[Coraco-humeral space and rotator cuff tears].
OBJECTIVE
The anterior or subcoracoïd impingement is often mentioned but remains unprecise as far as clinical, radiological or even anatomical lesion are concerned. The purpose of our work was to study the different factors influencing the subcoracoïd space in case of cuff tear.


METHODS
Our study was based on 206 shoulders operated for full-thickness rotator cuff tear. The SubCoracoïd Space (SPS), measured in millimeters on pre-operative arthro-CT-scan, was defined by the shortest distance between the coracoïd process and the humeral head. Muscular statement of the rotator cuff componants was graded according to Goutallier's and Bernageau's classification. According to literature data, we chose "6 mm" value as an inferior limit for normality. Shoulders were dispatched into three groups: group 1 was composed of supraspinatus +/- infraspinatus tears (59 cases), group 2 was composed of isolated lesions of the subscapularis (57 cases) and group 3 was composed of large cuff tears (supraspinatus +/- infraspinatus) involving also the subscapularis (90 cases).


RESULTS
There was a statistically significant relationship between SCS narrowing, duration of symptoms and the non-traumatic onset. When there was no subscapularis lesion (group 1) the mean SCS was 9 +/- 2 mm, in 3 cases the SCS was inferior to 6 mm. In group 2 (isolated lesion of the subscapularis), the results were similar with 9 mm as an average and 3.5 p. 100 SCS inferior to 6 mm. On the contrary, in group 3 we found the major percentage of SCS inferior to 6 mm (27 p. 100) with an average of 7.7 +/- 3.5 mm. The long head of the biceps had no influence on the SCS. There was a strong statistically significant relationship between SCS size and fatty degeneration of the subscapularis muscle (p < 10-4) and infraspinatus muscle (p = 0.0004). Eventually, there was a statistically significant correlation between the subcoracoïd space and the sub acromial space.


CONCLUSIONS
Measurements of the SCS in isolated lesions of the subscapularis show that the coracoïd process is not the mechanical factor responsible for tendon rupture. SCS narrowing is the consequence of a large cuff tear involving both the subscapularis and the infraspinatus tendon. Subscapularis tear is a necessary but not a sufficient condition by itself for SBS narrowing. Complete tear of the infraspinatus tendon and above all the muscular degeneration of the infraspinatus muscle is the other necessary condition for SCS narrowing. The horizontal control of the humeral head depends on subscapularis-infraspinatus muscular balance control. According to Patte's hypothesis SCS narrowing corresponds to an horizontal anterior translation of the humeral head due to fatty degeneration of subscapularis and infraspinatus muscle.
Nové-Josserand
L
L
Clinique Saint Charles, Lyon.
Boulahia
A
A
Levigne
C
C
Noel
E
E
Walch
G
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography; D017006:Rotator Cuff / Q000000981:diagnostic imaging / Q000473:pathology*; D000070636:Rotator Cuff Injuries; D013708:Tendon Injuries / Q000000981:diagnostic imaging / Q000473:pathology*