Unique case report of shoulder girdle fracture following reverse shoulder arthroplasty: a 1-year follow-up

Reverse total shoulder arthroplasty (rTSA) is increasingly utilized to address complex shoulder conditions in elderly patients, including those with chronic glenohumeral dislocations. rTSA may provide superior outcomes compared to humeral arthroplasty or anatomic total shoulder arthroplasty. rTSA offers a biomechanical advantage by medializing and distalizing the center of rotation, thus optimizing deltoid leverage in patients with rotator cuff insufficiency. Although rTSA typically outcomes are generally favorable, complications such as infections, scapular spine fractures, and instability can arise. We present a unique case of an 88-year-old female patient who experienced sequential fractures around the shoulder girdle following rTSA. This case highlights the complexity of managing post-operative complications in elderly patients with high functional demands. It also illustrates the potential of conservative treatment strategies in achieving functional recovery despite radiographic imperfections.

Chronic anteroinferior glenohumeral joint dislocation is rare in elderly patients but can be effectively addressed with rTSA, especially in high-demand cases.^7,15 Its management is challenging due to associated rotator cuff tears, joint degeneration, and poor bone quality. rTSA is widely recognized for its ability to restore shoulder function; however, it is not without complications, including infections, scapular fractures, and prosthetic instability.3, 4, 5^,12,16 This case report details an atypical presentation of sequential shoulder fractures following rTSA, underscoring the need for vigilant follow-up and management and the biomechanical importance of the superior shoulder suspensory complex. The integrity of this complex is increasingly recognized as a key factor in post-operative shoulder stability and load transfer.

Case presentation

An 88-year-old, right-hand–dominant female patient presented with a chronic anteroinferior shoulder dislocation that was later accompanied by a fracture of the coracoid process (Figs. 1 and 2). She underwent a successful rTSA (Fig. 3) (SMR Prosthesis; Enovis, Wilmington, DE, USA) through the deltopectoral approach, which was planned pre-operatively with a three-dimensional computed tomography scan using the Materialise surgical protocol (Materialise, Leuven, Belgium) (Fig. 4). This allowed precise assessment of glenoid version, inclination, and bone stock, which informed the decision for augmented baseplate positioning. Due to the increased superior inclination, a superior 15° augmented baseplate (SMR TT 360 metal-backed augmented 15°; Enovis, Wilmington, DE, USA) was utilized to correct the rTSA angle.² The initial postoperative course was uneventful (Fig. 5).

Figure 1.

Preoperative CT scan performed in December 2023. (A) Axial view demonstrating mild anterior subluxation of the shoulder. (B) Sagittal plane showing an intact coracoid process. CT, computed tomography.

Figure 2.

Preoperative imaging of the shoulder. (A) Three-dimensional CT scan demonstrating a fractured coracoid process. (B) Neer-view radiograph showing subluxation of the humeral head with an associated coracoid process fracture. (C) Axial imaging view demonstrating humeral head subluxation and fracture of the coracoid process. CT, computed tomography.

Figure 3.

Immediate post-operative AP and Neer-view radiographs following reverse total shoulder arthroplasty. AP, anteroposterior.

Figure 4.

Preoperative surgical planning demonstrating a superior glenoid inclination of 15°. P, posterior; S, superior.

Figure 5.

Radiographs obtained six weeks postoperatively following reverse total shoulder arthroplasty.

Five months after surgery, she presented with pain and limited shoulder mobility. Three-dimensional computed tomography scans of the shoulder confirmed the radiographic diagnoses and showed the displaced location of the scapular spine fracture, Levy type III, with an additional undisplaced fracture line heading toward the fossa supraspinata (Fig. 6). After extensive discussion of conservative vs. operative treatment options, the fractures were managed conservatively using an abduction brace for six weeks (Okin shoulder brace, 15° external rotation; OKIN AG, Sarnen, Switzerland).

Figure 6.

(A) Axial CT scan demonstrating a scapular spine fracture, Levy type III. (B) Radiograph obtained six weeks after diagnosis of the scapular spine fracture. CT, computed tomography.

Several weeks later, the fracture healed uneventfully in a slightly dislocated position. The range of motion (ROM) was limited, but she was still able to use her arm for daily activities. Three months later, she returned with an acute displaced clavicle fracture (Fig. 7). Conservative management was again elected, using a sling for an additional six weeks, given the patient's age, functional status, and preferences (Fig. 7).

Figure 7.

(A) Midshaft clavicle fracture diagnosed eight months after surgical treatment. (B and C) Radiographs obtained six weeks after conservative management of the clavicle fracture, demonstrating early callus formation.

This decision resulted in satisfactory healing and maintenance of shoulder function with some movement restrictions (Fig. 8). Despite radiological malalignment, the patient regained sufficient ROM to perform essential activities of daily living independently. Post-operative shoulder ROM at 1 year after surgery is demonstrated in Supplementary Figure S1.

Figure 8.

(A) One-year post-operative AP radiograph of the shoulder. (B) One-year postoperative Y-view radiograph of the shoulder. (C) One-year postoperative AP radiograph of the clavicle demonstrating complete callus formation. AP, anteroposterior.

Discussion

Anterior shoulder dislocations lead to substantial structural damage and significant functional impairment. It is well recognized that the duration of the dislocation poses a significant risk for complications. Chronic anterior dislocation in the elderly can be treated successfully with reverse shoulder arthroplasty.^7,15

The incidence of scapula spine fractures (SSFs) varies in the literature from 2.8% to 15%.^4,11 This variability highlights the multifactorial etiology of such fractures, including implant design, patient-specific bone quality, and post-operative loading conditions. The patient's advanced age, osteoporotic bone quality, and potential alterations in biomechanical loading after arthroplasty may have contributed to her susceptibility to fractures.^4,12,10,11 The occurrence of post-operative fractures around the shoulder girdle after rTSA is uncommon but not unheard of. The exact cause of SSFs remains uncertain. It is assumed that altered force transmission through the deltoid muscle, in combination with distalization and lateralization effects of certain prosthetic designs, plays a critical role in stress distribution across the scapular spine. Denard et al⁶ reported that an onlay design resulted in a 10-mm increase in distalization compared to an inlay stem, along with a 2.5-fold increased risk of SSF. Moreover, lateralization on the glenoid side of up to 8 mm does not appear to increase SSF risk.¹³ There is still no consensus on how to manage these types of fractures. Schenk et al¹⁴ showed that operative treatment was not superior to conservative therapy for Constant Score, Subjective Shoulder Value, or ROM.

However, just recently, Bauer et al¹ showed that acute displaced Levy type II or III fractures are associated with significantly better clinical outcomes and union rates compared to nonoperative management. Type II fractures involve the acromial base and type III extend to the scapular spine, often compromising deltoid function and fixation options. Several biomechanical papers showed favorable outcomes with double-plate osteosynthesis.^8,9 The biomechanical background for the occurrence of these fractures remains unclear. However, the perioperative fracture of the superior shoulder suspensory complex may give a better understanding of the origin of these. Surgeons should be aware of perioperative stress risers in this region and consider them during pre-operative planning, especially in osteoporotic bone. Further biomechanical studies were necessary to elucidate these mechanisms.

Conservative management of such fractures around the shoulder girdle is a plausible approach and can lead to satisfactory outcomes, as demonstrated in this case. Currently, this may be the only documented instance of sequential multiple fractures around the shoulder girdle post-rTSA in the literature.

Conclusion

This case highlights the importance of individualized management strategies following rTSA, particularly in the elderly population, who are at elevated risk of fractures due to altered biomechanics and compromised bone health. Even in advanced age, high functional demands may necessitate a more nuanced approach to rehabilitation and risk monitoring. Timely and regular follow-up is essential in identifying and addressing complications early.

Further studies may help to better identify risk factors and to deepen our understanding of these fracture types. This case further suggests that, under carefully monitored conditions, conservative treatment may be a valid alternative to surgical fixation in selected patients with stable fracture configurations.

Future research should focus on integrating patient-specific biomechanical simulations into pre-operative planning. Finite element models may help identify stress-prone areas and guide implant selection and alignment strategies in vulnerable populations.

Disclaimers

Funding: The authors declare that no funds, grants, or other support were received for this study.

Conflicts of interest: The authors, their immediate families, and any research foundation with which they are affiliated did not receive any financial payments or other benefits from any commercial entity related to the subject of this article declare that they have no conflict of interest.

Patient consent: Obtained.