The influence of operative morbidity on clinical long-term results is evaluated in a prospective study employing a consecutive series of 120 patients (mean age, 82.5 +/- 4.7 years) with operatively treated fractures of the coxal femur. Perioperative complications which were observed in 37.5%, with a predominance of urinary tract infection (n = 26), bronchopneumonia (n = 16) and cardiac decompensation (n = 4), were significantly associated with a pertrochanteric fracture localization (p < 0.05), prolonged latency from trauma to surgery (p < 0.01), and a prevalence of three and more internal diseases (p < 0.01). At 1-year follow-up patients with a perioperative complication had a significantly worse performance scoring (p < 0.01) than individuals with an unimpaired perioperative course. This leads to the conclusion that perioperative morbidity decisively influences functional outcome in the elderly patient.