Journal of Pain Research (Apr 2021)

Comparison of Predisposing Factors Between Pain on Walking and Pain at Rest in Patients with Knee Osteoarthritis

  • Satake Y,
  • Izumi M,
  • Aso K,
  • Igarashi Y,
  • Sasaki N,
  • Ikeuchi M

Journal volume & issue
Vol. Volume 14
pp. 1113 – 1118

Abstract

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Yoshinori Satake,1 Masashi Izumi,1 Koji Aso,1 Yoichi Igarashi,2 Nao Sasaki,3 Masahiko Ikeuchi1 1Department of Orthopaedic Surgery, Kochi Medical School, Kochi University, Kochi, Japan; 2Department of Orthopaedic Surgery, Tosa Municipal Hospital, Kochi, Japan; 3Medicines Development Unit Japan, Eli Lilly Japan K.K., Hyogo, JapanCorrespondence: Yoshinori SatakeDepartment of Orthopaedic Surgery, Kochi Medical School, Kochi University, Kohasu, Oko-cho, Nankoku-shi, Kochi 783-8505, JapanTel +81 88 880 2387Fax +81 88 880 2388Email [email protected]: Patients with knee osteoarthritis (OA) complain of various types of pain, divided into two main categories: pain on movement and pain at rest. A thorough understanding of pain is essential for managing knee OA; however, few studies have investigated the mechanisms underlying the two different types of pain. This study aimed to clarify the predisposing factors for pain in patients with knee OA with a focus on differences between pain on walking and pain at rest.Patients and Methods: This study involved 93 patients, aged 44– 90 years, with knee OA, including 74 women. We assessed demographic variables (sex, age, body mass index [BMI], side), visual analogue scale (VAS) score on walking, VAS score at rest, Kellgren and Lawrence (KL) grade on radiograph, synovitis score and bone marrow lesion (BML) score on magnetic resonance imaging, and pressure pain threshold (PPT), and used univariate and multiple regression analyses to investigate factors predisposing patients to pain at rest or pain on walking.Results: In the univariate analyses, we found significant correlations between VAS score on walking and BMI (r=0.31, p< 0.01), KL grade (r=0.40, p< 0.01), synovitis score (r=0.26, p=0.01), and BML score (r=0.36, p< 0.01), whereas VAS score at rest correlated with PPT (r=− 0.23, p=0.02) and BMI (r= 0.26, p=0.01). Multiple regression analysis showed that significant explanatory factors for VAS score on walking were BMI (β=0.22, p=0.03) and KL grade (β=0.27, p=0.03). By contrast, PPT was the only significant explanatory factor for VAS score at rest (β=− 0.27, p=0.01).Conclusion: Predisposing factors were significantly different between pain on walking and pain at rest, indicating that different pain mechanisms exist in the two types of pain. Pain on walking was more strongly associated with mechanical and structural factors, while pain at rest was associated with mechanical hyperalgesia of the knee.Clinical Registration: University Hospital Medical Information Network Clinical Trials Registration number; 000041190.Keywords: knee osteoarthritis, pain at rest, hyperalgesia

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