Cell-Based Therapy by Autologous Bone Marrow-Derived Mononuclear Cells for Bone Augmentation of Plate-Stabilized Proximal Humeral Fractures: A Multicentric, Randomized, Open Phase IIa study

Proximal humerus fractures are common in an aging population. The standard operative treatment is open reduction internal fixation (ORIF) using an angular stable plate. However, this procedure has complications such as a relatively high rate of secondary dislocation, humeral head necrosis or nonunion caused by delayed bony consolidation. Autologous bone marrow mononuclear cells (BMC) combined with a β-TCP scaffold could support bone healing and is considered clinically safe. This multicentric, randomized, open phase IIa clinical trial (Clinical Trials. Gov Identifier: NCT02803177, Eudra CT No: 2015-001820-51) evaluated whether autologous BMC with β-TCP in addition to ORIF reduces the incidence of secondary dislocations in patients with proximal humerus fracture. Ninty-four patients equally divided between verum group (BMC+β-TCP) and control group (ß-TCP only) were targeted and calculated. At the time of planned interim evaluation, ie, enrolment of 56 patients, no statistical difference in secondary dislocations or complications was demonstrated in either group after an observation period of 12 weeks. Radiographic bone healing and DASH score to determine shoulder function were comparable between both groups. Bone marrow harvest and BMC transplantation did not result in any severe adverse events. Therefore, the study was terminated after the interim analysis, as no other result could be expected. From the study results, it can be concluded that the application of autologous BMC is well tolerated, and bone healing can be achieved. Augmentation of bone defects with β-TCP could be shown to be feasible and might be considered in other clinical situations.