Assessment of the rotator cable in various rotator cuff conditions using indirect MR arthrography

Prognostic Factors Leading to Good or Poor Outcomes Based on Functional and Radiological Findings After a Rotator Cuff Retear

BACKGROUND

A retear after rotator cuff repair is a common problem; however, there is little information related to the prognosis after a retear. In addition, some patients with retears have satisfactory outcomes, which raises the question of whether a retear leads to a poor prognosis.

PURPOSE

To identify radiological factors that influence the prognosis after a retear.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

A total of 51 patients with retears confirmed by magnetic resonance imaging at 1 year after arthroscopic rotator cuff repair with a minimum follow-up of 24 months were enrolled in this study. Patients were divided into 2 groups according to whether they achieved the minimal clinically important difference for clinical outcome measures. Range of motion and radiological variables, including preoperative and postoperative anteroposterior (AP) and mediolateral (ML) tear sizes, sagittal extent of the retear, acromiohumeral distance (AHD), and degree of fatty degeneration, were analyzed using magnetic resonance imaging.

RESULTS

Overall, 36 patients were allocated to the good prognosis (GP) group and 15 to the poor prognosis (PP) group. The 2 groups had no significant differences in baseline demographics and preoperative radiological parameters. Postoperative range of motion was decreased in the PP group at the last follow-up. The AP and ML retear sizes decreased in both groups after arthroscopic rotator cuff repair, but the retear size was significantly larger in the PP group (both P < .05). The AHD increased in the GP group (P < .001) but decreased in the PP group (P = .230) postoperatively. Logistic regression analysis revealed that postoperative AHD (P = .003), fatty degeneration of the infraspinatus tendon (P = .001), posterior (P = .007) and anterior (P = .025) sagittal extent of the retear, and change in the AP tear size (P = .017) were related to poor outcomes after a retear. However, change in the ML tear size (P = .105) and middle sagittal extent of the retear (P = .878) were not related to a poor prognosis. Also, further analysis showed that posterior (P = .006) and anterior (P = .003) sagittal extent of the retear were related to rotator cable involvement.

CONCLUSION

An increased AP retear size and decreased AHD were radiological parameters that were associated with poor clinical outcomes after a retear. In particular, patients who had posterior and anterior sagittal extent of the retear, possibly with rotator cable involvement and more severe fatty degeneration of the infraspinatus tendon, showed worse outcomes.

Distance between the supraspinatus and long head of the biceps tendon on sagittal MRI: a new tool to identify anterior supraspinatus insertion injury

PURPOSE

Anterior insertion of the supraspinatus muscle plays an essential role in rotator cuff tissue. We aimed to determine whether the distance between the midpoints of the supraspinatus central tendon and long head of the biceps tendon on a sagittal shoulder magnetic resonance imaging scan can help to preoperatively diagnose an injury of the anterior insertion of the supraspinatus.

METHOD

This retrospective study reviewed 103 patients with a full-thickness supraspinatus tendon tear: 50 patients with (injured group) and 53 patients without (intact group) anterior supraspinatus insertion tear. The inter-tendon distance was measured based on an oblique sagittal magnetic resonance imaging scan. SPSS was used for statistical analyses. Two independent samples t-test and receiver operating curve analysis were also performed.

RESULTS

The measurements of inter-tendon distance revealed good intra- and inter-observer reliabilities with intra-class correlation coefficients of 0.92 and 0.97, respectively. The inter-tendon distance of the injured group was significantly greater than that of the intact group (10.1 ± 2.7 vs 8.0 ± 2.3 mm, P < 0.001). The diagnostic ability of the inter-tendon distance was fair (area under the curve = 0.745), and a threshold of 9 mm had a specificity of 73% and sensitivity of 74%.

CONCLUSION

The distance between the supraspinatus central tendon and long head of the biceps tendon on magnetic resonance imaging was greater in patients with anterior supraspinatus insertion injury than those without the injury. A distance of 9 mm may be the cut-off value and a good diagnosis marker for anterior supraspinatus insertion injury.

LEVEL OF EVIDENCE

Level III, diagnostic case-control study.

[Partial-Thickness Tear of Supraspinatus and Infraspinatus Tendon Revisited: Based on MR Findings]

The interpretation of MRI of partial-thickness rotator cuff tears can be challenging. This review describes the anatomic considerations for diagnosing partial-thickness tears, especially supraspinatus and infraspinatus tendon and summarizes the classification of partial-thickness rotator cuff tears, as well as provides an overview on partial-thickness tears with delamination.

Locating the rotator cable during subacromial arthroscopy: bursal- and articular-sided anatomy

BACKGROUND

The rotator cable (RCa) is an important articular-sided structure of the cuff capsular complex that helps prevent suture pull out during rotator cuff repairs (RCRs) and plays a role in force transmission. Yet, the RCa cannot be located during bursal-sided RCRs. The purpose of this study is to develop a method to locate the RCa in the subacromial space and compare its bursal- and articular-sided dimensions.

METHODS

In 20 fresh-frozen cadaveric specimens, the RCa was found from the articular side, outlined with stitches, and then evaluated from the bursal side using an easily identifiable reference point, the intersection of a line bisecting the supraspinatus (SS) tendon and posterior SS myotendinous junction (MTJ). Four bursal-sided lengths were measured on the SS-bisecting line as well as the RCa's outside anteroposterior base. For the articular-sided measurements, the rotator cuff capsular complex was detached from bone and optically scanned creating 3D solid models. Using the 3D models, 4 articular-sided lengths were made, including the RCa's inside and outside anteroposterior base.

RESULTS

The RCa's medial arch was located 9.9 ± 5.6 mm from the reference point in 10 intact specimens and 4.1 ± 2.4 mm in 10 torn specimens (P = .007). The RCa's width was 10.9 ± 2.1 mm, and the distance from the lateral edge of the RCa to the lateral SS insertion was 13.9 ± 4.8 mm. The bursal- and articular-sided outside anteroposterior base measured 48.1 ± 6.4 mm and 49.6 ± 6.5 mm, respectively (P = .268). The average inside anteroposterior base measurement was 37.3 ± 5.9 mm.

DISCUSSION

The medial arch of the RCa can be reliably located during subacromial arthroscopy using the reference point, analogous to the posterior SS MTJ. The RCa is located 10 mm in intact and 4 mm in torn tendons (P = .007) from the posterior SS MTJ. If the above 6-mm shift in location of the RCa is not taken into consideration during rotator cuff suture placement, it could negatively affect time zero repair strength. The inside anteroposterior base of the RCa measures on average 37 mm; therefore, rotator cuff tears measuring >37 mm are at risk of rupturing part or all of the RCa's 2 humeral attachments, which if not recognized and addressed could impact postoperative function.

Interobserver reliability of the rotator cable and its relationship to rotator cuff congruity

BACKGROUND

This study evaluated the presence of the rotator cable intraoperatively and compared its prevalence according to both patient age and rotator cuff integrity. The study hypothesis was that the cable would be more prevalent in older patients and patients with partial-thickness tears.

METHODS

Patients who were undergoing shoulder arthroscopy and were aged at least 16 years were included in this study, whereas those who had a cuff tear of more than 1 tendon or who had a video with poor visualization of the rotator cuff insertion were excluded. Intraoperative videos were collected, deidentified, and distributed to 7 orthopedic surgeons to define rotator cable and cuff tear characteristics.

RESULTS

A total of 58 arthroscopic videos (average patient age, 46 years; range, 16-75 years) were evaluated. The observers were in the most agreement on identifying the presence of a cable, with a κ coefficient of 0.276. Patients with the rotator cable were significantly older than those without it (mean age, 52.1 years vs. 42.5 years; P = .008), and a positive and significant correlation was found between rotator cable presence and increasing patient age (r = 0.27, P = .04). A significant association was noted between tear degree and cable presence (P = .002). There was no significant association with cable presence in patients with a full-thickness tear.

CONCLUSIONS

In this study, an intraoperative analysis was performed to define the presence of the rotator cable and correlate this with both patient age and rotator cuff integrity. The hypothesis was confirmed in that patients older than 40 years had a significantly higher rotator cable prevalence.

Recent Issues in Musculoskeletal Anatomy Research and Correlation with MRI

MRI 영상은 관절 내 질환의 평가에 중요한 검사기법이며, 관절 MRI 영상의 해석을 위해선 견고한 해부학적 지식이 바탕이 되어야 한다. 관절의 해부학 분야에서는, 새로운 구조물이 발견되기도 하며, 과거에 보고되었으나 기능을 알지 못하던 구조물이 새롭게 주목을 받기도 한다. 본 종설에서는 최근 십여 년간 활발하게 연구되어온 견관절 회전근개 케이블(rotator cable) 및 상관절막(superior capsule), 슬관절의 후외측(posterolateral corner) 및 전외측 인대 복합(anterolateral ligament complex), 발목관절의 원위부 경비골 인대결합(distal tibiofibular syndesmosis) 등의 최근 연구 결과를 소개하고, 이를 MRI 영상을 통해 확인해 보았다.

Rotator cable in pathological shoulders: comparison with normal anatomy in a cadaveric study

The rotator cable is a semicircular thickening of the glenohumeral joint capsule. It travels between tubercles of the humerus and interweaves with the supra- and infraspinatus muscle tendons. The rotator cable anchors these tendons to the tubercles, playing the role of a suspension bridge. However, little is known about the modifications of this cable that result from pathologies to the rotator cuff tendons. Thus, we aim to compare the morphology of the normal rotator cable with cables in specimens with rotator cuff injuries. The glenohumeral joint was dissected in 30 cadaveric shoulders. The supra-, infraspinatus and teres minor muscles were inspected for injuries and the rotator cable was visualised. The cables course was determined and the width, length and thickness were measured. The rotator cable was found present in all cadavers dissected. In three specimens there was a partial injury of the supraspinatus tendon (two from capsular side and one from bursal side). The rotator cable was thickened in the cases of capsular tears. In another two specimens the supraspinatus and infraspinatus muscles were torn completely and in these cases the rotator cable was blended with retracted stumps and elongated to the level of the glenoid rim. The rotator cable creates a functional complex with the supra- and infrasinatus muscles. The morphology of the cable differs in cases of rotator cuff injury.

Systematic review of quantitative imaging biomarkers for neck and shoulder musculoskeletal disorders

Background

This study systematically summarizes quantitative imaging biomarker research in non-traumatic neck and shoulder musculoskeletal disorders (MSDs). There were two research questions: 1) Are there quantitative imaging biomarkers associated with the presence of neck and shoulder MSDs?, 2) Are there quantitative imaging biomarkers associated with the severity of neck and shoulder MSDs?

Methods

PubMed and SCOPUS were used for the literature search. One hundred and twenty-five studies met primary inclusion criteria. Data were extracted from 49 sufficient quality studies.

Results

Most of the 125 studies were cross-sectional and utilized convenience samples of patients as both cases and controls. Only half controlled for potential confounders via exclusion or in the analysis. Approximately one-third reported response rates. In sufficient quality articles, 82% demonstrated at least one statistically significant association between the MSD(s) and biomarker(s) studied. The literature synthesis suggested that neck muscle size may be decreased in neck pain, and trapezius myalgia and neck/shoulder pain may be associated with reduced vascularity in the trapezius and reduced trapezius oxygen saturation at rest and in response to upper extremity tasks. Reduced vascularity in the supraspinatus tendon may also be a feature in rotator cuff tears. Five of eight studies showed an association between a quantitative imaging marker and MSD severity.

Conclusions

Although research on quantitative imaging biomarkers is still in a nascent stage, some MSD biomarkers were identified. There are limitations in the articles examined, including possible selection bias and inattention to potentially confounding factors. Recommendations for future studies are provided.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-017-1694-y) contains supplementary material, which is available to authorized users.

Delaminated tears of the rotator cuff: prevalence, characteristics, and diagnostic accuracy using indirect MR arthrography

OBJECTIVE. The purpose of this study was to evaluate the prevalence, radiologic characteristics, and accuracy of diagnosing delaminated tears at the supraspinatus tendon-infraspinatus tendon (SST-IST) on indirect MR arthrography. MATERIALS AND METHODS. Of 531 consecutive shoulders that underwent indirect MR arthrography, 231 shoulders with tears at the SST-IST were included. On the MR images, delaminated tears at the SST-IST, defined as intratendinous horizontal splitting between the articular and bursal layers of the SST-IST with or without different degrees of retraction between the two layers, were identified and classified into six types. Other radiologic findings of the SST-IST, such as the presence of intramuscular cysts, were evaluated. We used video records of 127 arthroscopic surgeries to determine the diagnostic accuracy of indirect MRI for the detection of the delaminated tears at the SST-IST. RESULTS. On MRI, 56% (129/231) of shoulders with SST-IST tears had delaminated tears. Articular-delaminated full-thickness tears (n = 58) and articular-delaminated partial-thickness tears (n = 64) were the most common types. Approximately 82% (36/44) of articular-delaminated full-thickness tears occurring at the SST were combined with articular-delaminated partial-thickness tears at the IST. SST-IST footprint tears and intramuscular cysts were significantly more common in the shoulders with delaminated tears. The sensitivity and specificity of indirect MR arthrography for detection of delaminated tears were 92% and 94%, respectively. CONCLUSION. On indirect MR arthrography, approximately half of the shoulders with SST-IST tears had delaminated tears. The diagnostic accuracy of indirect MR arthrography for detection of delaminated tears was high.