Background: Reconstruction with an endoprosthesis following pelvic tumor resection has increased over the years. However, the long-term results reflect a disappointing frequency of mechanical complications and failures. In an attempt to enhance implant fixation, an electron beam melting (EBM)-based modular hemipelvic endoprosthesis was introduced. Our aim was to explore the preliminary clinical outcomes for patients who have been managed with this prosthesis.
Methods: We reviewed the records of 80 consecutive patients who had been managed at a single center between June 2015 and September 2017. Chondrosarcoma was the predominant diagnosis (31.3%). Osseous metastases were diagnosed in 16 patients (20.0%). The position of the reconstructed metallic acetabulum was measured on an anteroposterior pelvic radiograph. Bone ingrowth was evaluated in 2 samples harvested from patients with tumor recurrence.
Results: After a median duration of follow-up of 32.5 months (range, 9 to 52 months), no acetabular component instability was detected on radiographs. Histological sectioning of specimens harvested from 2 patients with tumor recurrence showed bone trabeculae extending toward the implant and bone ingrowth within the porous network. At the time of the latest follow-up, 59 patients (73.8%) were alive with no evidence of disease, 5 patients (6.3%) were alive with disease, and 16 patients (20.0%) had died of disease. Local recurrence occurred in 9 patients (11.3%). The mean Musculoskeletal Tumor Society score at the time of the latest follow-up was 83.9% (range, 43% to 100%). Complications occurred in 16 patients (20%), with wound dehiscence being the most common complication (8 patients; 10%). No aseptic loosening was found. Five patients (6.3%) had deep infection, and 2 patients (2.5%) had dislocation.
Conclusions: The use of a 3-dimensional (3D)-printed modular hemipelvic endoprosthesis with a highly porous metal interface represents a potential choice as a pelvic endoprosthesis after internal hemipelvectomy for the treatment of a primary or metastatic tumor. These preliminary results demonstrate stable fixation with acceptable early functional and radiographic outcomes.
Level of evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.