Chemotherapy May Obviate Prophylactic Femoral Nail Surgery for Multiple Myeloma Patients With High Mirels' Score Lesions and Impending Pathological Hip Fracture.

Bone involvement presents in >80% of patients with multiple myeloma. This causes lytic lesions for which prophylactic surgery is indicated to prevent pathological fractures if the lesion is graded ≥9/12 on Mirels' score. Although successful, these surgeries have risks and extended recovery periods. We present a case indicating myeloma chemotherapy may obviate prophylactic femoral nailing for high Mirels' score lesions in the femoral head with impending pathological hip fracture. A 72-year-old woman presented in December 2017 with back pain. A plain X-ray indicated degenerative anterolisthesis in her lumbosacral spine. Serum analysis revealed abnormal protein, globulin, alkaline phosphatase, and albumin levels while protein electrophoresis and serum immunofixation revealed raised immunoglobulin A (IgA) kappa paraprotein and kappa serum free light chains, respectively. Whole-body CT scans showed widespread lytic bone lesions and bone marrow biopsy confirmed infiltration by plasma cells. She was diagnosed with International Staging System (ISS) stage 3 multiple myeloma, which was successfully treated with bortezomib, thalidomide and dexamethasone with regular bisphosphonates that year. She presented again to the hospital in June 2020 with acute back and pelvic pain; Her paraprotein and serum-free light chains had increased significantly from her previous clinic appointment, indicating serological progression. MRI showed a relapse of the myeloma deposits in her right femoral head and spine. The deposit in her femoral head was graded 10/12 on Mirels' score, which indicated prophylactic femoral nailing. Instead, the patient was treated with daratumumab, bortezomib, and dexamethasone with escalation to monthly zoledronic acid infusions, as it was thought surgery would provide limited cytoreductive effect, preventing chemotherapy for six weeks post-surgery, potentiating pathological hip fracture and disease progression at other sites. This resulted in a complete response, thus reducing the deposits such that the femoral lesion was graded <8 on Mirels' score, improved her pain, and restored her ability to traverse stairs. She remains in complete response with ongoing daratumumab and denosumab maintenance treatment as of December 2022. Chemotherapy and bisphosphonates substantially reduced the myeloma deposit in the femoral head such that indications of prophylactic surgery were eliminated according to Mirels' score recommendations. This reduced the risk of pathological hip fracture whilst eliminating surgical complications. Further research should be conducted into the safety and efficacy of this treatment regimen in patients with high Mirels' score lesions. With this knowledge, consideration can be taken as to whether prophylactic femoral nailing is necessary given strong indications.