Subscapularis management in anatomic total shoulder arthroplasty: A systematic review and network meta-analysis

Abstract

Background

This systematic review and network meta-analysis compare clinical outcomes of three different subscapularis management techniques in anatomic total shoulder arthroplasty: lesser tuberosity osteotomy, subscapularis peel, and subscapularis tenotomy.

Methods

PubMed, Web of Science, Embase, and Cochrane's trial registry were searched in July 2021. Comparative studies and case series evaluating the outcomes of these three techniques were included. The network meta-analysis was performed only on comparative studies.

Results

Twenty-three studies were included. Both lesser tuberosity osteotomy and subscapularis peel had significantly higher Western Ontario Osteoarthritis Scores compared to subscapularis tenotomy, but no difference in American Shoulder and Elbow Society Scores. Subscapularis peel had superior external rotation compared to lesser tuberosity osteotomy. However, no difference was found in external rotation between subscapularis peel and subscapularis tenotomy or between subscapularis tenotomy and lesser tuberosity osteotomy. The overall weighted average for lesser tuberosity osteotomy bony union was 93.6%, whereas the overall weighted average for subscapularis tendon healing was 79.4% and 87% for subscapularis tenotomy and subscapularis peel, respectively.

Discussion

This network meta-analysis demonstrated that lesser tuberosity osteotomy and subscapularis peel were associated with the high union and subscapularis healing rates and may be associated with improved shoulder function and quality of life, compared to subscapularis tenotomy. Lesser tuberosity osteotomy and subscapularis peel demonstrate a trend of superior outcomes compared to subscapularis tenotomy during anatomic total shoulder arthroplasty.

Introduction

Anatomic total shoulder arthroplasty (aTSA) is a common and effective treatment of shoulder arthritis.^1,2 Given the excellent clinical outcomes, it is unsurprising that the utilization of aTSA is quickly growing. In 2017, ³ 12.5 of every 100,000 surgeries performed were an aTSA. Due to the rapidly increasing utilization of TSA, it is important for orthopedic surgeons to understand the intricacies of its surgical technique. One area of technique variability between surgeons is the management of the subscapularis tendon during the surgical approach.

The subscapularis tendon is encountered during the deltopectoral approach and must be mobilized to gain access to the glenohumeral joint. The aTSA surgical technique originally described by Neer involved a subscapularis tenotomy (ST). ⁴ In this technique, the tendon was vertically incised with a cuff of insertional tissue preserved for later repair on the lesser tuberosity. The two ends of the tendon were repaired end-to-end following component placement and during closure. Subsequently, a lesser tuberosity osteotomy (LTO) was described, ⁵ allowing for direct repair to bone at the end of the case. This technique allows for bony healing, which may be biomechanically advantageous compared to tendinous healing.^6,7 Lastly, a third technique, the subscapularis peel (SP), has been described where the subscapularis is dissected directly from its insertion on the lesser tuberosity. ⁸ The tendon is then repaired directly to the bone using one of a variety of techniques, often utilizing heavy nonabsorbable sutures, bone tunnels, and/or suture anchors.^6,9,10

To evaluate the effectiveness of each technique, objective measures are required. The American Shoulder and Elbow Society (ASES) Score and Western Ontario Osteoarthritis of the Shoulder (WOOS) index are validated tools for scoring shoulder function that are commonly utilized after shoulder arthroplasty.^11–13 Shoulder range of motion (ROM), strength and surgical complications also serve as meaningful comparison points. There is a high degree of variability in reporting post-surgical outcomes following aTSA and because of this, it is challenging to ascertain optimal subscapularis management technique. Due to this variability, the American Academy of Orthopaedic Surgeons has been unable to recommend one surgical technique over another. ¹⁴ Moreover, prior systematic reviews have not demonstrated significant functional differences between all three subscapularis management techniques.^15–17 Compared to the last meta-analysis, ¹⁵ three additional comparative studies were sought in this study. Furthermore, all non-comparative studies in the literature were included to gain a further understanding of subscapularis healing and LTO union rates. To further elucidate which method is preferable, the aim of this study was to provide an updated comparison between different techniques for subscapularis management in aTSA through network meta-analyses techniques.

Methods

This systematic review and network meta-analysis were conducted with adherence to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. ¹⁸

The primary aim of this study was to compare shoulder function scores between LTO, SP, and ST techniques. The secondary outcomes were shoulder ROM and strength, subscapularis tendon integrity on imaging, union rate of the LTO, and complication rates.

Eligibility criteria

Included studies were clinical comparative and non-comparative studies investigating the outcomes of interest utilizing different subscapularis management techniques during aTSA—LTO, SP, or ST. The exclusion criteria were non-clinical biomechanical studies, case reports, reviews, inaccessible full text, articles publishing in languages other than English, and those not reporting on outcomes of interest.

Information sources and search strategy

PubMed, Web of Science, Embase and Cochrane's trial registry were searched in July 2021. Keywords included: “Shoulder” AND (“Arthroplasty” OR “Replacement”) AND (“Subscapularis Peel” OR “Subscapularis Tenotomy” OR “Lesser Tuberosity Osteotomy”). Studies were screened by titles and abstracts. A full-text review was performed if a study matched the eligibility criteria. The search strategy was performed by two authors independently.

Data collection process and data items

Data were collected independently by two authors. The data items that were collected included: the first authors’ surnames, study year and location, age, sex, number of patients, diagnoses, form of subscapularis management, follow-up time points, The ASES scores, the WOOS index, shoulder ROM, internal rotation strength, LTO union rate, subscapularis tendon integrity on imaging, and overall complications.

Qualitative synthesis

The qualitative analysis was performed with two different tools. Randomized controlled trials (RCTs) were evaluated with the Cochrane Risk of Bias assessment tool. ¹⁹ The tool contains five domains which assess the randomization, adherence to intended treatments, missing outcomes, measurement bias, and reporting bias. Whereas, non-randomized studies, including cohort studies and case series, were evaluated with the methodological index for non-randomized studies (MINORS) criteria which consists of 12 items. ²⁰ The first eight items are designed to evaluate the quality of either comparative or non-comparative studies. Four additional items are added to further evaluate comparative studies only. Each study was assessed by two authors independently.

Quantitative synthesis

The network meta-analysis was performed with the use of R software (version 3.5.1; R Foundation for Statistical Computing, Vienna, Austria) and the “netmeta” R package (version 0.9-6; R Foundation for Statistical Computing). The outcomes were estimated with the use of a 95% confidence interval (CI), and a significant difference in outcomes was considered statistically significant if the P-value was less than 0.05. The mean difference (MD) was used for estimating the treatment effect of continuous outcomes. The Hedges G standard mean difference (SMD) was used for estimating the effect on the postoperative strength indices due to potential variability in measurement among studies. P-scores were generated for outcome measure comparisons to rank the three subscapularis management techniques. A higher P-score indicates that on average one treatment is superior compared to competing treatments for each outcome measure. The meta-analytic models were based on random effects with the use of the DerSimonian–Laird method as a heterogeneity variance estimator.

Only comparative studies were included in the network meta-analysis for the following comparative outcomes: ASES score, WOOS index, shoulder ROM, and shoulder internal rotation strength. ST was considered as the reference treatment in this network meta-analysis unless there was a significantly inferior treatment. For each non-comparative outcome such as LTO union and subscapularis tendon healing rates, both comparative and non-comparative studies results were combined to provide an overall weighted average for each outcome. Complications were summarized and were not pooled due to heterogeneity in the level of evidence.

Results

Study selection

The search strategy resulted in 524 articles, of which 279 articles were duplicated and removed. The records were then screened by titles and abstracts against the eligibility criteria, which resulted in 237 exclusions. Next, 19 of the 42 remaining articles were excluded for either being a case report, review article, biomechanical study, or included revision TSA. A total of 23 studies were eligible for inclusion (Figure 1).

Figure 1.

Search strategy flowchart. TSA: total shoulder arthroplasty.

Study characteristics

Table 1 displays the characteristics of the included studies. Out of the 23 included studies, three were RCTs, seven were cohort studies, and 13 were case series. A total of 1787 patients underwent shoulder arthroplasty, of which 1041 had LTO, 455 underwent ST, and 292 underwent SP. The mean age among studies ranged from 60 to 71.3 years, except for the case series by Gerber et al. ⁵ where patients had a mean age of 57 years. Most indications were primary osteoarthritis of the shoulder, with minor cases of rheumatoid arthritis and avascular necrosis. The follow-up period ranged between 12 months and 50 months. There were two articles by Lapner et al. published in 2012 ⁸ and 2013 ²¹ with a similar population, however, each article addressed different outcomes. Each article's sample was used in this meta-analysis for the outcome it reported. Armstrong et al. had two publications in 2006 ²² and 2016, ²³ with different populations in both articles. The preoperative quality of the subscapularis tendon was evaluated differently across studies. Nine studies had only reported that aTSA was performed for primary osteoarthritis without preoperative imaging documenting subscapularis muscle quality, with the exclusion of inflammatory arthritis, osteonecrosis, traumatic or post-traumatic conditions and prior open shoulder surgery.^6,22,24–30 One study reported that subscapularis integrity was confirmed with physical examination in addition to applying the aforementioned exclusion criteria. ³¹ In contrast, aTSA was performed for primary osteoarthritis in addition to rheumatoid arthritis in two studies;^8,32 in addition to posttraumatic osteoarthritis and trauma in one study; ³³ or in addition to rheumatoid arthritis and avascular necrosis in two studies;^34,35 or in addition to inflammatory and instability arthritis or trauma in one study. ⁵ Four studies performed aTSA in glenohumeral osteoarthritis only and confirmed subscapularis integrity based on preoperative physical examination and advanced imaging in selected cases with an equivocal physical examination.^36–39 Three studies did not specify clear eligibility criteria or preoperative subscapularis evaluation.^40–42

Table 1.

Baseline characteristics of included studies.

Study	Design, LoE	Subscapularis management	Mean age	Male %	Diagnosis	TSA	HA	Follow-up
O’Brien 2020 24	RCS, III	LTO 28/ST 37	68.8/64.8	85.7/56.7	Primary OA	100%	0%	28.4 mo/33.4mo
Johnson 2020 40	CS IV	LTO 142	65.2	50.80%	NR	100%	0%	12 mo
Lapner 2019 25	RCT, II	ST 37/SP 44	69.7	48%	Primary OA	100%	0%	24 mo
Levine 2019 36	RCT, I	ST 30/LTO 29	NR	NR	Primary OA	100%	0%	24 mo
Aibinder 2019 26	RCS, III	ST 68/LTO 55/SP 65	64/62/60	54%/51.5%/42%	Primary OA	100%	0%	24 mo
Levy 2019 41	CS IV	LTO 189	69.5	58.20%	NR	100%	0%	50 mo
Baumgarten 2018 27	PPS, I	ST 36	70.3	55.50%	Primary OA	100%	0%	12 mo
Mason 2018 43	RCS, III	ST 24/LTO 15	68.2/70.2	71%/60%	Primary OA 37, RA 2	100%	0%	18.5 mo/20.6 mo
Shafritz 2017 44	RCS, III	SP 46/44 LTO	61.7/64.6	62.20%	Primary OA	100%	0%	48 mo
Gobezie 2017 42	CS IV	SP 60	63.9	65%	Primary OA	100%	0%	15 mo
Armstrong 2016 23	CS IV	ST 30	64	50%	Primary OA	100%	0%	24 mo
Small 2014 38	CS IV	LTO 220	62.5	54.1	NR	100%	0%	Range 6–78 mo
Buckley 2014 32	RCS, III	ST 32/LTO 28	68.4/68.3	62/54	OA (94–96%)	100%	0%	31.7 mo/22.1 mo
Liem 2012 31	CS IV	SP 23	71.3	39	OA	61%	39%	43 mo
Lapner 2012/20138,21	RCT, I	SP 39/LTO 40	65.3/70.4	39	OA (91%/98%)	80%/83%	20%/16%	24 mo
De Wilde 2012 39	CS IV	LTO 36	68	28	OA	100%	0%	18 mo
Jandhyala 2011 28	RCS, III	ST 10/LTO 26	64/68.4	60/53.8	OA (97.2%)	100%	0%	38 mo
Scalise 2010 29	RCS, III	SP 15/LTO 20	67/69	46.6%/70%	OA	100%	0%	39 mo/30 mo
Jackson 2010 30	CS IV	ST 15	67.1	NR	OA	100%	0%	31.6 mo
Krishnan 2009 6	CS IV	LTO 100	63	41	NR	100%	0%	31 mo
Qureshi 2008 34	CS IV	LTO 30	66	NR	OA (76%)/AVN (16%)	100%	0%	13 mo
Armstrong 2006 22	CS IV	ST 30	70.4	46	OA	100%	0%	19 mo
Gerber 2005 45	CS IV	LTO 39	57	50	OA (43%)/inflammatory (25%)	100%	0%	39 mo

LOE: level of evidence; LTO: lesser tuberosity osteotomy; ST: subscapularis tenotomy; SP: subscapularis peel; CS: cohort study; RCS: retrospective cohort study; PPS: prospective prognostic study; RCT: randomized controlled trial; OA; osteoarthritis; NR: not reported. TSA: total shoulder arthroplasty; HA: hemiarthroplasty; mo: months.

Qualitative analysis

The risk of bias assessment demonstrated low risks of bias for all three RCTs (Appendix Figure 1). The MINORS score for the seven non-randomized comparative studies ranged from 18 to 23 (out of 24). The cohort studies by Jandhyala et al., ²⁸ Buckley et al., ³² and Scalise et al. ²⁹ had the highest MINORS score. For case series, the MINORS score ranged between 8 and 14 (out of 16). Armstrong et al. ²³ in 2016 had the highest MINORS score for case series (14 out of 16). Most cohort and case series studies had low scores because of the lack of statistical power calculation and/or the lack of outcome assessors blinding. The MINORS scores are summarized in Appendix Table 2.

The ASES score

A total of five studies reported post-operative ASES scores at an average follow-up of 23.3 months.^8,24–26,36 The number of patients for the ASES comparison was 250 for LT, 227 for LP and 210 for LTO. The highest P-score was achieved by ST (0.72). The second highest P-score was achieved by SP (0.69), while LTO (0.08) had the lowest P-score (0.08). There was no statistically significant difference in ASES scores between LTO and ST (MD: 3.35; 95% CI: −7.9, 1.23) or SP and ST (MD: −4.2; 95% CI: −4.2, 3.9) (Figure 2).

Figure 2.

Forest plot representing the network meta-analysis comparison of American Shoulder and Elbow Society (ASES) scores between lesser tuberosity osteotomy (LTO), subscapularis peel (SP), and subscapularis tenotomy (ST). MD: mean difference; CI: confidence interval.

WOOS index

A total of four studies reported post-operative WOOS index with an average follow-up of 23.5 months.^8,25,32,43 The total number of patients for the WOOS comparison was 97 patients for LP, 103 patients for LT, and 86 patients for LTO. The highest P-score was achieved by LTO (0.84), followed by SP (0.65). There was no statistically significant difference between LTO and SP (MD 1.5; 95% CI: −4.8, 7.8). On the other hand, ST had the lowest P-score (0.01), and it had significantly lower WOOS indices compared to both LTO and SP. The MD was 8.36 (95% CI: 2.8, 13.9) between LTO and SP, and 6.85 (95% CI: 0.33. 13.4) between SP and ST (Figure 3).

Figure 3.

Forest plot representing the network meta-analysis comparison of Western Ontario Osteoarthritis of the Shoulder (WOOS) indices between lesser tuberosity osteotomy (LTO), subscapularis peel (SP), and subscapularis tenotomy (ST). MD: mean difference; CI: confidence interval.

Shoulder forward elevation range of motion

Seven studies reported shoulder forward elevation ROM with an average follow-up of 27.9 months.^{24–26,28,32,36,44} The total number of patients for the forward elevation comparison was 229 patients for SP, 292 for ST, and 265 patients for LTO. The highest P-score was achieved by LTO (0.81). ST had a P-score of 0.61, and SP had the lowest P-score of 0.07. There was no difference between SP and ST (SMD: −0.19; 95% CI: −0.48, 0.1), and no difference between SP and LTO (SMD: 0.06; 95% CI: −0.19, 0.3) (Figure 4).

Figure 4.

Forest plot representing the network meta-analysis comparison of forward elevation range of motion (ROM) between lesser tuberosity osteotomy (LTO), subscapularis peel (SP), and subscapularis tenotomy (ST). SMD: standardized mean difference; CI: confidence interval.

Shoulder abduction range of motion

Only three studies reported shoulder abduction ROM at an average follow-up of 31.9 months.^24,28,32 Only ST and LTO were reported in these studies, therefore, a direct meta-analysis was performed between both treatments only. The total number of patients for the ST group was 79 patients, and 82 patients for the LTO group. There was no significant difference between LTO and ST (SMD: −0.03; 95% CI: −0.35, 0.29) (Figure 5).

Figure 5.

Forest plot representing the network meta-analysis comparison of abduction range of motion (ROM) between lesser tuberosity osteotomy (LTO) and subscapularis tenotomy (ST). SMD: standardized mean difference; CI: confidence interval.

Shoulder external rotation range of motion

Six studies reported external rotation ROM at an average follow-up of 28 months.^{24–26,28,29,32} The total number of patients was 277 for ST, 183 for SP and 212 for LTO. SP achieved the highest P-score (0.97), whereas both ST and LTO had lower P-scores of 0.45 and 0.07, respectively. SP had a statistically significant increase in external rotation when compared to LTO (SMD: 0.5; 95% CI: 0.11, 0.9) (Figure 6). There was no difference in external rotation between ST and LTO (SMD: 0.17; 95% CI: −0.13, 0.46). Likewise, no difference was found between SP and ST (SMD: 0.34; 95% CI: −0.02, 0.7).

Figure 6.

Forest plot representing the network meta-analysis comparison of external rotation range of motion (ROM) between lesser tuberosity osteotomy (LTO), subscapularis peel (SP), and subscapularis tenotomy (ST). SMD: standardized mean difference; CI: confidence interval.

Shoulder internal rotation strength

Six studies reported internal rotation strength by using a hand-held dynamometer at an average follow-up of 28 months.^{8,24,25,29,32,36} The total number of patients for the internal rotation strength comparison was 151 patients for ST, 83 for SP, and 145 for LTO. All force units were converted from Newtons or Pounds force to Kilograms force. SP achieved the highest P-score (0.8), followed by LTO (0.68) and ST (0.01). There was no difference in internal rotation strength between SP and LTO (SMD: 0.07; 95% CI: −0.37, 0.5). However, both LTO and SP had statistically significant increases in internal rotation strength when compared to ST (Figure 7). The SMD between SP and ST was 0.47 (95% CI: 0.03, 0.91), and the SMD between LTO and ST was 0.39 (95% CI: 0.08, 0.71).

Figure 7.

Forest plot representing the network meta-analysis comparison of internal rotation strength between – (LTO), subscapularis peel (SP), and subscapularis tenotomy (ST). SMD: standardized mean difference; CI: confidence interval.

Non-comparative outcome: LTO union, subscapularis tendon integrity, and complications

No meta-analytic comparisons were made for the LTO union rates or subscapularis tendon healing rates. The weighted overall average was pooled from both comparative and non-comparative to provide comprehensive rates. Union rates of LTO were reported in 15 studies.^{6,8,24,26,28,29,32,34,36,38–41,44,45} Union of the LTO was assessed in all studies by plain shoulder radiographs, except in three studies by Gerber et al., ⁴⁵ Levine et al. ³⁶ and Lapner et al. ²¹ where the union was assessed by computed tomography. The overall weighted average for LTO complete union was 93.6% (884 unions out of 988 LTOs). Subscapularis integrity was reported in seven studies^{22,23,25,29,30,32,36} for ST, and in three studies for SP.^8,25,42 Integrity of the subscapularis tendon was assessed by ultrasonography except in one study by Lapner et al. ²¹ in 2013 where computed tomography was used to assess integrity following SP. The overall weighted average for subscapularis tendon healing was 79.4% (151 healed tendons out of 190) for ST, and 87% (131 healed tendon out of 150) for SP. A summary of all complications encountered in the included studies is provided in Appendix Table 2.

Discussion

This meta-analysis shows that although there was no difference in ASES scores, both LTO and SP had significantly higher WOOS scores showing improved quality of life as reported by patients. It also identified a greater internal rotation strength for LTO and SP compared to ST. While patients undergoing LTO had less post-operative external rotation when compared with SP, there was no statistically significant difference between LTO and ST. Additionally, we found that LTO is associated with the greatest union/healing rate compared to both SP and ST. Overall, the results of this meta-analysis suggest that LTO and SP may provide superior clinical outcomes when compared with ST.

Subscapularis dysfunction following shoulder arthroplasty has been shown to lead to poor clinical outcomes, including, but not limited to instability, weakness, pain, and decreased motion.^46–48 Despite overall satisfactory outcomes following TSA, rates of subscapularis dysfunction have been reported to be as high as 67%. ³⁶ Therefore, identifying the optimal surgical technique that preserves function is critical in optimizing postoperative function. To date, there remains considerable controversy regarding subscapularis management during TSA. ¹⁵

In the early 2000s, there was renewed interest in subscapularis management after studies highlighted subscapularis dysfunction following ST. ³⁵ These studies contributed to a shift in surgical practice to maintain subscapularis function during the surgical approach, popularizing LTO and SP approaches, techniques that would potentially allow for improved healing. Our pooled analysis found that the overall weighted average for LTO complete union was 93.6% compared to subscapularis healing rates of 87% and 79% for SP and ST, respectively. Despite a focus on healing rates, it is important to note that studies have reported mixed findings on the significance of healing. For example, while some studies have shown that subscapularis tendon healing is important for functional outcomes, ³² others have noted that subscapularis integrity may have limited clinical significance.^30,31 However, as this meta-analysis demonstrates, there is a clear correlation between increased functional scores and LTO and SP, techniques associated with higher union/healing rates compared to ST.

There is heterogeneity in how subscapularis integrity is assessed. For example, while the belly-press test was originally a validated method of assessing subscapularis muscle healing, ultrasound has recently shown that this physical exam maneuver has poor positive predictive value for detecting rupture. ³⁵ However, ultrasound is operator dependent and may miss small tears of the subscapularis tendon. ¹⁵ In our analysis, LTO union was assessed by radiographs or CT, and integrity of the subscapularis tendon was assessed with ultrasound or CT. While CT can show bone-to-bone healing, its ability to assess for subscapularis muscle/tendon healing may be significantly less sensitive. ¹⁵ Radiographs have also been shown to have limitations in their ability to assess union. Previous studies have noted up to a 17% incidence of inability to visualize the osteotomy site. Because there is significant variability in assessing subscapularis integrity with limitations of each method, further study is needed to accurately gauge subscapularis healing following shoulder arthroplasty.

Two clinical outcome scores were analyzed in this study as a proxy to assess subscapularis function, ASES and WOOS. While there were no significant differences in ASES scores between all three approaches in subscapularis management, there was a significantly greater WOOS index in both the LTO and SP groups when compared with ST. The WOOS index measures function and quality of life, as reported by patients with glenohumeral osteoarthritis, and WOOS has been shown to be reliable and valid in this population. ¹³ Previous studies have found the specificity of WOOS to allow for improved ability to detect smaller clinical differences before and after treatment when compared with more generic outcome measures. ⁴⁹ While we did find a statically significant difference in WOOS indices, it is important to note that the minimum clinically important difference has not been determined for the WOOS. ¹⁵ It is plausible that this difference might be clinically relevant given that LTO and SP improved WOOS scores by 8.4 and 6.8 points compared to ST, respectively.

In terms of motion and strength, this meta-analysis showed some advantages of LTO and SP over ST. First, when assessing internal rotation strength, we found that both LTO and SP had improved strength when compared to ST, however, it is important to note that potential confounders for internal rotation strength were unable to be controlled for in this analysis. In terms of motion, our meta-analysis showed that SP had superior external rotation compared to LTO while no difference was observed between SP and ST or between ST and LTO. These findings are corroborated by other reviews suggesting that LTO and SP may confer similar outcomes that are superior to ST; ⁵⁰ however, there is a limited number of high-quality studies to validate whether one technique is clearly advantageous over another for the preservation of motion and strength. ⁵¹ For example, among the six studies that were grouped to analyze external rotation, only one was a randomized control trial while the rest were retrospective cohort trials.

Strengths and limitations

In comparison to prior meta-analyses, this study provided the largest number of studies on subscapularis management in aTSA thus far. A total of 23 studies were included with 10 being comparative and 13 non-comparatives. The latest meta-analysis has not found a statistical difference in ROM between all three subscapularis techniques, and no functional scores were compared due to sample size limitations. ¹⁵ The inclusion of 3 additional comparative studies in our network meta-analysis increased the sample size and permitted the comparison of ASES and WOOS scores. Second, our network meta-analytic comparison resulted in statistically significant improvement in WOOS scores and ER ROM for LTO and SP compared to ST. Thus, the main strengths of our network meta-analysis were performing a meta-analytic comparison for functional outcomes and having different results compared to prior meta-analyses. In addition, the inclusion of non-comparative studies allowed the calculation of weighted averages for subscapularis healing and LTO union rates. In turn, this would provide shoulder surgeons with a comprehensive summary of the literature on this topic.

There are limitations to this study. As with all meta-analyses, methodologic heterogeneity between studies can be a potential source of error. There were multiple methods of repairing the subscapularis within each group in our study; for example: different techniques include side-to-side suturing, transosseous suturing, suture incorporation to the humeral stem, and augmentation with a plate or button. ¹⁵ Grouping all repairs into three groups may be prone to additional error. Further, additional nuances could not be accounted for, such as LTO size which could potentially affect union rates. Another possible cofounder is the inclusion of some studies analyzing hemiarthroplasty, which has been shown to have less improvement in pain when compared with TSA.^52,53 However, these potential limitations are counteracted by the greater statistical rigor as well as external generalizability to the greater population of meta-analyses.

In conclusion, this network meta-analysis demonstrated that LTO and SP may lead to significantly improved shoulder function and quality of life when compared to ST. Moreover, LTO and SP were associated with the high union and subscapularis healing rates compared to ST. These results suggest that LTO and SP demonstrate a trend of superior outcomes compared to ST during aTSA. It is important to highlight that most of the current evidence on subscapularis management in aTSA is low and is derived from level III and IV studies. Therefore, further multicenter randomized studies are warranted to ascertain which subscapularis management technique leads to superior outcomes. This can be performed by focusing on several validated shoulder outcome measures and advanced imaging for investigating subscapularis healing.