Le conflit latéral de l'acromion

The lateral subacromial impingement is based on the assumption that the lateral acromion is the causal constitutional factor of the subacromial pathology and consequently of the rotator cuff tears. The lateral acromion provides to the deltoid a predominant ascending force as soon as its overhang is important. The rotator cuff suffers, the humeral head tends to rise and the coraco-acromial arch receives higher stresses, causing morphological changes and especially a traction enthesophyte. Thus, with age as well as with professional constraints, the acromion lengthens and curves. This is the acquired part of the problem, responding to the initial extrinsic theory of the subacromial impingement. The contact between the coraco-acromial arch and the rotator cuff, which is normally physiological, then becomes symptomatic. The acromion can be responsible for the aggression to the cuff and especially to the supra-spinatus tendon. This latter is the most exposed to the pressure against the acromial coraco-acromial arch when the humeral head is going up. This original concept of lateral impingement of the acromion shuffles the indications of acromioplasty, as well as the technical modalities of its realization as it was recommended until now.