UCSF

Background

Multiple techniques are used for femoral tunnel drilling in ACL reconstruction, including the Mini-two Incision Method (MT) and Anteromedial Portal Technique (AM). Both techniques allow for independent placement of the femoral tunnel, though there are no reports comparing kinematics and cartilage health after these reconstructions. We hypothesized that both techniques would result in the restoration of normal knee kinematics and show no evidence of early cartilage degeneration.

Methods

A total of 20 patients were evaluated one year after ACL reconstruction, including 10 patients after MT and 10 patients after AM. MR-imaging was acquired bilaterally with the knee loaded in extension and flexion to evaluate the kinematics of the reconstructed knee compared with the normal knee. Quantitative cartilage imaging was obtained and compared with 10 matched control subjects. The Marx Activity Rating Scale and KOOS survey were administered.

Results

The tibia was positioned significantly more anteriorly in extension and flexion relative to the contralateral knee for the MT group. The tibial position in the AM group was not significantly different from the patient's contralateral knee. T1ρ values in the central-medial tibia were significantly elevated in the MT group compared with the Control group. KOOS Symptom scores were significantly better for the MT group compared with the AM group.

Conclusions

We have observed in vivo differences in knee kinematics and early cartilage degeneration between patients following MT and AM ACL reconstructions. Both techniques allow for anatomic ACL reconstruction, though the MT group shows significant early differences compared with the patient's normal knee.