Do anthropometric measures and pain influence functional test performance in knee osteoarthritis

Background & Aims

Various factors including age, weight, height, and pain have been demonstrated to influence functional test performance across different populations. However, their influence specifically within the knee osteoarthritis (KOA) population remains relatively unexplored. While previous research has investigated the predictive value of these factors, particularly in the stair climb test (SCT) post-total knee arthroplasty, their impact on functional tests among patients seeking conservative treatment warrants investigation. This study aims to evaluate the influence of anthropometric measures and pain intensity on the performance of functional tests in individuals with knee osteoarthritis.

Methods

This is an observational, cross-sectional study. Male and female participants with a clinical diagnosis of KOA and pain intensity > 4 (Numeric Rating Scale (NRS)) were recruited. Anthropometric data were collected during anamnesis, followed by the application of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire. Subsequently, participants were asked about their pain (NRS) and then submitted to the 30-second chair stand test (30-s CST), the 4-by-10 m fast-paced walk test (40 m FPWT), and the SCT. Regression analysis was used to determine the influence of clinical and demographic data on the performance of these functional tests. Three ordinal regression models were used, one for each functional test. Models were fitted by maximum likelihood, and predictor effects were evaluated through likelihood ratio tests. Analyses were performed in R language (R version 4.3.2), and the significance level adopted was 5%.

Results

There were 142 participants total, with a mean age of 59 years and 50% of them being female. The participants’ mean body mass index (bmi) was 29.1, their mean NRS pain intensity was 3.5, and their mean WOMAC total score was 47. The 30-s CST was 9, the 40-m FPWT mean was 28.82 seconds, and the SCT was 22.82 seconds. Age (p<0.001), bmi (p = 0.001), and WOMAC (p = 0.005) were found to have a negative association with performance on the FPWT. A negative association of test performance with age (p = 0.015) and WOMAC (p<0.001) was also observed for the 30-s CST. Age (p<0.001), WOMAC (p<0.001), bmi (p<0.001), and NRS (p=0.015) were also negatively associated with performance on the SCT. Furthermore, women performed worse than men on all functional tests (p<0.001).

Conclusions

Advanced age, being female, high BMI, high pretest pain intensity, and low self-reported function were all found to negatively impact functional test performance.

References

Lee, S. J., et al (2020). Preoperative physical factors that predict stair-climbing ability at one month after total knee arthroplasty; Wollesen, B., et al (2017). Influence of age, gender and test conditions on the reproducibility of Dual-Task walking performance. Altman, R., et al (1986)., Development of criteria for the classification and reporting of osteoarthritis. Classification of osteoarthritis of the knee. R Core Team (2023). R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria. https://www.R-project.org/.

Presenting Author

Luiz Fernando Approbato Selistre

Poster Authors

Luiz Fernando Approbato Selistre

PhD

Department of Physiotherapy , Federal University of São Carlos, São Paulo, Brazil

Lead Author

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