[Coral as support of traumatic articular compression. A prospective study of 23 cases involving the lower limb]

Infection risk makes the management of a bone bank more and more difficult. On the other hand, realizing an autologous graft is not always without consequences. That is why we estimated the mechanical quality, the osteo-integration and the biocompatability of a coral graft.

Between 1988 and 1992, two of us systematically used coral graft as "support" after lifting of some articular depression in fractures of inferior limb. Osteosynthesis was systematically associated. In this way, we operated 13 fractures of the lateral tibial plateau, 8 thalamic fractures of the calcaneus and 2 fractures of the inferior extremity of the tibia. Average follow-up is 20 months, with extremes of 68 and 12 months. Material ablation was realized 13 times and coral graft biopsy 4 times. Bone integration was estimated radiologically in 3 stages: stage 1: non union = "margin" around the coral, stage 2: possible integration = the coral is perfectly visible, but its borders grow indistinct, stage 3: certain integration = peripheral disparition of the coral weft, radiological interpenetration between coral and bone framework. We systematically searched for secondary displacements and complications.

Mechanical conditions were respected, there was no secondary displacement. "Possible integration" (stage 2) was found in 8 cases at an average follow-up of 20 months. In 9 cases, we found "certain integration" (stage 3), at an average follow-up of 28 months. It is possible that a more important follow-up time would allow to find more integration cases. Biocompatibility is debatable under the operating conditions of the authors. We counted 5 aseptic serous flows which continued to be aseptic (1 tibial plateau, 1 inferior extremity of the tibia, 3 calcaneum). Three coral grafts were removed to obtain healing.

When biocompatibility is satisfactory the integration is certain. The longer the follow-up time, the more stage 3 cases can be observed. Nevertheless, this integration runs out with time. We did not find any explication to aseptic serous flows. It may result from some impurities. On the other hand, use of the coralin hydroxyapatite does not seem to drive to allergic complications.

In accordance with this study, we use the coral graft only in case of tibial plateau fracture. Our experience with coral graft in the other fields of bone surgery is not sufficient to express an opinion.