COPYRIGHT © 2003 BY THE JOURNAL OF BONE AND JOINT SURGERY, INCORPORATED Editorial Introducing Levels of Evidence to The Journal

Orthopaedic surgeons have always based their clinical care on evidence. Surgeons use evidence to make decisions tailored to an individual patient’s needs and circumstances. The primary sources of evidence for clinicians are studies published in the medical and surgical literature, such as The Jour-nal of Bone and Joint Surgery. In June 2000, The Journal introduced the quarterly Evidence-Based Orthopaedics section1. This section introduces orthopaedic surgeons to recent randomized trials relevant to the practice of orthopaedic surgery published in forty-two journals other than The Journal of Bone and Joint Sur-gery. Structured abstracts of these studies are published along with solicited commentaries to place the evidence into context. Beginning this month, The Journal is making an addition to its clinical articles. All such articles will include a Level-of-Evidence Rating. Levels of evidence are hierarchical rating systems for classifying study quality. Several systems for rating levels of evidence are available (minerva.minervation.com/cebm/docs/levels.html). The one chosen by The Journal has five levels for each of four different study typesi.e., therapeutic, prognostic, diagnostic, and economic or decision modeling. The Journal is accordingly modifying its Instructions to Authors: authors sub