Abstract:

BACKGROUND: Severe muscle fiber atrophy can occur in osteoarthritis patients. However, there are few studies about the classification of muscle fiber atrophy and activities of daily living.
OBJECTIVE: To observe the type of muscle fiber atrophy and its relationship with activities of daily living.
METHODS: Totally 24 female osteoarthritis patients, aged (52.4±16.0) years, were selected, who underwent a vastus lateralis muscle biopsy at the time of total hip or knee replacement. At the time of referral to the rehabilitation center, the Functional Independence Measure (FIM) motor score and habitual physical activity at home were evaluated, and the diameter and atrophy factor for each muscle fiber type were measured on the histopathology preparations of the biopsied muscles.
RESULTS AND CONCLUSION: The patients showed muscle fiber atrophy and small angular fibers, and the atrophy factor was significantly increased in type 1, 2A, and 2B fibers, in that order (P < 0.05). The patterns of the fiber type atrophy, consisting of normal, type 2B atrophy, and type 1 and 2AB atrophy, had a significant relationship with the fiber type atrophy (P  < 0.001). The FIM motor score showed a significant correlation among the three patterns of the fiber type atrophy (P  < 0.05). Type 1+2AB has a best effect on activities of daily living in osteoarthritis patients, and type 2B has a minimal effect.