Bone healing of distal radius nonunion treated with bridge plating with bone graft substitutes in combination with systemic romosozumab administration: A case report

Abstract

Romosozumab is a humanized, anti-sclerostin monoclonal antibodyused to treat osteoporosis, which increases bone formation anddecreases bone resorption. It enhances fracture healing and systemicromosozumab administration may have therapeutic potentials foraccelerating bone healing of even nonunion. Herein, a 61-year-oldheavy smoker male with distal radius nonunion who achievedsuccessful bone union by combination therapy of romosozumaband spanning distraction plate fixation with bone graft substituteswas presented. Through the dorsal approach, atrophic comminutednonunion of the distal radius was sufficiently debrided. Reductionof the distal radius was performed using indirect ligamentotaxis,and a 14-hole locking plate was fixed from the third metacarpalto the radial shaft. A beta (β) tricalcium phosphate block wasmainly packed into the substantial metaphyseal bone defect withadditional bone graft from the resected ulnar head. Postoperatively,systemic administration of monthly romosozumab was continuedfor six months. Complete bone union was achieved 20 weekspostoperatively and the plate was, then, removed. Wrist extensionand flexion improved to 75º and 55º, respectively, without pain, andgrip strength increased 52 weeks postoperatively from 5.5 kg to22.4 kg. During romosozumab treatment, bone formation markerlevels increased rapidly and finally returned to baseline, and boneresorption marker levels remained low. In conclusion, combinationof systemic romosozumab administration and grafting β-tricalciumphosphate with bridge plating provides an effective treatmentoption for difficult cases of comminuted distal radius nonunionwith risk factors such as smoking, diabetes, and fragility.