Clinical and sociodemographic factors associated with the location of nociceptive pain in the femur/tibia and ankle in patients treated at the Pain Clinic of the Luis Guillermo Ibarra Ibarra National Rehabilitation Institute

Abstract

Introduction. Pain is one of the most underestimated and underdiagnosed health problems in the world. The International Association for the Study of Pain (IASP) defined pain as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage.” Nociceptive pain is usually classified into two broad categories: somatic pain and visceral pain. Somatic nociceptive pain is a type of pain that arises from the direct stimulation of nociceptors located in somatic structures such as skin, muscles, bones, and joints, while visceral pain is more diffuse and is related to the involvement of internal organs. Somatic nociceptive pain does not involve neurological injury, but rather originates from damage or inflammation of peripheral tissues, which activates pain transmission pathways to the central nervous system. It is one of the main reasons for consultation in clinics. Although it is usually located in regions such as the lumbar spine or major joints, pain in the femur, tibia, and ankle is less common but clinically relevant, especially when it affects the patient's functionality and quality of life.

Various clinical factors such as the origin of the pain, age, and body mass index, as well as sociodemographic factors such as gender and occupation, can influence the anatomical distribution of pain, its intensity, and its evolution. Identifying these factors is key to designing personalized assessment, prevention, and treatment strategies.

Objective. To analyze which clinical and sociodemographic factors are associated with the anatomical location of nociceptive pain.

Methodology. Cross-sectional observational study of 125 patients admitted to the INR LGII Pain Clinic between February 1, 2024, and February 1, 2025. Patients were divided into two groups: A. With pain located in the femur/tibia/ankle and B. Other locations. The comparison of proportions between the groups was analyzed with chi-square and means with Student's t-test for independent samples. A p (< 0.05) was considered significant.

Results. The prevalence of pain localized in the femur/tibia/ankles was 10.4%. Compared to women, men had an OR = 2.7 (p = 0.08) for pain localized at this level, students compared to other occupations had an OR = 7.8 (p = 0.03), cancer pain had an OR = 24.9 (p <0.001), the mean age of patients with pain located at these levels was 43.9 +/- 24.2 years versus 59.4 +/- 19.5 (p = 0.009), and the Body Mass Index was 23.9 +/- 4.9 versus 28.3 +/- 5.6 (p = 0.008).

Conclusions. Somatic nociceptive pain located in the femur/tibia/ankle is strongly associated with cancer pain, with a higher risk for males of working age and normal BMI.

Keywords: Location, pain, nociceptive