What makes patients aware of their artificial knee joint?

Meteoropathy: a review on the current state of knowledge

Meteoropathy is no longer considered a popular myth, but a new disease that significantly impacts daily life, particularly in individuals who experience mental illness, cardiovascular disorders, and respiratory conditions. However, there are very limited data on this condition. This study aimed to comprehensively review and analyze existing in vivo animal studies and human clinical trials investigating the effects of meteoropathy on health and its pharmacological treatment. A thorough literature search was conducted across databases such as PubMed and Scopus to gather relevant information. Our analysis primarily focused on the relationship between meteoropathy and mental health, including the influence on affective temperaments. Additionally, we explored various treatment approaches, emphasizing the combination of muscle exercises, pharmacological interventions, and naturopathy, which have shown promise in alleviating pain among individuals affected by meteoropathy. Future research in meteoropathy should shed light on synthesizing new pharmacological compounds.

Unicompartmental Knee Arthroplasty Patients Have Lower Joint Awareness and Higher Function at 5 Years Compared to Total Knee Arthroplasties: A Matched Comparison

BACKGROUND

The purpose of this study was to evaluate postoperative outcomes at minimum 5-year follow-up in patients following unicompartmental knee arthroplasty (UKA) compared to a matched cohort of total knee arthroplasty (TKA) patients.

METHODS

Patients who had primarily medial compartment osteoarthritis (OA) who met criteria for medial UKA underwent TKA or medial UKA between 2014 and 2015 at a single institution, matched for age, sex, and body mass index. There were 127 UKAs in 120 patients and 118 TKAs in 116 patients included with minimum 5-year follow-up (range, 6 to 8). Mean age was 69 years (range, 59 to 79) and 71 years (range, 62 to 80) in the UKA and TKA groups, respectively (P = .049).

RESULTS

Patients who underwent UKA had significantly higher mean (±SD) Forgotten Joint Scores (87 ± 20 versus 59 ± 34, P < .001); higher Knee Society Scores (88 ± 14 versus 75 ± 21, P < .001); and lower Numeric Pain Rating Scores (0.8 ± 1.6 versus 1.9 ± 2.2, P < .001). Survivorship free from all-cause revision was 96% (95% CI = 93%-99%) and 99% (95% CI = 97%-100%) at 5 years for TKA and UKA, respectively (P = .52). There were 8 both component revisions in the TKA group within 5 years from the date of surgery and 2 UKA conversions to TKA after 5-year follow-up.

CONCLUSION

Patients who have medial compartment OA and underwent UKA had significantly lower joint awareness, decreased pain, improved function, and higher satisfaction compared to matched TKA patients at minimum 5-year follow-up while maintaining excellent survivorship.

Is 2-Stage Septic Revision Worth the Money? A Cost-Utility Analysis of a 1-Stage Versus 2-Stage Septic Revision of Total Knee Arthroplasty

BACKGROUND

Two-stage exchange arthroplasty remains the gold standard for the management of prosthetic joint infection (PJI) of the knee, but several studies have demonstrated that 1-stage exchange is as effective as 2-stage exchange. This study aimed to support decision-making via an economic evaluation of 1-stage compared to 2-stage exchange for total knee arthroplasty septic revision in patients who did not have compelling indication PJI (ie, Methicillin-resistant Staphylococcus aureus, multiorganism, systemic sepsis, comorbidities, culture negative, resistant organism, and immunocompromised) to undergo a 2-stage exchange.

METHODS

A cost-utility analysis was performed using a Markov cohort model from the health care provider perspective using Australia data. One-stage septic knee revisions were compared with 2-stage exchange procedures for chronic PJI using a patient-lifetime horizon. Health outcomes were expressed as quality-adjusted life-years (QALY), whereas costs were presented in 2020 Australian dollars. Sensitivity analyses, population expected values of perfect information, and the perfect information for parameters (EVPPI) were assessed to estimate the opportunity costs surrounding the decision made at a willingness-to-pay threshold of $50,000 per QALY.

RESULTS

The incremental cost-effectiveness ratio of 2-stage exchange compared with 1-stage exchange was $231,000 per QALY, with 98.5% of the probabilistic sensitivity simulations above the willingness-to-pay threshold. The population expected value of perfect information was $882,000, whereas the expected value of perfect information for parameters for the "cost parameters" was $207,000.

CONCLUSION

The adoption of 1-stage septic knee revision is the optimal choice for patients who have a PJI and who do not have a compelling need for a 2-stage exchange arthroplasty. One-stage exchange for PJI should be advocated in patients who meet the eligibility criteria.

Detecting the Effect Size of Weather Conditions on Patient-Reported Outcome Measures (PROMs)

One of the next frontiers in medical research, particularly in orthopaedic surgery, is personalized treatment outcome prediction. In personalized medicine, treatment choices are adjusted for the patient based on the individual's and their disease's distinct features. A high-value and patient-centered health care system requires evaluating results that integrate the patient's viewpoint. Patient-reported outcome measures (PROMs) are widely used to shed light on patients' perceptions of their health status after an intervention by using validated questionnaires. The aim of this study is to examine whether meteorological or light (night vs. day) conditions affect PROM scores and hence indirectly affect health-related outcomes. We collected scores for PROMs from questionnaires completed by patients (N = 2326) who had undergone hip and knee interventions between June 2017 and May 2020 at the IRCCS Orthopaedic Institute Galeazzi (IOG), Milan, Italy. Nearest neighbour propensity score (PS) matching was applied to ensure the similarity of the groups tested under the different weather-related conditions. The exposure PS was derived through logistic regression. The data were analysed using statistical tests (Student's t-test and Mann-Whitney U test). According to Cohen's effect size, weather conditions may affect the scores for PROMs and, indirectly, health-related outcomes via influencing the relative humidity and weather-related conditions. The findings suggest avoiding PROMs' collection in certain conditions if the odds of outcome-based underperformance are to be minimized. This would ensure a balance between costs for PROMs' collection and data availability.

Patient perspectives of pain and function after knee replacement: a systematic review and meta-synthesis of qualitative studies

Introduction

Joint replacement surgery typically results in good clinical outcome, although some people experience suboptimal pain relief and functional improvement. Predicting surgical outcome is difficult.

Objectives

There is merit in better understanding patients' perspectives of pain and function to identify avoidable problems perceived to contribute to their outcome, to inform prognostic expectations, and to identify potential cointerventions to sit alongside surgery that might mitigate pain/functional problems. Here, we aimed to synthesise the available literature exploring perspectives of people with knee osteoarthritis about their pain and function following joint replacement.

Methods

Six electronic databases and 2 websites were searched. Two independent reviewers completed study inclusion, quality assessment, and data extraction. Data were iteratively synthesised using first-, second-, and third-order analyses.

Results

Twenty-eight studies were included. Four themes were identified; perceptions of pain and function were inseparable. Theme 1 addressed experiences of recovery after surgery, which often differed from expectations. Theme 2 described the challenges of the pain experience and its functional impact, including the difficulty navigating medication use in context of personal beliefs and perceived stigma. Theme 3 articulated the toll of ongoing problems spanning pain-function-mood, necessitating the need to "endure." Theme 4 encompassed the importance of clinical/social interactions on mood and pain, with reports of concerns dismissed and practical support missing.

Conclusions

Together, these findings show that numerous individual considerations beyond the technical aspects of surgery influence experiences of pain and function. A tailored approach addressing these considerations from the patient perspective could provide a basis for improved success of knee replacement surgery.

Joint awareness after unicompartmental and total knee arthroplasty: Which feels more natural?

Background/Purpose

The purpose of this study was to compare the joint awareness and knee function after unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) for the management of isolated medial compartment osteoarthritis.

Methods

Patients who underwent UKA or TKA at our institution for isolated medial compartment osteoarthritis from 2015 to 2020 with a minimum follow-up of 1 year were screened. 116 eligible patients were invited and 94 volunteer patients participated. All patients were evaluated with The Forgotten Joint Score-12 and Lysholm Knee Scale.

Results

Average follow-up period was 29.13±15.48 months for UKA and 31.66±2.91 months for TKA groups ( p=0.292). FJS-12 of the UKA group was significantly higher than that of the TKA group (79.74±15.06 and 63.25±19.86, respectively; p=0.024). The Lysholm Knee Scale score was also significantly higher in the UKA group compared with the TKA group (92.94±8.74 and 78.34±14.99, respectively; p = 0.002).

Conclusion

Our findings suggest that patients who underwent UKA were less aware of their artificial joints and had better knee function compared to patients who underwent TKA for medial osteoarthritis of the knee.

3D Puzzle in Cube Pattern for Anisotropic/Isotropic Mechanical Control of Structure Fabricated by Metal Additive Manufacturing

Metal additive manufacturing is a powerful tool for providing the desired functional performance through a three-dimensional (3D) structural design. Among the material functions, anisotropic mechanical properties are indispensable for enabling the capabilities of structural materials for living tissues. For biomedical materials to replace bone function, it is necessary to provide an anisotropic mechanical property that mimics that of bones. For desired control of the mechanical performance of the materials, we propose a novel 3D puzzle structure with cube-shaped parts comprising 27 (3 × 3 × 3) unit compartments. We designed and fabricated a Co–Cr–Mo composite structure through spatial control of the positional arrangement of powder/solid parts using the laser powder bed fusion (L-PBF) method. The mechanical function of the fabricated structure can be predicted using the rule of mixtures based on the arrangement pattern of each part. The solid parts in the cubic structure were obtained by melting and solidifying the metal powder with a laser, while the powder parts were obtained through the remaining nonmelted powders inside the structure. This is the first report to achieve an innovative material design that can provide an anisotropic Young’s modulus by arranging the powder and solid parts using additive manufacturing technology.

Meaningful values in the Forgotten Joint Score after total knee arthroplasty

AIMS

The aim of this study was to identify the minimal clinically important difference (MCID), minimal important change (MIC), minimal detectable change (MDC), and patient-acceptable symptom state (PASS) threshold in the Forgotten Joint Score (FJS) according to patient satisfaction six months following total knee arthroplasty (TKA).

METHODS

During a one-year period 484 patients underwent a primary TKA and completed preoperative and six-month FJS and OKS. At six months patients were asked, "How satisfied are you with your operated knee?" Their response was recorded as: very satisfied, satisfied, neutral, dissatisfied, or very dissatisfied. The difference between patients recording neutral (n = 44) and satisfied (n = 153) was used to define the MCID. MIC for a cohort was defined as the change in the FJS for those patients declaring their outcome as satisfied, whereas receiver operating characteristic curve analysis was used to determine the MIC for an individual and the PASS threshold. Distribution-based methodology was used to calculate the MDC.

RESULTS

Using satisfaction as the anchor question, the MCID for the FJS was 16.6 (95% confidence interval (CIs) 8.9 to 24.3; p < 0.001) and when adjusting for confounding this decreased to 13.7 points (95% CI 4.8 to 22.5; p < 0.001). The MIC for the FJS for a cohort of patients was 17.7 points and for an individual patient was 10 points. The MDC90 for the FGS was 12 points; where 90% of patients scoring more than this will have experienced a real change that is beyond measurement error. The PASS was defined as 22 points or more in the postoperative FJS.

CONCLUSION

The estimates for MCID and MIC can be used to assess whether there is clinical difference between two groups and whether a cohort/patient has had a meaningful change in their FJS, respectively. The MDC90 of 12 points suggests a value lower than this may fall within measurement error. A postoperative FJS of 22 or more was predictive of achieving PASS. Cite this article: Bone Joint J 2021;103-B(5):846-854.

Comparison of Joint Perception Between Posterior-Stabilized and Ultracongruent Total Knee Arthroplasty in the Same Patient

BACKGROUND

Posterior-stabilized and ultracongruent designs are 2 common examples of posterior cruciate ligament-substituting total knee arthroplasty (TKA) prostheses. There is a lack of evidence regarding joint perception differences between ultracongruent and posterior-stabilized TKA. The purpose of this study was to compare the postoperative knee stability, function, and joint perception between ultracongruent and posterior-stabilized TKA in the same patients in order to determine whether there was a difference based on design.

METHODS

This prospective, randomized controlled trial included 50 patients who underwent same-day bilateral TKA utilizing Persona (Zimmer Biomet) posterior-stabilized implants in 1 knee (posterior-stabilized group) and ultracongruent implants in the other knee (ultracongruent group). At 2 years postoperatively, patients were evaluated for knee stability, function, and joint perception. Postoperative static knee anteroposterior stability and femoral rollback were compared. Knee function was evaluated with use of the Knee Society Score and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Joint perception was compared by evaluating noise generation, side preference, satisfaction, and the Forgotten Joint Score.

RESULTS

The ultracongruent group had more knee anteroposterior laxity (4.5 mm compared with 1.8 mm in the posterior-stabilized group; p < 0.001) and less femoral rollback (4.2 mm compared with 9.0 mm in the posterior-stabilized group; p < 0.001). Knee Society Score and WOMAC scores were not significantly different between groups (all p > 0.05). Although the ultracongruent group showed less noise generation than the posterior-stabilized group (18% compared with 38%, respectively; p = 0.026), there were no differences in side preference, satisfaction, or Forgotten Joint Score (all p > 0.05).

CONCLUSIONS

Both groups had similar joint perception 2 years postoperatively, with obvious differences in noise generation and more sagittal laxity with less femoral rollback in the ultracongruent group.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Translation and Validation of Forgotten Joint Score for Total Hip Arthroplasty for Indian Population

BACKGROUND

The ultimate success of a total hip replacement lies in patients forgetting about their artificial joints during routine activities. "Forgotten Joint Score (FJS)" is emerging as an important tool in assessing outcomes of total hip arthroplasty. There has been no version of this score available in commonly spoken vernaculars in India. This study aims to formulate and validate the Hindi version of FJS in Indian population.

METHODS

A total of 136 patients with a minimum follow-up of 6 months and a maximum follow-up of 18 months after total hip arthroplasty were asked to fill the translated and adapted version of FJS questionnaire, at two points of time 2 weeks apart. The Hindi version of FJS (I-FJS) was tested for reliability and responsiveness, floor and ceiling effect and validity against modified Harris Hip Score (mHHS). Construct validity was expressed as the Pearson correlation coefficient. Internal consistency was expressed as Cronbach's alpha and test-retest reliability as the intra-class correlation coefficient (ICC).

RESULTS

I-FJS showed excellent internal consistency with Cronbach's alpha of 0.88. Intra-class correlation coefficient (ICC) was 0.94. I-FJS showed good correlation with m-HHS (r = 0.8, p = 0.001). The standard error of measurement was 3.6 and the smallest detectable change was 9.97. There was no floor or ceiling effect observed with I-FJS. Data from this study were insufficient to establish adequate responsiveness of I-FJS.

CONCLUSION

I-FJS is a valid, reliable and reproducible score for hip function in post-THA patients. It is devoid of any floor or ceiling effect. Hindi version of FJS could be an effective tool for studying hip function in the Indian population.

Affordance-Based Surgical Design Methods Considering Biomechanical Artifacts

Surgical design in personalized medicine is often based on native anatomy, which may not accurately reflect the interaction between native musculoskeletal tissues and biomechanical artifacts. To overcome this problem, researchers have developed alternative methods based on affordance-based design. The design process can be viewed in terms of action possibilities provided by the (biological) environment. Here, we use the affordance-based approach to address possibilities for action offered by biomechanical artifacts. In anterior crucial ligament (ACL) reconstruction, the design goal is to avoid ligament impingement while optimizing the placement of the tibial tunnel. Although in the current rationale for tibial tunnel placement roof impingement is minimized to avoid a negative affordance, we show that tibial tunnel placement can rather aim to constrain the target bounds with respect to a positive affordance. We describe the steps for identifying the measurable invariants and provide a mathematical framework for the surgery affordances within the knee.

Titanium-Nitride Coating Does Not Result in a Better Clinical Outcome Compared to Conventional Cobalt-Chromium Total Knee Arthroplasty after a Long-Term Follow-Up: A Propensity Score Matching Analysis

Background: The impact of titanium nitride (TiN) coating on implant components is controversial. TiN coating is proposed as having superior biomechanical properties compared to conventional cobalt-chromium (CoCr) alloy. This study compared long-term clinical data as well as meteoro-sensitivity in patients who underwent total knee arthroplasty (TKA), with either CoCr alloy or TiN coating. Methods: In this retrospective observational study, the clinically approved cemented “low contact stress” (LCS) TKA with conventional CoCr coating, was compared to un-cemented TiN-coated “advanced coated system” (ACS) TKA. Propensity score matching identified comparable patients based on their characteristics in a one-to-one ratio using the nearest-neighbor method. The final cohort comprised 260 knees in each cohort, with a mean follow-up of 10.1 ± 1.0 years for ACS patients and 14.9 ± 3.0 years for the LCS group. Physical examinations, meteoro-sensitivity, and knee scoring were assessed. Results: The clinical and functional Knee Society Score (KSS) (82.6 vs. 70.8; p < 0.001 and 61.9 vs. 71.1; p = 0.011), the postoperative Visual Analogue Scale (VAS) (2.9 vs. 1.4; p = 0.002), and the postoperative Tegner Score (2.6 vs. 2.2; p = 0.001) showed significant intergroup differences. The postoperative Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC) was similar (79.9 vs. 81.3; p = 0.453) between groups. Meteoro-sensitivity of the artificial joint was significantly more prevalent in the ACS patient cohort (56% vs. 23%; p < 0.001). Conclusion: This study suggests that TiN coating does not provide improved clinical outcomes in this patient cohort after a long-term follow-up. Interestingly, sensitivity to weather changes were more correlated with un-cemented ACS implants.

The Forgotten Joint Score-12 as a valuable patient-reported outcome measure for patients after first-time patellar dislocation

BACKGROUND

The aim of this study is to assess joint awareness after first-time patellar dislocation using the Forgotten Joint Score-12 (FJS-12) and to compare performance of this measurement tool to acknowledged patient-reported outcome scores.

METHODS

A retrospective analysis of patients with confirmed first-time patellar dislocation was performed. Patients were assessed with the FJS-12, the Kujala and the WOMAC scores. Reference values for the FJS-12 were obtained from a matched healthy control group with no history of previous knee joint pathology. We calculated Cronbach's alpha, assessed the ceiling effect for all scores, and calculated the Spearman correlation coefficient between them RESULTS: Fifty-six patients (mean follow-up 8.2 years, range 1.6-14.1) with a mean age of 26.4 years were analysed. Compared with the age- and gender-matched control group, the patellar dislocation group showed significantly lower (worse) mean FJS-12 scores (88 vs. 71, P < 0.001). Inter-score correlation between the FJS-12 and the Kujala was high (r = 0.74) and significant (P < 0.001), as well as between FJS-12 and WOMAC (r = 0.81, P < 0.001). Cronbach's alpha of the FJS-12 was 0.92 (95% confidence interval 0.90-0.94). The FJS-12 showed less ceiling effect (16%) compared with the Kujala score (23%) and the WOMAC score (32%).

CONCLUSIONS

The concept of joint awareness has been successfully applied to a patient population after patellar dislocation. The FJS-12 showed less ceiling effect compared with the Kujala and the WOMAC scores, suggesting the score was able to capture subtle knee problems in patients after patellar dislocation.

Perception of a Natural Joint After Total Knee Arthroplasty

BACKGROUND

Assessing patients' functional outcomes following total knee arthroplasty (TKA) with traditional scoring systems is limited by their ceiling effects. Patient's Joint Perception (PJP) question of the reconstructed joint is also of significant interest. Forgotten Joint Score (FJS) was created as a more discriminating option. The actual score constituting a "forgotten joint" has not yet been defined. The primary objective of this study is to compare the PJP and the FJS in TKA patients to determine the FJS score that corresponds to the patient's perception of a natural joint.

METHODS

One hundred TKAs were assessed at a mean of 40.6 months of follow-up using the PJP question, FJS, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Correlation between the 3 scores and their ceiling effects were analyzed.

RESULTS

With PJP question, 39% of the patients perceived a natural joint (FJS: 92.9; 95% confidence interval [CI], 89.4-96.4), 12% an artificial joint with no restriction (FJS: 79.5; 95% CI, 65.7-93.3), 36% an artificial joint with minor restrictions (FJS: 70.0; 95% CI, 63.2-76.9), and 13% had major restrictions (FJS: 47.3; 95% CI. 32.8-61.7). PJP has a high correlation with FJS and WOMAC (Spearman's rho, -0.705 and -0.680, respectively). FJS and WOMAC had a significant ceiling effect with both reaching the best possible score in >15%.

CONCLUSION

Patients perceiving their TKA as a natural knee based on PJP have a FJS ≥89. PJP has a good correlation with FJS and may be a shorter, simple, and acceptable alternative.

Body-Self Unity With a New Hip or Knee: Understanding Total Joint Replacement Within an Embodiment Framework

Medical research increasingly makes use of embodiment concepts to understand how illness disrupts unity of body and self. However, few have applied embodiment concepts in total joint replacement (TJR), an effective treatment for end‐stage arthritis. In considering why a troubling proportion of TJR recipients have continued pain and functional limitation, we ask: what role might be played by the embodied experience of living with an implant? Relevant theoretical models and prior research on embodiment in musculoskeletal health and transplantation are reviewed. Our findings suggest a research agenda with implications for addressing suboptimal outcomes in TJR.

The Forgotten Joint Score-12 in Swedish patients undergoing knee arthroplasty: a validation study with the Knee Injury and Osteoarthritis Outcome Score (KOOS) as comparator

Background and purpose - Having patients self-evaluate the outcome is an important part of the follow-up after knee arthroplasty. The Forgotten Joint Score-12 (FJS-12) introduced joint awareness as a new approach, suggested to be sensitive enough to differentiate well-functioning patients. This study evaluated the Swedish translation of the FJS-12 and investigated the validity, reliability, and interpretability in patients undergoing knee arthroplastyPatients and methods - We included 109 consecutive patients 1 year after primary knee arthroplasty to assess construct validity (Pearson's correlation coefficient, r), internal consistency (Cronbach's alpha [CA]), floor and ceiling effects, and score distribution. The Knee injury and Osteoarthritis Outcome Score (KOOS) was the comparator instrument for the analyses. Further, 31 patients preoperatively and 22 patients postoperatively were included to assess test-retest reliability (intraclass correlation coefficient [ICC]).Results - Construct validity was moderate to excellent (r = 0.62-0.84). The FJS-12 showed a high degree of internal consistency (CA = 0.96). The ICC was good preoperatively (0.76) and postoperatively (0.87). Ceiling effects were 2.8% in the FJS-12 and ranging between 0.9% and 10% in the KOOS.Interpretation - The Swedish translation of the FJS-12 showed good validity and reliability and can be used to assess outcome after knee arthroplasty. Moreover, the FJS-12 shows promising results in its ability to differentiate well-functioning patients. Future studies on unidimensionality, scale validity, interpretability, and responsiveness are needed for a more explicit analysis of the psychometric properties.

Normative Values for the Forgotten Joint Score-12 for the US General Population

BACKGROUND

The Forgotten Joint Score-12 (FJS-12) is a patient-reported outcome questionnaire of joint awareness in patients with hip and knee pathologies. To improve interpretability of values derived from this measure, we collected normative values for the US general population.

METHODS

A sample of 2000 participants, representative of US general population, was sought via an online panel. Quota sampling was used to obtain age-specific and sex-specific groups of 200 participants each. The FJS-12 is a 12-item questionnaire assessing the ability to forget the hip or knee joint during activities of daily living. To match US national census data from 2010, raking was used for determining data weights.

RESULTS

Normative data for the FJS-12 could be established based on a data set from 2017 respondents (50.1% men; mean age, 54.0 years; 66.3% white/Caucasian). Median FJS-12 scores in the total sample were 75.0 points for knees and 87.5 points for hips. In the age-specific and sex-specific groups, the lowest median score for knees was 54.2 points (men aged 18-39 years) and the highest median was 97.0 (men aged above 70 years). Similarly, median scores for hips were lowest in men aged 18-39 years (60.9 points) and highest in men aged above 70 years (100 points).

CONCLUSION

Normative values have been established for the FJS-12 for hips and knees in US general population. Age-specific and sex-specific differences require relying on normative values from the respective groups when interpreting FJS-12 data.

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.