Purpose: The purpose of this population-based study was to clarify the incidence of knee pain by use of ultrasound (US).
Methods: Medical check-ups were conducted for residents of a mountain village in Japan. The subjects were 149 males and 252 females (802 knees) with a mean age of 63.5 ± 12.5 years. US was used to evaluate the medial joint space of both knees, with and without weight-bearing. For each patient, medial radial displacement of the medial meniscus (MRD) and number of osteophytes were evaluated. A questionnaire was used to determine whether the subjects were currently experiencing knee pain while walking, climbing stairs, or resting that had lasted more than one month. A visual analog scale was used to assess knee pain. The subjects were divided into two groups, those with knee pain (P group) and those without knee pain (non-P group), on the basis of whether a visual analog scale (VAS) was less than or more than 20 mm during walking, climbing stairs, or resting. Logistic regression analysis was used to identify the factors associated with knee pain.
Results: Significantly different weight-bearing MRD (WMRD), osteophytes, and pain while walking, climbing stairs, or resting (p < 0.01) were found between the two groups. Logistic regression analysis showed that WMRD was significantly associated with knee pain during walking or while climbing stairs.
Conclusion: We found that WMRD was significantly associated with knee pain while walking or climbing stairs, which are weight-bearing activities. On the basis of the findings of this study, we believe US is a useful tool for evaluating the factors associated with knee pain in a population-based study.
Level of evidence: Level III.