Magnetic Resonance Imaging Assessment of Acromion Morphology and Superior Displacement of the Humeral Head in the Impingement Syndrome |
Bon Seop Koo, Kyung Chul Kim, Jung Hee Oh |
Department of Orthopaedic Surgery, Kangbuk Samsung Hospital,
Sungkyunkwan University School of Medicine, Seoul, Korea |
충돌 증후군에서 견봉 형태 및 상완골 두 상방 전위의 자기공명영상 분석 |
구본섭, 김경철, 오정희 |
성균관대학교 의과대학 강북삼성병원 정형외과학교실 |
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Abstract |
Purpose : We studied magnetic resonance imaging of acromion morphology and
superior displacement of the humeral head in the patients with diagnosis of rotator cuff
impingement syndrome, and also documented the relationship of type Ⅲ acromion to the
rotator cuff tear.
Materials and Methods : We reviewed retrospectively 40 patients(40 shoulders) who
had arthroscopic treatment for the diagnosis of stage T impingement or rotator cuff
partial tear and did not have other risk lesions except acromion factor. The mean age
was 48.7 years at operation.21 men(21 shoulders), mean age of 26 years, were used as
controls. Acromial type, tilt, and superior displacement of humeral head in sagittal plane,
and acromial lateral angulation in coronal plane were measured. Four parameters of the
patients were compared with those of control group. And then, the data were subdivided
and analyzed with respect to acromial type and patient age in the impingement group.
Student t test and multi-way ANOVA were used. Results : In impingement group, Farley's type Ⅰ acromion, 33%, type Ⅱ, 38%, type
Ⅲ, 27% and type Ⅳ, 2%. Superior displacement of humeral head(4.8㎜) were
characteristic in the impingement group compared with the control group(1.3㎜)(p<0.05).
But acromial tilt and lateral angulation were not statistically different. In the analysis of
the impingement group, the change of 4 parameters was not significant with respect to
age(p>0.05), but lateral angulation in type Ⅰ acromion(18 degree) and superior
displacement of humeral head in type Ⅲ acromion(6.3mm) were significantly
increased(p<0.05). All 4 parameters were not different between two subdivided types of
type Ⅲ acromion. Conclusion : All types of acromion and large lateral angulation could develop
impingement syndrome, but acromial tilt was not risk factor. Appearance of type Ⅲ
acromion and increased superior displacement of humeral head were characteristic
findings in the impingement syndrome. Superior displacement of humeral head as a
result of degenerative change of rotator cuff was probably primary cause for
impingement. The type Ⅲ acromion might be an acquired form, which could be expected
to accelerate the tear of rotator cuff as a consequence. |
Key Words:
Shoulder, Impingement syndrome, Acromial morphology, Superior displacement of humeral head, Type Ⅲ acromion,
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