The concern on clinical use of recombinant human bone morphogenetic protein-2.

Sir,

The recent publication on the recombinant human bone morphogenetic protein-2 (rhBMP-2) is very interesting.[1] Hamilton et al. concluded that “100% fusion rate was achieved with adjunct use of rhBMP-2, with a safe and effective average rhBMP-2 dose of 2.38 mg per level.”[1] Indeed, the use of rhBMP-2 is a new approach and the important concern is on the supporting evidences on this technique.[2] In this work, the total number of subjects is small; however, it can be a good supporting evidence. Another important concern is on the adverse effect of using this technique. Addullah et al. noted for the necessity on good examination with regard to side effect profiles.[2] Taghavi et al. noted that the “utility is limited by cost, and potential dose-dependent risks, such as local inflammatory reactions and ectopic bone formation.”[3] An important side effect that is observed in the animal model studies is “joint space obliteration caused by cartilage overgrowth.”[4] This has to be systematically evaluated in the long-term follow-up.