Impact of overweight on the durability of Weller prostheses

Background. The goal of our research was to assess overweight as a risk factor for reduced survivability of Weller-type artificial cement hip joints. Material and methods. We studied 71 patients (26 men, 45 women) diagnosed with aseptic loosening of Weller endoprostheses. The age of the patients ranged from 62 to 87 years of life (mean 74.3 +/- 6.0), the exploitation time of the artificial hip-joints from 1 to 20 years (mean 10.4 +/- 5.2), overweight (calculated with the modified Broc's formula) from 0 to 40% (mean 20.8 +/- 7.5). These patients were divided into four groups depending on how long the endoprosthesis had lasted. We then analyzed the correlations between age, overweight, and exploitation time. Results. Overweight decreased as patient age (R2 = 0.7328) and endoprosthesis exploitation time (R2 = 0,798) increased. The highest average overweight (over 31% above accepted standards) was recorded in the group with the shortest observation time. In Group 2 (5-8 years of endoprosthesis exploitation) the average overweight was 27%, and in Group 3, 19% higher. Among the patients with the longest observation time the average overweight was small (4%). Conclusions. Increased body weight is a major risk factor for aseptic loosening of Weller endoprostheses. The exploatation time was more closely related to overweight than to the patients' age. Normalization of body weight should be regarded as a crucial factor in the prevention of aseptic loosening of Weller endoprostheses.