{'fraction_non_alphanumeric': 0.01791044776119403, 'fraction_numerical': 0.0007462686567164179, 'mean_word_length': 5.447115384615385, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Evolution of bearing surfaces in total hip arthroplasty: a review

The longevity of an artificial joint has always been a concern for orthopaedic surgeons and has recently become increasingly important given the changing demographics of total joint patients. The increase in life expectancy and the shift to younger patients undergoing total joint arthroplasty demand higher levels of activity and greater expectations from the new joints. Wear and the resulting osteolysis have been identified as major causes for implant failure. Both modes of failure are affected by a number of interrelated factors, of which bearing surface tribology (lubrication, friction and wear) is one of the most important. During the past 4 decades, bearing surfaces have gone through a significant evolution, starting with Charnley's own experience that led to the low-friction arthroplasty to the present day's third generation ceramic-on-ceramic bearing surfaces and sequentially cross-linked polyethylene. A careful review of this evolutionary process is critical to a better understanding of the development of all available options, along with their strengths and weaknesses. Additionally, it may help to identify future questions to guide the research in this field, with the ultimate goal of improving outcomes and better meeting patients' expectations.