Serial assessment of knee joint moments in posterior cruciate ligament and posterolateral corner reconstructed patients during a turn running task.

Introduction: During post-operative rehabilitation for posterior cruciate ligament (PCL) reconstruction, flexion is limited to 90° for the first 6 weeks, and hamstring strengthening is initiated at 3 months because of static stability. The posterolateral corner sling (PLCS) procedure is frequently performed with PCL reconstruction to help alleviate posterolateral rotator instability, and it is possible, during this procedure, to damage the dynamic motion and to over-constrain the knee.

Materials And Methods: For the patients group, PCL and PLCS reconstructions were performed simultaneously, and all reconstructed patients had stable knees and showed no complications. A motion analysis system was used to measure and calculate kinematic and kinetic data for seven patients after PCL and PLCS reconstruction (patients group) and seven normal subjects (control group) during a turn running task. The study was conducted on two groups at both 3 months (return to daily activity) and 6 months (return to light sports) post-operation. At 6 months after surgery, the dial test was also performed to observe the static rotational stability.

Results: Compared to the control group, the patients group showed a decreased extension moment (-1.15 ± 0.46 vs. -3.51 ± 0.69 Nm/kg, p = 0.000), a decreased valgus moment (-1.36 ± 0.72 vs. -2.15 ± 0.54 Nm/kg, p = 0.041) and a decreased external rotational moment (-0.15 ± 0.11 vs. -0.37 ± 0.10 Nm/kg, p = 0.002) 3 months post-operatively. However, these results approximated to the normal control, and the patients group showed an improved extension moment (-2.95 ± 0.67 Nm/kg, p = 0.188), valgus moment (-1.73 ± 0.58 Nm/kg, p = 0.359) and external rotational moment (-0.30 ± 0.09 Nm/kg, p = 0.325) at 6 months post-operatively. A static rotational stability revealed a similar or over-constrained state compared with the contralateral knee, and no patient showed rotational instability.

Conclusions: PCL-PLCS reconstructed patients were reluctant to engage in, or lacked strength for, daily rotational activities. Therefore, we must consider more active and systematic co-contraction exercise of the hamstring and quadriceps and rehabilitation program about rotation that is not adverse to the static stability in PCL-PLCS reconstructed patients for early return to daily activities.