Outcomes of lateralized reverse total shoulder arthroplasty versus latissimus dorsi transfer for external rotation deficit: a systematic review and meta-analysis

Article information

Clin Shoulder Elb. 2024;27(4):464-478

Publication date (electronic) : 2024 November 15

doi : https://doi.org/10.5397/cise.2024.00304

Keegan M. Hones¹, Caroline T. Gutowski², Taylor R. Rakauskas³, Victoria E. Bindi⁴, Trevor Simcox¹, Jonathan O. Wright¹, Bradley S. Schoch⁵, Thomas W. Wright¹, Jean-David Werthel⁶, Joseph J. King^,1, Kevin A. Hao¹

¹Department of Orthopaedic Surgery and Sports Medicine, University of Florida, Gainesville, FL, USA

²Cooper Medical School, Rowan University, Camden, NJ, USA

³College of Medicine, Florida Atlantic University, Boca Raton, FL, USA

⁴College of Medicine, University of Florida, Gainesville, FL, USA

⁵Department of Orthopaedic Surgery, Mayo Clinic, Jacksonville, FL, USA

⁶Department of Orthopedic Surgery, Hospital Ambroise Paré, Boulogne-Billancourt, France

Corresponding Author: Joseph J. King Department of Orthopaedic Surgery and Sports Medicine, University of Florida, 3450 Hull Rd, Gainesville, FL 32611, USA Tel: +1-352-273-7002 Fax: +1-352-273-7293 Email: kingjj@ortho.ufl.edu

Received 2024 April 10; Revised 2024 July 1; Accepted 2024 July 29.

Abstract

INTRODUCTION

Reverse shoulder arthroplasty (RSA) is the most reliable surgical treatment for patients with cuff tear arthropathy and irreparable rotator cuff tears with pseudoparalysis [1]. Increased mechanical advantage of the deltoid muscle provided by RSA improves overhead shoulder elevation in posterosuperior rotator cuff tears, but is limited in reconstituting external rotation (ER) deficits [2-6]. Thus, patients with combined loss of active elevation and external rotation (CLEER) as a result of a compromised posterosuperior rotator cuff may not fully recover function with RSA alone [4]. Past studies using the Grammont style prosthesis with a 155° neck-shaft angle showed little to no improvement in ER following RSA in patients with CLEER [7,8].

Latissimus dorsi transfer (LDT) combined with RSA has been utilized to improve functional outcomes in patients with CLEER deficits with reliable results [3,4,9-14]. However, LDT has several downsides including greater surgical complexity, risk of nerve injury, and theoretical loss of internal rotation. While LDT is still frequently performed, some surgeons contend that modern lateralized RSA (relative to the original Grammont design, with a glenoid lateral offset [LO] ≥5 mm and/or a humeral LO ≥5 mm of the Delta III) [15] alone is sufficient to restore ER in patients with preoperative insufficiency through tensioning of the remaining posterior rotator cuff and deltoid [16-20]. However, only a limited number of studies have compared restoration of ER in patients with preoperative insufficiency after RSA with LDT versus lateralized RSA alone.

The goal of this systematic review and meta-analysis was to compare clinical outcomes and complication rates following RSA with LDT versus lateralized RSA alone in patients with preoperative ER deficiency. We hypothesized that greater improvement in postoperative range of motion (ROM) would be observed following LDT with RSA, with similar patient-reported outcome scores to RSA alone.  

METHODS

No institutional review board approval was obtained, given that the review did not involve experimentation on human or animal subjects, and the data reviewed are public. This systematic review was performed in accordance with the guidelines for Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) [21].

Eligibility Criteria

We included original studies written in English and published prior to January 2023 evaluating the use of RSA with LDT or lateralized RSA alone in patients with ≤0° of active ER with the shoulder adducted to the side [22]. We excluded duplicate studies, non-English text, reviews and meta-analyses, commentaries and editorials, purely radiographic studies, studies that solely evaluated surgical technique, non-human studies, biomechanical studies or those without clinical variables, studies in which greater than 10% of the cases included were post-traumatic, allograft-prosthetic composite reconstruction or tumor cases, and those in which the patient population had preoperative deltoid dysfunction or axillary nerve palsy. To maximize inclusion, functional outcomes and the incidence of postoperative complications were assessed independently (Fig. 1). Thus, studies reporting only functional outcomes or only complications were included.

Fig. 1.

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram depicting article identification, subsequent exclusion, and analysis for clinical outcomes and complications. RSA: reverse total shoulder arthroplasty, LDT: latissimus dorsi tendon transfer, ER: external rotation.

RESULTS

RSA with LDT vs. Lateralized RSA Alone

In the RSA with LDT cohort, the weighted mean preoperative ER was –14° (range, –42° to 0°) and 22° postoperatively (range, 10°–39°), while FE was 70° preoperatively (range, 59°–116°) and 140° postoperatively (range, 123°–163°). The weighted mean postoperative Constant score was 65 (range, 59–72). There were 148 patients among nine studies with postoperative IR reported (Table 1). Thirty-four percent of included patients reported a mean IR that achieved the MNIR (i.e., L3 vertebral level). In the lateralized RSA cohort, the mean ER was –11° preoperatively (range, –18° to 0°) and 27° postoperatively (range, 25°–32°), FE was 76° preoperatively (range, 53°–83°) and 140° postoperatively (range, 137°–149°). The mean postoperative Constant score was 70 (range, 67–71). There were 250 patients among four cohorts with postoperative IR reported. Four percent of included patients reported a mean IR that achieved the MNIR.

Table 1.

Studies reporting mean postoperative internal rotation after reverse shoulder arthroplasty utilizing latissimus dorsi transfer vs. not and a globally lateralized vs. medialized implant design

Meta-analysis revealed significantly greater postoperative ER after lateralized RSA alone compared to RSA with LDT (28° [25°–32°] vs. 22° [19°–26°], P=0.010) (Fig. 2A). However, pre- to postoperative improvement in ER was identical after lateralized RSA alone and RSA with LDT (37° [32°–43°] for both, P=0.985) (Fig. 2B). When controlling for mean preoperative ER and percentage of patients with subscapularis repair using multivariable meta-regression, RSA with LDT was associated with poorer postoperative ER (β=–6.2 [–10.8 to –1.6], P=0.014) but not pre- to postoperative improvement in ER (P=0.230) (Table 2). Meta-analysis revealed no difference in postoperative FE or pre- to postoperative improvement in FE (Fig. 3). However, lateralized RSA alone had a more favorable postoperative Constant score compared to RSA with LDT (69 [67–72] vs. 65 [62–67], P=0.014) (Fig. 4).

Fig. 2.

(A) Postoperative external rotation (ER): lateralized reverse shoulder arthroplasty (RSA) alone vs. RSA with latissimus dorsi transfer (LDT). (B) Pre- to postoperative improvement in ER: lateralized RSA alone vs. RSA with LDT. SD: standard deviation, MD: mean difference.

Table 2.

Multivariable meta-regression performed to compare lateralized RSA alone vs. RSA with LDT for postoperative ER and pre- to postoperative improvement in ER independent of the mean preoperative ER and the percentage of patients with subscapularis repair

Fig. 3.

(A) Postoperative forward elevation (FE): lateralized reverse shoulder arthroplasty (RSA) alone vs. RSA with latissimus dorsi transfer (LDT). (B) Pre- to postoperative improvement in FE: lateralized RSA alone vs. RSA with LDT. SD: standard deviation, MD: mean difference.

Fig. 4.

Postoperative Constant score: lateralized RSA alone vs. reverse shoulder arthroplasty (RSA) with latissimus dorsi transfer (LDT). SD: standard deviation.

Sub-analysis: RSA with LDT Based on Implant Lateralization

Sub-analysis revealed that postoperative ER differed between lateralized RSA alone and RSA with LDT using medialized and lateralized implants (28° [25°–32°] vs. 23° [20°–25°] vs. 21° [15°–27°], P=0.014) (Fig. 5), but there was no difference in pre- to postoperative improvement in ER (P=0.525). Multivariable meta-regression demonstrated less favorable postoperative ER for lateralized RSA with LDT compared to lateralized RSA alone (β=–6.9 [–12.6 to –1.2], P=0.023) (Table 3). Sub-analysis revealed no difference in postoperative FE or pre- to postoperative improvement in FE (Fig. 6). Postoperative Constant score was greatest for lateralized RSA alone, followed by medialized and lateralized RSA with LDT (69 [67–72] vs. 67 [63–70] vs. 63 [60–67], P=0.038) (Fig. 7).

Fig. 5.

(A) Postoperative external rotation (ER): lateralized reverse shoulder arthroplasty (RSA) alone vs. RSA with latissimus dorsi transfer (LDT) vs. medialized RSA with LDT. (B) Pre- to postoperative improvement in ER: lateralized RSA alone vs. lateralized RSA with LDT vs. medialized RSA with LDT. SD: standard deviation.

Table 3.

Multivariable meta-regression performed to compare lateralized RSA alone vs. medialized RSA with LDT vs. lateralized RSA with LDT on postoperative ER and pre- to postoperative improvement in ER independent of mean preoperative ER and the percentage of patients with subscapularis repair

Fig. 6.

(A) Postoperative forward elevation (FE): lateralized reverse shoulder arthroplasty (RSA) alone vs. lateralized RSA with latissimus dorsi transfer (LDT) vs. medialized RSA with LDT. (B) Pre- to postoperative improvement in FE: lateralized RSA alone vs. lateralized RSA with LDT vs. medialized RSA with LDT. SD: standard deviation.

Fig. 7.

Postoperative Constant score: lateralized reverse shoulder arthroplasty (RSA) alone vs. lateralized RSA with latissimus dorsi transfer (LDT) vs. medialized RSA with LDT. SD: standard deviation.

DISCUSSION

In this systematic review and meta-analysis, we demonstrated that both lateralized RSA alone and RSA with LDT can restore ROM in ER and FE and yield satisfactory Constant scores in patients with preoperative ER deficits. Patients who underwent lateralized RSA alone had superior postoperative ER and Constant scores compared to RSA with LDT, but there was no difference in postoperative FE. However, there was no difference in pre- to postoperative improvement for ER or FE. The use of a medialized versus lateralized RSA with concomitant LDT did not appear to influence outcomes. In patients who received an LDT, our meta-analysis suggested that the rate of tendon transfer tear was 2.1%, that of nerve-related complications was 2.1% (vs. 0%), and dislocation rate was 2.8% (vs. 0.8%).

Whether patients with preoperative deficits in ER (often in the setting of CLEER) undergoing RSA require concomitant LDT to attain sufficient ER is contentiously debated. Favre et al. [37] demonstrated in vitro that the posterior deltoid moment arm after RSA implantation is biomechanically inadequate to achieve active ER. Consequently, for patients with a deficient posterior rotator cuff, many surgeons believe lateralized RSA alone is insufficient to achieve satisfactory active ER. Boileau et al. [36] initially found that RSA with LDT provided sufficient torque for ER in patients with deficient infraspinatus and teres minor muscles, but this finding was challenged by Berglund et al., [38] who reviewed 33 lateralized RSAs in patients with preoperative active ER <0° and at least two years follow-up, finding no relationship between teres minor atrophy and the restoration of ER.

Prior studies attempted to evaluate whether LDT confers a benefit to RSA alone using modern techniques, but failed to account for the influence of implant design [22,35]. Young et al. [35] performed a randomized controlled trial of 28 patients with cuff tear arthropathy and CLEER pathology who received RSA alone or in combination with a LDT. At 2-year follow-up, no differences were found between RSA with LDT and RSA alone with regard to active ER, IR, FE, and patient-reported outcome scores. However, only 12 of 28 patients were assessed for postoperative ER at 2-year follow-up. Furthermore, Young et al. [35] utilized two different implant systems: the Zimmer Trabecular Metal Reverse Shoulder System and Biomet Comprehensive Reverse Arthroplasty System (Zimmer Biomet). According to the classification system published by Werthel et al. [15], the former is ML and the latter is HL. Loss to follow-up or confounding due to utilization of heterogeneous implant designs may have obscured the influence of the LDT on postoperative ER.

Wiater et al. [22] retrospectively evaluated 31 patients who underwent RSA with LDT and compared them to 33 patients that underwent RSA alone. Both cohorts were similar preoperatively except for marginally poorer active ER in the RSA with LDT group (−8° vs. 0°, P=0.004). Postoperatively, ER was similar between RSA with and without LDT (14°±13° vs. 17°±15°, P=0.43). Regarding implant utilization, patients in the RSA with LDT group received a Zimmer trabecular metal reverse humeral stem (Zimmer) with either a Zimmer reverse glenosphere/baseplate (n=23) or a DJO Encore reverse glenosphere/baseplate. All patients in the RSA alone group received a Zimmer reverse humeral stem and glenosphere/baseplate, which is an ML design per Werthel et al. [15] It is unclear from these data whether use of a lateralized RSA design in the cohort of RSAs without LDT would have resulted in the maintenance of superior ER postoperatively.

Although we attempted to design a fair comparison between RSA with LDT and lateralized RSA alone cohorts by requiring the mean preoperative ER of included studies to be ≤0°, the preoperative mean ER in the RSA with LDT cohorts was lower than the lateralized RSA alone cohort (–14° vs. –11°). This represents selection bias present in the literature and may indicate surgeon preferences to reserve LDT for patients with CLEER pathology and severe ER. After accounting for the mean preoperative ER of included studies in our meta-regression analysis, we found no effect on pre- to postoperative improvement in ER based on whether RSA with LDT or lateralized RSA alone was performed. Although this result suggests that lateralized RSA alone may be sufficient for patient populations with very poor preoperative ER, meta-regression analyses are limited by the range of included data. Therefore, we encourage readers to interpret these findings cautiously, and we advocate for either a case-matched cohort study or prospective trial to definitively determine whether lateralized RSA alone is sufficient to restore ER in deficient patients.

We also found no difference in outcomes when comparing lateralized RSA and LDT with varying prosthesis design. Although prior studies have suggested lateralization alone may restore ER [39,40], these studies were not exclusively comprised of patients with preoperative CLEER or active ER ≤0°. Lateralized designs have been purported to increase ER by improving the length-tension of the rotator cuff, increasing the deltoid wrap, and optimizing the deltoid moment arm [41-44]. Berton et al. [45] in their systematic review of 24 studies and meta-analysis of 19 studies, found significantly greater postoperative ER in lateralized compared to medialized RSA (20.4° and 8.3°, respectively). While lateralization alone may be sufficient in many patients to restore active ER, patients who lack a posterior rotator cuff may receive less benefit and require LDT for functionally successful outcomes. Although Berglund et al. [38] found no association between status of the posterior rotator cuff and restoration of ER using a lateralized design, future studies are needed to corroborate this finding.

Another factor to consider is that TMT is often performed concomitantly with LDT, and our RSA with LDT cohort was comprised of both patients with and without TMT. Many authors have demonstrated that concomitant TMT with LDT plays an important role in ER strength after RSA [8,37]. However, Hones et al. [46] conducted a systematic review and meta-analysis of 19 studies and found no significant differences in ER or Constant score when comparing patients who underwent RSA with LDT alone versus LDT with TMT.

When deciding whether to perform an LDT, surgeons must consider that active ER improvement may come at the cost of higher complication rates. While reported complication rates for primary RSA vary, the overall complication rate is commonly quoted to be approximately 15% [47,48]. Hones et al. [46] reported a complication rate of 14% in their systematic review and meta-analysis of RSA with LDT, and Puskas et al. [5] reported a 22% orthopedic complication rate in their series of 41 RSAs with LDT. There is a higher risk of nerve injury with LDT given the necessary dissection for safe release and transfer of the tendon. Currently available studies of RSA with LDT report the incidence of transient nerve palsy to be 3.1%– 3.4% [46,49], which is markedly higher than that of primary RSA, which has been shown to be about 1.3% [50]. In our analysis, none of the included lateralized RSA alone cohorts reported a postoperative nerve injury.

Another consideration when planning LDT is prosthesis dislocation. We observed a dislocation rate of 2.8% in patients receiving an LDT and 0.8% in lateralized RSA alone. While the higher dislocation rate could be related to the LDT in that cohort, the inclusion of studies that utilized a medialized design may also be responsible. Dislocation rates of primary RSA without tendon transfer have generally ranged from 2% to 5% in the recent literature [51-53]. Subscapularis repair may increase the anterior stability of the RSA and decrease the dislocation rate [54,55]. All RSA with LDT cohorts included in the present study underwent routine subscapularis repair. While operative time and blood loss is not routinely reported in the literature and we therefore did not attempt to evaluate it, longer operative time and greater blood loss are both theoretical downsides of RSA with LDT due to additional tendon harvest. Unique to LDT, we reported a humeral cortical erosion rate of 19%. This may reflect length of follow-up, as Bonnevialle et al. [2] reported an osteolysis rate of 77% after L’Episcopo transfer in 13 patients at a mean of 37 months postoperatively, with osteolysis appearing to worsen over time. However, there was no ultimate impact on clinical outcomes in their series. Furthermore, Valenti et al. [33] evaluated 24 RSAs with LDT at a mean follow-up of 45 months and found that eight (33%) patients demonstrated intact lateral cortex, eight (33%) irregular and eight (33%) lytic lesions, with no differences in clinical outcomes between patients with and without bony lesions.

This systematic review and meta-analysis has several limitations. Limitations include those inherent to all reviews, i.e., the analysis of many retrospective studies with possible individual, compounded reporting bias and the quality of the review being dictated by the quality of the individual studies. Moreover, the included studies had varying follow-up periods. We were unable to statistically analyze IR due to heterogeneity in reporting, which remains an important limitation in comparisons of these procedures, as loss of the latissimus dorsi with or without the teres major as internal rotators is a consideration. While implants were classified according to the Werthel et al. [15] global lateralization classification, modularity of implants may also influence lateralization of the center of rotation [56]. While it is important to attempt to make a fair comparison between groups, the relative rarity of preoperative active ER ≤0° in patients undergoing RSA limited the sample size significantly, and larger populations are necessary to draw stronger conclusions. Furthermore, our cohorts did not have equivalent preoperative ER despite our efforts, which further limits our conclusions. Although we performed a multivariable meta-regression analysis to attempt to control for unequal preoperative ER, our results should be interpreted with caution. We queried highly utilized databases with broad search terms and no time limitation, nevertheless, relevant articles may have been missed. We also did not set a minimum level of evidence as an inclusion criterion given that the majority of studies of RSA with LDT were anticipated to be small retrospective case series.

CONCLUSIONS

Both RSA with LDT and lateralized RSA are reliable options to restore ER in patients with significantly limited preoperative ER. In our meta-analysis and meta-regression, lateralized RS alone was associated with superior postoperative ER and Constant score compared to RSA with LDT, but similar postoperative FE with no differences in pre- to postoperative improvement in ER or FE. Compared with lateralized RSA alone, addition of LDT comes with increased complication risks, namely with regard to nerve injury and dislocation. Overall, addition of an LDT may be necessary in certain patient populations, but our results suggest that lateralized RSA alone can be sufficient to restore ER. Future comparative studies are needed to further ascertain the role of LDT in treating patients with severe ER deficiency indicated for RSA.

SUPPLEMENTARY MATERIALS

Article information Continued