Stair Climbing Ability and Identification of the Nine Stairs Ascent and Descent Test Cut-Off Points in Hip Osteoarthritis Patients: A Retrospective Study

Objectives As the prevalence and incidence of hip osteoarthritis (hip OA) continue to rise, measuring the impact of hip OA severity on a patient's functionality is essential. Stair walking is a particularly relevant task to assess hip OA patients, as difficulty with stair ascent is one of the driving factors in deciding to undergo a total hip arthroplasty. Although stairs tests often arise in post-arthroplasty measures, there is a lack of reported stairs performance time in hip OA patients. Therefore, this retrospective study aimed to report the stair performance time of hip OA patients categorized by disease severity and determine cut-off points that differentiate between severity grades. Materials and methods The patient selection was based on the review of de-identified data from our research laboratory database. 254 hip OA patients (aged ≥ 50 years) were divided according to the Kellgren-Lawrence classification system into three groups: Grade 2 (n=68), Grade 3 (n=109), and Grade 4 (n= 68). The stair-walking ability was evaluated using the 9S-A/D test. The time taken to ascend and descend the stairs was measured separately, and the total time (9S-A/D) was also recorded. The one-way ANOVA model, Welch test, Games-Howell posthoc test, Chi-Square tests, and Two-Way ANOVA model were used for the statistical analysis of the data. The cut-off points were obtained by receiver operating curve (ROC) analysis. The statistical significance was set at p