Chronic Postsurgical Pain, Postoperative Cognitive Dysfunction and Resilience

"Brain damage" and "memory loss" are main concerns of people undergoing surgery. In fact, many older people undergoing different types of non-cardiac surgeries (including orthopedic surgeries) present a significant decline in their cognition (i.e. the way people use their brain to think, take action, make decision, and remember) 1 year after surgery. This is called postoperative cognitive dysfunction (POCD), and is significantly more frequent (as many as 30% of patients aged 65 or older) than what we would expect in non-surgical patients with similar age and comorbidities. Causes and mechanisms of POCD are poorly understood. Pain after surgery is also very frequent and can persist for a long time (i.e. persistent postsurgical pain, PPSP), requiring chronic medications including narcotics. Knee surgery is more often offered as a treatment in older patients with osteoarthritis, who often come to surgery after a long history of pain and impaired mobility, and who often experience PPSP. The investigators proposed to conduct a study in 200 people 55 years old or older (expected age range 55-85) who are undergoing their elective knee surgery, to evaluate the association between PPSP (and its treatment) and POCD. How cognition can interfere with resilience (coping strategies and expectations), which are also thought to influence the persistence of pain, satisfaction, and functional recovery after surgery, will also be explored. Patients will be enrolled before their surgery and followed over time, to collect data on their social and clinical characteristics, measure copying/expectations before and after surgery, and assess pain and pain medications, satisfaction and functional recovery, and cognitive performance. The study will also explore hypotheses of possible mechanisms underlying the association between PPSP and POCD, and will include interviews with a subset of the participants to explore lived experiences of pain, mobility and aging, including resilience, expectations and satisfaction with surgery.

The specific study objectives are to: 1- explore the association of CPSP, pain management (opioid use), and patient satisfaction, with postoperative cognitive dysfunction (POCD), measured both as change in the Montreal Cognitive Assessment (MoCA), and through a neuropsychological test battery, 2- explore whether postoperative cognitive changes are associated with changes in neurogenesis correlates and in neurotrophic factors levels, and whether this association is mediated by changes in pain, mobility, and satisfaction, and 3- explore the association between coping strategies/expectations as measured by the Somatic Preoccupation and Coping (SPOC) questionnaire and cognitive function, and in particular the relationship between changes in SPOC and cognitive changes from preoperative to 4-6 weeks after surgery.

Investigators will recruit 150 patients, 50 years or older scheduled for knee or hip arthroplasty 1-2 weeks before surgery (baseline) and collect information about their socio-demographics data, comorbidities, frailty, anxiety, pain, and pain medications. The SPOC questionnaire is administered at baseline and repeated at 4-6 weeks after surgery. CPSP (presence and severity) and satisfaction with surgery are measured at 3, 6, and 12 months. Cognitive / neuropsychological assessments will be administered at baseline, and 4-6 weeks, 6 months, and 12 months after surgery. Blood samples for serum and RNA expression analysis of biomarkers will be longitudinally collected with the same timeline.

Eligibility Criteria:
Inclusion Criteria:

1. aged 50 years or older,
2. scheduled for elective TKA or THA for osteoarthritis
3. able to provide informed consent.

Exclusion Criteria:

1. known history of dementia,
2. unavailability of tablet or computer with an internet connection for remote assessment,
3. patient unable to interact with a tablet or computer due to language, visual, or hearing impairment, or any severely limited mobility of the upper limb joints, OR
4. patient unable to understand spoken or written English.