BERLIN — Psychological variables are strongly associated with systems used to measure patient-reported outcomes, thereby reducing the interpretability of these scores following total knee and hip arthroplasty, according to a study presented at the 13th EFORT Congress 2012.
“There are strong correlations between joint-specific outcome measures,” Karlmeinrad Giesinger, MD, MSc, of Kantonsspital St. Gallen, in St. Gallen, Switzerland, said in his presentation. “The scale names suggest that they measure pain, stiffness or function of your joint, but there is a strong association to psychological status. This strong association certainly reduces the interpretability of your joint score.”
For their study, Giesinger and colleagues asked 243 patients to complete four questionnaires after primary, unilateral total knee or hip arthroplasty. These questionnaires included the Forgotten Joint Score, the Brief Symptom Inventory, the Catastrophising-scale and the WOMAC index.
According to Giesinger, variance in the WOMAC score and the Forgotten Joint Score was explained by psychological factors in 54.3% of cases and 30% of cases, respectively. The correlation between a patient’s psychology and the scores was five times stronger than association with implant location, education and gender, according to the study abstract.
Giesinger noted that factors like social support, activity level, cognitive function and range of motion most likely affected the high number of unexplained variances, noting that the cross-sectional design of the study also makes it difficult to establish causal interpretations.
Giesinger K, Behrend H, Giesinger J, Kuster MS. Paper #12-1476. Association of psychological status and patient-reported physical outcome in joint arthroplasty. Presented at the 13th EFORT Congress 2012. May 23-25. Berlin.
Disclosure: Giesinger has no relevant financial disclosures.