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Evaluation of firm fracture fixation of distal femoral locking compression plate and condylar buttress plate. Subjects and methods: Experimental, descriptive, cross-sectional and comparative study of firm fracture fixation of distal femoral locking compression plate and buttress condylar plate in treatment of femoral supracondylar fracture (type A2) and femoral intercondylar fracture (type C2).
Journal of military pharmaco-medicine no8-2019 STUDYING FIRM FRACTURE FIXATION OF DISTAL FEMORAL LOCKING COMPRESSION PLATE AND BUTTRESS CONDYLAR PLATE ON THE SAMPLE OF LABORATORY FRACTURE FIXATION Hoang Ngoc Minh1; Pham Dang Ninh2; Nguyen Quang Trung3 SUMMARY Objectives: Evaluation of firm fracture fixation of distal femoral locking compression plate and condylar buttress plate Subjects and methods: Experimental, descriptive, cross-sectional and comparative study of firm fracture fixation of distal femoral locking compression plate and buttress condylar plate in treatment of femoral supracondylar fracture (type A2) and femoral intercondylar fracture (type C2) Results: The linkage breakdown force on the sample of laboratory fracture fixation of distal femoral locking compression plate: Compression KA-N: 4,010.37 ± 509.50 N and KC-N: 4,620.27 ± 315.85 N; bending KA-U: 704.33 ± 110.45 N and KC-U: 699.26 ± 125.60 N; torsion KA-X: 990.79 ± 166.54 N and KC-X: 1,071.00 ± 222.38 N was higher than that on the sample of laboratory fracture fixation of buttress condylar plate: Compression LA-N: 3,200.04 ± 243.62 N and LC-N: 4,139.28 ± 766.53 N; bending LA-U: 505.76 ± 62.83 N and LC-U: 476.05 ± 59.18 N; torsion LA-X: 888.84 ± 89.02 N and LC-X: 986.26 ± 116.33 N Conclusion: Load force on the sample of laboratory fracture fixation of distal femoral locking compression plate is stronger than load force on the sample of laboratory fracture fixation of buttress condylar plate * Keywords: Distal femoral fracture; Distal femoral locking compression plate; Buttress condylar plate; Experimental bone fixation INTRODUCTION Distal femur fracture in adults consists of supracondylar, intercondylar, medial condyl, lateral condyle fractures, accounting for about - 7% of all types of femur fractures, of which, 70% are supracondylar and intercondylar fractures [7] Distal femur fracture is difficult to treat, leaving many sequelae due to high energy trauma that causes complex fractures, multiple combined lesions, or low-energy injuries seen in the elderly as a result of osteoporosis [6] Sontay General Hospital 103 Military Hospital Vietnam Military Medical University Corresponding author: Hoang Ngoc Minh (drhoangngocminh@gmail.com) Date received: 02/07/2019 Date accepted: 09/10/2019 185 Journal of military pharmaco-medicine no8-2019 Indications for surgery for adult distal femur fractures and bone combination are agreed by the authors in the world and in the country There are many methods and facilities studied for fixation of distal femur fractures such as screw plate, 950 angle plate, DCS (Dynamic Condylar Screw) plate, dual screw plate, condylar buttress plate, locking plate, interlocking nail Each of them has its own advantages and disadvantages that have been reported in conferences [1, 2, 4] At present, surgery for bone combination with condylar buttress plate and locking plate to treat complex distal femur fractures is the first choice as it limits the disadvantages of other types of bone combination facilities [3, 5] However, some reports indicate that there is a failure rate, regardless of condylar buttress plate or locking plate, such as limited knee stretching, prosthetic joint, slow bone healing or displacement of bone To understand the cause of failure, we should pay attention to the postoperative firmness of these two plates That’s why we conduct the topic “Evaluation of firm fracture fixation of distal femur locking compression plate and condylar buttress plate on the sample of laboratory fracture fixation” to grasp the fracture fixation of plates and suggest reasonable postoperative practice programs, preventing complications from limited movement and splinting, screwing off during practice 186 MATERIALS AND METHODS Materials - Sets of 7-hole distal femur locking compression plates (LCP), hard bone lock screws and porous bone lock screws accompanied with sufficient quantity Intercus locking plate type, Germany pure titanium material, screws made from TiAl6V4 compound, ensuring compatibility, without auto-immune effect of the body 204 mm in length, 5.5 mm in thickness, 39.3 mm in width, 17.5 mm in width, 20.0 mm of body holes, screw types 6.5 and 5.0 mm This locking plate has good stiffness and elasticity, high biological similarity, it is designed to be suitable for distal femur anatomy The screw design is quite rigid, durable, resilient body, hard bone screws have a short pitch with a moderate depth, suitable for hard bone structure, porous bone screws have a wide and deep pitch to increase the fixing ability into porous bone, consistent with porous bone structure - Sets of 7-hole condylar buttress plate, hard bone screws and spongy bone screws accompanied with sufficient quantity - 72 fresh beef femurs are captured X-ray in an inclined straight posture to detect and eliminate bone diseases Bones are stored in 2-layer plastic bags at a temperature of -200C Before the test, leave the bone at room temperature Methods * Design of research samples: The bone combination process of distal femoral LCP and condylar buttress plate into the beef femur is done like the bone combination on clinically Journal of military pharmaco-medicine no8-2019 - Sample of plate - bone with fracture line simulating a supracondylar fracture of beef femur (type A2 fracture by AO classification): + Sample KA: Locking plate system supracondylar fracture bone (type A2): 18 samples + Sample LA: Condylar buttress plate system - supracondylar fracture bone (type A2): 18 samples Picture 2: Testing sample of condylar - Sample of plate - bone with fracture line simulating an intercondylar fracture of beef femur (type C2 by AO classification): * Location and testing machine: + Sample KC: Locking plate system intercondylar fracture bone (type C2): 18 samples + Sample LC: Locking plate system intercondylar fracture bone (type C2): 18 samples - Force test sample: + Compression force test sample: 24 samples (KA-N: 6; LA-N: 6; KC-N: 6; LC-N: 6) + Bending force test sample: 24 samples (KA-U: 6; LA-U: 6; KC-U: 6; LC-U: 6) + Torsion test sample: 24 samples (KA-X: 6; LA-X: 6; KC-X: 6; LC-X: 6) buttress plate - Location: At the Material Strengthening Laboratory, Department of Materials and Structural Mechanics, Hanoi University of Science and Technology - Testing machine: MTS Alliance RF/300 with operating principle: The machine’s encoder will measure the compressive, horizontal bending and torsional forces acting on the test sample as well as measure the corresponding deformation of the test sample under the impact forces Compression, horizontal bending and torsional indicators and deformation are continuously measured and transmitted to the computer The computer will automatically build up the graph of force, the deformation of the test specimen within the force limit From the graph, it is possible to calculate the strength of the sample Picture 1: Testing sample of distal femoral LCP Test conditions: Temperature at 250C; air humidity 70% RH 187 Journal of military pharmaco-medicine no8-2019 - Conducting research: + Compressive test: Axial compression of model of bone combination of types of fractures - bone with samples of supracondylar femoral fracture (KA-N, LA-N) and intercondylar femoral fracture (KC-N, LC-N) Picture 3: Measuring machine of compression indicator of distal femoral LCP + Bending test: Done with 3-point horizontal bending conditions, the distance of 02 bearings is 200 mm, bending position is mm The system of bone plates is fixed horizontally, the machine will create horizontal lateral bending forces with supracondylar (KA-U, LA-U) and intercondylar (KC-U, LC-U) bone cut samples + Torsion test: Done with 3-point torsion conditions, the distance of 02 bearings is 200 mm, bending position is mm The system of bone plates is fixed horizontally, the machine will create torsional forces with the 900 axis with supracondylar (KA-X, LA-X) and intercondylar (KC-X, LC-X) bone cut samples Picture 4: Measuring machine of compression indicator of condylar buttress plate * Methods: - Method of experimental, descriptive, comparative research - Research content: Study on firm fracture fixation of the distal femoral LCP and the condylar buttress plate - bone 188 Tests are designed based on the test model of Dirk Wähner, assessing durability of the bone combination means [8, 9], our research model evaluates firm fracture fixation and has a few adaptations suitable to the conditions of experiment in Vietnam * Method of evaluating results: Plotting graphs and calculating forces by statistical algorithm of Hanoi University of Science and Technology Journal of military pharmaco-medicine no8-2019 RESULTS Table 1: Compression force on plate systems - bones with supracondylar and intercondylar fractures (n = 24) Compression force (N) Plate system - supracondylar (A2) and intercondylar (C2) fracture bones Type A2 KA-N (Sd) (n = 6) LA-N (Sd) (n = 6) 0.5 mm 1,329.90 (± 355.90) 1,121.19 (± 230.17) 1.0 mm 1,719.48 (± 384.83) 1.5 mm Type C2 KC-N (Sd) (n = 6) LC-N (Sd) (n = 6) > 0.05 1,194.51 (± 210.07) 953.97 (± 287,56) > 0.05 1,552.09 (± 256.04) > 0.05 2,030.63 (± 241.84) 1,597.88 (± 527.67) > 0.05 2,456.16 (± 641.66) 2,074.99 (± 263.24) > 0.05 3,140.14 (± 288.16) 2,738.34 (± 703.88) > 0.05 2.0 mm 3,225.50 (± 427.18) 2,865.01 (± 548.70) > 0.05 3,915.8 (± 295.43) 3,498.13 (± 787.61) > 0.05 2.5 mm 4,010.37 (± 509.50) 3,200.04 (± 243.62) < 0.05 4,620.27 (± 315.85) 4,139.28 (± 766.53) > 0.05 Fracture movement p p The increment of compression force acting on the models of plates - bones on the two bone fractures of A2 and C2 had no difference in force causing the displacement of a fracture from 0.5 - 2.0 mm with p > 0.05 But when displacing fracture to 2.5 mm, the type A2 fracture had a significant change and difference of force acting on the distal femoral locking compression plate (KA-N): 4,010.37 ± 509.50 N and the condylar buttress plate - bone (LA-N): 3,200.04 ± 243.62 N with p < 0.05 As for C2 sample, the force acting on the distal femoral locking compression plate - bone (KC-N): 4,620.27 ± 315.85 N and the condylar buttress plate - bone (LC-N): 4,139.28 ± 766.53 N, the difference was not statistically significant with p > 0.05 Table 2: Bending force on plate systems - fracture bones (type A2 and C2) (n = 24) Bending force (N) Plate system - supracondylar (A2) and intercondylar (C2) fracture bones Type A2 KA-U (Sd) (n = 6) LA-U (Sd) (n = 6) mm 204.94 (± 70.34) 155.86 (± 48.13) mm 396.37 (± 117.52) mm mm Fracture movement Type C2 KC-U (Sd) (n = 6) LC-U (Sd) (n = 6) > 0.05 139.43 (± 39.09) 105.3 (± 35.22) > 0.05 314.52 (± 88.88) > 0.05 271.34 (± 124.77) 216.28 (± 97.57) > 0.05 537.79 (± 121.16) 499.78 (± 85.32) > 0.05 447.57 (± 107.14) 416.75 (± 134.66) > 0.05 704.33 (± 110.45) 505.76 (± 62.83) < 0.05 699.26 (± 125.60) 476.05 (± 59.18) < 0.05 p p 189 Journal of military pharmaco-medicine no8-2019 The increment of bending force displaced plates - bone from - mm on type A2 and type C2 femoral fractures that had a statistically insignificant difference with p > 0.05 The greater the distortion, the further the difference force increment At mm level, there was a link breakdown, the horizontal bending force exerted on the distal femoral locking plate system - bone (KA-U): 704.33 ± 110.45 N was higher than that of condylar buttress plate - bone (LA-U): 505.76 ± 62.83 N and the force exerted on C2 sample, distal femoral locking plate - bone (KC-U): 699.26 ± 125.60 N was also higher than that of condylar buttress plate - bone (LC-U): 476.05 ± 59.18 N The difference was statistically significant with p < 0.05 Table 3: Torsion force on plate systems - fracture bones (type A2 and C2) (n = 24) Torsion force (N) Plate system - supracondylar (A2) and intercondylar (C2) fracture bones Type A2 Fracture movement Type C2 KA-X (Sd) (n = 6) LA-X (Sd) (n = 6) 421.64 (± 54.73) 390.70 (± 81.15) mm 589.57 (± 88.51) mm mm mm KC-X (Sd) (n = 6) LC-X (Sd) (n = 6) > 0.05 514.21 (± 135.30) 489.13 (± 81.64) > 0.05 533.90 (± 95.10) > 0.05 707.42 (± 213.60) 664.43 (± 98.04) > 0.05 777.02 (± 134.66) 686.91 (± 80.48) > 0.05 829.03 (± 162.50) 826.02 (± 112.04) > 0.05 990.79 (± 166.54) 888.84 (± 89.02) < 0.05 1,071.00 986.26 (± 116.33) < 0.05 p (± 222.38) p The increment of twisting force acting on the two systems of plate - bone also had a change when it started with a - mm shift A type A2 fracture acting on the distal femoral locking compression plate - bone (KA-X): 990.79 ± 166.54 N and condylar buttress plate (LA-X): 888.84 ± 89.02 N with displacement to mm began to have a link breakage, the difference was not statistically significant with p > 0.05 With type C2 fracture, the force acting on the distal femoral locking compression plate - bone (KC-X): 1,071.00 ± 222.38 N and the condylar buttress plate (LC-X): 986.26 ± 116.33 N with a fracture displacement to mm began to have a link breakage, the difference was not statistically significant with p > 0.05 DISCUSSION The femur is the longest bone and the body’s main bearing bone, in which the distal femur has a diverse, complex anatomical structure, an unmatched mechanical and anatomical axis In daily 190 movement activities, the distal femur is subject to the main forces of compression along the axes, bending force, torsion force or a combination of these forces Therefore, the facilities used to combine bones for distal femoral fractures must be Journal of military pharmaco-medicine no8-2019 sufficiently stiff to withstand high load forces, the material must be good to prevent from fatigue fractures when exercising, must have flexibility when fixing complex fractures and have fractures fixed firmly by using connections with bones [6, 10, 12] * Evaluation of sturdy fixation capacity of fractures: The system of locking plate - bone has a higher hardness and durability than the bone condylar buttress plate system According to Jamie Alexander et al (2015) [11], axial compression for fracture of entire distal femur was 4,142.67 ± 178.71 N, hard bone shell bore a maximum force of 456.64 ± 78.63 N/mm, maximum axial compression force for femoral supracondylar fracture was 2,533.57 ± 245.21 N Porous bone shell was subjected to maximum force of 474.4 ± 148.49 N/mm, axial compressive force for femoral intercondylar fracture was 2,728.83 ± 235.83 N, so the system of locking plate - bone with supracondylar fractures withstood the maximum compressive force of 4,010 ± 509.50 N and intercondylar fractures withstood the maximum compressive force of KC-N: 4,620.27 ± 315.85 N that were higher than the axial compression for fracture of entire distal femur The force increment of bending and twisting effect on the plate - bone system of the system of locking plate - bone in both models of supracondylar and intercondylar femoral fractures was higher than that of the system of condylar buttress plate - bone The bending force to break down the linkage of the plate bone system with a mm shift of the locking plate - bone (KA-U: 704.33 ± 110.45 N and KC-U: 699.26 ± 125.60 N) was greater than the condylar buttress plate - bone (LA-U: 505.76 ± 62.83 N and LC-U: 476.05 ± 59,18 N) The torsion force with a mm shift to break the linkage of the locking plate - bone (KA-X: 990.79 ± 166.54 N and KC-X: 1,071.00 ± 222.38 N) was also higher than the condylar buttress plate - bone system (LA-X: 888.84 ± 89.02 N and LC-X: 986.26 ± 116.33 N) on the same sample On the experimental models of compression, bending, torsion of the locking plate - bone system with supracondylar and intercondylar beef femur fractures With intercondylar femoral fracture, compression force KC-N: 4,620.27 ± 315.85 N and twist bending KC-X: 1,071.00 ± 222.38 N of the locking plate - bone system were higher than intercondylar femoral fracture: KA-N: 4,010 ± 509.50 N and KA-X: 990.79 ± 166.54 N, while bending forces were not much different Supracondylar femoral fracture, therefore, some authors had a view that it is possible to combine bone with medullary nail with reverse flow pin, L angle plate, DCS plate [2, 4] , that also achieves therapeutic effect However, with intercondylar femoral fracture, joint breakage, the above-mentioned means of bone combination revealed many disadvantages, now the authors choose to combine bones with the distal femoral locking plate and condylar buttress plate In cases of distal femoral fractures, articular fractures, complex fractures, multiple fragments, fractures in the elderly, fractures in osteoporosis patients, some authors recommend selecting a combination 191 Journal of military pharmaco-medicine no8-2019 of distal femoral locking plate because the locking plate - bone system withstands a high compressive, horizontal bending, torsion force and fixes fractures firmly [8, 9] CONCLUSION Studying firm fracture fixation of the 7hole distal femoral locking compression plate (intercus locking plate type, German pure titanium material, screws made from TiAl6V4 compound), on the type A2 and C2 fracture test models gave results: The bond of plate - bone under compression force of type A2 (KA-N): 4,010.37 ± 509.50 N, type C2: 4,620.27 ± 315.85 N with a 2.5 mm fracture displacement broke The bond of plate bone under horizontal bending force of type A2 (KA-U): 704.33 ± 110.45 N, type C2 (KC-U): 699.26 ± 125.60 N with a mm fracture displacement broke The bond of plate - bone under torsion force of type A2 (KA-X): 990.79 ± 166.54 N, type C2 (KC-X): 1,071.00 ± 222.38 N with a mm fracture displacement broke Comparing on the same testing model of plates with supracondylar fracture and intercondylar fracture in beef femurs, it was found that the system of distal femoral LCP - bone under compression, and bending force was larger than the system of condylar buttress plate - bone 103 Military Hospital Thesis of Master in Medicine Military Medical University Hanoi 2009 Hoang Ngoc Minh, Le The Hung, Pham Dang Ninh, Nguyen Quang Trung Evaluation of treatment results of closed distal femoral fractures using a locking plate Journal of Military Pharmaco-Medicine Military Medical University 2015, 40, topic number of November, pp.63-67 Do Duy Trung Evaluation of treatment results of supracondylar and intercondylar fractures using AO’s condylar plate at 108 Military Central Hospital Thesis of Specialist II Hanoi 2009 Anand J Thakur Intramedullary nailing The Elements of Fracture Fixation Second edition 2007, chapter 5, pp.138-140 Animesh Agarwal Open reduction and internal fixation of the distal femur Operative Techniques in Orthopaedic Trauma Surgery 2011, chapter 43, pp.394-415 Brett D Crist, Gregory J, Della Rocca, Yvonne M Mutha Treatment of acute distal femur fracture Orthopedics 2008, 31 (7) Dirk Wähner, Konrad Hoffmeier et al Distal femur fractures of the alderly: Different treatment options in a biomechanical comporation Injury Int J Care Injuried 2011, 42, pp.655-659 Dirk Wähner, J.H Lange, M Schulze et al The potential of implant augmentation in the treatment of osteoporotic distal femur fractures: A biomechanical study Injury Int J Care Injuried 2013, 44, pp.808-812 REFERENCES 10 Gebhard F, Kinzl L Femur, distal AO Principles of Fracture Management, AO publishing Switzerland 2007, pp.786-799 Than Trong Doan Comments on treatment results of closed fracture of the distal femur with 95° angle plate in Hue Central Hospital Thesis of Specialist II Military Medical University Hanoi 2005 11 Jamie Alexander, Radal P Morris et al Biomechanical evaluation of periprosthetic refractures following distal femur locking plate fixation Injury Int J Care Injuried 2015, 46, pp.2368-2373 Bui Manh Ha Evaluation of treatment results of supracondylar and intercondylar fractures of adult femurs with DCS plate at 12 Kulkarni G.S Locking plate Textbook of Orthopedics and Trauma Second edition 2008, Vol 2, section 16, pp.1433-1454 192 ... femur locking compression plate and condylar buttress plate on the sample of laboratory fracture fixation to grasp the fracture fixation of plates and suggest reasonable postoperative practice... models of supracondylar and intercondylar femoral fractures was higher than that of the system of condylar buttress plate - bone The bending force to break down the linkage of the plate bone system... than the axial compression for fracture of entire distal femur The force increment of bending and twisting effect on the plate - bone system of the system of locking plate - bone in both models of