Lower trapezius tendon transfer for posterior–superior irreparable rotator cuff tears: a comprehensive narrative review

Abstract

Lower trapezius tendon (LTT) transfer has emerged as an effective surgical treatment for posterior–superior irreparable rotator cuff tears (PSIRCTs), particularly in patients with compromised external rotation.²³ Initially used in paralytic shoulders,^12,18,22 LTT has gained popularity as a treatment option for irreparable rotator cuff tears due to its biomechanical similarity to the infraspinatus, making it an effective choice for restoring shoulder function.^11,32,34 LTT's ability to re-establish shoulder stability, restore external rotation, and prevent humeral head migration sets it apart from other tendon transfers like latissimus dorsi transfer.³³ The procedure can be performed using an arthroscopically assisted technique, reducing invasiveness and preserving soft tissue.²¹ LTT is indicated for patients with PSIRCTs who have significant shoulder dysfunction, failed conservative treatments, and minimal glenohumeral arthritis. However, it is contraindicated in cases of advanced osteoarthritis. Clinical studies have shown improved range of motion, pain relief, and functional outcomes post-operatively.^{6,7,14,15,21,23,35,43} Comparative studies also suggest superior results with LTT over latissimus dorsi transfers and superior capsular reconstruction.^8,10 As interest in joint-preserving procedures grows, LTT's role continues to expand, with refinements in surgical techniques and emerging innovations, such as the “parachute technique” and biologic augmentation, enhancing its efficacy.²⁰ This review examines LTT's biomechanics, clinical outcomes, comparative studies, and evolving innovations, highlighting its potential as a primary and salvage procedure for PSIRCTs.

Lower trapezius tendon (LTT) transfer has emerged as a valuable surgical intervention for patients, particularly with posterior–superior irreparable rotator cuff tears (PSIRCTs).²³ This type of tear presents a significant clinical challenge, often leading to persistent pain, functional impairment, and external rotation deficits that severely impact a patient's quality of life. Over the years, various surgical techniques have been developed to address these tears, with LTT transfer gaining increasing attention as a reliable and effective option. Originally, LTT transfer was primarily used to restore shoulder function in individuals with paralytic shoulders caused by brachial plexus injuries.^12,18,22 In cases of nerve-related paralysis, the lower trapezius remains functional due to its innervation by the spinal accessory nerve, even when other shoulder muscles are compromised.¹⁸ This anatomical characteristic allowed surgeons to redirect the LTT to compensate for lost external rotator function, restoring stability, and range of motion (ROM) in affected patients. As the understanding of shoulder biomechanics evolved, the application of LTT transfer expanded beyond nerve injuries to include massive irreparable rotator cuff tears, particularly in patients with external rotation weakness and limited treatment options.²³ Unlike conventional rotator cuff repair techniques, which rely on viable tendon tissue for successful reconstruction, LTT transfer provides an alternative by offering a muscle-driven solution that rebalances the glenohumeral joint.

One of the primary reasons LTT transfer has become increasingly favored as a treatment option for PSIRCT is its biomechanical similarity to the infraspinatus, making it particularly well suited for restoring external rotation in cases of posterior–superior cuff deficiency.^15,32, 33, 34 The lower trapezius originates from the spinous processes of T6-T12 and inserts onto the spine of the scapula, providing a natural line of pull that closely mimics the infraspinatus.³³ This alignment allows for efficient force transmission and maintains normal shoulder kinematics, making LTT transfer biomechanically superior to other tendon transfer options, such as latissimus dorsi (LD) transfer, which contracts out of phase with the native external rotators and may result in suboptimal restoration of external rotation.^8,34 In addition, LTT transfer helps restore the posterior force couple of the shoulder by recentering the humeral head and preventing superior migration, which is commonly seen in massive rotator cuff tears.¹¹ Studies have demonstrated that LTT transfer leads to improved functional outcomes, ROM, and pain relief compared to alternative tendon transfers.^8,10

As surgical techniques continue to evolve, the refinement of arthroscopically assisted LTT transfer has contributed to its increasing adoption, allowing for less invasive procedures while preserving soft-tissue integrity. This technique has broadened the applicability of LTT transfer, making it a viable joint-preserving alternative to reverse total shoulder arthroplasty, especially in younger, active patients who seek to maintain their native shoulder function. This review aims to provide an in-depth analysis of the existing literature, discuss the evolution and refinements in surgical techniques, compare LTT transfer with alternative tendon transfers, and explore emerging advancements that may further improve its efficacy in clinical practice. As surgeons continue to seek optimal solutions for managing PSIRCTs, understanding the role of LTT in restoring shoulder function is essential for guiding clinical decision-making and improving patient outcomes.

Indications and contraindications

LTT transfer is indicated for shoulders with PSIRCTs without significant glenohumeral joint cartilage degeneration or anterosuperior escape.^7,21,23,43 While some surgeons advocate for LTT transfer in all cases in which reverse total shoulder arthroplasty (rTSA) is best avoided, others adopt a more selective approach based on patient-specific factors. Currently, there is no universal consensus on precise indications and contraindications, but the most widely accepted criteria include: (1) persistent pain and/or significant loss of shoulder function; (2) failure of conservative treatment, including physical therapy and injections; (3) symptomatic PSIRCTs with poor muscle quality of the supraspinatus and infraspinatus, classified as Goutallier²⁶ grades 3 and 4; (4) an intact or repairable subscapularis tendon, categorized as grade ≤ II in the Lafosse³⁰ classification; and (5) minimal or no arthritic changes, with a Hamada²⁷ grade ≤ 2. LTT transfer is contraindicated in cases where (1) advanced glenohumeral osteoarthritis is present, particularly Hamada²⁷ grade > 3, for which rTSA may be more appropriate; (2) significant neurological impairments affect shoulder function, limiting the effectiveness of tendon transfer; and (3) active infections or other systemic conditions compromise surgical outcomes.^7,21,23,43 In such cases, alternative treatment options should be considered based on the patient's overall condition and functional demands.

Although severe loss of active elevation or pseudoparalysis has traditionally been considered a relative contraindication for tendon transfer due to concerns regarding limited restoration of active motion, emerging evidence suggests that this limitation may be less applicable to LTT transfer. In the recent comparative study⁹ evaluating superior capsular reconstruction (SCR), LD transfer, and LTT transfer for PSIRCTs with pseudoparalysis, LTT transfer achieved the highest reversal rate of pseudoparalysis (90%), along with superior improvements in active ROM, muscle strength, and patient-reported outcomes. These findings suggest that limited preoperative active elevation should not be considered an absolute contraindication for LTT transfer when glenohumeral arthritis is absent and deltoid function is preserved. However, the current evidence is limited to a small number of retrospective studies, and long-term, high-level data remain lacking. Therefore, LTT transfer should be considered cautiously in patients with severely limited active elevation, with careful patient selection and thorough pre-operative evaluation of deltoid function, residual cuff integrity, and glenohumeral cartilage status.

Biomechanical considerations

The biomechanics of LTT transfer hinge on its capacity to restore external rotation and elevation, functions that are compromised in posterior–superior cuff deficiency.³³ Cadaveric studies have demonstrated that LTT transfer effectively re-establishes the force couple in the shoulder, potentially reducing superior humeral head migration and restoring normal kinematics.^11,33,34 Electromyographic analyses further support its ability to compensate for the lost function of the infraspinatus, given its synergistic action with the remaining intact cuff muscles.^17,41 In addition, studies have shown that the vector of pull in LTT closely mimics the infraspinatus, providing a more anatomic restoration compared to LD transfer.^33,34 Biomechanical assessments by Omid et al³³ demonstrated that LTT transfer effectively restores compressive forces and humeral head stability, with optimal results when tensioned at 12N or 24N, closely replicating the intact rotator cuff. In contrast, LD transfer applied insufficient force in some conditions, failing to fully restore normal shoulder mechanics, while excessive tensioning of LTT at 36N led to overcorrection of humeral head shifts. In addition, Reddy et al³⁴ used computed tomography–based computational modeling to compare the biomechanical characteristics of LTT transfer and LD transfer at different insertion sites. Their findings indicated that LTT transfer produces significantly higher external rotation moment arms than LD transfer, particularly when inserted at the infraspinatus site. The study also found that LTT has greater muscle elongation (strain) compared to LD, supporting its greater excursion and improved force transmission for external rotation restoration. LTT transfer has been noted for its biomechanical advantage in restoring external rotation. Unlike LD transfer, which contracts out of phase with the native external rotators of the shoulder, LTT transfer contracts synchronously with these muscles, making it an ideal alternative.^33,34 The excursion and alignment of LTT transfer with the infraspinatus allow for a more natural restoration of glenohumeral kinematics, improving functional outcomes and reducing superior humeral head migration.¹¹

Despite these biomechanical advantages, the native LTT has a relatively short tendon length, which limits its ability to directly reach the greater tuberosity without excessive tension. As a result, interpositional graft augmentation is generally required to bridge the gap between the transferred tendon and the humeral footprint. The use of an interpositional graft allows appropriate tensioning of the transfer, prevents overtensioning that may compromise scapular kinematics or lead to overcorrection, and facilitates an anatomic insertion that preserves the favorable line of pull of the lower trapezius. Achilles tendon allograft is most commonly used because of its length, thickness, and biomechanical strength, although hamstring tendon or fascia lata autografts have also been described.^{2,13,15,18,19,39,43} Proper graft length and tensioning are critical to optimize force transmission, restore external rotation, and avoid altered glenohumeral mechanics.

Surgical techniques and variations

Standard protocol for lower trapezius tendon

Arthroscopically assisted LTT transfer follows standard protocol initially described by Elhassan et al.¹⁹ This procedure is typically performed with the patient in the beach-chair position.^{15,19,21,24,35,42,43} However, the lateral decubitus position with arm traction, which provides greater working space and improved tissue handling, can also be used.² The choice of positioning depends on surgeon preference and patient-specific considerations.

The procedure begins with the harvesting of the LTT. A horizontal incision is made just inferior and parallel to the medial half of the spine of the scapula. The inferior edge of the LTT is carefully elevated using forceps to expose the dissection plane between the trapezius and the underlying infraspinatus fascia. The tendon is then detached subperiosteally from lateral to medial, ensuring preservation of the neurovascular pedicle to maintain function and avoid complications (Fig. 1A).

Figure 1.

Surgical procedure of lower trapezius tendon transfer. (A) Harvested lower trapezius tendon [whiteasterisk] with traction suture. (B) Arthroscopic view from posterolateral portal showing interpositional graft [redasterisk] fixed to humerus. (C) Interpositional graft [whitearrow] attached along the inferior border of lower trapezius.

Once harvested, an interpositional graft is prepared to bridge the gap between the transferred LTT and the greater tuberosity of the humerus. Achilles tendon allograft is the most commonly used graft, although hamstring tendon and fascia lata autografts are viable alternatives.^1,2,6,37,43 (Fig. 2) The distal (calcaneal) end of the graft is reinforced with #2 nonabsorbable sutures in a running locking configuration to enhance fixation strength.

Figure 2.

Types of interpositional graft. (A) Prepared Achilles tendon allograft [redasterisk]. (B) Prepared fascia lata autograft [whiteasterisk].

The arthroscopic portion of the procedure begins with subacromial space preparation, where an arthroscope is introduced through a posterolateral portal, and a lateral subacromial portal is used to clear the bursa. If a partial repair of the rotator cuff is feasible, a side-to-side repair is performed, integrating saved sutures into the interpositional graft fixation to optimize healing. The infraspinatus fascia is then divided, allowing the graft to be passed into the subacromial space and retrieved anteriorly.

The interpositional graft is then secured to the humerus by wrapping it horizontally around the humeral head and fixing it to the anterior aspect of the greater tuberosity using knotless anchors (Fig. 1B). Finally, the graft is securely attached to the prepared LTT using the Pulvertaft technique, ensuring strong tendon-to-tendon integration and maximizing force transmission for external rotation restoration.

Modifications and alternative techniques

While the standard protocol for LTT transfer remains the foundation of the procedure, several modifications have been introduced to enhance graft integration, fixation techniques, and procedural efficiency. Some modifications focus on surgical timing and intraoperative decision-making. While the standard approach involves harvesting the lower trapezius at the beginning of the procedure, in cases where rotator cuff repairability is uncertain, some surgeons prefer to delay the harvest until an intraoperative assessment determines whether LTT transfer is necessary. This approach provides greater flexibility in tailoring the surgical plan based on real-time findings. Alternative fixation techniques have also been explored to improve the stability of the graft-to-humerus interface. While knotless anchors are the standard method of securing the interpositional graft to the greater tuberosity, double-row suture bridge fixation technique can be used to increase bone-to-graft contact, enhances load distribution, and may improve healing rates by reducing micromotion at the tendon–bone interface.² Also, humeral bone tunnel–based tendon grafting technique can be for the fixation method.⁴⁰ In addition, graft augmentation using an acellular dermal matrix graft has been introduced to reinforce the interpositional graft, particularly in cases in which tissue quality is compromised.⁵ Acellular dermal matrix augmentation provides a biocompatible scaffold, enhances graft integration, and has been suggested to improve suture retention properties, further optimizing the biomechanical stability of the transfer.^25,38 Finally, alternative attachment methods exist for securing the interpositional graft to the LTT. Instead of the standard attachment method, such as the Pulvertaft technique,¹⁹ interpositional graft can be attached along the inferior border of the harvested LTT² (Fig. 1C). This method increases the contact area between the interpositional graft and the lower trapezius, reducing the risk of retear and avoiding the formation of a pseudomass, which may result from the bulkiness of the Pulvertaft weaving technique. By integrating these technical refinements and alternative approaches, LTT continues to evolve as a highly effective and adaptable procedure for restoring shoulder function and external rotation in patients with irreparable posterior–superior rotator cuff tears.

Clinical outcomes of lower trapezius tendon transfer

Several studies have evaluated the outcomes of LTT transfer for PSIRCTs. Elhassan et al²³ first reported on the outcomes of open LTT transfer in 33 shoulders, with patients ranging in age from 31 to 66 years (mean, 53 years). At a mean follow-up of 47 months, all but one patient experienced improvements in Visual Analogue Scale (VAS), Subjective Shoulder Value, and Quick Disabilities of the Arm, Shoulder, and Hand scores. The average post-operative ROM included 120° of forward flexion and 50° of external rotation, with poorer outcomes associated with limited pre-operative active elevation. Later, the same group reported on arthroscopically assisted LTT transfer in 41 patients with a mean age of 52 years, including 19 shoulders with true pseudoparalysis.²¹ At follow-up, all but 5 patients demonstrated clinical improvements, with 2 experiencing transfer failure and 2 requiring conversion to rTSA.

Many other authors have reported the clinical outcomes of arthroscopically assisted LTT transfer. Stone et al³⁹ analyzed 15 patients who underwent LTT transfer, performed either open or arthroscopically, with a mean age of 52 years. Among these, 93% were manual laborers, and 60% had workers' compensation claims. Three patients required conversion to rTSA, while the remaining 12 showed significant improvements in American Shoulder and Elbow Surgeons (ASES), Single Assessment Numeric Evaluation, and SST scores at two years. Notably, patients with poor pre-operative active elevation exhibited worse post-operative outcomes. Chopra et al¹⁴ evaluated 19 patients (mean age, 56.7 years), of whom 80% had previously failed rotator cuff repairs. At an average follow-up of 14.6 months, significant improvements were observed in VAS pain scores (6 to 2), ASES scores (45 to 71), Patient Reported Outcomes Measurement Information System (PROMIS) physical scores (43 to 52), and external rotation (10° to 40°). At the final follow-up, there was an improvement in strength from 2.8/5 ± 1 to 4.7/5 ± 0.5. Magnetic resonance imaging at six months demonstrated complete tendon healing in 90% of patients. Furthermore, 76.4% of eligible patients were able to return to work. Baek et al⁷ recently reported mid-term outcomes of arthroscopically assisted LTT transfer using an Achilles tendon allograft in 36 patients (mean age, 63.4 years) with a follow-up period of 58.2 ± 5.3 months. At the final follow-up, significant improvements were observed in VAS, Constant, ASES, University of California, Los Angeles, and Activities of Daily Living in External Rotation scores, along with increased active ROM in all directions except internal rotation. However, a decrease in the acromiohumeral distance and an increase in Hamada grade were noted (P = .040 and P = .006, respectively). Retears of the transferred tendon occurred in 7 patients, and 2 patients developed post-operative infections. A recent systemic review by Clouette et al¹⁵ analyzed 18 studies covering 3 aspects: biomechanics, technique, and clinical outcomes. The study suggests that LTT transfer is generally safe, with current clinical and biomechanical data supporting its use for restoring function in these challenging patient populations. A systematic review by De Marinis et al¹⁶ analyzed data from 159 patients across 7 studies, with a mean age range of 52-63 years and a follow-up period of 14-47 months. The review found that LTT transfer resulted in substantial improvements in forward elevation (mean gain of 10° to 66°) and external rotation (11° to 63°), with complete reversal of pre-operative external rotation lag signs. Patient-reported outcomes also showed consistent improvement. The overall complication rate was 17.6%, with seroma or hematoma being the most common (6.3%). The most frequent reoperation was conversion to rTSA (5%), contributing to an overall reoperation rate of 7.5%. These findings suggest that arthroscopically assisted LTT transfer can yield favorable outcomes, even in patients with pseudoparalysis, though pre-operative cuff arthropathy may negatively impact results.

Comparative studies of lower trapezius tendon and other surgical options

Comparative studies have assessed LTT transfer relative to other reconstructive options, such as LD transfer and SCR. Baek et al⁸ conducted a comparative study of LD transfer versus LTT transfer for PSIRCTs, analyzing 48 patients who underwent arthroscopic assisted LD transfer and 42 who underwent arthroscopically assisted LTT transfer. While both procedures led to significant improvements in clinical outcomes, LTT transfer demonstrated superior shoulder ROM, functional improvement, and reduced progression of arthritis. These findings suggest that LTT transfer may be the preferred option for relatively young and active patients requiring tendon transfer for PSIRCTs. Another study compared SCR and LTT transfer in patients with PSIRCTs and grade 4 fatty infiltration of the infraspinatus.¹⁰ While both procedures resulted in significant clinical improvement, LTT transfer demonstrated superior outcomes in forward elevation (165.7° vs. 145.5°), external rotation (51.7° vs. 41.1°), ASES scores (84.8 vs. 76.8), and patient satisfaction (8.9 vs. 6.4). In addition, the rate of arthritis progression was lower after LTT (2.8% vs. 22.7%), and SCR had a significantly higher graft retear rate (63.6% vs. 8.3%). Marigi et al¹⁶ also compared SCR and LTT transfer, noting that LTT transfer was preferred for patients with substantial external rotation lag and more advanced fatty infiltration of the teres minor. At a mean follow-up of three years, patient-reported outcome scores were similar between groups, with SCR patients experiencing slightly better pain relief and elevation, while LTT transfer provided greater external rotation improvement. The complication and reoperation rates did not differ significantly. Similarly, Wagner et al⁴⁴ compared SCR with tendon transfer (either LD transfer or LTT transfer) in 163 patients who underwent SCR and 24 who received tendon transfers. Both groups showed improved pain and function at two years, with no significant differences in clinical outcomes.

rTSA has been reported as a viable salvage option following failed tendon transfer for PSIRCTs, although available data remain limited. Marigi et al³¹ evaluated mid-term outcomes of rTSA after failed tendon transfer, including LD, combined latissimus dorsi–teres major (LDTM), and LTT transfers, and demonstrated significant improvements in pain, ROM, and patient-reported outcome measures that exceeded minimal clinically important difference thresholds. Notably, complication rates differed according to the type of prior tendon transfer, with LDTM transfer showing the highest complication rate (3 shoulders, 50%), followed by LTT transfer (1 shoulder, 16.7%), whereas isolated LD transfer had the lowest complication rate (3 shoulders, 14.3%; P = .037). Implant survivorship free of revision or reoperation was estimated at 90.1% at 1 year, 84.9% at 2 years, and 71.2% at 5 years, with no significant differences among tendon-transfer groups (P = .654). These findings suggest that although rTSA can reliably improve clinical outcomes after failed tendon transfer, the type of prior transfer may influence post-operative complication risk and should be considered when counseling patients and planning revision strategies.

Evolving indications and innovations in lower trapezius tendon

The role of LTT transfer continues to expand beyond its traditional indications, with increasing interest in its use as a primary treatment for PSIRCTs in younger patients and as a salvage procedure following failed rTSA. A novel approach, known as the "parachute technique" or dual reconstruction, combines LTT with LDTM transfer.^4,20 (Fig. 3) Traditionally, tendon transfers were reserved for patients who retained either functional internal or external rotation, as single tendon transfers typically addressed deficits in only one plane of shoulder motion. By integrating both anterior and posterior tendon transfers, this technique aims to restore external and internal rotation simultaneously, offering a more comprehensive solution for patients with global shoulder dysfunction. However, clinical validation remains limited, highlighting the need for further research. Another emerging approach involves combining the middle trapezius tendon transfer with LTT using a split Achilles tendon allograft in a Y-configuration.³ This method not only reconstructs the irreparable supraspinatus tendon but also provides a spacer effect in the subacromial space, enhancing dynamic glenohumeral joint stability. LTT transfer can also be performed in conjunction with other surgical procedures, including SCR³⁶ and long head of the biceps SCR.¹³ Early clinical outcomes suggest significant pain relief and functional improvement in patients with PSIRCTs without arthritis.

Figure 3.

Dual reconstruction. Final appearance of dual reconstruction consisted of anterior latissimus dorsi and teres major tendon [whiteasterisk] transfer and posterior lower trapezius tendon [redasterisk] transfer.

Recent studies indicate that LTT transfer may also be a viable option for older patients, achieving comparable functional outcomes to younger cohorts. Kim et al²⁸ reported no significant difference in clinical outcomes between patients aged ≤60 years and those aged ≥70 years undergoing LTT transfer for PSIRCTs with minimal glenohumeral arthritis. As more elderly individuals maintain active lifestyles, LTT transfer may serve as a joint-preserving alternative to rTSA, provided that cartilage integrity is preserved. LTT transfer has also demonstrated high rates of return to work and sports among active patients. Kim et al²⁹ found that 93.6% of patients returned to work, with a mean return time of 5.2 ± 1.7 months, while 90.7% returned to sports, with a mean return time of 5.7 ± 1.3 months. Patients with lighter occupational demands experienced higher return rates and quicker recovery times compared to those with physically demanding jobs. These findings suggest that LTT transfer is not only an effective reconstructive option but also a procedure that supports functional restoration and reintegration into daily activities for a wide range of patients.

Conclusion

LTT transfer has emerged as a viable surgical option for patients with PSIRCTs, offering promising biomechanical and clinical outcomes. Advances in surgical technique, biologic augmentation, and patient selection criteria will likely enhance its efficacy and expand its indications in the future. Continued research is essential to further refine this technique and optimize functional restoration for patients with complex shoulder pathologies.

Disclaimers:

Funding: No outside funding or grant was received for this study.

Conflicts of interest:The author, their immediate family, and any research foundation with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.