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.

Effects of Bone-Plate Material on the Predicted Stresses in the Tibial Shaft Comminuted Fractures: A Finite Element Analysis.

PURPOSE: In this research, low modulus carbon fiber (CF)-reinforced polyetheretherketone composite plates (CF-PEEK plates) were compared with traditional metal plates using finite element analysis to establish a reference for clinical application. MATERIAL AND METHODS: Plates of stainless steel, titanium alloy (Ti6Al4V), or CF-PEEK with different carbon fiber reinforcement ratios (CF30, CF50, and CF60) were used to fix the tibial shaft comminuted fracture. The maximum stress, the maximum displacement of fracture and the stress shielding of cortex bone were analyzed. RESULTS: Under 200 N axial compression, the maximum displacement was measured in the CF30 plate (4.62 mm) and the minimum in the stainless steel plate (0.23 mm). The stress shielding rates of stainless steel, titanium, CF30, CF50, and CF60 plates were 59.4%, 54.4%, 23.75%, 48.75% and 66.25%. Under 700 N axial compression, the internal fixation by the CF30 plate failed. Among the other 4 plates, the maximum displacement was measured in the CF50 plate (2.52 mm) and the minimum in the stainless steel plate (0.78 mm). The stress shielding rate of plates made of stainless steel, titanium, CF50, and CF60 were 57.1%, 52.0%, 48.1%, and 67.8%. CONCLUSIONS: CF50 plates can be safely used in the tibial shaft comminuted fracture. The micromotion in the CF50 and CF60 plate was more beneficial to callus formation and fracture healing. The stress shielding of the cortex bone under the CF50 plate was the lowest. The finite element analysis indicated that the CF-PEEK material is worthy of further study because of its biomechanical advantages.

The comparison of single plate and double plate fixation methods for treatment of humeral shaft nonunions.

OBJECTIVES: This study aims to evaluate the early- and mid-term shoulder and elbow functions and compare the union rates after the application of single plate and double plate for the treatment of humerus shaft nonunions. PATIENTS AND METHODS: This retrospective study included 56 patients (36 males, 20 females; mean age 53.8±9.5; range, 28 to 68 years) treated with double plate (n=25) and single plate (n=31) osteosynthesis between October 2012 and January 2016. Surgical treatment of the nonunion was applied in the fourth month after the fracture at the earliest. Autograft taken from the iliac bone was applied during the surgery in all patients. Evaluation was performed using The University of California at Los Angeles (UCLA) Shoulder Score, Mayo Elbow Performance Score (MEPS), Visual Analog Scale (VAS), Constant Shoulder Score, and Disabilities of the Arm Shoulder and Hand (DASH) questionnaire. RESULTS: The mean postoperative follow-up time was 40.7±9.6 (range, 25 to 58) months. No statistically significant difference was determined in respect of time to union, follow-up time, DASH questionnaire score, UCLA Shoulder Score, VAS, MEPS and Constant Shoulder Score after union in the comparison of the two groups (p>0.05). In the examination of postoperative early (three months) recovery phase of shoulder and elbow functions, statistically significant superior scores were obtained in the double plate group for MEPS (double plate median=85 [min 75-max 90], single plate median=75 [min 70-max 85]) and Constant Shoulder Score (double plate median=89 [min 85-max 92], single plate median=81 [min 75-max 90]) (p<0.001). CONCLUSION: There was no statistically significant difference in terms of time to union and union rates between single plate and double plate fixations for surgical treatment of humeral shaft nonunions. However, superior clinical results were obtained in the early recovery phase of shoulder and elbow functions with double plate fixation.

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.

Hook versus locking plate fixation for Neer type-II and type-V distal clavicle fractures: a retrospective cohort study.

PURPOSE: This study examined the outcomes and complications after treatment of unstable distal clavicle fractures with hook or locking plate fixation. METHODS: A retrospective search was performed of all acute distal clavicle fractures treated with open reduction and internal fixation from 2009 to 2019 at a Level I trauma center. Patients were separated into hook and locking plate fixation groups. Rates of union, complications, and reoperation, were extracted. QuickDASH (Disabilities of Arm, Shoulder, and Hand) scores were determined. RESULTS: Thirty-one patients met the inclusion criteria and were included in the study. Of these, 12 patients were treated with hook plates and 19 were treated with locking plates. All fractures healed without loss of reduction, regardless of implant selection. There were no immediate or long-term complications in either group. 83% of hook plate patients underwent planned implant removal, while 37% of locking plate patients requested implant removal secondary to irritation. QuickDASH scores were comparable and excellent in both groups. CONCLUSIONS: Hook and locking plate fixation for Neer type-II and type-V distal clavicle fractures have comparably high rates of union. Hook plates were removed routinely per protocol, while locking plates were removed only if symptomatic and occurred significantly less often.

Arthrodesis of the equine proximal interphalangeal joint: a biomechanical comparison of 2 different LCP systems.

OBJECTIVE: This study compares the mechanical stability and surgical usability of 2 locking plate systems (Kyon ALPS-20 and Synthes PIP-LCP system) for arthrodesis of the equine proximal interphalangeal joint (PIJ). MATERIAL AND METHODS: The experimental ex vivo study included 6 pairs of cadaver distal limbs (n = 12). All specimens were derived from Warmblood horses of various ages that were euthanized for non-orthopedic reasons. Of the 12 limbs collected, 3 left and 3 right distal limb specimens were randomly assigned to each system for implantation. Two abaxial 4.5-mm cortical screws were inserted transarticularly in all cases. Both systems were implanted according to the manufacturer's instructions with the plates placed centrally between the 2 transarticular screws. The ALPS-20 systems were implanted using Kyon B-6.4-mm monocortical locking screws in all positions. The LCP systems were implanted axially using 2 Synthes 5-mm locking screws in the proximal and distal positions, with a standard 4.5-mm cortical screw inserted in the middle position. All constructs underwent CT-scans after implantation and biomechanical testing to detect implant deformation. Uniaxial mechanical loading was applied via a servo-hydraulic test system at a test speed of 50 mm/s, up to a maximum displacement of 80 mm. The resulting load-displacement curves were used to calculate yield point, stiffness, and maximum force for each construct. The measured values were evaluated for statistical significance (p < 0.05) between the 2 plate systems via one-factor ANOVA (Tukey test). The statistical power was verified for yield force, stiffness, and maximum load. RESULTS: No statistically significant differences between the 2 preparation groups were calculated across all of the measured parameters (p > 0.05). The ALPS system implants showed no signs of deformation, either in the plates or the screws. In contrast, the LCP demonstrated visible deformation, which had already occurred at the time of implantation from the tightening of the middle screw, as well as during the subsequent testing of the implants. After biomechanical testing, deformations ranging between 3.1° and 7.0° were measured in 4 LCPs. A total implant failure was observed for 2 LCPs. CONCLUSION AND CLINICAL RELEVANCE: Both systems demonstrated comparable mechanical properties in the present study's ex vivo test model for equine PIJ arthrodesis. As such, the Kyon ALPS-20 may be a good alternative to the Synthes LCP for equine PIJ arthrodesis.

Treatment of distal radius fractures with palmar plates and locking screws. Comparisson of two different types of plate.

Various plating systems are available to fix distal radius fractures, each with a specific design. The purpose of this study was to compare radiological outcome and complications of the Variable Angle LCP Plate 2.4-mm (DePuy Synthes) with the VariAx volar locking plate (Stryker). One hundred patients (103 wrists) operated on for a distal radius fracture were retrospectively reviewed with a mean follow-up of 3.5 years. Seventy-three wrists were treated with a DePuy Synthes plate and 30 with a VariAx plate. The overall complication rate was 32%. Nineteen cases underwent revision surgery, 18 had malunion and 3 complex regional pain syndrome. Complicaton rate was 43% with DePuy Synthes plates and 27% with Variax plates, but the difference was not significant.

Comparison of implant failure rates of different plates for midshaft clavicular fractures based on fracture classifications.

BACKGROUNDS: The aim of our study was to investigate failure rates of reconstruction plate and non-reconstruction plate, and find the best strategy for implant selection for different fracture types for midshaft clavicular fractures. PATIENTS AND METHODS: Two hundred twenty-six consecutive patients with midshaft clavicular fractures who received open reduction and plate fixation during Jan 2012 to July 2017 were reviewed. The correlations between implant failure rates and risk factors including demographic data, fracture classifications, and implant types were analyzed. RESULTS: AO/OTA fracture classification and plate types are the most important factors affecting implant failure for midshaft clavicular fractures. Reconstruction plate had a significantly higher failure rate (53%) than that of non-reconstruction plates (3%) in comminuted midshaft clavicular (AO/OTA 15-2C) fractures (P value < 0.01). However, the difference was not significant in AO/OTA 15-2A and 2B classifications. CONCLUSION: Patients with comminuted midshaft clavicular (AO/OTA 15-2C) fractures treated with reconstruction plates had very high implant failure rates compared to non-reconstruction plates. We suggested that patients with comminuted midshaft clavicular (AO/OTA 15-2C) fractures treated with reconstruction plates need more protection and more frequent follow-up in the postoperative period.

Ex Vivo Biomechanical Comparison of Titanium Locking Plate, Stainless Steel Nonlocking Plate, and Tie-in External Fixator Applied by a Dorsal Approach on Ostectomized Humeri of Pigeons (Columba livia).

To compare the bending strength of a locking plate (LP), nonlocking plate (NLP), and an external skeletal fixator intramedullary pin (ESF-IM) tie-in fixation applied by a dorsal approach in an avian humerus fracture model, 5 left humeri obtained from pigeon (Columba livia) cadavers were randomly assigned to each repair technique (n = 15). The ESF-IM group was repaired with a 0.062-inch intramedullary pin tied-in with two 0.035-inch positive profile transfixation pins using acrylic filled plastic tubing. The LP group was repaired with a dorsally applied titanium 1.6-mm screw 7-hole locking plate (1 bicortical and 2 monocortical screws in each segment). The NLP group was repaired with a dorsally applied 6-hole stainless steel 1.5-mm dynamic compression plate (all bicortical screws). All constructs were applied before complete ostectomy to allow perfect reconstruction. Constructs were cyclically tested nondestructively for 1000 cycles in four-point bending before being tested to failure. Outcome measures included stiffness, strength, and strain energy. All specimens cycled without failure. The ESF-IM specimens were significantly stiffer and stronger than the plated repair groups. Plated constructs had significantly higher strain energies than ESF-IM. LP and NLP were of equal stiffness, strength, and strain energies. This study demonstrated that bending biomechanical properties of the ESF-IM configuration were superior to those of the dorsal plate fixation. Exact properties of fixation required to facilitate avian fracture healing are largely unknown. Further study, including assessments of optimal plate position and configuration, and torsional and in vivo studies in avian species are warranted.

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)

Repair of a Tibiotarsal Fracture in a Pomeranian Goose ( Anser anser) With a Locking Plate.

A 2-year-old Pomeranian goose ( Anser anser) weighing 8.1 kg was examined because of non-weight-bearing lameness of the right limb. A closed, transverse, diaphyseal fracture of the distal third of the right tibiotarsus with a craniolateral displacement of the distal fragment was diagnosed radiographically. Surgery under general anesthesia was performed to repair the fracture with a 14-hole, 2.7-mm locking plate fixed with 6 screws in a bicortical manner. Two days later, the bird was fully weight-bearing on the leg. Radiographs performed 4 and 8 weeks after surgery showed good healing of the affected bone with an appropriate callus formation bridging the fracture line. Sixteen weeks after surgery, the patient was readmitted because of lameness exhibited while staying outside exposed to subzero (°C) temperatures. On the basis of this finding, heat conduction was postulated as the possible cause of lameness because it disappeared after implant removal. To the best our knowledge, this case represents the first report of a surgical repair of a tibiotarsal fracture with a locking plate in waterfowl.

Finite element analysis of the stability of AO/OTA 43-C1 type distal tibial fractures treated with distal tibia medial anatomic plate versus anterolateral anatomic plate.

BACKGROUND: The treatment of a pilon fracture type is possible from a medial, an anterolateral approach or both medial and lateral. The aim of study was compare the stability of two different plate fixation of a tibia pilon AO-43C1 type fractures. MATERIAL AND METHODS: In this study, three-dimensional finite element stress analysis was applied using isotropic materials and static linear analysis. Loading of 400 N force was applied to the model of a patient fixed in a standing position. In the model, first the fibula was treated by plating and then in one group the pilon fracture was treated by medial plating, and in the other by anterolateral plating. The displacement and stress values of the fragments of the fracture line were compared of the same points in each model. RESULTS: The magnitude of the displacement of fragments in the total displacement magnitudes of X, Y, Z axis were measured in the medial plate and anterolateral plate. The anterolateral plate results were similar to those of the medial plate and the displacement values in the Y axis were determined to be lower than in the medial plate. CONCLUSION: In AO 43 C1 distal tibia fractures, medial or anterolateral plates can be used, and the results of this study showed similar biomechanical stiffness in the two plates.

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.

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.

Mechanical Construct Characteristics Predisposing to Non-union After Locked Lateral Plating of Distal Femur Fractures.

OBJECTIVES: To identify discrete construct characteristics related to overall construct rigidity that may be independent predictors of nonunion after lateral locked plate (LLP) fixation of distal femur fractures. DESIGN: Retrospective case-control study. SETTING: Three level-1 urban trauma centers. PATIENTS/PARTICIPANTS: Two hundred and seventy-one supracondylar femoral fractures treated with LLP at 3 affiliated level 1 urban trauma centers between August 2004 and December 2010. METHODS: Nonunion was defined as a secondary procedure for poor healing. Construct variables included: (1) combined plate design and material variable, (2) Plate length, (3) # screws proximal to fracture, (4) total screw density (TSD), (5) proximal screw density (PSD), (6) presence of a screw crossing the main fracture, and (7) rigidity score multivariable analysis was performed using logistic regression to identify independent risk factors for nonunion. INTERVENTION: LLP fixation. MAIN OUTCOME MEASURE: Nonunion. RESULTS: Nonunion rate was 13.3% (n = 36). There was a significant association between plate design/material and nonunion with 41% of stainless constructs and 10% of titanium constructs resulting in a nonunion (P < 0.001). Rigidity scores reached significance (P = 0.001) with constructs resulting in a nonunion having higher scores. No significant univariate differences with respect to number of proximal screws, plate length, total screw density, or proximal screw density were observed between healed fractures and those with nonunion. Results of the multivariate analysis confirmed that the primary significant independent predictor of nonunion was plate design/material (odds ratio, 6.8; 95% CI, 2.9-16.1; P < 0.001). CONCLUSIONS: When treating distal femur fractures with LLP, combined plate design and material variable has a highly significant influence on the risk of nonunion independent of any other construct variable. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

[One-stage bone grafting combined with non-contact plate technique for treatment of post-traumatic femoral osteomyelitis and bone defects].

Eight patients with femoral osteomyelitis were admitted in Lanzhou General Hospital of PLA between July 2012 and July 2015. During the operation the femur was fixed with non-contact locking plate after thorough debridement. Iliac morselized cancellous bones without cortical bone were filled in the bone defect after debridement. The locking plates were placed in the lateral subcutaneous interface superficial to the vastus lateralis muscle. Drainage tubes were routinely placed postoperatively. The surgery was completed successfully in all patients, and the average operation time was (130±10) min (120-150 min). Intravenous antibiotics were administrated for 2 weeks and followed by 4 week-oral antibiotics after the operation in all 8 cases. Drainage tubes remained in situ about 8 days. All patients were followed up for 12-48 months, with an average of (19±7) months. Postoperative X-ray examination showed bone union in 7 cases with an average healing time of (16±5) weeks. One patient failed with relapsed infection, and was later treated with Ilizarov apparatus after secondary debridement. No plate and screw fracture, loose and fixation failure were observed in all 8 cases.

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.

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.

Corrective osteotomy for procurvatum deformity caused by distal femoral physeal fracture malunion stabilised with String-of-Pearls locking plates: results in two dogs and a review of the literature.

BACKGROUND: This report describes the treatment of severe procurvatum because of distal femoral physeal fracture malunion in two skeletally immature dogs. CASE REPORTS: Both dogs presented with severe right hindlimb lameness and markedly reduced stifle extension at less than 5 months of age. Severe distal femoral procurvatum and mild-to-moderate femoral shortening secondary to distal femoral physeal fracture malunion were evident on radiographs. The sagittal plane deformities were addressed with a caudal opening-wedge osteotomy in one dog and cranial closing wedge ostectomy in the other dog. String-of-Pearls locking plates were used to stabilise the osteotomies. Functional stifle extension range of motion and femoral length were improved post surgery in both dogs. Explantation of the plates was required in both dogs because of local soft tissue irritation. Both dogs had excellent outcomes based on subjective and objective measures (pressure sensitive walkway, force platform analysis) when assessed at skeletal maturity. CONCLUSIONS: Corrective osteotomy stabilised with String-of-Pearls locking plates is a viable treatment option for improving limb function in dogs with severe procurvatum deformities caused by distal femoral physeal fracture malunion.