Summary
The effects of three ACL reconstruction procedures - single-bundle (SB), double-bundle (DB), and single-bundle with lateral extra-articular tenodesis (SB+LET) - were compared in controlling pivot shift in a cadaveric experiment. The results showed that DB effectively reduced significant pivot shift, similar to SB+LET, while SB alone was insufficient.
Abstract
Purpose
Controlling significant pivot shift in knees with anterior cruciate ligament (ACL) injuries remains challenging using conventional reconstruction techniques. Recently, the addition of extra-articular procedures has gained attention as a potential solution, but comparisons between these techniques and double-bundle reconstruction regarding their effectiveness in controlling pivot shift are limited. This study aimed to quantitatively evaluate and compare the instability associated with three types of ACL reconstruction techniques in cases of ACL injuries with irreparable meniscal damage and significant pivot shift. Fresh cadaveric whole lower limb specimens and electromagnetic sensors were used for the evaluation.
Methods
Ten lower limbs from five fresh cadaver specimens were utilized to create four experimental models: ACL injury with irreparable meniscal damage and significant pivot shift (Group D), ACL reconstruction using the double-bundle technique (Group DB), ACL reconstruction using the single-bundle technique (Group SB), and single-bundle ACL reconstruction combined with lateral extra-articular tenodesis (LET) (Group SB+LET). After each surgical procedure, anterior tibial translation (ATT) during the Lachman test, ATT during the pivot shift test, and posterior tibial acceleration during the pivot shift test were measured and statistically analyzed.
Results
The ATT during the Lachman test was 13.5±2.4 mm for Group D, 7.4±1.6 mm for Group DB, 8.2±1.4 mm for Group SB, and 7.8±1.3 mm for Group SB+LET. The ATT during the pivot shift test was 5.8±2.6 mm for Group D, 3.1±2.3 mm for Group DB, 3.1±1.5 mm for Group SB, and 2.3±1.6 mm for Group SB+LET. All reconstructed groups demonstrated significantly reduced ATT compared to Group D (p<0.05), but no significant differences were observed among Groups DB, SB, and SB+LET (p>0.05). Posterior tibial acceleration during the pivot shift test was 2.7±1.4 m/s² for Group D, 1.4±1.2 m/s² for Group DB, 2.0±1.4 m/s² for Group SB, and 1.5±1.0 m/s² for Group SB+LET. Groups DB and SB+LET showed significantly lower values compared to Group D (p<0.05), while no significant difference was observed in Group SB (p>0.05).
Discussion
Meniscal damage is known to influence pivot shift in both ACL-injured and reconstructed knees. In this study, no differences in anterior instability were observed among surgical techniques; however, single-bundle reconstruction alone was insufficient to suppress pivot shift adequately. Double-bundle reconstruction or the addition of LET was necessary to achieve better control of pivot shift. These findings suggest that double-bundle reconstruction may provide superior initial knee joint stability in cases of ACL injuries with irreparable meniscal damage and significant pivot shift.
Conclusion
In cases of ACL injuries with irreparable meniscal damage and significant pivot shift, adequate suppression of pivot shift requires either double-bundle reconstruction or single-bundle reconstruction combined with LET.