Comparison of KOOS Scores of Middle-Aged Patients Undergoing Total Knee Arthroplasty to the General Dutch Population Using KOOS Percentile Curves: The LOAS Study

Longitudinal Invariance Testing Of The Knee Injury Osteoarthritis Outcome Score For Joint Replacement Scale (KOOS-JR)

Background

The Knee Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) is a seven-item patient reported outcome measure used to assess perceived knee health. Though commonly used, the longitudinal psychometric properties of the KOOS-JR have not been established and further characterization of its structural validity and multi-group invariance properties is warranted.

Purpose

The purpose of this study was to evaluate psychometric properties of the KOOS-JR in a large sample of patients who received care for knee pathology.

Study Design

Original research.

Methods

Longitudinal data extracted from the Surgical Outcome System (SOS) database of 13,470 knee pathology patients who completed the KOOS-JR at baseline, three-months, six- months, and one-year. Scale structure was assessed with confirmatory factor analysis (CFA), while multi-group and longitudinal invariance properties were assessed with CFA-based procedures. Latent group means were compared with statistical significance set at α ≤ .05 and Cohen's d effect size as d = 0.2 (small), d = 0.5 (medium), and d = 0.8 (large).

Results

CFA results exceeded goodness-of-fit indices at all timepoints. Multi-group invariance properties passed test requirements. Longitudinal analysis identified a biased item resulting in removal of item #1; the retained six-item model (KOOS-JR-6) passed longitudinal invariance requirements. KOOS-JR-6 scores significantly changed over time (p ≤ .001, Mdiff = 1.08, Cohen's d = 0.57): the highest scores were at baseline examination and the lowest at 12-month assessment.

Conclusions

The KOOS-JR can be used to assess baseline differences between males and females, middle and older aged adults, and patients receiving total knee arthroplasty or non-operative care. Caution is warranted if the KOOS-JR is used longitudinally due to potential measurement error associated with item #1. The KOOS-JR-6 may be a more viable option to assess change over time; however, more research is warranted.

Level of Evidence

3© The Author(s).

Digital Rehabilitation after Knee Arthroplasty: A Multi-Center Prospective Longitudinal Cohort Study

Rehabilitation for total knee replacement (TKA) often involves in-person therapy sessions, which can be time consuming and costly. Digital rehabilitation has the potential to address these limitations, but most of these systems offer standardized protocols without considering the patient's pain, participation, and speed of recovery. Furthermore, most digital systems lack human support in case of need. The aim of this study was to investigate the engagement, safety, and clinical effectiveness of a personalized and adaptative app-based human-supported digital monitoring and rehabilitation program. In this prospective multi-center longitudinal cohort study, 127 patients were included. Undesired events were managed through a smart alert system. Doctors were triggered when there was a suspicion of problems. The drop-out rate, complications and readmissions, PROMS, and satisfaction were collected through the app. There was only 2% readmission. Doctor actions through the platform potentially avoided 57 consultations (85% of alerts). The adherence to the program was 77%, and 89% of the patients would recommend the use of the program. Personalized human-backed-up digital solutions can help to improve the rehabilitation journey of patients after TKA, lower healthcare-related costs by lowering the complication and readmission rate, and improve patient reported outcomes.

Preoperative Pain Catastrophizing Prior to Total Knee Arthroplasty is Associated With Worse Preoperative Symptoms and More Clinical Improvement: A Prospective Comparative Study

BACKGROUND

Total knee arthroplasty (TKA) is a reliable procedure for end-stage osteoarthritis with excellent long-term survivorship, but approximately 15% of patients are not satisfied. Pain catastrophizing (PC) has been proposed as a potential cause but current evidence is limited to smaller studies with short-term follow-up. Our goal was to assess outcomes following TKA in a large cohort with and without PC.

METHODS

A prospective comparative study was performed with patients undergoing unilateral primary TKA between 2019 and 2021 with 2-year follow-up. All patients completed a PC Scale questionnaire preoperatively and a score of minimum 30 was considered PC. Outcomes consisted of Knee injury and Osteoarthritis Outcome Score-Physical Function Shortform (KOOS-PS), Oxford Knee Score (OKS), numeric rating scale Pain, and aseptic revisions. Ultimately, 301 patients were included (mean age 69 years [range, 30-92 years], with 60.8% women). Forty four patients (14.6%) had PC.

RESULTS

Preoperatively, PC patients had inferior KOOS-PS, inferior OKS, and more pain than non-PC patients (all P < .001). PC patients had more improvement from preoperatively to 6 months postoperatively for KOOS-PS, OKS, and pain (all P < .05) and to 12 months for KOOS-PS and OKS (both P < .005). Similarly, PC patients had more improvement from preoperative to 24 months for OKS (P = .003). At 24 months, however, PC patients reported more pain than non-PC patients. There was no difference in revision rates (P = .192).

CONCLUSION

Patients who had PC reported worse function and pain preoperatively but had more improvement to 6 months and 12 months postoperatively. At 24 months, similar subjective function was noted, although PC patients reported more pain.

Preoperative Factors Affecting Patient-reported Outcome Measures for Total Knee Arthroplasty

Objectives:

The aim of this study was to investigate the preoperative factors affecting health-related quality of life (HRQOL) at 3 and 12 months after total knee arthroplasty (TKA).

Methods:

In total, 156 patients who underwent unilateral TKA for knee osteoarthritis were included in the study. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was used as a measure of HRQOL before surgery and 3 and 12 months post-TKA. The Modified Gait Efficacy Scale (mGES) score, tibiofemoral angle, rest pain, walking pain, knee joint range of motion, knee joint extensor strength, and walking speed were recorded preoperatively. Pearson’s correlation coefficient and the correlation ratio were used to calculate the correlation between KOOS and preoperative factors at 3 and 12 months post-TKA. Multiple regression analysis was performed using the stepwise method with the five postoperative KOOS subscales as dependent variables and the other preoperative factors as independent variables.

Results:

Preoperative mGES scores were significantly correlated with KOOS Activities of Daily Living, Sport/Rec, and QOL subscores at 3 months post-TKA and with all five KOOS subscales at 12 months post-TKA. Multiple regression analysis identified mGES as an influencing factor for all KOOS subscales except Pain at 3 months post-TKA and all KOOS subscales except Symptoms at 12 months post-TKA.

Conclusions:

Preoperative walking self-efficacy influenced HRQOL at 3 and 12 months post-TKA. Psychological factors such as self-efficacy should be considered when predicting postoperative outcomes.