Department of Orthopaedic Surgery

The Department of Orthopaedic Surgery offers services and programs through the following Divisions. Use these links to directly access all our Department sites.

Sports Medicine

Basic Science Research

Understanding the biomechanics and basic science behind athletic injuries is one of the goals of the Sports Medicine Basic Science Research Group.  By understanding the molecular pathways and basic biomechanics behind different injury patterns, researchers at UCSF hope to develop techniques to improve outcomes following surgeries for conditions such as cartilage injury, rotator cuff tears, and ACL injuries.

Research from the sports medicine research group has been published in many peer reviewed journals and presented at national meetings including the 2012 AAOS Annual Meeting and the ORS Annual Meeting.  Research funding has been received from the NIH, AOSSM, OREF, and UCSF Academic Senate.


Rotator Cuff Injuries

Drs. Brian Feeley, Hubert Kim, and Xuhui Liu are evaluating the muscle changes that occur after rotator cuff tears.  Rotator cuff tears are the most common shoulder problem seen by physicians, and although small tears are treated with good surgical outcomes, larger tears are harder to treat.  One of the reasons is that the muscle undergoes characteristic changes such as atrophy (shrinking of the muscle) and fatty infiltration (the muscle changes from muscle to fat).  These changes make it harder for patients to recover good muscle function following repair.


Rotator cuff MRI showing muscle atrophy and fatty infiltration.

Current research focuses on determining the molecular changes that result in muscle atrophy and fatty infiltration after these rotator cuff tears.  They have recently found that the Akt/mTOR pathway, an important pathway in muscle size regulation, may be important in controlling these changes. Future studies will look at how to modify this pathway and others to improve the muscle function after rotator cuff tears.



Sports medicine researchers are using novel biomechanics tools to evaluate injury patterns and different reconstruction techniques following ACL reconstruction.  Drs. Jeffrey Lotz and Brian Feeley are using hese techniques  to test new developments in ACL reconstruction techniques, evaluate outcomes knee injuries, and be useful in evaluating new treatment strategies for knee ligament injuries.


Cartilage Injury and repair

The distinctive physical properties of bone and cartilage are essential for their function in the skeleton. Cartilage withstands loads of up to ten times the weight of the body and endures approximately one million walking cycles per year. Nature’s engineering is at its best in bone, which is remodeled throughout life to help the body adapt to changing mechanical loads while resisting fracture. However, we have much to learn about the mechanisms by which bone and cartilage cells are directed to produce tissues with these remarkable physical characteristics.


The development of post-traumatic arthritis following intra-articular fracture (fractures that go through the joint) remains an unsolved problem facing orthopaedic surgeons.Hubert Kim, MD, PhD, is studying the role of programmed cell death, or apoptosis of the chondrocyte (cartilage cell), in the development of post-traumatic arthritis. His lab has discovered that high levels of chondrocyte apoptosis occur following fractures that go through the joint in humans. Currently, his research group is using a variety of techniques to identify specific regulators of apoptosis that may contribute to early cartilage degeneration following these complicated injuries. They have developed models of chondrocyte apoptosis and are using these models to study specific apoptosis pathways. Dr Kim’s group has found that a number of potential anti-apoptotic agents, including growth factors and caspase inhibitors, can block chondrocyte programmed cell death. Their ongoing studies are testing the hypothesis that these and other agents can be combined to more effectively limit chondrocyte loss and limit cartilage degradation, thereby leading to a better outcome following these injuries.


For more information regarding these and other basic science studies, contact