Intraoperative laxity measurements using a navigation system in anatomical double-bundle posterior cruciate ligament reconstruction.
OBJECTIVE
The objective of this study was to evaluate knee kinematics during double-bundle posterior cruciate ligament reconstruction (DB-PCLR) intraoperatively using a navigation system, and especially assess biomechanical behaviour of the anterolateral bundle (ALB) and posteromedial bundle (PMB) graft in DB-PCLR. Also, clinical results of minimum 2-year follow-up were investigated.


METHODS
Nine patients received DB-PCLR with hamstring graft. Before reconstruction, knee laxities, including posterior tibial translation (PTT) in neutral rotation at 15°, 30°, 45°, 60°, 75° and 90° of knee flexion, were measured using a kinematic-based navigation system. After the PMB or ALB was temporally fixed, the knee laxities were measured in the same manner. Each patient was evaluated pre- and post-operatively with side-to-side difference of tibial position in gravity sag view and Lysholm score.


RESULTS
Both ALB and PMB fixation restrained the PTT compared to  PCL deficiency throughout all knee flexion angles. At 90° of knee flexion, ALB fixation significantly decreased PTT compare to PMB fixation (p = 0.014) and DB-PCLR significantly decreased PTT compare to ALB fixation (p = 0.045). The mean side-to-side difference of tibial position in gravity sag view was 12.0 ± 1.7 mm preoperatively and 2.3 ± 1.8 mm at final follow-up, and the mean Lysholm scores were 68.9 ± 20.9 and 96.3 ± 2.9, respectively.


CONCLUSIONS
There were no significant differences in the PTT between ALB and PMB fixations at 0° to 75° of knee flexion, and both ALB and PMB reconstructions are important for restraining PTT. At 90° of knee flexion, the ALB grafts may be more important to control PTT compared to PMB grafts; however, neither single-bundle reconstruction with ALB nor PMB could function as DB-PCLR did. In addition, PTT after DB-PCLR was strongly correlated side-to-side difference in posterior sag view at the final follow-up. The results from this study indicated that both ALB and PMB are important to stabilize PCL-deficient knees.


METHODS
Therapeutic study, Level III.
Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Zaifu-cho 5, Hirosaki, 036-8562, Japan. yukax10@cc.hirosaki-u.ac.jp.
Yuka
Y
Kimura
Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Zaifu-cho 5, Hirosaki, 036-8562, Japan.
Eiichi
E
Tsuda
Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Zaifu-cho 5, Hirosaki, 036-8562, Japan.
Yasuharu
Y
Hiraga
Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Zaifu-cho 5, Hirosaki, 036-8562, Japan.
Yuji
Y
Yamamoto
Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Zaifu-cho 5, Hirosaki, 036-8562, Japan.
Shugo
S
Maeda
Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Zaifu-cho 5, Hirosaki, 036-8562, Japan.
Yasuyuki
Y
Ishibashi
D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007432:Intraoperative Period; D007718:Knee Injuries / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000379:methods*; D016119:Posterior Cruciate Ligament / Q000293:injuries / Q000601:surgery*; D019651:Plastic Surgery Procedures / Q000379:methods*; D025321:Surgery, Computer-Assisted / Q000379:methods*; D055815:Young Adult
Anterolateral bundle; Double-bundle reconstruction; Navigation system; Posterior cruciate ligament (PCL); Posteromedial bundle