Correlation between Passive Stretch and Active Contraction Distance and Characteristics of Musculotendinous Units...

Tendon reconstruction is a difficult procedure with unpredictable results, and evaluating and selecting the appropriate muscle tendon is crucial. To improve the results of tendon reconstruction, the authors investigated active muscle contraction during wide-awake local anesthesia no tourniquet (WALANT) surgery, in which the patient can perform active movements.

Among 213 WALANT tendon reconstructions, 148 muscle tendons were evaluated for active contraction distance and passive stretch distance of the muscle tendons, time elapsed before reconstruction, and characteristics and changes in muscle active contraction patterns after verbal instructions.

Active contraction and passive stretch distances showed significant positive correlations and flexor muscles displayed larger distances than extensor muscles. Time elapsed before reconstruction did not correlate with either distance. In the flexor digitorum superficialis muscle, active contraction distance was greater in the grip-related ulnar digits, but the late-phase pattern was more frequent. In the extensor indicis proprius muscle, contraction distance on instruction to extend the thumb was smaller than that when instructed to extend the index finger.

WALANT surgery is the only procedure in which active contraction distance and characteristics of muscle tendons can be observed intraoperatively, and it appears useful for tendon transfer.