Regeneration of the Semitendinosus Tendon Harvested for Anterior Cruciate Ligament Reconstruction: Evaluation Using Ultrasonography

Abstract

In a prospective study, 40 consecutive patients who underwent anterior cruciate ligament reconstruction with doubled semitendinosus and gracilis tendon autografts were examined pre- and postoperatively by ultrasound to investigate the anatomy of the donor site before and after the harvest of the tendons. The patients underwent ultrasonography at 2 weeks and 1, 2, 3, 6, 12, 18, and 24 months postoperatively. A total of 298 postoperative sonographic evaluations were performed. The semitendinosus tendon was imaged in the sagittal and axial planes: structure and margins were evaluated with the sagittal views; thickness and width were measured with the axial views. In all cases the following sequence of healing was documented: 2 weeks after surgery the semitendinosus tendon site was occupied by an area of increased thickness and decreased echogenicity, suggesting the presence of traumatic edema of the soft tissue surrounding the tenotomy. At 1 month, an irregular hypoechoic structure appeared in a near-anatomic position; at 2 months after surgery, thickness, width, and cross-sectional area of this structure were significantly greater than preoperatively. The amount of regenerated tissue increased up to that seen in the tissue of the 6-month examinations, which also showed a more uniform echostructure. The scans performed at 1 year showed distinct edges and reduction in thickness and width. At 18 and 24 months the echogenicity of the structure occupying the donor site was very similar to that of the normal semitendinosus tendon. However, this structure was clearly identified about 4 cm proximal to the pes anserinus, revealing a more proximal insertion of the regenerated semitendinosus tendon.

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].…”

“…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. Moreover, sonography showed the trend of healing of the donor defect with hypertrophic tendinous tissue seen up to six months after surgery, while the ultrasound structure and measurements are consistent with normal tendon 12 to 18 months after surgery [19].…”

ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION & THE HAMSTRINGS Implications for injury prevention & rehabilitation

“…It should also be considered that ST tendon regeneration after ACLR may take approximately 18 months (Papandrea, Vulpiani, Ferretti, & Conteduca, 2000) and may not occur at all in 10 to 50 % of patients (Konrath et al, 2016;Nomura et al, 2015;Snow et al, 2012). Contrary to our hypothesis, there were no significant differences in eccentric knee flexor strength between surgical and control limbs, although there was considerable between-subject variability.…”

Lamberto Perugia Lecture. The Intuition and Contribution of Lamberto Perugia and His Fellows to Anterior Cruciate Ligament Reconstruction

“…Even in acute cases treatment of associated injuries can be performed uneventfully. Excellent functional recovery can be due to the potential for regeneration offered by the semitendinosus and documented by imaging, functional and histological studies (6)(7)(8). Another brilliant intuition of Professor Perugia was his use of peripheral plasties in place of or to support intra-articular reconstruction.…”