS (<50, n = 579) and high MCS (≥50, n = 894). The Knee Society Knee Score (KSKS), Function Score (KSFS), Oxford Knee Score (OKS), Short-Form 36, satisfaction, and expectation fulfilment were compared at 6 months and 2 years. RESULTS: The mean preoperative MCS was 41.2 in low MCS group and 58.6 in high MCS group (P < .001). The high MCS group had higher KSKS, KSFS, OKS, and Physical Component Summary, and a greater proportion of patients were satisfied and had expectations fulfilled at 6 months and 2 years (P < .05). However, the low MCS group demonstrated greater improvement in KSKS, KSFS, and OKS (P < .05). Lower preoperative MCS score was predictive of greater improvement in MCS (coefficient = -0.662, R = -0.602, P < .001). CONCLUSION: Patients with poor mental health benefit from greater improvements in their mental health and knee function after UKA, but also have a greater dissatisfaction.

Change in Body Mass Index After Total Knee Arthroplasty and Its Influence on Functional Outcome.

BACKGROUND: There is often an assumption by patients that weight loss will occur once their knee pain is relieved by total knee arthroplasty (TKA). This study aims to evaluate (1) the change in patients' body mass index (BMI) after TKA; (2) if postoperative change in BMI influences functional outcome and survival rate of TKA; and (3) the predictive factors associated with change in BMI. METHODS: Seven thousand seven hundred thirty-three patients who underwent a primary TKA between 2001 and 2010 were included in this study. Functional outcome scores collected at 2 years after surgery include the Oxford Knee Score, Knee Society Function Score, Knee Society Knee Score, Physical Component Score, and Mental Component Score of short form 36. RESULTS: Among these patients, 1067 (14%) had reduction in BMI, 5045 (65%) maintained their BMI, and 1621 (21%) had gain in BMI. The differences in improvement in Oxford Knee Score, Knee Society Function Score, Knee Society Knee Score, and Physical Component Score among the 3 groups of patients were less than the known minimal clinically important difference of these scores. The 10-year survival rate of TKA was not influenced by patients' change in BMI after surgery (P = .435). Obese class I, II, and III patients were more likely to reduce their BMI after TKA than those with normal preoperative BMI (P = .002, P = .012, and P = .004, respectively), while older patients were less likely to have gain in BMI after surgery (P = .001). CONCLUSION: A change in BMI after TKA did not influence the functional outcome clinically or the survival rate of the TKA implant.

Accelerometer-Based and Computer-Assisted Navigation in Total Knee Arthroplasty: A Reduction in Mechanical Axis Outliers Does Not Lead to Improvement in Functional Outcomes or Quality of Life When Compared to Conventional Total Knee Arthroplasty.

BACKGROUND: Accelerometer-based navigation (ABN) is a novel navigation system that attempts to combine the accuracy of computer-assisted surgery (CAS) with the familiarity of conventional instrumentation (CON). No studies have compared the clinical outcomes of this new technology with existing techniques to date. METHODS: From July 2013 to April 2014, 152 consecutive patients (152 knees) underwent total knee arthroplasty using ABN (n = 38), CAS (n = 38), or CON (n = 76). We prospectively matched the groups in a 1:1:2 ratio for age, gender, body mass index, preoperative range of motion, Knee Society Score, Oxford Knee Score, Short-Form 36 Physical and Mental Component Scores, and preoperative deformity using preoperative data in isolation, thus controlling for potential confounding factors. All patients were prospectively followed for 2 years. RESULTS: The ABN and CAS groups had a significantly improved mean mechanical axis (P = .018), femoral (P = .050) and tibial component alignment (P = .008) compared to the CON group. There were significantly less mechanical axis outliers in the ABN and CAS groups (P = .034). The duration of surgery for the ABN group (83.9 ± 21 min) was significantly shorter than the CAS group (101 ± 11 min; P < .001) but similar to the CON group (76.6 ± 17 min; P = .131). There was no significant difference in functional outcomes, quality of life measures or satisfaction rates between the 3 groups at 2 years (P > .05). CONCLUSION: Although bone cuts were as accurate as CAS and operation time was similar to CON, the use of ABN failed to demonstrate any advantages in clinical outcomes following total knee arthroplasty at 2 years follow-up.

Unicompartmental Knee Arthroplasty Achieves Greater Flexion With No Difference in Functional Outcome, Quality of Life, and Satisfaction vs Total Knee Arthroplasty in Patients Younger Than 55 Years. A Propensity Score-Matched Cohort Analysis.

BACKGROUND: Improvements in surgical techniques, implant design, and adherence to indications have resulted in favorable outcomes after unicompartmental knee arthroplasty (UKA), particularly in an older population. However, no studies have compared the performance of contemporary UKA and total knee arthroplasty (TKA) in a young population. METHODS: Prospectively collected registry data of 160 UKAs performed in 160 patients younger than 55 years were reviewed. Propensity scores generated using logistic regression were used to adjust for confounding variables of age, gender, body mass index, preoperative range of motion, Knee Society Score, Oxford Knee Score, and Short-Form 36, allowing matching of the TKA cohort to the UKA cohort in a 1:1 ratio using the nearest-neighbor method. RESULTS: The UKA group had significantly greater flexion at 6 months and 2 years (P < .001). There was no significant difference in Knee Society Score, Oxford Knee Score, and Short-Form 36. At 2 years, 89.4% and 88.8% of the TKA and UKA groups were satisfied (P = 1.00) while 86.9% and 86.3% had their expectations fulfilled (P = 1.00). At a mean follow-up of 7 years, there were 2 revisions in each group (2.2%). CONCLUSION: Although native knee biomechanics are preserved, younger patients do not seem to perceive this oft-cited benefit of UKA, as this did not translate into greater health-related quality of life or patient satisfaction compared to TKA. The theoretical advantages of UKA were not borne out by our findings, other than greater flexion up to 2 years postoperatively.

Robotic-assisted total knee arthroplasty may lead to improvement in quality-of-life measures: a 2-year follow-up of a prospective randomized trial.

PURPOSE: Despite reduction in radiological outliers in previous randomized trials comparing robotic-assisted versus conventional total knee arthroplasty (TKA), no differences in short-term functional outcomes were observed. The aim of this study was to determine whether there was improvement in functional outcomes and quality-of-life (QoL) measures between robotic-assisted and conventional TKA. METHODS: All 60 knees (31 robotic-assisted; 29 conventional) from a previous randomized trial were available for analysis. Differences in range of motion, Knee Society (KSS) knee and function scores, Oxford Knee scores (OKS), SF-36 subscale and summative (physical PCS/mental component scores MCS) were analysed. In addition, patient satisfaction, fulfilment of expectations and the proportion attaining a minimum clinically important difference (MCID) in KSS, OKS and SF-36 were studied. RESULTS: Both robotic-assisted and conventional TKA displayed significant improvements in majority of the functional outcome scores at 2 years. Despite having a higher rate of complications, the robotic-assisted group displayed a trend towards higher scores in SF-36 QoL measures, with significant differences in SF-36 vitality (p = 0.03), role emotional (p = 0.02) and a larger proportion of patients achieving SF-36 vitality MCID (48.4 vs 13.8 %, p = 0.009). No significant differences in KSS, OKS or satisfaction/expectation rates were noted. CONCLUSION: Subtle improvements in patient QoL measures were observed in robotic-assisted TKA when compared to conventional TKA. This finding suggests that QoL measures may be more sensitive and clinically important than surgeon-driven objective scores in detecting subtle functional improvements in robotic-assisted TKA patients. LEVEL OF EVIDENCE: II.

Patient-Reported Outcomes, Quality of Life, and Satisfaction Rates in Young Patients Aged 50 Years or Younger After Total Knee Arthroplasty.

BACKGROUND: Recent studies have shown a discrepancy between traditional functional outcomes and patient satisfaction, with some reporting less than 85% satisfaction in older patients undergoing total knee arthroplasty (TKA). As native knee biomechanics are not completely replicated, the resulting functional limitations may cause dissatisfaction in higher-demand individuals. Few studies have recorded patient-reported outcomes, health-related quality of life scores, and patient satisfaction in a young population undergoing TKA. METHODS: One hundred thirty-six primary TKAs were performed in 114 patients aged 50 years or younger (mean age, 47.0 years; range, 30-50 years) at a single institution. The main diagnoses were osteoarthritis (85%) and rheumatoid arthritis (10%). RESULTS: The range of motion, Knee Society Score, Oxford Knee Score, and Physical and Mental Component Scores of Short Form-36 increased significantly (P < .001). At 2 years, 85.3% of patients had good/excellent knee scores, 71.3% had good/excellent function scores, 94.9% met the minimal clinically important difference for the Oxford Knee Score, and 84.6% met the minimal clinically important difference for the Physical Component Score. We found that 88.8% of patients were satisfied with their surgeries, whereas 86.8% had their expectations fulfilled. Survivorship using revision as an end point was 97.8% at a mean of 7 years (range, 3-16 years). CONCLUSION: Patients aged 50 years or younger undergoing TKA can experience significant improvements in their quality of life, have their expectations met, and be satisfied with their surgeries, at rates similar to those of non-age-restricted populations. Surgeons should inform them of these benefits and the potential risk of revision surgery in the future, albeit increasingly shown to be low.