Our practice was started in 1979 in Northeast Philadelphia, by Dr. William Markmann, as a General Orthopaedic practice with a specialty interest in Joint Replacement and Hand Surgery. Hospital staff privileges were obtained at Jeanes Hospital and Holy Redeemer Hospital, and have been maintained to this day. The main office was moved into Jeanes Physician office building in 1981.

Dr. William Hamilton, having spent the first nine years of his practice in an academic setting, joined the practice in 1985. He brought an expertise in Sports Medicine and in Foot & Ankle.

Dr. Walter Dearolf finished his training in 1987, and brought additional training in Sports Medicine and an evolving interest in Joint Replacement.

Up until this time, there were very few programs available for Fellowship specialization. Therefore, most Orthopaedists from this era were trained as General Orthopaedists, capable of doing most procedures. Most, however, developed an interest/expertise in a specific field of Orthopaedics.

In 1988, we opened our office in Rockledge to incorporate Physical Therapy, and eventually Hand Therapy and DEXA scanning into our practice.

Dr. John Beight completed a fellowship in Joint Replacement before joining the practice, bringing additional expertise in Joint Replacement and an interest in Fracture Care.

Dr. Ellen Maitin, having completed a Fellowship in Hand Surgery, had been in practice for several years before joining us. She possessed expertise in Hand Surgery.

In the early 2000s, both Dr. Hamilton and Dr. Maitin decided to stop operating and now practice office Orthopaedics. This helped us further create an experienced office practice to provide expertise of care and continuity in the office.

Also in the early 2000s, we accepted staff positions at the Holy Redeemer Ambulatory Surgery Center, and at the Huntingdon Valley Surgery Center. This enhanced our capability to perform outpatient surgery.

Dr. Emily Abramson-Chen joined the OSRA team in 2014 with a focus on non-surgical treatments for sports injuries in both adults and youth.

Dr. Michael Kimball joined OSRA in 2014 bringing in additional expertise in the treatment of foot and ankle injuries.

In 2019, in partnership with Holy Redeemer Health System, we expanded again with offices in Abington and Richboro.

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4 Convenient Locations


7500 Central Ave, #108
Philadelphia, PA 19111


888 Fox Chase Road
Rockledge, PA 19046


1468 Old York Rd
Abington, PA 19001


910 2nd Street Pike, #202
Richboro, PA 18954

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