Reporting rotator cuff tears on magnetic resonance arthrography using the Snyder's arthroscopic classification

AIM To determine diagnostic performance of magnetic resonance arthrography(MRA) in evaluating rotator cuff tears(RCTs) using Snyder's classification for reporting.METHODS One hundred and twenty-six patients(64 males, 62 females; median age 55 years) underwent shoulder MRA and arthroscopy, which represented our reference standard. Surgical arthroscopic reports were reviewed and the reported Snyder's classification was recorded. MRA examinations were evaluated by two independent radiologists(14 and 5 years' experience) using Snyder's classification system, blinded to arthroscopy. Agreement between arthroscopy and MRA on partial-and fullthickness tears was calculated, first regardless of their extent. Then, analysis took into account also the extent of the tear. Interobserver agreement was also calculated the quadratically-weighted Cohen kappa statistics.RESULTS On arthroscopy, 71/126 patients(56%) had a fullthickness RCT. The remaining 55/126 patients(44%) had a partial-thickness RCT. Regardless of tear extent, out of 71 patients with arthroscopically-confirmed fullthickness RCTs, 66(93%) were correctly scored by both readers. All 55 patients with arthroscopic diagnosis of partial-thickness RCT were correctly assigned as having a partial-thickness RCT at MRA by both readers. Interobserver reproducibility analysis showed total agreement between the two readers in distinguishing partial-thickness from full-thickness RCTs, regardless of tear extent(k = 1.000). With regard to tear extent, in patients in whom a complete tear was correctly diagnosed, correct tear extent was detected in 61/66 cases(92%); in the remaining 5/66 cases(8%), tear extent was underestimated. Agreement was k = 0.955. Interobserver agreement was total(k = 1.000).CONCLUSION MRA shows high diagnostic accuracy and reproducibility in evaluating RCTs using the Snyder's classification for reporting. Snyder's classification may be adopted for routine reporting of MRA.

Accuracy of shoulder joint injections with ultrasound guidance:Confirmed by magnetic resonance arthrography

BACKGROUND Intra-articular glenohumeral joint injections are essential procedures for treating various shoulder disorders. Fluoroscopy-guided injections have been extensively used;however, they pose a risk of radiation exposure and are expensive and timeconsuming. Recently, it has been suggested that ultrasound-guided injections are accurate and cost effective procedures.AIM To evaluate the accuracy of ultrasound-guided glenohumeral injections using a posterior approach that is confirmed using magnetic resonance arthrography(MRA).METHODS The study included 179 shoulders of patients with recurrent anterior instability(150 patients;103 and 76 right and left shoulders, respectively;160 males and 19 females;average age = 20.5 years;age range: 14-63 years) who underwent MRA for preoperative diagnosis. They were injected with 12 m L lidocaine(1%) using the ultrasound-guided posterior approach and then underwent magnetic resonance imaging. Two shoulder surgeons, except for the injector, evaluated the transverse relaxation(T2)-weighted images of axial planes and classified the intraarticular condition of injected contrast into three groups based on one of the three following scenarios: no leakage, injection into the glenohumeral joint without leakage;minor leakage, practical intra-articular injection with some leakage outside the posterior rotator cuffs;and major leakage, inaccurate injection with mass leakage without any contrast into the joint. The inter-rater reliability between two assessors was also evaluated by calculating Cohen’s kappa coefficient. The learning curve was assessed regarding the inaccurate injection rate by analyzing Spearman’s rank correlation coefficient.RESULTS Of the 179 injections, 163 shoulders(91.0%) had no leakage, 10 shoulders(5.6%) had minor leakage, and six shoulders(3.4%) had major leakage. In total, 173 shoulders(96.6%) were intraarticularly injected;thus, we could detect anterior labrum and capsular pathologies. Regarding the inter-rater reliability, the kappa coefficient was 0.925, indicating consistency in the evaluations by both examiners. Regression analysis of the inaccurate injection rate for assessingtechnical learning showed a logarithmic curve with a downward trend(R;= 0.887, P < 0.001). Three(50%) of the six inaccurate injections classified into “major leakage” were observed in the first 30 injections, indicating that the accurate injection showed a leaning effect.CONCLUSION Ultrasound-guided intra-articular glenohumeral injections using a posterior approach had high accuracy;however, injection accuracy depends on clinical experience.