A second generation hip screw was designed in the laboratory to allow unlimited immediate weight-bearing in elderly patients with cervico-trochanteric fractures. The use of this device in 300 operated patients demonstrated that it provided the same capacity for weight-bearing as total hip prostheses, but with a lower morbidity and better and longer lasting functional results. Thus, in patients with a mean age of 77 years, one half of whom suffered from an unstable fracture: the operation was minimally traumatic (reduction on an orthopaedic table, no surgical access to the fracture site, operating time less than one hour); complications were consequently rare (no deep sepsis, no dislocation) in contrast with 5 to 10% of deep sepsis or dislocation with prostheses; early unlimited weight-bearing was permitted by the 5th day in every case and was achieved by the 10th day in more than 80% of cases (30% of whom were able to walk unassisted with crutches); an essential point, the design of the material prevented dismantling on weight-bearing and preserved the morphology of the hip (telescoping of the fracture site never exceeded 20 mm, mean:11 mm). Consolidation was obtained in every case by 6 to 8 weeks. The mortality at 3 months was identical to that observed with prostheses (18%, related to physiological age). The length of hospital stay and the duration of rehabilitation were considerably shortened, as 37% of patients returned to their previous residence by the 45th postoperative day. This resulted in a marked saving in medical costs for each patient (as patients previously returned home after an average of 145 days).(ABSTRACT TRUNCATED AT 250 WORDS)