Evaluation of callus formation in distal femur fractures after carbon fiber composite versus stainless steel plate fixation.

INTRODUCTION: Carbon-fiber-reinforced polyetheretherketone (CFR) composite plates have a more favorable stress modulus than stainless steel (SS) plates that may confer an advantage to bridge plating. The purpose of this study was to compare callus formation after CFR and SS plating of distal femur fractures. METHODS: A retrospective review identified distal femoral fractures treated with CFR (n = 10) and SS (n = 21) plate fixation. Callus formation was measured using the modified Radiographic Union Score for Tibia (mRUST) at 3- and 6-month follow-up by three orthopedic trauma surgeons. Loss of alignment, implant failure, and revision surgeries were reviewed. RESULTS: At 3 months, the mRUST in the CFR and SS groups was 9.0 (range, 6.3-12.3) and 6.9 (range, 4.3-11.7), respectively (p = 0.01). At 6 months, the mRUST in the CFR and SS groups was 11.4 (range, 7.7-16.0) and 10.5 (range, 6.0-15.7), respectively (p = 0.3). CFR and SS groups had a loss of fracture alignment in 1 (10%) and 1 (5%) patient, respectively (p = 0.5), and an unplanned revision surgery in 0 (0%) and 3 (15%) patients, respectively (p = 0.2). All three revisions surgeries in the SS group were for nonunion repair. CONCLUSIONS: Treatment of distal femur fractures with CFR versus SS plating resulted in greater callus formation at 3 months. At 6 months, there was no difference in callus formation between groups. A larger series of patients is necessary to determine if the observed early increased callus formation confers a benefit to clinical outcomes. LEVEL OF EVIDENCE: Therapeutic level III.

Distal radius plate of CFR-PEEK has minimal effect compared to titanium plates on bone parameters in high-resolution peripheral quantitative computed tomography: a pilot study.

BACKGROUND: Carbon-fiber-reinforced poly-ether-ether-ketone (CFR-PEEK) has superior radiolucency compared to other orthopedic implant materials, e.g. titanium or stainless steel, thus allowing metal-artifact-free postoperative monitoring by computed tomography (CT). Recently, high-resolution peripheral quantitative CT (HRpQCT) proved to be a promising technique to monitor the recovery of volumetric bone mineral density (vBMD), micro-architecture and biomechanical parameters in stable conservatively treated distal radius fractures. When using HRpQCT to monitor unstable distal radius fractures that require volar distal radius plating for fixation, radiolucent CFR-PEEK plates may be a better alternative to currently used titanium plates to allow for reliable assessment. In this pilot study, we assessed the effect of a volar distal radius plate made from CFR-PEEK on bone parameters obtained from HRpQCT in comparison to two titanium plates. METHODS: Plates were instrumented in separate cadaveric human fore-arms (n = 3). After instrumentation and after removal of the plates duplicate HRpQCT scans were made of the region covered by the plate. HRpQCT images were visually checked for artifacts. vBMD, micro-architectural and biomechanical parameters were calculated, and compared between the uninstrumented and instrumented radii. RESULTS: No visible image artifacts were observed in the CFR-PEEK plate instrumented radius, and errors in bone parameters ranged from -3.2 to 2.6%. In the radii instrumented with the titanium plates, severe image artifacts were observed and errors in bone parameters ranged between -30.2 and 67.0%. CONCLUSIONS: We recommend using CFR-PEEK plates in longitudinal in vivo studies that monitor the healing process of unstable distal radius fractures treated operatively by plating or bone graft ingrowth.

Biomechanical evaluation of locking versus nonlocking 2.0-mm malleable L-miniplate fixation of simulated caudal mandibular fractures in cats.

OBJECTIVE: To evaluate the biomechanical properties of the mandibles of cats with experimentally created osteotomies simulating oblique ramus fractures, which were stabilized with malleable L-miniplates with either locking screws [locking construct (LC)] or nonlocking screws [nonlocking construct (NLC)], compared with those for intact mandibles. SAMPLES: 20 mandibles from 10 adult cat cadavers. PROCEDURES: A block study design was adopted to allocate the mandibles of each cadaver to 2 of the 3 test groups (LC, NLC, or intact mandible). Mandibles within each cadaver were allocated systematically to a test group. For mandibles assigned to an LC and an NLC, a complete oblique osteotomy was performed from the mid rostral aspect of the ramus in a caudoventral direction. All mandibles were loaded in a single-load-to-failure test through cantilever bending. Load and actuator displacement were recorded simultaneously. Mode of failure and radiographic evidence of damage to tooth roots and the mandibular canal were evaluated. Biomechanical properties were compared among the groups. RESULTS: No iatrogenic tooth root damage was evident, but all mandibles with an LC and an NLC had evidence of screw invasion into the mandibular canal. Plated mandibles had significantly less stiffness and bending moment than intact mandibles. Stiffness was not significantly different between the LC and the NLC; the NLC had a greater bending moment at failure than the LC. The pre-yield stiffness of plated mandibles decreased when the number of screw holes overlapping the mandibular canal increased. CLINICAL RELEVANCE: The use of a malleable L-miniplate in a caudal mandibular fracture model is feasible. Both the LC and the NLC were inferior mechanically to intact mandibles. Type of construct used did not affect the construct stiffness significantly in tested mandibles.

Mechanical aspects of a multidirectional, angular stable osteosynthesis system and comparison with four conventional systems.

BACKGROUND: Following open reduction, internal fixation of fractures of the mandible is predominantly achieved using plates and screws. Today, a multitude of osteosynthesis systems are available on the market. One therapy modality, primarily developed for orthopaedic surgery, is using angular stable osteosynthesis plate systems. The dominating principle of these is the bond between screw and plate following insertion. This principle of an "internal fixateur" results in a more stable fixation of the fragments associated with less compression of the bone surfaces. MATERIAL: A new multidirectional osteosynthesis system (TiFix=Smartlock, Hamburg - Germany) was modified to fit the maxillofacial region and compared with four other well established osteosynthesis systems developed by Mondial, Medicon, Synthes, Leibinger-Stryker, one of these (Unilock by Synthes) being also angular stable. The resistance to deformation in varying directions was investigated following fixation in four different materials. RESULTS: The TiFix system proved more resistant to deformation even when mounted with fewer screws than the non-angular stable systems. CONCLUSION: This system results in greater stability even when fewer screws are used. For the clinician this means smaller access incisions, less soft tissue trauma, better aesthetic results, decreased duration of operation and a reduction of costs.

In vitro evaluation of the resistance of three types of fixation to treat fractures of the mandibular angle.

The purpose of this study was to compare the mechanical resistance of three different plates used to treat fractures of the mandibular angle: a regular 4-hole plate, a longer 4-hole plate (both positioned using the Champy technique), and a 3-dimensional plate positioned over the oblique line. Three equal groups of replicas of human dentate mandibles made out of polyurethane resin were used (n=21 in each group). The force was applied perpendicular to the occlusal plane at a rate of 2mm/minute at three different points: the first molar on the sectioned side; the first molar on the contralateral side; and between the central incisors. This was followed by a resistance-to-load test. The two varying factors (type of plate and site-of-load application) were tested by analysis of variance, and probabilities of less than 0.05 were accepted as significant. There were no significant differences between the subgroups, or between the mean values of the different types of plates (p=0.925). The three types of plates showed similar mechanical behaviour, which showed that the 3-dimensional plates positioned over the oblique line can produce mechanical scores similar to those of conventional plates.

The study of physicochemical properties of stabilizing plates removed from the body after treatment of pectus excavatum.

This paper presents the results of a physicochemical surface study and clinical observation of a new generation of plates for the treatment of pectus excavatum. Analysis of the data allowed us to investigate the effect of implant design and condition of their surface on the results of treatment of pectus excavatum. In the study, we performed an analysis of clinical data, obtained after a suitable period of treatment with the use of implants, as well as a study of physicochemical properties of stabilizing plates after their removal from the body. Surface roughness, the surface wettability and corrosion resistance were measured, and the results were compared with clinical observations. When removing the plates we found only slight inflammatory-periosteal reactions around the wire fixing transverse stabilizing plates to the ribs and locking the base plate correcting the distortion. The corrective plates did not shift or rotate during the entire treatment period, giving an optimal, oval and natural shape of the chest. The obtained values of the parameters investigated indicate that the reduction in resistance to pitting corrosion occurred in the areas where laser marking was made to identify the plate. The remaining plates, in spite of mechanical damage of the surface, were characterized by good corrosion resistance, a fact which is confirmed by the results of clinical evaluation.

Treatment of condylar fractures with an intraoral approach using an angulated screwdriver: results of a multicentre study.

BACKGROUND: This multicentre study aimed to investigate long-term radiographic and functional results following the treatment of condylar fractures using an angulated screwdriver system and open rigid internal fixation with an intraoral surgical approach. METHODS: Twenty-nine patients with a total of 32 condylar fractures were evaluated. The patients were investigated prospectively based on the following variables: age, sex, aetiology, side, location and classification of the fracture, degree of displacement, associated fractures, surgical approach, oral health status, type of osteosynthesis plate, duration of surgery, mouth-opening, complications, and duration of follow-up. RESULTS: The fractures were classified as subcondylar (n = 25) or condylar neck (n = 7). Mean patient age was 36.38 ± 16.60 years. The median duration of postoperative follow-up was 24.39 ± 13.94 months. No joint noise, weakness of the facial nerve, joint pain, or muscle pain was observed. An additional retromandibular approach was necessary to enable the treatment of one subcondylar fracture with medial displacement. CONCLUSION: Subcondylar or condylar neck fractures with medial or lateral displacement can be treated using an intraoral approach with satisfactory results with the advantages of the absence of visible scarring, the avoidance of facial nerve injury, and the ability to obtain rapid access to the fracture.

A comparative study of miniplates used in the treatment of mandibular fractures.

The purposes of this study were to investigate the differences in mechanical properties of major miniplating systems used for noncompression miniplate osteosynthesis of mandibular fractures and to determine whether these properties influence treatment outcome. The study was conducted in two parts. First, six of the major miniplate systems currently used at the Royal Adelaide Hospital were subjected to bending tests at the University of Adelaide Engineering Department to quantify the relative stiffness of each plate. Second, a prospective sample of patients presenting with mandibular fractures was analyzed. These patients were treated with a variety of the miniplating systems. The results of treatment as a whole were compared to identify any direct benefit consequent on the miniplate selected. While significant differences in stiffness were identified between the plating systems, no significant differences in treatment outcome were identified, between the noncompression plates employed. Since no observable benefits have been identified by choice of miniplate, selection should be based on surgical preference, biocompatibility, CT compatibility and unit cost. Because of the variations in materials, design, properties, CT compatibility, and unit cost, it is important not to regard all miniplates as equal and interchangeable.

A comparative study on four screw-plate locking systems in sheep: a clinical and radiological study.

Four mandibular screw-plate locking systems were studied in sheep. Three to four centimetres angular continuity resections of the mandible were performed and the defects bridged with pre-bent angular reconstruction plates fixed with four screws in the body part and three in the ramus. Each type was used four times. Clinical and radiological examinations were carried out 1 and 2 months later. All sheep were able to eat and ruminate normally throughout the postoperative period. Radiology revealed that 6/16 plates and 5/112 screws fractured during the follow-up period. In one type, no fracture occurred. Screw fracture was confined to just one reconstruction system. Six of 16 mandibles showed slight to moderate bone resorption under the plate. The results point to the internal shortcomings of the systems tested.

Skeletal stability and condylar position related to fixation method following mandibular setback with bilateral sagittal split ramus osteotomy.

PURPOSE: To investigate postoperative intersegmental displacement and relapse following bilateral sagittal split ramus osteotomy (BSSRO) by comparing three different fixation methods: group A (sliding plate), group B (miniplate) and group C (bicortical screws). MATERIALS AND METHODS: The present retrospective study included 55 patients with mandibular prognathism who were treated with BSSRO. To evaluate skeletal changes, cone-beam computed tomography was taken before surgery (T0), three days after surgery (T1), and 6 months after surgery (T2). Differences among the three groups were assessed using a one-way analysis of variance, where P < 0.05 was accepted as statistically significant. RESULTS: There were no significant differences among the three groups in demographic data and the amount of mandibular setback. In skeletal changes and condylar axis changes, there were no statistically significant differences among the three groups. However, there were statistically significant postoperative skeletal changes in group C (bicortical screws) at all landmarks. The mean horizontal relapse rate was 1.9% in group A (sliding plate); 4.8% in group B (miniplate); and 15.4% in group C (bicortical screws). CONCLUSION: The sliding plate system has good adaptability to the proximal segment after mandibular setback with BSSRO, and behaves according to semi-rigid fixation principles.

Maxillary stability after Le Fort I osteotomy using three different plate systems.

The purpose of this study was to compare postoperative changes in maxillary stability after Le Fort I osteotomy in three groups: with an unsintered hydroxyapatite (u-HA)/poly-L-lactic acid (PLLA) plate; a PLLA plate; and a titanium plate. Subjects comprised 60 Japanese patients diagnosed with mandibular prognathism. All patients underwent Le Fort I osteotomy and bilateral sagittal split ramus osteotomy. All patients were randomized in groups of 20 to a u-HA/PLLA group, a PLLA plate group and a titanium plate group. Changes in postoperative time intervals between the plate groups were compared using lateral and posteroanterior cephalography. The uHA/PLLA group had significantly larger values than the PLLA group regarding change of mx1-S perpendicular to SN between 3 and 12 months (T3) (P=0.0269). The uHA/PLLA group had a significantly larger value than the PLLA group regarding change of S-A perpendicular to SN between baseline and 1 month (T1) (P=0.0257). There was no significant difference in the other measurements. This study suggests that maxillary stability with satisfactory results could be obtained in the u-HA/PLLA, PLLA plate and titanium plate groups, although there was a slight difference between the u-HA/PLLA and PLLA plate systems in Le Fort I osteotomy.

Comportamento mecânico de diferentes tipos de miniplacas para ancoragem esquelética no tratamento da mordida aberta anterior / Mechanical behavior of different miniplate designs for skeletal anchorage in the previus open bite

Situações clínicas que envolvam discrepâncias moderadas e que teriam como opção terapêutica o tratamento orto-cirúrgico, por meio da cirurgia ortognática, podem beneficiar-se da utilização da ancoragem esquelética buscando resultados satisfatórios e com menor morbidade ao paciente. O tratamento da mordida aberta anterior no paciente adulto é uma das situações em que as miniplacas podem oferecer uma ancoragem esquelética capaz de permitir o seu tratamento sem a realização da cirurgia ortognática. O objetivo deste trabalho foi verificar, por meio de análise por elementos finitos, distribuição de tensão e o comportamento de diferentes desenhos de miniplacas, por meio dastensões recebidas e deslocamento sofrido, simulando uma situação clínica de ancoragem esquelética para o tratamento de mordida aberta anterior no adulto. Em um modelo virtual foram aplicadas forças intrusivas de 2, 4 e 6N em molares superiores, tendo como ancoragem miniplacas com formatos T, Y, e I instaladas na região da crista zigomática alveolar. Verificou-se o deslocamento, tensão máxima principal e tensão de Von Mises, de acordo com o formato do dispositivo de ancoragem. As configurações das placas resultaram em diferentes intensidades de stress no osso, na placa e no deslocamento, porém essas tensões se localizaram sempre nas mesmas regiões dentro do limite fisiológico. A placa T obteve comportamento mais indesejado e a placa Y se mostrou mais próxima do ideal(AU)

Clinical situations that involve moderate discrepancies and that would have as a therapeutic option the ortho-surgical treatment, through orthognathic surgery, can benefit from the use of skeletal anchorage seeking satisfactory results and lower morbidity to the patient. The treatment of anterior open bite in the adult patient is one of the situations in which the miniplates can offer a skeletal anchorage capable of allowing its treatment without performing orthognathic surgery. The objective of this work was to verify, through finite element analysis, the bone stress and the behavior of different miniplate designs, through the tensions received and displacement suffered, simulating a clinical situation of skeletal anchorage for the treatment of anterior open bite in the adult. In a virtual model, intrusive forces of 2, 4 and 6N were applied in upper molars, and miniplates with T, Y, and I formats were anchored in the region of the zygomatic abutment. The displacement, main maximum voltage and voltage of Von Mises were checked according to the shape of the anchoring device. The plaque configurations resulted in different stresses in bone, plaque and displacement, but these stresses were always located in the same regions within the physiological limit. The T plate obtained more unwanted behavior and the Y plate showed to be closer to the ideal(AU)

Biomechanical comparison of a new technique of mandibular angle fractures: biplanar and bicortical superior proximal 3 holes and bicortical inferior plate fixation.

Miniplates have been used for mandibular angle fractures during the past 2 decades. The technique of placing single miniplate at the upper border based on the tension lines of the fracture was proposed by Michelet and Champy. The need for a second miniplate to be applied to the lower mandible has been discussed recently. Biomechanical comparison of biplanar and monoplanar dual-miniplate fixation techniques was investigated by Haug. Our hypothesis is in dual-miniplate fixation; the proximal 3 holes of superior border miniplate could be fixated by bicortical screws. The first 2 are at the proximal bone segment and are not related to the tooth and also superior to the alveolar nerve. Generally, the third molar tooth is extracted because it is at the fracture site. Hence, the proximal third hole could also be fixated by bicortical screws. We define a biplanar dual-miniplate technique in which the lower plate and the proximal 3 holes of the upper plate are fixated by bicortical screws. We have designed a study for biomechanical comparison of our method and popular types of mandibular fixation methods.

Invited review: small versus large plate fixation of mandibular fractures.

BACKGROUND AND OBJECTIVES: Since the introduction of antibiotics in the late 1940s, open reduction and internal fixation (ORIF) gradually replaced various dental splints and devices as a means of providing additional reduction and fixation of mandibular fractures. Stainless steel wire has been recently replaced by plate-and-screw fixation. When properly utilized, this method provides convalescent function without maxillomandibular fixation (MMF). The purpose of this article is to review the evolution of small versus large plate fixation of mandibular fractures. METHODS AND MATERIALS: In the context of reports in the literature and 26 years of clinical experience, the authors review the types of mandibular rigid fixation, healing of fractures, morbidity of fracture repair, indications for rigid fixation, and evolution of techniques of treatment. RESULTS AND/OR CONCLUSIONS: Although numerous devices and techniques--bone clamps, intra- and extramedullary K-wires, metallic mesh, and other means--have been used and abandoned, modern plate and screw systems, if not the standard of care, have become widely accepted and used.

Fracture of mandibular reconstruction plates used after tumor resection.

PURPOSE: We assessed the incidence of fractured plates after primary temporary AO plate reconstruction of the mandible following tumor resection. PATIENTS AND METHODS: One hundred ten patients were retrospectively evaluated according to the extent of the tumor, anatomic location of the reconstruction, type of plate, additional use of radiotherapy or flap surgery (or both), and the incidence of fractured plates. RESULTS: Fractured plates occurred in 8 of 110 patients. Most occurred less than 6 months after surgery. All of the 8 patients had a malignant tumor; 2 had received radiation therapy and 4 had skin flaps placed. The fractured plate was the straight type in 1 patient and the angular type in 7 patients. Among patients who had fractured plates, the average number of remaining teeth was 12.8 in the maxilla and 9.5 in the mandible. CONCLUSIONS: Fractured plates were more common among patients with oral cancer with a segmental defect that did not cross the midline in whom an angular-type plate was used and no bone grafting was performed.

Treatment methods for fractures of the mandibular angle.

Fractures of the mandibular angle are plagued with the highest rate of complication of all mandibular fractures. Over the past 8 years, the following six accepted forms of treatment for these fractures were performed on an indigent inner-city population: closed reduction or intra-oral open reduction and nonrigid fixation; extraoral open reduction and internal fixation with an AO/ASIF reconstruction bone plate; and intraoral open reduction and internal fixation using either two 2.0 mm minidynamic compression plates, two 2.4 mm mandibular dynamic compression plates, two noncompression miniplates, or a single noncompression miniplate. This article reviews the results of those treatment modalities when used for the same patient population at one hospital. Results show that the use of either an extraoral open reduction and internal fixation with the AO/ASIF reconstruction plate or intraoral open reduction and internal fixation using a single miniplate was associated with the fewest complications.