Total joint
arthroplasty is very effective for improving the quality of life of patients with end-stage
arthritis. Despite advances in materials, surgical technique, and rehabilitation regimens,
joint replacements are still fraught with complications leading to their premature failure. Aseptic loosening and
osteolysis are the primary causes of implant failure. Other reasons include early migration of components leading to instability, lack of ingrowth into implant porosities, and bone loss caused by stress shielding.
Pharmaceutical agents used for preventing and managing
postmenopausal osteoporosis (eg,
bisphosphonates) may in the future play an important role in improving the long-term duration of joint
arthroplasties. Early findings indicate that
bisphosphonates upregulate bone morphogenetic protein-2 production and stimulate new bone formation. Because of their
anabolic effect on osteoblasts,
bisphosphonates have the potential to enhance bone ingrowth into implant porosities, prevent
bone resorption under adverse conditions, and dramatically extend the long-term durability of joint
arthroplasties. The long-term effects of
bisphosphonate use on the mechanical properties of bone have not been adequately investigated. Along with improvements in implant design and material properties,
bisphosphonates and other
pharmaceutical agents may, in the near future, be part of the growing armamentarium that provides more durable joint
arthroplasties.