Arthurs, Jennifer R.

Objective Bone marrow aspiration and concentration (BMAC) is becoming a more common regenerative therapy for musculoskeletal pathology. In our current pilot study, we studied patients with mild-to-moderate bilateral knee osteoarthritis, compared pain at 12-month follow-up between BMAC-injected and saline-injected knees, and examined cartilage appearance measured by magnetic resonance imaging (MRI) T2 quantitative mapping. Design Twenty-five patients with mild-to-moderate bilateral osteoarthritic knee pain were randomized to receive BMAC into one knee and saline placebo into the other. Bone marrow was aspirated from the iliac crests, concentrated in an automated centrifuge, combined with platelet-poor plasma for knee injection, and compared with saline injection into the contralateral knee. Primary outcome measures were T2 MRI cartilage mapping at 6-month and Visual Analog Scale and Osteoarthritis Research Society International Intermittent and Constant Osteoarthritis Pain scores and radiographs at 12-month follow-up. Results Constant, intermittent, and overall knee pain remained significantly decreased from baseline at 12-month follow-up (all P ⩽ 0.01), with no apparent difference between BMAC- and saline-treated knees (all P ⩾ 0.54). A similar significant increase from baseline to 12-month follow-up regarding quality of life was observed for both BMAC- and saline-treated knees (all P ⩽ 0.04). T2 quantitative MRI mapping showed no significant changes as a result of treatment. Conclusions BMAC is safe to perform and relieves pain from knee arthritis but showed no superiority to saline injection at 12-month follow-up. MRI cartilage sequences failed to show regenerative benefit with single BMAC injection. The mechanisms of action that led to pain relief remain unclear and warrant further studies.

Adipose-derived therapies have increased in popularity for treatment of painful orthopaedic conditions, such as osteoarthritis. We report the passage of fat into a Baker’s cyst after injection of micro-fragmented adipose tissue in a patient with bilateral knee arthritis. Following fat grafting, the patient required drainage of fatty fluid from within the Baker’s cyst on multiple occasions. Approximately 3 months postprocedure, she began to notice an improvement in her knee pain with no further recurrence of pain or swelling from her Baker’s cyst.