Nurse Practitioners and Physician Assistants
Our skilled nurse practitioners and physician assistants aid in the evaluation and treatment of a variety of orthopaedic issues.
Nurse Practitioner
Emily Holloway, CRNP
Emily joined the OACM family in January 2019 as a Nurse Practitioner. Emily works closely with Dr. Michael DeMarco and Dr. Gurtej Singh to provide optimal patient care regarding back pain. Together we strive to obtain an accurate diagnosis, explain a wide variety of treatment and management options, and minimize the use of opiates for chronic pain.
Prior to working as a Nurse Practitioner, Emily was an Orthopaedic/Trauma and Orthopaedic Spine Registered Nurse at Johns Hopkins Hospital. During that time, she served as a Primary Nurse Leader, Charge Nurse, Preceptor, SuperUser for EPIC, and Patient Advocate.
In her spare time, she enjoys reading, being outdoors, spending time with family and friends, and traveling. Emily’s goal is to provide excellent and quality care through thorough evaluation, examination, and treatment.
Education
- Bachelor of Science in Nursing, West Virginia University School of Nursing, 2012
- Master of Science in Nursing, Johns Hopkins University School of Nursing, 2017
Anne Maria Marete, CRNP
Anne Maria joined OACM in January 2023 as a nurse practitioner. She works with Dr. Singh and Dr. DeMarco to care for patients with chronic back and neck pain. Her goal is to provide her patients with comprehensive, effective, and evidence-based care.
Prior to joining OACM, Anne Maria worked in pain management. Before becoming a nurse practitioner, she worked at Medstar Georgetown University Hospital in the medical, surgical and neurosurgical ICUs as a float ICU nurse. During her education and training at University of Maryland she conducted a doctoral project that focused on implementing a depression screening protocol for patients with chronic pain.
During her spare time, Anne Maria enjoys doing activities outdoors, spending time with family and friends, and volunteering at community outreach programs.
Education
- Doctor of Nursing Practice, University of Maryland School of Nursing, 2021
- Bachelor of Science in Nursing, University of Maryland School of Nursing, 2016
- Associates Degree in Nursing, Montgomery Community College, 2012
Angeline Williams, CRNP

- Associate of Science in Nursing, Baltimore City Community College, 2006
- Bachelor of Science in Nursing, Walden University School of Nursing, 2014
- Master of Science in Nursing, Walden University School of Nursing, 2018
Physician Assistants
Justin Baker, PA-C
Justin Baker joined the Orthopaedic Associates of Central Maryland family in 2022 to serve as a physician assistant to Dr. M. Brian Polsky. His goals are to focus on helping each and every patient achieve their personal goals—whether that be a return to sports or finally being able to walk without pain—and to return them to as active a lifestyle as possible.
Prior to joining OACM, Justin served in the United States Army Reserve as a Combat Medic Specialist, then completed a Bachelor of Science degree in Exercise and Sports Science.
Those experiences, combined with his love of sports, opened his eyes to the world of orthopaedics, and he then went on to complete a Master of Science degree in Physician Assistant Studies. Working in orthopaedics has given him the opportunity to help improve our patients’ quality of life, which he looks forward to doing every day.
He lives in Baltimore with his wife, and in their free time they enjoy traveling the world.
Education
- Master of Science in Physician Assistant Studies, Mary Baldwin University, Virginia, 2022
- Bachelor of Science in Exercise Science, University of North Carolina at Pembroke, North Carolina, 2019
Sean McGiveron, PA-C
Sean McGiveron joined the Orthopaedic Associates of Central Maryland family in 2019 to serve as a physician assistant to Dr. Scott Silverstein.
Prior to completing his physician assistant certification, Sean earned a degree in exercise science, where he gained experience evaluating musculoskeletal conditions. The combination of his academic work and hands-on experience gained as a medical assistant for OACM prior to beginning his graduate education, enables Sean to assist Dr. Silverstein in the evaluation and treatment of a variety of orthopaedic conditions.
In his personal time, Sean enjoys being outdoors, playing ice hockey, skiing, and traveling. As a Buffalo native, he is an avid fan of the Bills and Sabres.
Sean’s goal is to provide patients with great evaluations, explanations, and education, so that together the best treatment plan can be created, ensuring the highest quality of life.
Education
- Bachelor of Science in Exercise Science, University at Buffalo, New York, 2015
- Master of Science in Physician Assistant Studies, Long Island University, New York, 2018
Patient Information
Key information when having a Joint Replacement with Dr. Silverstein
Michael Miller, PA-C
Michael Miller serves as a physician assistant to Dr. Xie. His goal is to have a patient-centered care approach, spending as much face-to-face time with patients as possible. He also aims to educate patients about their condition, while presenting both the conservative and surgical options available.
Prior to joining OACM, he completed a Bachelor of Science degree in Kinesiology. He then worked as a strength and conditioning coach for athletes, owned his own strength and conditioning company, and served as an assistant strength coach for the Baltimore Ravens for the 2004-2005 season.
In 2014, he completed a Master of Science degree in Physician Assistant Studies, and taught orthopaedics for the Towson University PA program. He has participated in the annual American Association of Hip and Knee Surgeons (AAHKS) as a faculty member and presenter for the team course for hip and knee replacements, and worked for a high-volume hip and knee surgeon for the last 8 years.
He resides in Howard County, Maryland with his wife, three children, and two dogs. In his free time, he enjoys home improvement, coaching youth sports, working out, and spending as much time outside as possible.
Education
- Master of Science in Physician Assistant Studies, Towson University, 2014
- Bachelor of Science in Kinesiology, University of Maryland College Park, 2005
Aaron Shakespeare, PA-C
Aaron Shakespeare has been working with Dr. Sam Sydney since 2002. Prior to completing his physician assistant certification, he worked as an orthopaedic physical therapist. As a PT, Aaron gained a tremendous amount of experience evaluating and treating musculoskeletal conditions, which enables him to assist Dr. Sydney in the evaluation and treatment of a variety of orthopaedic issues and seamlessly guide patients through the rehabilitation expectations of their condition.
Aaron’s goal is to provide all patients with the highest level of communication and education to help them choose a treatment plan that will allow them the highest quality of life.
Education
- Bachelor of Science in Rehabilitation, West Virginia Wesleyan College, 1994
- Bachelor of Science in Physical Therapy, West Virginia University, 1996
- PA Certification, Towson University/CCBC-Essex, 2002
Evan Taxin, PA-C
Evan Taxin joined the Orthopaedic Associates of Central Maryland family in 2020 to serve as a physician assistant to Dr. Khurram Pervaiz in treating conditions of the hand and upper extremities.
Before joining our practice, Evan earned a Bachelor’s degree in Kinesiology from Towson University. His passion for orthopaedic medicine grew during medical training at Eastern Virginia Medical School’s Master of Surgical Assistant program. It was also here where Evan earned the “Director’s Award,” recognizing his dedication to academic excellence and compassionate care in the operating room. He completed his physician assistant training at Philadelphia College of Osteopathic Medicine and has spent the last three years working as a physician assistant in Orthopaedic Surgery.
In his free time, Evan enjoys spending time outdoors with his family and French bulldog, exercising, and traveling. He is a native of the Philadelphia area and is an avid fan of the Flyers, Phillies, and Eagles.
Evan strives to provide each patient with the highest level of service through effective communication, education, and compassionate care.
Education
- Bachelor of Science in Kinesiology, Towson University, 2008
- Master of Science in Surgical Assistant Studies, Eastern Virginia Medical School, 2014
- Master of Science in Physician Assistant Studies, Philadelphia College of Osteopathic Medicine, 2016
Kristin Thomas, PA-C
Kristin Thomas joined the Orthopaedic Associates of Central Maryland family in 2015 to serve as a physician assistant to Dr. Brian Polsky and Dr. Nicholas Grosso.
Prior to completing her physician assistant certification, Kristin earned a degree in athletic training, gaining an incredible amount of experience evaluating and treating sports-related musculoskeletal conditions on and off the field. This experience, along with her experience as an orthopaedic technician prior to her graduate education, allows Kristin to assist both Dr. Polsky and Dr. Wallace in the evaluation and treatment of a variety of orthopaedic conditions.
Kristin’s goal is to provide patients with the highest level of care, service, and education, as well as an effective treatment plan that will allow for the highest quality of life.
Education
- Bachelor of Science in Athletic Training, University of Charleston, West Virginia, 2005
- Master of Science in Physician Assistant Studies, Towson University, Maryland, 2009