Jiantao Li1, Menglin Wang2, Jianfeng Zhou3, Hao Zhang4, Lianting Li5. 1. Department of Orthopaedics, Chinese PLA General Hospital, No. 28 Fuxing Road, Beijing 100853, PR China. 2. Department of Otolaryngology Head and Neck Surgery, Peking University Third Hospital, Beijing, 100191, PR China. 3. Department of Emergency, Chinese PLA General Hospital, No. 28 Fuxing Road, Beijing 100853, PR China. 4. Department of Orthopaedics, Chinese PLA General Hospital, No. 28 Fuxing Road, Beijing 100853, PR China. Electronic address: 81954819@qq.com. 5. Department of Orthopaedics, The Third People's Hospital of Qingdao, No. 29 Yongping Road, Qingdao 266041, PR China. Electronic address: liliantingqd31@163.com.
Abstract
OBJECTIVES: In the present study, we evaluated the mechanical outcome of different configurations formed by partially threaded screws (PTS) alone or combined screws consisting of PTS and fully threaded screws (FTS) in the treatment of unstable femoral neck fracture. METHODS: The Pauwels type III unstable femoral fracture and screw models of PTS and FTS were created in 3-matic software and UG-NX software respectively. We assembled the different screw fixation types to the fracture model separately to form the fixation models. We used Abaqus software to perform the finite element analysis. RESULTS: Our results indicated that the peak von Mises stresses of screws increased when some PTSs changed into FTSs in all groups except for the inferior triangle group. FTS in each group underwent the most stress while PTS underwent a little bit of stress. The combined screws fixation types were less likely to be cut-out and was more stable than PTPs alone fixation strategy. Less yielding regions around the screw tunnels for the superior and inferior triangle configuration fixed by combined screws was indicated. Superior triangle fixation model underwent the largest area of stress concentration around the screw holes after screws removal. CONCLUSIONS: For unstable femoral neck fractures, superior results were obtained by stabilizing the fracture with superior or inferior triangle configuration consisting of one PTS and two FTSs. If screws removal was taken into account after fracture union, fixation type of inferior triangle configuration should be the recommended choice.
OBJECTIVES: In the present study, we evaluated the mechanical outcome of different configurations formed by partially threaded screws (PTS) alone or combined screws consisting of PTS and fully threaded screws (FTS) in the treatment of unstable femoral neck fracture. METHODS: The Pauwels type III unstable femoral fracture and screw models of PTS and FTS were created in 3-matic software and UG-NX software respectively. We assembled the different screw fixation types to the fracture model separately to form the fixation models. We used Abaqus software to perform the finite element analysis. RESULTS: Our results indicated that the peak von Mises stresses of screws increased when some PTSs changed into FTSs in all groups except for the inferior triangle group. FTS in each group underwent the most stress while PTS underwent a little bit of stress. The combined screws fixation types were less likely to be cut-out and was more stable than PTPs alone fixation strategy. Less yielding regions around the screw tunnels for the superior and inferior triangle configuration fixed by combined screws was indicated. Superior triangle fixation model underwent the largest area of stress concentration around the screw holes after screws removal. CONCLUSIONS: For unstable femoral neck fractures, superior results were obtained by stabilizing the fracture with superior or inferior triangle configuration consisting of one PTS and two FTSs. If screws removal was taken into account after fracture union, fixation type of inferior triangle configuration should be the recommended choice.