Contrast to our hypothesis, we found that the biceps tendon’s lower pressure during this tenodesis procedure was more successful in terms of healing compared to being under normal and high pressure.

The incidence of massive rotator cuff tears goes up with advancing age [7]. Especially in cases where treatment is delayed, severe muscle retraction and fatty degeneration of the muscles are observed. These factors have been described as irreparable tears due to the significantly increased risk of re-tear after repair [6]. Arthroscopic SCR and arthroscopic latissimus dorsi transfer (ALDT) are some alternative surgical procedure for this condition. Osti et al. reported that ALDT had shown a greater complication rate and less improvement in acromio-humeral distance [15]. However, research is still ongoing to determine the optimal graft for SCR and the optimal technique for graft application [8, 16]. A study reported that both graft preferences either autograft or synthetic allograft transplantation had satisfactory results [17]. In our study, we investigated the pressure level that the biceps tendon should have during tenodesis applied to the footprint of the rotator cuff while preserving the anchor of the biceps tendon in the superior glenoid for SCR. Since the effect of pressure values during biceps tenodesis on healing has not been previously investigated, our study will contribute to the literature and shed light on future studies.

Studies have shown successful results of biceps augmentation procedures in addition to rotator cuff repair in chronic rotator cuff tears [18]. In a study where biceps augmentation surgery was performed, patients experienced higher functional outcomes and rapid reduction in pain compared to the control group that underwent repair alone [19]. Another study used the biceps tendon as a free graft by tenotomizing it to avoid high tension during repair and demonstrated significant improvement in patient’s clinical scores and faster recovery of muscle strength in postoperative follow-ups [20]. Biceps tendon is preferred as an autograft in previous studies are the absence of the need for additional incisions, low cost, and no donor site morbidity [21].

Due to the numerous advantages over other graft types, we believe that the long head of the biceps tendon will continue to be frequently used for SCR. Therefore, we conducted our study using the biceps tendon to shed light on future studies. In our surgical technique, the biceps tendon functions as a dynamic stabilizer of the shoulder joint with mobility and lower pressure exposure in its natural localization in the bicipital groove. After tenodesis of the biceps tendon for SCR, it assumes a static stabilizer role and is subjected to a higher pressure than its natural state. We also believe that it cannot show flexibility against pressure due to limited mobilization. As a result, we found histological evidence of better healing with a lower pressure value measured in the groove compared to SCR performed with normal pressure or higher pressure.

A study demonstrated that SCR with augmentation of the biceps autograft improved glenohumeral stability and reduced subacromial peak contact pressure in irreparable supraspinatus tears [21]. A new technique was proposed to perform rotator cuff repair with biceps augmentation by creating a new bicipital groove without fixing the biceps tendon, allowing it to progress in the newly created groove for the SCR [22].

Particularly, there is a lack of studies on the level of pressure that should be applied by the graft to the repair area during the procedure. We observed a lack of consensus regarding the optimal application technique of the commonly used biceps tendon for SCR and the optimal pressure applied during the grafting procedure. In our technique we tenodesed the distal part of the biceps tendon to the footprint of the rotator cuff. One of the greatest advantage of this technique is that the proximal part of the biceps tendon is already naturally anchored to the superior glenoid.

In cases where the biceps tendon was used, greater improvement in acromiohumeral distance was observed, but there was no difference in the incidence of postoperative re-tear [23]. Due to better functional outcomes, it was recommended to perform SCR with the biceps tendon rather than using a fascia lata graft [8]. Most studies have highlighted the use of the biceps tendon as being more minimally invasive compared to the use of fascia lata graft, with no donor site morbidity. Follow-ups after surgical treatment have shown advantages in terms of clinical and radiological parameters compared to the use of fascia lata grafts [8, 23]. One of the main reasons for our preference for the biceps tendon in our study for SCR is its benefits over other autografts in the treatment of irreparable massive rotator cuff tears, and we believe it will be more commonly preferred in future research.

A study recommended that the technique of creating a patch from the biceps tendon, which will be used as an autograft, by meshing it with a meshing device, due to its high healing potential, low cost, and absence of donor site morbidity [24].

In our daily practice, a specific technique that has proven superiority over other techniques for SCR has not yet been established. In our study, we preferred the Chinese method technique, which describes the suture anchor fixation of the rotator cuff to the footprint after biceps tenotomy, due to its ease of application and the absence of the need for an additional incision [2]. In an acute massive rotator cuff tear created in a rabbit model, we demonstrated through histopathological evaluation that tenodesis the biceps tendon with lower pressure compared to normal significantly increased the success rate of biceps tenodesis for SCR, using a device called Flexiforce for pressure measurement. When the biceps tendon was in the bicipital groove and in a more mobile state with lower pressure exposure, the healing rates of tenodesis performed with normal or high pressure were significantly lower compared to those performed with low pressure, as the biceps tendon was subjected to higher pressure as a static stabilizer after the procedure. We assume that the pressure exerted by the graft during biceps tenodesis is important for the successful completion of the SCR procedure. We consider pressure measurement valuable to ensure proper graft healing and prevent complications.

Despite these findings, we have some limitations in our study. Firstly, since our study was conducted on an experimental animal population, there are biological differences between humans and these animals. Some of the differences include their shoulder joints being weight-bearing joints, having a high healing potential, and having relatively different shoulder anatomy. Therefore, these factors may affect our histopathological evaluation. And we also couldn’t use immunohistochemical evaluation for this study. Yet, we used the modified Bonar’s scale with all parameters for the evaluation of the healing. Additionally, since we applied an acute injury model in our study, the recovery of repairs applied in the treatment of rotator cuff tears caused by chronic degenerative pathologies in humans may not be the same. Furthermore, the use of the same species and breed in our study, along with the homogeneous distribution of groups and the prospective design, are strengths of our study.