Randomized, controlled trials (RCTs) are generally accepted as the “gold standard” for the provision of the most unbiased measures of the efficacy of interventions but are often criticized for the lack of external validity. We assessed the external validity of a RCT examining the efficacy of local infiltration analgesia (LIA) compared with continuous epidural infusion after total knee arthroplasty (TKA) During a one-year period, all patients consecutively admitted for elective, unilateral, primary TKA were identified as potential participants. All underwent eligibility screening to determine who were eligible for participation in a randomized controlled trial. We investigated the distribution of preoperative characteristics and postoperative variables among excluded patients, non-consenters, and enrolled and randomized participants.Background
Methods
At follow-up weight-bearing AP pelvis radiographs were obtained. OA was present when the minimum joint space width was <
2.0 mm. Radiographs of sex- and age-matched controls were obtained from The Copenhagen City Heart Study. The following criteria for exclusion were applied:
insufficient or missing radiographs patients who refused to participate, emigrated persons, persons lost to follow-up, patients with previous surgery to pelvis or lower limbs and dead persons. 52 patients (55 hips) were enrolled in the study and 115 patients (136 hips) were excluded. Mean age for men at follow-up was 53 years and for women 55 years.
Radiographs of sex- and age-matched controls for the follow-up group were obtained from The Copenhagen City Heart Study. The following criteria for exclusion were applied
emigrated persons, persons lost to follow-up and patients with previous surgery to pelvis or lower limbs. 135 patients (156 hips) were enrolled in this study and 32 patients (35 hips) were excluded.
