Patient-specific hip geometry has greater effect on THA wear than femoral head size

• Published in: Journal of biomechanics Vol. 49; no. 16; pp. 3996 - 4001
• Main Authors: Daniel, Matej, Rijavec, Boris, Dolinar, Drago, Pokorný, David, Iglič, Aleš, Kralj-Iglič, Veronika
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 08-12-2016; Elsevier Limited
• Subjects: Acetabulum - anatomy & histology; Acetabulum - physiology; Aged; Angles (geometry); Arthroplasty, Replacement, Hip; Biomedical materials; Contact pressure; Design; Female; Femur Head - anatomy & histology; Femur Head - physiology; Geometry; Hip joint; Hip Prosthesis; Humans; Hypotheses; In vivo methods and tests; Joint surgery; Kinematics; Linear penetration; Male; Mathematical models; Middle Aged; Muscle, Skeletal - anatomy & histology; Muscle, Skeletal - physiology; Musculoskeletal system; Patient-Specific Modeling; Patients; Physical Medicine and Rehabilitation; Polyethylene; Purchasing groups; Studies; Surgical implants; UHMWPE; Wear; Wear rate; Design; Contact pressure; UHMWPE; Linear penetration
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/j.jbiomech.2016.10.030

Abstract In vivo linear penetration in total hip arthroplasty (THA) exhibits similar values for 28 mm and 32 mm femoral head diameter with considerable variations between and within the studies. It indicates factors other than femoral head diameter influence polyethylene wear. This study is intended to test the effect of patient׳s individual geometry of musculoskeletal system, acetabular cup orientation, and radius of femoral head on wear. Variation in patient׳s musculoskeletal geometry and acetabular cup placement is evaluated in two groups of patients implanted with 28 mm and 32 mm THA heads. Linear wear rate estimated by mathematical model is 0.165–0.185 mm/year and 0.157–0.205 mm/year for 28 and 32 mm THA heads, respectively. Simulations show little influence femoral head size has on the estimated annual wear rate. Predicted annual linear wear depends mostly on the abduction angle of the acetabular cup and individual geometry of the musculoskeletal system of the hip, with the latter having the greatest affect on variation in linear wear rate.