Osseointegration & stress shielding

Forty-two patients with a flexible distal non-cemented grit-blast hip stem have been examined to see if distal osseointegration (OI) had occurred. The minimum follow-up was 5 years. The definition of distal osseointegration was "the exhibition of distal bone hypertrophy with proximal bone atrophy with no radiolucency in a clinically stable situation". Osseointegration was noted in 28.6%. It was seen more commonly in older females with greater canal fill, especially in the lateral x-ray. A control group in which the distal end of the stem was polished showed virtually no osseointegration. It appears therefore that with the simple expedient of polishing the distal stem, osseointegration in this zone can virtually be abolished.