Computational comparison of different plating strategies in medial open-wedge high tibial osteotomy with lateral hinge fractures

Background Lateral hinge fracture (LHF) is associated with nonunion and plate breakage in high tibial osteotomy (HTO). Mechanical studies investigating fixation strategies for LHFs to restore stability and avoid plate breakage are absent. This study used computer simulation to compare mechanical stabilities in HTO for different LHFs fixed with medial and bilateral locking plates. Methods A finite element knee model was created with HTO and three types of LHF, namely T1, T2, and T3 fractures, based on the Takeuchi classification. Either medial plating or bilateral plating was used to fix the HTO with LHFs. Furthermore, the significance of the locking screw at the combi hole (D-hole) of the medial TomoFix plate was evaluated. Results The osteotomy gap shortening distance increased from 0.53 to 0.76, 0.79, and 0.72 mm after T1, T2, and T3 LHFs, respectively, with medial plating only. Bilateral plating could efficiently restore stability and maintain the osteotomy gap. Furthermore, using the D-hole screw reduced the peak stress on the medial plate by 28.7% (from 495 to 353 MPa), 26.6% (from 470 to 345 MPa), and 32.6% (from 454 to 306 MPa) in T1, T2, and T3 LHFs, respectively. Conclusion Bilateral plating is a recommended strategy to restore HTO stability in LHFs. Furthermore, using a D-hole locking screw is strongly recommended to reduce the stress on the medial plate for lowering plate breakage risk.

Will the Strength of the Clavicle Plate be Increased by Inserting Small Screws into the Empty Holes above the Fracture Site?

Background: Open reduction and plate fixation is the standard surgery for displaced midshaft clavicle fractures because of biomechanical stability. Implant failure like plate breakage or deformation is the most serious complication of plate fixation. Several plate designs for midshaft clavicle fractures have been introduced, but traditional superior plate has been mostly used.Methods: We generated the clavicle 3D image using the computed tomography (CT) of the left normal clavicle of a 54-year-old female, and then made the comminuted midshaft clavicle fracture model with 10-mm fracture site gap. The fracture model was fixed with 7-hole superior locking compression plate. Finite element analysis (FEA) was performed between the presence (model B) and absence (model A) of screws above the fracture site.Results: The average peak stress from the cantilever bending force was much greater than the peak stress from the axial compression and axial torsion force. This means that the cantilever loading force is the main force which could cause plate breakage or deformation. The maximal stress of the model B was lower than the one of the model A. Therefore, model B showed superior biomechanical property than model A under all loading conditions, especially cantilever bending force.Conclusions: The peak stress of the superior clavicle plate could be decreased just by inserting a small screw into the screw hole above the fracture site.

Biomechanical Characterization of Failure the 316L Stainless Steel for Femoral Compression Plates

The aim of this paper is to examine a premature breakage of two compression plates for fixing broken bones with different patients for the period of their recovery. Each compression plate's breakage can induce grave consequences such as a new surgery, unexpected undesired complications and a prolonged healing time. The investigation of the compression plate breakage causes required an examination of the chemical composition and steel hardness, metallographic examination as well as that of the compression plate breakage surface by means of macroscopic and microscopic observations using microscope. On the origin of the results it can be established that the breakage was caused by high static load.

Volar Locking Plate Breakage after Nonunion of a Distal Radius Osteotomy

We report a 38-year-old male with a nonunion followed by plate breakage after volar plating of a distal radius osteotomy. Volar locking plates have added a new approach to the treatment of distal radius malunions, due to a lower morbidity of the surgical approach and the strength of the final construction, allowing early mobilization and return to function. Conclusion. Plate breakage is an uncommon complication of volar locking plate fixation. To our knowledge, few cases have been described after a distal radius fracture and no case has been described after a distal radius corrective osteotomy. In the present case, plate breakage appears to have occurred as a result of a combination of multiple factors as the large corrective lengthening osteotomy, the use of demineralized bone matrix instead of bone graft, and the inappropriate fixation technique as an unfilled screw on the osteotomy site, rather than the choice of plate.

Feline pantarsal arthrodesis using pre-contoured dorsal plates applied according to the principles of percutaneous plate arthrodesis

SummaryObjective: To describe the surgical technique for pantarsal arthrodesis (PTA) in cats according to the principles of percutaneous plate arthrodesis with application of a pre-contoured dorsal plate, without external coaptation and to report the long-term clinical outcome.Materials and methods: Retrospective review was performed of all cats treated by percutaneous plate application using a new pre-contoured dorsal plate for PTA between 2008 and 2011. Inclusion criteria were clinical and radiographic records plus clinical follow-up to at least six weeks. Data recorded included signalment, indication for surgery, postoperative care, and complications encountered. Radiographs were assessed for arthrodesis progression and complications. Outcome was assessed using an owner questionnaire.Results: Eleven cats were treated for tarsal injuries and met the inclusion criteria. Mean age was 86 ± 45 months, weight 4.50 ± 0.92 kg. The only major short-term complication encountered was wound dehiscence requiring sedation and re-suturing. In the medium-term (23.3 months ± 11.6 months) eight out of nine cats returned to normal activity and one cat showed intermittent lameness. Long-term (34.3 months ±17.5 months) radiographic evaluation was performed in seven out of nine cats; six manifested complete arthrodesis and one sustained plate breakage. Based on owner questionnaire, all nine cats returned to normal activity in the long-term, even the case with plate breakage.Conclusion: Based on our results, PTA using a custom pre-contoured dorsal plate is a suitable salvage surgery for treatment of severe tarsal injuries in cats.