TREATMENT OF INFECTION ASSOCIATED WITH SEGMENTAL BONE LOSS IN THE PROXIMAL PART OF THE FEMUR IN 2 STAGES WITH USE OF AN ANTIBIOTIC-LOADED INTERVAL PROSTHESIS

Treatment of an infection at the site of a total hip replacement assoc iated with extensive loss of the proximal part of the femur is a chall enging problem. In the present preliminary report, we describe the res ults after use of a prosthesis of antibiotic-loaded acrylic cement (PR OSTALAC) in thirty such hips. The purpose of the prosthesis, which act s as an internal splint, is to maintain the length of the femur as wel l 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 anti biotic-coated surface. A PROSTALAC with a cement-on-cement articulatio n was used in the first fifteen hips (Group I) in the study, and a cus tom metal-on-polyethylene articulating PROSTALAC was inserted in the s ubsequent fifteen hips (Group II). One patient who had a recurrent inf ection was managed with a second two-stage exchange and was included i n both groups. Between stages, the average limb-length discrepancy was twenty-five millimeters despite a loss of more than 25 per cent of th e femur in nineteen limbs. Sixteen patients were discharged home and s even, to a community hospital between stages. Six patients in Group I and only one in Group II were hospitalized for the entire course of tr eatment. The total duration of hospitalization for both stages average d thirty-eight days. Twenty-eight patients were mobile even though the y did not bear weight on the involved limb between stages: three patie nts 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 f irst stage of the operation was 23 points (range, 0 to 63 points), whi ch improved to 74 points (range, 40 to 91 points) at an average of for ty-seven months (range, twenty-four to 114 months) postoperatively. Tw o patients died of unrelated causes before two years (the minimum foll ow-up period) had elapsed and were excluded from the final analysis; t hey had no evidence of recurrent infection. Of the remaining twenty-ei ght hips, twenty-seven (96 per cent) had no evidence of infection at t he most recent follow-up examination.