Gender differences in knee kinematics during weight-bearing knee flexion for patients with arthrofibrosis after anterior cruciate ligament reconstruction

Effectiveness of an intelligent weight-bearing rehabilitation robot in enhancing recovery following anterior cruciate ligament reconstruction

Aim

Orthopedic surgery patients frequently delay early rehabilitation due to postoperative discomfort. This is especially true for younger patients with anterior cruciate ligament injuries who are eager to return to sports after discharge. Despite the recognized benefits of early rehabilitation, a standardized protocol for determining safe weight-bearing timelines post-ACL reconstruction is lacking. This study aims to evaluate the effectiveness of an Intelligent Weight-Bearing Rehabilitation Robot in improving recovery outcomes for these patients.

Design

A retrospective cohort study comparing outcomes between individuals who received the intervention and those in the control group.

Methods

Ninety-two patients who underwent ACL reconstruction were chosen as subjects and separated into two groups: control and intervention, each with 46 patients, in the order of hospital admission. The control group got standard rehabilitation training, whereas the intervention group received rehabilitation training using the Intelligent Weight-Bearing Rehabilitation Robot. The intervention effects of both groups were compared.

Results

The intervention group demonstrated significant improvements in knee joint function post-surgery compared to the control group. The mean range of motion (ROM) in the experimental group increased from 41.63 ± 5.97° pre-intervention to 55.89 ± 5.13° post-intervention, while the control group's ROM improved from 40.65 ± 3.43° to 49.78 ± 5.27° (t = 5.635, p < 0.001). Similarly, the Health Status Score (HSS) increased from 43.07 ± 3.83 to 59.93 ± 3.30 in the experimental group, while the control group showed an increase from 43.76 ± 4.06 to 54.39 ± 4.39 (t = 6.850, p < 0.001). These findings indicate a more substantial recovery in knee joint functionality in the experimental group, suggesting that robotic-assisted rehabilitation facilitated enhanced functional recovery. Additionally, pain reduction was significantly better in the experimental group. At 24 h post-surgery, the Visual Analog Scale (VAS) pain score for the experimental group was 3.45 ± 0.96, compared to 3.98 ± 0.93 in the control group (t = -2.647, p = 0.010). At 48 h, the VAS score in the experimental group was 2.37 ± 0.49, significantly lower than the control group's 3.09 ± 0.66 (t = -5.923, p < 0.001). By discharge, however, the difference in VAS scores between the two groups was no longer statistically significant (p = 0.096). Furthermore, the intervention group had a significantly shorter hospital stay (7.07 ± 0.83 days) compared to the control group (7.96 ± 1.01 days) (t = -4.630, p < 0.001). No complications, such as secondary fractures or deep vein thrombosis, were reported in either group during hospitalization.

Conclusion

Utilizing the intelligent weight-bearing robot in post-ACL reconstruction rehabilitation significantly improves knee function, reduces discomfort, and shortens hospital stay, highlighting the importance of innovation in medical rehabilitation.

Multi-planar instability, laxity and reduced knee flexion during the support phase of walking are determinants of return to sports

Background: After anterior cruciate ligament reconstruction, some patients are not recommended to return to high-level physical activity because they fail to pass return-to-sports tests. The kinematic difference between these patients and those who pass the return-to-sports tests is unclear.

Methods: Eighty-two patients who received anatomic single-bundle anterior cruciate ligament (ACL) reconstruction for unilateral ACL injury underwent return-to-sport tests during a hospital visit at a minimum of 9 months (9–11 months) of follow-up. Fifteen patients who passed the return-to-sports tests (RTS group) and fifteen patients who did not (NRTS group) were randomly selected to perform a treadmill walk under dual-fluoroscopic imaging system surveillance for a 6 degrees of freedom kinematic evaluation.

Results: Of the 82 patients, 53 passed the return-to-sports tests 9 months after surgery, with a return-to-sports rate of 64.6%. In the stance phase, the NRTS group had a larger anterior tibial translation (1.00 ± 0.03 mm vs. 0.76 ± 0.03 mm, p = 0.001), a larger lateral tibial movement (1.61 ± 0.05 mm vs. 0.77 ± 0.05 mm, p < 0.001), a larger distal tibial displacement (−3.09 ± 0.05 mm vs. −2.69 ± 0.05 mm, p < 0.001), a smaller knee flexion angle (6.72 ± 0.07° vs. 8.34 ± 0.07°, p < 0.001), a larger varus angle (−0.40 ± 0.03°VS. -0.01 ± 0.03°, p < 0.001) and a larger external rotation angle (1.80 ± 0.05° vs. 1.77 ± 0.05°, p < 0.001) than the RTS group. The maximum anterior tibial translation of the NRTS group is also larger than that of the RTS group (3.64 ± 0.42 mm vs. 3.03 ± 0.59 mm, p = 0.003).

Conclusion: Compared with patients passing RTS tests, those who fail to pass show significant anterior, lateral, and rotational instability; knee laxity; and reduced flexion angle of the knee in the support phase during walking, which may be the possible factors hindering a return to sports.