Modular arthroplasty in patients with primary malignant pelvic bone tumors of the periacetabular localization (clinical cases)

BACKGROUND: Treatment of patients with pelvic bone sarcomas is accompanied by a high percentage of complications and unsatisfactory treatment results. During reconstructive surgeries in patients with malignant tumors of the periacetabular localization, modular hip endoprotheses with a cup having a conical stem are increasingly used.

CLINICAL CASES DESCRIPTION: We analyzed 15 cases of periacetabular resections with acetabular reconstruction using the LUMiC modular endoprosthesis in patients aged 19 to 71 with pelvic bone lesions caused by primary malignant tumors. Distribution by gender, age, and nosology: there were 14 men (93.3%) and 1 woman (6.7%); the average age was 47.1 years; chondrosarcoma was diagnosed in 11 cases (73.3%), osteosarcoma in 3 (20%), and epithelioid hemangioendothelioma in 1 (6.7%). A combined approach was used in 10 patients, and an iliac-inguinal-femoral approach was used in 5 patients. Resections in the PI–II zone were performed in 2 patients, in the PII zone in 5 patients, in the PII–III zone in 6 patients, and in the PI–II–III zone in 2 patients. Complications occurred in 40.0% of cases during a median follow-up period of 37.2 months (6 to 64 months). The mortality rate was 6.7% (1 patient died in the early postoperative period due to acute myocardial infarction). Deep periprosthetic infection was detected in 3 patients (20.0%) at 3, 12 weeks, and 19 months, and the endoprostheses were removed: in 2 cases, nearthrosis was created, and in one case, an inter-iliac abdominal amputation was performed. Dislocation occurred in 1 case (6.7%) in the early postoperative period due to a violation of the orthopedic regimen and was resolved closed. 1 patient (6.7%) developed persistent sciatic neuropathy in the early postoperative period. No tumor progression was observed during the follow-up period. No cases of aseptic instability of the endoprostheses were observed. The functional result on the MSTS scale was good or excellent in 10 out of 15 cases, with an average of 69.7% (16,7% to 90%).

CONCLUSION: The use of modular hip endoprostheses, including a cup with a cone-shaped stem, during surgeries in patients with primary malignant tumors of the pelvic bones of the periacetabular localization, is a promising method of surgical treatment. However, according to our results and international data, the frequency of infectious complications (up to 25%) and dislocations (up to 19%) in the postoperative period remains relatively high, which requires further research.