Impingement

 

MZ twinsa (N = 30b)

DZ twinsa (N = 28c)

p value

Age (year)

63.66 ± 4.32 (53–72)

63.78 ± 1.96 (60–66)
 
 Female

62.40 ± 6.3 (53–72)

63.77 ± 2.03 (60–66)

0.264

 Male

64.30 ± 2.86 (61–71)

63.80 ± 1.83 (61–66)

0.978

Acromiohumeral distance (mm)

10.13 ± 1.70

9.69 ± 1.74

0.197


aThe values are given as the mean and standard deviation, with or without the range in parentheses

b10 female and 20 male

c18 female and 10 male




Table 2
Summary of acromiohumeral distance heritability analysis














































MZ twins

DZ twins
 
 
p value of mean squares
   
p value of mean squares
   

Mean difference (mm)

Within pairs

Among pairs

ICC

Mean difference (mm)

Within pairs

Among pairs

ICC

Heritability

−0.13

<0.001

0.450

0.91

0.10

<0.001

0.849

0.50

0.82


MZ monozygotic, DZ dizygotic, ICC intraclass correlation coefficient



Table 3
Acromiohumeral distance (AHD) differences according to occupation





































 
Monozygotic twins

Dizygotic twins

Occupation

AHDa (mm)

p value

AHDa (mm)

p value

HMW

10.25 ± 1.88

0.842 vs. ASW

9.55 ± 1.89

1.00 vs. ASW

ASW

9.88 ± 2.30

1.00 vs. PW

9.60 ± 0.80

1.00 vs. PW

PW

10.60 ± 1.31

1.00 vs. HMW

9.80 ± 1.79

1.00 vs. HMW


HMW heavy manual workers, ASW administrative support workers, PW professional workers

aThe values are given as the mean and standard deviation


The resulting heritability index showed genetic factors to be the main cause of the variability of the acromiohumeral distance, with shared and unique environmental factors contributing only slightly to the variability.

The role of genetic factors is also supported by the results of the acromiohumeral distance comparisons of the three groups of workers. No significant differences were found among groups who performed or had performed different types of labor. This was confirmed both in the whole study cohort and within the monozygotic and dizygotic subjects. These data appear to be partially in contrast to those of Frost and Andersen [51], who observed that shoulder-intensive work was a risk factor for impingement syndrome. Analogously, van Rijn et al. [52] noted that highly repetitive work was associated with the occurrence of subacromial impingement, and Roquelaure et al. [53] observed that skilled blue-collar workers were more likely to develop subacromial impingement, especially if forced to abduct the arm repeatedly. Finally, in a longitudinal study, Svendsen et al. [54] showed that forceful work, work with elevated arms, and repetitive work each doubled the risk of surgery for subacromial impingement.

Our study suggests that the anatomical features that influence the width of the subacromial space are mainly genetically determined. However, if the subacromial space is already constitutionally narrow, external factors would strongly contribute to further reduction of the space, making it too tight. This might occur as a consequence of the ossification of the acromial insertion of the coracoacromial ligament [9]; of contracture of the posterior capsule of the glenohumeral joint, which would lead to upward migration of the humeral head [5557]; or of scapular muscle performance deficits [58].



Rotator Cuff Integrity in Patients with Antique Unilateral Upper-Limb Amputation


In order to test the role of the extrinsic factors in the genesis of the rotator cuff tear, we evaluated by an MRI exam, both shoulders of 25 patients with antique unilateral upper-limb amputation (Fig. 1a, b).

A369816_1_En_14_Fig1_HTML.gif


Fig. 1
Evaluation of active shoulder flexion (a) and abduction (b) in a 72 years old male with a right upper-limb amputation


Rotator Cuff Tendon Status (Structural and Qualitative Condition) According to Sugaya Classification [59] and Rotator Cuff Muscle Tropism According to Fuchs Classification [60]


Oblique coronal, oblique sagittal, and axial T2-weighted spin-echo MRI images were obtained in all subjects. Coronal oblique shoulder images were in plane parallel to the supraspinatus tendon. The patients were examined in the supine position with the arm at the side, the palm facing up, and the hand under the hip in order to keep the shoulder motionless. The acromiohumeral distance (AHD) of both shoulders was also measured in the participants with full thickness cuff tear. The AHD was calculated in coronal oblique projection as the distance between the most caudal point of acromion lower surface and the most cranial point of proximal humerus.

The results are summarized in Tables 4 and 5 Gumina S, 2015. Table 4 shows the healthy status of rotator cuffs in the studied group according to Sugaya classification. The general tendency showed not significant repartitions between the amputated and the healthy side (p = 0.18). When each shoulder was separately evaluated, a significant prevalence of Sugaya type II category in the amputated side (χ 2 = 12.5, p = 0.02) and of Sugaya type I category in healthy side (χ 2 = 25.5, p < 0.001) was found. Considering only the 19 participants with no rotator cuff tear, the mean values of the AHD of the amputated and healthy side were 0.81 cm (SD: 0.11) and 0.87 cm (SD: 0.13), respectively; thus, a significant difference was found (p = 0.02).


Table 4
Distribution of the sample according to Sugaya classification



































 
Amputated side

Healthy side

Type I

7 (28 %)

13 (52 %)

Type II

10 (40 %)

7 (28 %)

Type III

4 (16 %)

2 (8 %)

Type IV

1 (4 %)

1 (4 %)

Type V

3 (12 %)

2 (8 %)
 
χ 2 = 12.5, p = 0.02

χ 2 = 25.5, p < 0.001


The hypothesis was that the two repartitions were identical



Table 5
Distribution of the sample according to Fuchs’ classification
































 
Amputated side

Healthy side

p-valuea

Type 0


1(4 %)

0.033

Type I

8 (32 %)

13 (52 %)

Type II

7 (28 %)

8 (32 %)

Type III

5 (20 %)

1(4 %)

Type IV

Only gold members can continue reading. Log In or Register to continue

Stay updated, free articles. Join our Telegram channel

Jul 14, 2017 | Posted by in ORTHOPEDIC | Comments Off on Impingement

Full access? Get Clinical Tree

Get Clinical Tree app for offline access