Subscapularis Management in Total Shoulder Arthroplasty: Current Evidence Comparing Peel,Osteotomy,and Tenotomy

Abstract

The optimal approach to management of the subscapularis in total shoulder arthroplasty (TSA) is controversial. Options include the subscapularis tenotomy, lesser tuberosity osteotomy (LTO), and peel. This review provides a summary of subscapularis anatomy and function, outcomes associated with subscapularis management options in TSA, and postoperative subscapularis deficiency. Based on the available literature, LTO appears to result in improved function and subscapularis integrity relative to tenotomy, while peel and LTO have generally led to equivalent outcomes. The highest level of evidence to date is derived from a randomized controlled trial that demonstrated that outcomes following peel and LTO were not significantly different. There is currently a paucity of high-quality evidence as most studies have consisted of small retrospective series with varying outcome measures. Furthermore, the optimal approach to establishing the diagnosis of subscapularis deficiency following TSA is unclear.

Keywords

Subscapularis shoulder arthroplasty tenotomy osteotomy peel

Introduction

Total shoulder arthroplasty (TSA) is a reliable option for treating pain and improving function in patients with glenohumeral arthritis after conservative measures have failed.^1–4 Access to the glenohumeral joint is most commonly achieved through the deltopectoral approach with mobilization of the subscapularis (SSC).^2,5 Tenotomy of the SSC medial to its insertion on the humerus has traditionally been performed.⁶ However, some studies have reported high failure rates and poor clinical outcomes following this technique.^7,8 Lesser tuberosity osteotomy (LTO) and SSC peel were subsequently developed with the goal of improving postoperative healing, integrity, and function.^5,9,10 Currently, controversy exists as to which technique yields optimal results in TSA.

Anatomy and Function of the SSC

Muscular Anatomy

The SSC is a triangular muscle with a broad-based muscle belly that originates on the anterior surface of the scapula.¹¹ The superior two-thirds of the muscle contains 4-to-6 thick tendon slips composed of thick collagen fibers that arise within the muscle and form a tendon that courses laterally to insert on the lesser tuberosity of the humerus.^11–13 The inferior one-third of SSC is muscular in nature throughout its course from origin to insertion on the humeral neck distal to the lesser tuberosity.¹⁴ The footprint of the SSC on the humerus is comma shaped.¹⁴ In the transverse plane, the SSC footprint is widest superiorly with an average width of 9.4 mm and tapers inferiorly to an average width of 7.1 mm.¹⁵ The average longitudinal length of the SSC footprint is 29.2 mm.¹⁵ The anterior capsuloligamentous complex is associated with the SSC as it attaches onto the humerus, which leads to the creation of a combined ellipsoid footprint with the SSC.¹⁵

Innervation and Function

Innervation to the SSC is supplied by the upper and lower subscapular nerves that typically branch off the posterior cord of the brachial plexus, although anatomic variants exist in which the lower subscapular nerve arises from the axillary nerve or thoracodorsal nerve.¹⁶ The lower subscapular nerve enters the SSC at an average distance of 35 mm medial to the center of the glenohumeral joint, although it may course as close as 19, 15, and 9 mm with shoulder in internal, neutral, and external rotations, respectively.^16,17 Given this proximity, care should be taken to avoid aggressive medial dissection during exposure and SSC release. Staying lateral to the coracoid base also helps to avoid nerve injury.

The axillary nerve is located 33 mm inferior to the inferior border of the SSC.¹⁸ Injury to this nerve can be avoided by ensuring the nerve is identified and palpated, avoiding extreme arm positions for prolonged periods, and frequently readjusting retractors, especially during glenoid exposure. Finally, neuromonitoring can also be used during shoulder arthroplasty as an added measure of safety.¹⁹

SSC function is primarily internal rotation of the shoulder but can affect other motions depending on the position of the humeral head.²⁰ The SSC forms the anterior portion of the rotator cuff and forms a force couple with the posterior rotator cuff that compresses the humeral head into the glenoid.^20,21 The SSC aids in translation of the humeral head inferiorly during contraction of the deltoid to allow for abduction and elevation of the humerus.²² Lastly, the SSC provides a block to anterior dislocation of the humerus on the glenoid.²³

Options for SSC Management in TSA

Tenotomy

A standard deltopectoral approach is used for SSC tenotomy, LTO, and peel techniques.^6,24 The plane between the SSC and the conjoined tendon is developed with blunt dissection. A blunt self-retaining retractor can then be placed between the anterior edge of the deltoid and the lateral edge of the conjoined tendon. The biceps tendon is identified within the bicipital groove and tenotomized or tenodesed to the proximal humerus or pectoralis major tendon. The rotator interval is opened, which allows identification of the upper border of the SSC. The inferior aspect of the SSC tendon is demarcated by the location of the anterior humeral circumflex artery and its 2 venae commitantes. It is helpful to ligate these vessels prior to tenotomy to maintain hemostasis. Stay sutures are placed in the SSC tendon, and the tenotomy is carried out 1 to 2.5 cm medial to the bicipital groove. The tendon and capsule are opened in a single layer from superior to inferior proceeding along the humeral neck. The exposure continues as the shoulder is gradually externally rotated, and a complete anteroinferior capsular release off the humeral neck is performed. Release allows 90° of external rotation and dislocation of the humeral head. Deep to the SSC, a release is carried out along the anterior capsule to 5 o’clock (right shoulder). The axillary nerve is particularly at risk during this release and as such must be carefully protected and identified at this time. Additional glenoid releases may be necessary in order to achieve glenoid exposure. Sanchez-Sotelo recently provided a review of the surgical technique of SSC tenotomy in TSA.

Following TSA, the SSC is repaired with at least 3 heavy nonabsorbable braided high-tensile strength sutures.^7,25–28 Repair is carried out using tendon-to-tendon repair with a Mason-Allen suture technique, tendon-to-bone repair through transosseous tunnels in the bicipital groove—which is comprised of relatively dense bone—or a combination of these techniques.^6,27,29,30 Biomechanical testing has not demonstrated a clear superiority of 1 repair technique.^26,27,31,32

SSC tenotomy has been the most commonly used approach to access the glenohumeral joint.^3,4 Secure repair is necessary to promote healing and prevent early failure. Although failure of SSC tenotomy is likely an underrecognized complication, some authors have reported consistently favorable results with tenotomy.³³ Caplan et al. observed no ruptures and good function following SSC tenotomy repair based on clinical examination.³⁴ However, clinical examination alone is likely not adequate to confirm failure, and other studies have reported higher rates of failure.^7,8 Miller et al. found that the majority of patients treated with tenotomy and repaired with tendon-to-tendon repair or combined soft tissue and transosseous repair had reduced SSC function on physical examination.⁸

SSC tenotomy has various benefits that include simplicity of technique, use in stemless arthroplasty, shorter operative time, and the potential for lengthening in cases of severe external rotation contracture. The main disadvantage is a higher structural failure rate compared with other techniques.^7,8,35,36 Although new techniques are gaining popularity, SSC tenotomy continues to be an option for SSC management given that reliability and reasonable clinical results have been demonstrated by those who consistently use this technique.

Lesser Tuberosity Osteotomy

LTO involves elevating the SSC with a fragment of bone off the lesser tuberosity (Figure 1).^5,9 An osteotome or microsagittal saw is used to create a division in the bone (lesser tuberosity)–cartilage (humeral head) transition zone. LTO is carried out along the medial edge of the bicipital groove (Figure 1). The arm is held in adduction and internal rotation, and a bone fragment is elevated. Traction sutures are placed around the osteotomized fragment, and tendon mobilization is performed as per the tenotomy technique. The osteotomy is repaired using heavy nonabsorbable braided high-tensile strength sutures that are passed around the fragment and looped around the humeral stem or through transosseous tunnels and tied over a minifragment plate on the greater tuberosity (Figure 1).³⁷ LTO can also be repaired using wires for rigid fixation, which is not possible with the tenotomy or peel.³⁸

Figure 1.

Lesser Tuberosity Osteotomy (LTO). A, The subscapularis (a) is elevated with a fragment of lesser tuberosity (b) that is osteotomized from the humerus with a microsagittal saw (c) along the medial edge of the bicipital groove (d, dotted line). Traction sutures are present around the osteotomized fragment (e). B, Transosseous suture repair of LTO through transosseous tunnels (a) created from the bicipital groove (dotted lines) to the greater tuberosity. Heavy nonabsorbable braided high-tensile strength sutures (b) are passed around the osteotomized fragment (c). Sutures are then passed through the transosseous tunnels in horizontal mattress formation and tied over a minifragment plate (d).

Several variations of LTO and osteotomy repair have been described in the literature with no consensus on the optimal technique.³⁶ The traditional osteotomy (3–4 cm in vertical length, 5–10 mm in lateral width, and 5–8 mm in thickness),^5,9 thin wafer osteotomy (2.5 cm² in circular area and 4–5 mm in thickness),^31,39 and fleck osteotomy (2 cm in length, 1 cm in width, and 3–4 mm in thickness)³⁵ have been described. Repair techniques include the single-row repair,³⁵ dual-row or “cornrow” repair,^35,40 tension-band or “backpack” technique,^9,26,40 compression configuration involving suture around the stem,³⁹ and cerclage cable augmentation.⁴¹

LTO was introduced as a procedure to reduce the prevalence of SSC dysfunction after TSA.^5,8,9,31,42 Miller et al. reported SSC deficiency in two-thirds of their patients managed with SSC tenotomy and advocated for LTO with the goal that bone-to-bone contact would improve healing rates.⁸ Other studies noted up to 100% healing rate after LTO and repair.^5,43 Benefits of LTO include bony healing and protection of the tendon–bone interface. While the evidence may largely be circumstantial, bone-to-bone healing is generally regarded as superior to tendon-to-bone healing or tendon-to-tendon healing.^27,35 This represents a theoretical advantage of the LTO. Failure of the LTO can be detected radiographically, which is not seen with other techniques. In general, the LTO may facilitate glenoid exposure, and if a traditional diaphyseal fixated humeral component is used, a larger osteotomy can be used to potentially facilitate further exposure. Downsides include intraoperative fracture during osteotomy and postoperative nonunion.^6,37 Furthermore, recent design changes with shorter press-fit humeral stems and stemless components require tight metaphyseal fit and a solid ring of bone at the humeral neck, respectively, for implant stability. Therefore, the LTO potentially risks fixation failure of a proximally fitting humeral component.

Peel

SSC peel starts by identifying the bicipital groove and biceps tendon (Figure 2). The biceps tendon is followed superiorly into the joint, and the rotator interval is opened. The biceps tendon is tenotomized or tenodesed as per surgeon preference. The borders of the SSC are identified superiorly by palpation of the relatively thickened superior margin, and the anterior circumflex humeral vessels inferiorly. These vessels are then ligated. Heavy braided stitches are placed in mattress fashion in the SSC tendon for retraction and control. The peel starts at the lateral edge of the lesser tuberosity just medial to the bicipital groove by subperiosteally elevating the tendon and anterior capsule in 1 layer from the bone.⁴⁴ The humerus is progressively externally rotated until sufficient release of the tendon and anterior capsule allow 90° of external rotation. The releases of the SSC start superiorly by dividing the coracoid humeral ligament, which tethers the upper border to the base of the coracoid. The anterior capsule can be freed from its attachments to the deep surface of the tendon and is released all the way around to the inferior aspect of the glenoid ensuring the axillary nerve is identified and protected at all times. Increased mobility of the tendon should be noted once the releases have been accomplished.

Figure 2.

Subscapularis (SSC) Peel. A, The biceps tendon (a) and SSC (b) are identified. B, Medial to the bicipital groove (a), the proposed border of the SSC peel (b) is marked (dotted line). C, The peel is performed from the lateral edge of the lesser tuberosity (a) by subperiosteally elevating the tendon and anterior capsule in 1 layer from the bone. D, Transosseous suture repair of SSC peel through transosseous tunnels (a) created from the bicipital groove to the greater tuberosity. Heavy nonabsorbable braided high-tensile strength sutures (b) are passed through the SSC (c) and transosseous tunnels and then tied over a minifragment plate (d).

Repair of the tendon is typically done in the same fashion as described for the LTO using transosseous sutures. The authors’ preferred method is to pass heavy inverted horizontal mattress sutures through the bicipital groove out the greater tuberosity and tie these sutures over a minifragment plate to prevent suture or bone cutout (Figure 2).³⁷

SSC peel may be more appropriate than other techniques when the SSC insertion has to be medialized to allow for increased external rotation.²⁴ Peel increases the area available for tendon healing (to bone) relative to the SSC tenotomy. A direct comparison of healing rates between SSC tenotomy and peel has not been reported to date. Outcomes following SSC peel have been positive.^37,45 SSC deficiency following repair has been reported in a small percentage of cases and shown to be associated with lower functional outcomes.⁴⁵

Biomechanical Comparison of Techniques

The biomechanical properties of SSC management techniques have been assessed in cadaveric studies. Giuseffi et al. observed no significant difference in load to failure between tenotomy and LTO but found less displacement during cyclic testing with tenotomy.²⁵ Van den Berghe et al. demonstrated that LTO with bone-to-bone repair and tenotomy with tendon-to-tendon repair had lower failure rates than peel with tendon-to-bone repair.²⁶ However, Van Thiel et al. reported no significant differences in biomechanical outcomes after repair of tenotomy, LTO, and peel.²⁷ In a systematic review, Schrock et al. concluded that the majority of studies demonstrated superiority of LTO over soft tissue methods in terms of load to failure, although there was no difference in cyclic displacement.³⁶

Clinical Comparison of Techniques

Clinical studies have not consistently demonstrated superiority of one SSC management technique over other techniques.^7,37,45 Variability in outcome based on functional scoring has been demonstrated between SSC tenotomy, LTO, and peel. At least some of the differences noted in function appear to relate to SSC integrity and deficiency.^45–47

A retrospective review by Jandhyala et al. comparing SSC tenotomy and LTO demonstrated that the LTO group had higher strength scores.⁷ Several other studies have compared SSC peel and LTO with respect to functional outcomes.^{10,37,43,45,48} Scalise et al. retrospectively compared LTO to peel, which was termed “tenotomy” but had a surgical technique in keeping with a peel procedure rather than a traditional tenotomy.⁴³ They demonstrated that clinical outcome scores improved in both groups from the preoperative to postoperative period. The LTO group had significantly higher function based on Penn Shoulder Scores. No differences were observed in internal rotation strength. In a prospective double-blind randomized controlled trial by Lapner et al. comparing peel and LTO, no significant functional differences were observed at 2 years between groups on SSC strength, Western Ontario Osteoarthritis of the Shoulder (WOOS) index, and American Shoulder and Elbow Surgeons (ASES) score.^10,37,48 In a retrospective cohort study, Buckley et al. reported no significant differences between LTO and peel on Disabilities of Arm, Shoulder and Hand (DASH) and Constant scores. After controlling for follow-up imbalance, the difference in WOOS scores approached statistical significance but lacked clinical significance.⁴⁵

Based on functional outcomes, all 3 approaches to SSC management have yielded reasonable results. LTO appears to have resulted in improved functional scores relative to tenotomy.⁷ Peel and LTO have led to equivalent outcomes in multiple studies, while LTO was superior in another study.^10,43,45 Factors that should be taken into account in choosing an approach include surgeon preference, requirement for SSC tendon medialization, degree of SSC tendon robustness, implant design, and the ability to follow SSC healing postoperatively. It should be noted that surgeons may choose a different technique based on individual variations in proximal humeral anatomy or in cases in which a difficult exposure may make LTO a preferred option.

SSC Deficiency After TSA

Evaluation of SSC Deficiency

Patients with SSC deficiency following TSA may present with anterior instability, pain, reduced mobility, weakness, and decreased function.^33,49–51 Physical examination maneuvers that demonstrate SSC deficiency include belly-press test, lift-off test, and bear-hug test.^37,45,52 Although these maneuvers may aid in the diagnosis, several studies have demonstrated that they lack reliability and consistency.^29,47,53 With anterior dislocation in the setting of SSC failure, an anterior prominence may be noted on inspection along with decreased range of motion.⁵⁴ Radiography allows for identification of subluxation or dislocation of the prosthetic humerus. However, this may be limited by difficulty in obtaining high-quality axillary views.⁵⁵ If LTO has been performed, displacement of the bone fragment may be visualized. Ultrasound is used to assess SSC integrity and may demonstrate whether the tendon is attenuated or ruptured.^43,45 Magnetic resonance imaging and computed tomography (CT) are capable of determining the humeral head position and SSC quality and integrity, although tendon assessment may be limited by metal artifact.^37,56 Furthermore, these imaging modalities may allow identification of additional causes of anterior instability that include component anteversion, component loosening, glenoid bone loss, and massive rotator cuff tear.^42,54,55

Incidence of SSC Deficiency

SSC deficiency has been reported as an infrequent complication in 1% to 6% of patients within large studies that assessed hundreds of patients after TSA.^{33,42,46,54,55,57} Across studies, SSC deficiency was defined variably as tear, rupture, detachment, or deficiency. When reported, only a fraction of patients underwent reoperation for treatment of SSC deficiency. In a multicenter series of 555 shoulders in 514 patients with a minimum follow-up of 2 years, Edwards et al. reported early SSC detachment within 3 weeks of surgery in 0.4% of cases, SSC tear in 0.7% of cases after 3 weeks, and suspected SSC tear in an additional 1.1% of cases (deficiency in 1%–2% total).⁴⁶ Boileau et al. published an update on this series that involved 1542 cases and reported an incidence of SSC rupture or deficiency in 2% of patients at a minimum follow-up of 2 years.⁵⁷ Young et al. found symptomatic SSC rupture in 2% of 596 patients at 8.6 years following TSA.⁵⁵ Only 0.3% of all patients underwent reoperation for treatment of rupture. In the assessment of 429 patients, Kany et al. reported that 1.6% of patients developed anterior instability related to SSC rupture that was subsequently treated surgically.⁴² In a single-center study by Moeckel et al., 3% of 236 shoulders developed anterior instability related to SSC rupture that required reoperation at an average of 9 months from the time of TSA.⁵⁴ Miller et al. reported that 5.8% of 119 patients had a second operation for treatment of symptomatic SSC at 1 year.³³

Importantly, a larger portion of patients undergoing TSA do not recover full range of motion or strength after surgery. Others may have ongoing unexplained pain. Because SSC failure may be silent after TSA without clear evidence on physical exam and radiographs, it is conceivable that the true incidence of failure is higher than reported. Furthermore, unless dedicated imaging is performed to assess SSC integrity, this complication may have been underreported in the literature.

Several smaller studies have published relatively higher rates of SSC deficiency following TSA within subgroups of patients treated with tenotomy, peel, or LTO.^7,8,43,47 Complete SSC compromise and partial SSC compromise have been elucidated through the use of various physical examination and imaging modalities. With respect to SSC dysfunction noted on physical examination, Miller et al. assessed 41 patients at a mean follow-up of 2 years and reported SSC weakness on exam in up to 83% of patients following SSC tenotomy with side-to-side repair and up to 67% following SSC tenotomy with transosseous repair.⁸ Jandhyala et al. reported abnormal SSC function on the graded belly-press test at a mean follow-up of 3 years in 7 of 10 patients treated with SSC tenotomy and 7 of 26 patients treated with LTO, while abnormal function on lift-off test was less frequent in 1 of 10 and 1 of 26 patients, respectively.⁷

Using imaging to assess SSC deficiency, complete SSC rupture was found on ultrasound in 7 of 15 patients following SSC tenotomy at a minimum follow-up of 6 months by Jackson et al.⁴⁷ Patients with tears had significantly impaired strength on the bear-hug test using dynamometry and internal rotation testing, while lift-off and belly-press testing correlated poorly with ultrasound. Based on ultrasound, Buckley et al. reported attenuated SSC tendons in 3 of 32 and a ruptured tendon in 1 of 32 patients treated with SSC peel assessed 32 months postoperatively.⁴⁵ Of 28 patients treated with an LTO, 1 patient had a nonunion noted over 22 months. Scalise et al. demonstrated that 6 of 15 SSC tendons were attenuated and 1 of 15 tendons was fully disrupted following peel, while 2 of 20 tendons were attenuated following LTO at a minimum of 1 year from TSA.⁴³ Based on CT imaging at 1 year, Lapner et al. reported healing rates of 41 of 41 and 39 of 41 for peel and LTO, respectively.³⁷ Fatty infiltration increased one-half of a Goutallier grade on average in each group following TSA. There was a trend toward lower SSC strength in those patients with increased fatty infiltration. The results of these studies suggest that SSC compromise that includes partial disruption or attenuation occurs at a higher rate than complete rupture following TSA. Furthermore, postoperative CT imaging has demonstrated that alteration in SSC anatomy with fatty infiltration is a common finding even when tendon healing has occurred.³⁷

Factors Associated With SSC Deficiency

SSC deficiency after TSA is associated with preoperative, intraoperative, or postoperative factors. Preoperative presence of poor tissue quality has been described as a cause of failure.^33,46,50,58 Intraoperative factors that promote secondary SSC deficiency include inadequate repair technique, poor tissue quality, compromise of the tendon during repair, and oversized implanted components.^33,56,58 The technique used for SSC management during TSA also appears to affect postoperative SSC integrity and isolated function.^7,37,43,59 Postoperative factors that promote failure of the repaired SSC following TSA include premature or aggressive rehabilitation, lack of patient compliance, and trauma.^33,60 Subsequent surgeries causing multiple insults on the soft tissue envelope also appear to promote SSC deficiency.³³ In this regard, SSC peel or LTO may be better able to withstand multiple procedures compared to a tenotomy in which the tissue can degrade and become weak and friable leading to failure.

Impact of SSC Management on Postoperative Deficiency

The comparative clinical studies assessing SSC management technique have investigated deficiency based on physical examination maneuvers that attempt to isolate SSC function and imaging that assesses SSC integrity.^{7,37,43,45,59} These studies have generally demonstrated that LTO and SSC peel produce similar postoperative SSC function and integrity, while SSC tenotomy leads to inferior outcomes. SSC tenotomy and LTO were retrospectively compared by Jandhyala et al. at a mean follow-up of 3 years.⁷ Patients treated with LTO scored significantly better on the graded belly-press test, while performance on the lift-off test was similar. It was discussed that the senior author changed his practice to use LTO after observing adverse outcomes related to SSC deficiency following tenotomy.

Several studies have investigated differences in SSC function and integrity between LTO and SSC peel. Scalise et al. compared LTO to peel at a mean follow-up of 3 years.⁴³ Despite differences noted on functional scoring, there was not a significant difference between groups on belly-press testing or internal rotation strength. A significantly higher number of abnormal tendons was found following SSC tenotomy (7 of 15 shoulders) than LTO (2 of 20 shoulders) on ultrasound. All LTOs demonstrated anatomic union on radiography. In a prospective trial, Lapner et al. reported no significant difference between LTO and peel in SSC strength in the belly-press position at a mean follow-up of 2 years.³⁷ Based on CT assessment at 1 year, there was no difference between groups in healing rates following repair (100% for the peel vs 95% for the LTO) or fatty infiltration. Similarly, Buckley et al. found no significant difference in belly-press or bear-hug testing between LTO and peel.⁴⁵ Ultrasonography demonstrated attenuated or ruptured SSC tendons in 4 of 32 patients treated with the peel, while all 28 tendons were normal following LTO with lack of radiographic union in 1 of 28. This study had a significantly longer follow-up duration in the peel group that may have influenced outcomes.

In contrast to the findings of the prior 3 studies that demonstrated comparable postoperative SSC function and integrity between LTO and peel, Shafritz et al. reported a significant difference in lift-off testing in a retrospective study. At a mean follow-up of 4 years, a significantly higher proportion of patients treated with LTO had a normal lift-off test than those treated with peel.⁵⁹ The differences noted between studies could relate to lack of consistency in follow-up and variability in the sensitivity and specificity of specific physical examination and imaging measures.^29,53 The available literature lacks a comparison of the impact of SSC management on SSC failure with complete rupture and requirement for repeat surgery. This comparison would require a large population given the low occurrence of complete rupture.⁵⁷

SSC Deficiency and Functional Outcome

Postoperative SSC deficiency appears to affect clinical outcomes. In a retrospective study of patients treated with TSA using SSC tenotomy, Jackson et al. reported significantly worse DASH scores in patients diagnosed with SSC ruptures on ultrasound.⁴⁷ Buckley et al. found significantly reduced WOOS and DASH scores in patients with attenuated or ruptured SSC tendons on ultrasound.⁴⁵ In contrast to these findings, fatty infiltration on CT was not associated with SSC strength, WOOS scores, or ASES scores based on the study by Lapner et al.³⁷ Furthermore, given that concentric loading of the glenoid component is essential for longevity of the implant, SSC deficiency conceivably results in eccentric loading and early glenoid loosening that would compromise implant survival.

Treatment of SSC Deficiency

SSC deficiency related to complete or partial disruption may warrant surgery if a patient has significant pain, weakness, or instability. Primary repair of the ruptured SSC is performed if the tissue is amenable to repair.^54,56 Unfortunately, frequently there is insufficient tissue for repair. In the setting of failure due to nonunion of LTO, bone graft or osteoinductive material may be used in an attempt to augment healing or the nonunited fragment may be excised followed by a tendon-to-bone repair.⁶⁰ Other significant causes of anterior instability such as component malposition, component loosening, and inappropriate component size relative to soft tissue balancing are also addressed at the time of surgery.^50,54

A pectoralis major transfer or reconstruction with Achilles allograft or hamstring autograft may be used for augmentation of repairs in which the available tissue is inadequate for complete repair.^33,51,54 Pectoralis major transfer has been shown to be insufficient in the setting of static anterior subluxation.⁶¹ Furthermore, outcomes are worse following pectoralis major transfer in the setting of chronically fatty infiltrated SSC.⁶¹ Latissimus dorsi transfer has also been proposed in the setting of SSC deficiency.⁶² The final and most reliable option in the treatment algorithm for SSC failure and anterior instability that have not successfully been managed by other treatment modalities is reverse TSA.^63,64 Modified Latarjet procedure and iliac autografting of the anterior glenoid have also been reported as alternative salvage procedures.^61,65 These may be considered before reverse TSA in younger patients.⁵⁶

Conclusions

SSC repair, healing, and integrity are essential following TSA. The optimal method for SSC management during TSA is currently controversial. SSC tenotomy, LTO, and peel have all yielded similar clinical results. LTO appears to result in improved functional outcomes relative to tenotomy, while peel and LTO have generally led to equivalent outcomes. The highest level of evidence is derived from a randomized controlled trial that demonstrated that outcomes following peel and LTO were not significantly different.¹⁰

There is a paucity of high-quality evidence given that most studies to date have been small retrospective series with varying outcome measures. Physical examination maneuvers such as the lift-off test, belly-press test, bear-hug test, and internal rotation strength have been commonly used. For imaging, ultrasound and CT have been employed. It is currently unclear whether these techniques reliably assess for SSC deficiency. Future investigation is required to elucidate outcome measures that consistently evaluate SSC integrity. Large randomized studies comparing SSC management techniques are required to determine the option that optimizes functional outcome and reduces the rate of secondary SSC deficiency.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

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