Intraosseous Bone Marrow Concentrate and Long-Term Procedure-Free Survival in Bilateral Non-Traumatic Ankle...

Background and Objectives: Joint-preserving options for bilateral non-traumatic ankle osteoarthritis (OA) are limited. This study evaluated whether intraosseous bone marrow concentrate (IO BMC) was associated with a lower observed occurrence of ankle arthrodesis or total ankle arthroplasty and greater procedure-free survival, and whether delivered colony-forming unit-fibroblast (CFU-F) count was associated with procedure-free survival. Materials and Methods: This retrospective, non-randomized, contralateral-controlled study included 88 patients with bilateral non-traumatic ankle OA treated between 2000 and 2014. The more symptomatic ankle received IO BMC, whereas the contralateral ankle was managed non-operatively. The primary endpoint was subsequent ankle arthrodesis or total ankle arthroplasty. Survival analyses were truncated at 15 years. Results: Arthrodesis or arthroplasty occurred in 16 of 88 IO BMC-treated ankles (18.2%) and 44 of 88 control ankles (50.0%). Thirty patients underwent a procedure only on the control side compared with two only on the IO BMC-treated side (p < 0.001). In the adjusted Cox model, IO BMC treatment was associated with a lower hazard over 15 years (summary HR = 0.24, 95% CI 0.15 to 0.38, p < 0.001), representing a summary association over the analysis interval rather than a constant effect. Restricted mean procedure-free survival was 9.89 versus 8.10 years through ten years (difference 1.78 years, 95% CI 1.28 to 2.32) and 14.23 versus 10.77 years through 15 years (difference 3.46 years, 95% CI 2.58 to 4.40). In an exploratory analysis with only 16 endpoint events, higher delivered CFU-F count remained associated with greater procedure-free survival (HR = 0.70 per 10,000-cell increase, 95% CI 0.55 to 0.90, p = 0.004). Conclusions: IO BMC treatment was associated with a lower observed occurrence of arthrodesis or arthroplasty and greater procedure-free survival in bilateral non-traumatic ankle OA. Higher delivered CFU-F counts were also associated with greater procedure-free survival in an exploratory analysis. These observational findings do not establish a causal treatment effect.