1 Introduction

Various methods for massive rotator cuff tears(MRCT) have been proposed, but MRCTs are still known as a challenging condition to treat. For irreparable cuff tears, various surgical techniques are widely used to improve functionality and relieve pain. These include tendon transfers (latissimus dorsi, pectoralis major, or lower trapezius transfer), as well as procedures like superior capsule reconstruction (SCR). These surgical approaches aim to address the challenges posed by the massive irreparable tears and offer potential benefits in terms of functional improvement and pain relief.^1–3

Among various surgical techniques, the use of allodermal graft in SCR is preferred and widely adopted because it allows avoiding donor site morbidity associated with autograft SCR using tensor fascia lata.^1,4 However, SCR has a drawback in that the surgical fixation of the allodermis graft from the scapula glenoid to the humerus greater tuberosity causes tension on the allodermis graft, making it difficult to avoid graft failure. Mirzayan et al. described that cases with graft failure but maintained humerus coverage showed similar satisfactory outcomes compared to patients with intact grafts, whereas patients with tear on the tuberosity side resulting in loss of tuberosity coverage had unfavorable results.^5,6

As a result, various methods have been introduced to minimize retear by avoiding graft tension in tendon transfer and SCR procedures. Recently, the arthroscopic biologic tuberosity (ABT) technique has been developed as an interpositional tissue graft technique, where the dermal allograft is fixed only to the greater tuberosity without tension, avoiding contact and irritation between the humerus and acromion. This approach has shown promising results and has been reported to yield satisfactory outcomes.^2,5,7

A similar interpositional tissue graft technique, bursal acromial reconstruction (BAR) has also been developed and introduced. In this technique, like ABT, an allodermis graft is used to fix the acromion undersurface, preventing contact and irritation between the humerus and acromion.^8,9 Ravenscroft et al. have argued that BAR serves merely as a spacer, thus recommending it for elderly patients aged 75 and above. For younger patients, they propose the SCR and BAR combination procedure, suggesting that simultaneous implementation of SCR and BAR would result in a double thickness effect of the graft, which could be advantageous in preventing humeral head depression.^8,9

As there have been no reported clinical outcomes of the combination of ABT and BAR to date, The objective was to analyze the clinical results of the combination of ABT and BAR. The hypothesis of this study was that the combination of ABT and BAR would reduce the retear rate and achieve an increase in acromiohumeral distance (AHD).

2 Method

After obtaining Institutional Review Board of our institution approval, a total of 18 cases who underwent simultaneous ABT and BAR procedures were retrospectively recruited as the study subjects (July 2020–August 2022).

Massive irreparable tears who had an normal or repairable subscapularis were included. The exclusion criteria included cases with irreparable subscapularis, a history of infection, those with joint arthritis classified as Hamada stage 3 or higher, and post-operative infection.

2.1

2.1 Surgical technique

First, large osteophytes around the greater tuberosity were removed using a burr, followed by a gentle decortication without aggressive measures. Subsequently, the tension-free repair positions of the anterior and posterior cuff tendons were checked, and the expected tuberosity area after repair was measured. A 40 mm × 50mm sized, 4 mm thickness acellular human dermal allograft (BellaCell; Hans Biomed Corporation, Daejeon, Korea) was prepared according to the measured size. On average, a graft size of 25 mm × 20 mm was measured.

Two Y-Knot® RC Anchor were placed on the greater tuberosity, and two PopLock or Argo knotless anchor (ConMed, New York, USA) on the lateral side were used to fix the acellular human dermal allograft using the suture bridge double row repair (Fig. 1). The remaining sutures from the two medial anchors were used to repair the anterior and posterior cuff tendons.

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Fig. 1 (A) Large osteophytes around the greater tuberosity were removed using a burr, followed by a gentle decortication without aggressive measures. (B) Two suture anchors were placed on the medial side, and two knotless anchor on the lateral side were used to fix the acellular human dermal allograft using the suture bridge technique.

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After completing the cuff repair and ABT procedure, the BAR was performed. To ensure proper graft attachment, a bleeding bed was created, and a flat acromioplasty was conducted. The size of the acromion undersurface was measured, and the remaining 4 mm acellular human dermal allograft (BellaCell; Hans Biomed Corporation, Daejeon, Korea) from the ABT procedure was utilized. On average, a graft size of 25 mm × 20 mm was used for the BAR. The anterior cromioclavicular joint portal, Neviaser portal, and posteromedial portal were used as medial shuttle portals by inserting a spinal needle. Fiberwires located at each corner were passed through the acromion and skin, and ties were performed to firmly secure them to the acromion undersurface (Fig. 2).

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Fig. 2 (A) To ensure proper graft attachment, a bleeding bed was created, and a flat acromioplasty was conducted. (B) The anterior cromioclavicular joint portal, Neviaser portal, and posteromedial portal were used as medial shuttle portals by inserting a spinal needle. Fiberwires located at each corner were passed through the acromion and skin, and ties were performed to firmly secure them to the acromion undersurface. (C) In the arthroscopic view after the combination of ABT and BAR, an allodermis graft fixed both above and below can be observed, leading to the expectation of a double spacer effect.

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2.3

2.3 Clinical and radiological evaluation

Before the surgery and at one year post-surgery, the researchers assessed the patients' VAS pain scores, ASES scores, and ROM. Forward flexion and external rotation were measured using a protractor. For internal rotation, the spine number that the thumb could reach was recorded.

Radiological evaluation was performed using plain radiography, magnetic resonance imaging (MRI), and sonography. Prior to the surgery and at one year post-surgery, plain radiography was used to measure the acromiohumeral distance (AHD, Fig. 3).³ At one year post-surgery, MRI and sonography were utilized to evaluate the integrity of the repaired structures. The outcomes were measured through assessments performed by an orthopedic specialist (J.W.J.), and Radiological evaluations were conducted with measurements taken twice by two observers, and the mean values were used for analysis (J.SY. and J.W.J.).

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Fig. 3 Plain radiography was used to measure the acromiohumeral distance.

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3 Results

Eighteen cases were recruited and observed for a minimum of 1 year. The average age was 62.1 ± 8.7 years, with a gender distribution of 7 males and 11 females. The mean tear size (anterior to posterior defect) was 3.2 ± 1.2 cm, and the mean retraction size (medial tolateral defect) was 3.1 ± 1.3 cm. The average Goutallier classification for the supraspinatus was 3.4, for the infraspinatus was 2.8, for the teres minor was 0.3, and for the subscapularis was 1.3 (Table 1).

One year post-surgery, both the VAS pain scores and ASES scores showed statistically significant improvement compared to before the surgery. The VAS pain score significantly improved from an average of 5.1 ± 2.4 before surgery to 1.7 ± 1.6 at one year post-surgery (p < 0.001). Similarly, the ASES score showed significant improvement, increasing from an average of 43.2 ± 21.6 before surgery to 87.9 ± 7.5 at one year post-surgery (Table 2).

The results showed statistically significant improvement in all directions of range of motion (ROM) when comparing pre-surgery and one year post-surgery data. Active forward elevation improved from 108.6 ± 48.1 before surgery to 158.4 ± 27.4 at one year post-surgery (p = 0.03). Active external rotation improved from 29.1 ± 32.1 before surgery to 50.1 ± 17.5 at one year post-surgery (p = 0.02). Active internal rotation also improved, moving from the L3 level before surgery to the L1 level at one year post-surgery (p < 0.001, Table 2).

Upon reviewing the radiological results, the AHD significantly improved from 4.3 ± 4.1 mm before surgery to 9.2 ± 1.9 mm at one year post-surgery (p < 0.001). Moreover, in the one year follow-up, there was no observed failure of the allodermis graft in any of the cases (Table 2. Figs. 4 and 5).

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Fig. 4 (A) A 55-year-old female patient was observed to have a irreparable massive rotator cuff retear on arthroscopic view. (B) First, a biologic tuberosity procedure was performed using an acellular human dermal allograft. (C) Subsequently, bursal acromial reconstruction was carried out using an acellular human dermal allograft. (D) On the preoperative MRI, findings of a massive rotator cuff retear and humeral head elevation were observed. (E) On the postoperative MRI, fixation of biologic tuberoplasty (arrow) and bursal acromial reconstruction (arrowhead) were observed, with a noticeable depression of the humeral head compared to the preoperative condition.

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Fig. 5 (A) A preoperative MRI of a 71-year-old female revealed findings of a massive rotator cuff retear. (B) On the postoperative MRI, fixation of biologic tuberoplasty (arrow) and bursal acromial reconstruction (arrowhead) were observed, with a noticeable depression of the humeral head compared to the preoperative condition. (C,D,E) At the 3-month postoperative mark, the patient exhibited a satisfactory recovery with no significant differences compared to the contralateral side in forward elevation, external rotation, and internal rotation.

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4 Discussion

MRCT is commonly known as a condition characterized by 2 or more cuff tendon tears with retraction extending to the glenoid and exhibiting Goutallier classification III or higher fatty degeneration. In such cases, repair is often deemed infeasible, and a high retear rate is observed.^10,11

To address this issue, various surgical techniques, such as muscle transfer, spacer insertion and superior capsule reconstruction (SCR), have been developed and reported. Among these approaches, SCR using allodermis graft has shown satisfactory results in restoring glenohumeral joint stability in cases of MRCTs.^4,12–15 Indeed, one of the drawbacks of surgical techniques that involve connecting the glenoid and humerus using tissue is the need for high tension to press the humeral head against the glenohumeral joint to maintain joint stability. This high tension can lead to complications, such as retear, when sufficient healing is not achieved. As a result, avoiding retear remains a challenge in these procedures.^5,6

Despite satisfactory clinical outcomes using Allodermis graft in SCR, high retear rates have been reported, and retears occurring at the tuberosity are closely related to poor clinical outcomes.^6,16 The issue of postoperative retear poses a challenge, as it can negatively impact patient satisfaction, even if patients are adequately informed about the possibility of retear before surgery and show satisfactory clinical results. Mirzayan et al. and others have compared and analyzed the retear pattern and clinical outcomes of SCR, reporting that the presence or absence of tuberosity coverage is closely related to clinical results.^5,6 Recently, tension-free graft techniques, such as biologic tuberosity, where the allodermis graft is fixed on the humeral side, or BAR, where the allodermis is tied to the acromion undersurface, have been developed and reported.^{5,7,8,17–19}

However, there is an ongoing debate regarding the appropriateness of the reported tension-free graft techniques as they align with the concept of a head depressor spacer, making them more suitable for younger patients where muscle strength recovery is crucial.^8,9 Ravenscroft et al. have argued that BAR serves merely as a spacer, thus recommending it for elderly patients and they propose the SCR and BAR combination procedure for younger patients.^8,9

In this study targeting Asian patients, the authors used an average graft size of 25 mm × 20 mm for greater tuberosity coverage and 25 mm × 20 mm for acromion coverage after partial cuff repair, making it possible to perform two procedures with a single graft of A 40 mm × 50 mm sized, 4 mm thickness acellular human dermal allograft (BellaCell; Hans Biomed Corporation, Daejeon, Korea). This not only offers cost benefits but also enhances the effectiveness of the spacer function. Regarding the combination of ABT and BAR, although there is a drawback of increased surgery time compared to the graft folding technique, the authors believe it is advantageous for healing since bone-to-graft healing can be expected separately for each technique.

Based on the evaluation of the study outcomes, the combination of ABT and BAR demonstrated statistically significant and satisfactory clinical improvements. The radiological outcomes also showed an increase in AHD and a decrease in the retear rate, which aligns with the hypothesis set in this study. This represents the significance of the first clinical radiological report on the results of the Combination ABT and BAR procedure.

This study is an analysis of the results of the combination of ABT and BAR, and it does not compare with groups where ABT or BAR was performed individually. Therefore, it is suggested that future research may require additional diverse comparative analysis studies. However, when BAR is performed individually, biomechanical studies have shown less satisfactory results compared to the intact cuff group, and SCR combined with BAR has demonstrated the most satisfactory outcomes in biomechanical studies.^8,9,20 Given that the ABT and BAR combination method is a tension-free fixation method, it is anticipated to minimize concerns regarding SCR retear while achieving superior biomechanical outcomes. This hypothesis, too, should be substantiated through further research.

In this technique, there was one case that met the exclusion criteria of postoperative infection. The patient was a 74-year-old female with uncontrolled underlying diabetes, which is a risk factor for infections. At 3 months post-surgery, signs of joint infection were observed, and the transplanted graft was removed, leading to exclusion from the study. Although this single case cannot provide statistical significance, it highlights the importance of being vigilant for infections, especially in immunocompromised patients, due to the longer surgery time and the transplantation of two grafts compared to conventional procedures. Combining ABT and BAR involves performing two procedures simultaneously, which may lead to an increase in surgical time compared to each procedure performed individually. However, when compared to SCR, the additional time required for glenoid fixation is eliminated, making the overall surgical time manageable.

5 Limitation

Firstly, it is a non-randomized, retrospective level IV case study, which may introduce bias and limit the generalizability of the findings. Secondly, the sample size is relatively not much, with only 18 cases included, which may affect the statistical power and limit the ability to draw robust conclusions, although a retrospective power analysis concluded that a minimum of 18 cases were required in each group to identify a 10 % difference between the groups, with an α level of 0.05 and β value of 0.80. Thirdly, the follow-up period is limited to one year, and a longer-term follow-up and randomized controlled study with a sufficient sample size would be beneficial to further evaluate the outcomes of the combination ABT and BAR procedure. Despite these limitations, this study holds significance as the first analysis of clinical and radiological outcomes for the combination ABT and BAR procedure. It provides valuable insights into the feasibility and effectiveness of this novel technique, laying the groundwork for future researches with sufficient sample numbers and longer follow-up.

6 Conclusion

The combination of ABT and BAR showed satisfactory clinical improvement, and the tension-free graft fixation technique resulted in a significant improve in AHD and a decrease in retear rates.

Ethics approval and consent to participate

This article does not contain any studies with human participants or animals performed by any of the authors. This study was reviewed and accepted by the Dankook University medical center Institutional Review Board.

Consent for publication

All of authors agree to publication.

Availability of data and material

It is available when reviewers request.

Competing interests

The authors declare that they have no conflict of interest.

Funding

There is no funding source.

Authors' contributions

J.B.S and J.S. Y. designed this study, J.S.Y. and J.W.J. took the radiologic measurements and gathered the retrospective data.