Artikel
Evaluation of Antero-Posterior and Rotatory Instability after ACL Reconstruction: a Comparison of Modified Over-the-top Method and Bone Tunnel Method
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Autoren
Veröffentlicht: | 19. Oktober 2004 |
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Gliederung
Text
Introduction
The purpose of this study is to evaluate antero-posterior (AP) and rotatory instability after ACL reconstruction using the patella tendon and to compare the modified over-the-top method (OT) with the bone tunnel method (BT).
Methods
The OT method or the BT method by inside-out was performed for unilateral ACL injury in 39 patients (OT: 20, BT: 19). Orthopeadic System's knee motion analyzer (CA4000) was used to measure the following items. The total displacement (TD) was measured during the shift from anterior drawing under a weight of 30lbs to posterior drawing under a weight of 20lbs at 20 degrees of flexion. Rotatory instability was sized dynamically by the pivot shift test. This curve was then qualitatively analyzed, and the anterior displacement of the tibia (PS) was measured.
Results
In the OT group, 5 cases showed below -3mm of side-to-side difference in TD. Thirteen cases of the OT group and 9 cases of the BT group showed no instability. In the cases with knee instability, we classified the patients into 3 types: Type A- Cases with both AP and rotatory instability; Type B-Cases with only rotatory instability; and Type C-Cases with only AP instability.
Conclusions
The results of TD suggest that cases in the OT group showed a tendency towards excessive AP stiffness of the knee. Cases with rotatory instability in spite of good AP stability were more common in the BT group. This finding suggests that the difference of the graft position of the femoral side had an influence on rotatory instability.