The number of complicated bone fractures is growing: In older people especially, and despite appropriate therapy, the healing of fractures is often delayed or not successful at all. Possible solutions were presented by German researchers at the 13th Congress of the European Federation of National Associations of Orthopaedics and Traumatology (EFORT) in Berlin.
Open fractures, tumors and osteoporosis worsen chances
Complications after fractures and insufficient progress in healing occur particularly when the bone biology is disrupted. This happens in every third patient in the case of third degree, open fractures. In cases involving infection, 40% are affected, and after tumor surgery and radiation therapy to the bone, disruption occurs in up to 80% of the cases. But osteoporosis is also a major risk factor: Reduced metabolism slows down the remodeling and healing process, so that every fifth bone fracture heals poorly in patients with bone atrophy. "Because of increased life expectancy, such cases that were rarities just a few years ago have increased significantly and will increase even more in the future," Prof Schmidmaier predicted.
Current techniques unsatisfactory
If bone defects still fail to heal up even after six months, and if the fractured edges keep moving against each other, one speaks of “nonunions” or “pseudarthrosis.” A further stabilisation of the bone with implants usually helps when the cause is due to mechanical reasons, whereas the complexity increases significantly following an infection and when the cause is biological. Less pronounced “pseudarthrosis” has been treated with bone marrow from the patient’s pelvis, but this often results in pain at the extraction point. In cases involving fractures of more than two centimetres, ring fixators are frequently used to stretch the bone - a very long and complicated process with uncertain prospects for success.
Proteins replace fixation
New approaches focus on growth factors to promote bone healing. "This involves the body's own proteins, which can be produced synthetically today. When combined with bone and stem cells, this can also heal large bone defects as well as damage following an infection. It has the advantage that the patient usually does not require any more fixations," the expert explained. These growth factors are already being employed in clinical practice, particularly in those patients who already have experienced many unsuccessful attempts at therapy and surgery.
Success in nine out of ten patients
One to two operations - depending on the size of the bone defect - are required for the application of growth factors. "For very large fractures or after an infection, the diseased bone is first removed in the initial operation. Then a new periosteum is grown using bone cement prior to a second surgery in which the defect is filled with cells and growth factors," Prof Schmidmaier continued. The goal: Patients should be able to put their full weight on their leg after a few weeks with all implants beneath the skin. This had been achieved in 88% of the 400 patients who were treated in Heidelberg.
Bioactive implants induce healing
The Heidelberg expert hopes for future advances through further research on bioactive implants. "Active substances can also be released from the surface of implants, in predetermined time sequences, provided that the implants are coated appropriately," Prof Schmidmaier reported at the EFORT Congress in Berlin. Pieces of genetic information with the genetic blueprint for growth proteins could thus stimulate the cells around bone defects to construct their own proteins and thereby set in motion the bone healing process. Success seems within reach: This delivery technique is already in clinical use involving antibiotics.
