**5. Short-term outcomes**

**Table 1** reviews the outcome measures and length of follow-up from numerous surgical studies. Based on these findings, short-term outcomes for RTSA occur postoperatively within the first 24 months. It also addresses the variation in components and metrics used in each study.

RTSA significantly improves functionality, pain, and satisfaction; but when are patients expected to experience peak performance with a new prosthesis? Is there a point in time when a patient should expect a plateau in their improvements over time? In 2015, Simovitch and colleagues [23] demonstrated that at the 6-month follow-up, less than 5% of patients reported decreases in SST, UCLA Shoulder Score, CMS, ASES, SPADI. More importantly, "full improvement" was achieved in the 12–24 month range [23]. Thus, they concluded that the majority of improvement occurred within the first 6 months, as evidenced by the scores for each of the five measures [23]. These findings stress the importance of patient selection, expectations for RTSA, expertise in intraoperative optimization, and strict postoperative physical therapy management. The concept of rapid improvement during the first 6 months with plateau at 12 months was also reported by Muller and colleagues in 2017 [24], in which flexion, abduction, and external rotation in 90 degrees of abduction demonstrated profound increases by 42°, 38° and 33° respectively at 6 months. Additional follow-ups at 12, 24, and 60 months displayed minimal additional improvement [24]. Supplementary evidence of RTSA success was seen by Yoon and colleagues [25] in 2017 with forward flexion increase of 64°, external rotation increase of 13° and pain reduction of (−3) at 12 months postoperatively.

Two factors that have been shown to increase CMS and ROM testing during the short-term period are deltoid volume [25] and glenosphere size [24] respectively. Preoperative deltoid muscle volume was an independent prognostic factor for functional outcomes with CMS (p = 0.011), underscoring the importance of patient selection and discussing the potential for negative outcomes such as atrophied deltoid muscle [25]. Likewise, Muller and colleagues [24] conducted a retrospective analysis in 2017, to demonstrate that patients that had received a 44 mm glenosphere had greater external rotation in adduction and abduction strength over the 36 mm glenosphere. Moreover, they found no significant differences in functional scores or complication rates [24].


and "throw ball overhand" may not be relevant [19]. Patient-reported pain is an outcome that necessitates acknowledgement, which may be quantified by utilizing the VAS [21]. The VAS uses a line measuring 100 mm with pain extremes indicated on either end; no pain and worst pain [21]. The patient marks along the continuum where he/she believes their pain is best described; the score is then represented by a distance in millimeters [22]. Finally, the SST, is used to evaluate patient-reported functionality associated with various shoulder pathology, including rotator cuff arthropathy, osteoarthritis, rheumatoid arthritis, and adhesive capsulitis [17, 18]. This questionnaire consists of 12 questions that ask the patient whether he/she may

**Table 1** reviews the outcome measures and length of follow-up from numerous surgical studies. Based on these findings, short-term outcomes for RTSA occur postoperatively within the first 24 months. It also addresses the variation in components and metrics used

RTSA significantly improves functionality, pain, and satisfaction; but when are patients expected to experience peak performance with a new prosthesis? Is there a point in time when a patient should expect a plateau in their improvements over time? In 2015, Simovitch and colleagues [23] demonstrated that at the 6-month follow-up, less than 5% of patients reported decreases in SST, UCLA Shoulder Score, CMS, ASES, SPADI. More importantly, "full improvement" was achieved in the 12–24 month range [23]. Thus, they concluded that the majority of improvement occurred within the first 6 months, as evidenced by the scores for each of the five measures [23]. These findings stress the importance of patient selection, expectations for RTSA, expertise in intraoperative optimization, and strict postoperative physical therapy management. The concept of rapid improvement during the first 6 months with plateau at 12 months was also reported by Muller and colleagues in 2017 [24], in which flexion, abduction, and external rotation in 90 degrees of abduction demonstrated profound increases by 42°, 38° and 33° respectively at 6 months. Additional follow-ups at 12, 24, and 60 months displayed minimal additional improvement [24]. Supplementary evidence of RTSA success was seen by Yoon and colleagues [25] in 2017 with forward flexion increase of 64°, external

rotation increase of 13° and pain reduction of (−3) at 12 months postoperatively.

Two factors that have been shown to increase CMS and ROM testing during the short-term period are deltoid volume [25] and glenosphere size [24] respectively. Preoperative deltoid muscle volume was an independent prognostic factor for functional outcomes with CMS (p = 0.011), underscoring the importance of patient selection and discussing the potential for negative outcomes such as atrophied deltoid muscle [25]. Likewise, Muller and colleagues [24] conducted a retrospective analysis in 2017, to demonstrate that patients that had received a 44 mm glenosphere had greater external rotation in adduction and abduction strength over the 36 mm glenosphere. Moreover, they found no significant differences in functional scores

perform the given activity [18].

88 Advances in Shoulder Surgery

**5. Short-term outcomes**

or complication rates [24].

in each study.


**Study Sample size**

> 912 60–78 years

> 41 53–83 years

> 20 45–88 years

> 17 45–91 years

> 35 66–84 years

3–21 months

10–67.7 months

12–35 months

flexion; ER = external rotation; BMD = bone mineral density.

2 weeks– 139 months

2–7.3 years Scapular

notching Revision Nerve palsy Heterotopic ossification

Fracture Poor screw fixation Nerve palsy Infection/ Abscess Dislocation Revision Heterotopic ossification Scapular notching

Dislocation Component migration

Scapular notching A/C joint separation Acromial fracture

ASES = American shoulder and elbow surgeons; SPADI = shoulder pain and disability index; ROM = range of motion; UCLA = University of California Los Angeles score; SST = simple shoulder test; VAS = visual analogue score; FF = forward

**Table 1.** Comparison of outcome measures and length of follow-up for patients undergoing reverse total shoulder

**Simovitch et al (2015)**

**Statz et al (2016)**

**Wierks et al (2007)**

**Williams et al (2017)**

**Yoon et al (2017)**

arthroplasty.

**Age Follow up Complications Component** 

**variability**

system (Exactech)

Current Outcomes Following Reverse Total Shoulder Arthroplasty: A Composite

Encore reverse shoulder Prosthesis (DJO Surgical) Delta III, Delta Xtend (DePuy) Comprehensive prosthesis (Biomet) Aequalis Reversed Shoulder (Tournier)

DePuy reverse shoulder prosthesis Tournier reverse shoulder prosthesis

Biomet reverse adapter (Bio-Modular to Comprehensive conversion)

Aequalis reverse arthroplasty system (Tournier)


**Risk factors Scoring** 

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


Increased BMI Previous shoulder surgery Tobacco use Diabetes mellitus



Increase BMI Diabetes mellitus Hypertension Decreased BMD

ASES score

VAS ASES score Constant score

SST

**Mechanism**

91

ASES score UCLA score Constant score

ROM ASES score Current Outcomes Following Reverse Total Shoulder Arthroplasty: A Composite http://dx.doi.org/10.5772/intechopen.72545 91


**Study Sample size**

90 Advances in Shoulder Surgery

591 50–93 years

27 55–85 years

476 53–90 years

68 68–79 years

67 21–54 years

226 64–72 years

**Friedman et al (2017)**

**Jonusas et al (2017)**

**Mollon et al (2016)**

**Muller et al (2017)**

**Otto et al. (2017)**

**Randelli et al (2015)** **Age Follow up Complications Component** 

Component instability Scapular notching

ossification Tubercule malposition

Scapular notching Dislocation Infection Component Loosening Humeral fracture Scapular fracture

Glenoid migration Component loosening

Scapular notching

3.8 years Revision

Infection Fracture

Humeral lucency Glenoid screw lucency Fracture (humeral, scapular) Humeral dissociation Infection Instability Revision

45 months Heterotopic

24 month minimum (37 month mean)

22–93 months

6–60 months

24–144 months **variability**

Equinoxe rTSA (Exactech)

Arrow shoulder system with less medialized CoR

Equinoxe rTSA (Exactech) 36 mm, 40mm, or 42mm glenosphere lateralized 2.3mm

SMR reverse shoulder system (Lima Switzerland

36mm or 40mm glenosphere

Reverse shoulder system (DJO Surgical)

SA)

**Risk factors Scoring** 



Increased age Increased BMI

**Mechanism**

ASES score UCLA score

CMS SPADI

CMS

ROM ASES score CMS SST

Increased age CMS SPADI

SST

ASES score

ASES score

Prior shoulder surgery

Delta III - Constant Score

ASES = American shoulder and elbow surgeons; SPADI = shoulder pain and disability index; ROM = range of motion; UCLA = University of California Los Angeles score; SST = simple shoulder test; VAS = visual analogue score; FF = forward flexion; ER = external rotation; BMD = bone mineral density.

**Table 1.** Comparison of outcome measures and length of follow-up for patients undergoing reverse total shoulder arthroplasty.

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 palsy, or even heterotopic ossification.

and colleagues [12] in 2009, had a 5% infection rate and a study by Bacle and colleagues [15] in 2017, had an infection rate of 12%. It is important to emphasize that Bacle and colleagues [15] documented 8 infections within the first 24 months as compared to only 2 cases in the 12 year follow-up period. In the same study, with regards to revision cases in the short-term period, 6 out of the 8 revision surgeries were caused by infections [15]. Thus, postoperative infections that occur in the first two years are the most common reason for revision surgery. In the review conducted by Zhou and colleagues [26] in 2015, they compared primary cases and revision cases, to find that revision cases were statistically higher than primary cases with regards to infections rates, 5.9% vs. 2.9% respectively. *Propionibacterium acnes* and *Staphylococcus epidermidis* were the most commonly cultured organisms. Recommendations to decrease infections include continuation of preoperative antibiotics within one hour of incision and use of antibiotic-impregnated cement for surgeries that employ cement the humeral component [26].

Current Outcomes Following Reverse Total Shoulder Arthroplasty: A Composite

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

93

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 post-

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

operatively, regardless of any complications that may have arisen.

**6. Long-term outcomes**

9 year mark after RTSA [32].

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. Thus, superfluous research is essential to answer this question.

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 and colleagues [12] in 2009, had a 5% infection rate and a study by Bacle and colleagues [15] in 2017, had an infection rate of 12%. It is important to emphasize that Bacle and colleagues [15] documented 8 infections within the first 24 months as compared to only 2 cases in the 12 year follow-up period. In the same study, with regards to revision cases in the short-term period, 6 out of the 8 revision surgeries were caused by infections [15]. Thus, postoperative infections that occur in the first two years are the most common reason for revision surgery. In the review conducted by Zhou and colleagues [26] in 2015, they compared primary cases and revision cases, to find that revision cases were statistically higher than primary cases with regards to infections rates, 5.9% vs. 2.9% respectively. *Propionibacterium acnes* and *Staphylococcus epidermidis* were the most commonly cultured organisms. Recommendations to decrease infections include continuation of preoperative antibiotics within one hour of incision and use of antibiotic-impregnated cement for surgeries that employ cement the humeral component [26].
