Article
Internal brace augmentation of the scapholunate interosseous ligament reapir: A biomechanical study
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Authors
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Il Jung Park
- Orthopaedic Biomechanics Laboratory, VA Medical Center, Department of Orthopedic Surgery, The Catholic Univ of Korea, Long Beach, United States
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Mauro Maniglio
- Orthopaedic Biomechanics Laboratory, VA Medical Center, Department of Orthopedics and Traumatology, Inselspital Bern, Long Beach, United States
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Steven S. Shin
- Kerlan Jobe Orthopaedic Clinic, Los Angeles, United States
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In Jun Koh
- Orthopaedic Biomechanics Laboratory, VA Medical Center, Department of Orthopedic Surgery, The Catholic Univ of Korea, Long Beach, United States
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Nilay A. Patel
- Orthopaedic Biomechanics Laboratory, VA Medical Center, Department of Orthopedic Surgery, Univ of California, Irvine, Long Beach, United States
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Charles C. Lin
- Orthopaedic Biomechanics Laboratory, VA Medical Center, Department of Orthopedic Surgery, Univ of California, Irvine, Long Beach, United States
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Victor Truong
- Orthopaedic Biomechanics Laboratory, VA Medical Center, Long Beach, United States
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Michelle H. McGarry
- Orthopaedic Biomechanics Laboratory, VA Medical Center, Long Beach, United States
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Thay Q. Lee
- Orthopaedic Biomechanics Laboratory, VA Medical Center, Department of Orthopedic Surgery, Univ of California, Irvine, Long Beach, United States
| Published: | February 6, 2020 |
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Outline
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Objectives/Interrogation: Acute, complete tears of the scapholunate interosseous ligament (SLIL) are best treated by open reduction and direct repair. However, direct repair of this ligament is often unreliable. It is not easy to repair securely, and therefore requires a long period of pin fixation and postoperative cast immobilization.
Internal bracing (IB) is a new augmentation method using Fiber tape that has been applied to an orthopedic applications. However, there is no published paper about the SLIL injury treated by this augmentation.
This study aimed to compare the biomechanical strength of SLIL repair only and repair augmented with IB.
Methods: Fourteen fresh frozen cadaveric specimens (7 matched pairs) were used in this study. From each matched pair of specimens, one limb was randomly assigned to underwent repair only and the contralateral limb was underwent repair augmented with IB. In the repair only group, dorsal, palmar, and proximal parts of the SLIL were sharply dissected off its scaphoid attachment site and the dorsal part was repaired using 2 single-loaded suture anchors. In the repair with IB augmentation group, the augmentation using Fiber tape (Internal Brace, Arthrex) was performed using SwiveLock suture anchors after the repair.
Each specimen was mounted on the Instron machine. Specimens were preloaded to 3 N and then cyclically loaded in tension from 3 to 25 N for 30 cycles. After cyclic testing, specimens were tested in tension to failure at a rate of 20 mm/min. Load to failure, extension, and stiffness were calculated, and the mode of failure was noted.
Results and Conclusions: In cyclic tensile testing, the pattern of repair with IB augmentation is much similar to the intact dorsal SLIL model than that of repair only. In other words, under the load of 3 to 25 N, IB augmentation made a condition very similar to the intact ligament. In the repair with IB augmentation group, the maximum extension and the hysteresis were significantly lower than in the repair only group in each cycle. In load to failure testing, the repair with IB augmentation group demonstrated a significantly higher the ultimate load (37.7 N vs 98.5 N) and load at clinical failure (4 mm; 33.4 N vs 84.1 N) compared with the repair only group.
The SLIL repair with IB augmentation demonstrated significantly higher strength compared with the repair only. However, additional testing of the orientation, location, and number of IB should be followed to effectively address flexion of the scaphoid.
