Stem Cells

Stem Cells for Non-union

Background
Slow bone healing affects almost 20% of tibial fractures (Oni and
Gregg, 1988). In some cases these become established non-unions with
significant pain and loss of ability to walk. For these patients
infection also becomes a superimposed possibility as they undergo
repeated operations in an attempt to obtain healing. Usually they are
unable to work and due to being unemployed for several years, often
lose the skills and motivation to ever return to full-time employment.

Bone grafting is the usual method of treatment but is not effective in
all patients. In some cases bone transport in a circular frame may be
appropriate in a shortened or infected fracture. The residual
patients are the ones who urgently need an improved alternative method
of treatment.

Mesenchymal Stem cells (MSCs) are stored by the body in the bone marrow
as a natural reserve source of cells for bone healing. Culture of
these cells is relatively straightforward and has been used for the
formation of bone in animal studies (Ashton et al., 1980) and in
patients (Quarto et al., 2001), and the treatment of infection
(Belfast MD, 1997). This study intends to widen the scope of cell
transplantation to include bone. (These techniques are autologous: it
is taking the patients' own cells, grown in their own serum, and
returning them to the same patient).

Technique
A first operation (which can be carried out under local or general
anaesthetic) simply inserts a needle into the back of the pelvis to
draw out stem cells. In one way it is simple, but there is a lot of
variation in the success between surgeons. The blood and cells
aspirated are taken to the laboratory where the specialised
bone-forming stem cells are separated out. Often as few as 20 cells
are found. The cells however are able to double in number every day or
two, so after 3 weeks there are several million cells.

The second operation varies depending on what needs to be done for the
fracture. Sometimes the fracture needs to be reset. Often the
operation is quite a small one and bone graft substitute developed by
Biocomposites is used to graft the fracture site, first raising the
periosteum by decortication. Graft is inserted on one side with just
serum, and on the other side with the cells. The reason or doing this
as part of a randomised controlled trial is to test that the cells
really do make a difference. The wounds are then suured. Full
weight-bearing is then usually the best thing for the fracture,
although often after 4 weeks I will ask patients to limit activity or
8 weeks while the new bone consolidates.

Follow-up
Every two months a CT scan is undertaken with a phantom to assess the
new bone formation and compare the two sides.

Results
Patients are making excellent progress and now 24 have been treated.
Most have had several operation before in an attempt to get the
fracture healed. 12 of the first 14 patients have healed.