USE OF AN OBJECTIVE-MEASURE OF ARTICULAR STIFFNESS TO RECORD CHANGES IN FINGER JOINTS AFTER INTRAARTICULAR INJECTION OF CORTICOSTEROID

Objective-(1) To measure objectively the subjective improvement in joi nt stiffness following intra-articular injections of corticosteroids, and (2) to record changes in joint stiffness in the first 24 hours aft er injection to look for changes in the physical properties of the joi nt that would be consistent with a crystal synovitis. Methods-The stud y population consisted of 15 patients having 17 metacarpophalangeal jo ints injected as part of their routine care. Measurements were taken b efore injection, at 24 hours, and after one week. Outcome variables in cluded articular stiffness, strength, joint range of movement, and sub jective scores. Results-At 24 hours, mean values for stiffness had inc reased (mean slope from 0.0085 to 0.0123 Nm degree(-1); curve area fro m 0.1003 to 0.1555 units), but the increase was not significant. After one week a significant decrease in ''elastic stiffness'' had occurred (mean slope fi om 0.0085 to 0.0065 Nm degree(-1); P = 0.025). Signifi cant changes in grip, range of movement, and subjective scores were al so found after one week (maximum grip fi om 75.3 to 85.9 N; flexion/ex tension range from 87.0 to 102.4 degrees; pain visual analogue scale ( VAS) from 50 mm to 12 mm; stiffness VAS from 65 mm to 27 mm>. Conclusi ons-An early increase in joint stiffness in some patients following in tra-articular corticosteroids is consistent with a transient synovitis . Symptoms of joint stiffness generally correlate with mechanical meas ures which provide a useful objective index of acute changes in joint pathophysiology.