Reliability of Hallux Rigidus Radiographic Grading System

Introduction. The purpose of this study was to determine the interand intra-observer reliability of a clinical radiographic scale for hallux rigidus. Methods. A total of 80 patients were retrospectively selected from the patient population of two foot and ankle orthopaedic surgeons. Each corresponding series of radiographic images (weightbearing anteroposterior, weight-bearing lateral, and oblique of the foot) was randomized and evaluated. Re-randomization was performed and the corresponding radiograph images renumbered. Four orthopaedic foot and ankle surgeons graded each patient, and each rater reclassified the re-randomized radiographic images three weeks later. Results. Sixty-one out of 80 patients (76%) were included in this study. For intra-observer reliability, most of the raters showed “excellent” agreement except one rater had a “substantial” agreement. For inter-observer reliability, only 14 out of 61 cases (23%) showed total agreement between the eight readings from the four surgeons, and 11 out of the 14 cases (79%) were grade 3 hallux rigidus. One of the raters had a tendency to grade at a higher grade resulting in poorer agreement. If this rater was excluded, the results demonstrated a “substantial” agreement by using this classification. Conclusion. The hallux rigidus radiographic grading system should be used with caution. Although there is an “excellent” level of intra-observer agreement, there is only “moderate” to “substantial” level of inter-observer reliability. KS J Med 2015;8(4):125-134. Introduction Osteoarthrosis of the first metatarsophalangeal (MTP) joint of the foot may cause significant pain, disability, and difficulty wearing footwear. The term, hallux rigidus, is used to describe a condition commonly associated with degenerative arthritis of the first MTP joint with osteophyte formation, which results in a painful joint with reduction in the range of motion, especially dorsiflexion. Hallux rigidus is a progressive condition, and may present in early or late stages with varying degrees of stiffness and osteophytic thickening of the joint. Chronic MTP joint inflammation leads to capsular distention and eventually to a loss of capsular and collateral ligament integrity. Throughout the literature discussing foot and ankle disabilities, there have been multiple classification methods for hallux rigidus that have involved clinical findings, radiographic findings, or a combination of both. The role of these classification systems is to help a physician to choose an appropriate method of treatment as well as to provide a reasonably precise estimation of the outcome of that treatment. Some researchers have used these classification systems to compare the results of different studies and treatment procedures. For these classification systems to be useful, the classification system must produce the same desired results time after time in the hands of any physician or researcher who attempts to use it. Reliable