Not all questions are created equal: the weight of the Oxford Knee Scores questions in a multicentric validation study.

BACKGROUND: The Oxford Knee Score (OKS) has been designed for patients with knee osteoarthritis and has a widespread use. It has 12 questions, with each question having the same weight for the overall score. Some authors have observed a significant ceiling effect, especially when distinguishing slight postoperative differences. We hypothesized that each questions' weight will depend significantly on the patient's sociodemographic data and lifestyle. METHODS: In this international multicentric prospective study, we included patients attending a specialist outpatient knee clinic. Each patient filled out 3 questionnaires: (a) demographic data and data pertaining to the OKS, (b) the standard OKS, and (c) the patient gave a mark on the weight of the importance of each question, using a 5-point Likert scale (G OKS). Linear regression models were used for the analysis. RESULTS: In total 203 patients (106 female and 97 male) with a mean age of 64.5 (±12.7) years and a mean body mass index (BMI) of 29.34 (±5.45) kg/m2 were included. The most important questions for the patients were the questions for pain, washing, night pain, stability, and walking stairs with a median of 5. In the regression models, age, gender, and driving ability were the most important factors for the weight of each of the question. CONCLUSION: The questions in the OKS differ significantly in weight for each patient, based on sociodemographic data, such as age, self-use of a car, and employment. With these differences, the Oxford Knee Score might be limited as an outcome measure. Adjustment of the OKS that incorporates the demographic differences into the final score might be useful if the ceiling effect is to be mitigated. LEVEL OF EVIDENCE: Level II prospective prognostic study.

No effect of tourniquet in primary total knee arthroplasty on muscle strength, functional outcome, patient satisfaction and health status: a randomized clinical trial.

PURPOSE: Tourniquet use during primary total knee arthroplasty (TKA) may negatively impact the early postoperative functional recovery due to molecular effects of ischaemia. The hypothesis of the present study was that primary TKA without a tourniquet positively influences the postoperative muscle strength, functional outcome, patient satisfaction and health status. METHODS: The monocentric, randomized, controlled trial included a total of 99 patients scheduled to undergo primary TKA (ClinicalTrials.gov NCT02475603). The patients were randomly assigned to the tourniquet (n = 50) or non-tourniquet (n = 49) group after receiving a written informed consent. As primary outcome parameter, the functional outcome, patient expectation/satisfaction and the health status were assessed preoperatively, 6 weeks, 6 months postoperatively using Oxford knee score, WOMAC score, Mancuso score, EQ-5D index, EQ-VAS, anxiety score, depression score, hospital anxiety and depression scale, respectively. Additionally, a rope pulley isokinetic system (Moflex, Recotec/Bernina, Switzerland) was applied to quantify the muscle strength preoperatively, 1 week, 6 weeks and 6 months postoperatively. RESULTS: No difference in any of the outcome parameters could be observed between the groups at all time points after TKA (n.s.). Also the isokinetic muscle strength of the knee joint as quantified by concentric/eccentric peak force (N), workload (J), total workload (J) and power (W) did not reveal statistically significant differences between the groups and time points. However, in both groups improved results were found with respect to the functional outcome, patient satisfaction, health status and isokinetic muscle strength up to 6 months postoperatively. CONCLUSIONS: The application of the tourniquet did not affect the isokinetic muscle strength, the functional outcome, the patient satisfaction and the health status following primary TKA. However, with and without tourniquet use, the level of the knee functionality, the patient satisfaction as well as the health status improved significantly. LEVEL OF EVIDENCE: I.

Patients with anteromedial osteoarthritis achieve the greatest improvement in patient reported outcome after total knee arthroplasty.

The osteoarthritic (OA) disease pattern of the knee is one of the determinants for choice of arthroplasty concept when knee replacement is indicated, but whether the disease pattern has a direct effect on postoperative outcome has not previously been investigated. The aim was to investigate if different OA disease patterns have an effect on postoperative outcome after receiving total knee arthroplasty (TKA). MATERIALS AND METHODS: 472 patients with pre- and 1-year postoperative patient reported outcome measures (PROMs) undergoing TKA surgery were retrospectively identified and classification of the OA disease pattern was made on preoperative radiographs. Measured resection was the universal technical approach. RESULTS: The key findings showed greater improvement in mean PROMs for anteromedial OA (AMOA) compared with other OA disease patterns; 3.1 points (95% CI 1.4-4.7, p < 0.001) in Oxford Knee score, 11.7 points (95% CI 0.9-22.5, p = 0.034) in Forgotten Joint score and 0.08 points (95% CI 0.02-0.14, p = 0.007) in EQ 5D score. Similar results were observed when comparing AMOA with AMOA that had only partial thickness cartilage loss (AMOA-PTCL). CONCLUSIONS: Patients with AMOA achieve greater improvement in PROMs after TKA surgery when using measured resection compared with other OA disease patterns. This finding has important implications for reporting, risk stratification and interpretation in TKA outcome studies, including randomized trials, why further investigation of the topic is of highly relevance.

Randomized clinical trial of medial unicompartmentel versus total knee arthroplasty for anteromedial tibio-femoral osteoarthritis. The study-protocol.

BACKGROUND: In treatment of isolated medial unicondylar osteoarthritis of the knee, it is possible to choose between medial unicondylar knee arthroplasty (mUKA), or a total knee prosthesis (TKA). The demand for a blinded multicenter RCT with the comparison of mUKA and TKA has been increasing in recent years, to determine which prosthesis is better. Supporters of TKA suggest this treatment gives a more predictable and better result, whereas supporters of UKA suggest it is unnecessary to remove functional cartilage in other compartments. If the mUKA is worn or loosens, revision surgery will be relatively easy, whereas revision-surgery after a TKA can be more problematic. METHODS: A double-blinded multicenter Randomized Clinical Trial setup is the aim of the study. 6 hospitals throughout all 5 municipal regions of Denmark will be participating in the study. 350 patients will be included prospectively. Follow-up will be with PROM-questionnaires and clinical controls up to 20 years. DISCUSSION: Results will be assessed in terms of 1) PROM-questionnaires, 2) Clinical assessment of knee condition, 3) cost analysis. To avoid bias, all participants except the theatre-staff will be blinded. PROMS: OKS, KOOS, SF36, Forgotten Joint Score, EQ5D, UCLA activity scale, Copenhagen Knee ROM scale, and Anchor questions. Publications are planned at 2, 5 and 10 years after inclusion of the last patient. The development of variables over time will be analyzed by calculating the area under the curve (AUC) for the variable relative to the initial value, and comparisons of the between-group differences will be based on parametric statistics. In this study, we feel that we have designed a study that will address these concerns with a well-designed double-blinded multicentre RCT. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT03396640 . Initial Release: 09/19/2017. Date of enrolment of first participant: 10/11/17.

Similar postoperative patient-reported outcome in both second generation patellofemoral arthroplasty and total knee arthroplasty for treatment of isolated patellofemoral osteoarthritis: a systematic review.

INTRODUCTION: Due to inconsistent results and high failure rates, total knee arthroplasty (TKA) is more often used to treat isolated patellofemoral osteoarthritis (PFOA) despite the theoretical advantage of patellofemoral arthroplasty (PFA). It is perceived that second-generation PFA may have improved the outcomes of surgery. In this systematic review, the primary aim was to compare outcomes of second-generation PFA and TKA by assessment of patient-reported outcome measures (PROMs). METHODS: A systematic search was made in PubMed, Medline, Embase, Cinahl, Web of Science, Cochrane Library and MeSH to identify studies using second-generation PFA implants or TKA for treatment of PFOA. Only studies using The American Knee Society (AKSS), The Oxford Knee Score (OKS) or The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) to report on PROMs were included. RESULTS: The postoperative weighted mean AKSS knee scores were 88.6 in the second-generation PFA group and 91.8 in the TKA group. The postoperative weighted mean AKSS function score was 79.5 in the second-generation PFA group and 86.4 in the TKA group. There was no significant difference in the mean AKSS knee or function scores between the second-generation PFA group and the TKA group. The postoperative weighted mean OKS score was 36.7 and the postoperative weighted mean WOMAC score was 24.4. The revision rate was higher in the second-generation PFA group (113 revisions [8.4%]) than in the TKA group (3 revisions [1.3%]). Progression of OA was most commonly noted as the reason for revision of PFA, and it was noted in 60 cases [53.1%]; this was followed by pain in 33 cases [29.2%]. CONCLUSION: Excellent postoperative weighted mean AKSS knee scores were found in both the second-generation PFA group and in the TKA group, suggesting that both surgical options can result in a satisfying patient-reported outcome. Higher revision rates in the second-generation PFA studies may in part be due to challenges related to patient selection. Based on evaluation of PROMs, the use of second-generation PFA seems to be an equal option to TKA for treatment of isolated PFOA in appropriately selected patients. Hopefully, this can be considered by physicians in their daily clinical work. LEVEL OF EVIDENCE: IV.

The Oxford knee score and its subscales do not exhibit a ceiling or a floor effect in knee arthroplasty patients: an analysis of the National Health Service PROMs data set.

PURPOSE: In this study, we examined whether the OKS demonstrated a floor or a ceiling effect when used to measure the outcome of knee replacement surgery in a large national cohort. METHODS: NHS PROMs database, containing pre- to 6 month post-operative OKS on 72,154 patients, mean age 69 (SD 9.4), undergoing knee replacement surgery, was examined to establish the proportion of patients achieving top or bottom OKS values pre- and post-operatively. RESULTS: Pre-operatively, none of patients achieved the maximum/'best' (48) and minimum (0) scores. Post-operatively, no patients (0 %) achieved the minimum/'worst' score, but the percentage achieving the maximum score increased to 2.7 %. Subgroup analyses demonstrated that the highest post-operative overall ceiling percentage was 3 %, in a subgroup of patients between 60 and 79 years of age and 13.7 % in a group of patients who had a pre-operative OKS above 41. Furthermore, 10.8 % of patients achieved the top post-operative OKS-PCS and 4.7 % top post-operative OKS-FCS. CONCLUSION: Based on NHS PROMs data, the OKS does not exhibit a ceiling or floor effect overall, or for both its pain and function subscales, and remains a valid measure of outcomes for patients undergoing TKA. LEVEL OF EVIDENCE: Large-scale retrospective observations study, Level II.

Does knee awareness differ between different knee arthroplasty prostheses? A matched, case-control, cross-sectional study.

BACKGROUND: Low knee awareness after Total Knee Arthroplasty (TKA) has become the ultimate goal in trying to achieve a natural feeling knee that meet patient expectations. To accommodate this manufacturers of TKAs have developed new prosthetic designs that potentially could give patients a more natural feeling knee during activities. The purpose af this study was to compare the Forgotten Joint Score (FJS) and Oxford Knee Score (OKS) of patients treated with a previous generation standard Cruciate Retaining (CR) TKA to the scores obtained by patients treated with a newer generation CR TKA or a mobile bearing CR TKA. METHODS: We identified all patients receiving a new generation CR TKA or mobile bearing TKA at our institution between 2010 and 2012. These were matched to a population of patients receiving a standard CR TKA regarding age, gender, year of surgery, Kellgren-Lawrence (KL) grade and pre- and postoperative knee alignment. Patients were asked to complete the FJS and OKS questionnaires. Of the 316 patients completing the survey 64 standard CR TKAs to 35 new generation CR TKAs and 121 standard CR TKAs to 68 mobile bearing TKAs were matched. The FJS and OKS scores of the three TKA designs were compared. RESULTS: When comparing the new generation CR TKAs to the standard CR TKAs we found statistically significant higher OKS and FJS scores (6 (p = 0.04) and 16 (p = 0.03) points respectively) for the new generation CR TKAs. When comparing the mobile bearing TKAs to the standard CR TKAs we found a statistically significant higher OKS score (3 points, p = 0.04), and a higher but non-significant FJS score (4 points, p = 0.48) for the mobile bearing TKAs. CONCLUSIONS: Patients receiving the new generation CR TKA obtained higher FJS and OKS scores when compared to patients receiving a standard CR TKA, indicating that the use of this newer prosthetic design facilitate less knee awareness and better function after TKA.

Functional and Radiological Outcome of Simultaneous Bilateral Total Knee Replacement in a Tertiary Care Centre : A Quasi-prospective Study.

Introduction: Osteoarthritis (OA) is the most frequent joint disease with a prevalence of 5313 per 100,000 persons in India. OA of the knee is a major contributor to mobility impairment, particularly among women. In these patients, total knee replacement (TKR) is widely accepted as the gold standard treatment for pain relief and restoration of function. Now, patients have the option of undergoing either a simultaneous bilateral TKR or a staged TKR. The former has shown significant advantages such as shorter rehabilitation, cost efficacy and shorter hospital stay. This study aimed to assess the functional and radiological outcome of simultaneous bilateral TKR in a tertiary care centre. Materials and Methods: 30 adult patients above the age of 55 years with severe OA knee who underwent simultaneous bilateral TKR between 2022-2023 were included in this prospective study. Preoperatively, they were assessed with radiographs including full length scannograms. Mean Anatomical Axis, Mean Mechanical Axis and Mechanical Axis Deviation (Varus) were calculated based on the scannograms by a single observer. The same observer administered the oxford knee score (OKS) preoperatively to all patients. Regular clinical and radiological follow up was done. After 1 year follow up, the same observer administered the Oxford Knee Score (OKS) to the operated knee. Results: With a female preponderance among the study subjects (56.7%), the majority of the cases in our cohort were characterised as Grade IV Kellgren-Lawrence radiological grade of Osteoarthritis (76.66%) and were found to have tricompartmental involvement (70%). The mean anatomical axis for the right and left lower limb were 4.56±5.17 and 9.68±1.72 respectively. The mean mechanical axis deviation (Varus) for the right and left lower limb were 31.6±15.1 and 52.0±13.9 respectively. Preoperatively, mean mechanical axis for the right and left lower limb were 9.95±4.31 and 14.2 ±0.67 respectively. Postoperatively, mechanical axis was restored to near-normal values (3-5 degrees). Significant improvement in mean OKS from a preoperative value of 18.30 ± 3.46 to postoperative value of 33.50 ± 5.32 was noted at 1 year. Conclusion: Treatment of severe bilateral OA knee with simultaneous single staged bilateral TKR ensures good functional outcome , early mobility with minimal complications.

Item response theory validation of the Oxford knee score and Activity and Participation Questionnaire: a step toward a common metric.

OBJECTIVES: The Oxford knee score (OKS) and OKS Activity and Participation Questionnaire (OKS-APQ) are patient-reported outcome measures used to assess people undergoing knee replacement surgery. They have not explicitly been tested for unidimensionality (whether they measure one underlying trait such as 'knee health'). This study applied item response theory (IRT) to improve the validity of the instruments to optimize for ongoing use. STUDY DESIGN AND SETTING: Participants undergoing primary total knee replacement (TKR) provided preoperative and postoperative responses for OKS and OKS-APQ. Confirmatory factor analysis (CFA) were performed on the OKS and OKS-APQ separately and then on both when pooled into one. An IRT model was fitted to the data. RESULTS: 2972 individual response patterns were analyzed. CFA demonstrated that when combining OKS and OKS-APQ as one instrument, they measure one latent health trait. A user-friendly, free-to-use, web app has been developed to allow clinicians to upload raw data and instantly receive IRT scores. CONCLUSIONS: The OKS and OKS-APQ can be combined to use effectively as a single instrument (producing a single score). For the separate OKS and OKS-APQ the original items and response options can continue to be posed to patients, and this study has confirmed the suitability of IRT-weighted scoring. Applying IRT to existing responses converts traditional sum scores into continuous measurements with greater granularity, including individual measurement error.

Outcomes Following Staged Bilateral Total Knee Replacements: The Influence of First-Side Surgery on Results of the Second Side.

Background In the UK, the vast majority of bilateral total knee replacements (BTKRs) are performed as staged procedures. Historically, the second-operated knee, in patients undergoing staged BTKRs, has poorer outcomes compared with the first-operated knee. The aim was to review patient-reported outcome measures (PROMs) for staged BTKRs. To further assess if outcomes from the first side of surgery can predict results on the second side. Methods A retrospective analysis was conducted on a consecutive cohort of staged BTKRs using the same approach and technique from August 2009 to January 2020. PROMs were recorded by means of Oxford Knee Scores (OKS) preoperatively, at six weeks postoperatively, and at one year. The minimal important change (MIC) in PROMs was set at ≥5. Results A total of 186 consecutive staged BTKRs were carried out in 93 patients. The average interval between surgeries was 28 months, ranging from 3 to 100 months. The mean age was 65.3 years for the first side and 67.7 years for the second side, with 58.1% of the patients (54/93) being female. The mean body mass index (BMI) was 35.1 for the first side and increased to 35.8 for the second side (p=0.503). One-year follow-up PROMs were available for 97.8% of the first-side surgeries and 89.2% of the second-side surgeries. The average improvement in PROMs at one year was 18.3 for the first side and 15.8 for the second side (p=0.108). A total of 95.6% of patients achieved the MIC for the first side, while 87.9% achieved it for the second side (p=0.340). Fourteen TKRs performed in 13 patients did not achieve MIC at one year. Among these 13 patients, three (23.1%) did not reach MIC after the first-side surgery, compared to nine (61.5%) after the second-side surgery. One patient did not achieve MIC for either side. Of the 14 TKRs that failed to reach MIC in one year, 10 eventually met MIC in two years. The four TKRs that did not achieve MIC at two years were performed on females with high BMIs. Conclusion This study found no significant difference in PROMs improvements between the first and second sides of staged BTKRs at one-year follow-up. A failure to reach the MIC on one side does not affect the success of the other side. Most patients who do not achieve MIC in one year are likely to reach it in two years. Persistent poor scores were associated with high BMI and female sex.

Evaluating the Minimum Clinically Important Difference and Patient Acceptable Symptom State for the Womac Osteoarthritis Index after Unicompartmental Knee Arthroplasty.

Patient-Reported Outcome Measures (PROMs) are standardized questionnaires that gather information on health-related quality of life directly from patients. Since a significant statistical mean change may not correspond to a clinical improvement, there is a need to calculate a considerable change in scores. This is done by the Minimum Clinically Important Difference (MCID) and Patient Acceptable Symptom State (PASS). The objective of this article is to report the MCID and the PASS values of the WOMAC (Western Ontario and McMaster University) osteoarthritis index for patients undergoing Unicompartmental Knee Arthroplasty (UKA). A total of 37 patients (25 females and 12 males; mean age 68 ± 8.1 years and mean BMI 28.7 ± 4) who underwent UKA were enrolled. All patients were assessed using the WOMAC and the Oxford Knee Score (OKS) questionnaires before and six months following the procedure. To measure the cut-off values for MCID, distribution methods and anchor methods were applied, while the PASS was assessed only via anchor approaches. The MCID related to the WOMAC average global score was 90.7 ± 7.6, the average pain dimension score was 93.2 ± 6.6, the average stiffness dimension score was 92.6 ± 17, and the average physical function dimension score was 89.7 ± 7.6. In terms of PASS, the normalized WOMAC was 82.8, the pain dimension was 87.5, the stiffness dimension was 93.7, and the functional dimension was 83.1. A 34.5 amelioration in the WOMAC score, from initial evaluation to final follow-up, using change in OKS > 5 as anchor, indicates that the patients' health state improved to a clinically significant degree. A value at least of 82.8 in WOMAC score after treatment denotes that the symptom state is deemed acceptable by most of the patients.

Orthopaedic knee scooter-related injury: prevalence and patient safety perception in a prospective cohort with exploratory risk factor analysis.

BACKGROUND: There is a paucity of research investigating the harms associated with orthopaedic knee scooter (OKS) use and patient safety perceptions. This prospective study aimed to define the prevalence of OKS-related injuries, describe the patient perceptions of OKS safety, and identify potential risk factors. METHODS: This study was conducted at a single foot and ankle fellowship-trained surgeon's community-based clinic from 6/2020 to 4/2021 and enrolled 134 patients. Our primary outcome was an OKS-related event (injury or fall) and informed an a priori power analysis. Point estimate of association magnitude was calculated as an odds ratio (OR) for statistically and clinically significant associations. RESULTS: There were 118 (88%) patients eligible for analysis; fourteen enrolled patients did not use OKS, and two withdrew. The prevalence of patient falls was 37% (44/118), and the prevalence of patient injury was 15% (18/118). Four percent of patients would not recommend OKS and 8% would not use an OKS again. Sedentary lifestyle increased risk (OR = 4.67, 1.52-14.35 95 CI) for OKS-related injury. CONCLUSIONS: Despite a high prevalence of patient falls (37%), there is a low prevalence of injury (15%) and a favorable perception of OKS safety. Sedentary lifestyles may be a risk factor for OKS-related injury and should be considered in the development of a risk model.

Mapping of disease-specific Oxford Knee Score onto EQ-5D-5L utility index in knee osteoarthritis.

BACKGROUND: EQ5D is a generic measure of health. It provides a single index value for health status that can be used in the clinical and economic evaluation of healthcare. Oxford Knee Score (OKS) is a joint-specific outcome measure tool designed to assess symptoms and function in osteoarthritis patients after joint replacement surgery. Though widely used, it has the disadvantage of lacking health index value. To fill the gap between functional and generic questionnaires with economic value, we linked generic EQ-5D-5L to the specific OKS to give a single index value for health status in KOA patients. QUESTIONS/PURPOSES: Developing and evaluating an algorithm to estimate EuroQoL generic health utility scores (EQ-5D-5L) from the disease-specific OKS using data from patients with knee osteoarthritis (KO). PATIENTS AND METHODS: This is a cross-sectional study of 571 patients with KO. We used four distinct mapping algorithms: Cumulative Probability for Ordinal Data, Penalized Ordinal Regression, CART (Classification and Regression Trees), and Ordinal random forest. We compared the resultant models' degrees of accuracy. RESULTS: Mobility was best predicted by penalized regression with pre-processed predictors, usual activities by random forest, pain/discomfort by cumulative probability with pre-processed predictors, self-care by random forest with RFE (recursive feature elimination) predictors, and anxiety/depression by CART with RFE predictors. Model accuracy was lowest with anxiety/depression and highest with mobility and usual activities. Using available country value sets, the average MAE was 0.098 ± 0.022, ranging from 0.063 to 0.142; and the average MSE was 0.020 ± 0.008 ranging from 0.008 to 0.042. CONCLUSIONS: The current study derived accurate mapping techniques from OKS to the domains of EQ-5D-5L, allowing for the computation of QALYs in economic evaluations. A machine learning-based strategy offers a viable mapping alternative that merits further exploration.

Validation and Cross-Cultural Adaptation of the Hindi Version of the Oxford Knee Score in Patients With Knee Osteoarthritis.

INTRODUCTION: Cases of knee osteoarthritis are on the rise in India with an increasingly ageing population. A large number among them shall undergo total knee replacement, so there is a requirement for validated patient-reported outcome measures in the Hindi language. Oxford Knee Score (OKS) is one of the most commonly used patient-reported outcome measure scoring systems. The current study was designed to test and validate cross-cultural adaptation and translate the Hindi version of the Oxford Knee Score (OKS-H).  Material and Methods: The OKS-H was formulated as per recommendations for cross-cultural adaptation and translation. The OKS was tested on 162 patients with knee osteoarthritis who underwent a total knee replacement. Reliability of the OKS-H was tested using the intraclass correlation coefficient (ICC) and internal consistency was assessed using Cronbach's alpha. The construct validity was assessed using OKS-H, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and 36-Item Short Form Survey (SF-36) questionnaire.  Results: The translation was performed with no major difficulty. The OKS was completed by 158 (97.5%) and 157 (96.9%) patients at test and retest, respectively, after one week. With an ICC of 0.87, OKS had shown good reliability. The construct validity obtained against the WOMAC and SF-36 scores was strong (ICC between 0.49 to 0.86). CONCLUSION: The translated OKS-H is a reliable and valid instrument for patient-reported outcome measures in cases of knee osteoarthritis opting for total knee arthroplasty.

Influence of vitamin D levels on outcomes and nosocomial COVID-19 infection in patients undergoing total knee arthroplasty- a cohort study.

Purpose: This study aimed to audit the effects of vitamin D3 on the early functional outcomes, the incidence of nosocomial COVID-19 infection and complications in patients undergoing elective Total Knee Arthroplasty (TKA). Methods: This was a retrospective study involving patients undergoing primary unilateral TKA between January 2020 to May 2021 operated by a single surgeon using a single implant. Participants were divided into two cohorts, Deficient-vitamin D3 level <20 ng/ml and Sufficient-vitamin D3 level ≥20 ng/ml. Assessment for Knee Society Score and Oxford Knee Score (OKS) was done preoperatively and one year after TKA. Nosocomial COVID-19 infection rate, 30-day re-admissions and complications were noted during the study. Results: 235 patients were divided into 2 cohorts matched by age, gender and ASA grades. 74 patients belonged to the deficient group and 161 belonged to the sufficient group. The mean preoperative scores in the sufficient group were higher than the deficient group (OKS = 15.74 vs 12.95; KSS = 88.91vs 85.62). Similarly, the one-year postoperative scores in the sufficient group were significantly higher (OKS = 36.54 vs 35.16; KSS = 164.01 vs 161.22). A linear correlation was present between preoperative score (r = 0.273) & post-operative scores (r = 0.141) with serum vitamin D3 levels. Vitamin D3 deficient individuals had higher nosocomial COVID-19 infection rate (10.81% vs 4.96%,p = 0.16). The incidence of complications like DVT, embolism, stroke, infection and fracture were not statistically different in the two groups. Conclusion: Vitamin D positively influences the outcomes of TKA and protects against nosocomial COVID-19 infection in patients undergoing elective TKA.

Oxford Knee Score and EQ-5d poorly predict patient's satisfaction following mechanically aligned total knee replacement: A cross-sectional study.

BACKGROUND: Patient satisfaction is increasingly used to measure the success of arthroplasty. Satisfaction with the outcome of a total knee replacement (TKR) is traditionally thought to be associated with improvements in functional status and quality of life measures. This study aims to answer the following questions: 1. What is the level of patient satisfaction, improvement in knee function and patient quality of life associated with mechanically aligned TKR? 2. What is the relationship between OKS, EQ-5d scores and 'outcome satisfaction'? HYPOTHESIS: TKR is associated with a significant improvement in function, satisfaction and quality of life and that there is a strong correlation between OKS, EQ-5d and 'outcome satisfaction'. METHOD: Five thousand eight hundred and ninety six patients underwent primary TKR between January 2010 and December 2017 and had complete preoperative and 2-year follow-up data for OKS, EQ-5d and satisfaction scores. Outcomes data were collected prospectively and recorded on our institutional database. Minimal clinically important difference (MCID) and the Patient acceptable symptomatic state (PASS) were calculated for OKS and EQ-5d, the association between OKS, EQ-5d and 'outcome satisfaction' was measured using regression analysis. RESULTS: The median 2-year 'outcome satisfaction' score was 90/100 with 79% of patients reporting excellent satisfaction (≥80/100) and 93.4% of patients satisfied (≥50/100). Postoperatively, median scores were 39 for OKS and 0.8 for EQ-5d. The mean increase in scores was 15.85 for OKS and 0.32 for EQ-5d. Satisfaction showed moderate positive correlation with postoperative OKS (r=0.69) and EQ-5D (0.58) scores, but weaker correlation with the change in OKS (r=0.57) and EQ-5d (r=0.32) scores from preoperative levels. DISCUSSION/CONCLUSION: Mechanically aligned TKR is overall a successful operation responsible of fair rate of patient satisfaction. OKS and EQ-5d are imperfect predictors for satisfaction as they are significantly influenced by patients' comorbidities. This should be taken into account when evaluating the success of an operation. LEVEL OF EVIDENCE: IIc; observational study (based on prospectively collected data from an institutional registry).

The ceiling effects of patient reported outcome measures for total knee arthroplasty.

BACKGROUND: Patient reported outcome measurements (PROMs) that exhibit a substantial ceiling effect show clustering of participant's scores towards the upper limit of a scale and consequently have low discriminatory power among high end scores. This study aimed to compare ceiling effects at 1 and 2 years postoperatively across commonly usedPROMs for TKA. HYPOTHESIS: We hypothesized, that the analyzed PROMs differ substantially in regards to their ceiling effect. PATIENTS AND METHODS: Patients that underwent a primary unilateral TKA and completed pre-operative and post-operative questionnaires were included in the analysis. Participants completed the KOOS, KOOS-12, KOOS-JR, KOOS-PS, WOMAC and OKS preoperatively, and completed the KOOS, KOOS-12, KOOS-JR, KOOS-PS, WOMAC,OKS and FJS postoperatively at 1 and 2 years. RESULTS: 1-year and 2-year follow-up data was available for 380 and 193 patients, respectively. The preoperative mean age was 68.0 (8.5) and mean BMI was 31.4kg/m2 (6.6), with a male to female ratio of 49.6% to 50.4%. At 1 year postoperatively, a ceiling effect was seen for the Pain and ADL subscales of the KOOS and the KOOS JR. The KOOS Pain, Symptoms, ADL and QoL subscales, the WOMAC Total and KOOS JR exhibited a ceiling effect at 2 years postoperatively. We found 9.0% and 14.8% of patients achieving a maximum score in the FJS at 1 and 2 years, respectively, indicating the absence of a substantial ceiling effect. CONCLUSION: The PROMs studied differ substantially with regards to their ceiling effect and consequently their ability to detect differences between well performing groups. The KOOS Pain, Symptoms, ADL and QoL subscales, the WOMAC Total and KOOS JR exhibited a substantial ceiling effect at 2 years postoperatively. We recommend using PROMs like the FJS and KOOS-12 with a more evenly distribution of scores across the scale when studying well performing cohorts. LEVEL OF EVIDENCE: III.

Assessing responsiveness of the EQ-5D-3L, the Oxford Hip Score, and the Oxford Knee Score in the NHS patient-reported outcome measures.

BACKGROUND: The degree to which a validated instrument is able to detect clinically significant change over time is an important issue for the better management of hip or knee replacement surgery. This study examines the internal responsiveness of the EQ-5D-3L, the Oxford Hip Score (OHS), and the Oxford Knee Score (OKS) by various methods. Data from NHS patient-reported outcome measures (PROMs) linked to the Hospital Episodes Statistics (HES) dataset (2009-2015) was analysed for patients who underwent primary hip surgery (N = 181,424) and primary knee surgery (N = 191,379). METHODS: Paired data-specific univariate responsiveness was investigated using the standardized response mean (SRM), the standardized effect size (SES), and the responsiveness index (RI). Multivariate responsiveness was furthermore examined using the defined capacity of benefit score (i.e. paired data-specific MCID), adjusting baseline covariates such as age, gender, and comorbidities in the Box-Cox regression models. The observed and predicted percentages of patient improvement were examined both as a whole and by the patients' self-assessed transition level. RESULTS: The results showed that both the OHS and the OKS demonstrated great univariate and multivariate responsiveness. The percentages of the observed (predicted) total improvement were high: 51 (54)% in the OHS and 73 (58)% in OKS. The OHS and the OKS showed distinctive differences in improvement by the 3-level transition, i.e. a little better vs. about the same vs. a little worse. The univariate responsiveness of the EQ-5D-3L showed moderate effects in total by Cohen's thresholds. The percentages of improvement in the EQ-5D-3L were moderate: 44 (48)% in the hip and 42 (44)% for the knee replacement population. CONCLUSIONS: Distinctive percentage differences in patients' perception of improvement were observed when the paired data-specific capacity of benefit score was applied to examine responsiveness. This is useful in clinical practice as rationale for access to surgery at the individual-patient level. This study shows the importance of analytic methods and instruments for investigation of the health status in hip and/or knee replacement surgery. The study finding also supports the idea of using a generic measure along with the disease-specific instruments in terms of cross-validation.

Safety and efficacy of sequential simultaneous bilateral total knee arthroplasty: A single centre retrospective cohort study.

BACKGROUND: Simultaneous bilateral total knee arthroplasty (TKA) is a promising option for patients with bilateral arthritis of the knee because of the requirement of a single hospitalization and anesthetic regimen, reduced overall hospital stay, lower overall costs, and quicker recovery compared to staged bilateral TKA. However, there are conflicting reports on the safety of the procedure, with little data available in the Indian setting. Herein, we compared the efficacy and safety of sequential simultaneous bilateral TKA (SSBTKA) with those of unilateral TKA (UTKA). METHODS: This retrospective analysis included cases of SSBTKA (n = 380, 760 knees) and UTKA (n = 754) performed by the same surgeon and followed up for a minimum duration of 1 year. The functional outcomes (postoperative changes in Oxford Knee Score [OKS] and Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]), length of hospital stay (LOS), complications, and rates of revision and mortality were compared between the two groups. RESULTS: The mean follow-up durations were 40.59 and 36.69 months for the UTKA and SSBTKA groups, respectively. The LOS was significantly longer in the SSBTKA group than in the UTKA group (Median [Interquartile range]: 4[1] vs. 3[0], p < 0.001). The OKS and WOMAC scores increased with time in both groups. The improvements in each of these scores at 3, 6, and 12 months postoperatively were either statistically similar between the two groups or, if statistically different, the differences were too small to be clinically meaningful. Blood transfusions (4% [SSBTKA] vs.0.3% [UTKA], p < 0.001), cardiac complications (1.6% vs. 0.4%, p = 0.034), urine retention (3.7% vs. 1.2%, p = 0.005), and deep infection (0.8% vs. 0%, p = 0.015) were significantly more frequent in the SSBTKA group. None of the patients in the UTKA group had to undergo revision surgery, whereas in the SSBTKA group, 2 (0.6%) patients underwent revision TKA. The overall mortality rates were low in both groups (0.8% [SSBTKA] and 0.3% [UTKA]), with no significant between-group difference (p = 0.209). CONCLUSION: The functional outcomes and mortality rates associated with SSBTKA are comparable to those associated with UTKA. The risk of complications and the need for revision, although higher with SSBTKA, the actual numbers are low enough to justify its use. Although the LOS in SSBTKA is longer than that in UTKA, it is likely to be shorter than the cumulative LOS for two UTKA procedures (i.e. a staged bilateral TKA). Thus, SSBTKA appears to be a safe and effective choice for appropriately selected patients.

Predicting patient reported outcome in total knee arthroplasty using body mass index and limb measurements.

BACKGROUND: Body mass index (BMI) has not been shown to correlate with Patient Reported Outcome Measures (PROMs) following total knee arthroplasty (TKA). We investigated the relationship between weight, BMI, limb morphology, and Oxford Knee Score (OKS). Furthermore, the utility of a novel radiological measurement, the Knee Mass Index (KMI), was investigated. METHODS: Data including weight, BMI, gender, preoperative and 12 month OKS were collected from an arthroplasty database that contained 268 patients who underwent TKA. Measurements of soft tissue and bone width were made from the preoperative radiograph and 'KMI' was calculated. Pearson correlation and multivariate regression analyses were used to assess the relationship between OKS and the above variables. RESULTS: The novel measurement, KMI, was not a predictor of the OKS. The BMI was predictive of initial OKS (Odds Ratio (OR) -0.26 p < 0.001), 12 month OKS (OR -0.39 p < 0.001) and change in OKS (OR -0.39 p < 0.001). The initial OKS was predictive of 12 month OKS (OR 0.32 p < 0.001) and change in OKS (OR -0.68 p < 0.001). CONCLUSIONS: The novel KMI metric was not useful in predicting function. Both the post-operative OKS and change in OKS are predicted by BMI and pre-operative OKS. This is one of the first studies to show a relationship between BMI and OKS.