Evaluation of Tobacco heating system (THS) during closed lower limb fracture healing in trauma smokers’ patients

Abstract

Background Since 1976, it's been recognized that increased cigarette consumption correlates with decreased bone density, hindering fracture healing and leading to prolonged hospitalization. Although prior research has shown the relatively less harmful effects of electronic nicotine delivery systems (ENDS) on bone cells in lab settings and animal models, clinical evidence regarding their impact on fracture healing remains scarce. This study aims to investigate whether switching to a tobacco heating system (THS) post-orthopedic surgery improves outcomes for smoking patients during tibia or femur fracture healing over a 6-month period. Methods The study is a prospective, open-label, non-parallel, single-center trial involving 150 patients from a Level 1 Trauma center, Germany, diagnosed and treated for closed tibia, closed femur shaft, or closed distal femur fractures (according to AO/OTA: 41A2-41C3, 42A-C, 43A-C, 32A-C, 33A2-3, 33B-C). Participants will be categorized into three groups based on smoking behavior: smokers (no intervention), THS (participants switching from cigarettes to THS), and ex-smokers (participants abstaining from cigarettes or ENDS during the study). Clinical, radiological, and laboratory data will be collected during preoperative and postoperative assessments at 6, 12, 18, and 24 weeks. The primary outcome will be the serum concentration of N-terminal propeptide procollagen type 1, a bone formation marker. Secondary outcomes include bone metabolism, healing, immunological, blood count, and clinical parameters. Approval for the study protocol and consent declarations was obtained from the ethics committee of the medical faculty of Eberhard Karls University (724/2022BO1). Discussion The study results will provide evidence that switching to THS previous orthopedic intervention improves clinical outcomes during closed tibia or femur fracture healing in smokers’ patients due to reduced bone resorption rate consequent to the diminished activity of cigarette smoke-activated osteoclast. Trial registration: The study is registered on ClinicalTrials.gov (NCT05859451).