The Rules of Four: A Systematic Approach to Diagnosing Common Musculoskeletal Conditions of the Knee.

Musculoskeletal symptoms are consistently one of the most commonly cited reasons for visits to ambulatory care centers every year, with knee pain accounting for approximately one-third of the reported complaints. Previous studies have demonstrated that many non-orthopedic physicians report a lack of confidence in performing clinical musculoskeletal knee examinations. "The Rules of Four" approach presented in this paper is designed to present a systematic and concise method to musculoskeletal examination of the knee within a memorable format.