The Latest in ACL Tissue Engineering

In this report doctors review the latest developments with tissue engineering for ligaments. The anterior cruciate ligament (ACL) of the knee is the main target. They also describe a new three-dimensional (3-D) model they are using at the University of California (Los Angeles) to study ligament engineering.

ACL repair has come a long way in the last 30 years. There's a 90 percent success rate now. Athletes are even able to return to their former level of competitive play. But problems persist. For some patients, knee pain, weakness, and loss of motion leave them unhappy with the results.

So scientists keep working on finding a good synthetic graft ACL substitute. The first step is to study and understand how normal ligaments heal when injured. The authors describe what is currently known about this process. The hope is to find a way to provide a pathway for ligament healing instead of using a synthetic replacement.

Ligament engineering may depend on finding repair cells that can build a scaffold (base structure) for regrowth of the ruptured ACL. A second option would be to use a synthetic substitute as the base and get replacement cells to fill in around it.

The various types of cells, growth factors, and scaffolds that might work are under investigation and reviewed briefly. Studies are still in the experimental phase using rabbits and mice. The final result must be a ligament that can withstand forces and loads typical in the knee under normal circumstances and during athletic play.