Cementless Long-Stem Reverse Total Shoulder Arthroplasty as Primary Treatment for Metadiaphyseal Humeral Shaft Fractures.

Background: The use of cementless diaphysis-fitting stems has been shown to be an effective treatment option for cases of metadiaphyseal humeral fracture. Complex metadiaphyseal fractures are those that extend below the surgical neck into the diaphysis, which can compromise the metaphyseal fixation of typical arthroplasty designs. The presently described surgical technique circumvents the potential risks associated with the use of cement while also permitting the treatment of common concomitant pathologies, such as arthritis and rotator cuff tendinopathy. Evidence supports the efficacy of this technique, showcasing consistent rates of healing, pain relief, and functional recovery, as well as acceptable complication rates compared with alternative surgical options.

Description: The surgical procedure is performed with the patient in a modified beach chair position. A deltopectoral approach is utilized in order to expose the humerus and glenoid. In cases in which the tuberosity is fractured, it is carefully tagged for subsequent repair. The metadiaphyseal extension of the fracture is exposed, and reduction is performed with cerclage cable augmentation as needed. When direct reduction proves challenging, the humeral prosthesis is utilized to aid in reduction. Full-length humeral radiographs and a humeral sounder are utilized to guide the placement of a trial prosthesis, ensuring that the stem spans 2 canal diameters past the fracture and restores the appropriate humeral length. The medullary stem is utilized as support for fracture fragment reduction, with use of a combination of bone stitching and cerclage cables as required. Fractures with compromised proximal humeral bone stock can be further augmented with extramedullary strut allografts and cerclage cables. The allograft strut fixation acts as a neutralization plate to maintain rotational control. The joint is reduced, and fixation of the subscapularis and tuberosity is achieved with use of a transosseous suture technique. This technique combines the use of arthroplasty as well as standard osteosynthesis principles to treat complex metadiaphyseal humerus fractures.

Alternatives: Nonoperative treatment may be indicated in a primary setting and represents a multifactorial patient-specific decision. Other surgical options include open reduction with internal fixation with plates or an intramedullary humeral nail, and cemented long-stem arthroplasty. If the fracture is too distal and the surgeon is unable to achieve a length of 2 canal diameters for distal fixation, alternative treatment strategies such as cementation may be required.

Rationale: This procedure is most often performed in elderly patients with osteoporosis, who often also have comminuted fracture patterns and conditions such as glenohumeral arthritis or chronic rotator cuff pathology^1,5,6,13,15. Whereas open reduction and internal fixation (ORIF) can be effective in younger patients, it poses higher risks of complications in patients with osteoporosis^1,3,9,14-16. Neither ORIF nor intramedullary nailing addresses concurrent pathologies. Another alternative technique involves the use of a cemented stem; however, a cementless approach eliminates theoretical risks of cement use, allows easier revisions, and achieves comparable outcomes^9,16,20. In summary, cementless long-stem RTSA offers consistent healing rates, satisfactory outcomes, and favorable results.

Expected outcomes: Cementless long-stem reverse total shoulder arthroplasty (RTSA) is a viable alternative for elderly patients with metadiaphyseal proximal humeral fractures. This technique shows consistent healing rates, pain relief, shoulder function restoration, and an acceptable complication rate. In a study of 14 patients who underwent cementless long-stem RTSA from September 2017 to August 2020, all patients showed improved outcomes and radiographic evidence of union at an average of 13 months postoperatively. Minor complications have been reported, such as transient neuropathy, tuberosity nonunion, and humeral stress shielding.

Important tips: This technique is optimal for elderly patients with osteoporotic bone, comminuted fractures, glenohumeral arthritis, and/or rotator cuff pathology.Long comminuted fractures require bridging fixation, spanning 2 canal diameters beyond the fracture site.Patients with compromised proximal humeral bone stock may require allograft strut augmentation.The surgical principle integrates standard arthroplasty for joint length restoration, a relative fracture stability concept by spanning complex fracture segments, and an absolute stability concept by direct fragment alignment.

Acronyms and abbreviations: RTSA = reverse total shoulder arthroplastyIMN = intramedullary nailORIF = open reduction and internal fixationAVN = avascular necrosisAP = anteroposteriorCT = computed topographyTSA = total shoulder arthroplastyXR = plain radiographsFU = follow-upSST = simple shoulder testASES = American Shoulder and Elbow SurgeonsDASH = Disabilities of the Arm, Shoulder and HandPROM = patient-reported outcome measuresROM = range of motion.