Daltroy 1998.

Methods	Randomised 4‐arm trial using a 2 x 2 factorial design stratified by joint and age (18‐70 years, > 70 years).
Participants	222 participants undergoing total hip replacement (n = 104) or total knee replacement (n = 118) (146 women, 76 men; mean age 64 years, SD 12). Inclusion criteria: participants scheduled for knee or hip replacement. Exclusion criteria: previous hip or knee surgery, inability to speak English or fill out questionnaires. Location: Boston, USA.
Interventions	Information group (n = 58) received a 12‐minute audio‐tape slide programme from a research assistant the day before surgery on the postoperative in‐hospital rehabilitation experience. A pamphlet was also left at the bedside. Relaxation group (n = 58) received training in Benson's Relaxation Response with a bedside audiotape the day before surgery. Information plus relaxation group (n = 52) received the information intervention followed by relaxation training. Control group (n = 54) received neither intervention.
Outcomes	Length of hospital stay; anxiety on day 4 (Spielberger State‐Trait Anxiety Inventory (20‐80 points) higher score represented greater anxiety); pain (1‐5 ordinal scale, where 1 represented least pain and 5 most pain; and charted pain medication used during the first 4 days after surgery); mental status on day 4 (Mini‐Mental State Examination (0‐30 points) higher score represented normal cognition); use of continuous passive motion machine; usefulness of intervention materials.
Notes	Data from the Information plus relaxation group were excluded from the analyses because our inclusion criteria specified that the education/information intervention should be the sole component of the intervention.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "...were assigned randomly to one of the treatment groups." Comment: sequence generation not described.
Allocation concealment (selection bias)	Unclear risk	Comment: allocation concealment not described.
Blinding (performance bias and detection bias) Self‐reported outcomes	High risk	Comment: baseline data were collected before randomisation, so these data are unaffected by group allocation. No description of any attempt to blind patients and blinding is unlikely to have been possible.
Blinding (performance bias and detection bias) Objective outcomes	Low risk	Quote: "In order to conceal the patient's group assignment from nurses, rehabilitation staff, and surgeons, all questionnaires and the intervention itself were administered by either of two research assistants." Comment: staff providing postoperative care were blinded but the research assistants administering the intervention and the outcome questionnaires were not blind. The trial authors reported that staff responses at patient discharge indicated that blinding was successfully implemented among the staff.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "Five patients had incomplete followup questionnaire data and were excluded from all followup analyses except length of stay..." Comment: exclusions pre‐randomisation were described. Post‐randomisation, 1 participant was excluded because of postoperative complications unrelated to the surgery, and 5 had incomplete follow‐up questionnaire data. Neither the reasons for incomplete data nor the distribution between groups were given; however, the impact was likely to be minimal because of the relatively small number of missing participants (less than 3%), plus the outcomes were continuous measures.
Selective reporting (reporting bias)	High risk	Comment: results of all outcomes were partially reported. Trialists only reported means and SDs for both groups combined, and presented mean values of each group, with no measures of variation, in figure format. Trialists also reported that for all outcomes, the differences between groups was not statistically significant. Attempts to retrieve missing data from trialists were unsuccessful. All outcomes listed in the methods were reported in the results, but without the trial protocol, it is unclear whether any other outcomes were measured but not reported based on the results.
Other bias	Low risk	Comment: no other sources of bias identified.