Review Question - QID 219867

The patient is an elderly female with a proximal humerus fracture nonunion involving the surgical neck, making reverse total shoulder arthroplasty the most appropriate method of surgical treatment.

Proximal humerus fracture nonunions and malunions are not uncommon complications associated with proximal humerus fractures that can lead to persistent shoulder pain, instability, and restricted motion. The normal anatomy of the humeral head involves 30° of retroversion relative to the transepicondylar axis of the distal humerus, with a neck-shaft angle between 130° and 140°. The greater tuberosity position, which is essential for the proper anatomic function of the rotator cuff muscles, has a medial edge that is ~10mm lateral to the humeral canal axis and a superior edge that is ~6mm inferior to the top of the normal humeral head. When these parameters are affected by fracture malunion, they can be classified into subtypes using the system created by Boileau, with Type I injuries involving humeral head impaction and osteonecrosis, Type II injuries involving chronic fracture-dislocations, Type III injuries involving nonunion of the surgical neck, and Type IV injuries involving severe malunion of the tuberosities. According to this system of classification, Types I and II allow for the possibility of anatomic total arthroplasty use given theoretical preservation of the tuberosities, while Types III and IV either prevent normal tuberosity healing or lack adequate proximal bone stock for fixation and require treatment with a reverse total shoulder arthroplasty.

Boileau et al. retrospectively evaluated 203 patients with sequelae of proximal humeral fractures who were treated with a non-constrained modular and adaptable prosthesis (anatomic TSA) to assess the impact of a new radiographic classification on arthroplasty. The authors identified 137 impacted fractures with humeral head collapse or necrosis (Type 1 sequelae), 25 unreducible dislocations or fracture-dislocations (Type 2), 22 nonunions of the surgical neck (Type 3), and 19 severe tuberosity malunions (Type 4). They concluded that the results of non-constrained shoulder arthroplasty for the treatment of Type 1 and Type 2 sequelae were predictably good because no greater tuberosity osteotomy was performed, while patients with Type 3 or Type 4 sequelae had poor functional results with non-constrained arthroplasty because greater tuberosity osteotomy was needed.

Jobin et al. reviewed the use of reverse shoulder arthroplasty for the management of proximal humerus fractures. The authors note that the use of reverse shoulder arthroplasty is becoming increasingly popular for the treatment of complex three- and four-part proximal humerus fractures in the elderly compared with the often unpredictable and poor outcomes provided by open reduction and internal fixation and hemiarthroplasty. They conclude that satisfactory results can be obtained with careful preoperative planning and attention to technical details, with repair and union of the greater tuberosity fragment during reverse shoulder arthroplasty demonstrating improved external rotation, clinical outcomes, and patient satisfaction compared with outcomes after tuberosity resection, nonunion, or resorption.

Figures A and B represent AP and lateral scapular (y) radiographs of a right shoulder demonstrating chronic proximal humerus fracture nonunion with involvement of the surgical neck.

Incorrect Answers:
Answers 1 and 2: Given that this is a Boileau Type III injury, treatment with an anatomic total shoulder arthroplasty is unlikely to be successful, regardless of cement or stem use.
Answer 3: Hemiarthroplasty has been shown to have inferior results to total shoulder arthroplasty in the setting of fracture nonunion.
Answer 4: ORIF is unlikely to be successful in this setting given the chronicity of the fracture, the patient's bone quality, and the involvement of the surgical neck without adequate proximal bone stock for fixation.