Locations of lesser tuberosity cysts and their association with subscapularis, supraspinatus, and long head of the biceps tendon disorders

Is it the subcoracoid impingement or the subacromial impingement that tears the subscapularis tendon? A comparison of the MRI findings of the operated and healthy shoulders of the patients

BACKGROUND

: The purpose of this study is to investigate whether the etiological factors accepted as causes of idiopathic subscapularis tears are true or not when the comparison is made with the opposite side healthy shoulder of the patients who underwent arthroscopic repair for an isolated subscapularis tear.

METHODS

Sixteen patients who underwent shoulder arthroscopy between February 2016 and January 2018 and were diagnosed with isolated subscapularis tear were evaluated. The coracohumeral distance (CHDax), coracoid overlap (CO), and tuberculum minus cysts (TMC) were evaluated on the axial images of the MRI studies while the acromiohumeral distance (AHDsag), CHDsag, and subscapularis tendon slip number (STSN) on the sagittal oblique images and the AHDcor and SLAP lesion on the coronal oblique images. Degeneration of the coracoacromial ligament was evaluated during arthroscopy.

RESULTS

The mean CHDsag (11.26-10.08), CHDax (10.63-9.98), CO (14.2-15.43), AHDsag (8-7.66), and AHDcor (7.65-7.68) measurements (operated side-healthy side, respectively) were statistically similar (p > 0.05). No statistically significant difference was found between TMC and STSN in healthy and operated shoulders (p > 0.05). There was mild coracoacromial ligament fraying in 4 (25%) and obvious coracoacromial ligament fraying in 8 (50%) which indicated subacromial impingement in 75% of the patients.

DISCUSSION

The parameters of the coracoid process did not reveal any significant difference between the operated (for an isolated subscapularis tear) and opposite-side healthy shoulders of the patients. However, coracoacromial ligament degeneration was present in 75% of the patients.

Predicting the clinically significant subscapularis tendon tear: malposition and tear of the long head of the biceps tendon on shoulder magnetic resonance imaging

BACKGROUND

The diagnostic accuracy of magnetic resonance imaging (MRI) is low for detecting a subscapularis tendon tear.

PURPOSE

To identify MRI findings that may predict the presence of a clinically significant subscapularis tendon tear requiring surgical repair.

MATERIAL AND METHODS

We reviewed shoulder MR images of patients who had undergone arthroscopic rotator cuff repair at our institution between June 2018 and May 2019. Patients were divided into two groups: the study group (n = 51), with an intermediate- to high-grade partial thickness tear of the subscapularis tendon suspected on preoperative MRI and intermediate or higher grade of the tendon tear proven on arthroscopy; and the control group (n = 18), with an intermediate- to high-grade partial thickness tear of the subscapularis tendon suspected on preoperative MRI but no tear or low-grade partial thickness tear of the tendon shown on arthroscopy. Preoperative MR images were retrospectively evaluated by two readers for the size of the subscapularis tendon tear, bone reactions at the lesser tuberosity, and long head of the biceps tendon (LHBT) pathology.

RESULTS

The subscapularis tendon tear measured by reader 2 was larger in the study group than in the control group. The prevalence of a tear (P = 0.006 for reader 1; P = 0.011 for reader 2) and malposition (P < 0.001 for both readers) of the LHBT were significantly greater in the study group.

CONCLUSION

A tear and malposition of the LHBT on MR images may predict the presence of a clinically significant subscapularis tendon tear.

Evaluating subscapularis tendon tears on axillary lateral radiographs using deep learning

OBJECTIVE

To develop a deep learning algorithm capable of evaluating subscapularis tendon (SSC) tears based on axillary lateral shoulder radiography.

METHODS

A total of 2,779 axillary lateral shoulder radiographs (performed between February 2010 and December 2018) and the patients' corresponding clinical information (age, sex, dominant side, history of trauma, and degree of pain) were used to develop the deep learning algorithm. The radiographs were labeled based on arthroscopic findings, with the output being the probability of an SSC tear exceeding 50% of the tendon's thickness. The algorithm's performance was evaluated by determining the area under the receiver operating characteristic curve (AUC), sensitivity, specificity, negative predictive value (NPV), and negative likelihood ratio (LR-) at a predefined high-sensitivity cutoff point. Two different test sets were used, with radiographs obtained between January and December 2019; Test Set 1 used arthroscopic findings as the reference standard (n = 340), whereas Test Set 2 used MRI findings as the reference standard (n = 627).

RESULTS

The AUCs were 0.83 (95% confidence interval, 0.79-0.88) and 0.82 (95% confidence interval, 0.79-0.86) for Test Sets 1 and 2, respectively. At the high-sensitivity cutoff point, the sensitivity, NPV, and LR- were 91.4%, 90.4%, and 0.21 in Test Set 1, and 90.2%, 89.5%, and 0.21 in Test Set 2, respectively. Gradient-weighted Class Activation Mapping identified the subscapularis insertion site at the lesser tuberosity as the most sensitive region.

CONCLUSION

Our deep learning algorithm is capable of assessing SSC tears based on changes at the lesser tuberosity on axillary lateral radiographs with moderate accuracy.

KEY POINTS

• We have developed a deep learning algorithm capable of assessing SSC tears based on changes at the lesser tuberosity on axillary lateral radiographs and previous clinical data with moderate accuracy. • Our deep learning algorithm could be used as an objective method to initially assess SSC integrity and to identify those who would and would not benefit from further investigation or treatment.

Lesser tuberosity cysts and their relationship with subscapularis tears and subcoracoid impingement

BACKGROUND

We aimed to evaluate cysts in the lesser tuberosity of humeral head seen on magnetic resonance imaging (MRI) and their relationship with subcoracoid impingement and subscapularis tears evident on arthroscopic surgery videos. Our hypothesis was that the cysts would be more frequent with subscapularis tears and in the case of subcoracoid impingement.

METHODS

Patients who underwent shoulder arthroscopy between January 2010 and January 2016 were retrieved to evaluate subscapularis tears on surgery videos and lesser tuberosity cysts (LTC), coracohumeral distances (CHD) on both sagittal oblique and transverse sections of MRI retrospectively. There were 137 patients meeting the study criteria with subscapularis tear evident on surgery video and having preoperatively studied magnetic resonance images. All the tears were classified according to the Lafosse's system. The control group was constituted with 121 patients who underwent shoulder arthroscopy and were diagnosed with no subscapularis tear. Then, any statistically significant relationship between these parameters was investigated by the use of statistics software.

RESULTS

The mean age (57), gender distribution (female for 67.1%), and involved shoulder (right for 62.8%) rate of the groups were statistically similar. The existence rate of LTC was 55.5% and 19% for the study and control groups, respectively (P = .000). The study group was then evaluated in two groups regarding the existence of a cyst in the lesser tuberosity. There was no statistical difference between these two groups in terms of coracohumeral distances and tear type (P > .05). The study group was also divided into two depending on the transverse section CHD whether it was under 7 mm or not. There was still no statistical difference between these subgroups in terms of a cyst existence (P > .05). The supraspinatus tear rate and age distribution was also not differing in patients with and without LTC.

CONCLUSIONS

The LTCs were significantly associated with subscapularis tears, and could be used as an indicator in the interpretation of MRI scans. However, there was no relationship between the subcoracoid impingement and LTCs.