Glass ionomer cement (Ionocem) was developed for use in bone surgery and is reported to be notably biocompatible. Between 1991 and 1994 we performed revision operations for aseptic loosening of arthroplasties of the hip on 45 patients using this material in its granulate form (Ionogran) mixed with homologous bone as a bone substitute. Of these 45 patients, 42 were followed up for a mean of 42 months. Early reloosening of the acetabular component has occurred in ten after a mean of 30 months. Histological examination showed large deposits of aluminium in the adjacent connective tissue and bone. Osteoblastic function and bone mineralisation were clearly inhibited. The serum levels of aluminium were also increased. The toxic damage at the bone interface caused by high local levels of aluminium must be seen as an important factor in the high rate of early reloosening. Our findings cast doubt on the biocompatibility of this material and we do not recommend continuation of its further use in orthopaedic surgery.

Eleven patients underwent disarticulation for infected arthroplasty of the hip. Exchange total hip arthroplasty or conversion to a Girdlestone excision arthroplasty had been undertaken previously an average of 2.9 times. The indications for disarticulation were as a life-saving measure, or as a result of severe infection of soft tissue and bone, loss of bone stock, or vascular injury. While the indications for this drastic operation were highly individual, there were instances where disarticulation could have been avoided if repeated exchange operations had been eschewed in deference to a Girdlestone procedure.