Poor Citation of Prior Evidence in Hip Fracture Trials

BACKGROUND: Failure to cite prior evidence in the medical literature may result in publication redundancy and inefficient use of research funding. We evaluated trials in which internal fixation was compared with arthroplasty for the treatment of hip fractures in order to determine the extent to which these randomized trials cited all relevant previous trials. METHODS: We searched MEDLINE and Embase for all relevant articles on four topics: internal fixation compared with arthroplasty, total hip arthroplasty compared with hemiarthroplasty, sliding hip screws compared with other fixation devices, and surgical delay of hip fracture treatment. We determined the proportion of previous studies that were cited in comparison with the total number of previous studies that were citable (i.e., the citation rate) as well as the proportion of times that a study was cited in comparison with the total number of times that it could have been cited (i.e., the hit rate). A cumulative meta-analysis was performed for the "internal fixation compared with arthroplasty" topic to determine whether compelling evidence favoring one intervention existed at an earlier time. RESULTS: In total, sixty studies were assessed and yielded an overall citation rate of 48%. All "highly cited" studies reported a positive result (favoring arthroplasty), and 60% were published in The Journal of Bone and Joint Surgery (American or British volume). The results of a study and the journal of publication significantly affected the hit rate (p < 0.05). CONCLUSIONS: Our review of studies of hip fracture treatment suggests poor citation of the previous literature. Studies in higher-impact journals with positive results are more likely to be cited in subsequent studies. Therefore, redundancy in publication and unnecessary surgical trials often occur.