Persistent postsurgical pain in hip fracture patients. A prospective longitudinal study with multifaceted assessment.

Background: Some patients with postoperative hip fractures (HF) experience persistent severe pain. In this longitudinal study, we examined the characteristics of patients with persistent pain after HF surgery, and the factors influencing pain intensity.

Methods: We conducted an 8-week prospective study in patients with postsurgical HF. Verbal rating scale (VRS), and multifaceted outcomes, including pressure pain threshold (PPT) (affected site and biceps), were evaluated at 2, 4, and 8 weeks postoperatively. Patients were divided into mild (VRS ≤1) and severe (VRS ≥2) groups according to pain intensity at 8 weeks postoperatively. Statistical analyses were performed using two-way ANOVA and decision-tree analysis.

Results: VRS, PPT at the affected site and biceps, and physical activity (PA) time were significantly lower in the severe group than in the mild group 2 weeks postoperatively. VRS, PPT at the affected site, pain catastrophizing (PCS)-13, and the Tampa Scale for Kineshiophobia (TSK)-11 did not show significant improvements in the severe group. Decision tree analysis revealed that the VRS and PCS-13 at 4 weeks, PA time at 2 weeks, and TSK-11 change between 4 weeks and 2 weeks were factors influencing severe pain intensity at 8 weeks after HF surgery.

Conclusion: Persistent severe pain after HF surgery was characterised by high peripheral and central sensitisation, pain catastrophizing, and reduced PA at 2 weeks after HF surgery. In addition, early pain intensity, pain catastrophizing, and PA may be hierarchically influential factors for persistent pain 8 weeks after HF surgery.