The use of 3D-printed endoprosthesis has been proposed as a viable limb-salvage procedure following total calcanectomy in patients with calcaneal malignancy. However, certain drawbacks persist concerning the prosthetic design. In this case series, we designed a modular endoprosthesis incorporating a novel drainage system, aiming to improve the functional outcomes and to promote wound healing.We retrospectively analyzed patients with calcaneal malignancy who underwent 3D-printed modular endoprosthesis reconstruction. Clinically, we evaluated functional outcomes using the 10-cm visual analog scale (VAS) score, the 1993 version of the Musculoskeletal Tumor Society (MSTS-93) score, and the American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score. Complications were also recorded.Five male patients met the final inclusion criteria. The median age was 20 years (range 13-47 years). The median follow-up time was 28 months (range, 13-65 months). Median postoperative functional MSTS-93, VAS, and AOFAS scores were 27 points (range, 25-29), 0 points (range, 0-1), and 86 points (range, 83-93), respectively. Wound healing was observed in all patients, and there were no complications related to the endoprosthesis at the last follow-up.The use of 3D-printed modular endoprosthesis was associated with satisfactory short-term outcomes in patients undergoing calcaneal reconstruction. The incorporation of a novel design featuring an integrated draining system has the potential to enhance wound healing and expedite functional recovery.Level IV, case series.