The hypothesis of a possibly diminished bony ingrowth revealed by the devel
opment of radiolucency or a radiodense line with time around a cementless f
emoral stem subsequent to indomethacin administration for prevention of het
erotopic ossification was investigated, Eighty prospective patients with in
domethacin prophylaxis were compared with 82 patients without indomethacin
prophylaxis chosen retrospectively. The same cementless implant was used in
all cases, and patients were observed clinically and radiologically for a
minimum of 6 years. The mean postoperative Harris hip score at 6 years was
91 versus 88 points, respectively, and there were significantly more excell
ent results (Harris hip score > 90) in the indomethacin group. None of the
patients underwent revision surgery, Radiologic signs such as loss of bone
density and radiodense lines were observed around the shoulder of the prost
hesis in a similar percentage in both groups. Significant subsidence of the
stem was observed in one instance in the indomethacin group and in three i
nstances in the control group. The results of this study are a strong indic
ation that indomethacin does not influence the development of radiolucency
or other radiologic changes around a cementless stem after 6 years.