Lésion isolée de l’infra-épineux à la jonction myotendineuse : une nouvelle lésion

PURPOSE

We have identified a previously unpublished lesion of the infraspinatus muscle at the myotendinous junction. We describe its presentation and MRI appearance, notably the absence of other tendinous pathology in the rotator cuff.

MATERIALS AND METHODS

We retrospectively reviewed 25 patients with isolated infraspinatus lesions and associated edema identified on the fat-suppressed T2-weighted images of MRI. Imaging exams and medical records collected over a 7-year period were reviewed by a team of radiologists and surgeons specializing in the shoulder. A presentation of the mechanism of injury, radiological analysis of MRI scans and other investigations (arthro-CT and EMG studies) were carried out; all MRI included at least two fat-suppressed T2-weighted (transverse and coronal) sequences and one T1-weighted (transverse) sequence.

RESULTS

The lesion was characterized by tearing or delamination at the myotendinous junction, which was accompanied by edema of the infraspinatus muscle in the initial phase. Over time the edema was seen to resolve and muscle atrophy and fatty degeneration became predominant. We identified two groups by the onset of their symptoms. In the "chronic" group (44%), onset was gradual, with these patients frequently having had one or more infiltrations at presentation to us. In the "acute" group (56%), there was an initial traumatic event that was variable in intensity and mechanism.

CONCLUSION

This isolated lesion of the infraspinatus at the myotendinous junction has not been previously described. It is recognized by its characteristic MRI appearance and is not generally seen on CT arthrograms as there is no communication with the joint. Its natural history appears to be of a progression from edema to fatty degeneration with or without myotendinous retraction and scarring. Its etiology has not yet been clearly established.

Critical analysis of the supraspinatus outlet view: rationale for a standard scapular Y-view

The supraspinatus outlet view has been standardized under fluoroscopic control to become reproducible and comparable; it is the normalized scapular Y-view. Four hundred four healthy shoulders from patients 20 to 80 years old and 63 shoulders with rotator cuff tears underwent x-ray evaluation and were compared. A qualitative study was carried out on the shape of the acromion in relation to Bigliani's types (I, II, III and on the presence or absence of a bony spur on the anterior part of the acromion. Quantitative measurements were determined; the subacromial peak and the spinoacromial angle were assessed for a statistical comparison among the various populations. The acromions of healthy shoulders varied with age (8% type III in patients younger than 60 years, 27% in those older than 60 years), although not significantly. The dominant side and sex of the subjects had no effect. With 29% type III acromions the shoulders with cuff tears differed from those of the healthy shoulders (14% type III). No close correlation was seen between type III acromions and cuff ruptures. The quantitative values of the acromions had no predictive value for cuff rupture. Acromion typology failed to confirm that a type III acromion was responsible for rotator cuff rupture. Spurs are found in increasing incidence with age and in the presence of cuff rupture; whether they are caused by subacromial impingement or by natural aging of the acromion is uncertain.

[Neer's shoulder prosthesis: results according to etiology]

The outcome of 80 glenohumeral arthroplasties with the Neer prosthesis in 77 patients with degenerative or inflammatory shoulder disease was evaluated after a mean follow-up of three years five months. The arthroplasties were performed because of intractable pain and functional disability due to destruction of the glenohumeral joint. The postoperative rehabilitation program focused on full recovery of joint motion and function in 65 cases and on joint stability with partial recovery of joint motion and function in 15 cases. According to the criteria developed by Neer, the outcome was excellent or satisfactory in 75% of cases and unsatisfactory in 25%. Constant's scores adjusted for age and gender varied widely across diagnostic categories, from a high of 76% in centered glenohumeral osteoarthritis (n = 40) to lows of 59% in rheumatoid arthritis (n = 21) and 45% in posttraumatic osteoarthritis (n = 10) or eccentric osteoarthritis due to cuff disruption (n = 9). At reevaluation, 70% of patients had little or no pain and 90% were satisfied with the outcome. The mean increase in flexion of the arm (39 degrees) was markedly influenced by the diagnosis. The increases in lateral rotation (mean 35 degrees) and medial rotation (four vertebral levels) of the arm were especially appreciated by the patients as having a very beneficial effect on the ability to perform everyday tasks. Complications included instability in three cases (two anterior dislocations and one posterior dislocation), glenoid component loosening in 11 cases (of which only four required reoperation) and rotator cuff tear in eight cases. Our results add to the existing evidence that nonconstrained shoulder implants, such as the Neer prosthesis, are both safe and effective in alleviating pain and improving joint function. They should be used in patients with refractory pain, disability due to restrictions in external and medial rotation of the arm and roentgenographic evidence of glenohumeral joint space loss.

[Postero-superior glenoid impingement. Another impingement of the shoulder]

An impingement occurring between the deep side of the supraspinatus tendon and the postero-superior edge of the glenoid cavity was evidenced in a young sports thrower presenting with a partial tear of the deep side of the tendon. This impingement occurred when the arm was in abduction-retropulsion and in forced lateral rotation. It was visualized on arthroscopy. The semiology was mixed, including signs of anterior instability and cuff impairment. The possible causes of partial tears of the deep side of the supraspinatus are discussed: sub-acromial impingement of NEER, anterior instability with secondary impingement, postero-superior glenoid impingement.

[2 roentgen projections for the subacromial space before and following acromioplasty. Results of a study series of 40 patients]

It is suggested that two radiological projections of the scapula, an AP view and a lateral (tunnel) view, be obtained in order to estimate the form and size of the acromion before and after acromioplasty. In order to evaluate the standardized films precisely, a film must have been taken for comparison before the surgery. As the method described is easily reproducible, it can be used to evaluate the effect of an acromioplasty irrespective of whether the procedure was an open or an arthroscopic one. The radiological results can be correlated with the functional results at the beginning of rehabilitation and at the end of this period. More sophisticated studies might require a more elaborate X-ray technique than the one proposed in this article.

[Surgical treatment of painful shoulders caused by lesions of the rotator cuff and biceps, treatment as a function of lesions. Reflections on the Neer's concept]

On the basis of their clinical and surgical experience of 480 shoulders operated upon for rotator cuff pathology, together with a review of the literature, the authors undertake a critical analysis of the Neer impingement syndrome. Since this syndrome cannot explain all lesions and above all cover all rotator cuff pathology, they suggest an anatomical classification based upon a description of lesions. They describe their indications for surgery on the basis of their results and of those from the literature.