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Articles by J. K Seon
Total Records ( 4 ) for J. K Seon
  J. K Seon , S. J Park , K. B Lee , H. R Gadikota , M Kozanek , L. S Oh , S Hariri and E. K. Song
  Background

Screw and suture fixations are the most commonly used methods of fixation in treatment of anterior cruciate ligament tibial avulsion fractures. Even though a few biomechanical studies have compared the stability of the 2 fixation techniques, a clinical comparison has not yet been reported.

Hypothesis

The authors hypothesized that both fixations would be identical in all studied clinical outcome measures at a minimum 2-year follow-up.

Study Design

Cohort study; Level of evidence, 3.

Materials and Methods

Thirty-three patients treated with either screw fixation (16 patients) or suture fixation (17 patients) within 1 month of the anterior cruciate ligament tibial avulsion fracture (type II or III) without associated ligamentous injury were included. All patients were evaluated at a minimum 2-year follow-up in terms of Lysholm knee scores and return to preinjury activities. Knee stability was compared based on the Lachman test and stress radiography.

Results

No significant differences were found between the 2 groups in terms of average Lysholm knee scores (91.7 in the screw group and 92.7 in the suture group, P = .413) at follow-up. All patients except 2 (1 in each group) returned to preinjury activity levels. However, flexion contractures (5° to 10°) were found in 3 patients in the screw group and 2 patients in the suture group without significant intergroup difference. Stabilities based on the Lachman test and instrumented stress radiography were also similar between the 2 groups at follow-up. However, 2 patients in the screw group and 1 in the suture group showed more than 5 mm laxity compared with the contralateral knee on stress radiographs.

Conclusion

Both the screw and suture fixation techniques for the anterior cruciate ligament tibial avulsion fracture produced relatively good results in terms of functional outcomes and stability without any significant differences. However, some patients in both groups showed residual laxity or flexion contractures.

  J. L Wu , J. K Seon , H. R Gadikota , A Hosseini , K. M Sutton , T. J Gill and G. Li
  Background

The in situ forces of the anteromedial (AM) and posterolateral bundles (PL) of the anterior cruciate ligament (ACL) under simulated functional loads such as simulated muscle loads have not been reported. These data are instrumental for improvement of the anatomical double-bundle ACL reconstruction.

Hypothesis

The load-sharing patterns of the 2 bundles are complementary under simulated muscle loads.

Study Design

Descriptive laboratory study.

Methods

Eight cadaveric knees in this study were sequentially studied using a robotic testing system. Each knee was tested under 3 external loading conditions including (1) a 134-N anterior tibial load; (2) combined rotational loads of 10 N·m of valgus and 5 N·m internal tibial torques; and (3) a 400-N quadriceps muscle load with the knee at 0°, 15°, 30°, 60°, and 90° of flexion. The in situ forces of the 2 bundles of ACL were determined using the principle of superposition.

Results

Under the anterior tibial load, the PL bundle carried peak loads at full extension and concurrently had significantly lower force than the AM bundle throughout the range of flexion (P <.05). Under the combined rotational loads, the PL bundle contributed to carrying the load between 0° and 30°, although less than the AM bundle. Under simulated muscle loads, both bundles carried loads between 0° and 30°. There was no significant difference between the 2 bundle forces at all flexion angles (P > .05).

Conclusion

Under externally applied loads, in general, the AM bundle carried a greater portion of the load at all flexion angles, whereas the PL bundle only shared the load at low flexion angles. The bundles functioned in a complementary rather than a reciprocal manner to each other.

Clinical Relevance

The data appear to support the concept that both bundles function in a complementary manner. Thus, how to re-create the 2 bundle functions in an ACL reconstruction should be further investigated.

  H. R Gadikota , J. L Wu , J. K Seon , K Sutton , T. J Gill and G. Li
  Background

Anatomical reconstruction techniques that can restore normal joint kinematics without increasing surgical complications could potentially improve clinical outcomes and help manage anterior cruciate ligament injuries more efficiently.

Hypothesis

Single-tunnel double-bundle anterior cruciate ligament reconstruction with anatomical placement of hamstring tendon graft can more closely restore normal knee anterior-posterior, medial-lateral, and internal-external kinematics than can conventional single-bundle anterior cruciate ligament reconstruction.

Study Design

Controlled laboratory study.

Methods

Kinematic responses after single-bundle anterior cruciate ligament reconstruction and single-tunnel double-bundle anterior cruciate ligament reconstruction with anatomical placement of hamstring tendon graft were compared with the intact knee in 9 fresh-frozen human cadaveric knee specimens using a robotic testing system. Kinematics of each knee were determined under an anterior tibial load (134 N), a simulated quadriceps load (400 N), and combined torques (10 N·m valgus and 5 N·m internal tibial torques) at 0°, 15°, 30°, 60°, and 90° of flexion.

Results

Anterior tibial translations were more closely restored to the intact knee level after single-tunnel double-bundle reconstruction with anatomical placement of hamstring tendon graft than with a single-bundle reconstruction under the 3 external loading conditions. Under simulated quadriceps load, the mean internal tibial rotations after both reconstructions were lower than that of the anterior cruciate ligament–intact knee with no significant differences between these 3 knee conditions at 0° and 30° of flexion (P > .05). The increased medial tibial shifts of the anterior cruciate ligament–deficient knees were restored to the intact level by both reconstruction techniques under the 3 external loading conditions.

Conclusion

Single-tunnel double-bundle anterior cruciate ligament reconstruction with anatomical placement of hamstring tendon graft can better restore the anterior knee stability compared with a conventional single-bundle reconstruction. Both reconstruction techniques are efficient in restoring the normal medial-lateral stability but overcorrect the internal tibial rotations.

Clinical Relevance

Single-tunnel double-bundle anterior cruciate ligament reconstruction with anatomical placement of hamstring tendon graft could provide improved clinical outcomes over a conventional single-bundle reconstruction.

  J. K Seon , H. R Gadikota , J. L Wu , K Sutton , T. J Gill and G. Li
 

Background: Anterior cruciate ligament (ACL) deficiency alters 6 degrees of freedom knee kinematics, yet only anterior translation and internal rotation have been the primary measures in previous studies.

Purpose: To compare the 6 degrees of freedom knee kinematics and the graft forces after single- and double-bundle ACL reconstructions under various external loading conditions.

Study Design: Controlled laboratory study.

Methods: Ten human cadaveric knees were tested with a robotic testing system under 4 conditions: intact, ACL deficient, single-bundle reconstructed with a quadrupled hamstring tendon graft, and double-bundle reconstructed with 2 looped hamstring tendon grafts. Knee kinematics and forces of the ACL or ACL graft in each knee were measured under 3 loading conditions: an anterior tibial load of 134 N, a simulated quadriceps muscle load of 400 N, and combined tibial torques (10 N·m valgus and 5 N·m internal tibial torques) at 0°, 15°, 30°, 60°, and 90° of knee flexion.

Results: The double-bundle reconstruction restored the anterior and medial laxities closer to the intact knee than the single-bundle reconstruction. However, the internal rotation of the tibia under the simulated quadriceps muscle load was significantly decreased when compared with the intact knee after both reconstructions, more so after double-bundle reconstruction (P < .05). The entire graft force of the double-bundle reconstruction was more similar to that of the intact ACL than that of the single-bundle reconstruction. However, the posterolateral bundle graft in the double-bundle reconstructed knee was overloaded as compared with the intact posterolateral bundle.

Conclusion: The double-bundle reconstruction can better restore the normal anterior-posterior and medial-lateral laxities than the single-bundle reconstruction can, but an overloading of the posterolateral bundle graft can occur in a double-bundle reconstructed knee.

Clinical relevance: Both single-bundle and double-bundle techniques cannot restore the rotational laxities and the ACL force distributions of the intact knee.

 
 
 
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