Journal of Musculoskeletal Trauma

Biomechanical Analysis of Hybrid External Fixation for the Distal Tibial Fractures: A FEM Study: Duk Young Jung, Boug Ju Kim, Seok Bae Ryu, Jong Keon Oh; J Korean Fract Soc 2004;17(2):160-166. Published online April 30, 2004; DOI: https://doi.org/10.12671/jkfs.2004.17.2.160

Abstract PDF: PURPOSE
To analyze the biomechanical effects of different frame configurations of the hybrid external fixators for distal tibial fractures on the frame stiffness and stress distribution with a finite element method (FEM).
MATERIALS AND METHODS
Five configurations were simulated: Group I: two wires with convergence angle of 60degrees, Group II: 3rd wire on a bisector axis of the group I. Group III: two wires with 30degrees. Group IV: 3rd wire on a bisector axis. Group V: two wires with 30degree and a half pin on the distal articular fragment. Each group was simulated under compression, torsion, anterior-posterior and lateral-medial bending load. Stiffness, stress and deformation values were calculated.
RESULTS
The overall stiffness was increased by 15~30% with the addition of a third wire, and by 150~400% with a anteromedial half pin on the articular fragment. The half pin decreased the stress level of the frame by about 43% and the deformation of the 5/8 ring by about 30%.
CONCLUSION
The addition of a half pin on the articular fragment is not only a method of increasing the stiffness but also a way of decreasing the stress concentration and the deformation of the frame.

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Hybrid External Fixation and Limited Internal Fixation for Severe Open Tibial Shaft Fractures: Hong Jun Han, Soo Uk Chae, Ul Oh Jeung; J Korean Soc Fract 2003;16(1):52-58. Published online January 31, 2003; DOI: https://doi.org/10.12671/jksf.2003.16.1.52

Abstract PDF: PURPOSE
To evaluate the radiographic and clinical results of severe open tibial shaft fracture treated by hybrid external fixation and limited internal fixation.
MATERIALS AND METHODS
We reviewed 25 patients open tibial shaft fracture(> or =Gustillo classification type II) which were treated with hybrid external fixation(AnyFixR) that was invented by authors and limited internal fixation between June 1998 to June 2001. 20 males and 5 females were minimum follow up period of 12 months(12-27 months). The mean age was 45 old years(11-72 old years). The results were based on the assessment radiographical analysis with duration of bony union, delayed union including of states of nonunion and malunion, clinical analysis with pain, joint range of motion, wound infection and skin & soft tissue coverage. All fractures were classified according to the Gustilo classification, there were 6 cases of type II, 9 cases of type IIIa and 10 cases of type IIIb. The cause of injury, there were 18 cases of motor vehicle accident, 5 cases of direct trauma and 2 cases of fall from height.
RESULTS
In twenty-five cases, fifteen had union, the average time of bone union was 6.8 months and additional bone graft without change of external fixator performed in ten cases, but one case have failed and then change of intramedullary nail with bone graft. In the group of bone graft, bone union was completed at mean 8.7 months. According to the clinical analysis, no pain in the fracture site, in complications, there were 2 cases of mild joint range of motion that has acceptable result and 2 cases of wound infection were treated with effective antibiotics theraphy and wound dressing. Five cases need to coverage of the open wound, 3 cases were flap operation and each case were muscle transfer, skin graft without change of external fixator.
CONCLUSION
The use of hybrid external fixation and limited internal fixation in severe open tibial shaft fracture to be successful for the stabilization of fracture and subsequent plastic and/or orthopaedic procedure for muscle and skin coverage, bone grafting are more easily accomplished without change of external fixator.

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The Biomechanics of Hybrid External Fixator: The Effect of Periarticular Half Pin on Frame Stiffness: Jong Keon Oh, Duk Young Jung, In Su Kim; J Korean Soc Fract 2002;15(2):114-122. Published online April 30, 2002; DOI: https://doi.org/10.12671/jksf.2002.15.2.114

Abstract PDF: OBJECTIVES
The purpose of this study was to identify the biomechanical effect of periarticular half pin in the hybrid external fixator.
METHODS
Simulated tibial plateau fractures were created using a polyvinylchloride pipe. Seven frame configurations were tested : a four-ring Ilizarov frame, a hybrid frame with three wires on peri-articular fragment, hybrid frames with wires and half pins on peri-articular fragment by four different configurations, a hybrid frame constructed with multiple levels of fixation in the periarticular fragment. A materials testing machine was used to apply pure compression, anterior and posterior bending, medial and lateral bending, and torsion. Stiffness values were calculated from the load deformation and torque angle curves RESULTS: The overall stiffness of the hybrid frame was increased up to 30% by replacing a coronal tension wire with a half pin placed on the sagittal plane. The hybrid frame constructed with two wires and a half pin on the sagittal plane of the periarticular fragment showed overall stiffness compatible with that of multi-level peri-articular fixation frame.
CONCLUSION
Our results show that the half pin placed on the periarticular fragment can be a effective tool to increase the stiffness of hybrid external fixators in this periarticular tibia fracture model.

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The Biomechanics of Hybrid External Fixator: Effectiveness of Bar to Ring Connection: Jong Keon Oh, Duk Young Jung, Seong Yong Yoon; J Korean Soc Fract 2001;14(4):783-791. Published online October 31, 2001; DOI: https://doi.org/10.12671/jksf.2001.14.4.783

Abstract PDF: OBJECTIVES
The biomechanical effects of bar to ring connection in a hybrid external fixator have not yet been clearly identified. The purpose of this study was to identify the biomechanical effects of bar to ring augmentation in the hybrid external fixator.
METHODS
Simulated tibial plateau fractures were created using a polyvinylchloride pipe. Groups of simulated periarticular tibia fractures were stabilized with one of six different external fixation constructs with components from one manufacturer. Six frame configurations were tested: a four-ring Ilizarov frame, a hybrid frame without bar to ring augmentation, hybrid frames with three different bar to ring augmentations, a hybrid frame constructed with multiple levels of fixation in the periarticular fragment. A material testing machine was used to apply pure compression, anterior and posterior bending, medial and lateral bending, and torsion. Stiffness values were calculated from the load deformation and torque angle curves RESULTS: The four-ring Ilizarov fixator was the stiffest in all modes of testing. Frame augmentation with three different types of bar-to-ring connection did increase stiffness in all modes of testing. No statistical difference was found between the stiffness of the frames with three different types of bar to ring augmentations. The stiffness of a hybrid frame constructed with multiple levels of fixation in the periarticular fragment was comparable to that of the fixators with bar to ring augmentation.
CONCLUSION
Our results show that the bar to ring augmentation increases the overall stiffness of hybrid external fixators in this periarticular tibia fracture model by 27-76%.

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TREATMENT OF PROXIMAL TIBIA FRACTURE WITH HYBRID EXTERNAL FIXATOR: Tae Woo Park, Sung Do Cho, Youg Sun Cho, Bum Soo Kim, Sogu Lew, Su Yeon Hwang; J Korean Soc Fract 2001;14(2):285-290. Published online April 30, 2001; DOI: https://doi.org/10.12671/jksf.2001.14.2.285

Abstract PDF

PURPOSE
To evaluate the results and usefulness of hybrid external fixator in the treatment of proximal tibia fracture. MATERIAL AND METHOD: From Jan. 1997 to Jan. 2000, 19 proximal tibia fracture were treated with hybrid external fixator with or without limited internal fixation to stabilize the articular surface. All fractures were classified according to the AO classification. The results were analyzed by ROM(range of motion), bony union time, fracture reduction with MPTA(medial proximal tibial angle) and joint congruency.
RESULT
There were 1 A2, 7 A3, 1 C1, 8 C2, 2 C3 proximal tibial fractures according to the AO classification. Open fractures were 10 patients. The mean bony union time was 13 wks(range 8-36wks) and the mean length of time in the external fixator was 14wks(range 8-36wks). At last follow up, the MPTA of the proximal tibia was 87.9 degree. 2 patients developed varus(82 degree) and valgus(92 degree) deformity respectively. Complications were intermittent pin drainage in 6 patients(31.6%), deep infection in 1 patient(5.3%) and nonunion in 4 patients(21%) required bone graft and internal fixation with plate at 6 months postoperatively. Four nonunions were 3 C2 and 1 C3 according to the AO classification and three were open fracture(1 type I, 1 type IIIb, 1 type IIIc : Gustilo type) CONCLUSION: Hybrid external fixation is a good treatment option for proximal tibial fractures. However, nonunion and angular deformity would occur in severe metaphyseal comminution and soft tissue injury. Accurate fracture reduction and careful soft tissue management is prerequisite and if necessory early bone graft should be considered in such cases.

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Staged Management of High Energy Proximal Tibia Fractures with Severe Soft Tissue Damage
Seung-Ryul Lee, Jae-Hoon Yang, June-Kyu Lee, Hyun-Dae Shin, Kyung-Cheon Kim, Kyu-Woong Yeon, Young-Mo Kim
Journal of the Korean Fracture Society.2009; 22(3): 152. CrossRef

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Hybrid External Fixation for Periarticular or Segmental Fractures of Tibia: Hong Jun Han, Yeung Jin Kim, Jae Myoung Kim; J Korean Soc Fract 2001;14(1):44-51. Published online January 31, 2001; DOI: https://doi.org/10.12671/jksf.2001.14.1.44

Abstract PDF: PURPOSE
To analyze the clinical outcomes of the hybrid external fixation which is more comfortable and simply appliable than Ilizarov fixator MATERIAL AND METHOD: 28-patients of periarticular or segmental tibia fracture from may 1998 to october 1999 were treated with hybrid external fixator (AnyFixÂ®)that was invented by authors. It consists of two rings at epiphysis(full or 2/3 ring), 3 or 4 rods connecting 2 rings, K-wires, half pins, and specially designed push pins and crane pins which can be used as a reduction device and fixation pins. And it was used as a definitive modality. Joint exercise was started immediately after operation and partial weight bearing was permitted 4 weeks after initial application.
RESULT
The average time of bone union was 4.7 months, articular step-off of all cases were less than 1 mm. As a complication, there was no limitation of range of motion except one case of 10Â° dorsiflexion limitation of the ankle, and 1 case of deep wound infection. Clinical assesments of knee and ankle joint showed 14 cases of excellent, 9 cases of good, 3 cases of fair in total 26 cases of proximal or distal tibia fracture except 2 infected non-union.
CONCLUSION
Hybrid external fixation is effective method for periarticular or segmental tibia fracture and it gives simple applicability, firm stability and much less discomfort.

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