2017 ISAKOS Biennial Congress Paper #93
Evaluation of Variety and Delamination of Infraspinatus Tendon Using Radial-Sequence Magnetic Resonance Imaging
Hiroshi Negi, MD, Hiroshima, Hiroshima JAPAN
Shin Yokoya, MD, PhD, Hiroshima, Hiroshima JAPAN
Katsunori Shiraishi, MD, Hiroshima JAPAN
Ryosuke Matsushita, Hiroshima, Hiroshima JAPAN
Yu Mochizuki, MD, Hiroshima JAPAN
Nobuo Adachi, MD, PhD, Hiroshima JAPAN
Mitsuo Ochi, MD, PhD, Higashi, Hiroshima JAPAN
University of Hiroshima, Hiroshima, JAPAN
FDA Status Cleared
Radial-sequence magnetic resonance imaging is useful for screening presence of posterosuperior lesion of infraspinatus tendon and delamination, and delamination itself may not influence the postoperative clinical results, range of motion and muscle strength of shoulder external rotation.
Magnetic resonance imaging (MRI) is useful for evaluating rotator cuff tendon lesions. However, posterosuperior lesion of infraspinatus tendon (PLIT) sometimes cannot be assessed because it is difficult to evaluate the PLIT by the conventional axial, coronal or sagital MRI. On the other hand, radial-sequence MRI (rMRI) was revealed to be useful for evaluating PLIT with the perpendicular evaluation against the cuff tendons. The purpose of this study is to evaluate PLIT using rMRI, and evaluated the sensitivity and specificity.
Material And Methods
This study included 81 patients had undergone arthroscopic rotator cuff repair (33 women and 48 men). We checked the rMRI taken before arthroscopic surgery. We evaluated the PLIT by the posterolateral slices of rMRI beneath the scapular spine. We classified the varieties of tendinous insertion. (Grade 0: no tear, Grade 1: partial tear, Grade 2: complete tear with delamination, Grade 3: complete tear without delamination nor contact of humeral head and spine of scapula, Grade 4: complete tear with contact of humeral head and spine scapula) Two orthopaedic surgeons evaluated the MRI, and defined Grade 1 and 2 as delamination on the MRI. We also evaluated presence of delamination to compare the arthroscopic findings blindly with the rMRI findings, and sensitivity, specificity, and kappa value were calculated. In addition, we also evaluated the correlation of classified varieties of tendinous insertion between the two doctors. Moreover we compared Constant score, retear rates, ranges of motion (ROM) in external rotation (ER) after surgery and strength index of ER which were defined as ratio of affected side divided by contralateral side between cases with and without delamination.
The average sensitivity of delamination was 78% and specificity was 62%. The presence of delamination on the MRI were correlated with arthroscopic findings (P<0.05) and kappa value was 0.38. The classification of varieties of tendon insertion was significantly correlated between two doctors (P<0.05 r=0.70). Constant score were 76.5±13.4 in delamination positive group and 73.2±17.5 in delamination negative group. Retear rate were 12% in delamination positive group and 20% in delamination negative group. Range of motion in ER were 53.8±17.2°in delamination positive group and and 56.9±20.3°in delamination negative group. Strength index of ER were 0.83±0.21 in delamination positive group and 0.84±0.33 in delamination negative group. There were no significant differences in Constant score, post operated occurrence of retear rate, ROM in ER and strength index in ER between with and without delamination.
Discussion And Conclusion
rMRI has high sensitivity of delamination presence of PLIT. So it may become a screening of PLIT delamination. But it has lower reproducibility so it may need proficiency. However, it has correlation to evaluating insertion of infraspinatus between surgeons. It may be useful to evaluate PLIT.
There were no significant differences in clinical results, ROM in ER and strength index in ER between with and without delamination. Delamination itself may not influence the postoperative results.