Surgical technique for secondary pectoralis major transfer after reverse total shoulder arthroplasty to treat residual internal rotation dysfunction
Article information
Abstract
Reverse total shoulder arthroplasty (RSA) has emerged as a promising treatment option for rotator cuff tear arthropathy. However, concerns persist regarding horizontal rotational dysfunction after RSA. While many studies focus on improving external rotation after RSA, limited attention has been paid to internal rotation. In this technical note, we describe how to perform secondary pectoralis major transfer in a patient with residual internal rotation dysfunction after RSA.
The necessity of repairing the subscapularis in the setting of reverse total shoulder arthroplasty (RSA) remains a subject of ongoing debate. However, limited improvement in internal rotation (IR) after RSA can significantly impact the ability of patients to perform essential daily activities, such as toileting, which is a key factor in overall patient satisfaction [1,2]. IR is also crucial for tasks like eating, dressing, washing, hair brushing, and maintaining personal hygiene, all of which profoundly affect patient outcomes and satisfaction [1,3]. Collin et al. [4] found that patients with healed subscapularis tendons tended to exhibit better IR than those with ruptured and subsequently repaired subscapularis tendons after undergoing RSA with a lateralized glenoid prosthesis. As a result, they recommended repairing the subscapularis tendon whenever feasible during RSA. In cases where the subscapularis is irreparable, alternative treatment strategies may be required to restore IR. For instance, Kany [5] suggested RSA combined with anterior latissimus dorsi (LD) transfer for patients who experience both loss of elevation and IR. Similarly, Baek et al. [6] proposed the combination of RSA with anterior LD and teres major (TM) transfer to enhance the range of motion (ROM) and strength of IR.
Resolving horizontal rotational deficiencies in RSA proves to be a complex challenge [7,8]. Puskas et al. [9] reported that secondary posterior LD transfer can significantly improve active external rotation (ER) in patients experiencing residual ER dysfunction after RSA. While there has been considerable focus on addressing ER issues post-RSA [10-12], there have been limited reports on managing residual IR dysfunction after the procedure. IR dysfunction after RSA can be attributed to either retear of the repaired subscapularis or irreparability of the subscapularis during the primary RSA procedure. As pectoralis major (PM) transfer has been recognized for its ability to improve IR [13], some clinical studies [14,15] have highlighted its combination with RSA in single-stage surgery [15,16]. Despite the significant impact that IR dysfunction after RSA can have on a patient's ability to perform daily activities requiring IR [1,2], no reports have specifically addressed the use of secondary PM transfer to address residual IR dysfunction after RSA. In this technical report, we present a surgical technique for secondary PM transfer in patients who experience residual IR dysfunction after RSA. As this study does not involve clinical outcomes, informed consent was not applicable. Furthermore, as a technical note, it was exempt from requiring approval by the institutional review board.
TECHNIQUE
Indications and Contraindications
Indications
(1) Failed subscapularis repair after primary RSA or irreparable subscapularis. (2) Patient complaints of IR dysfunction after RSA, evidenced by the decreased ability to perform daily activities requiring IR or reduced IR strength measured with a standard dynamometer. (3) No signs of loosening of the RSA. (4) Adequate bone stock in the greater tuberosity confirmed by x-ray or computed tomography (CT) scan without resorption. (5) Patient willingness to restore IR dysfunction.
Contraindications
(1) Postoperative stiffness in RSA with severely limited ROM. (2) Inadequate bone stock in the greater tuberosity due to resorption. (3) Any nerve-related problems specifically involving the medial and lateral pectoral nerves. (4) A previous history of postoperative infection after RSA. (5) Any signs of loosening of the RSA.
Surgical Technique
The entire surgical procedure is illustrated in Supplementary Video 1.
Approach and check status of subscapularis and prosthesis
The patient is placed in the beach-chair position and administered general anesthesia. Using the previous incision line of the primary RSA, a standard deltopectoral approach is performed, with the incision extended inferiorly to the inferior border of the PM muscle (Fig. 1). Using a reduction tool to carefully dislocate the shoulder, surgeons assess the status of both the subscapularis and the prosthesis (Fig. 2). During this critical step, surgeons carefully examine the joint for signs of prosthesis loosening and assess the reparability of the subscapularis. If the subscapularis is found to be irreparable, the surgical procedure may proceed to PM transfer.
Skin marking and approach. (A) The skin is marked along the previous incision line (white arrow) of the deltopectoral approach and the palpable border of the pectoralis major muscle (red arrows). (B) Following the standard deltopectoral approach, the pectoralis major muscle (white asterisk) is identified with the deltoid retracted laterally.
Assessing the stability of the implant and reparability of the subscapularis. (A) Using a retractor tool (white arrow), (B) the shoulder is dislocated to examine the stability of the implant (white asterisk) and the reparability of the subscapularis (white arrows: the remnant of suture material, signifying the retear of the previously repaired subscapularis from the primary reverse total shoulder arthroplasty).
Preparing PM transfer
To harvest the PM, both the superior and inferior borders of the PM muscle are meticulously released from the surrounding soft tissue. Subsequently, the entire PM, without separating the clavicular and sternal heads, is detached from its humeral insertion site. With help of two long forceps, both the superior and lower edges of the detached PM are secured with two #2 sutures with needle (Genesys CrossFT, ConMed Linvatec) in a continuous locking fashion (Fig. 3).
Pectoralis major preparation. (A) Pectoralis major (white asterisk) is detached from its insertion site on the humerus and secured with two long forceps (white arrows). (B) Non-absorbable #2 sutures (white arrows) are placed on each edge of the pectoralis major (white asterisk) in a continuous locking fashion.
During suture placement, special attention is given to incorporating the thick and deep tendinous portion of the undersurface area near the insertion site of PM. This approach enhances suture retention and prevents subsequent retear. Given that this is a secondary procedure, meticulous care should be exercised in consideration of the anatomical structures, and caution should be applied during dissection due to postoperative adhesions.
Bone drilling and humeral side preparation
Using a marker, first a temporary guideline is drawn, extending from the upper edge of the bicipital groove to the upper edge of the teres minor insertional site in the greater tuberosity (Fig. 4A). Another temporary guideline, positioned approximately 1.5 cm inferior and parallel to the initial one, is then drawn. Subsequently, a drill bit loaded with a 2.0-mm K-wire is used, following the temporary guidelines, to create a tunnel for the transosseous suture (Fig. 4B). For each superior and inferior tunnel, transosseous sutures using #2 suture (Permacord Suture, DePuy Mitek) are shuttled and passed through each tunnel in a loop fashion using a spinal needle loaded with a loop wire (Fig. 5). Each suture is individually tied and locked with a sliding locking knot strategically placed in the posterior part of the tunnel.
Creating tunnels for transosseous sutures. (A) A temporary guideline (white arrowheads) is drawn, extending from the upper edge of the bicipital groove (yellow arrow) to the upper edge of the teres minor insertion site (blue arrow) in the greater tuberosity. Another temporary guideline (white arrowheads), positioned approximately 1.5 cm inferior and parallel to the first temporary guideline, is also drawn. (B) Then, 2.0 mm K-wires (blue arrows) are placed along the temporary guidelines (white arrowheads).
Shuttling sutures. (A) Using a spinal needle (white arrow) loaded with a loop wire (red arrow), (B) non-absorbable #2 transosseous sutures (white arrow: upper tunnel, red arrow: lower tunnel) are passed through each tunnel in a loop fashion.
Emphasizing the importance of precision, it is crucial when creating a tunnel with a drill bit to ensure that it is not superficial but is deeply placed in the greater tuberosity to avoid potential bone cracks. Furthermore, the transosseous sutures are securely tied in a locking fashion. This not only prevents sliding of the sutures within the bone but also ensures a robust and secure attachment of the PM transfer.
Attachment of PM to humerus
Using a spinal needle with loop wire, one of the suture limbs in the superior part of harvested PM is shuttled through the upper tunnel. The same procedure is replicated for the lower tunnel (Fig. 6A). One of the upper transosseous suture limbs is threaded in the upper edge of the harvested PM. The same procedure is replicated for the lower tunnel. For the initial fixation, the patient's arm is positioned in full IR. Subsequently, the harvested PM sutures and the transosseous sutures are tied separately (Fig. 6B). To enhance stability of attachment between the harvested PM and he humerus, one of the suture limbs of the harvested PM in the upper tunnel is threaded along the upper edge of the PM using continuous locking sutures (Fig. 7A). This suture limb is then tied with the suture limbs of the transosseous suture. The same process is performed for the lower tunnel (Fig. 7B). These additional continuous locking sutures reinforce the strong attachment of the harvested PM to the greater tuberosity of the humerus.
Initial fixation of harvested pectoralis major to the greater tuberosity of humerus. (A) Each suture limb (blue arrow) of the harvested pectoralis major (white asterisk) is passed through the corresponding tunnel. Both transosseous suture limbs (yellow arrow: upper tunnel, white arrow: lower tunnel) and the harvested pectoralis major suture limbs (blue arrow) are shown. (B) One suture limb of the transosseous suture (yellow arrow: upper tunnel, white arrow: lower tunnel) is threaded through the pectoralis major (white asterisk), and the transosseous suture of each tunnel is tied separately. Harvested pectoralis major suture limbs (blue arrows) are tied separately.
Attachment reinforcement. (A) One of the harvested pectoralis major suture limbs (yellow arrow) in the upper tunnel is threaded along upper edge of the pectoralis major (white asterisk) in continuous locking sutures. (B) The identical process is applied to the lower tunnel (white arrow: one of harvested pectoralis major suture limbs, white asterisk: pectoralis major).
Surgeons should ensure that continuous locking sutures are horizontally applied along the upper and lower borders of the PM, avoiding vertical application, as this could pose a risk of tearing at the insertional site. It is also important to avoid placing continuous locking sutures too medially to prevent damage to the muscular portion of the PM, instead applying them near the insertional site where there is more tendinous tissue. Following the final attachment (Fig. 8), the arm should be rotated to check for any impingement.
Final appearance. Final appearance of secondary pectoralis major transfer (white asterisk) to the greater tuberosity of the humerus (yellow asterisk).
Postoperative Care
In the initial postoperative 4 weeks, the patient is required to wear an abduction brace, but is allowed intermittent movement for daily tasks. After 4 weeks the brace is removed, and active-assisted ROM exercises begin. By the third month, the patient will progress to strengthening exercises. However, heavy labor and sports are prohibited until the sixth postoperative month, emphasizing a cautious approach to protect healing tissues.
DISCUSSION
Limitations in improvement of IR after RSA can greatly hinder a patient’s ability to perform critical daily tasks, such eating, dressing, washing, hair brushing, and maintaining personal hygiene, which are essential for their overall satisfaction [1,2]. Whether or not to repair the subscapularis during RSA is debated. PM transfer is recognized for its potential to enhance IR [13], and several case reports have documented its use in combination with RSA during single-stage surgery [14-16].
In this technical note, we outline a procedure for performing secondary PM transfer in patients who experience residual IR dysfunction after RSA. PM transfer offers several biomechanical advantages compared to anterior LD with or without TM transfer. A biomechanical study by Werthel et al. [17] compared the IR moment arm among various forms of tendon transfer, including LD, TM, and PM transfers, both with and without RSA. They found that PM tendon transfer provided the greatest IR moment arm. Additionally, Chan et al. [18] demonstrated the effectiveness of PM tendon transfer in restoring IR in lateralized RSA, noting that as humeral component lateralization increased, the IR torque of the PM tendon either increased or remained stable. Despite these promising results, the scarcity of clinical studies on RSA combined with PM transfer highlights the need for further clinical validation.
PM transfers encompass harvesting the entire PM or selectively harvesting either the clavicular or the sternal head [19,20]. While biomechanical study [21] suggests the superiority of the sternal head in restoring IR, we chose to transfer the entire PM to augment the transferred muscle's volume mass to maximize the effect on IR. We posit that increased transfer muscle volume contributes to enhanced IR improvement. This perspective aligns with previous characterizations of the clavicular and sternal heads as two distinct, independently functioning components, each endowed with its own neurovascular supply [19,22,23]. Biomechanically, the anterior and superior stability of the glenohumeral joint demonstrated restoration to values closer to those of the intact shoulder when the PM was routed underneath, rather than above, the conjoint tendon [21,23]. However, we chose to transfer the PM above the conjoint tendon, as placing the entire bulky PM muscle beneath the conjoint tendon could impinge on the musculocutaneous nerve, given its anatomical variability in its location [24].
Numerous studies focus on transferring the PM to the lesser tuberosity to address irreparable subscapularis tear [20]. However, our technique differs by transferring the PM to the greater tuberosity, aligning with a technique previously described by Wirth and Rockwood et al. [25] transferring the PM to the greater tuberosity offers advantages due to its larger bony volume, potentially improving IR through better muscle tensioning. To preserve bone stock, we chose transosseous suture fixation over anchors or other methods, as it is more effective for conservation.
Our technique is not without limitations. Notably, proximal bone resorption, recognized as humeral stress shielding, may be encountered, particularly following primary RSA with press-fit humeral stems [26]. In such cases, our technique may not be suitable. Additionally, patients with osteoporosis may not be ideal candidates, as osteoporotic bone may lack the strength required to support the attachment of the transferred PM to the greater tuberosity. Lastly, there has been limited study regarding the clinical outcomes of combining PM transfer and RSA [21,24]. However, our technique is straightforward, easily replicable, and avoids the need to remove the implanted prosthesis.
In this technical report, we discuss each step of a novel procedure for secondary PM transfer in patients with residual IR dysfunction after RSA. While this surgical technique may not be suitable for patients with greater tuberosity resorption, it is relatively easy and straightforward, as we perform PM transfer without removing the implanted RSA. The technique offers significant biomechanical advantages over other forms of tendon transfer, particularly for restoring IR strength and function, which are critical to preserve patients' abilities to perform essential daily activities.
Notes
Author contributions
Conceptualization: CHB, BTK, JGK. Data curation: CHB. Investigation: BTK, JGK. Methodology: CHB, BTK, JGK. Project administration: CHB. Supervision: CHB, BTK. Validation: CHB, BTK, JGK. Visualization: CHB, BTK, JGK. Writing – original draft: CHB, BTK. Writing – review & editing: all authors. All authors read and agreed to the published version of the manuscript.
Conflict of interest
None.
Funding
None.
Data availability
None.
Acknowledgments
The authors would like to express special thanks to Yeong Ran Seo, Hyun Mi Kim, Seung Hwan Oh, and Seul Gi Yun for their assistance.
SUPPLEMENTARY MATERIALS
Supplementary materials can be found via https://doi.org/10.5397/cise.2024.00542.
The video illustrates the entire surgical procedure for secondary pectoralis major transfer following reverse total shoulder arthroplasty. The surgery was performed in a beach chair under general anesthesia. The surgery was performed on the right shoulder.