Abstract
Background: A morphology change at the back side of acromion may occur after arthroscopic rotator cuff repair and this change is advocated as knot impingement. It is considered that physical irritation by the kont against the back side of acromion causes knot impingement. The purpose of this study was to investigate the knot of anchor which has the potential to be a cause of knot impingement.
Materials: We studied 10 patients with small or capsuler side rotator cuff tear, which were repaired by one anchor with two high strength sutures. There were 4 males patients 6 females patients, with a mean age of 60.1 years (range, 23 to 78 years). 3D-CT was performed immediately, 4 weeks, 8 weeks and 12 weeks after operation.
Results: The insert locations were antero-lateral (5 shoulders), postero-medial (1 shoulder), postero-lateral of superior facet (3 shoulders) and antero-lateral of middle facet (1 shoulder). In 2 of 3 shoulders, an anchor was inserted at the postero-lateral location of the superior facet, knot impingement occurred. Acromioplasty was performed in these two shoulders.
Conclusion: The knot of anchor, which was inserted at the postero-lateral portion of the superior facet, could represent knot impingement.
