Quantitative Evaluation of the Presence of Sarcopenia in Coxarthrosis Using Computed Tomography.

BACKGROUND: Sarcopenia and coxarthrosis frequently coexist in older adults and may contribute to functional decline. Computed tomography (CT)-based muscle measurements are commonly used for the assessment of sarcopenia. AIM: To quantitatively evaluate the relationship between the presence and severity of coxarthrosis and sarcopenia using computed tomography (CT) and to investigate the usability of the upper thigh skeletal muscle as an alternative to the psoas muscle in the evaluation of sarcopenia in coxarthrosis. METHODS: Patients who underwent a hip CT examination between June 2019 and May 2023 were evaluated retrospectively. Patients with coxarthrosis were included in the study. Coxarthrosis staging was performed according to the Tönnis classification. Muscle area and density values were measured at the L4 level for bilateral psoas muscles and skeletal muscle in the upper thigh level at the inferior tip of the ischial tuberosity. RESULTS: Increasing Tönnis grade remained independently associated with lower psoas and upper thigh muscle area and density (all Holm-adjusted P < 0.001). Muscle areas were lower in women than in men ( P = 0.001). There was no significant difference between the genders in terms of the psoas muscle density ( P > 0.05), while the upper thigh muscle density was significantly lower in women than in men ( P < 0.05). A positive correlation was detected between the areas and densities of the psoas and upper thigh muscles in every grade of coxarthrosis. CONCLUSION: The presence and severity of coxarthrosis are associated with the area and density of the psoas and upper thigh skeletal muscles. Upper thigh skeletal muscles may serve as an alternative muscle group for the imaging-based evaluation of sarcopenia.