[Characteristics of pain in oncologic disease of the knee].

Background: 10% of > 55-year-old adults suffer some kind of non-neoplastic knee pain and 75% of the musculoskeletal neoplastic disease develops in the knee.

Objective: to identify clinical characteristics of knee pain in neoplastic knee pathology.

Methods: after appropriate authorization of the Local Committee of Investigation and under informed consent, we made a crosssectional and a risk analysis study. We included 160 patients who were seeking medical help due to knee pain. They answered a standardized questionnaire relating to the characteristics of their pain symptomatology. Data were integrated into two groups with knee pain; a) neoplasic (cases, n = 65), b) non-neoplasic (controls, n = 95) and analyzed (SPSS v.15™). We used homogeneity tests between groups (p > 0.05); inferential analysis (Student t test, χ(2)) and risk assessment (OR), p ≤ 0.05, (CI 95%), Statistical power was > 0.80.

Results: female gender predominated (55%); age was 40.3 ± 19.6 years. The most prevalent diagnoses were knee osteoarthritis 37% for non-neoplasic group; giant cell tumor 10% for benign neoplasic group and osteosarcoma 6.1% for neoplasic malignant group. Knee pain lasting < 4 months (OR 7.6; CI 95% 3.48-16.5) and severe intensity (OR 5.7; CI 95% 2.82-11.64), constant pain (OR 2.9; CI 95% 1.37-6.36), rapidly progressive fluctuation (OR 31; CI 95% 7.01-137) and nocturnal predominance (OR 7.72; CI 95% 3.2-18.5) were characteristics of neoplasic knee pain.

Conclusions: the neoplasic knee pain was characterized for a rapid onset, severe and constant pain, progressive, fluctuation and predominantly by night-time.