The impact of hemiparalysis on the expression of osteoarthritis

Objective. Primary generalized osteoarthritis (OA), the most prevalent joint disease, is usually symmetric. Sporadic case reports mention decreased OA manifestations in limbs in which there are neurologic deficits, but no systematic research has been published. The aim of the present study was to examine these observations in a planned and controlled survey in a group of patients with OA. Methods. Seventy-five geriatric patients with a history of stroke and hemiparalysis were studied clinically and radiographically (hand radiographs; graded according to a modified Altman method) for the presence and the degree of OA in the hands. Detailed clinical and radiologic scores were calculated for each hand. Demographic, occupational, and neurologic data were collected. Patients with other joint or neurologic conditions were excluded. A group of 55 elderly patients without stroke were similarly studied (controls). Scores in the paralyzed hand were compared with those in the nonparalyzed hand in the stroke patients and subgroups (by Student's paired t-test and Wilcoxon test). Scores in the dominant hands were compared with those in the nondominant hands in stroke patients and control subjects (by Student's paired t-test and Mann-Whitney test). Correlation between the degree of neurologic damage and OA asymmetry (Pearson's correlation coefficient) was also sought. Results. Paralyzed hands showed significantly fewer OA changes than nonparalyzed hands, both clinically and radiologically. This trend, accentuated in patients with more severe paralysis, disappeared in those with mild residual paresis. Asymmetry of OA was more pronounced in patients with flaccid, compared with spastic, paralysis. The degree of paralysis and loss of muscle strength correlated with the degree of OA asymmetry. Women had significantly higher OA scores than men. In the control group, dominant hands had higher OA scores, but this finding was concealed among hemiparalyzed patients. Lifetime gross occupational load and present grip strength did not correlate with the degree of OA. Conclusion. In elderly patients, hemiparalysis reduces ipsilateral hand expression of OA, while OA is accentuated (or increased) in the dominant hand of patients without paralysis. This first systematic study confirms the findings of previous case reports and lends support to the role of biomechanical factors in the development of OA.