Clinical outcome and computer tomography based tunnel placement evaluation following arthroscopic anteromedial portal anterior cruciate ligament reconstruction in non-athletic population.

Abstract

Background: The morphology of distal femur and proximal tibia varies between different ethnicities, and it can affect the tunnel dimensions and positions while doing ACL reconstruction which may affect the clinical outcome. There is limited data on the clinical outcome and CT based tunnel placement evaluation in femur and tibia of Indian nonathletic population.

Methods: Thirty non-athletic patients with mean age of 25.50±6.9 years and ACL rupture who underwent single bundle hamstring autograft arthroscopic ACL reconstruction by anteromedial portal were included in the study. Their preoperative IKDC Score, Lysholm-Tegner score, Tegner activity level were calculated and knee stability was assessed clinically using anterior drawer test, Lachman test and pivot shift test. The CT scan of the operated knee was done once the complete extension of the knee was achieved. Using the multimodality workstation available at the department of radio-diagnosis the tunnel parameters of femoral and tibial tunnel was calculated. After 6 months the patients were reassessed for clinical and radiological outcome. The postoperative outcome was compared with preoperative outcome.

Results: There was a significant difference in preoperative and postoperative score, the difference in IKDC score was 15.08 points, improvement of 14.65 points was seen in Lysholm-Tegner score and there was marked improvement in Tegner activity level. Tests for knee stability were normal in >90% of patients postoperatively. The CT evaluation showed that the femoral tunnels were positioned at 28.45%±3.69% (20.16%-38.35%) along the deep-shallow axis and 25.81%±3.819% (20.69%-37.35%), the mean tunnel obliquity compared to the femoral shaft axis were 47.34°±5.427° (37.68°-58.16°) in the coronal plane and 47.93°±7.023° (35.11°-63.95°), the mean tunnel length was 3.38 cm±0.331 cm (2.79 cm-4.18 cm). The tibial tunnel were positioned at 45.63%±5.832% (32.23%-58.23%) along the anterior-posterior axis and 47.70%±2.26% (42.40%-51.96%) along the medio-lateral axis. The tibial tunnel length was found to be 3.89 cm±0.519 cm (3.05 cm-5.06 cm).

Conclusion: This study helps to ascertain that the ACL reconstruction via anteromedial portal technique using femoral offset zig followed by postoperative home-based rehabilitation technique gives favorable clinical outcomes in Indian non-athletic patients. All patients had improvement in stability of knee after the surgery. The position of femoral tunnels was anatomical but in comparison to Caucasian patients its placement was deeper and higher. Hence, we conclude that the anteromedial portal technique of ACL reconstruction provides favorable clinical outcome and adequate anatomical tunnel placement in Indian non athletic patients.