summary Humeral Shaft Nonunion is characterized by the arrest of the fracture repair process of a humeral shaft fracture which may occur following nonoperative or operative management. Diagnosis can be made with plain radiographs. CT studies are helpful to assess the extent of bridging callous and for preoperative planning. Treatment is generally open reduction with compression plating with or without bone grafting. Epidemiology Incidence of primary nonunion 2 to 33% with nonoperative management 5 to 10% with surgical management Anatomic location proximal third humeral shaft fractures are felt to have higher rates of nonunion Risk factors biologic metabolic/endocrine abnormalities (osteoporosis, Vitamin D deficiency most common) infection patient factors (smoking, obesity, malnutrition, noncompliance) open fracture mechanical unstable fracture patterns with inadequate stability shoulder or elbow stiffness (motion directed to fracture site) Etiology Pathophysiology pathophysiology inadequate stability at fracture site with operative or nonoperative treatment pathobiology inadequate biology as a result of metabolic/endocrine abnormalities, infection, smaller bone surface area for healing Associated conditions radial nerve palsy Anatomy Blood Supply nutrient vessel of humerus courses along the medial aspect of the mid to distal third of the diaphysis Muscles pectoralis major and deltoid create strong deforming forces on proximal diaphyseal fractures Tendon biceps tendon interposition in proximal diaphyseal fractures may lead nonunion Presentation Symptoms pain with use of the extremity Physical exam inspection assess the fit of functional brace and skin irritation atrophy angulation motion gross motion at the fracture site neurovascular assess radial nerve function Imaging Radiographs recommended views AP and lateral of the humerus, shoulder, and elbow findings lack of fracture consolidation hypertrophic callous formation pseudarthrosis CT indications to evaluate for the extent of bridging callous and preoperative planning Studies Serum Labs CRP, ESR, CBC must rule out infection total protein and serum albumin vitamin D, TSH, PTH Treatment Nonoperative functional bracing +/- bone stimulation indications login to view 1 more bullet modalities login to view 4 more bullets Operative compression plating with bone grafting (gold standard) indications login to view 1 more bullet outcomes login to view 1 more bullet dual plating indications login to view 3 more bullets outcomes login to view 1 more bullet cortical strut allograft/autograft indications login to view 3 more bullets outcomes login to view 1 more bullet bone morphogenic proteins (BMP's) indications login to view 1 more bullet Techniques Compression plating with or without bone grafting approach anterior anterolateral posterior login to view 1 more bullet soft tissue radial nerve protection and neurolysis bone work debridement of fibrous tissue and bone ends to stimulate healing fracture reduction with maximal cortical contact and stability autologous bone grafting from ICBG if atrophic nonunion DBM, RIA, or local callous autograft as alternative grafts instrumentation 4.5mm compression plate placed anterior, lateral, or posterior complications specific to this treatment radial nerve neuropraxia or injury ICBG donor site morbidity outcomes nearly 100% union rate reported 44% rate of ICBG donor site morbidity Dual plating instrumentation place additional plate orthogonal to the first plate Cortical strut allograft/autograft bone work place strut intramedullary and then place the plate place strut medially and place laterally based compression plate Complications Nerve injury radial nerve most common Persistent nonunion treatment free fibular grafting login to view 2 more bullets Prognosis With operative treatment of nonunion, 83-100% of patients go on to union