This proposal is concerned with adaptive bone remodeling of the femur following cementless and cemented total hip arthroplasty. Clinically, over 50% of the periprosthetic bone mass can be lost following hip arthroplasty. The practical health-related goal is to prolong implant survivorship and facilitate potential revision surgery by minimizing bone loss attributed to stress-shielding, the initial reduction in mechanical loading of the bone in the proximal femur due to load transfer through the prosthesis. The central hypothesis is that (in the absence of osteolysis related to degradation of the implant) stress-shielding represents the most important independent variable or """"""""final common pathway"""""""" through which patient, implant and technical factors account for a large proportion of the bone loss following total hip arthroplasty. If this thesis is correct, then factors such as age and source of implant bonding (e.g., bone ingrowth versus cement fixation) play a role in the adaptive process, largely through mechanically-mediated pathways. The applicants propose to test their hypothesis by examining three of its implications: (i) individual variation in stress-shielding explains a large proportion of the individual variation in femoral bone loss following hip replacement; (ii) bone loss has the same relationship to stress-shielding in skeletally mature young and old animals following cementless hip replacement, even though the actual amount of bone loss may vary as a function of age; and (iii) bone loss has the same relationship to stress-shielding in cemented and cementless total hip arthroplasty. Individual estimates of stress-shielding will be made based on animal-specific finite element modeling of a canine model. These estimates will be correlated with measurements of change in periprosthetic bone mass made in the same animals. In this way, the actual variance in the dependent variable (change in bone mass), explained by variance in the independent variable (stress-shielding) and the nature of the relationship (linear or nonlinear), will be determined. Use of an animal model allows other causes of bone loss to be largely eliminated, thus permitting the effects of stress-shielding to be clearly defined.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
2R01AR016485-23A1
Application #
2647363
Study Section
Special Emphasis Panel (ZRG4-ORTH (05))
Project Start
1979-05-01
Project End
2001-08-31
Budget Start
1997-09-12
Budget End
1998-08-31
Support Year
23
Fiscal Year
1997
Total Cost
Indirect Cost
Name
Rush University Medical Center
Department
Type
DUNS #
City
Chicago
State
IL
Country
United States
Zip Code
60612
Minihane, Keith P; Turner, Thomas M; Urban, Robert M et al. (2005) Effect of hip hemiarthroplasty on articular cartilage and bone in a canine model. Clin Orthop Relat Res :157-63
Qureshi, Abid A; Virdi, Amarjit S; Didonna, Michael L et al. (2002) Implant design affects markers of bone resorption and formation in total hip replacement. J Bone Miner Res 17:800-7
Onsten, I; Berzins, A; Shott, S et al. (2001) Accuracy and precision of radiostereometric analysis in the measurement of THR femoral component translations: human and canine in vitro models. J Orthop Res 19:1162-7
Weinans, H; Sumner, D R; Igloria, R et al. (2000) Sensitivity of periprosthetic stress-shielding to load and the bone density-modulus relationship in subject-specific finite element models. J Biomech 33:809-17
Sumner, D R; Turner, T M; Igloria, R et al. (1998) Functional adaptation and ingrowth of bone vary as a function of hip implant stiffness. J Biomech 31:909-17
Turner, T M; Sumner, D R; Urban, R M et al. (1997) Maintenance of proximal cortical bone with use of a less stiff femoral component in hemiarthroplasty of the hip without cement. An investigation in a canine model at six months and two years. J Bone Joint Surg Am 79:1381-90
Weinans, H; Sumner, D R (1997) Finite Element analyses to study periprosthetic bone adaptation. Stud Health Technol Inform 40:3-16
Smith, A M; Turner, T M; Sumner, D R (1996) Unilateral hip replacement causes bilateral changes in tibial bone mineral content in a canine model. J Bone Miner Res 11:693-6
Bryan, J M; Sumner, D R; Hurwitz, D E et al. (1996) Altered load history affects periprosthetic bone loss following cementless total hip arthroplasty. J Orthop Res 14:762-8
Sumner, D R; Turner, T M; Purchio, A F et al. (1995) Enhancement of bone ingrowth by transforming growth factor-beta. J Bone Joint Surg Am 77:1135-47

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