Evaluation of hamstring strength and tendon regrowth after harvesting for anterior cruciate ligament reconstruction.
BACKGROUND
It is generally thought that tissue regeneration and good functional recovery can be expected after anterior cruciate ligament reconstruction using the hamstring tendons. However, persistent strength deficit in deep knee flexion has also been reported.


OBJECTIVE
Morphologic regeneration of the harvested hamstring tendon is not necessarily associated with its functional recovery.


METHODS
Retrospective follow-up study.


METHODS
Twenty-eight patients who underwent anterior cruciate ligament reconstruction with hamstring graft were evaluated after a minimum period of 2 years. Status of tendon regrowth was assessed by magnetic resonance imaging. To specifically analyze the functional deficit after graft harvest, the isometric hamstring strength was examined in a sitting position at 90 degrees of flexion and a prone position at 90 degrees and 110 degrees of flexion. Then, the strength data were correlated with the extent of tendon regeneration.


RESULTS
In 22 of the 28 patients, a regrowth of the semitendinosus tendon was found, whereas regeneration of the gracilis tendon was observed in 13 patients. In the evaluation of hamstring strength, the isometric peak torque was reduced to 86.2%, 54.6%, and 49.1%, respectively, in the aforementioned 3 postures as compared with the contralateral side.


CONCLUSIONS
Significant functional deficit of hamstring strength remains regardless of morphologic regeneration.
Tadokoro
Kou
K
Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
Matsui
Nobuzo
N
Yagi
Masayoshi
M
Kuroda
Ryosuke
R
Kurosaka
Masahiro
M
Yoshiya
Shinichi
S
D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007718:Knee Injuries / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D018908:Muscle Weakness; D019637:Orthopedic Procedures; D019651:Plastic Surgery Procedures; D012189:Retrospective Studies; D013710:Tendons / Q000254:growth & development* / Q000637:transplantation*; D016896:Treatment Outcome; D016474:Weight-Bearing