Shicheng Zhou1, Seungyun Jung2, Jihyo Hwang3. 1. Department of Orthopaedic Surgery, The 2nd Hospital of Jilin University, Ziqiang, China. 2. Department of Orthopaedic Surgery, Gangnam Sacred Heart Hospital, Hallym University School of Medicine, Seoul, Republic of Korea. 3. Department of Orthopaedic Surgery, Gangnam Sacred Heart Hospital, Hallym University School of Medicine, Seoul, Republic of Korea. Electronic address: hwangjihyo73@hallym.or.kr.
Abstract
BACKGROUND: A stress-riser fracture develops when stress in an object is higher than that in the surrounding material. The aim of this retrospective study was to evaluate all consecutive femoral stress-riser fractures during a period of >10 years and to verify high-risk factors by using mechanical analysis. METHODS: Forty clinical fractures caused by local stress concentration in the femoral cortical bone were included. Risk factors were analyzed, and Sawbones models were used to verify their effect. One hundred thirty-six models were divided into 6 groups to simulate clinical cases of stress-riser fractures. A dynamic test instrument was used to simulate weight-bearing on the femoral head by continuous application of increasing axial force; the lever arm was applied at a constant speed of 0.1 mm/s until a fracture developed. RESULTS: Female gender (57.5%), subtrochanteric area (40%), osteoporosis (40%), and technical or surgical errors (50%) were risk factors for stress-riser fractures in clinical analysis. Cortical perforation, tiny cracks, sharp corners, and changes in hardness were the main risk factors in biomechanical aspects. Mechanical analysis identified that these factors contributed to stress-riser fractures (P = 0.000), especially cortical perforations and sharp corners. CONCLUSION: A cortical perforation (screw hole), tiny crack (fracture line), sharp corner (bone cut), and change in hardness (tip of an implant or cement) can act as a stress riser. Screw holes are the most common and critical contributor to femoral stress-riser fractures.
BACKGROUND: A stress-riser fracture develops when stress in an object is higher than that in the surrounding material. The aim of this retrospective study was to evaluate all consecutive femoral stress-riser fractures during a period of >10 years and to verify high-risk factors by using mechanical analysis. METHODS: Forty clinical fractures caused by local stress concentration in the femoral cortical bone were included. Risk factors were analyzed, and Sawbones models were used to verify their effect. One hundred thirty-six models were divided into 6 groups to simulate clinical cases of stress-riser fractures. A dynamic test instrument was used to simulate weight-bearing on the femoral head by continuous application of increasing axial force; the lever arm was applied at a constant speed of 0.1 mm/s until a fracture developed. RESULTS: Female gender (57.5%), subtrochanteric area (40%), osteoporosis (40%), and technical or surgical errors (50%) were risk factors for stress-riser fractures in clinical analysis. Cortical perforation, tiny cracks, sharp corners, and changes in hardness were the main risk factors in biomechanical aspects. Mechanical analysis identified that these factors contributed to stress-riser fractures (P = 0.000), especially cortical perforations and sharp corners. CONCLUSION: A cortical perforation (screw hole), tiny crack (fracture line), sharp corner (bone cut), and change in hardness (tip of an implant or cement) can act as a stress riser. Screw holes are the most common and critical contributor to femoral stress-riser fractures.
Authors: Megan R Hsu; Henry T Shu; Kitchai Luksameearunothai; Adam Margalit; Andrew T Yu; Erik A Hasenboehler; Babar Shafiq Journal: J Orthop Date: 2022-02-16
Authors: Jason S Hoellwarth; Kevin Tetsworth; John Kendrew; Norbert Venantius Kang; Oscar van Waes; Qutaiba Al-Maawi; Claudia Roberts; Munjed Al Muderis Journal: Bone Joint J Date: 2020-02 Impact factor: 5.082