Pre-operative pain pressure threshold association with patient satisfaction following Total Knee Arthroplasty

Background: Total knee arthroplasty (TKA) is commonly performed for the treatment of knee osteoarthritis (KOA). Poor satisfaction continues to be seen after TKA. Whilst reasons for poor patient satisfaction are multifactorial, there is a strong correlation with persistent pain following TKA. Studies have shown an association between local and remote mechanical hypersensitivity, measured using pressure pain thresholds (PPTs), and severity of knee osteoarthritis and functional status. We aimed to determine if the pre -operative PPTs were associated with patient satisfaction following TKA. Methods: A prospective longitudinal study of 77 individuals was undertaken. Regression modelling assessed the relationship between Patient Satisfaction using the Knee Society Score (satisfaction subscale) following TKA for KOA, and PPTs recorded pre-operatively locally and remote to the affected knee, while accounting for potentially confounding patient demographic and psychosocial factors. Results: Lower PPTs (indicating increased mechanical hypersensitivity) locally and remote to the operative knee were modestly associated with lower patient satisfaction in the short-term (six weeks) following TKA (beta 0.25-0.28, adjR2 = 0.14-0.15), independent of demographic or psychosocial influences. However, this relationship progressively diminished in the intermediate and long-term post TKA. Conclusion: While pre -operative PPT measures may provide some foresight to patient satisfaction post TKA in the short term, these measures appear to provide little insight to patient satisfaction in the intermediate and longer term.