Background
Malignancies involving the pelvic ring present numerous challenges, especially in the periacetabular area. Extensive resection of the pelvic region without reconstruction can lead to severe functional impairment. Numerous reconstructive options exist, but all have drawbacks. Extracorporeally irradiated autografts are one option for reconstruction after periacetabular resections; they offer the potential advantages of eliminating the risk of allogeneic reactions associated with allografts and preserving local anatomy. However, little is known about the durability and risks of this approach in pelvic reconstruction.
Questions/purposes
(1) What are the survival rates of the autograft used, and if there is graft loss, what is the extent of this loss? (2) What are the functional outcomes after the implementation of this method? (3) What is the rate and nature of complications associated with this approach?
Methods
This is a retrospective case series from one subspecialty tumor unit that evaluated patients treated between January 2005 to January 2022. During that time, three surgeons treated 48 patients with Type II resections (defined as resection of periacetabular area). Patients treated with isolated Type II resections were eligible, as were those treated either with Type I+II resections, Type II+III resections, Type I+II+III resections, and Type I+II+III+IV resections. Of those, 21% (10 of 48) were treated primarily with a cone prosthesis, 13% (6 of 48) were treated without femoral reconstruction, 10% (5 of 48) were treated with resection without reconstruction, and 6% (3 of 48) had a THA on the sacrum, leaving 50% (24 of 48) of patients who were treated with femoral and acetabular reconstruction using extracorporeally irradiated autograft and total hip replacement; those patients were potentially eligible for this study. During that time span, we used this approach in all Type II pelvic resection procedures, when a part of the hemipelvis could be preserved without resection (other than Type I+II+III+IV) and where we predicted that there would be sufficient bone stock after tumor removal. Of those, 21% (5 of 24) were lost to follow-up before 2 years, and 13% (3 of 24) died within 2 years with the reconstruction intact and without any reoperation or graft loss, leaving 67% (16 of 24) for analysis here. Demographic characteristics, type of tumor, tumor origin site, type of applied resection, and extent of applied surgical procedure were noted. Of 16 patients, 12 were male, with a mean age of 38 ± 21 years. Tumor types included chondrosarcoma in eight patients, malignant mesenchymal tumor in four patients, osteosarcoma in two patients, and Ewing sarcoma in two patients. Among these, 10 patients had tumors originating from the pelvis, whereas six patients had tumors originating from the proximal femur. We used a Kaplan-Meier estimator to calculate survivorship free from total or partial graft removal at 72 months. To measure functional results, the Musculoskeletal Tumor Society (MSTS) scoring system was utilized at most recent follow-up so as to be able to evaluate the impact of complications (if any) on the ultimate result. The MSTS score ranges from a minimum of 0 points to a maximum of 30 points, where a higher score reflects lower pain and higher functional and emotional capacity. Related complications, time of complications, secondary interventions, and mortality rates were also ascertained from chart review.
Results
Graft survival rate at 72 months after initial reconstruction, free from partial or total graft removal, was 50% (95% CI 26% to 75%). Kaplan-Meier analyses revealed estimated mean time of graft removal as 43 months (95% CI 28 to 58). The graft was protected in eight patients on their final follow-up radiographs. The median (range) MSTS score was 18 (6 to 25) of 30 points at most-recent follow-up (these scores include patients who have had their grafts removed). In all, 15 of 16 patients had 17 complications; 16 were major complications (defined as those substantial enough to result in further surgery or a life- or limb-threatening event). A total of 14 of those 15 patients underwent one or more secondary procedures (a total of 21 unplanned additional procedures were performed in those patients). Deep infection was the most common complication, occurring in eight patients. Prosthesis dislocation occurred in four patients. Three patients developed aseptic acetabular component loosening, two had graft fractures, and one patient developed heterotopic ossification.
Conclusion
Composite reconstruction with extracorporeal irradiated autografts plus total hip replacement is a feasible reconstruction technique after Type II pelvic resections, although complications and reoperations were common. Although no reconstruction technique has been proven superior to other alternatives, the high risk of complications and reoperations associated with this technique should be considered when selecting from among possible alternative reconstruction methods.
Level of Evidence
Level IV, therapeutic study.
