The ideal treatment method regarding various defect sizes after local aggressive tumor resection is unknown. We investigated the biomechanical properties of metaphyseal defect filling regarding different defect sizes and fixation methods.

Ninety-one sheep tibias were divided into five groups as 21 tibias per four study groups and 7 tibias in the control group. Study groups were further divided into three subgroups according to 25%, 50% and 75% metaphyseal defect size. Control group tibias were left intact. In study group 1, a metaphyseal defect was created and no further process was applied. Metaphyseal defects were filled with cement without fixation in group 2. Cement filling and fixation with 2 screws were performed in group 3. In addition to cement filling, plate-screw fixation was performed in group 4. Axial loading test was applied to all tibias and the results were compared between study subgroups and control group.

Plate-screw fixation was found to have the best biomechanical properties in all defect sizes. Load to failure for screw fixation was found to be significantly decreased between 25% and 50% defect size (P<0.05). However, load to failure for isolated cement filling was not affected from defect size (p>0.05).

In conclusion, size of the defect predicts the fixation method in addition to filling with cement. Filling with cement in metaphyseal defects was found to be biomechanically insufficient. In addition to filling with cement, additional screw fixation in less than 25% defects and plate-screw fixation in more than 25% defects may decrease tibial plateau fracture or metaphyseal fracture risk after local aggressive tumor resection.

Introduction and Objective. Plating of geriatric distal femoral fractures with Locking Compression Plate Distal Femur (LCP–DF) often requires augmentation with a supplemental medial plate to achieve sufficient stability allowing early mobilization. However, medial vital structures may be impaired by supplemental medial plating using a straight plate. Therefore, a helically shaped medial plate may be used to avoid damage of these structures. Aim of the current study was to investigate the biomechanical competence of augmented LCP–DF plating using a supplemental straight versus helically shaped medial plate. Materials and Methods. Ten pairs of human cadaveric femora with poor bone quality were assigned pairwise for instrumentation using a lateral anatomical 15-hole LCP–DF combined with a medial 14-hole LCP, the latter being either straight or manually pre-contoured to a 90-degree helical shape. An unstable distal femoral fracture AO/OTA 33–A3 was simulated by means of osteotomies. All specimens were biomechanically tested under non-destructive quasi-static and destructive progressively increasing combined cyclic axial and torsional loading in internal rotation, with monitoring by means of optical motion tracking. Results. Initial axial stiffness and torsional stiffness in internal and external rotation for straight double plating (548.1 ± 134.2 N/mm, 2.69 ± 0.52 Nm/° and 2.69 ± 0.50 Nm/°) was significantly higher versus helical double plating (442.9 ± 133.7 N/mm, 2.07 ± 0.32 Nm/° and 2.16 ± 0.22 Nm/°), p≤0.04. Initial interfragmentary axial displacement and flexural rotation under 500 N static loading were significantly smaller for straight plating (0.11 ± 0.14 mm and 0.21 ± 0.10°) versus helical plating (0.31 ± 0.14 mm and 0.68 ± 0.16°), p<0.01. However, initial varus deformation under this loading remained not significantly different between the two fixation methods (straight: 0.57 ± 0.23°, helical: 0.75 ± 0.34°), p=0.08. During dynamic loading, within the course of the first 4000 cycles the movements of the distal fragment in flexion were significantly bigger for helical over straight plating (1.03 ± 0.33° versus 0.40 ± 0.20°), p<0.01. However, no significant differences were observed between the two fixation methods in terms of varus, internal rotation, axial and shear displacements at the fracture site, and number of cycles to failure. Conclusions. Augmented lateral plating of unstable distal femoral fractures with use of supplemental helically shaped medial plate was associated with more elastic bone-implant construct behavior under static and dynamic loading compared to straight double plating. Both fixation methods resulted in comparable number of cycles to failure. From a biomechanical perspective, the more elastic helical double plating may be considered as useful alternative to straight plating, potentially reducing stress risers at the distal bone-implant interface due to its ameliorated damping capacities

Helical plates potentially bypass the medial neurovascular structures of the thigh. Recently, two plate designs (90°- and 180°-helix) proved similar biomechanically behaviour compared to straight plates. Aims of this study were: (1) Feasibility of MIPO-technique with 90°- and 180°-helical plates on the femur, (2) Assessment of distances to adjacent anatomical structures at risk, (3) Comparison of these distances to using medial straight plates instead, (4) Correlation of measurements performed in anatomic dissection with CT-angiography. MIPO was performed in ten cadaveric femoral pairs using either a 90°-helical 14-hole-LCP (Group1) or a 180°-helical 15-hole-LCP-DF (Group2). CT angiography was used to evaluate the distances between the plates and the femoral arteries as well as the distances between the plates and the perforators. Subsequently, the specimens were dissected, and the distances were determined again manually. Finally, all helical plates were removed, and all measurements were repeated after application of straight medial plates (Group3). Closest overall distances between plates and femoral arteries were 15 mm (11 − 19 mm) in Group1, 22 mm (15 − 24 mm) in Group2 and 6 mm (1 − 8 mm) in Group3 with a significant difference between Group1 and Group3 (p < 0.001). Distances to the nearest perforators were 24 mm (15 − 32 mm) in Group1 and 2 mm (1 − 4 mm) in Group2. Measurement techniques (visual after surgery and CT-angiography) demonstrated a strong correlation of r. 2. = 0.972 (p < 0.01). MIPO with 90°- and 180°-helical plates is feasible and safe. Attention must be paid to the medial neurovascular structures with 90°-helical implants and to the proximal perforators with 180°-helical implants. Helical implants can avoid medial neurovascular structures compared to straight plates although care must be taken during their distal insertion. Measurements during anatomical dissection correlate with CT-angiography

Helical plates are preferably used for proximal humeral shaft fracture fixation and potentially avoid radial nerve irritation as compared to straight plates. Aims:(1) to investigate the safety of applying different long plate designs (straight, 45°-, 90°-helical and ALPS) in MIPO-technique to the humerus. (2) to assess and compare their distances to adjacent anatomical structures at risk. MIPO was performed in 16 human cadaveric humeri using either a straight plate (group1), a 45°-helical (group2), a 90°-helical (group3) or an ALPS (group4). Using CT-angiography, distances between brachial arteries and plates were evaluated. Following, all specimens were dissected, and distances to the axillary, radial and musculocutaneous nerve were evaluated. None of the specimens demonstrated injuries of the anatomical structures at risk after MIPO with all investigated plate designs. Closest overall distance (mm(range)) between each plate and the radial nerve was 1(1-3) in group1, 7(2-11) in group2, 14(7-25) in group3 and 6(3-8) in group4. It was significantly longer in group3 and significantly shorter in group1 as compared to all other groups, p<0.001. Closest overall distance (mm(range)) between each plate and the musculocutaneous nerve was 16(8-28) in group1, 11(7-18) in group2, 3(2-4) in group3 and 6(3-8) in group4. It was significantly longer in group1 and significantly shorter in group3 as compared to all other groups, p<0.001. Closest overall distance (mm(range)) between each plate and the brachial artery was 21(18-23) in group1, 7(6-7) in group2, 4(3-5) in group3 and 7(6-7) in group4. It was significantly longer in group1 and significantly shorter in group3 as compared to all other groups, p<0.021. MIPO with 45°- and 90°-helical plates as well as ALPS is safely feasible and showed a significant greater distance to the radial nerve compared to straight plates. However, distances remain low, and attention must be paid to the musculocutaneous nerve and the brachial artery when MIPO is used with ALPS, 45°- and 90°-helical implants. Anterior parts of the deltoid insertion will be detached using 90°-helical and ALPS implants in MIPO-technique

Surgical education of fracture fixation biomechanics relies mainly on simplified illustrations to distill the essence of the underlying principles. These mostly consist of textbook drawings or hands-on exercises during courses, both with unique advantages such as broad availability and haptics, respectively. Computer simulations are suited to bridge these two approaches; however, the validity of such simulations must be guaranteed to teach the correct aspects. Therefore, the aim of this study was to validate finite element (FE) simulations of bone-plate constructs to be used in surgical education in terms of fracture gap movement and implant surface strain. The validation procedure was conducted in a systematic and hierarchical manner with increasing complexity. First, the material properties of the isolated implant components were determined via four-point bending of the plate and three-point bending of the screw. Second, stiffness of the screw-plate interface was evaluated by means of cantilever bending to determine the properties of the locking mechanism. Third, implant surface strain and fracture gap motion were measured by testing various configurations of entire fixation constructs on artificial bone (Canevasit) in axial compression. The determined properties of the materials and interfaces assessed in these experiments were then implemented into FE models of entire fixation constructs with different fracture width and screw configurations. The FE-predicted implant surface strains and fracture gap motions were compared with the experimental results. The simulated results of the different construct configurations correlated strongly with the experimentally measured fracture gap motions (R. 2. >0.99) and plate surface strains (R. 2. >0.95). In a systematic approach, FE model validation was achieved successfully in terms of fracture gap motion and implant deformation, confirming trustworthiness for surgical education. These validated models are used in a novel online education tool OSapp (. https://osapp.ch/. ) to illustrate and explain the biomechanical principles of fracture fixations in an interactive manner

Aim. To investigate the effect of the eight plate position in sagittal plane on tibial slope in temporary epiphysiodesis technique applied to the proximal tibia and whether there is a rebound effect after removing the plate. Method. Forty New Zealand rabbits (6 weeks old) were divided into four groups. In all groups, two 1.3 mm mini plates and cortical screws implantation were placed on both medial and lateral side of the proximal epiphysis of the right tibia. In Group 1 and 3, the plates were placed on anterior of the proximal tibial anatomical axis in the sagittal plane, and placed posteriorly in Group 2 and 4. The left tibia was examined as control in all groups. Group 1 and Group 2 were sacrificed after four week-follow-up. In Group 3 and Group 4, the implants were removed four weeks after index surgery and the rabbits were followed four more weeks to investigate the rebound effect. The tibial slope was measured on lateral X-rays every two weeks. Both medial and lateral plateau slopes were evaluated on photos of the dissected tibia. Results. In Group 1, right MTPA (medial tibial plateau angle) and left MTPA, right LTPA (lateral tibial plateau angle) and left LTPA, and right 4wTPPA (the tibial proximal posterior angle at 4th week) and left 4wTPPA values were compared with each other. There was a significant difference in MTPA, LTPA, and 4wTPPA in Group 1 (p: 0.003, 0.006, 0.004). In Group 1, the medial and lateral slope significantly decreased after 4 weeks. There was no significant difference in MTPA, LTP and 4wTPPA measurements in Group 2 (p= 0.719, 0.306, 0.446, respectively). In Group 2, the slope did not change in four weeks. There was a significant difference in MTPA, LTPA, 4wTPPA, and 8wTPPA (tibial proximal posterior angle at 8th week) in Group 3 (p= 0.005, 0.002, <0.001, <0.001, respectively). In Group 3, the slope decreased at 4th week and remained stabile during the next four week-follow up and no rebound effect was observed. There was no significant difference in MTPA, LTPA, 4wTPPA, and 8wTPPA measurements in Group 4 (p= 0.791, 0.116, 0.232, 0.924), respectively. In group 4, slope did not change at 4th week of index surgery and no rebound effect was observed in the next four week-follow up. Conclusion. If eight plates were placed on anterior of lateral proximal tibia axis on both medial and lateral side, the tibial slope would reduce, and remain stabile after implant removal. Care should be taken to place the plates on the line of proximal tibial axis in sagittal plane in temporary epiphysiodesis technique performed due to angular knee deformities. Changing the slope due to plate placement can be used as a secondary gain for patients who will benefit from slope change, such as adolescent ACL surgery

Introduction. Pediatric femoral fracture including supracondylar and subtrochantric fracture constitutes 1.6% of all pediatrics fractures. 1. Elastic nails remain the standard treatment of choice in mid shaft transverse femoral fracture in children weighting less than 45kg. 2. But in subtrochantric and spiral femoral fracture, failure rate of TENS nails are quite high. 3. . Material and methods. We retrospectively reviewed 30 subtrochantric fracture in children (average age 9 years) treated with bridge plate by mini invasive approach. Result. All fracture united well in average 14 weeks. Single complication was 5mm limb lengthening due to fixation in traction on fracture table in one case. We strongly recommend bridge plate in complex femoral fracture in children

Transverse patella fractures are commonly encountered in trauma surgery, open reduction and internal fixation are considered the gold standard treatment modality that could permit early knee motion and immediate rehabilitation. Many fixation methods had been defined and compared to each other's in many clinical and biomechanical studies. The aim of this study was to assess the safety and stability of our novel anatomical patella plate and to compare its stability with tension band-wire technique. A total of 12 cadaveric preserved knees (six right and six left patellae) with close patellar size were chosen to form two groups of six samples. Each group received either plate or tension band-wiring fixation for an experimentally created patella fracture. Cyclic load of an average of 350 N was applied for all specimens and after accomplishing 50 cycles the displacements of all fracture edges were recorded. After completing 50 cycles in each group, the average fracture edges displacement measured in the plate group was 1.98 ± 0.299 mm, whereas the average fracture edges displacement measured in the tension band-wire group was 2.85 ± 0.768 mm (p = 0.016). In the operative treatment of displaced transverse patellar fractures, the strength of fixation obtained by titanium curved plates is highly stronger when compared to the fixation with a tension band-wire technique. Fixation with titanium curved plates provides satisfactory stability at the fracture site which allow withstanding the cyclic loads during the postoperative rehabilitation

Background. Plate fixation is one of several options available to surgeons for the management of pediatric femur fractures. Recent literature reports distal femoral valgus can be a complication following lateral plate fixation of femur fractures. We report on a case of extreme distal femoral valgus deformity and a lateral dislocation of the patella four years after having plate fixation of a left distal femoral fracture. Method. A single case was anonymised and retrospectively reviewed through examination of clinical and radiographic data. Results. A 15 year old male presented with 35 degree femoral valgus deformity, one inch leg length discrepancy, painful retained hardware and a lateral dislocation of the patella four years after undergoing lateral plate fixation of a left distal femur fracture. The fracture site healed after plate insertion, but later the patient reported worsening in alignment of lower extremity and complained of pain in the limb. Antero-posterior and lateral radiographs of the femur revealed 35 degrees of left distal femoral valgus. The previous femoral plate migrated proximally and was encased in bone. Due to plate migration, screws that were originally in the distal femoral metaphysis were protruding through the femoral shaft into soft tissues of the medial thigh. Successful treatment involved removal of prominent distal screws and use of a Taylor Spatial external fixator frame to correct the deformity. Lateral soft tissue release was performed to allow patellar relocation. At 12 weeks follow up leg alignment was restored, pain resolved and the patient was mobilising. Conclusion. Femoral valgus is a possible complication of lateral plate fixation in up to 30% of pediatric distal femur fractures. With this patient's combination of deformities as an example, we suggest early hardware removal after fracture union, preventing deformities developing. If plate removal is not chosen, then continued close monitoring of the patient is necessary until skeletal maturity. Level of Evidence. Type 4 (case report)

INTRODUCTION. Endochondral ossification in the growth plate is directly responsible for skeletal growth and its de novo bone-generating activity. Growth plates are vulnerable to disturbances that may lead to abnormal skeletal development. Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used analgesics but have been reported to impair endochondral ossification-driven fracture healing. Despite the general awareness that NSAIDs affect endochondral ossification, the consequences of NSAIDs on skeletal development are unknown. We hypothesise that the NSAID celecoxib leads to impaired growth plate development and consequently impairs skeletal development. METHODS. Healthy skeletally immature (5 weeks old) C57BL/6 mice were treated for ten weeks with celecoxib (daily oral administration 10 mg/kg) or placebo (water) (institutional approval 2013–094) (n=12 per group). At 15 weeks postnatally, total growth plate thickness, the thickness of specific growth plate zones, (immuno)histological analysis of extracellular matrix composition in the growth plate, cell number and cell size, longitudinal bone growth and bone micro-architecture by micro-CT were analysed. Inhibition of COX-2 activity was confirmed by determining PGE2 levels in plasma using an ELISA. RESULTS. No significant difference in total growth plate thickness or thickness of the resting zone, proliferative or hypertrophic zone was found between groups. Staining of growth plate extracellular matrix components revealed, however, a significantly higher proteoglycan content and less collagen type II staining in the proliferative zone. In the hypertrophic zone of the growth plates of celecoxib treated mice collagen type X was hardly detectable as compared to placebo mice. In addition, a significantly decreased cell number was observed in the hypertrophic zone of the growth plate and cells were significantly smaller in the celecoxib group. Micro-CT analysis of the subchondral bone region directly beneath the growth plate showed significantly higher bone density, bone volume density and trabecular thickness following celecoxib treatment. Despite the detected differences in extracellular matrix composition of the growth plate, no difference was found in the length of the tibia in celecoxib treated mice. DISCUSSION. In summary, there are no measurable differences found in murine skeletal formation as a result of treatment with celecoxib in this study. However, there are notable phenotypic features found in the maturation of the growth plate (hypertrophic zone and subchondral bone) as a result from the celecoxib treatment, of which the potential consequences we do not yet understand. SIGNIFICANCE. When follow-up actions from the use of celecoxib on the growing individual are found this may warrant re-evaluation for the use of celecoxib in these individuals

Objectives. The aim of this experimental study on New Zealand’s white rabbits was to investigate the transplantation of autogenous growth plate cells in order to treat the injured growth plate. They were assessed in terms of measurements of radiological tibial varus and histological characteristics. . Methods. An experimental model of plate growth medial partial resection of the tibia in 14 New Zealand white rabbits was created. During this surgical procedure the plate growth cells were collected and cultured. While the second surgery was being performed, the autologous cultured growth plate cells were grafted at the right tibia, whereas the left tibia was used as a control group. . Results. Histological examinations showed that the grafted right tibia presented the regular shape of the plate growth with hypertrophic maturation, chondrocyte columniation and endochondral calcification. Radiological study shows that the mean tibial deformity at the left angle was 20.29° (6.25 to 33) and 7.21° (5 to 10) in the right angle. . Conclusion. This study has demonstrated that grafting of autogenous cultured growth plate cells into a defect of the medial aspect of the proximal tibial physis can prevent bone bridge formation, growth arrest and the development of varus deformity. Cite this article: Bone Joint Res 2014;3:310–16

Basic engineering principles dictate that unplugged screw holes serve as sites of the concentration of stress and the initiation and growth of cracks (1,2). The idea of filling the holes were tested previously in the literature showing promising results (3). However there's either adverse results which might be a design mistake (4). The purpose of this study was to determine if the use of specially designed screw hole inserts in empty locking screw holes improves the strength and failure characteristics of locking plates. Forty two 7-hole locking LC/DCP plates were mounted on cylindric UHMW Polyethylene blocks with a 1-cm gap between blocks, simulating a fracture with comminution and bone loss. 21 plates had a screw hole insert placed in the center hole (centered over the simulated fracture), while 21 of the plates remained empty in the center hole. The plate–block constructs were placed in a mechanical testing machine and subjected to a series of loading conditions. The axial, bending and torsional stiffness and displacements needed for failure of each plate-block construct was calculated. The Statistical analysis was performed by Mann Whitney-U test for independent variables. All plates were then loaded to failure. There were significant difference in the axial load to failure (p=0.017), bending load to failure (p<0.01) and bending diplacements (p<0.01) of the test groups favoring the screw hole insert group as a higher mechanical strength. In conclusion the study demonstrates that the addition of the specially designed locking screw hole insert does significantly change the stength of the locking LC/DCP plates and might be suggested in the clinical application

Clavicular hook plates have been used over the last decade in the treatment of lateral clavicular fractures with good rates of union reported throughout the literature. Fewer studies have reported the functional outcome of these patients and some have reported potential soft tissue damage post plate removal. We aimed to review the functional outcomes alongside union rates in patients treated with hook plates for lateral clavicular fractures. In this retrospective case series, 21 patients with traumatic lateral third clavicular fractures were included. 15 had Neer type II fractures, 4 Neer type III fractures, 1 patient had a Neer type I fracture and 1 radiograph was not able to be classified. All patients were treated with clavicular hook plates at the same district general hospital by five experienced surgeons between March 2010 and February 2015 adhering to the same surgical protocol. All patients had standard physiotherapy and post operative follow up. Plates were removed when radiological union was achieved in all but one patient who had the plate removed before union was achieved due to prolonged non-union. Patients were followed up post plate removal and evaluated clinically using the Oxford Shoulder Score. Their post plate radiographs were assessed by an independent radiologist and bony union documented. 21 patients were included. Mean age was 40 (range 14–63) with a male:female ratio of 17:4. Mean follow up was 5 months post injury (1–26 months). The hook plate remained in situ for a mean time of 4.3 months (2–16 months). One patient developed a post-operative wound infection treated with antibiotics, 2 patients developed adhesive capsulitis, one patient had not achieved bony union prior to hook plate removal at 16 months, however did achieve union 2 months post plate removal, two patients required revision plating. All patients achieved bony union eventually with good alignment and no displacement of the acromioclavicular joint seen on the most recent post operative radiographs. Post plate removal Oxford Shoulder Scores indicated good shoulder function with a mean score of 41.5 (maximum score possible 48 and the range of scores for our cohort was 30–47). Our data would support the use of hook plates in the treatment of lateral clavicular fractures. All patients achieved union eventually with good alignment and this was reflected in the good functional outcome scores. This study is limited in its small cohort and short-term follow up. More research is required to examine the long term consequences of hook plate surgery in a larger patient population

Background. Volar locking plates have revolutionised the treatment for distal radius fractures. The DVR (Depuy) plate was one of the earliest locking plates which were used and they provided fixed angle fixation. Recently, newer volar locking plates, such as the Aptus (Medartis), have been introduced to the market that allow the placement of independent distal subchondral variable-angle locking screws to better achieve targeted fracture fixation. The aim of our study was to compare the outcomes of DVR and Aptus volar locking plates in the treatment of distal radial fractures. Methods. Details of patients who had undergone open reduction and internal fixation of distal radii from October 2007 to September 2010 were retrieved from theatre records. 60 patients who had undergone stabilisation of distal radius fractures with either DVR (n=30) or Aptus (n=30) plate were included in the study. Results. Mean age of patients undergoing fixation using DVR plate was 56.6 years (n=30) with 22 females and 8 males. Fractures in this group included 20 type 23-C, three type 23-B and seven type 23-A. The patients were followed up for an average of 5.5 months (2-16 months). 3 patients underwent revision of fixation due to malunion (n=1), non-union (n=1) and failure of fixation (n=1). Four patients had reduced movements even after intensive physiotherapy necessitating removal of plate. Mean age of patients undergoing Aptus volar locking plate fixation was 56.38 years (n=30) with 21 females and 9 males. There were 27 type 23-C, two type 23-B and one type 23-A fractures according to AO classification. The patients were followed up for an average of 4.1 months (2-11 months). 2 patients developed complex regional pain syndrome (CRPS) and 1 patient underwent removal of screws due to late penetration of screws into the joint. Conclusion. Complex and unstable fractures of the distal radius can be optimally managed with volar locking plates. Both systems are user friendly. Aptus plates provide an additional advantage of flexibility in implant positioning and enhanced intra-fragmentary fixation compared to the DVR plate. In our study Aptus plates had lower secondary surgical procedures compared to DVR plates

Different calcaneal plates with locked screws were compared in an experimental model of a calcaneal fracture. Four plate models were tested, three with uniaxially-locked screws (Synthes, Newdeal, Darco), and one with polyaxially-locked screws (90° ± 15°) (Rimbus). Synthetic calcanei were osteotomised to create a fracture model and then fixed with the plates and screws. Seven specimens for each plate model were subjected to cyclic loading (preload 20 N, 1000 cycles at 800 N, 0.75 mm/s), and load to failure (0.75 mm/s). During cyclic loading, the plate with polyaxially-locked screws (Rimbus) showed significantly lower displacement in the primary loading direction than the plates with uniaxially-locked screws (mean values of maximum displacement during cyclic loading: Rimbus, 3.13 mm (. sd. 0.68); Synthes, 3.46 mm (. sd. 1.25); Darco, 4.48 mm (. sd. 3.17); Newdeal, 5.02 mm (. sd. 3.79); one-way analysis of variance, p < 0.001). The increased stability of a plate with polyaxially-locked screws demonstrated during cyclic loading compared with plates with uniaxially-locked screws may be beneficial for clinical use

There is a growing trend towards using pre-clinical models of atrophic non-union. This study investigated different fixation devices, by comparing the mechanical stability at the fracture site of tibia bone fixed by either intramedullary nail, compression plate or external fixator. 40 tibias from adult male Wistar rats' cadavers were osteotomised at the mid-shaft and a gap of 1 mm was created and maintained at the fracture site to simulate criteria of atrophic non-union model. These were divided into five groups (n=8 in each): the first group was fixed with 20G intramedullary nail, the second group with 18G nail, the third group with 4-hole plate, the fourth group with 6-hole plate, and the fifth group with external fixator. Tibia was harvested by leg disarticulation from the knee and ankle joints, the soft tissues were carefully removed from the leg, and tibias were kept hydrated throughout the experiment. Each group was then subdivided into two subgroups for mechanical testing: one for axial loading (n=4) and one for 4-point bending (n=4). Statistical analysis was carried out by ANOVA with a fisher post-hoc comparison between groups. A p-value less than 0.05 was considered statistically significant. Axial load to failure data and stiffness data revealed that intramedullary nails are significantly stronger and stiffer than other devices, however there was no statistically significant difference axially between the nail thicknesses. In bending, load to failure revealed that 18G nails are significantly stronger than 20G. We concluded that 18G nail is superior to the other fixation devices, therefore it has been used for in-vivo experiments to create a novel model of atrophic non-union with stable fixation

Sex hormones play important roles in the regulation of the proliferation, maturation and death of chondrocytes in the epiphyseal growth plate. We have investigated the effects of male castration on the cell kinetics of chondrocytes as defined by the numbers of proliferating and dying cells. The growth plates of normal rabbits and animals castrated at eight weeks of age were obtained at 10, 15, 20 and 25 weeks of age. Our study suggested that castration led to an increase in apoptosis and a decrease in the proliferation of chondrocytes in the growth plate. In addition, the number of chondrocytes in the castrated rabbits was less than that of normal animals of the same age

We present a novel use for an adult proximal humeral locking plate. In our case an 18-year-old female with cerebral palsy sustained a peri-prosthetic fracture of a blade plate previously inserted for a femoral osteotomy. Treatment was revision using a long proximal humeral locking plate. She had a successful outcome. We present the history and operative management. The female had a history of quadriplegic cerebral palsy, asthma, diabetes mellitus and congenital heart disease. She had a gastrostomy tube for enteral feeding. She was on nutritional supplements, baclofen, Omeprazole and movicol. She is looked after by her parents and requires a wheelchair for mobility. She is unable to communicate. Surgical History: Right adductor tenotomy, aged 11. Femoral Derotation Osteotomy & Dega Acetabular Osteotomy, aged 13. Right distal hamstring and knee capsule release, aged 14. Admitted to A&E (aged 18); unwitnessed fall. Painful, swollen, deformed thigh with crepitus. Xrays demonstrated peri- prosthetic fracture below blade plate. No specific equipment available to revise. Decision made to use PHILOS (Synthes, UK). GA, antibiotics, supine on table. Lateral approach. Plate removed after excising overgrown bone. Reduced and held. 10hole PHILOS applied. Near anatomical reduction. Secure fixation with locking screws proximally away from blade plate defect. Blood loss 800ml. 5 days in hospital. Sequential fracture clinic review. Wound healed well. Fracture healed on Xray at 11 months and discharged. To our knowledge this is the first reported use of a PHILOS plate for this specific fracture. The complexity of this case and underlying neurological disorder deemed long blade plate revision unsuitable. Fracture rates after femoral derotation osteotomies rare. 5/157 and 1/58 in the two largest studies to date. Conservative measures were the main recommendation. We have demonstrated a straightforward method for revision fixation with an excellent outcome. It would be recommended as an alternative to other surgeons in this position

Background. Bothlimited-contact dynamic compression plate (LC-DCP) and locking compression plate (LCP) systems were designed to provide enhanced bone healing and to improve stability at fracture site. However, implant failure, delayed union, nonunion and instability are still frequently encountered complications. The purpose of this study was to determine the biomechanical characteristics of a novel persistent compression dynamic plate (PCDP) which provides a persistent compression to fracture edges, and to compare the biomechanical properties of such a novel plate with the commonly used LCP. Methods. The novel persistent compression dynamic plate (PCDP) system is composed of a body, an inner compression spring and a distal mobile component. The body (proximal part) contains an adjustable screw and the distal part of the dynamic system can slide inside the body through a special tube. 12 (saw bone) artificial femoral bones were used. Transverse distal shaft fracture was created in all the saw bones at the same level, 6 femurs were fixed using the novel PCDP, whereas the other 6 femurs were fixed using the well-known LCP. All samples had undergone a nondestructive repetitive different forces (axial compression, bending and torsion), to evaluate the biomechanical differences between the two plating systems. Results. Under axial load the mean stiffness value was 439,0 N/mm for the PCDP and 158,9 N/mm for the LCP. There was nosignificant difference in A-P (anteroposterior) ve P-A (posteroanterior) bending stiffness values between PCDP and LCP, P=0.37 and P=0.80 respectively. However LCP provided significantly stiffer fixation in medial and lateral bending tests than PCDP (P=0.037) and (P=0.016), respectively. But no significant difference was detected between the two plating system in the torsional stiffness P=0.15. Conclusion. These results do not show any significant biomechanical difference in the applied torsional and bending stresses between LCP and PCDP. However the remarkably increased persistent compression effect of the PCDP created a considerable stress on fracture edges which may accelerate bone healing. Level of Evidence. Level 5

Background. Surgical management of calcaneus fractures is demanding and has a high risk of wound complications. Traditionally these fractures are managed with splinting until swelling has subsided. We describe a novel protocol for the management of displaced intra-articular calcaneus fractures utilising a temporizing external fixator and staged conversion to plate fixation through a sinus tarsi approach. The goal of this technique is to allow for earlier treatment with open reduction and internal fixation, minimise the amount of manipulation required at the time of definitive fixation and reduce the wound complication rate seen with the extensile approach. Methods. The records of patients with displaced calcaneus fractures from 2010–2014 were retrospectively reviewed. A total of 10 patients with 12 calcaneus fractures were treated with this protocol. All patients underwent ankle-spanning medial external fixation within 48 hours of injury. Patients underwent conversion to open plate fixation through a sinus tarsi approach when skin turgor had returned to normal. Time to surgery, infection rate, wound complications, radiographic alignment, and time to radiographic union were recorded. Results. The average Bohler's angle improved from 13.2 (range −2 to 34) degrees preoperatively to 34.3 (range 26 to 42) degrees postoperatively. The average time from external fixation to conversion to internal fixation was 4.8 (range 3 to 7) days. There were no immediate post-surgical complications. The average time to weight bearing was 8.5 weeks. The average time to radiographic union was 9.5 (range 8 to 12) weeks. There were no infections or wound complications at the time of last follow-up. Conclusions. Early temporizing external fixation for the acute management of displaced calcaneus fractures is a safe and effective method to reduce and stabilise the foot and may decrease the time to definitive fixation. In our series there were no complications related to the use of the external fixator. Level of Evidence. IV Retrospective case series