Recent evidence suggests that patient factors can influence response to medical and surgical treatment and may play an under-recognized role in predicting treatment outcomes. However, the current state of knowledge concerning potential associations following orthopedic surgery in particular is unclear. The purpose of the present study was to systematically review current literature to investigate the currently known associations between pre-operative patient factors and patient-reported outcomes following orthopedic surgery.
A systematic review was performed of the PubMed database to identify original studies that investigated the relationships between one or more patient factors and patient-reported outcomes of primary orthopedic surgical procedures involving implantation of a medical device. A total of 10,174 records were identified, with 83 studies included in the final review.
The most commonly assessed patient factors included age, sex, and body mass index (BMI), reported in 63%, 55%, and 48% of studies, respectively. The only other patient factors identified were socioeconomic status and race, both of which were assessed in a single study. Considerable heterogeneity was observed in the methods used to stratify subjects by patient factors, patient-reported outcome constructs assessed, and follow-up intervals. Only 10% of studies performed appropriate sample size or power calculations, only 51% used methodologies to control for potentially confounding factors, and 6% assessed responder status. Overall, variable and conflicting findings were seen. While female sex and increasing BMI did appear to be associated with worse absolute outcomes, these differences did not appear to be maintained when differences in baseline status were considered. No clear associations between age and outcomes were identified.
The present understanding of these relationships between patient factors and patient-reported outcomes following orthopedic surgery is limited. There is a need for further studies using high-quality methodology, consistent stratification of participants based on patient factors, accepted patient-reported outcome constructs, and appropriate assessment of responder status.