Abstract
Background:
Subcoracoid cysts (ScCs) are often associated with rotator cuff tears, but their relationship with rotator cuff retears remains unclear.
Purpose:
To investigate the correlation between ScCs and retears in patients having undergone arthroscopic rotator cuff repair.
Study Design:
Cohort study; Level of evidence, 3.
Methods:
A retrospective analysis was conducted on patients who underwent arthroscopic rotator cuff repair from November 2016 to March 2022. Patients with Patte stage 1 or 2 tears were included. Preoperative magnetic resonance imaging (MRI) assessed subscapularis and supraspinatus tendons, biceps pulley, and ScC volume. Postoperative MRI evaluated the same parameters as preoperative MRI, with the addition of rotator cuff retear assessment. On the basis of preoperative MRI, patients were classified into group A (with cyst) and group B (without cyst). According to postoperative MRI, groups were further divided into A1 (without retear), A2 (with retear), B1 (without retear) and B2 (with retear). Postoperative decrease in ScC volume (ScC delta), Sugaya classification, and Constant score were compared.
Results:
The study included 109 patients: 69 in group A (A1 = 40, A2 = 29) and 40 in group B (B1 = 35, B2 = 5). The retear rate was significantly higher in group A (34.8%) than in group B (12.5%) (P = .02). In group A, the median (minimum-maximum) ScC delta value was significantly greater in group A1 (2422 mm3 [257 to 7503 mm3]) compared with group A2 (625 mm3 [–1060 to 1978 mm3]), indicating no recurrence of the ScC (P = .03). Postoperative Constant shoulder scores were higher in the no retear groups (group A1, 79.3 ± 8.2; group A2, 66.2 ± 13.4; group B1, 83.2 ± 8.5; group B2, 61.4 ± 5.9) (P < .001).
Conclusion:
For the patients with ScCs detected on preoperative MRI scans, preserved tendon integrity after rotator cuff repair was associated with a reduction in ScC volume. This reduction was evident on postoperative MRI scans when compared with preoperative measurements. Conversely, compromised tendon integrity did not lead to a significant reduction in ScC volume after surgery, potentially suggesting cyst reformation. Therefore, the postoperative identification of an ScC may indirectly indicate rotator cuff retear.
Keywords
The subcoracoid bursa is located below the coracoid process and conjoint tendon and anterior to the subscapularis muscle. 13 The subcoracoid bursa is related to the subacromial and subdeltoid bursae.3,10,25 On the other hand, it is not associated with the glenohumeral joint. 21 Fluid collection in the subcoracoid space represents a pathological process. 7 For an effusion to develop in the subcoracoid space, there should be fluid leakage from either the subacromial bursa or glenohumeral joint. 7 Many studies have reported that subcoracoid effusion is often associated with anterior rotator cuff tears involving the rotator interval.7,10,24,29,33,35 With the repair of tears and closure of pathways, a decrease in the volume of subcoracoid cysts (ScCs) is expected. 29 However, it is not well known whether ScCs reoccur or not after repair. Also, there are not sufficient data on the relationship between the integrity of these repaired tendons and the recurrence of the cysts.
Magnetic resonance imaging (MRI) of surgically repaired rotator cuff tendon is difficult to interpret. 4 In the first year after repair, rotator cuff appearance on MRI may be variable. This may include findings such as thinned appearance of the tendon or hyperintense signal within the tendon.4,23 In addition, evaluating rotator cuff tendon integrity may be difficult due to artifacts of the suture materials and implants. 16 In such cases, indirect findings may be useful for reaching a diagnosis. 16 From this perspective, the diagnostic value of ScCs in assessing the integrity of repaired rotator cuffs has been intriguing (Figure 1).
Patte coronal, stage 1 supraspinatus tendon tear with associated subcoracoid cyst and postoperative disappearance of the cyst along with preserved tendon integrity. (A) Preoperative magnetic resonance imaging (MRI) and coronal T2 section showing a Patte stage 1 supraspinatus tendon tear. (B) Postoperative MRI and coronal T2 section showing the presence of supraspinatus tendon integrity, classified as Sugaya stage 1. (C) Preoperative MRI and axial T2 section showing a subcoracoid cyst. (D) Postoperative MRI and axial T2 section showing no subcoracoid cyst recurrence.
The aim of this study was to investigate the relationship between tendon integrity and ScC volume changes in patients who underwent arthroscopic rotator cuff repair. The hypothesis of the study is that once the integrity of the rotator cuffs is restored, the ScC is not expected to reoccur. On the other hand, if there is tendon retear, the decrease in ScC volume will be minimal, as fluid leakage into the subcoracoid area will persist.
Methods
All procedures in this study involving human participants were conducted in accordance with the ethical standards of institutional and national research committees and with the 1964 Declaration of Helsinki and its subsequent amendments or equivalent ethical standards. No animals were used in the study. This study was approved by the ethics committee of İstanbul Medeniyet University Goztepe City Hospital. Informed consent was obtained from the participants.
In this retrospective, single-center, case-control study, patients who underwent arthroscopic rotator cuff repair between November 2016 and March 2022 by the same orthopaedic surgeon (İ.T.) and were previously studied were revisited. The inclusion criteria were patients aged >18 years; those with or without ScC; those with nonretracted anterosuperior rotator cuff tears of stage 1 or 2 in the coronal plane and segment 2,3 or 2 and 3 in the sagittal plane according to the Patte classification 22 ; those without other shoulder pathology; those who could be followed up during the postoperative period; and those who had a follow-up MRI in the postoperative period. Patients with Patte stage 3 coronal plane rotator cuff tears were not included in the study. Other exclusion criteria were patients with massive rotator cuff tears (tears ≥2 tendons), those with a history of previous shoulder operation, concurrent shoulder pathologies (frozen shoulder, calcific tendinitis, osteoarthritis, inflammatory arthritis, subcoracoid impingement, previous fracture), acute traumatic isolated subscapularis tendon tear, absence of postoperative follow-up MRI, or interrupted postoperative follow-up at 1 year.
Patients were divided into 2 groups according to the presence of ScCs on preoperative MRI: group A (with cyst) and group B (without cyst). Then, patients in groups A and B were evaluated via postoperative MRI to detect the absence or presence of retear based on the Sugaya classification, in which stages 4 and 5 were defined as retears 27 and further divided into 2 subgroups (group A1: without retear; group A2: with retear; group B1: without retear; group B2: with retear).
The demographic characteristics (age, sex, side), preoperative and postoperative Constant shoulder scores, 31 and intraoperative shoulder pathologies were noted via analyzing the examination notes, operative reports, and arthroscopy records of the patients. The timing of postoperative MRI in relation to the surgical procedure was also recorded. The data were gathered by an orthopaedic surgeon (M.A.).
Preoperative MRI scans of the patients were analyzed for ScCs, rotator cuff tears, fatty degeneration of the supraspinatus and subscapularis muscles, bicipital pulley damage, and other pathologies. Supraspinatus tendon tears were classified according to the degree of retraction in coronal sections and according to the location in sagittal sections as described by Patte. 22 Tears of the subscapularis tendon were investigated and classified as described by Lafosse et al 15 and Yoo et al. 34 Fatty degeneration of the supraspinatus and subscapularis muscles was investigated in sagittal T1 sections and classified according to the Goutallier description. 6 Biceps pulleys were evaluated via sagittal sectioning, and pulley lesions were analyzed according to the Habermeyer classification. 8
The integrity of the repaired cuff was evaluated via postoperative MRI. The rotator cuff tendon integrity was classified according to the Sugaya description. 27
ScCs were investigated via all preoperative and postoperative MRI scans. The cyst volume was calculated by the Cavalieri method. 29 Furthermore, the decrease in ScC volume at the postoperative MRI compared with the preoperative MRI (ScC delta) was calculated. The cross-sectional areas of the cysts on MRI were defined by manually drawing the outer border of the cysts on each axial section of the bursa in the T2 sequence using the “closed polygon technique.” The most proximal part of the bursa was noted as C1 (mm2), and the most distal part was noted as Cn (mm2). The distance between each section was taken as 4 mm, consistent with the MRI slice thickness in this study. The total cyst volume was calculated by the formula C1+C2+…. Cn) × 4 (mm3). 29 The measurements were performed by a senior shoulder surgeon and an orthopaedic surgeon (İ.T. and M.A.). The measurements obtained by the 2 authors were subjected to interobserver testing. The correlation between the 2 authors’ measurements was evaluated by the interclass correlation coefficients (ICCs) from replicability analyses. Agreement was considered excellent if the ICC was between 0.75 and 1, good if between 0.60 and 0.74, fair if between 0.40 and 0.59, and poor if below 0.40. The interobserver alpha value was 0.91.
Statistical Analysis
G*Power 3 (Heinrich Heine University) was used to determine the sample size. A minimum of 48 patients would be required in the study to determine the difference between the 2 groups (type I error [α] of .05 and power [1 –β] of 0.80).
The data were analyzed using IBM SPSS Statistics 18 software. The normality of the distribution of continuous variables was analyzed by the Kolmogorov-Smirnov test. Categorical variables in the study are presented as the frequency (n) and percentage (%), and continuous variables are presented as the mean ± SD, median (IQR, 25th-75th percentile) and minimum-maximum values. Pearson chi-square test, Fisher exact test, Yates correction, Fisher Freeman Halton exact test, and post hoc Bonferroni correction were used to analyze categorical variables. In independent 2-group analyses, the independent-samples t test was used for normally distributed data, and the Mann-Whitney U test was used for nonnormally distributed data. The Kruskal-Wallis test was used in the analysis of >2 independent groups that were not normally distributed. A statistical significance level of .05 was used in the study.
Results
Of the 376 patients, 230 were initially excluded from the study due to rotator cuff tear patterns that were either retracted or did not meet the criteria according to the Patte classification. Among the remaining 146 patients, 37 were further excluded: 13 because of superior labrum anterior to posterior lesions, 8 for previous fracture, 5 for subcoracoid impingement, 3 for a history of rheumatoid arthritis, 2 for acute traumatic isolated subscapularis tendon tear, and 6 for loss to follow-up. The study was conducted with the remaining 109 patients, with group A (patients with ScC) consisting of 69 patients and group B (patients without ScC) consisting of 40 patients (Figure 2). There were no significant differences between group A and group B in terms of age, sex, side, or preoperative Constant shoulder score (Table 1).
Flowchart of the study.
Demographic Characteristics, Classification of Rotator Cuff and Biceps Pulley Lesions, and Clinical Scores of Group A and Group B a
Data are presented as n (%) unless otherwise indicated. Bold value indicates statistical significance at P < .05.
Independent-samples t test.
Pearson chi-square test, Fisher exact test, post hoc Bonferroni correction.
Mann-Whitney U test.
There was no statistically significant difference between groups A and B in terms of rotator cuff tear pattern according to Patte, fatty degeneration of supraspinatus according to Goutallier, subscapularis tear according to Lafosse, and biceps pulley lesions according to Habermeyer (Table 1). A total of 8 patients with type 3 subscapularis tendon tears according to the Lafosse classification were treated with arthroscopic subscapularis tendon repair. Upon intraoperative evaluation, 79 patients underwent biceps tenotomy, and 6 patients underwent biceps tenodesis.
Postoperative MRI revealed that when the groups were categorized according to Sugaya types 1, 2, and 3 (without retear) and types 4 and 5 (with retear), the percentage of patients with retear (types 4 and 5) was significantly higher in group A2 compared to group B2 (Table 2). Additionally, postoperative Constant shoulder score was higher in group A1 compared with group A2 and in group B1 compared with group B2 (Table 3).
Evaluation of Groups on Postoperative MRI According to the Sugaya Classification a
Data are presented as n (%); P value calculated using Fisher's Exact Test. P < .05 was considered statistically significant, and is shown in bold.
Constant Shoulder Scores of Groups A1, A2, B1, and B2 a
Data are presented as mean ± SD. Bold values are statistically significant at P < .05.
Upon calculating the decrease in ScC delta of patients in group A, it was observed that the ScC delta value was significantly greater in the non-retear group (group A1) than in the retear group (group A2), indicating that the ScC did not recur in group A1 (Table 4) (Figure 3). On the other hand, only 3 patients in group B had ScC detected on postoperative MRI. Of these patients, 2 were type 2 and 1 was type 1 according to the Sugaya classification, and these patients belonged to group B1. However, this finding did not show a statistically significant relationship with tendon integrity.
Comparison of ScC Delta Values Between Group A1 and Group A2 a
Data are presented as median (minimum-maximum). Bold value indicates statistical significance at P < .05.
Mann-Whitney U test.
Supraspinatus tendon tear together with subcoracoid cyst and postoperative reappearance of the cyst with disruption of tendon integrity. (A) Preoperative magnetic resonance imaging (MRI) and coronal T2 section showing a Patte stage 1 supraspinatus tendon tear. (B) Postoperative MRI and coronal T2 section showing disruption of supraspinatus tendon integrity, classified as Sugaya stage 5. (C) Preoperative MRI and axial T2 section showing a subcoracoid cyst. (D) Postoperative MRI of an axial T2 section showing the reappearance of a subcoracoid cyst.
Sensitivity, specificity, and odds ratio (OR) of ScC as predictive of rotator cuff retear were calculated. Sensitivity was found to be 72% while specificity was 78% (OR, 3.73).
The interobserver reliability for the measurements was excellent, with an ICC of 0.91.
Discussion
The principal findings of this study indicate that in patients with ScC on preoperative MRI, a decrease in the volume of the ScC on postoperative MRI compared with preoperative MRI was correlated with the preservation of tendon integrity. However, if an ScC was not detected on preoperative MRI, the presence or absence of an ScC on postoperative MRI did not provide information about rotator cuff retear.
Rotator cuff retears are common, especially in degenerative cases, for which the prevalence is reportedly between 20% and 30%. 17 Retears lead to muscle atrophy, fatty degeneration, accelerated joint degeneration, and lower clinical scores. 20 Favorable functional outcomes and decreased pain have been reported after revision in patients with rotator cuff retears.1,2,14,18,19,30,32 Therefore, it is important to differentiate retears.
Classifications such as Owen, Hayashida, and Sugaya can be used in the evaluation of retears. 9 The Sugaya classification is frequently used to assess tendon integrity after repair, with type 3 being a partial retear and types 4 and 5 being total retears. 27 The interobserver reliability values of Sugaya type 3 are low, suggesting inadequacy in diagnosing retears. 9
Diagnosing rotator cuff retear can be challenging but is also crucial. Therefore, in deciding on a retear, it is sometimes necessary to utilize not only classifications but also supplementary findings. On this aspect, there are some indicative parameters described to determine rotator cuff retear. 26 The extent of fatty infiltration in the supraspinatus muscle, the degree of tendon retraction before surgery, and the acromiohumeral index are reported as significantly different in patients with retear. 26 Moreover, preoperative imaging has indicated that an anteroposterior tear size ≥40 mm, hyperlipidemia, and a critical shoulder angle ≥37° in combination are determining factors for retear, with 98% sensitivity and 86% specificity. 12 The tendon stump signal intensity may be related to retear as well. 11 According to a 5-year study, 5 acromial spur formation could be a predictive factor for rotator cuff retear. These findings are typically observed in the late term after the retear. However, based on this study, the presence of an ScC may serve as an early indicator of a rotator cuff retear.
Literature analysis revealed the lack of studies on ScCs. ScCs, or effusions, have traditionally been linked to rotator cuff tears. Although they have been mostly associated with supraspinatus tendon tears, they have also been notably associated with subscapularis tendon tears in recent years.7,24,28,29,35 Additionally, their correlation with biceps pulley lesions was established by Türkmen et al. 29 Consequently, a comprehensive review of the literature significantly supports the hypothesis that ScCs develop due to a deficiency in the rotator interval region, which is also the site of anterosuperior rotator cuff tears. In this study, the absence of cysts on postoperative MRI in patients within group B2 (who had no ScC on preoperative MRI and experienced a retear on postoperative MRI) does not fully prove these hypotheses but provides some support for them.
Although there are some studies on the relationship between ScCs and causative pathologies, whether there is a relationship between ScCs and rotator cuff retears has not been investigated before. In this study, it was attempted to emphasize this matter.
Limitations
The retrospective nature of the study, the relatively small number of patients, and the partially short follow-up period can be considered limitations of the study. Moreover, the outcomes of subsequent treatments for patients with retears were not included in this study as it was beyond the scope of this research. However, this topic may be addressed in future studies.
Conclusion
For the patients with ScC detected on preoperative MRI scans, preserved tendon integrity after rotator cuff repair was associated with a reduction in ScC volume. This reduction was evident on postoperative MRI scans when compared with preoperative measurements. Conversely, compromised tendon integrity did not lead to a significant reduction in ScC volume after surgery, potentially suggesting cyst reformation. Therefore, the postoperative identification of an ScC may indirectly indicate rotator cuff retear.
Footnotes
Final revision submitted January 4, 2025; accepted February 17, 2025.
The authors declared that there are no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.
Ethical approval for this study was obtained from the Clinical Research Ethics Committee of İstanbul Göztepe Prof. Dr. Süleyman Yalçın City Hospital (21.06.2023/2023/041).
