Influence of the acetabular cup position on hip load during arthroplasty in hip dysplasia.
Placement of the acetabular cup during total hip arthroplasty is of great importance because usually every deviation from the ideal centre of rotation negatively influences endoprosthesis survival, polyethylene wear and hip load. Here we present hip load change in respect to various acetabular cup positions in female patients who underwent total hip replacement surgery due to hip dysplasia. The calculation suggests that, in the majority of cases, for every millimeter of lateral displacement of the acetabular cup (relative to the ideal centre of rotation) an increase of 0.7% in hip load should be expected and for every millimeter of proximal displacement an increase of 0.1% in hip load should be expected (or decreased if displacement is medial or distal). Also, for every millimeter of neck length increase, 1% decrease is expected and for every millimeter of lateral offset, 0.8% decrease is expected. Altogether, hip load decreases when the cup is placed more medially or distally and when the femoral neck is longer or lateral offset is used.
Bicanic
Goran
G
Department of Orthopaedic Surgery, School of Medicine, University of Zagreb, Clinical Hospital Center Zagreb, Zagreb, Croatia. gbic@mef.hr
Delimar
Domagoj
D
Delimar
Marko
M
Pecina
Marko
M
D000077:Acetabulum / Q000000981:diagnostic imaging / Q000601:surgery*; D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D001696:Biomechanical Phenomena; D015331:Cohort Studies; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging / Q000503:physiopathology; D005500:Follow-Up Studies; D006618:Hip Dislocation, Congenital / Q000150:complications*; D006622:Hip Prosthesis; D006801:Humans; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging / Q000209:etiology* / Q000601:surgery*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology; D020127:Recovery of Function; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013314:Stress, Mechanical; D013499:Surface Properties; D016896:Treatment Outcome; D016474:Weight-Bearing; D055815:Young Adult