Effect of head contact on the rim of the cup on the offset loading and torque in hip joint replacement

Head contact on the rim of the cup causes stress concentration and consequently increased wear. The head contact on the rim of the cup may in addition cause an offset load and torque on the cup. The head–rim contact resulting from microseparation or subluxation has been investigated. An analytical model has been developed to calculate the offset loading and resultant torque on the cup as a function of the translational displacement of the head under simplified loading condition of the hip joint at heel strike during a walking cycle. The magnitude of the torque on the cup was found to increase with the increasing translational displacement, larger diameter heads, eccentric cups, and the coefficient of friction of the contact. The effects of cup inclination, cup rim radius, and cup coverage angle on the magnitude of the torque were found to be relatively small with a maximum variation in the torque magnitude being lower than 20%. This study has shown an increased torque due to the head loading on the rim of the cup, and this may contribute to the incidence of cup loosening. Particularly, metal-on-metal hip joints with larger head diameters may produce the highest offset loading torque.

[1]  J Fisher,et al.  Bioengineering reasons for the failure of metal-on-metal hip prostheses: an engineer's perspective. , 2011, The Journal of bone and joint surgery. British volume.

[2]  G. Bergmann,et al.  Hip joint loading during walking and running, measured in two patients. , 1993, Journal of biomechanics.

[3]  D A Dennis,et al.  "In vivo" determination of hip joint separation and the forces generated due to impact loading conditions. , 2001, Journal of biomechanics.

[4]  J Fisher,et al.  Wear and deformation of ceramic-on-polyethylene total hip replacements with joint laxity and swing phase microseparation , 2003, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine.

[5]  John Fisher,et al.  High Cup Angle and Microseparation Increase the Wear of Hip Surface Replacements , 2009, Clinical orthopaedics and related research.

[6]  P B Pynsent,et al.  Metal-on-metal resurfacing of the hip in patients under the age of 55 years with osteoarthritis. , 2004, The Journal of bone and joint surgery. British volume.

[7]  P Roberts,et al.  Comparison of Contact Mechanics between a Total Hip Replacement and a Hip Resurfacing with a Metal-On-Metal Articulation , 2005 .

[8]  J. Fisher,et al.  Long-term wear of ceramic matrix composite materials for hip prostheses under severe swing phase microseparation. , 2003, Journal of biomedical materials research. Part B, Applied biomaterials.

[9]  A S Greenwald,et al.  Alternative Bearing Surfaces: The Good, the Bad, and the Ugly , 2001, The Journal of bone and joint surgery. American volume.

[10]  Zhongmin Jin,et al.  PRESIDENTIAL GUEST LECTURE: Tribology of Alternative Bearings , 2006, Clinical orthopaedics and related research.

[11]  L. Dorr,et al.  Wear and range of motion of different femoral head sizes. , 2010, The Journal of arthroplasty.

[12]  Z. Jin,et al.  The initial stability and contact mechanics of a press-fit resurfacing arthroplasty of the hip. , 2007, The Journal of bone and joint surgery. British volume.

[13]  J Fisher,et al.  Microseparation of the centers of alumina-alumina artificial hip joints during simulator testing produces clinically relevant wear rates and patterns. , 2000, The Journal of arthroplasty.

[14]  John Fisher,et al.  Three-dimensional modeling of in vitro hip kinematics under micro-separation regime for ceramic on ceramic total hip prosthesis: an analysis of vibration and noise. , 2010, Journal of biomechanics.

[15]  Philippa Cann,et al.  Edge loading in metal-on-metal hips: low clearance is a new risk factor , 2012, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine.

[16]  Zhongmin Jin,et al.  Influence of acetabular cup rim design on the contact stress during edge loading in ceramic-on-ceramic hip prostheses. , 2011, The Journal of arthroplasty.

[17]  Susan Morgan,et al.  Comparison of friction and lubrication of different hip prostheses , 2000 .

[18]  Harlan C. Amstutz,et al.  Metal on Metal Surface Replacement of the Hip: Technique, Fixation, and Early Results , 1996, Clinical orthopaedics and related research.

[19]  P Roberts,et al.  Hip resurfacing arthroplasty: The evolution of contemporary designs , 2006, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine.

[20]  J Fisher,et al.  Effect of microseparation on contact mechanics in ceramic-on-ceramic hip joint replacements , 2002, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine.

[21]  D A Dennis,et al.  An in vivo determination of total hip arthroplasty pistoning during activity. , 2000, The Journal of arthroplasty.

[22]  John Fisher,et al.  In vitro investigation of friction under edge‐loading conditions for ceramic‐on‐ceramic total hip prosthesis , 2010, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[23]  T D Brown,et al.  A Finite Element Analysis of Factors Influencing Total Hip Dislocation , 1998, Clinical orthopaedics and related research.

[24]  Mazen Al-Hajjar,et al.  Effect of cup inclination angle during microseparation and rim loading on the wear of BIOLOX® delta ceramic-on-ceramic total hip replacement. , 2010, Journal of biomedical materials research. Part B, Applied biomaterials.

[25]  M A Wimmer,et al.  Investigation on stick phenomena in metal-on-metal hip joints after resting periods , 2006, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine.