**6. Long-term outcomes**

Complications are a critical component of RTSA. Patients need to be counseled on intraoperative, perioperative, and notably, short-term complications. The most common intraoperative complications are glenoid or humeral fractures along with poor screw fixation [12]. The consequence of poor screw fixation is its lasting impact and conversion to long-term complications such as glenoid screw lucency. Zhou and colleagues [13] discussed the prevention techniques, such as hand reaming the humerus and preserving glenoid bone stock by avoiding reaming beyond subchondral bone margin. Postoperative short-term complications dominate the outcomes of RTSA and range from scapular notching, infection, dislocation, revision, nerve

Scapular notching is by far the most common complication during the first 24 months postoperative. Scapular notching has an incidence of 38%, 57%, 55% and 73% in four recent studies respectively [12, 15, 24, 25]. These findings oblige additional research to review instrumentation and confirm incidence levels on scapular notching in RTSA. In 2014, Feeley and colleagues [12] found that decreasing the neck-shaft angle or a higher inclination angle and 3 mm lateral offset of the glenosphere prosthesis decreased the rate of scapular notching by 16%. Furthermore, Zhou and colleagues [13] assert that continued complication management, by adding inferior placement of the glenosphere, is "the most important factor in the avoidance of inferior impingement." The next step is to investigate whether scapular notching will evolve, both de novo and from early to late stage scapular notching during short-term follow-up. An important question to consider is will the patient be free from scapular notching for the remainder of the prosthesis? [12] Feeley and colleagues [12] observed that of all the patients who did not experience scapular notching during the first 12 months (84% of patients), showed no new evidence of scapular notching during follow-ups up to 30 months. Conversely, Bacle and colleagues [15] found that after early scapular notching diagnoses were made, there was a 39% increase in the rate of notching beyond the 2-year follow-up period.

Another common short term complication deals with postoperative stability resulting in shoulder dislocations. Wierks [12] and colleagues as well as Bacle [15] and colleagues found 10% and 22% of dislocations occurred during the short term period. Of note, Bacle and colleagues [15] published that of the 15 dislocations documented in the sample size of 67, no cases were reported after the 2 year follow-up period. Zhou and colleagues [26] reviewed the most common and serious complications associated with RTSA and concluded that instability was a result of "lack of soft tissue tension, mechanical impingement, mismatch of the glenosphere and humeral socket size and improper version of the prosthesis". Therefore, to obtain the best outcome for patients, extensive knowledge of the prosthesis is imperative, along with understanding how to achieve soft tissue tension using vertical offset of your acromion—greater tuberosity distance and lateral offset of the tuberosity-glenoid distance [26]. Conversely, controversy exists within the RTSA literature regarding the decision to repair the subscapularis. Friedman and colleagues showed that subscapularis repair proclaimed no statistical significance over no repair [27]. In the study, 340 patients with RTSA plus repair had 0% dislocation rate, versus 251 patients with RTSA without repair showing a 1.2% dislocation rate; stating the claim that RTSA plus subscapularis repair is not indicated due to the absence of increase in overall complication rates [27]. Lastly, infections can have serious ramifications on patient satisfaction as well as the overall outcomes of the RTSA, resulting in one or two-stage revisions. A study conducted by Wierks

palsy, or even heterotopic ossification.

92 Advances in Shoulder Surgery

Thus, superfluous research is essential to answer this question.

The patient's age at the time of the arthroplasty plays a critical role in the survival of the prosthesis; younger patients (i.e., < 55 years of age) are more likely to be active in the workforce, while older patients are less likely to participate in physically strenuous activities and be retired [16]. In younger patients, prosthesis survival can exceed 10 years. For example, Bacle and colleagues [15] observed a 93% implant survival rate at 10 years; whereas Ek and colleagues [28] observed an implant survival rate of 88% at 5 years and 76% at 10 years postoperatively, regardless of any complications that may have arisen.

The RTSA has been shown to improve pain, strength, range of motion in abduction, external rotation, and forward flexion; in addition to showing improvement in metrics, such as ASES, SST, CMS, SPADI, and UCLA Should and UCLA Shoulder Score [16, 23, 24, 29]. Outcomes beyond the 24-month mark may be impacted by multiple variables, some of which include, prosthesis sizes, involvement of fracture, primary versus revision RTSA, and the lifestyle or activity level of the patient. In regards to repair of proximal humeral fractures, RTSA was found to provide superior results to a hemiarthroplasty for at least 5 years, respectively [30]. Muller and colleagues [24] investigated the size of the glenosphere, 36 mm and 44 mm, on functional outcomes following RTSA and found that both groups exhibited the most substantial progress in the first 6–24 months, followed by a plateau. Patients' progress was monitored by measuring flexion, abduction, external rotation at 0° and 90° of abduction, internal rotation at 90° of abduction, CMS, SPADI, and strength (kg) in abduction. Interestingly, Anakwenze and colleagues [31] found that a higher body mass index (BMI) put a patient at risk for deep surgical site infection (SSI) up to 3 years following RTSA. Their study looked at the effects of increased BMI on postoperative outcomes following a RTSA and total shoulder arthroplasty (TSA). Every 5 kg/m [2] increase in BMI was associated with higher risk of 3-year deep SSI [31]. In addition to BMI, tobacco use influences the success of the prosthesis up to 12 years after an RTSA [32]. Hatta and colleagues [32] found that current smokers had an increased risk for infection, component loosening, and fractures compared to non-smokers. Specifically, they found that the percentage of patients with periprosthetic fractures jumped 20% at the 9 year mark after RTSA [32].

Although, as previously stated, this study implies 24 months as the short-term interval for outcomes following an RTSA, short-term complications have the potential to extend into the long-term if not addressed or managed appropriately—eventually affecting the longevity of the prosthesis. More commonly, long-term complications include glenoid and/or humeral component loosening, polyethylene component wear, and scapular notching. Less common long-term complications include deep SSI, dislocation, readmission, and fracture; which primarily occur within the first 2 years postoperatively. As mentioned above, glenoid or humeral loosening is the most common complication observed 2 years after RTSA, particularly with an increased risk following a previously failed shoulder arthroplasty and excess mechanical load related to increased BMI [15, 33]. Further, the incidence of component loosening doubles between the second and fifth year follow-up as reported by Alentorn-Geli and colleagues [29]. Particlization of the polyethylene component may be of concern with RTSA in younger patients due to necessary durability and lifespan of the implant. Riley and colleagues [34] investigated the outcomes following RTSA using a metal-on-metal design and concluded that it is not an acceptable alternative to RTSA in young patients; they maintain that the polyethylene component is the more suitable option. Ek and colleagues [28] conducted a study evaluating RTSA in patients younger than 65 years of age using two groups: revision RTSA and primary RTSA. This study observed an increased incidence of scapular notching at less than 12 months follow-up and greater than 10 years follow-up; with 56% of patients experiencing some degree of scapular notching overall [28]. Conversely, Mollon and colleagues [34] reported that only 10% of patients experienced scapular notching; noting that risk factors for scapular notching included lower body weight, lower BMI, and RTSA on the non-dominant upper extremity. It is also worth mentioning the correlation between longer-term follow-up and increasing incidence of scapular notching [34]; which may be attributed to variation in size and placement of the glenosphere, and center of rotation of the prosthesis.

**Author details**

Sydney C. Cryder<sup>1</sup>

Athens, United States

Medicine, Athens, United States

United States

**References**

2015;**35**:1-7

\*, Samuel E. Perry2

Elbow Surgeons…[et al.]. Jan 2015;**24**(1):150-160

American volume. Dec 2010;**92**(Suppl 2):23-35

\*Address all correspondence to: sc323908@ohio.edu

and Elizabeth A. Beverly3

Current Outcomes Following Reverse Total Shoulder Arthroplasty: A Composite

http://dx.doi.org/10.5772/intechopen.72545

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1 Department of Medicine, Ohio University, Heritage College of Osteopathic Medicine,

2 Department of Graduate Medical Education, Adena Health System, Chillicothe,

3 Department of Family Medicine, Ohio University, Heritage College of Osteopathic

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