Prevalence, associated factors, and short-term impact of central sensitization in high-altitude patients undergoing total knee arthroplasty.

PURPOSE

Central sensitization (CS) plays a critical role in prolonged pain and poor outcomes after total knee arthroplasty (TKA), but its prevalence and impact in high-altitude populations remain unexplored. This study aims to examine the prevalence of CS, its associated factors, and short-term postoperative outcomes in high-altitude TKA patients.

METHODS

This prospective, single-centre cohort study included high-altitude (above 2,500 m) TKA patients with primary knee osteoarthritis (OA). Central sensitization (CS) was diagnosed using the Central Sensitization Inventory (CSI), with a cutoff score of ≥ 40. Propensity score matching (PSM) was applied to balance baseline characteristics between the CS and non-CS groups. Preoperative factors, postoperative outcomes (pain levels, complications, opioid consumption, hospital stay), and the incidence of chronic pain and dissatisfaction at six months were collected and analyzed using SPSS software.

RESULTS

A total of 230 patients were included, with 36 (15.7%) classified as having CS. Multivariable logistic regression identified female gender (OR: 3.9, 95% CI: 1.0-14.3, P = 0.043), higher body mass index (BMI) (OR: 1.2, 95% CI: 1.1-1.3, P = 0.006), and residence above 4,000 m (OR: 5.1, 95% CI: 1.7-15.1, P = 0.003) as significant factors associated with CS. After PSM, the CS group had significantly worse short-term outcomes, with higher pain scores at 24, 48, and 72 h (P < 0.001), increased incidence of postoperative nausea and vomiting (PONV) (P < 0.001), longer hospital stays (P < 0.001), greater cumulative opioid consumption (P < 0.001), higher rates of chronic postoperative pain (46.9% vs. 21.9%, P = 0.014), and greater patient dissatisfaction (25.0% vs. 6.3%, P = 0.039) compared to the non-CS group.

CONCLUSION

This study found a 15.7% prevalence of CS among high-altitude TKA patients. Female gender, higher BMI, and residence at altitudes above 4,000 m were identified as factors associated with CS. Furthermore, CS was linked to worse short-term postoperative outcomes, including higher pain levels, increased incidence of PONV, greater opioid consumption, longer hospital stays, and a higher prevalence of chronic postoperative pain and dissatisfaction.