849 - Genicular nerve block in a patient with multiple myeloma with refractory knee pain: a case report

Case Diagnosis: A 74-year-old female with multiple myeloma (MM) presented with chronic knee pain secondary to her lytic lesion and refractory to multimodal pain management. She received a fluoroscopy-guided genicular nerve block (GNB) with local anesthetic and reported 50% pain relief and overall improvement in function.

Case Description: A 74-year-old female presented with chronic left knee pain. Initial XR showed scattered lytic lesions throughout the femur, tibia, and fibula, with skeletal survey noting osteopenia and MRI showing marrow infiltration. She was diagnosed with MM and received chemotherapy with complete remission. She continued to have knee pain and failed multimodal pain management including PT as well as oral and topical pain medications. Corticosteroid injection was deferred due to risk of worsening her localized lytic lesion and osteopenia. She then received a left GNB with 0.75% bupivacaine. Pre-procedure pain score was 10/10 and immediate post-procedure pain score was 0/10. At six weeks post-procedure, she endorsed 50% relief of pain with only mild interference with ADLs via the Brief Pain Inventory.

Discussions: Up to 90% of MM patients have osteolytic bone lesions due to dysregulation in bone remodeling, leading to increased bone destruction, impaired formation, and reduced bone density. These patients frequently experience chronic pain, mobility impairments, depression, insomnia, and reduced quality of life. Management requires a multidisciplinary approach, including analgesics, antimyeloma treatment, radiotherapy, and/or surgery. While steroid injections are often used for joint pain, these should be avoided in MM patients due to the risk of adversely affecting bone mineral density. Though GNBs have primarily been used for chronic knee osteoarthritis, they are a reasonable modality for knee pain related to MM.

Conclusions: Genicular nerve blocks could be a potential intervention to manage chronic knee pain secondary to lytic lesions from MM, as they can help patients improve function and overall quality of life.