Minimum One-Year Follow up in Patients Undergoing Intra articular Autologous Bone Marrow Concentrate Injection for Osteoarthritic Knee Pain Therapy
Objective: Autologous Bone Marrow (ABMAC) is a promising alternative therapy to conventional treatments for knee osteoarthritis, with the potential to mitigate inflammation and improve joint function. The aim of the study was to determine the safety and therapeutic benefit at an average of twenty months (12-30) post procedure for the treatment of knee osteoarthritis with a single autologous bone marrow concentrate treatment combined with mechanical axis deviation accomplished through off-loading and a physical therapy protocol. Study participant-reported outcomes for Lower Extremity Functional Scale (LEFS), International Knee Documentation Committee (IKDC), Short-form 12 (SF12) and Visual Analog Scale for pain were assessed prior to the procedure and at specific time intervals during the treatment period.
Methods: 42 adult patients with an average age of 75 (57-90) with Kellgren-Lawrence grade II-III varus osteoarthritis of the knee were treated at a single site by a single investigator (SAYIII) in an open label pilot study with ABMAC. Each knee in each patient was treated with 6 mL bone marrow concentrate and 4 mL Nano-filtered growth factor concentrate combined with 2 mL autologous thrombin for activation of platelet dense granules.
Results: Patient reported outcomes data revealed 42 patients with an average follow up of 20 months after receiving a single intraarticular injection of autologous bone marrow concentrate. All patients had Kellgren-Lawrence stage 2-3 OA. No serious adverse events were reported with BMC harvest or injection in any patient. There were no infections. There was meaningful improvement in mean clinical outcome metrics from baseline in all patients during the period studied. At 12 months minimum with 20 months average, mean change in visual analog scale was from 5.8 to 2.3, representing an absolute change of 3.5, exceeding the published minimum clinically important difference of 2.5. The Lower Extremity Functional Scale score mean change was +17.6 from 56.3 to 73.9 exceeding a published 9 point minimum clinically important difference in scoring. The IKDC score mean change was +19.8 from 44 to 63.8 exceeding a published 8 point minimum clinically important difference. Differences from baseline to follow up in the SF-12 demonstrated improvement in both the physical component and the mental component. The physical component improved from 33.9 to 42.9 for a mean change of +9 exceeding the minimum clinically important difference of 3.77. The mental component of the SF-12 increased from 54.8 to 57.1 just falling short of the minimum clinically important difference of 3.29. Two patients had a recurrent effusion and pain at 3 months and were offered PRP augmentation that successfully relieved their clinical symptoms for the duration of the study.
Conclusion: Safety and efficacy for autologous bone marrow aspiration, concentration and intra-articular bone marrow injections for knee arthritis and catabolic knee pain syndrome provided relief for at least an average of 20 months (range 12-30) based on validated patient reported outcomes analysis. Further study is indicated to determine the longevity and endurance of the procedure in providing pain relief using a single intra-articular BMC injection in this patient subset. Additional study is needed to determine the best approach to the concentration and delivery of orthopaedic immunobiologics in this setting.