Validation and interval scale transformation of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) in patients undergoing knee arthroplasty, using the Rasch model

Expectation fulfillment is associated with good outcomes and patient satisfaction after knee arthroplasty: a prospective study in a multi-ethnic Asian population

We aimed to evaluate the relationship between patient expectations and outcomes after knee arthroplasty (KA) in an Asian population in Singapore. We recruited consecutive patients with severe knee osteoarthritis (KOA) scheduled for KA. Pre-operatively, patients provided socio-demographic data and completed the Hospital for Special Surgery Knee Replacement Expectations Survey (HSS-KRES) for baseline pre-operative expectations and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) for baseline pain and function. Telephone interviews were conducted at 6- and 12-months post-operatively to collect the WOMAC, satisfaction with KA, and the extent to which pre-operative expectations had been fulfilled. We included 1136 patients (mean age 65.9 years, 69.9% female), of which 1103 and 1089 completed the telephone interviews at 6- and 12-months post-KA respectively. In the multivariable models, expectation fulfilment was consistently associated with improvements in WOMAC pain and function at 6- and 12-months post-operatively, but not the baseline expectations. In the sensitivity analyses, expectation fulfilment was also found to be significantly associated with the achievement of minimal clinically important difference (MCID) for WOMAC pain and function at both 6- and 12-months. Expectation fulfilment was associated with patient satisfaction in the adjustment models at both 6- and 12-months after KA. The fulfilment of expectations, rather than pre-operative expectations, is associated with improvements in WOMAC pain, function and overall satisfaction at 6- and 12-months after KA.

Image-based robotic (ROSA® knee system) total knee arthroplasty with inverse kinematic alignment compared to conventional total knee arthroplasty : Study protocol and the inverse kinematic alignment in 8-steps using the ROSA® Knee system for knee balancing technique explained

INTRODUCTION

In 2020, 368 million people globally were affected by knee osteoarthritis, and prevalence is projected to increase with 74% by 2050. Relatively high rates of dissatisfactory results after total knee arthroplasty (TKA), as reported by approximately 20% of patients, may be caused by sub-optimal knee alignment and balancing. While mechanical alignment has traditionally been the goal, patient-specific alignment strategies are gaining interest. Robotic assistance could potentially facilitate implementation of these alignment strategies through data-based surgical planning, accurate execution of the surgical plan and validation. The clinical value of surgical assistance in diverging from mechanical alignment remains to be investigated. In the present study, robotic-assisted TKA will be performed to pursue inverse kinematic alignment (iKA) within predefined boundaries, focusing on restoring native tibia joint line.

METHODS

This randomized controlled trial evaluates clinical effectiveness of robotic-assisted TKA (ROSA® Knee System, Zimmer Biomet, Montreal, Quebec, Canada) aiming for iKA compared to conventional TKA aiming for mechanical alignment. A total of 150 participants will be randomized (1:1) to either treatment to provide an 80% power for a 4.8-point clinically important difference in the primary outcome measure, the Oxford Knee Score (OKS) 12 months after surgery. Allocation was achieved using computer-based randomization. Outcomes will be analyzed using linear mixed models with time and group as main factors and interaction-term. Secondary outcomes include clinical metrics (leg alignment, implant and patient survival), surgical parameters (adverse events, surgery duration, blood loss, hospital stay length, medication use), patient-reported outcomes (symptoms, quality of life, pain), mobility and physical activity measurements, metabolic syndrome, cost-efficacy, and gait and continuous glucose monitoring.

ETHICS AND DISSEMINATION

This study has been approved by the Medical Ethical Committee Zuyd and Zuyderland Medical Centre (NL79161.096.21/METCZ20220006), September 2022.

TRIAL REGISTRATION NUMBER

NCT05685693 (clinicaltrials.gov).

Efficacy, Safety, and Tolerability of a Very Low-Calorie Ketogenic Diet in Women with Obesity and Symptomatic Knee Osteoarthritis: A Pilot Interventional Study

BACKGROUND/OBJECTIVES

Obesity is a major risk factor for knee osteoarthritis (OA), and weight loss is crucial for its management. This pilot study explores the effects of a Very Low-Calorie Ketogenic Diet (VLCKD) in women with obesity and symptomatic knee OA.

METHODS

Women with symptomatic knee OA and obesity, defined as a body mass index (BMI) ≥ 30 kg/m2, were eligible for the VLCKD protocol. The intervention included a ketogenic phase from baseline (T0) to the 8th week (T8), followed by a progressive reintroduction of carbohydrates over the next 12 weeks, ending at the 20th week (T20). Body mass index (BMI), the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index, the EuroQol 5D (EQ-5D), and the 36-item Short Form Health Survey (SF-36) were assessed at all time points. Generalized estimating equations were used to analyze the association between BMI and patient-reported outcomes across the study period.

RESULTS

Twenty participants started the study, but four discontinued the intervention, with two of these being due to adverse effects. The mean age of the 16 patients who completed the 20-week program was 57.3 ± 5.5 years, and their mean BMI was 40.0 ± 4.8 kg/m2. The mean BMI significantly decreased to 37.5 ± 4.5 at T4, 36.3 ± 4.6 at T8, and 34.8 ± 4.8 at T20 (all p < 0.001 compared to baseline). The total WOMAC score improved from a mean of 43.6 ± 16.9 at T0 to 30.2 ± 12.8 at T4 (p = 0.005) and further to 24.7 ± 10.6 at T8 (p = 0.001) and to 24.8 ± 15.9 at T20 (p = 0.005). The reduction in BMI was significantly correlated with the improvements in WOMAC, EQ-5D, and SF-36 over time. No major adverse effects were observed.

CONCLUSIONS

A 20-week VLCKD in women with obesity and knee OA significantly reduced their weight and improved their outcomes, warranting further research. This trial is registered with number NCT05848544 on ClinicalTrials.gov.

The influence of pain catastrophizing on pain and function after knee arthroplasty in knee osteoarthritis

Pain catastrophizing is an exaggerated focus on pain sensations. It may be an independent factor influencing pain and functional outcomes of knee arthroplasty. We aimed to evaluate the association between pre-operative pain catastrophizing with pain and function outcomes up to one year after knee arthroplasty. We used data from a cohort study of patients undergoing primary knee arthroplasty (either total or unicompartmental arthroplasty) for knee osteoarthritis. Pain catastrophizing was assessed pre-operatively using the Pain Catastrophizing scale (PCS). Other baseline variables included demographics, body mass index, radiographic severity, anxiety, depression, and knee pain and function assessed using the Western Ontario and McMaster University Index (WOMAC). Patients completed the WOMAC at 6- and 12-months after arthroplasty. WOMAC pain and function scores were converted to interval scale and the association of PCS and changes of WOMAC pain and function were evaluated in generalized linear regression models with adjustment with confounding variables. Of the 1136 patients who underwent arthroplasty (70% female, 84% Chinese, 92% total knee arthroplasty), 1102 and 1089 provided data at 6- and 12-months post-operatively. Mean (± SD) age of patients was 65.9 (± 7.0) years. PCS was associated with a change in WOMAC pain at both 6-months and 12-months (β = - 0.04, 95% confidence interval: - 0.06, - 0.02; P < 0.001) post-operatively after adjustment in multivariable models; as well as change in WOMAC function at 6-months and 12-months. In this large cohort study, pre-operative pain catastrophizing was associated with lower improvements in pain and function at 6-months and 12-months after arthroplasty.

Controlled posterior condylar milling technique for unicompartmental knee arthroplasty minimises tibia resection during gap balancing: Short-term clinical results

PURPOSE

The purpose of this study was to demonstrate the clinical utility of controlled posterior condylar milling (CPCM) in gap balancing while minimally resecting the tibia during fixed-bearing unicompartmental knee arthroplasty (UKA).

METHODS

This study is a retrospective cohort study. Patients who underwent medial UKA for isolated medial compartment osteoarthritis with a minimum follow-up of 2 years were included. The patients were divided into two groups: the conventional group (n = 56) and the CPCM group (n = 66). In the CPCM group, the proximal tibia was resected at the level of the distal end of the subchondral bone. If the flexion gap was tighter than extension, the posterior condyle was additionally milled to adjust gap tightness. Standing knee X-ray and scanogram were used to evaluate alignment and tibia resection amount. Range of motion (ROM) and Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) scores were used to evaluate clinical outcomes.

RESULTS

The CPCM group showed significantly smaller tibia resection (3.6 ± 1.9 mm) compared to the conventional group (5.2 ± 2.7 mm) (p < 0.001). Postoperative ROM (133.0 ± 8.3°, 135.2 ± 7.2°, n.s.) and WOMAC (19.3 ± 13.6, 23.6 ± 17.7, n.s.) were not significantly different between the two groups. Postoperative periprosthetic fractures occurred in two patients in conventional group, while the CPCM group had no periprosthetic fractures.

CONCLUSION

The CPCM technique may be a simple and useful intraoperative technique that can achieve minimal tibia resection and promising clinical outcomes while easily adjusting gap tightness between flexion and extension during medial fixed-bearing UKA.

LEVEL OF EVIDENCE

Level III.