COX-2 up-regulation in idiopathic carpal tunnel syndrome

The objective of this study was to determine whether cyclooxygenase-2 (COX-2) is up-regulated in the synovium of patients with carpal tunnel syndrome. Twenty patients were enrolled: 16 consecutive patients with carpal tunnel syndrome and four control patients (exploration for non-carpal tunnel syndrome-related wrist or forearm pathology). Clinical data (demographics, pertinent history, symptomatology) were obtained preoperatively. Flexor tenosynovial tissue was isolated from all patients and clinically graded as thin, intermediate, or thick. Histologic evaluation was conducted to rule out the presence of inflammatory cells. Immunohistochemical staining for COX-2 was performed. The immunohistochemical data were confirmed by reverse transcriptase-polymerase chain reaction analysis of COX-2 mRNA. Results showed that the majority of carpal tunnel syndrome specimens (88 percent) showed synovial hypertrophy compared with 0 percent of the controls (p < 0.05). Also, 69 percent of carpal tunnel syndrome specimens (11 of 16) versus 0 percent of controls (zero of four) stained positively for COX-2 (p < 0.05). Of the carpal tunnel syndrome patients, 91 percent of thick specimens versus 33 percent of intermediate specimens versus 0 percent of thin specimens showed COX-2 staining. The authors conclude that synovial hypertrophy is a prominent finding in carpal tunnel syndrome. COX-2 is up-regulated in the tenosynovium of patients with carpal tunnel syndrome, and this upregulation may correlate with the clinical grade of the tenosynovium. The role of COX-2 in carpal tunnel syndrome may be to mediate remodeling of pathologic tissue. To this end, it may be a potential therapeutic target for specific inhibition.