Isolated rupture of the subscapularis tendon

Sixteen consecutive patients were managed operatively for repair of an isolated traumatic rupture of the subscapularis tendon in the absence of avulsion of the lesser tuberosity. All of the patients were men. The diagnosis was made for each patient on the basis of the clinical examination and was confirmed by imaging studies and operative exploration. The operative treatment consisted of mobilization of the subscapularis after exploration and protection of the axillary nerve, transosseous reinsertion of the tendon to a trough created at the lesser tuberosity, closure of the rotator interval, and protection of the shoulder for six weeks postoperatively. The average duration of follow-up was forty-three months (range, twenty-four to eighty-four months). Thirteen patients subjectively rated the result as excellent or good. The average functional score of the shoulder, as assessed according to the system of Constant, was 82 per cent of the average age and gender-matched normal value. Active flexion was normal in twelve patients, was decreased by 15 degrees or less in three, and was severely limited in one patient. The capacity of the patients to work in their original occupations had increased from an average of 59 per cent of full capacity preoperatively to an average of 95 per cent postoperatively (p = 0.006). Operative treatment proved to be economically sound within the Swiss National Accident Insurance system. The quality of the result did not depend on the capacity for work at the time of the operation, on the type of work in which the patient was engaged, on the state of the biceps, or on the duration of follow-up. Conversely, the results were less successful when there was an increased delay from the time of the injury to the time of the operative repair

Deltoid muscle shape analysis with magnetic resonance imaging in patients with chronic rotator cuff tears

BACKGROUND: It seems appropriate to assume, that for a full and strong global shoulder function a normally innervated and active deltoid muscle is indispensable. We set out to analyse the size and shape of the deltoid muscle on MR-arthrographies, and analyse its influence on shoulder function and its adaption (i.e. atrophy) for reduced shoulder function. METHODS: The fatty infiltration (Goutallier stages), atrophy (tangent sign) and selective myotendinous retraction of the rotator cuff, as well as the thickness and the area of seven anatomically defined segments of the deltoid muscle were measured on MR-arthrographies and correlated with shoulder function (i.e. active abduction). Included were 116 patients, suffering of a rotator cuff tear with shoulder mobility ranging from pseudoparalysis to free mobility. Kolmogorov-Smirnov test was used to determine the distribution of the data before either Spearman or Pearson correlation and a multiple regression was applied to reveal the correlations. RESULTS: Our developed method for measuring deltoid area and thickness showed to be reproducible with excellent interobserver correlations (r = 0.814-0.982).The analysis of influencing factors on active abduction revealed a weak influence of the amount of SSP tendon (r = -0.25; p < 0.01) and muscle retraction (r = -0.27; p < 0.01) as well as the stage of fatty muscle infiltration (GFDI: r = -0.36; p < 0.01). Unexpectedly however, we were unable to detect a relation of the deltoid muscle shape with the degree of active glenohumeral abduction. Furthermore, long-standing rotator cuff tears did not appear to influence the deltoid shape, i.e. did not lead to muscle atrophy. CONCLUSIONS: Our data support that in chronic rotator cuff tears, there seems to be no disadvantage to exhausting conservative treatment and to delay implantation of reverse total shoulder arthroplasty, as the shape of deltoid muscle seems only to be influenced by natural aging, but to be independent of reduced shoulder motion

A modified rabbit model for rotator cuff tendon tears: functional, histological and radiological characteristics of the supraspinatus muscle

Background: A well-defined, reproducible small animal model that allows quantitative assessment of musculotendinous changes would be desirable for investigations concerning rotator cuff pathology. Methods: The supraspinatus tendon was released by osteotomy of the greater tuberosity in seven New Zealand rabbits. The musculotendinous unit was then allowed to retract during 6 weeks. Retraction was monitored with computed tomography (CT). At sacrifice, CT measurements of retraction were validated by measurement of the total length of the musculotendinous unit after sacrifice and by correlation with functional and structural properties of the musculotendinous unit at tendon release and at sacrifice. Results: Mean(SD) retraction of the musculotendinous unit was 1.8 (0.2) cm on CT, precisely, and negatively correlated with the total length of the retracted musculotendinous unit at sacrifice (r = −0.87, p = 0.011) but not significantly correlated with CT measurements of atrophy (r = 0.20, p = 0.699) or fatty infiltration (r = 0.13, p = 0.78). Mean (SD) muscle work decreased from 1.6 (0.23) Nm to 1.2 (1) Nm (p = 0.056). Mean (SD) muscle fibre diameter decreased from 65 (10) µm to 48 (16) µm (p = 0.063). This decrease was significantly correlated with the amount of fatty infiltration (r = 0.79, p = 0.033). Discussion: Tendon release using osteotomy of the rabbit greater tuberosity allows precise measurement of musculotendinous retraction and offers the possibility for functional muscular testing. Changes in the rabbit supraspinatus muscle caused by myotendinous retraction correspond to those observed in established sheep models