Prerandomization: an alternative to classic randomization. The effects on recruitment in a controlled trial of arthroscopy for osteoarthrosis of the knee

Abstract

Possibly the greatest threat to the success of a randomized clinical trial is the inability to recruit an adequate number of subjects. Concern that the randomized clinical trial will adversely affect the physician-patient relationship is the most common reason for physicians' reluctance to enroll patients in such trials. We report a modification of a prerandomized design, first described by Zelen, which was implemented in a randomized clinical trial of arthroscopy for patients who had osteoarthrosis of the knee. The method was associated with a sixfold increase in the rate of accrual of patients as compared with the use of a classic randomization trial. We propose the design as a potential solution to the problem of recruitment of subjects, particularly for clinical studies.