Background

Superstition is a multifaceted concept that involves an erroneous establishment of cause and effect [1]. It has been suggested that individuals turn to superstitious beliefs as coping mechanisms during challenging times, attempting to make sense of and control uncertainty [2, 3]. While superstition may seem at odds with evidence-based healthcare in today’s scientifically dominated world, there is a consensus that surgeons should be mindful of their patients’ spirituality and belief systems [4]. For instance, despite originating more than 2400 years ago, horoscopes and zodiac signs continue to be a constant feature in our society [5, 6]. Forms of superstition, such as considering Friday the 13th as a day of misfortune, are deeply ingrained in the general population [7, 8].

Conducting well-founded investigations into such phenomena could enhance clinician-patient communication and shared decision-making. Therefore, this study aims to address the following research question: Do surgical outcomes, in terms of complication rates and mortality after total knee arthroplasty (TKA) and total hip arthroplasty (THA), get influenced by Friday the 13th? Additionally, as superstitions might affect surgical planning, we have also examined whether there are differences in the number of surgeries performed on these days.