Traditionally, the orthopedist's arsenal looks much like a carpenter's. It is dominated by heavy metal -- cages, screws, saws, drills and metal implants for joints such as hips and knees.

Stem cell therapy could eventually eliminate the need for joint replacement, says professor Einhorn from the US, who last year performed his first hip replacement surgery using the patient's own stem cells.

The unspecialized stem cells can transform into cells with specific functions in the body. Adult stem cells are available from a number of sources, including bone marrow and fat.

Stem cells from a patient's own body can be used to repair bones, ligaments, cartilage, muscle, spinal cord and nerves.