MUSCLE STRENGTH AND ENDURANCE AFTER SURGERY FOR PRIMARY HYPERPARATHYROIDISM

Objective: To evaluate the effect of surgery on muscular strength and endurance in patients with primary hyperparathyroidism (HPT). Design: prospective open study. Setting: University hospital, Sweden. Subjects : Nine patients undergoing HPT surgery and nine matched patients under going thyroid resection who acted as controls. Interventions: Concentr ic and eccentric endurance was evaluated with a test comprising 100 re peatedly executed muscle actions at 90 degrees . s(-1). Blood samples obtained before and after operation were analysed for calcium, phospha te, thyroid stimulating hormone (TSH), and parathyroid hormone (PTH) c oncentrations. Main outcome measures: Peak torque during maximum volun tary concentric and eccentric muscle actions at 90 degrees . s(-1) bef ore, three months and one year after operation. Results: There were no differences in concentric and eccentric peak torque before and after operation either within or between groups. Concentric and eccentric en durance were similar in the HPT group and controls before as well as a fter operation. The return of calcium and PTH concentrations to their reference ranges after parathyroidectomy did not correlate with change s in concentric and eccentric peak torque. Conclusions: The subjective improvement in muscle endurance which is often encountered in patient s with HPT after operation is not associated with an objective increas e in muscle strength or endurance as measured by isokinetic muscle per formance.