Patient recruitment and study protocol

The retrospective study with prospectively collected data was conducted at the Arcus Sportklinik, Germany between April 2016 and May 2020. All patients who presented an ossification of the posterior capitellum were included. Patients reported of severe pain and a restriction in range of motion, which did not allow them to perform their sports anymore. The inclusion criteria were: (1) athletes involved in overhead sports (e.g., handball, volley ball, tennis, badminton, etc.) and boxing, (2) age 16 to 50 years, and (3) clinical and imaging evidence of an ossification at the posterolateral aspect of the elbow. The exclusion criteria were: (1) prior elbow surgery, (2) pain onset after a distinct trauma, (3) axial deformities of the elbow, (4) uncontrolled disease, such as diabetes or infections, (5) neoplasm, and (6) advanced elbow osteoarthritis.

New bone formation of the elbow was evaluated using different imaging modalities, including plain radiographs, MRI, and CT sequences. The presence of bone marrow edema, bone spur formation, adherence of the ossification to the underlying bone (stable vs. unstable), and its general localization were also investigated. Patient charts and histories were analyzed for patient demographics and prospectively collected. Histological examination was performed in three patients after resection of the ossification.