Total hip arthroplasty versus hemiarthroplasty for displaced femoral neck fractures in the healthy elderly: a meta-analysis and systematic review of randomized trials

After applying the search strings 628 potentially eligible articles were identified, of which 473 were excluded based upon title, and 52 studies were duplicates of these reports. Another 67 manuscripts were excluded after reviewing the abstract. Contact with the author of one abstract revealed that the trial was still actively recruiting patients. In the next phase of the selection procedure 35 full articles were reviewed of which 24 articles did not meet the predefined eligibility criteria. Two studies were published twice [10, 16, 25, 26]. One report was considered the index report, the other article was searched for additional information. Data from both articles were included in this study. One manuscript was a 13-year follow-up [27] of a previously conducted RCT [28]. Data from both reports were included in the analysis. In conclusion, a total of 11 articles about eight studies were included for the present review and meta-analysis which involved a total of 986 patients [13‐17, 25‐29] (Fig. 1).

Tables 1, 2, 3 and 4 summarize the methodological quality, the methodological characteristics, the characteristics of the interventions and the characteristics of individual studies. Two studies had also included a third (internal fixation) arm [17, 27, 28]. These data were not taken into account, as internal fixation was not assessed in the present study. In all studies inclusion and exclusion criteria were clearly defined prior to the study in order to select patients with an ambulatory and cognitive fit pre-fracture status. The quality of the individual parameters ranged from low to very low (Table 1). In three studies, sealed envelopes were used as randomization system [14‐16, 26]; one of which was stated as block randomization [16]. A fully automated computerized allocation system was used in two studies [10, 13]. Other methods used for treatment allocation were by hospital number [29], fixed treatment sequence [28], and according to the order of admission [17]. The outcome assessor was blinded for the allocated treatment in only one study [17]. Patients were not blinded for treatment in any of the studies. Three studies [10, 15, 16, 25, 26] stated an intention to treat analysis, one a per protocol analysis [13] and four studies did not specify the data analysis method [14, 17, 27‐29]. For all eight studies [13‐17, 25‐29] the follow-up period was at least one year (Table 2). All patients in the THA arm were treated with a cemented stem, except in one study [16] where both cemented and uncemented stems were used. For patients treated with hemiarthroplasty in two studies [16, 29] both cemented and uncemented stems were used; in one study [17] cementing of the stem was not specified. In four studies cemented stems were used; in one study uncemented stems were used. In three studies [13, 14, 28] only unipolar heads were used, in three studies [10, 15, 29] only bipolar heads were used, in one study [16] both types of heads were used and one study [17] did not specify the polarity of the head component of the hemiarthroplasty (Table 3).

The exact recruitment period was not specified in three studies [14‐16]. The number of patients per arm ranged from 17 to 137. Three studies [15, 28, 29] used a single-center design; five studies [10, 13, 14, 16, 17] were performed with a multicenter approach (Table 4).