Pathological assessment of periprosthetic tissues is important, not only for diagnosis, but also for understanding the pathobiology of implant failure. The host response to wear particle deposition in periprosthetic tissues is characterised by cell and tissue injury, and a reparative and inflammatory response in which there is an innate and adaptive immune response to the material components of implant wear. Physical and chemical characteristics of implant wear influence the nature of the response in periprosthetic tissues and account for the development of particular complications that lead to implant failure, such as osteolysis which leads to aseptic loosening, and soft-tissue necrosis/inflammation, which can result in pseudotumour formation. The innate response involves phagocytosis of implant-derived wear particles by macrophages; this is determined by pattern recognition receptors and results in expression of cytokines, chemokines and growth factors promoting inflammation and osteoclastogenesis; phagocytosed particles can also be cytotoxic and cause cell and tissue necrosis. The adaptive immune response to wear debris is characterised by the presence of lymphoid cells and most likely occurs as a result of a cell-mediated hypersensitivity reaction to cell and tissue components altered by interaction with the material components of particulate wear, particularly metal ions released from cobalt-chrome wear particles. Cite this article: Professor N. A. Athanasou. The pathobiology and pathology of aseptic implant failure.
The patient with a painful arthritic knee awaiting
total knee arthroplasty (TKA) requires a multidisciplinary approach.
Optimal control of acute post-operative pain and the prevention
of chronic persistent pain remains a challenge. The aim of this
paper is to evaluate whether stratification of patients can help
identify those who are at particular risk for severe acute or chronic
pain. Intense acute post-operative pain, which is itself a risk factor
for chronic pain, is more common in younger, obese female patients
and those suffering from central pain sensitisation. Pre-operative
pain, in the knee or elsewhere in the body, predisposes to central
sensitisation. Pain due to osteoarthritis of the knee may also trigger
neuropathic pain and may be associated with chronic medication like
opioids, leading to a state of nociceptive sensitisation called
‘opioid-induced hyperalgesia’. Finally, genetic and personality
related risk factors may also put patients at a higher risk for
the development of chronic pain. Those identified as at risk for chronic pain would benefit from
specific peri-operative management including reduction in opioid
intake pre-operatively, the peri-operative use of antihyperalgesic
drugs such as ketamine and gabapentinoids, and a close post-operative
follow-up in a dedicated chronic pain clinic. Cite this article:
