Bone stretching

A device that could help repair skeletal malformations has been developed by Helsinki University of Technology (TKK) alongside the Orton Invalid Foundation in Finland.

Based on bone marrow nailing, the system works by placing a nail in the long bone of an artificially fractured limb and slowly extending it. The bone’s normal healing process means that new bone will grow in the fracture cleft, thus lengthening the limb.

Describing the system, researcher Antti Ritvanen, said: ‘The nail does not contain electronics; rather its operation is based on achieving lengthening by the innovative use of a smart material that reacts to a magnetic field. The benefits of the technology are a high degree of reliability, controllability, cost-efficiency and patient friendliness.’

Juha Haaja added: ‘Four times per day, the patient places his foot on an automatic home care device that produces a magnetic field, at which time, a daily stretching of about one millimetre is divided into smaller steps. Lengthening can be carried out painlessly at home, even while lounging on the sofa, and only takes a few minutes of the day.’

In addition to being more cost effective, the technology claims to avoid the risk of infection and scarring associated with the traditional method of using a frame on the outside of the limb to lengthen the bone. Its developers also claim that it reduces the need for after care and avoids complications involved with fractures in the new bone.

The research team, which is made up of bioadaptive students at TKK, were awarded third place in the Venture Cup business plan competition, under the name the Synoste group. The group is currently working alongside Orton’s medical director Dietrich Schlenzka and surgeons at Helsinki University Central Hospital’s Cleft Lip and Palate Centre to develop technology that can be used in the treatment of children’s scoliosis and deformities in the area of the face and skull. Clinical trials for the current system are expected to begin as early as next year.