Comparative experimental study of the biomechanical properties of retrograde tibial nailing and distal tibia plate in distal tibia fracture.

Objective: A biomechanical comparative analysis was conducted to evaluate the retrograde tibial nailing (RTN) and distal tibia plate techniques for the treatment of distal tibia fractures. Methods: Fourteen fresh adult tibia specimens were selected, consisting of seven males and seven females aged 34-55 years. The specimens were randomly divided into two groups (Group A and Group B) using a numerical table method, with seven specimens in each group. Group A underwent internal fixation of distal tibial fractures using RTN, while Group B received internal fixation using a plate. The axial compression properties of the specimens were tested in the neutral positions under pressures of 100, 200, 300, 400, and 500 N. Additionally, the torsional resistance of the two groups was assessed by subjecting the specimens to torques of 1.0, 2.0, 3.0, 4.0, and 5.0 N m. Results: At pressures of 400 and 500 N, the axial compression displacement in Group A (1.11 ± 0.06, 1.24 ± 0.05) mm was significantly smaller than that in Group B (1.21 ± 0.08, 1.37 ± 0.11) mm (p = 0.023, 0.019). Moreover, at a pressure of 500 N, the axial compression stiffness in Group A (389.24 ± 17.79) N/mm was significantly higher than that of the control group (362.37 ± 14.44) N/mm (p = 0.010). When subjected to torques of 4 and 5 N m, the torsion angle in Group A (2.97° ± 0.23°, 3.41° ± 0.17°) was significantly smaller compared to Group B (3.31° ± 0.28°, 3.76° ± 0.20°) (p = 0.035, 0.004). Furthermore, at a torque of 5 N m, the torsional stiffness in Group A (1.48 ± 0.07) N m/° was significantly higher than that in Group B (1.36 ± 0.06) N·m/° (p = 0.003). Conclusion: The results obtained from the study demonstrate that the biomechanical performance of RTN outperforms that of the distal tibial plate, providing valuable biomechanical data to support the clinical implementation of RTN.

Modified application of distal medial tibial locking plate as an alternative for fixation of an extraarticular distal-third diaphyseal humerus fracture.

INTRODUCTION: Surgical management of Extraarticular Distal-third diaphyseal Humerus Fracture (EADHF) poses a dilemma in terms of surgical approach, implant selection and position of the implant due to the availability of various pre-contoured implants and plate configurations. Various studies have described a modified application of anatomic locking plates as a satisfactory method of fixation in the surgical management of EADHF. CASE PRESENTATION: This report discusses the modified application of anatomic Distal Medial Tibial locking Plate (DMTP) as an alternative strategy in fixation of an acute extraarticular distal-third diaphyseal fracture of the humerus in a 45-years-old female patient. Bony union was achieved successfully without any malalignment and the patient showed a full recovery with an excellent clinical and outcome at 2-years follow-up. CONCLUSION: In EADHF, the use of 3.5 mm DMTP is advantageous as it offers rigid fixation by insertion of more number of 3.5 mm locking bicortical screws and stability in both columns. This promotes biological fracture healing, low rate of complication, early return to work with improvement in clinical function. Therefore, we recommend that pre-contoured 3.5 mm DMTP can be successfully used as an alternative fixation choice for the treatment of EADHF.

Plating of pilon fractures based on the orientation of the fibular shaft component: A biomechanical study evaluating plate stiffness in a cadaveric fracture model.

OBJECTIVES: To evaluate mechanically superior method of pilon fracture fixation by comparing axial stiffness between anterolateral and medial tibial locking plates in a cadaveric fracture model. METHODS: Eight matched pairs of fresh frozen cadaver specimens (lower limb after through-knee disarticulation) were used to eliminate confounder of bone quality. Simulated pilon fractures were created so that each pair represented either varus or valgus fracture pattern (AO 43-A2) with associated fibular fractures (transverse or comminuted). Specimens were plated with DePuy anterolateral or medial locking plate and axial load applied, measuring displacement at the fracture site. Each lower extremity was tested with a fracture wedge in place and removed to mimic comminution. Average force at which failure occurred was compared between the two fixation methods, for varus and valgus fracture pattern respectively, with the use of a Mann-Whitney U test. RESULTS: On average, medial plate fixation of varus fractures resulted in 2.27 times (range of 1.6-3.9) greater load prior to failure as compared to anterolateral plate. Similarly, valgus simulated fractures tolerated 1.6 times (range 1.12-2.34) higher force prior to failure if anterolateral plate was applied versus medial plate. Analysis utilizing the Mann-Whitney U test for fracture patterns vs plate configuration approached statistical significance (p = 0.081 varus failure and p = 0.386 valgus failure). CONCLUSIONS: Lateral plate fixation is biomechanically superior for pilon fractures resulting from valgus force as evident by comminuted fibular fracture. Similarly, medial plate location resulted in improved stiffness in compression for varus type fractures, evident by transverse fibular fracture. We approached statistical significance, however our lack of power regarding adequate sample size is an issue that is consistent with other biomechanical studies in this area.

Evaluation of Fibular Fracture Type vs Location of Tibial Fixation of Pilon Fractures.

BACKGROUND: Comminuted fibular fractures can occur with pilon fractures as a result of valgus stress. Transverse fibular fractures can occur with varus deformation. No definitive guide for determining the proper location of tibial fixation exists. The purpose of this study was to identify optimal plate location for fixation of pilon fractures based on the orientation of the fibular fracture. METHODS: One hundred two patients with 103 pilon fractures were identified who were definitively treated at our institution from 2004 to 2013. Pilon fractures were classified using the AO/OTA classification and included 43-A through 43-C fractures. Inclusion criteria were age of at least 18 years, associated fibular fracture, and definitive tibial plating. Patients were grouped based on the fibular component fracture type (comminuted vs transverse), and the location of plate fixation (medial vs lateral) was noted. Radiographic outcomes were assessed for mechanical failures. RESULTS: Forty fractures were a result of varus force as evidenced by transverse fracture of the fibula and 63 were due to valgus force with a comminuted fibula. For the transverse fibula group, 14.3% mechanical complications were noted for medially placed plate vs 80% for lateral plating ( P = .006). For the comminuted fibular group, 36.4% of medially placed plates demonstrated mechanical complications vs 16.7% for laterally based plates ( P = .156). Time to weight bearing as tolerated was also noted to be significant between groups plated medially and laterally for the comminuted group ( P = .013). CONCLUSIONS: Correctly assessing the fibular component for pilon fractures provides valuable information regarding deforming forces. To limit mechanical complications, tibial plates should be applied in such a way as to resist the original deforming forces. Level of Evidence Level III, comparative study.

Ability of modern distal tibia plates to stabilize comminuted pilon fracture fragments: Is dual plate fixation necessary?

OBJECTIVES: The purpose of this study was to examine the screw trajectory of ten commercially available distal tibia plates and compare them to common fracture patterns seen in OTA C type pilon fractures to determine their ability to stabilize the three most common fracture fragments while buttressing anterolateral zones of comminution. HYPOTHESIS: We hypothesized that a single plate for the distal tibia would fail to adequately stabilize all three main fracture fragments and zones of comminution in complex pilon fractures. METHODS: Ten synthetic distal tibia sawbones models were used in conjunction with ten different locking distal tibia plate designs from three manufacturers (Depuy Synthes, J&J Co, Paoli, PA; Smith & Nephew, Memphis, TN; and Stryker, Mawa, NJ). Both medial and anterolateral plates from each company were utilized and separately applied to an individual sawbone model. Three implants allowing variable angle screw placement were used. The location of the locking screws and buttress effect 1cm above the articular surface was noted for each implant using axial computed tomography (CT). The images were then compared to a recently published "pilon fracture map" using an overlay technique to establish the relationship between screw location and known common fracture lines and areas of comminution. Each of the three main fragments was considered "captured" by a screw if it was purchased by at least two screws thereby controlling rotational forces on each fragment. RESULTS: Three of four anterolateral plates lacked stable fixation in the medial fragment. Of the 4 anterolateral plates used, only the variable angle anterolateral plate by Depuy Synthes captured the medial fragment with two screws. All four anterolateral plates buttressed the area of highest comminution and had an average of 1.25 screws in the medial fragment and an average of 3 screws in the posterolateral fragment. All five direct medial plates had variable fixation within anterolateral and posterolateral fragments with an average of 1.8 screws in the anterolateral fragment and an average of 1.3 screws in the posterolateral fragment. The Depuy Synthes variable angle anterolateral plate allowed for fixation of the medial fragment with two screws while simultaneously buttressing the zone of highest comminution and capturing both the anterolateral and posterolateral fragments with five and three screws respectively. The variable angle anteromedial plate by Depuy Synthes captured all three main fracture fragments but it did not buttress the anterolateral zone of comminution. CONCLUSION: In OTA 43C type pilon fractures, 8 out of 10 studied commercially available implants precontoured for the distal tibia, do not adequately stabilize the three primary fracture fragments typically seen in these injuries. Anterolateral plates were superior in addressing the coronal primary fracture line across the apex of the plafond, and buttressing the zone of comminution. None of the available plates can substitute for an understanding of the fracture planes and fragments typically seen in complex intra-articular tibia fractures and the addition of a second plate is necessary for adequate stability. LEVEL OF EVIDENCE: Level IV.