Hill's Matrix Augments the Barell Matrix for Identifying Knee Injuries in Active Duty U.S. Army

• Activity Number: 189
• Type: Invited
• Date/Time: Monday, August 2, 2010 : 10:30 AM to 12:20 PM
• Sponsor: Section on Statistics in Epidemiology
• Author(s): Craig James McKinnon*+ and Owen Hill and Ashley Kay and Monika Wahi
• Companies: United States Army Research Institute of Environmental Medicine and United States Army Research Institute of Environmental Medicine and United States Army Research Institute of Environmental Medicine and United States Army Research Institute of Environmental Medicine
• Keywords: Knee Injury ; Army Personnel ; Wounds and Injuries Classification

Abstract

The Barell Matrix (BM) is an ICD-9-CM injury classification system used in epidemiology. The BM does not classify all knee injuries (KI) commonly presenting among Active Duty US Army (ADA) Soldiers. To address this gap, we propose the Hill Matrix (HM) for identifying KI among ADA. ICD-9-CM diagnoses (first 4 positions) from two random months per year (2000-2007) were extracted from inpatient and outpatient clinical encounter (CE) records for ADA (n=7,792,914). Each CE was classified as identifying KI by BM, HM, or both; discordance was analyzed.HM and BM identified significantly different groups of CEs (McNemar's p < 0.0001). For certain KI (contusions, crushes, dislocations and tears), HM includes all of the BM ICD-9-CM codes. HM includes more codes than BM to identify strains/sprains and fractures; only BM includes burns. Amputations, derangement, and bursitis are only identified in HM.