Arthroscopic Treatment for Massive Cuff Tears

Abstract

In the current literature, several definitions are provided for massive cuff tears. At the same time, a massive cuff tear can be reparable or irreparable. As a consequence, certain criteria need to be defined to address this issue of reparability—quality of tendon, status of muscle atrophy, bone of greater tuberosity, status of glenohumeral joint, and last but not least the clinical criterion, that is the functionality of shoulder. Several arthroscopic treatment options are described — from simple biceps tenotomy, partial reconstruction techniques with or without biologic augmentation, and superior capsule reconstruction to other rather new tools such as balloon spacer implantation.

1. Introduction

What is a massive rotator cuff tear? The definition is somehow inconsistent. Cofield [1] defined a massive cuff tear as a tear with a width larger than 5 cm; Gerber [2] defined an MCT intraoperatively as a tear that after extensive debridement appears to affect two or more tendons; other authors [3] take into consideration an exposure of the humeral head wider than 3 cm, which usually has a surface of more than 9 cm. On the other hand, Hamada and Fukuda looked at X-rays in patients with MCT and described the elevation of the humeral head in the absence of glenohumeral arthritis, and they proposed their well-known classification. However, if we analyze these definitions for MCT, they take into consideration the size but make no indication regarding reparability; therefore, an MCT is not necessarily an irreparable tear. Hamada and Fukuda radiologic classification indicates that when the tear is chronic and its chronicity leads to humeral head elevation, then it is generally accepted that the tear should be considered irreparable. Surgeons should understand this important distinction, as an MCT can be reparable when it is acute or most likely irreparable in a chronic situation.

So, the next thing that needs to done is to define what is irreparable; irreparable can be considered as being both unfixable and unhealable. Unfixable is the inability to physically repair the tendon back to bone after expensive releases. Irreparable may be also unhealable, as described by Gerber [2], as any repair that is achieved but that will most likely be followed by failure, such as the need for reoperation due to retear, poor postoperative motion or strength, or poor outcome [4]. The Gold standard of irreparability is intraoperative inability to repair after extensive releases.

Nevertheless, most of the times, it is difficult preoperatively to decide if an RC tear is irreparable; surgeons must also take into consideration intraoperative findings. In general, arguments of irreparability include advanced fatty infiltration according to Goutallier classification (Goutallier grade 3 or more), decreased acromiohumeral distance (less than 6 mm), dramatic decrease of tendon length, and poor-quality tendon tissue.

Pascal Boileau [5] looked at the problem from a different perspective and gave us 7 good reasons not to repair an RCT: no tendon, due to resorbtion; no rotator cuff muscle, due to atrophy, fatty infiltration; no good bone – greater tuberosity osteoporosis seen especially in women; no good joint – glenohumeral osteoarthritis; static superior and anterior humeral head subluxation; dynamic humeral head subluxation, due to pseudoparalysis; and previous surgery – destroyed anterior deltoid, low grade infection.

Patients with a massive cuff tear usually complain about shoulder pain and decrease of function, which is often declared as decrease of active anterior elevation and/or active external rotation; the symptoms may be singular or in combination. Generally, three questions need to be asked: is this shoulder functional or not? is the muscle balance preserved; second—is the long head of biceps present, as a painful shoulder can be caused by a long head of biceps subluxation; and third — in which plane is the shoulder unbalanced—vertical plane, horizontal plane, or both. Answering these questions may help us choose the right treatment tailored to the patients’ symptoms and the type of shoulder muscle imbalance. The management of irreparable rotator cuff tears can be achieved by both surgical and nonsurgical methods that can address both functional and non-functional shoulders. Certainly, we must consider non-operative treatment for the right patient—usually nonsurgical treatment consists of: medication such as anti-inflammatory drugs, injection of corticosteroids substances inside subacromial space, and physical therapy.

While non-functional shoulder may benefit from tendon transfers and/or reverse shoulder arthroplasty, for functional shoulders, there are several surgical options for repairing massive rotator cuff tears. Despite the rapidly increasing numbers of reverse shoulder arthroplasties, alternative options are available [6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18]; among those, we mention biceps tenotomy or tenodesis, arthroscopic debridement, partial repair, complete repair, augmentation of repair with different types of patches, superior capsular reconstruction, and muscle tendon transfer [19]. Recently, superior capsular deficiency can be treated by the use of various autografts/allograft; respected shoulder surgeons present several surgical techniques such as: rerouting the long head of biceps tendon, use of long head of biceps tendon as an autograft, use of semitendinosus as an allograft, or simpler methods — subacromial spacers [20]. In the literature [19, 21], there is a lack of consensus and lack of guidelines on the appropriate indications for specific surgical treatment options, although, recent work from [20, 22] present an agreement on treatment of massive irreparable rotator cuff tears by the Neer Circle of the American Shoulder and Elbow Surgeons [20, 22].

To improve the success rates of operative results, there are several factors to be considered according to [19, 23] who proposed that some specific aspects should be met in order to achieve the best clinical results: subacromial decompression should be performed thoroughly; integrity of the deltoid muscle fibers origin should be preserved; torn tendons should be adequately mobilized, and interval slide should be done whenever necessary; tendons should be repaired down to bone; postoperative rehabilitation is a must. In addition, Yoon [24] proposed two essential requirements: the repaired rotator cuff should be able to sustain early tension during the initial healing stage, and one must obtain a certain biological environment that favors the healing ability of the repair site—that is, the bone-tendon junction [19]. Thus, surgical treatment performed must ensure decompression and debridement of the subacromial space and considerable strength in the repaired area; in this way, the repaired rotator cuff will be able to stabilize the glenohumeral joint; at the same time, we emphasize once more that providing a good biological environment will sustain a maximum healing capacity, allowing for safe mobilization [19, 23].

2. Debridement and biceps Tenotomy

Arthroscopic debridement was traditionally applied to massive rotator cuff tears in old patients with comorbidities and low functional expectations [19, 21, 25]. Early results presented clinical benefits such as decreased symptoms and improved range of motion. Berth et al. [19, 26] published several studies proving that debridement alone is associated with temporary benefits; debridement alone did not improve shoulder strength [19, 27]. Consequently, as new arthroscopic repair techniques emerged, debridement has become less popular.

Biceps tendon lesions are an important source of shoulder pain and often accompany massive rotator cuff tears. Greenspoon et al. [19, 21] confirmed that shoulder pain and dysfunction are reduced after biceps tenotomy or tenodesis, inducing good satisfaction in patients [19]; however, the natural history of rotator cuff tears is not influenced by biceps procedures alone [19]. In addition, some studies [19] showed no significant clinical improvements after arthroscopic debridement and biceps tenotomy when compared to arthroscopic debridement alone [19, 21].

Another systematic review study [4] demonstrates that arthroscopic debridement procedures are followed by good midterm to long-term patient outcomes; all 16 included studies presented significant clinical improvement in pain and range of motion. Thus, arthroscopic debridement is presented as a safe and reproducible surgical option with a low risk of complication (4.1%) [4]. The included studies presented in [4] seem to underline that pain relief has a greater importance than improvements of shoulder function in patients older than 65 years that underwent debridement.

Walch et al. [28] reported that patients with MCT treated nonoperatively declared pain relief after spontaneous long head of the biceps ruptures [19, 28]. They compared these findings to the results after arthroscopic biceps tenotomy in the same category of patients; similar improvements in pain and range of motion were observed. But these studies involving biceps showed decreases in the acromiohumeral distance, which seems logical if one takes into consideration the depressor effect of the long head of the biceps onto the humeral head [19, 29, 30]. Interestingly, patients still declared reduced pain and slightly better outcomes despite associated superior humeral head elevation [19, 29, 30]. Walch [28] also mentioned that fatty infiltration had negative prognostic effect on function and X-ray progression of arthritis.

Boileau [31] presented 72 irreparable cuff tears treated with tenotomy and debridement showing 78% satisfied patients; according to his observations, teres minor atrophy worsens prognosis, and he considered pseudoparalysis and severe cuff arthropathy as contraindication.

3. Rotator cuff repair

When compared to other surgical techniques, arthroscopic repair seems to lead to the best results, at least from a clinical point of view [32, 33]. Nevertheless, even when the tear is repaired anatomically, it may have a low chance of healing. There are some factors that are related to tendon, such as the chronicity of the tear, the quality of the muscle, and the pattern and size of the tear that were proved to be associated to a low healing rate [34, 35, 36]. The healing of rotator cuff is additionally negatively influenced by other factors related to the age of patients and their comorbidities like smoking, hyperlipidemia, and diabetes [32, 37]. In conclusion, if we take into account the patient and its tendon-related factors, the ideal tear for repair is in a patient that still has a good joint space, with an X-ray that can be classified as Hamada 1 or 2, while clinical examination reveals preserved range of motion [32, 38, 39]. Massive tears in patients that present with pseudoparalysis that occurred in the last 6 months should be arthroscopically repaired as studies have proved that pseudoparalysis can be reversed [32, 39]. But, neglected pseudoparalysis or pseudoparalysis that appeared as a complication of a repair is less likely to recover into a good functional shoulder [32].

As emphasized above, it is generally agreed among surgeons that a complete repair of a massive cuff tear should tempt to completely restore the anatomic insertion of tendon to footprint, but in some patients, this goal cannot be achieved due to shortening of torn tendons, as muscles contract and retract quickly [40]. In such cases, a partial repair, although incomplete and not anatomic, can be tried [40]. Arthroscopic partial repair is advised in patients that are young and have a preserved structure of muscle with quite a low fatty infiltration that can be quantified using the MRI-based Fuchs classification [41]. In order to improve the functional results, these types of procedures can be performed together with a tendon transfer; depending on the location of the irreparable tear, the tendon used for transfer may be: latissimus dorsi or lower trapezius muscle fibers in case of posterosuperior tears; pectoralis major or sometimes latissimus dorsi in anterosuperior tears [40]. Arthroscopic partial repair and/or tendon transfer for MCT was proved to lead to satisfactory outcomes as claimed by quite a number of clinical studies [26, 40, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51].

Recently, a systematic review of the literature [40] was published; it inquired internet databases about studies dealing with arthroscopic repair of MCT; 55 studies have been identified, and 11 clinical studies were considered eligible, comprising 643 patients. Muscle strength was found to be significantly improved in all studies, while the functional range of motion was noted in the majority of cases [40]. Apparently, even a partial repair allows the shoulder to get balance and become less painful and more mobile [40, 52]. All these accomplishments are possible apparently with a low reoperation and complication rate [40]. Revision surgery had rarely to be performed because in case of repair failure, it was rather uncommon for the patient to complain about persistent pain [40]. So, as an intermediate conclusion, arthroscopic partial repair is a safe salvage solution [40]. Postoperative MRI or ultrasound found the retear rate to be about 50% [40]. The actual value of partial repair is challenged by this quite elevated risk of failure; much controversy is raised by the continuous improvement in symptoms and functionality even when the structural integrity of the repaired cuff is altered [40]. Lubiatowski [53] claims that clinical outcomes are not influenced by the preserved integrity of the repaired cuff [40, 53]. This finding might be explained by the increase of muscle strength after lavage, debridement, and synovectomy; consequently, there is less pain induced by muscle activity, so the status of repair would not matter anymore [26, 40, 54]. If the surgeon adds a decompression of suprascapular nerve, then the clinical outcome will significantly improve and will not be affected by the structural integrity of the repaired cuff [40, 55].

Nevertheless, there are some drawbacks to the previously mentioned studies [26, 40, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51] as the number of patients surveyed was quite small, the follow-up was widely variable, and long-term follow-up was not reported in any of the studies cited [40, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51]. With that being said, the value of arthroscopic partial repair technique needs to be proved by new studies dealing with the long-term patient outcomes [40]. Other negative aspects are that some papers dealt with heterogeneous populations characterized by different muscle structural anomalies such as fatty infiltration and by different sizes and numbers of tendon lesions [40, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51]. Finally, when we review the literature, even the type of the surgical procedure was not exactly the same as surgeons performed arthroscopic partial repair differently; some used a medialization of footprint in order to reduce tension of the repaired cuff [40, 56]; others were more conservative and applied margin convergence technique described by Burkhart [40, 57].

As an intermediate conclusion, we may say that arthroscopic partial repair might be an effective solution for contracted massive cuff tear, where an anatomic and complete repair cannot be achieved. The benefits are that it may improve strength and may improve the outcome of operation while restoring the muscle force couples, but it dramatically increases recovery if you treat it like a standard cuff repair; in old age populations where there is a low chance of healing, the question that is raised is: are you creating more morbidity? And last but not least, as mentioned before [40, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51], the quality of the available literature is low or at most moderate.

4. Mechanical and biological augmentation of rotator cuff repair

In order to promote and improve healing after partial/complete repair of massive cuff tears, various patch augmentation devices have been developed; according to the structure and origin of the graft, they may be synthetic extracellular matrix scaffolds, xenograft, and allograft [19, 58]. There are no clear recommendations for implanting scaffolds in rotator cuff surgery, but augmentation through the use of extracellular matrix patches is being investigated [19].

Scaffold augmentation is promoted because it can support mechanically the repair especially during the sensitive early phase of healing; other researchers state that they can also supply a network to accommodate the migrated cells that are mandatory for the healing process at the tendon-to-bone interface [19]. To this extent, synthetic scaffolds ensure structural and mechanical support and maintain the stability of the repair, gaining time until the tissue heals; they do not influence directly the biological environment at the repair [19, 59, 60, 61, 62].

The use of scaffolds derived from human dermis led to the improvement of shoulder scores and a better structural integrity of the repair, when implanted as an augment (85% in augmentation group vs. 40% in control group) [19, 61, 62, 63, 64, 65]; histologic samples from the repair site with augmentation showed no inflammation, infection, or calcifications at 3 months after surgery. But these scaffolds used for augmentation have a lower elasticity when compared to tendons, and therefore, theoretically, the repaired construct may have a higher tear rate [19, 60, 61, 62].

Extracellular matrix xenografts still pose the problem of immunogenicity despite adequate cell removal during the rigorous graft preparation process [60]; there are recommendations against these augmentation scaffolds, because in a high percentage of patients, important inflammatory responses have been signaled [19, 66, 67]. Other studies, like those conducted by Throckmorton and Gerlinger [19, 58], present favorable outcomes with dermal-origin scaffolds. Throckmorton and Gerlinger [19, 58] studies have also presented statistical information showing a decrease of clinical symptoms and an increase in function, strength, and shoulder scores.

Another graft option could be synthetic polymer implants that have no immunologic risk [19]. Synthetic extracellular matrix scaffolds proved to significantly increase the functionality of the repaired RCT [19, 58, 68]. A comparative study investigating patients with cuff surgery augmented by xenograft or synthetic graft noted retearing rates at 1-year follow-up of 51% and 17%, respectively, when related to 41% in patients with no augmentation [19, 60, 69].

Advanced research on the biology of healing of the rotator cuff tears, deep to the cellular level, even in augmented repaired cuff tears opened the path to new direct therapies [19]. Cellular growth factors applied at the repair site in animal studies induced neovascularization and cell proliferation [19]. However, the mechanical quality of the repair and tendon resistance to load did not improve according to these studies [19]. In another article, Cheung et al. [70, 71] stated that growth factors may enhance tendon-to-bone healing, in vivo.

The application of orthobiologics during arthroscopic rotator cuff repair has gained increasing clinical interest in the past decade, despite clear evidence studies; they are supposed to enhance tendon healing and improve clinical outcomes [72].

Platelet-rich plasma (PRP) is an autologous blood-derived fluid that contains growth factors; some of them are considered to be crucial in bone-to-tendon healing [19, 71]. The growth factors in PRP include an insulin-like growth factor-1, platelet-derived growth factor, vascular endothelial growth factor, and transforming growth factor-b [19, 73]. Theoretically, PRP at the repair site should promote healing, but there is controversy over its role because of contradictory results reported in the literature [60]. Many shoulder surgeons advocate that there is not enough evidence for the benefit of PRP biologic augmentation in any rotator cuff repair [19, 74, 75, 76, 77].

Ryan et al. [78] conducted a comprehensive systematic review and meta-analysis to determine the influence of different types of platelet-rich plasma as an augmentation procedure to rotator cuff repair; 17 studies were investigated, and the influence of leukocyte and platelet-rich plasma, leukocyte and platelet-rich fibrin, pure platelet-rich plasma (P-PRP), and pure platelet-rich fibrin was observed; the conclusion was that all types of PRP significantly reduce retear rate, especially when P-PRP is used [78].

In another study, Feltri et al. [79] looked at 36 randomized controlled trials and concluded that the augmentation with PRP reduces the retear rate but has no benefits on clinical outcomes; the same study [79] pointed out that PRP in patients treated conservatively failed to present any clear advantage.

Besides PRP, bone marrow aspirate concentrate (BMAC) has rapidly spread as an alternative biological therapy to augment tendon-to-bone healing.

Schoch et al. [72] investigated the effect of bone marrow aspirate concentrate (BMAC) and platelet-rich plasma augmentation on the rate of revision rotator cuff repair; the study included a total of 760 patients who underwent biological augmentation during rotator cuff repair — 646 patients with PRP and 114 patients with BMAC. They concluded that the application of BMAC led to a significant decrease in the rate of revision surgery, but there was no apparent effect of PRP.

But, Cole et al. [80] in a prospective randomized trial found out that BMAC-augmented arthroscopic repair of isolated supraspinatus tendon tears largely fails to improve failure rates and clinical outcomes when compared with simple arthroscopic repair.

Muench et al. [81] developed and published an arthroscopic technique biologically augmented with PRP, autologous subacromial bursa tissue, platelet-poor plasma (PPP), concentrated bone marrow aspirate, and bovine thrombin as stabilizer; a recent case series of patients treated with a very similar technique showed improvement in functional outcomes and quite a substantial clinical benefit [82].

Stem cells have multiple differentiation potentials, which stimulate tendon remodeling and increase biomechanical strength [83]. Additionally, stem cell-derived extracellular vesicles (EVs) can increase collagen synthesis while inhibiting inflammation and adhesion formation by carrying regulatory proteins and microRNAs [83]. Taking all that into account and reading all the literature available, stem cell-based therapy in rotator cuff repair seems to be the future, although basic clinical research is definitely required [83].

5. Superior capsular reconstruction

The superior capsule of glenohumeral joint spans from the superior labrum to the greater tuberosity of humerus; it covers the footprint of the supraspinatus tendon, and from a biomechanical point of view, it acts like a static stabilizer for the glenohumeral joint [19, 20, 84, 85, 86, 87].

Biomechanically, superior capsule reconstruction (SCR) can restore and thus regain balance of the force couples necessary for shoulder function [19, 20, 84]. Superior capsule is a static stabilizer that reduces the glenohumeral, allowing muscles like the deltoid and pectoralis major to function in proper conditions [19, 20, 84, 85, 87]. Superior capsular reconstruction is indicated in patients with irreparable tear of posterior superior cuff but with minimal or no glenohumeral arthritis (Hamada stage 1 and 2) and functional deltoid and trapezius; force couples should be balanced in the transverse plane, that is, intact teres minor and intact or reparable subscapularis, in other words—Type C and D according to Collin classification [34].

Mihata [85] observed the superior translation of humeral head, secondary increased acromiohumeral pressure, and associated low joint compression force while studying the biomechanical properties of glenohumeral joints with irreparable supraspinatus tears [85, 88, 89]. As an operative solution, he described the reconstruction of superior capsule (SCR) using a fascia lata as an autograft [85, 88, 89]. He fixed the fascia lata autograft to the scapular neck and the opposite side to the greater tuberosity; the interposed autograft would prevent the superior migration of the humeral head [19, 85, 88, 89, 90, 91].

Mihata [85] published excellent clinical results even in mid-term follow-up studies. The American Shoulder and Elbow Surgeons score increased from 29 preoperatively to 83 and 92 postoperatively after one year and five years, respectively; forward elevation increased from 85° preoperatively to 138° and 151° postoperatively after one year and five years, respectively; acromiohumeral distance also improved (preoperative—3.4 mm; one year postoperatively—9.1 mm; five years after surgery—8.1 mm) [19, 20, 91].

Harvesting fascia lata was linked to donor site morbidity and longer surgery times, so as a consequence, allogenic dermal allografts have been introduced. These allografts have been proven to act biomechanically like fascia lata to restore the humeral head position after a massive rotator cuff tear [19, 20, 92]. Burkhart et al. [19, 20, 93] used allograft reconstruction of superior capsule, and the published results are promising; in their series; they reported improvements of clinical outcome, quantified by American Shoulder and Elbow Surgeons and visual analog scale scores that increased from 45.6 to 85.8 and 5.26 to 0.96, respectively, at one year postoperatively [19, 20, 93].

Despite the relatively high costs of SCR with allograft (cost of dermal allograft and a large number of anchors used for appropriate fixation), SCR does not restore the active function of the supraspinatus muscle; therefore, some would consider these observations as drawbacks of the procedure. However, the technique still represents a viable treatment option in young and active patients who would not favor shoulder replacement [19, 20].

6. Other arthroscopic techniques for superior stabilization of humeral head

Recently, the long head of biceps tendon has been utilized in numerous surgical techniques to reconstruct the superior capsule [12, 13, 16, 22, 86, 94, 95]. These techniques are classified into techniques that reroute the tendon and techniques that use the tendon as a graft [19, 20]. All of these procedures require an intact long head of biceps tendon and seize the opportunity to harvest a locally available and viable autograft. In shoulders with intact long head of biceps tendon and intact glenohumeral cartilage, the use of biceps tendon for superior stabilization of the humeral head led to good clinical outcomes [19, 20].

Kim [17] published a technique that uses the long head of biceps tendon to perform in situ reconstruction of the superior capsule. In this technique, intraarticular biceps tenotomy is performed keeping the labral attachment intact; then, the freed end of tendon is fixed at the level of greater tuberosity; thus, biceps tendon pushes down the humeral head, reducing superior humeral head migration [19, 20].

Han [14] used seven fresh frozen shoulders to analyze from a biomechanical point of view this rerouting procedure; the results were promising, showing a stable shoulder as this rerouting technique successfully centers the humeral head into the glenoid cavity, thus reducing subacromial contact pressure and allowing for a functional range of motion [14, 19, 20]. To further support this technique, Sang-Yup Han [87] conducted biomechanical experimental studies on eight cadaveric shoulders and investigated the effects of biceps tendon rerouting with and without associated rotator cuff repair; the results reported a lower translation of humeral head, a more centered head with secondary reduced subacromial pressure, and no negative influence on the rotational range of motion [19, 20, 94]. When used in combination to arthroscopic cuff repair, this rerouting technique resulted in low retear rates and good clinical outcomes [15, 20, 96, 97]. However, data for an isolated biceps rerouting for massive irreparable rotator cuff tears are not available yet [15, 20, 96, 97].

Tang and Zhao [16, 19, 20] introduced a similar technique called arthroscopic dynamic rerouting; they created a new bicipital groove lateral to the native bicipital grove; the tendon is not attached at the level of greater tuberosity. Until now, clinical or biomechanical data have not been published [19, 20].

In a systematic review comparing superior capsular reconstruction techniques using long head of biceps tendon, Kitridis [93] arrived to the conclusion that these new biceps rerouting techniques were easy, time-efficient, and cost-effective [19, 20].

Denard [13] introduced another surgical technique that uses the biceps tendon in a box configuration; he supported his proposal with a biomechanical study on eight cadaveric shoulders. Apparently, in patients with massive rotator cuff tears, the technique did not restore the translation to previous range, although it decreased superior migration of the humeral head [13, 19, 20]. Clinical results for this technique have not been published yet [20]. Kim [17] proposed a variant of this technique that takes long head of biceps tendon with both its intraarticular and extraarticular parts and reconstructs the superior capsule; he referred to it as the Snake/Triple Bundle technique [17, 20]; the biceps tendon was sutured with tape, and an open subpectoral tenodesis was performed as an additional procedure. No clinical data have been reported yet [20].

Milano [98] used a semitendinosus tendon autograft and presented a surgical technique for superior capsular reconstruction. The semitendinosus tendon is harvested and debrided; then, it is armed with non-absorbable sutures; the graft is attached with anchors at the superior part of glenoid neck; the surgeon can create a box shape, V-shape, or reverse V-shape, depending on the graft length, and then attach it to the previously decorticated greater tuberosity [19, 20, 98, 99].

Bader and Garcia in 2020 [100] proposed the pivot superior capsular reconstruction fixation technique; it also uses a semitendinosus autograft that is shuttled through a hole in the scapular neck and then fixed in the greater tuberosity, preferably with an interference screw [19, 20, 100]. In 2021, Berthold [101] published a biomechanical cadaver study, investigating the best biceps and other graft rerouting surgical techniques; the results suggested that the V- shape and box-shape configurations significantly decreased superior humeral head migration and decreased deltoid cumulative forces [20, 101].

7. Biodegradable balloon

The subacromial spacer was approved by the US-FDA (Food and Drug Administration), for the treatment of MIRCTs, in 2021.

In 2012, in their studies, Romeo and Savarese [102] proposed the use of InSpace balloon, due to its simple and easy applicability technique [20, 102]. Consisting of poly-l-lactide-co-є-caprolactone, the pre-shaped InSpace spacer has an adsorption time of 1 year (12 months) [20, 102, 103, 104, 105]. As a surgical technique, the first step is the usual method of debridement and bursectomy, followed by positioning the biodegradable-type spacer through the lateral portal. Afterwards, a 0.9% saline solution is inserted, with the help of a Luer-Lock syringe, using the application system [20, 102]. The balloon size is proportional to the inserted volume of saline solution. Balloon sizing depends either on the tear and shoulder morphology or on the arthroscopic probe measurements, so their size varies, from small—40 × 50 mm, to medium—50 × 60 mm and large—60 × 70 mm [20, 102].

The long-term as well as mid-term outcomes and efficiency have been debated, due to the fact that the balloon is biodegradable within 1 year (12 months) [20, 98]. In a prospective study conducted by Familiari [103], 51 patients (mean age 63 – range 50–78 years old) were observed during a mean period of 36 months (24–56 months) [20, 103]. The results of Familiari’s prospective research showed improvement of Constant Score (CS) from 27 ± 7.4 up to 77 ± 15 (P ≤ 0.01). Furthermore, good to excellent scores were described in 46 patients, while five patients experienced unsatisfactory outcomes [20, 103]. Currently, in the existing literature, for the treatment options in massive irreparable rotator cuff tears, there are no comparative studies between other methods and InSpace Balloon technique [20].

8. Bursal acromial resurfacing

Based on the concept of subacromial spacer, in his study, Ravenscroft [106] proposed a special surgical technique, known as bursal acromial resurfacing (BAR). This procedure consists of an allograft—dermal-type, acellular—regarded as an option for irreparable rotator cuff tears [20].

Elderly patients (70 years old or over) presenting minimal or even no osteoarthritic evidences should benefit from this type of surgery. With the purpose of, on one hand, reducing the pain and, on the other hand, decreasing down to the minimum humeral head-acromion contact, as authors stated [20, 106], this surgical procedure should mix both grafts’ longevity, together with balloon simplicity. So far, no further evidence, such as clinical results, have been presented [20, 106].

9. Arthroscopic biologic inter-positional tuberosity graft

The greater tuberosity is a rare place for the dermal allografts to fail [107, 108]; instead, they usually fail within the graft’s mid-substance or at the glenoid level [20, 107, 108]. The clinical and imagistic study described by Mirazayan [109] showed that even failed dermal-type allograft superior capsular reconstruction relieves pain and improves functional outcomes [20, 109]; this observation could be explained by the so called “Biologic Tuberoplasty Effect” [20, 110].

As it is placed between the greater tuberosity and acromion, the graft is regarded as an interposition, biologic spacer, having a role in restricting the painful contact between these structures. Clinical outcomes for this type of procedures still require more studies and are not conclusive yet.