Treatment of Infection Associated with Segmental Bone Loss in the Proximal Part of the Femur in Two Stages with Use of an Antibiotic-Loaded Interval Prosthesis*

Treatment of an infection at the site of a total hip replacement associated with extensive loss of the proximal part of the femur is a challenging problem. In the present preliminary report, we describe the results after use of a prosthesis of antibiotic-loaded acrylic cement (PROSTALAC) in thirty such hips. The purpose of the prosthesis, which acts as an internal splint, is to maintain the length of the femur as well as the range of motion of the joint and the mobility of the patient between stages. A local level of antibiotics is maintained by the antibiotic-coated surface. A PROSTALAC with a cement-on-cement articulation was used in the first fifteen hips (Group I) in the study, and a custom metal-on-polyethylene articulating PROSTALAC was inserted in the subsequent fifteen hips (Group II). One patient who had a recurrent infection was managed with a second two-stage exchange and was included in both groups. Between stages, the average limb-length discrepancy was twenty-five millimeters despite a loss of more than 25 per cent of the femur in nineteen limbs. Sixteen patients were discharged home and seven, to a community hospital between stages. Six patients in Group I and only one in Group II were hospitalized for the entire course of treatment. The total duration of hospitalization for both stages averaged thirty-eight days. Twenty-eight patients were mobile even though they did not bear weight on the involved limb between stages: three patients used a cane, fifteen used crutches, and ten used a walker. Twenty-six patients reported no, slight, or moderate pain in the thigh, groin, or buttock between stages. The average Harris hip score before the first stage of the operation was 23 points (range, 0 to 63 points), which improved to 74 points (range, 40 to 91 points) at an average of forty-seven months (range, twenty-four to 114 months) postoperatively. Two patients died of unrelated causes before two years (the minimum follow-up period) had elapsed and were excluded from the final analysis; they had no evidence of recurrent infection. Of the remaining twenty-eight hips, twenty-seven (96 per cent) had no evidence of infection at the most recent follow-up examination.