The present invention is based on that local administration of strontium ions in bone tissue has been found to improve the bone formation and bone mass upon implantation of a bone tissue implant in said bone tissue. In particular, the invention relates to a bone tissue implant having an implant surface covered by an oxide layer comprising strontium ions and a method for the manufacture thereof. A blasting powder comprising strontium ions, a method for locally increasing bone formation, and the use of strontium ions or a salt thereof for manufacturing a pharmaceutical composition for locally increasing bone formation are also provided by the present invention.