BACKGROUND: To investigate the correlation between various orthopedic conditions and overweight/obesity at the Department of Orthopedics, Malmö University Hospital Sweden. Obesity is associated with numerous major medical conditions. Although the relationship between gonarthrosis and osteoarthritis and body mass index (BMI) is well recognized, other orthopedic conditions have been less well studied. METHODS: We compared the BMI of 2 orthopedic outpatient cohorts of a local community-based urban reference population. Study 1 identified the medical records of 79 consecutive emergency room patients (45 women; age 27-49 years) with the diagnosis of ankle fracture, for whom we calculated the BMI from the self-reported height and weight. Study 2 prospectively weighed and measured 647 consecutive patients (316 women, age 20-80 years) attending our orthopedic specialty clinic for various recent and chronic conditions during a 3-week period. RESULTS: The mean BMI was 1.9 units greater in the patients with ankle fractures than in the age- and gender-matched controls (P <.001). The odds ratio for a BMI >30 kg/m(2) was 3.46. The orthopedic clinic patients had a mean BMI 1.4 units greater than the reference population (P <.001), with an odds ratio of 2.3 for a BMI >30 kg/m(2) (P <.001). CONCLUSION: The results of these pilot studies have demonstrated significant relationships between obesity and common orthopedic conditions that contribute to the global excess medical expenditures attributable to obesity.