Hamstring tendons regeneration after ACL reconstruction: an overview

Abstract

Despite the long lasting research the ideal method of reconstructing the ACL has not been found so far. The last year's attention has shifted to the use of the multistrand hamstring tendon grafts. High ultimate tensile load, multiple-bundle replacement that better approximates the anatomy of the normal ACL and low donor site morbidity are the main advantages of this ACL replacement graft. These theoretical advantages have been multiplied when surprisingly studies have shown that semitendinosus and gracilis tendons actually regenerate after harvesting for use as ACL autografts. In this review article we summarize the current knowledge concerning the hamstring regeneration and we focus on issues that have clinical relevance or issues that have not been answered so far.

Semitendinosus tendon regeneration after anterior cruciate ligament reconstruction: can we use it twice?

“…If only the ST ST semitendinosus tendon was harvested with an intact G tendon, neotendon developed in 18 (72 %) cases, and then the insertion site was mostly below the joint line but above previous pes anserinus site, in 15 (83.3 %) of the legs. Our ultrasound findings are in agreement with findings from imaging studies in which the regenerated ST tendon seemed to insert more proximally on the gastrocnemius fascia rather than on the tibia, as does the native ST tendon [5,6,[17][18][19][20][21]. This different insertion pattern of the regenerated tendon could explain how it acts mainly as a flexor muscle rather than as a flexor and internal rotator [22][23][24].…”

“…We agree that the surgical procedure must be as non-traumatic as possible in order to preserve normal vascular anatomy of the harvesting area and the expected regeneration process [18]. Secondly, our study shows that when the G tendon is left intact, the ST tendon regeneration was more successful in 72 % of cases compared to 60 % when the G tendon was harvested in addition.…”

“…The scheme of tendon regeneration after surgical removal is still unsolved, and we do not really know which of two proposed repair mechanisms, the extrinsic, the intrinsic, or both, is the most realistic [7,17,18]. The process of regeneration investigated by ultrasonography in our study and suggested by the sonography findings in the other studies confirmed that fibrillary tendon-like tissue seems to fill the site originally occupied by the ST tendon.…”

Anterior Cruciate Ligament Mechanoreceptors Regeneration Following Reconstruction Using Autografts

“…Many research papers have demonstrated the regeneration of the tissues, in the area that provides these autografts [9][10][11][12][13][14][15][16][17].…”

Operative treatment for the painful posterior thigh after hamstring autograft harvesting

“…The ST is known to regenerate relatively well after the harvesting, forming a so called neotendon 3 . However, sometimes the regeneration process of the neotendon is disturbed which causes pain, weakness and cramping to the posterior thigh [4][5][6][7][8][9] . The reasons for the compromised healing of the neotendon are not well described in the literature earlier, although the cause for chronic posterior thigh pain might be too early started and rapid progression in postoperative physiotherapy or a new injury to the posterior thigh after harvesting 10 .…”