Simple SummaryPrimary bone sarcomas around the distal humerus are rare. Following tumor resection, distal humeral replacement (DHR) is a limb-salvage option for the reconstruction of the resulting bone defect. Due to small patient numbers, the postoperative functional outcome and resumption of sporting activities among affected patients remain mostly unclear although they become increasingly important with improvements in patients’ life expectancy and quality of life. Thus, the aims of our study were to evaluate the functional outcome, assess the return to sport activities, and identify the potential limiting and beneficial factors in a large homogenous patient cohort treated with a single-design modular implant at a tertiary sarcoma center.AbstractDistal humeral replacement (DHR) is a limb-salvage option for the endoprosthetic reconstruction of bone defects following the resection of a primary bone sarcoma. As primary bone sarcomas are only occasionally located around the distal humerus, there is a paucity of information regarding postoperative function, and patients’ resumption of sporting activities. With advances in diagnostics and in surgical and oncological treatment leading to an increased patient life expectancy and higher quality of life, patients’ functional outcome and return to sports activities are of increasing interest. Between 1997 and 2021, a total of 24 patients underwent DHR with a single-design modular implant at a tertiary sarcoma center. A total of 14 patients who died of their disease were excluded, leaving a study cohort of 10 patients, with a median age of 30 years on the day of surgery (IQR 20–37). At the last follow-up, after a median of 230 months (IQR 165–262), the median MSTS was 19 (IQR 13–24), the median TESS was 79 (IQR 66–87), the median SEV was 38% (IQR 24–53), the median TS was 6 (IQR 4–7), and the median WAS was 3 (IQR 1–8). Among the variables of gender, surgery on the dominant extremity, intraoperative nerve resection, extra-articular tumor resection, chemotherapy, radiotherapy, and revision surgeries, none were associated with a better/lower functional outcome score or return to sports activities. However, a higher level of sports performance prior to diagnosis (WAS > 10) was associated with a higher level of sports performance postoperatively (p= 0.044).