title: Influence of clearance on the time-dependent performance of the hip following hemiarthroplasty: a finite element study with biphasic acetabular cartilage properties.
abstract: Hip hemiarthroplasty is a common treatment for femoral neck fracture. However, the acetabular cartilage may degenerate after hemiarthroplasty leading to postoperative failure and the need for revision surgery. The clearance between the acetabular cartilage and head of the prosthesis is one of the potential reasons for this failure. In this study, the influence of joint clearance on the biomechanical function of a generic hip model in hemiarthroplasty was investigated using biphasic numerical simulation. Both a prolonged loading period of 4000 s and dynamic gait load of 10 cycles were considered. It was found that a larger clearance led to a higher stress level, a faster reduction in load supported by the fluid and a faster cartilage consolidation process. Additionally, the mechanical performance of the acetabular cartilage in the natural model was similar to that in the hemiarthroplasty model with no clearance but different from the hemiarthroplasty models with clearances of 0.5mm and larger. The results demonstrated that a larger clearance in hip hemiarthroplasty is more harmful to the acetabular cartilage and prosthesis heads with more available dimensions (i.e. smaller increments in diameter) could be manufactured for surgeons to achieve a lower clearance, and reduced contact stress in hemiarthroplasty surgeries.
authors: Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, UK. Electronic address: ljyjerry@gmail.com.
authors: Junyan
authors: J
authors: Li
authors: Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, UK.
authors: Xijin
authors: X
authors: Hua
authors: Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, UK; School of Mechanical Engineering, Xi'an Jiaotong University, China.
authors: Zhongmin
authors: Z
authors: Jin
authors: Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, UK.
authors: John
authors: J
authors: Fisher
authors: Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, UK.
authors: Ruth K
authors: RK
authors: Wilcox
mesh_terms: D000077:Acetabulum / Q000502:physiology*; D002356:Cartilage / Q000502:physiology*; D020342:Finite Element Analysis; D005684:Gait / Q000502:physiology; D062785:Hemiarthroplasty; D006622:Hip Prosthesis; D011475:Prosthesis Failure; D013997:Time Factors; D016474:Weight-Bearing
keywords: Articular cartilage; Biphasic; Contact mechanics; Finite element; Hemiarthroplasty; Hip