Aims. The Chopart joint complex is a joint between the midfoot and hindfoot. The static and dynamic support system of the joint is critical for maintaining the medial longitudinal arch of the foot. Any dysfunction leads to progressive collapsing flatfoot deformity (PCFD). Often, the tibialis posterior is the primary cause; however, contrary views have also been expressed. The present investigation intends to explore the comprehensive anatomy of the support system of the Chopart joint complex to gain insight into the cause of PCFD. Methods. The study was conducted on 40 adult embalmed cadaveric lower limbs. Chopart joint complexes were dissected, and the structures supporting the joint inferiorly were observed and noted. Results. The articulating bones exhibit features like a cuboid shelf and navicular beak, which appear to offer inferior support to the joint. The expanse of the spring ligament complex is more medial than inferior, while the superomedial part is more extensive than the intermediate and inferoplantar parts. The spring ligament is reinforced by the tendons in the superomedial part (the main tendon of tibialis posterior), the inferomedial part (the plantar slip of tibialis posterior), and the master knot of Henry positioned just inferior to the gap between the inferomedial and inferoplantar bundles. Conclusion. This study highlights that the medial aspect of the talonavicular articulation has more extensive reinforcement in the form of superomedial part of spring ligament and tibialis posterior tendon. The findings are expected to prompt further research in weightbearing settings on the pathogenesis of flatfoot. Cite this article: Bone Jt Open 2024;5(4):335–342

Background. Lisfranc fracture dislocations are uncommon injuries, which frequently require surgical intervention. Currently, there is varying evidence on the diagnostic utility of plain radiographs (XR) and CT in identifying Lisfranc injuries and concomitant fractures. Our aim was to identify the utility of XR as compared to CT, with the nul hypothesis that there was no difference in fracture identification. Methods. A retrospective assessment of patients who had sustained a Lisfranc injury between 2013 and 2022 across two trauma centres within the United Kingdom who underwent surgery. Pre-operative XR and CT images were reviewed independently by 2 reviewers to identify the presence of associated fractures. Results. A total of 175 patients were included. Our assessment identified that XR images significantly under-diagnosed all metatarsal and midfoot fractures. The largest discrepancies between XR and CT in their rates of detection were in fractures of the cuboid (5.7% vs 28%, p<0.001), medial cuneiform (20% vs 51%, p=0.008), lateral cuneiform (4% vs 36%, p=0.113), second metatarsal (57% vs 82%, p<0.001), third metatarsal (37% vs 61%, p<0.001) and fourth metatarsal (26% vs 43%, p<0.001). As compared to CT, the sensitivity of XR was low. The lowest sensitivity for identification however was lateral foot injuries, specifically fractures of the lateral cuneiform (sensitivity 7.94%, specificity 97.3%), cuboid (sensitivity 18.37%, specificity 99.21%), fourth (sensitivity 46.7%, specificity 89.80%) and fifth metatarsal (sensitivity 45.00%, specificity 96.10%). Conclusion. From our analysis, we can determine that XR significantly under-diagnoses associated injuries in patient sustaining an unstable Lisfranc injury, with lateral foot injuries being the worst identified. We advised the use of CT imaging in all cases for appropriate surgical planning

Introduction. Charcot neuroarthropathy is a limb threatening condition and the optimal surgical strategy for limb salvage in gross foot deformity remains unclear. We present our experience of using fine wire frames to correct severe midfoot deformity, followed by internal beaming to maintain the correction. Materials and Methods. Nine patients underwent this treatment between 2020–2023. Initial deformity correction by Ilizarov or hexapod butt frame was followed by internal beaming with a mean follow up of 11 months. A retrospective analysis of radiographs and electronic records was performed. Meary's angle, calcaneal pitch, cuboid height, hindfoot midfoot angle and AP Meary's angle were compared throughout treatment. Complications, length of stay and the number of operations are also described. Results. Mean age was 53 years (range:40–59). Mean frame duration was 3.3 months before conversion to beaming. Prior frame-assisted deformity correction resulted in consistently improved radiological parameters. Varying degrees of subsequent collapse were universal, but 5 patients still regained mobility and a stable, plantargrade, ulcer-free foot. Complications were common, including hardware migration (N=6,66%), breakage (N=2,22%), loosening (N=3,33%), infection (N=4,44%), 1 amputation and an unscheduled reoperation rate of 55%. Mean cumulative length of stay was 42 days. Conclusions. Aggressive deformity correction and internal fixation for Charcot arthropathy requires strategic and individualised care plans. Complications are expected for each patient. Patients must understand this is a limb salvage scenario. This management strategy is resource heavy and requires timely interventions at each stage with a well-structured MDT delivering care. The departmental learning points are to be discussed

Aim. The aim of this paper is to analyse the cause of neuropathic diabetic foot ulcers and discuss their preventive measures. Methods. Review of patients with foot ulcers managed in our diabetic MDT clinics since Feb 2018 were analysed. Based on this observation and review of pertinent literature, following observations were made. Results. Forefoot. Progressive hindfoot equinus from contraction of gastroc-soleus-tendo-Achilles complex, with additional contraction of tibialis posterior and peroneal longus muscles and, progressive plantar flexed metatarsal heads secondary to claw toe deformity results in increased forefoot plantar pressures. In patients with insensate feet, this result in ulcer formation under the metatarsal heads from shear stress when walking. Callosity under the metatarsal heads is the earliest clinical sign. Most patients by this time have fixed tightness of the muscle groups as assessed by negative Silfverskiold test. Percutaneous tendo-Achilles lengthening (TAL) has shown to reduce the mid-forefoot plantar pressures by 32% and ulcer healing in 96% of patients within 10 weeks (± 4 weeks). Additional z-lengthening of peroneal longus and tibialis posterior tendons helped in patients with big-toe and 5. th. metatarsal head ulcers. Proximal metatarsal osteotomies further reduce the forefoot pressures to near normality. Midfoot. Midfoot ulcers are secondary to rocker-bottom deformity a consequence of Charcot neuroarthropathy (CN). Hindfoot equinus as described and relative osteopenia from neurally mediated increased blood flow (neurovascular theory) and repeated micro-trauma (neurotraumatic theory) result in failure of medial column osseo-ligamentous structures. As the disease progress to the lateral column, the cuboid height drops resulting in a progressive rocker bottom deformity. The skin under this deformity gradually breaks down to ulceration. In the pre-ulcerative stages of midfoot CN, TAL has shown to stabilise the disease progression and in some patents’ regression of the disease process was noted. The lump can excised electively and the foot accommodated in surgical shoes. Hindfoot. These develop commonly at the pressure areas and bony exostosis in non-ambulatory patients. In ambulatory patients, the most common cause are factors that result in over lengthening of tendo-Achilles such as after TAL, spontaneous tears, or tongue-type fractures. Conclusions. Early identification of factors that result in plantar skin callosity and treating the deforming forces prevent progression to ulceration. Total contact cast without treatment of these deforming forces results in progression of these callosities to ulceration while in the cast or soon after completion of cast treatment

The value of ultrasonography (US) was assessed for studying the position of the navicular and the cuboid in children with clubfeet (CF). In most studies on the management of CF, more than 50% of the patients have required surgical treatment for correcting foot deformities. In addition, repeat surgery is commonly needed for correction of residual foot deformities, especially persistent forefoot adduction usually due to medial displacement of the navicular and sometimes also the cuboid. These conditions have often been overlooked at the initial surgery. The authors examined 50 CF and 100 normal feet by US in children during the first year of life. With the transducer, the position of the navicular was studied along the medial border of the foot, and the position of the cuboid along the lateral border of the foot. The results indicated that 1) Severe medial displacement of the navicular towards the medial malleolus, which might not be possible to reveal by clinical examination, was commonly seen in children with CF and 2) severe medial displacement of the cuboid was seen considerably less frequently. Ultrasonography, using the most recent type of equipment, is a helpful tool when deciding if the navicular and the cuboid need to be re-aligned by open reduction in children with CF during the first year of life

In oncological resections there is a higher risk of infection around the foot and ankle. An infection here can be difficult to treat and easily lead to an amputation due to the limited amount of soft tissue coverage of the region. In three patients an infection developed after resection of a bone tumour in the foot and ankle. In the first case, female 34 years, an epitheloid hemangioepithelioma was excised from the anterior part of the calcaneus, cuboid and lateral os cuneiform. An iliac crest graft was initially used to fill the defect, but got infected. The antibiotic loaded bone cement spacer cured the infection and filled the dead space but was painful. A free vascularised fibula with skin-flap was used successfully to fill the defect and take away the pain. At three-year follow-up there is no pain and full weight bearing, with a nice hypertrophy of the graft. In the second case, a 14-year old girl, there was an Aneu-rismal Bone Cyst (ABC) of the distal tibia with a deep infection after ethibloc injection. The vacuum assisted closure cleaned the wound but a defect resulted. It was successfully filled with an ipsilateral free vascularised fibula with skin-flap. Follow-up shows full function and nice hypertrophy at 24 months. In the third case, male 65 years, a chondrosarcoma grade one (after biopsy) in the cuboid was curetted out. It proved grade two in the definitive histology and furthermore it got infected. The cuboid was excised and a cement spacer was placed. The soft tissues were insufficient to close it properly. A free vascularised fibula with skin-flap was used. The vascularity of the graft was insufficient and the skin-flap did not survive. A vacuum assisted closure was done. He can bear weight and has no pain. The fibula graft is shows some hypertrophy and a fistula persists for 18 months now. We conclude that vascularised free fibula with skinflap can successfully prevent amputation in case of infection in oncological resection of foot and ankle. The fibula reconstructs the bone defect and the skin-flap the soft tissue defect

Objective. The objective of this study was to evaluate the rotation and translation of each joint in the hindfoot and compare the load response in healthy feet with that in stage II posterior tibial tendon dysfunction (PTTD) flatfoot by analysing the reconstructive three-dimensional (3D) computed tomography (CT) image data during simulated weight-bearing. . Methods. CT scans of 15 healthy feet and 15 feet with stage II PTTD flatfoot were taken first in a non-weight-bearing condition, followed by a simulated full-body weight-bearing condition. The images of the hindfoot bones were reconstructed into 3D models. The ‘twice registration’ method in three planes was used to calculate the position of the talus relative to the calcaneus in the talocalcaneal joint, the navicular relative to the talus in talonavicular joint, and the cuboid relative to the calcaneus in the calcaneocuboid joint. Results. From non- to full-body-weight-bearing condition, the difference in the talus position relative to the calcaneus in the talocalcaneal joint was 0.6° more dorsiflexed (p = 0.032), 1.4° more everted (p = 0.026), 0.9 mm more anterior (p = 0.031) and 1.0 mm more proximal (p = 0.004) in stage II PTTD flatfoot compared with that in a healthy foot. The navicular position difference relative to the talus in the talonavicular joint was 3° more everted (p = 0.012), 1.3 mm more lateral (p = 0.024), 0.8 mm more anterior (p = 0.037) and 2.1 mm more proximal (p = 0.017). The cuboid position difference relative to the calcaneus in the calcaneocuboid joint did not change significantly in rotation and translation (all p ≥ 0.08). . Conclusion. Referring to a previous study regarding both the cadaveric foot and the live foot, joint instability occurred in the hindfoot in simulated weight-bearing condition in patients with stage II PTTD flatfoot. The method used in this study might be applied to clinical analysis of the aetiology and evolution of PTTD flatfoot, and may inform biomechanical analyses of the effects of foot surgery in the future. Cite this article: Bone Joint Res 2013;2:255–63

The detailed biomechanical mechanism of annulus fibrosus under abnormal loading is still ambiguous, especially at the micro and nano scales. This study aims to characterize the alterations of modulus at the nano scale of individual collagen fibrils in annulus fibrosus after in-situ immobilization, and the corresponding micro-biomechanics of annulus fibrosus. An immobilization model was used on the rat tail with an external fixation device. Twenty one fully grown 12-week-old male Sprague-Dawley rats were used in this study. The rats were assigned to one of three groups randomly. One group was selected to be the baseline control group with intact intervertebral discs (n=7). In the other two groups, the vertebrae were immobilized with an external fixation device that fixed four caudal vertebrae (C7-C10) for 4 and 8 weeks, respectively. Four K-wires were fixed in parallel using two aluminum alloy cuboids which do not compress or stretch the target discs. The immobilized discs were harvested and then stained with hematoxylin/eosin, scanned using atomic force microscopy to obtain the modulus at both nano and micro scales, and analyzed the gene expression with real-time quantitative polymerase chain reaction. Significance of differences between the study groups was obtained using a two-way analysis of variance (ANOVA) with Fisher's Partial Least-Squares Difference (PLSD) to analyze the combined influence of immobilization time and scanning region. Statistical significance was set at P≤0.05. Compared to the control group, the inner layer of annulus fibrosus presented significant disorder and hyperplasia after immobilization for 8 weeks, but not in the 4 week group. The fibrils in inner layer showed an alteration in elastic modulus from 91.38±20.19MPa in the intact annulus fibrosus to 110.64±15.58MPa (P<0.001) at the nano scale after immobilization for 8 weeks, while the corresponding modulus at the micro scale also underwent a change from 0.33±0.04MPa to 0.47±0.04MPa (P<0.001). The upregulation of collagen II from 1±0.03 in control to 1.22±0.03 in 8w group (P = 0.003) was induced after immobilization, while other genes expression showed no significant alteration after immobilization for both 4 and 8 weeks compared to the control group (P>0.05). The biomechanical properties at both nano and micro scales altered in different degrees between inner and outer layers in annulus fibrosus after immobilization for different times. Meanwhile, the fibril arrangement disorder and the upregulation of collagen II in annulus fibrosus were observed using hematoxylin/eosin staining and real-time RT-PCR, respectively. These results indicate that immobilization not only influenced the individual collagen fibril at the nano scale, but also suggested alterations of micro-biomechanics and cell response. This work provides a better understanding of IVD degeneration after immobilization and benefits to the clinical treatment related to disc immobilization

Introduction: The unique architecture of the tarsometa-tarsal joints gives rise to a complex articulation between the midfoot and forefoot. The Lisfranc injury has a classic pattern leaving its telltale signs in an arch pattern starting at the medial cuneiform, continuing through the second, third and fourth tarsometatarsal regions and finally may end as a fracture of the cuboid. However, various other patterns and classifications of Lisfranc fracture dislocation have been recorded in medical literature. Aim: To highlight the hitherto undescribed arch patterns of Lisfranc injuries. Methodology: 8 patients with atypical Lisfranc injuries were studied prospectively. Arch patterns: In 2 patients the arch started at the medial aspect of the ankle with injury to the medial malleolus or the deltoid ligament, passed through the tarsometatarsal region and ended at the cuboid. In one patient the arch started at the tarsometatarsal joints and ended at the lateral malleolus and in another patient the lateral end point resulted in tear of the calcaneofibular ligament. One patient had the medial starting point at the Lisfranc ligament but the arch of injuries went through the forefoot fracturing the midshaft of the 2nd, 3rd and 4th metatarsal shafts without injuring the tarsometatarsal region, thus forming an arch pattern much more distal than usual. Six of the 8 patients had operative management. On follow up, in terms of activities of daily living, 75% had excellent function of the foot. It is not the aim of this paper to highlight the management of these injuries. Conclusion: In the process of listing the telltale signs of a Lisfranc injury it is mandatory to bear in mind that the arch of injuries may extend to as proximal as the ankle joint or as distal as the forefoot and this will enable us to define the entire spectrum of the Lisfranc injury, however atypical it may be

Implant infection is an increasing problem in orthopedic surgery, especially due to progressive antibiotic resistance and an aging population with rising numbers of implantations. As a consequence, new strategies for infection prevention are necessary. In the previous study it was hypothesized that laser-structured implant surfaces favor cellular adhesion while hindering bacterial ongrowth and therewith contribute to reduce implant infections. Cuboid titanium implants (0.8 × 0.8 × 12 mm. 3. , n=34) were used. Seventeen were laser-structured by ultra-short pulsed laser ablation to create a spike structure; the others were polished and served as controls. In general anesthesia, implants were inserted in rat tibiae and infected with a S. aureus suspension. During a 21 day postoperative follow-up, daily clinical control was performed. Radiographs were taken at day 14 and day 21. After euthanasia, bacterial load and biofilm formation on the implant surface was evaluated semi quantitatively by confocal laser scanning microscopy and computational acquisition of bacteria and cells by Imaris®-software. Additionally, histology of the surrounding bone was performed. Clinically, no differences were observed between the groups. However, contrary to our hypothesis, bacterial load was increased in the laser-structured implant group although cellular adhesion was even more pronounced. Radiographical and histological evaluations showed increased bone alterations in the group with laser-structured implants compared to the control group. These findings did not confirm prior in vitro studies, where a reduction of bacterial load was found for similar surfaces and demonstrate the necessity of in vivo trials prior to the clinical use of new materials

Aims

To systematically review the efficacy of split tendon transfer surgery on gait-related outcomes for children and adolescents with cerebral palsy (CP) and spastic equinovarus foot deformity.

To date there has been no material for endoprosthetics providing excellent resistance to abrasion and corrosion combined with great tensile strength, fracture toughness, and bending strength, as well as adequate biocompatibility. Carbon-fiber-reinforced silicon carbide (C/SiC, C/C-SiC or C/SiSiC) is as a ceramic compound a potentially novel biomaterial offering higher ductility and durability than comparable oxide ceramics. Aim of this investigation was to test the suitability of C/SiC ceramics as a new material for bearing couples in endoprosthetics. One essential quality that any new material must possess is biocompatibility. For this project the in-vitro biocompatibility was investigated by using cuboid like scaffolds made of CMC. To determine whether the material is suited as a lubricant partner in endoprosthetics, we measured its abrasion coefficient and wear tolerance against various antibodies. The C/SiC samples tested were produced via the Liquid Silicon Infiltration (LSI) of pyrolized porous fiber preforms made by warm-flow pressing free-flowing granulates on a hydraulic downstroking press with a heated die of the type HPS-S, 1000 kN. After preparation of the composites, the tribological characteristics are determined. Flexural strength was determined at room temperature according to DIN685-3 with an universal testing machine Z100 and the Young”s -modulus was carried out via resonant frequency-damping analysis RFDA. The samples”surface as well as cell adhesion and cell morphology were assessed via ESEM. The human osteoblast-like cell line MG-63 and human ostoeblast were used for cel culture ecperiments (WST, Live/dead, Cytotoxicity, cell morphology). Based on the raw data the mean value and the standard deviation were calculated. The Mann-Whitney-U-Test was used to evaluate the differences between experiment and control samples. The flexural strength at room temperature is approx. 180 MPa, while the elongation at break is about 0.13%. The Young”s modulus is detected between 120 and 150 GPa. The density lies between 2.5 and 3.0 g/cm. 3. We noted a friction coefficient µ between 0.31. The cell lines exhibited no morphological alterations, and adhered well to the C/SiC samples. Vitality was not impaired by contact with the ceramic composite. Cell growth was observed evenly distributed over a 21-day period. In the future, investigators aiming to apply this composite in endoprosthetics will have to focus on its efficacy in conjunction with sudden, strong demands, and long-term performance in bodily fluids within joint simulators, etc. In conclusion: C/SiC can definitely be considered a new material with genuine potential for use in endoprosthetics

Aims

Highly cross-linked polyethylene (HXLPE) greatly reduces wear in total hip arthroplasty, compared to conventional polyethylene (CPE). Cross-linking is commonly achieved by irradiation. This study aimed to compare the degree of cross-linking and in vitro wear rates across a cohort of retrieved and unused polyethylene cups/liners from various brands.

The increase in revision joint replacement surgery and fractures of bone around orthopaedic implants may be partly addressed by keeping bone healthy around orthopaedic implants by inserting implants with mechanical properties closer to the patient's bone properties. We do not currently have an accurate way of calculating a patient's bone mechanical properties. We are therefore investigating whether microindentation can accurately calculate bone stiffness. We received ethical approval to retrieve femoral heads and necks from patients undergoing hip replacement surgery for research. Cortical bone from the medial calcar region of the femoral neck was cut into 3×3×6mm cuboid specimens. Micro-indentation testing was performed in the direction of loading of the bone using a MicroMaterials indenter. The samples were kept hydrated and were not fixed or polished. From the unloading curve after indentation, the elastic modulus was calculated, using the Oliver- Pharr method. To assess which microindentation machine settings most precisely calculate the elastic modulus we varied the loading and unloading rates, load and indenter tip shape. The most precise results were obtained by using a spherical indenter tip (rather than Berkovich tip), high load (10N), a loading rate of 100 mN/s and unloading rate of 300 mN/s with a pause of 60 seconds at maximum load and multiple load cycles with constant loads. Using these settings the mean elastic modulus over 12 cycles of testing was 13.0 GPa (+/- 2.47). By using a spherical indenter tip and fast unloading it was possible to get precise apparent modulus values. By unloading as fast as possible the effects of bone viscoelastic properties are minimised. By using a spherical indenter tip, plastic deformation at the tip is minimised (compared to the Berkovich tip). We are performing further standard compression tests on the samples to verify the accuracy of the indentation tests

Clubfoot is medically defined as luxatio pedis sub talo. The process of dislocation mostly caused by muscular imbalance results in bony deformities and soft tissue contractures, which in the majority of cases – even after meticulous conservative treatment – have to be corrected by surgery. In children before school age, surgical corrections should always address the main pathology. To achieve normal alignment of the fore and hindfoot, a complete reduction of the talus within the acetabulum pedis has to be done by soft tissue release. Analysing the pathomorphology, a clubfoot is characterised by equinus, varus, forefoot adduction, and horizontal subtalar medial rotation. Regarding bony deformation, the medial side of the talus is narrowed by the navicular, the medial malleolus, and the fibrocartilage between. Growth expansion is limited on the medial side and there is more growth expansion on the lateral convex side, leading to external rotation of its body (~ 10-25°) and internal inclination of the neck (~30-50°). The calcaneus is internally rotated 20-30°. Regarding joint dislocation, there is a displacement of the navicular medially and plantarward towards the medial malleolus. The cuboid bone usually follows the position of the navicular and dislocates gradually to the medial side. Soft tissue contractures are located medially (Lacinate Lig., M. Add. hallucis, Spring Lig., talo navicular Lig., Master knot of Henry) and posterior (lat. fibulo calc. Lig, post. capsule of the ankle joint). There is also a shortening of muscles e.g. short plantar flexors, M. tib. post., M. flex. hall. longus., M. flex. digit. comm., M. tib. ant. The method of treatment depends on the severity of a clubfoot, the preoperatively achieved results of conservative treatment, and how extensive a subtalar release has to be performed. If the navicular can be reduced conservatively, a posterolateral surgical approach is indicated. A transversal incision is performed starting laterally at the calcaneal cuboid joint and ending medially below the medial malleolus. A dorso lateral release of the subtalar joint, Tendo Achilles lengthening, and dorsal release of the ankle joint is performed. At the age of three to six months, it is possible to correct subtalar malalignment to move the calcaneus away from the fib. Malleolus by external rotation in relation to the talus (Mini Cincinnati technique). If the talonavicular and the calcaneo-cuboid joint are dislocated, a complete subtalar release has to be done in order to reduce the talo-navicular, calcaneo-cuboid and talo-calcaneal joint. To avoid overcorrection, the talo calcaneal interosseous lig. should be kept intact whenever possible (Mc Kay-Simons procedure). This type of surgery should not be performed before the age of six months. The subtalar release technique described by McKay was introduced in our hospital in 1983. Since then, 362 clubfeet have been treated by the above-mentioned techniques: 249 by the Mini Cincinnati (Group 1) and 113 by the McKay-Simons procedure (Group 2). Age at the time of surgery ranged from 2 to 12 months in Group 1 and 5 to 52 months in Group 2. In Group 1, the results were excellent in 42%, and good (residual forefoot adduction) in 49%. A second surgical intervention had to be done in only 9%. Regarding shape and appearance of the foot in Group 2, results were excellent in 46%, good in 38% and insufficient in 16% (overcorrection 3%, relapse 13 %). Concerning functional outcome, the feet of Group 2 presented much more stiffness than those of Group 1, which was also found pre-operatively. The treatment of clubfoot is still a matter of controversy because of different severity of deformity and different treatment philosophies. According to our experience, the McKay-Simons procedure has proved to be ideal for simultaneous correction of various components of the deformity from one single approach. In particular, correction of subtalar horizontal rotational deformity in the subtalar joint can be easily performed. Based on the survey, the danger of damaging nerves, blood vessels, tendons and joint cartilages can be kept to a minimum by using the Cincinnati approach. In the majority of cases, the foot appears normal, moves without pain, and is flexible enough to enable the child to walk on his toes or heels and to participate in sportactivities. Limitation of mobility is nevertheless the main problem of all extensive soft tissue procedures in clubfoot surgery, and it is not known at this time if this will cause subtalar osteoarthritis in early adulthood. Complete subtalar release develops less osteonecrosis, fewer changes in the navicular, and less cavus and adductus than the use of other surgical techniques. Overcorrection and poor functional results were seen in patients less than six months old at the time of surgery. We recommend that a complete subtalar release be delayed until the child is aged 6 to 12 months. Treatment should ideally be completed by the time the child is ready to walk

Aims

This study aimed to establish the optimal fixation methods for calcaneal tuberosity avulsion fractures with different fragment thicknesses in a porcine model.

We present a case of a 14 year old who sustained an isolated injury to her foot while horse riding. X-rays demonstrated a medial and plantar dislocation at the level of the talo-navicular and calcaneo-cuboid joint, with associated fractures of the cuboid and navicular. This was treated initially with open reduction and fixation with kirschner wires as the injury was grossly unstable and reduction difficult to maintain with casting alone. CT scan was then performed prior which confirmed satisfactory reduction of the dislocation and fixation with the k wires so these were left in situ and the navicular fracture reduced and fixed with a barouk screw. The Chopart joint was first described by French surgeon Francois Chopart as the talo-navicular and calcaneo-cuboid joints were a practical level for amputation. Injury here is a rare but missed in 40% at presentation. Pure dislocation occurs in 10–25% with most having concomitant fractures. The Chopart joint has critical role in balance and stability in normal gait. Early recognition allows prompt reduction and fixation of these injuries which has been associated with a better outcome. However these are severe injuries and patients should be counselled on potential long term functional impairment even with optimal management

Introduction. The increase in revision joint replacement surgery and fractures of bone around orthopaedic implants may be partly addressed by keeping bone healthy around orthopaedic implants by inserting implants with mechanical properties closer to the patient's bone properties. We do not currently have an accurate way of calculating a patient's bone mechanical properties. We therefore posed a simple question: can data derived from a micro-indenter be used to calculate bone stiffness?. Methods. We received ethical approval to retrieve femoral heads and necks from patients undergoing hip replacement surgery for research. Cortical bone from the medial calcar region of the femoral neck was cut into 3×3×6mm cuboid specimens using a diamond wafering blade. Micro-indentation testing was performed in the direction of loading of the bone using a MicroMaterials (MicroMaterials, UK) indenter, using the high load micro-indentation stage (see Figure 1). To simulate in vivo testing, the samples were kept hydrated and were not fixed or polished. From the unloading curve after indentation, the elastic modulus was calculated, using the Oliver-Pharr method using the indentation machine software. To assess which microindentation machine settings most precisely calculate the elastic modulus we varied the loading and unloading rates, load and indenter tip shape (diamond Berkovich tip, 1mm diameter Zirconia spherical tip and 1.5mm diameter ruby spherical tip). Following this, for 11 patients' bone, we performed compression testing of the same samples after they were indented with the 1.5mm diameter ruby spherical tip to assess if there was a correlation between indentation values of apparent elastic modulus and apparent modulus values calculated by compression testing (see Figure 2). Platens compression testing was performed using an Instron 5565 (Instron, USA) materials testing machine. Bluehill compliance correction software (Instron, USA) was used to correct for machine compliance. The strain rate was set at 0.03mm/s. The apparent elastic modulus was calculated from the slope of the elastic region of the stress-strain graph. The correlation between values of apparent modulus from compression testing and indentation were analyzed using IBM SPSS Statistics 22. Results. The most precise results were obtained using a spherical indenter tip (1.5 mm diameter ruby ball), rather than a sharp Berkovich tip, high load (10N), a loading rate of 100 mN/s and unloading rate of 300 mN/s with a pause of 60 seconds at maximum load. We also used multiple load cycles with a peak load of 10N (see Figure 3). Using these optimal settings we calculated the mean elastic modulus over 10 cycles of testing with six indents on one sample to be 11.8 GPa (+/− 1.01). There was a moderate correlation between indentation and compression values of apparent modulus (r=0.62, n=11, p=0.04). Discussion. By using a spherical indenter tip and fast unloading it was possible to get precise apparent modulus values. The apparent modulus derived from micro-indentation, correlated moderately with that derived from direct compression testing. This early data suggests that microindentation may become a clinically relevant test of bone quality in real time

Introduction: The sural nerve is commonly encountered in many operations on the lateral part of the foot and ankle, such as fixation of distal fibula, 5th metatarsal and calcaneal fractures, and fusion of the subtalar or calcaneo-cuboid joints. However there is no consensus and quantitative description of the branches of sural nerve distal to the ankle in the reviewed literature. This study aims to describe these branches and quantify their relations. Methods: The distal course of the sural nerve was dissected in 30 embalmed cadaveric limbs. Results: A fibular branch was found in close proximity to the tip of the distal fibula in 63% of specimens. A dorsal branch at the level of the cuboid was found in 80% of specimens, however, its point of departure from the main nerve varied considerably. More distally a series of plantar branches of varying number, and at varying distances to each other was found. These branches were then described in relation to the following bony landmarks: the tip of the distal fibula, the calcaneo-cuboid joint, the tuberosity of the base the 5th metatarsal, the shaft of the metatarsal and the 5th metatarso-phalangeal joint. The distances between these landmarks were quantified using digital analysis. Conclusion: The sural nerve has a number of previously undescribed but potentially important branches distal to lateral malleolus in the foot. Identifying these branches during surgery with relation to the various bony structures should minimise the risk of nerve injury

Sledging related minor and major injuries represent a significant workload at ski-area medical centers across the world. Although safety rules exist, they are seldom obeyed or enforced. We set out to determine the incidence of sledging related injuries, identifying trends and causative factors at a busy New Zealand Ski resort. All sledging related injuries presenting during a 70-day period were prospectively reviewed. Patient demographics, mechanism, diagnosis, and treatment were recorded. Sixty patients were identified, mean age 10 years, range 4-30 years. Injuries comprised; collisions with sledgers (21), collision with wall (14) and falling from sledge (14). Site of injury included head (36), lower limb (18), spine (9), upper limb (7), and abdomen (2). Fractures included; femur (1), tibia (1), fibula (1), ankle (2), cuboid (1), clavicle (2), scaphoid (1). One 9-year-old patient sustained a serious intracranial haemorrhage, with subsequent permanent neurological sequelae. Sledging related injuries are mostly minor, however significant major injuries do occur requiring intervention at a secondary center. The potential for serious morbidity is evident. Recommendations supporting safety improvement measures does exist, however most were not implemented by the study cohort examined. The use of basic cycling helmets would seem an appropriate minimum level of protection, and greater sledging safety awareness should be encouraged