(P 279) CEMENT AUGMENTATION WITH CEPHALLOMEDUALLARY FIXATION OF PRIMARY AND METASTATIC LESIONS OF THE PROXIMAL FEMUR.

Objective: Cement augmentation for the prophylactic and therapeutic fixation of osseous metastatic lesions has demonstrated promising clinical outcomes in the context of percutaneous sacroiliac fixation, cannulated femoral neck screws, and intramedullary nailing for diaphyseal lesions. While cement augmented cephallomedullary nailing systems have been associated with fewer complications, shorter hospital stays, and less reoperations in elderly individuals with osteoporosis, this construct has not been studied in patients with primary or metastatic lesions of the proximal femur. The objective of this case series was to determine the clinical efficacy and safety of using a cephallomeduallary nailing system with a fenestrated lag screw for cement augmentation of primary and metastatic lesions of the femoral neck and head.

Methods: This study included patients undergoing cephallomedullary nailing with cement augmentation for therapeutic treatment of metastatic or benign primary lesions of the femoral neck and head by two surgeons with fellowship training in Orthopaedic Oncology. Surgeries were performed at a single academic institution from August 2021 to June 2022. Cephallomedullary nailing was performed in standard fashion, with fenestrated lag screw placement into the femoral head. Following the desired position of the lag screw, 15 milliliters of iohexol was injected through the screw to confirm that there was no extravasation into the joint or through any fractures or lesions. Cement was then injected through the screw in multiple trajectories based on the position of the lesion relative to the screw, allowing excellent fill of any tumor cavities. To determine clinical safety and efficacy of this technique, 30-day post-operative complications (infection, hardware failure, re-fracture, re-operation, wound complications, pulmonary embolism, deep venous thrombosis (DVT)) readmissions, subjective pain, and ambulatory statuses were obtained from the electronic medical record.

Results: A total of 10 patients underwent surgery with the described technique during the time of this ongoing study. There were seven females and three males, with an average age of 60 at time of surgery. Seven patients underwent prophylactic nailing for metastatic breast cancer and multiple myeloma, and three patients underwent fixation for pathological fractures. The diagnoses included multiple myeloma, hepatocellular carcinoma (2), prostate carcinoma (2), breast carcinoma (2), lung carcinoma, polyostotic fibrous dysplasia, and poorly differentiated carcinoma presumed to have metastasized from the liver. There were no immediate operative complications, infections, or re-operations. One patient was diagnosed with a DVT and pulmonary embolism 4 days after surgery and was successfully managed medically. There were no other complications or hospital readmissions related to surgery with a mean follow-up of 116.4 days. One patient died of disease 5 months after the operation. Subjective pain after at least 30 days was improved in all patients. After at last follow up 7 patients were weight bearing without assistive devices, and 2 patients were weight bearing with the use of a walker or cane. One patient remained non-ambulatory as she had been non-ambulatory for 6 months prior to her fracture, which occurred during a transfer for hygiene.

Conclusion: Our case series suggests early safety and efficacy of a novel technique for addressing impending and sustained pathological fractures of the femoral neck and head. Multidirectional cement augmentation via a fenestrated lag screw as a part of a cephallomedullary nail construct was effective in filling both metastatic and primary lesions of the femoral neck and head, with the goal of improved mechanical stabilization. One patient sustained a venous thromboembolism and there were no surgery related complications, reoperations, or readmissions related to surgery. These results suggest treatment in-line with the palliative goals of Orthopaedic Oncology in the context of metastatic bone disease, demonstrated by 30-day ambulatory status and subjective pain reports. Potential advantages of this technique over larger open procedures traditionally used to treat lesions of the femoral head and neck, such as hip arthroplasty, may include decreased blood loss, complications, operative time, recovery, and the ability to continue systemic treatment. Importantly, we do not suggest that all lesions of the femoral head and neck might be treated with this technique, but for select lesions in select patients this may prove to be an alternative surgical option. Limitations of our study include population heterogeneity regarding patient factors and histology, short-term follow-up, non-randomization, and small sample. These early results are encouraging and will continue to yield data over to improve assessment of outcomes and allow for more granular analyses, but at its current stage this case series suggests promising palliation in the use of this novel technique.