Results of modular endoprosthetic reconstruction of periacetabular bone defects in patients with tumors of the acetabulum and hip joint

Introduction. Surgical treatment of patients with pelvic bone tumors, in particular periacetabular tumors, remains challenging. There are many different reconstruction options after resection of these tumors. These include allo- and autografts, megaprosthesis, saddle endoprosthesis, custom-made endoprosthesis, 3D printing endoprosthesis, and femur transposition with the formation of neo-arthrosis. However, all of them are characterized by technical complexity and high risk of postoperative complications. There is still no standard procedure for reconstruction after resection of malignant periacetabular tumors. To date, modular endoprosthesis is a well-established reconstructive device in orthopaedic oncology to manage wide bone resections. Modular systems provide patient-specific endoprostheses that could be modified during surgery. In this article, we present the results of modular acetabular endoprostheses in the treatment of patients with periacetabular tumors. Material and Methods. From 2011 to 2018, 30 patients underwent modular endoprosthetic reconstruction after periacetabular resection. There were 13 (43 %) male and 17 (57 %) female patients aged from 23 to 63 years (median age 45 years). Primary malignant bone tumors were detected in 19 (63 %) patients, giant cell tumor in 5 (17 %), local soft tissue sarcoma in 1 (3 %), solitary metastases of kidney cancer in 2 (7 %) and recurrent sarcoma after previous surgical treatment in 3 (10 %) patients. Results. The average duration of surgery was 310 minutes (range: 145-520 minutes), blood loss was 5520 ml (range: 600-20000 ml). The median follow-up time was 36 months. Histological examination revealed a positive resection margin in 3 (10 %) patients. At a follow-up from 6 to 40 months, disease progression was detected in 10 (33 %) patients. Eight (27 %) patients died on disease progression. Complications of various types were diagnosed in 11 (37 %) patients. Infectious complications were the most common (30 % of patients). The average value of the functional assessment by the MSTS scale was 59 % (15-82%). Conclusion. Modular endoprosthetic replacement for tumors of the acetabulum and hip joint is a promising surgical technique allowing adequate functional results to be achieved.