Quantitative Analysis of Muscle and Tendon Retraction in Chronic Rotator Cuff Tears

Abstract

BACKGROUND: Musculotendinous retraction is a limiting factor for repair of long-standing rotator cuff tears. However, it is currently unknown to what extent the muscle and tendon contribute to the degree of total retraction. Further understanding of this may possibly influence the strategy of musculotendinous reconstruction. PURPOSE: To analyze the contribution of muscle and tendon to the process of myotendinous retraction. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Magnetic resonance imaging of 130 shoulders with intact (n = 20) or completely torn supraspinatus tendons was analyzed. Fatty infiltration of the supraspinatus muscle was graded according to Goutallier stages. The degree of retraction of the tendon stump and of the musculotendinous junction was assessed. RESULTS: There were 30 shoulders without evidence of supraspinatus fatty infiltration, 25 with stage 1, 23 with stage 2, 25 with stage 3, and 15 with stage 4 changes. The corresponding tear sizes (distance of tendon end from greater tuberosity) were 4, 21, 27, 37, and 41 mm; the distance of the myotendinous junction from the greater tuberosity was 22, 33, 39, 48, and 48 mm; and the length of the tendons (distance of tendon end to myotendinous junction) was 19, 13, 12, 11, and 8 mm, respectively. In Goutallier stage 3 and above, and in case of a positive tangent sign, the musculotendinous junction was, in 90% of the cases, retracted to or beyond the glenoid. CONCLUSION: Musculotendinous retraction in chronic rotator cuff tears results mainly from shortening of the muscle fibers but in advanced stages results also from shortening of the tendon tissue itself. The present data demonstrate, for the first time, that the residual tendon stump in a tendon tear does not have the length of the original tendon and is further shortened over time. Therefore, direct anatomic tendon reinsertion will result in lengthening of the supraspinatus muscle greater than what it would have been before the tear. Background: Musculotendinous retraction is a limiting factor for repair of long-standing rotator cuff tears. However, it is currently unknown to what extent the muscle and tendon contribute to the degree of total retraction. Further understanding of this may possibly influence the strategy of musculotendinous reconstruction.

Factors affecting healing after arthroscopic rotator cuff repair

“…Muscle retraction can be defined by utilizing the position of the muscletendon junction (MTJ) in relation to landmarks on the scapula. Meyer et al [29] evaluated 118 shoulder MRIs for the MTJ position in the setting of a rotator cuff tear. They concluded that increasing stages of fatty infiltration correlate with increasing tear size, tendon shortening and MTJ retraction.…”

“…They concluded that increasing stages of fatty infiltration correlate with increasing tear size, tendon shortening and MTJ retraction. Initial stages of muscletendon unit retraction in the setting of rotator cuff tears with minimal fatty infiltration occurs through muscle shortening whereas tears with later stages of fatty infiltration shorten through tendon shortening [29] . Kim et al [30] reported similar results that showed with increasing tear size and tendon reaction, the tendon length shortens.…”

Strength, ROM, and ultrasound-detected healing rate after arthroscopic rotator cuff repair

“…Complications and poor functional outcome were rare in both groups, while the only two irreparable rotator cuff tears were in the degenerative group. This may be due to increasing retraction of the tendon stump over time [10], which was found to a greater degree in the chronic than in the traumatic group.…”

Arthroskopische Doppelreihenrekonstruktion bei Rotatorenmanschettenruptur

“…Abb. 1, [31,32]). Dies hat zur Folge, dass bei einer ausgeprägten Lateralisation der Sehne, eine übermäßige Spannung bzw.…”

“…ob die Voraussetzungen einer RM-Läsion eine anatomische Rekonstruktion überhaupt ermöglichen. Die Mehrheit der Sehnenläsionen sind degenerativer Natur und gehen mit einem primären Substanzdefekt der Sehne einher [18,31,34]. …”