Kouki NAGAMUNE

Lateral extra-articular tenodesis (LET) has been re-evaluated, and double-bundle (DB) anterior cruciate ligament reconstruction (ACLR) has also been used to provide greater rotational stability. The purpose of this study is to quantitatively compare the effects of single-bundle (SB) ACLR with LET and DB ACLR on knee joint stability in high-risk pivot-shift knees. Ten fresh-frozen cadaveric whole lower limbs were used under five conditions: (A) intact knee, (B) ACL-deficient knee with meniscal cut, (C) DB ACLR, (D) SB ACLR, and (E) SB ACLR with LET. Anterior tibial translation (ATT) during the Lachman test and posterior tibial acceleration (PTA) during the pivot-shift test were measured using an electromagnetic measurement system. ATT differed significantly among conditions (p < 0.01): (A) 6.8 ± 1.8 mm; (B) 13.3 ± 2.1 mm; (C) 7.6 ± 1.5 mm; (D) 8.0 ± 1.0 mm; and (E) 7.7 ± 1.1 mm (mean ± SD). (C), (D), and (E) significantly reduced ATT compared to (B) (p < 0.01). PTA differed significantly among conditions (p < 0.01): (A) 1.4 ± 1.2 m/s2; (B) 2.5 ± 1.0 m/s2; (C) 1.3 ± 0.9 m/s2; (D) 1.9 ± 1.2 m/s2; and (E) 1.4 ± 0.7 m/s2. (C) and (E) showed significantly improved rotational stability compared to (B) (p < 0.01 and p < 0.01), whereas (D) did not show a significant difference. SB ACLR alone did not significantly improve rotational stability. In cases with residual pivot-shift risk, either SB ACLR with LET or DB ACLR may be reasonable surgical options.