Existing published knee rating systems that assess sports participation, knee function, and subjective symptomatology following ligamentous surgical procedures were analyzed. Major errors in questionnaire design and data reduction have led to invalid conclusions. A questionnaire containing a minimum set of rating criteria was formulated to validly assess athletic participation before and after treatment or surgery. Select questions and a data reduction format were established to assess the intensity of sports participation, changes in sports participation, the variables that produced the changes, self-assessed functional limitations, and the ability to participate in different types of sports. A clinical trial of the questionnaire was performed on 59 patients. An interview conducted upon completion of the questionnaire enabled the authors to detect difficulties or inconsistencies in the responses to the questions. The design format described in this report forms the basis for a subjective evaluation of ligamentous surgery. A standard format for analysis of sports participation and knee function is proposed to aid investigators in comparing variations in clinical results.