Meet Our Physicians

Jay Keener, MD, Chief of Service
Dr. Keener is board-certified in orthopedic surgery and serves as an Associate Professor in Orthopedic Surgery at Washington University School of Medicine and Chief of the shoulder and elbow service. Also formerly a physical therapist, Dr. Keener specializes in shoulder and elbow arthroscopic surgery and joint replacement and also treats shoulder instability; labral tears and biceps tendon injuries; rotator cuff disease/tears; frozen shoulder; shoulder fractures; shoulder and elbow arthritis; throwing injuries; and acromioclavicular and sternoclavicular joint injuries. He earned his medical degree from West Virginia University School of Medicine. Following a residency in orthopedic surgery at the University of Iowa, Dr. Keener completed a fellowship in shoulder and elbow surgery at Washington University School of Medicine in St. Louis in 2004.

Alexander Aleem, MD
Dr. Aleem is an Assistant Professor of Orthopaedic Surgery at Washington University School of Medicine. He specializes in the surgical and nonsurgical treatment of rotator cuff tears, shoulder and elbow instability, shoulder and elbow injuries in the throwing athlete, biceps tendon injuries, frozen shoulder and arthritis of the shoulder and elbow. Dr. Aleem received his medical degree at Washington University School of Medicine in St. Louis. He completed a residency in Orthopaedic Surgery at Washington University School of Medicine and Barnes-Jewish Hospital, where he served as an Administrative Chief Resident. Dr. Aleem then went on to complete fellowship training in shoulder and elbow surgery at The Rothman Institute at Thomas Jefferson University. 

Aaron Chamberlain, MD

Dr. Chamberlain is an Assistant Professor of Orthopaedic Surgery at Washington University School of Medicine. He earned his medical degree from the University of California San Francisco School of Medicine and completed a residency in orthopedic surgery and sports medicine at the University of Washington Affiliated Hospitals. He completed a fellowship in shoulder and elbow surgery at Washington University School of Medicine, Department of Orthopaedic Surgery. Dr. Chamberlain sees patients at The Center for Advanced Medicine. Learn more about Dr. Chamberlain.

Chi-Tsai Tang, MD
Dr. Tang is an Assistant Professor of Orthopedic Surgery at Washington University School of Medicine. He specializes in non-surgical treatment of the shoulder and elbow as well as the evaluation and non-operative management of all musculoskeletal injuries including sports related injuries, medical acupuncture, fluoroscopic guided injections, electrodiagnostics, ultrasound guided injections, and injuries in tennis players. Dr. Tang earned his medical degree at the University of North Carolina at Chapel Hill School of Medicine. He completed his residency training in Physical Medicine and Rehabilitation at the University of Michigan Health System, and his fellowship in Physical Medicine and Rehabilitation Sports Medicine at Washington University School of Medicine in St. Louis.

Ken Yamaguchi, MD, Vice Chair for Quality and Research
Dr. Yamaguchi is the Sam and Marilyn Fox Distinguished Professor of Orthopedic Surgery at Washington University School of Medicine and the Vice Chair of Quality and Research in the Department of Orthopaedic Surgery. Board-certified in orthopedic surgery, Dr. Yamaguchi is consistently listed in America’s Top Doctors and Best Doctors in America. He specializes in degenerative, traumatic, and orthopedic sports disorders of the shoulder and elbow, including treatment of the rotator cuff, instability, frozen shoulder, and degenerative and rheumatic arthritis of the shoulder and elbow. Dr. Yamaguchi earned his medical degree and served a residency in orthopedic surgery at George Washington University in Washington, D.C. He completed a fellowship in shoulder and elbow surgery at Columbia Presbyterian Medical Center in New York in 1995.

Karen Holtmann, MSN, RN, ANP-C
Karen is an Orthopedic Adult Nurse Practitioner at Washington University School of Medicine. She specializes in the evaluation and non-operative management of acute and chronic shoulder and elbow conditions and injuries, including general shoulder and elbow pain, arthritis, tendonitis and frozen shoulder syndrome. Karen received both her Bachelors of Science in Nursing and Masters of Science in Nursing, Advanced Practice Adult Nurse Practitioner degree from the University of Missouri-St. Louis. Karen brings over 17 years of nursing experience to Washington University Orthopedics, and has worked in a variety of clinical settings including neurosurgery, critical care medicine and orthopedics. Most recently, she worked as an inpatient adult nurse practitioner for both the Neurosurgery and Orthopedic departments at Barnes-Jewish Hospital. In 2014, Karen was awarded Orthopedic Nurse of the Year from St. Louis Magazine's Excellence in Nursing Award, and is a member of the American Association of Nurse Practitioners (AANP).

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