Anatomic total shoulder arthroplasty in patients under 50 and over 80 years of age. Part 2

Anatomic total shoulder arthroplasty is a widely used definitive surgical solution for end-stage glenohumeral joint osteoarthritis and is associated with good clinical outcomes. Anatomic total shoulder arthroplasty has a role for patients under 50 years of age who have exhausted nonoperative management and for patients over 80 years of age with an intact rotator cuff. Patients younger than 50 place greater demands on their replaced shoulders, raising concerns about implant survivorship and in particular the failure of the glenoid component. There are limited data on the long-term survivorship of anatomic total shoulder arthroplasty in patients under the age of 50 years in the literature. Modern bone-preserving designs utilizing newer materials may contribute to improved outcomes and survivorship. Achieving comparable functional outcomes in patients over 80 years of age remains a challenge with concerns related to rotator cuff failure. However, in appropriately selected patients over the age of 80 years, an anatomic total shoulder arthroplasty provides better pain relief and function than a reverse total shoulder arthroplasty.

As life expectancy increases, a large number of older but active patients will suffer from shoulder arthritis with debilitating pain and functional loss that may threaten their independence. Ricchetti et al. demonstrated that total shoulder arthroplasty (TSA) can be performed on patients 80 years and older, and reported rates of perioperative complications and mortality comparable to those of younger patients [1]. However, there is a limited amount of literature on the outcome of anatomic total shoulder arthroplasty (aTSA) in older patients [2][3][4].

Indications for aTSA in older patients
Anatomic TSA is the definitive surgical solution for patients with primary glenohumeral joint osteoarthritis with an intact and functioning rotator cuff [4,5]. Recently, there has been a shift, with some surgeons performing reverse TSA (rTSA) for all older patients despite the underlying pathology-even for patients who clearly meet the indications for aTSA [6,7]. This is due to the fear of failure of the aTSA secondary to rotator cuff failure requiring revision to rTSA [8].
One of the major complications of aTSA failure is late rotator cuff failure [9]. Young et al. [10] reported a secondary rotator cuff dysfunction rate of 17% following aTSA and this was related to poorer clinical outcomes. As rotator cuff quality deteriorates Obere Extremität 1 · 2023 37 with advancing age [11], there is additional concern about rotator cuff resilience and long-term outcomes of aTSA in patients over the age of 80 years. Foruria et al. [4] reported outcomes of aTSA in 50 shoulders of patients over the age of 80, with a mean follow-up of 5.5 years. Four shoulders had a preoperative full-thickness rotator cuff tear. The authors found a radiological upper migration of the humeral head in five shoulders and suggested that the high frequency may have been related to deficiency of the rotator cuff. However, excellent results can be expected when aTSA is performed on patients over the age of 80 with a preoperative intact rotator cuff [8].
Thus, increasing age should not be a contraindication in itself for the aTSA. A careful clinical examination of the range of motion (ROM) and a thorough rotator cuff examination are essential. Preoperative ROM has been shown to be a good predictor of postoperative outcomes after aTSA [12]. If there are any doubts about the clinical examination of the rotator cuff, preoperative magnetic resonance imaging (MRI) is recommended. An MRI examination will enable a detailed assessment of the rotator cuff including the presence of partial and/or full-thickness tears, muscle atrophy, or the presence of any fatty infiltration. It has been demonstrated that preoperative fatty infiltration of the infraspinatus muscle and superior inclination are negative prognostic factors for aTSA [10]. Chronic irreparable subscapularis deficiency is a contraindication as it tends to destabilize the joint secondary to an upward migration of the humeral head and eccentric contact pressure onto the glenoid [13]. Assessment of the critical shoulder angle (CSA) on plain radiographs is also useful. A CSA < 30°is strongly associated with glenohumeral joint arthritis [14]. A CSA > 35°is related to an increased supraspinatus loading to compensate for increased joint instability, and in the setting of aTSA it is related to an increased incidence of glenoid radiolucencies [15]. Furthermore, the acromiohumeral distance (AHD) should be maintained (7 mm), indicating that the glenohumeral joint is centered with an intact and functioning posterior-superior rotator cuff.
The surgical indications for rTSA have expanded to include primary glenohumeral joint osteoarthritis with the presence of a functioning rotator cuff. Some centers have reported that more than 50% of their primary shoulder arthroplasties are now performed using rTSA [16], and this percentage is even higher for older patients. However, the choice of an rTSA over aTSA is associated with some unique and challenging complications not seen after aTSA, such as acromial stress/scapular spine fractures [17], inferior glenoid notching [18,19], and a higher rate of deep infection [20]. Additionally, function and ROM after rTSA are not comparable to aTSA, especially restoration of internal rotation.
Thus, despite the recent increase in the use of rTSA in older individuals with primary glenohumeral joint arthritis, aTSA provides better function and has a less challenging complication profile [21]. Moreover, patients undergoing aTSA have a faster recovery and achieve clinical improvement quicker than those undergoing rTSA [22]. Older patients with primary glenohumeral joint osteoarthritis with an intact rotator cuff, CSA < 30°, and a normal AHD meet the indications for an aTSA procedure with satisfactory and predictable clinical outcomes and longevity. When discussing shoulder arthroplasty as a definitive surgical solution in older patients with primary glenohumeral joint osteoarthritis with an intact rotator cuff, the treating surgeon should discuss both aTSA and rTSA. The patients should be informed of the risks, benefits, expectations, complications, and postoperative rehabilitation in detail, so that they can make a fully informed choice between aTSA and a rTSA-since the literature supports the use of aTSA for older adults [23].

Outcomes of TSA in older patients
Although the incidence of TSA in older patients has increased in recent decades [24], very few studies have reported outcomes of aTSA in patients over 80 years of age.
Foruria et al. [4] reported outcomes of aTSA for primary osteoarthritis in 50 shoulders of patients over the age of 80 to re-view its safety, efficacy, and complication rate. Although there was a requirement for more intense patient care in the perioperative period, the authors concluded that aTSA was effective in reducing pain and improving movement without increased risk of medical or surgical complications. Most of these patients had a pain-free and functional shoulder for the rest of their lives. Similar findings were reported by Ricchetti et al. [1] in a group of 40 patients over 80 years of age, with a comparable rate of perioperative complications to the younger patient group. The authors did, however, note that these older patients had an increased transfusion requirement and there were fewer cases of direct discharge to their homes. Mullett et al. [2] reported outcomes for 29 patients over the age of 80 with a Copeland surface replacement arthroplasty and a mean follow-up of 4.5 years in whom the Constant score improved from 15.1% to 77%. However, this was a heterogeneous group of patients, including individuals with documented rotator cuff tendon tears and the implantation of aTSA and hemiarthroplasty. Iriberri et al. [8] presented a more homogeneous group including only patients over 80 undergoing aTSA with an intact rotator cuff preoperatively. This was a relatively large series of 32 cases and they obtained good-to-excellent results comparable to patients around 70 years of age. Finally, Churchill et al. [3] published the outcomes for five cases of aTSA performed on patients over the age of 90 with intact rotator cuff and glenohumeral osteoarthritis. All patients had significant postoperative improvement in ROM, shoulder function (SST [Simple Shoulder Test] scores improved from a preoperative average of 2.0 to 7.4 at 2 years), and even general health status. In a 20-year follow-up of the Aequalis aTSA, Evans et al. noted that 72% of patients had died with the prosthesis in situ and acknowledged that older patients undergoing aTSA are unlikely to require revision of their prosthesis in their lifetime [25].
Reverse TSA is also a successful treatment option for patients older than 80 years. Triplet et al. [7] reported the outcomes of primary aTSA and rTSA in this group of patients. Although both treatment groups showed similar improve-ments in pain scores, functional outcome scores, and ROM at the 2-year follow-up, those treated with aTSA showed significantly more postoperative motion, higher satisfaction, and fewer complication and transfusion rates. As life expectancy is increasing, active older patients expect better functional outcomes as well as good pain relief in order to return to their recreational activities after surgery [26]. A recent systematic review evaluated the rate of return to sport in older patients who underwent aTSA and rTSA [27]. The overall rate of return to sport was 82%. Not surprisingly, patients undergoing aTSA returned at a higher rate (90%) compared to those undergoing rTSA (77%).
For this article no studies with human participants or animals were performed by any of the authors. All studies mentioned were in accordance with the ethical standards indicated in each case.
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