Functional and physiological measures in individuals with hip osteoarthritis
Hip , Osteoarthritis
Background: Osteoarthritis of the hip joint causes difficulties to the elderly because it impacts their ability to conduct their normal activities of daily living, such as walking, cooking, bathing, dressing, using the toilet, and performing household chores. Moreover, the joints can become painful, stiff, and swollen. The resulting pain causes limited motion, restriction of social activities, and compromised work capacity. The interaction of these factors can affect both functional and physiological status. The normal course of action for these subjects is to be referred to an orthopedic surgeon; however, the functional and physiological impact of waiting times for hip replacement consultation or surgery on subject’s function has not been properly assessed with objective outcome measures. Objectives: The purpose of this study was to investigate the differences in objective outcome measures of functional and physiological status between subjects with hip OA who were preoperative candidates for hip surgery and those who were diagnosed with hip OA at the time of referral and time of consultation. Methods: Subjects with hip osteoarthritis were selected based on their position in the continuum of care once they had been referred to a surgeon. These groups were: referral (REF) (n=7), consultation (CON) (n=7) and pre-operatively (PREOP) (n=7). Individuals with hip OA were evaluated using functional (6MWT and TUG) and physiological (hip muscle isokinetic strength - Biodex and VO2peak) outcome measures. Results: The 6 minutes walk test (6MWT), timed up and go (TUG) and VO2peak were significantly different between the three groups (p < 0.001, p = 0.005 and p = 0.001). However, no significant difference was observed in hip flexion and extension muscle strength between groups. Post Hoc analysis revealed that the REF group walked significantly greater distances (p < 0.001) when compared to the PREOP group during the 6MWT. Both REF and CON groups showed significantly shorter times in the TUG test (p < 0.009 and p < 0.02 respectively) when compared to the PREOP group and finally the VO2peak in the REF group was significantly higher than the predicted VO2peak of the CON (p = 0.002) and the PREOP (p = 0.002) groups, respectively. Conclusion: Subjects with hip osteoarthritis who are within four weeks of surgery generally walked shorter distances, demonstrate worse mobility and balance control and a lower aerobic capacity than individuals with hip OA at the time of referral to a surgeon and at the time of consultation with the surgeon. Contrary to expectation, this study did not find differences in hip muscle strength, between those with hip osteoarthritis at the time of referral; at the time of consultation and within four weeks prior to surgery.