Trials were included irrespective of blinding, number of patients randomized, and language of the publication.
For randomised trials, two reviewers will independently assess the risk of bias, including sequence generation, allocation concealment, blinding, number of patients with missing outcome data, selective outcome reporting and other sources of bias using a modified version of the Cochrane collaboration risk of bias tool.
Methods presentation lacks information about blinding, number of examiners and measurement reliability, CT plane of acetabular version measurement, and adequacy of the AP pelvic view.
The data collected included baseline characteristics (first author or study group's name, publication year, study design, type of blinding, number of patients, mean age, percentage of males, patient diseases, intervention regimes, and the duration of the follow-up period).
The criteria used to check internal validity were the quality of the sampling, the quality of randomisation and experimenter blinding, sufficient number of participants for statistical evidence, and description of confounders and bias.
Appropriate concealment of allocation mechanisms, blinding, and numbers analysed (intention-to-treat principle) were assessed separately because they are highly important in avoiding bias and distortions of the effect estimates [ 4, 9, 26, 31- 35].
Our outcome variable was a 14 point overall reporting quality score (OQRS) and a 3 point key methodological items score (KMIS) based on the proper reporting of allocation concealment, blinding and numbers analysed using the intention-to-treat principle.
All of these studies showed there is poor quality of reporting, with the 3 key methodological items assessed in this study (appropriate allocation concealment mechanism, blinding and numbers analysed by ITT) being highlighted as poorly reported [ 17, 21, 23- 27, 35, 44].
Then an evidence table was constructed for groups of studies concerning one subject, in which following parameters were scored: year of publication, randomization, blinding, set-up, number of patients, duration of treatment, lost to follow-up (number, reason), outcomes, efficacy, safety, and grading of level of evidence.
If un-blinding needed to occur, the study coordinator noted the un-blinded patient's identification number, reason for un-blinding, person responsible for un-blinding study staff, and the list of persons now un-blind to the patient's treatment.
§Randomisation: none (score 0), mentioned (1), described and adequate (that is, computer generated list of random numbers, or sealed envelopes) (2); blinding: none or observer blinding only (score 0), double blinding described but not optimal (1), optimal (double dummy or convincing blinding procedures) (2); drop-outs: not described or incomplete (score 0), clear follow-up of each patient (1).
