Weight-bearing is a known stimulus for bone remodelling and a reduction in weight-bearing is associated with reduced bone mineral density (BMD) in affected limbs post lower limb fracture. This study investigated short and long-term precision of a method for measuring relative left/right weight-bearing using two sets of identical calibrated scales. The effect of imbalance on BMD at the hip and on lower limb lean tissue mass (LLTM) was also assessed. 46 postmenopausal women, with no history of leg or ankle fracture, were measured three times whilst standing astride two scales (Seca, Germany). 34 of the participants were re-measured after 6 months by the same method. Bilateral hip and total body dual x-ray absorptiometry measurements were performed using a GE Lunar Prodigy (Bedford, MA). Precision errors in weight-bearing measures were calculated using the root mean square coefficient of variation (RMSCV%). The correlations at the first visit between left/right differences in weight-bearing and differences in BMD and LLTM were calculated. The short-term RMSCV% for left and right weights were 4.20% and 4.25% respectively and the long-term RMSCV% were 6.91% and 6.90%. Differences in left/right weight-bearing ranged from 0 to 24% (SD 8.63%) at visit 1 and 0 to 30% (SD 10.71%) at visit 2. Using data from visit 1, the relationship between hip BMD differences and left/right weight-bearing differences were investigated, with no significant correlations found. However, a weak, but statistically significant correlation of r=0.35 (p=0.02) was found for differences in LLTM and left/right weight-bearing differences. In conclusion, left/right weight-bearing measured using two scales is a precise method for evaluating differences in weight-bearing in the short and long-term. Differences in left/right weight-bearing in this population varied by up to 30%. Participants showed a high degree of consistency in their long-term balance in a natural standing posture. Inequalities in left/right weight-bearing did not correlate significantly with BMD at the hip, but demonstrated a weak but statistically significant correlation with lean tissue mass

Abstract. Objectives. This study aims to evaluate the functional outcomes of early weight-bearing in a functional orthosis for conservatively managed, complete AT ruptures. Also we tried to evaluate the patient reported outcome with this form of treatment. Design. In this prospective study, we have analysed data from 41 patients with ultrasound diagnosed compete AT ruptures, with a gap of less than 5 cm. Every patient was treated in a functional weight-bearing orthosis (VACOped®) for 8 weeks with early weight-bearing following a specific treatment protocol, followed by rehabilitation with a trained physiotherapist. Methods. Patients were followed up with foot and ankle trained physiotherapist for at least 1 year post-injury. At final follow up, the followings were measured: calf girth, single-leg heel raise height and repetitions. Furthermore, ATRS score and a patient feedback were taken on this final visit. Result. The mean ATRS score was 82.1, with a re-rupture rate of only 2% as compared to 5% in normal orthosis. The average calf bulk difference was 1.6 cm, the average heel raise height difference was 1.8cm and a heel raise repetition difference of 6. There was a statistically significant correlation between ATRS score and calf muscle girth (p=0.02). However, there was no significant correlation between ATRS and heel raise height or heel raise repetitions. Conclusion. Early weight-bearing in a functional orthosis provides excellent functional outcomes for conservatively managed, complete AT ruptures, and is associated with very low re-rupture rates. A multidisciplinary approach with a guided rehabilitation programme is essential for optimising functional outcome

In a consecutive retrospective analysis of 190 patients treated with the Masquelet technique at the BG Klinikum Hamburg from January 2012 to January 2022, defect-specific features such as the extent and morphology of the defect were recorded, and their influence on the time to reach full weight-bearing of the affected limb was investigated. A total of 217 defects were treated in 190 patients using the Masquelet technique. 70% of all defects were located in the tibia, followed by 22% in the femur and only about 7% in the upper extremity. The average length of all defects was 58 mm (+/−31 mm), with the largest defect measuring 180 mm and the smallest measuring 20 mm. 89% of the patients achieved full weight-bearing at the end of therapy. The average time from initiation of therapy to reaching safe full weight-bearing was 589 days. There was a significant correlation between defect length and time to reach full weight-bearing (p = 0.0134). These results could serve as a basis for creating a score for prognostics and evaluation of bone healing after treatment with the Masquelet technique. Additionally, the results could help guide indications for secondary stabilization using internal fixation

Introduction and Objective. Postoperative management regimes vary following open reduction and internal fixation of unstable ankle fractures. There is an evolving understanding that poorer outcomes could be associated with non-weight bearing protocols and immobilisation. Traditional non-weight bearing cast immobilisation may prevent loss of fixation, and this practice continues in many centres. The aim of this systematic review and meta-analysis is to compare the complication rate and functional outcomes of early weight-bearing (EWB) versus late weight-bearing (LWB) following open reduction and internal fixation of ankle fractures. Materials and Methods. We performed a systematic review with a meta-analysis of controlled trials and comparative cohort studies. MEDLINE (via PubMed), Embase and the Cochrane Library electronic databases were searched inclusive of all date up to the search time. We included all studies that investigated the effect of weight-bearing following adults ankle fracture fixation by any means. All ankle fracture types, including isolated lateral malleolus fractures, isolated medial malleolus fractures, bi-malleolar fractures, tri-malleolar fractures and Syndesmosis injuries, were included. All weight-bearing protocols were considered in this review, i.e. immediate weight-bearing (IMW) within 24 hours of surgery, early weight-bearing (EWB) within three weeks of surgery, non-weight-bearing for 4 to 6 weeks from the surgery date (or late weight-bearing LWB). Studies that investigated mobilisation but not weight-bearing, non-English language publications and tibial Plafond fractures were excluded from this systematic review. We assessed the risk of bias using ROB 2 tools for randomised controlled trials and ROBINS-1 for cohort studies. Data extraction was performed using Covidence online software and meta-analysis by using RevMan 5.3. Results. After full-text review, fourteen studies (871 patients with a mean age ranged from 35 to 57 years) were deemed eligible for this systematic review; ten randomised controlled trials and four comparative cohort studies. Most of the included studies were rated as having some concern with regard to the risk of bias. There is no important difference in the infection rate between protected EWB and LWB groups (696 patients in 12 studies). The risk ratio (RR) is 1.30, [95% CI 0.74 to 2.30], I. 2. = 0%, P = 0.36). Other complications were rare. The Olerud-Molander Ankle Score (OMAS) was the widely used patient-reported outcome measure after ankle fracture fixation among the studies. The result of the six weeks OMAS analysis (three RCTs) was markedly in favour of the early weight-bearing group (MD = 10.08 [95% CI 5.13 to 15.02], I. 2. = 0%P = <0.0001). Conclusions. The risk of postoperative complications is an essential factor when considering EWB. We found that the overall incidence of surgical site infection was 6%. When comparing the two groups, the incidence was 5.2% and 6.8% for the LWB and EWB groups. This difference is not clinically important. On the other hand, significantly better early functional outcome scores were detected in the EWB group. These results are not without limitations. Protected early weight-bearing following open reduction and internal fixation of ankle fractures is potentially safe and improve short-term functional outcome. Further good-quality randomised controlled trials would be needed before we could draw a more precise conclusion

Abstract. In aged trauma patients the basic prerequisite is early mobilization and full weight-bearing, as immobilization can trigger various complications such as pressure ulcers, pneumonia, urinary tract infections and others. Mortality of elderly patients increases significantly in fracture patients with partial weight-bearing compared to populations with total weight-bearing. Besides the limited physical strength in these patients, partial-weight bearing is however frequently used for the aftercare of hip fracture patients. Therefore, the present study aims to evaluate mobility of aged hip fracture patients with regards to weight-bearing and postoperative mobility. Methods. An insole mobile force sensor was used to measure the post-operative weight-bearing by assessing the compressive forces between foot and shoe. Only patients (n=15) that suffered a trochanteric fracture >75 years of age were included and compared to a study group of patients (n=18) with fractures of the lower limb <40 years of age. Patients with cognitive disorders such as delirium and other diseases limiting the realization of partial weight-bearing were excluded. Both groups were instructed to maintain partial weight bearing of the affected limb following surgery. Following five days of training by our department of physiotherapy, the patients were requested to perform a gait analysis with the insole mobile force sensor. During gait analysis the maximum load was measured (kg) and the time over which the partial load could be maintained was determined. Results. None of the aged patients in the test group could meet the partial load at all times. 73.33% of patients (11 out of 15) exceeded the specified load by more than twice (> 40 kg). In the control group, 55.56% (10 of 18) of the patients were able to meet the partial load. A further 22.22% of the young patients (4 out of 18) were able to exceed only slightly (<120%, <24 kg). It was also shown that only 11.11% (2 of 18) put more than double of the allowed weight (> 40 kg) on the affected leg in the younger group. Only one of the aged patients was able to exceed the pre-determined weight-bearing restrictions for less than 10% of the measured time. In comparison, significantly more patients in the control group (88,89%; 16 of 18; p<0,05) were able to maintain the partial load for more than 90.0% of the time of gait analysis. Conclusion. Elderly patients seem to be unable to follow partial weight-bearing restrictions as proven in the present trial. As early mobilization of geriatric trauma patients is an important element for a successful rehabilitation, the relict of postoperative partial weight-bearing in these patients should be abandoned. Thus, the surgical therapy should allow immediate full weight bearing following surgery of aged hip fracture patients

Aims. The aims of this study were to evaluate the incidence of postoperatively restricted weight-bearing and its association with outcome in patients who undergo surgery for a fracture of the hip. Patients and Methods. Patient aged > 60 years undergoing surgery for a hip fracture were identified in the 2016 National Surgical Quality Improvement Program (NSQIP) Hip Fracture Targeted Procedure Dataset. Analysis of the effect of restricted weight-bearing on adverse events, delirium, infection, transfusion, length of stay, return to the operating theatre, readmission and mortality within 30 days postoperatively were assessed. Multivariate regression analysis was used to adjust for confounding demographic, comorbid and procedural characteristics. Results. Of the 4918 patients who met inclusion criteria, 3668 (63.53%) were allowed to weight-bear as tolerated postoperatively. Controlling for patient and procedural factors, multivariate odds of any adverse event, major adverse event, delirium, infection, transfusion, length of stay ≥ 75th percentile (six days) and mortality within 30 days were all higher in patients with weight-bearing restrictions. Notably, there were no differences for thromboembolic events, return to the operating theatre or readmission within 30 days between the groups. Conclusion. Elderly patients with a fracture of the hip with postoperative weight-bearing restrictions have a significantly greater risk of developing most adverse events compared with those who are encouraged to weight-bear as tolerated. These findings emphasize the importance of immediate weight-bearing as tolerated to optimize the outcome in these frail patients; however nearly 25% of surgeons fail to meet this evidence-based guideline. Cite this article: Bone Joint J 2018;100-B:1377–84

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

3D accurate measurements of the skeletal structures of the foot, in physiological and impaired subjects, are now possible using Cone-Beam CT (CBCT) under real-world loading conditions. In detail, this feature allows a more realistic representation of the relative bone-bone interactions of the foot as they occur under patient-specific body weight conditions. In this context, varus/valgus of the hindfoot under altered conditions or the thinning of plantar tissues that occurs with advancing age are among the most complex and interesting to represent, and numerous measurement proposals have been proposed. This study aims to analyze and compare these measurements from CBCT in weight-bearing scans in a clinical population. Sixteen feet of diabetic patients and ten feet with severe adult flatfoot acquired before/after corrective surgery underwent CBCT scans (Carestream, USA) while standing on the leg of interest. Corresponding 3D shapes of each bone of the shank and hindfoot were reconstructed (Materialise, Belgium). Six different techniques found in the literature were used to calculate the varus/valgus deformity, i.e., the inclination of the hindfoot in the frontal plane of the shank, and the distance between the ground and the metatarsal heads was calculated along with different solutions for the identification of possible calcifications. Starting with an accurate 3D reconstruction of the skeletal structures of the foot, a wide range of measurements representing the same angle of hindfoot alignment were found, some of them very different from each other. Interesting correlations were found between metatarsal height and subject age, significant in diabetic feet for the fourth and fifth metatarsal bones. Finally, CBCT allows 3D assessment of foot deformities under loaded conditions. The observed traditional measurement differences and new measurement solutions suggest that clinicians should consider carefully the anatomical and functional concepts underlying measurement techniques when drawing clinical and surgical conclusions

Introduction. Instability, loosening, and patellofemoral pain belong to the main causes for revision of total knee arthroplasty (TKA). Currently, the diagnostic pathway requires various diagnostic techniques such as x-rays, CT or SPECT-CT to reveal the original cause for the failed knee prosthesis, but increase radiation exposure and fail to show soft-tissue structures around TKA. There is a growing demand for a diagnostic tool that is able to simultaneously visualize soft tissue structures, bone, and TKA without radiation exposure. MRI is capable of visualising all the structures in the knee although it is still disturbed by susceptibility artefacts caused by the metal implant. Low-field MRI (0.25T) results in less metal artefacts and offers the ability to visualize the knee in weight-bearing condition. Therefore, the aim of this study is to investigate the possibilities of low field MRI to image, the patellofemoral joint and the prosthesis to evaluate the knee joint in patients with and without complaints after TKA. Method. Ten patients, eight satisfied and two unsatisfied with their primary TKA, (NexGen posterior stabilized, BiometZimmer) were included. The patients were scanned in sagittal, coronal, and transversal direction on a low field MRI scanner (G-scan Brio, 0.25T, Esaote SpA, Italy) in weight-bearing and non-weight-bearing conditions with T1, T2 and PD-weighted metal artefact reducing sequences (TE/TR 12–72/1160–7060, slice thickness 4.0mm, FOV 260×260×120m. 3. , matrix size 224×216). Scans were analysed by two observers for:. - Patellofemoral joint: Caton-Descamps index and Tibial Tuberosity-Trochlear Groove (TT-TG) distance. - Prosthesis malalignment: femoral component rotation using the posterior condylar angle (PCA) and tibial rotation using the Berger angle. Significance of differences in parameters between weight-bearing and non-weight-bearing were calculated with the Wilcoxon rank test. To assess the reliability the inter and intra observer reliability was calculated with a two-way random effects model intra class correlation coefficient (ICC). The two unsatisfied patients underwent revision arthroplasty and intra-operative findings were compared with MRI findings. Results. In the satisfied group, a significant difference was found between TT-TG distance in non-weight-bearing and weight-bearing condition (p=0.018), with a good interrater reliability ICC=0.89. Furthermore, differences between weight-bearing and non-weight-bearing were found for the CD ratio, however, not significant (p=0.093), with a good interrater reliability ICC=0.89. The Berger angle could be measured with an excellent interrater reliability (ICC=0.94). The PCA was hard to assess with a poor interrater reliability (ICC=0.48). For one unsatisfied patient a deviation was found for tibial component rotation, according to the perioperative findings as, ‘malposition of the tibial component’. For the other unsatisfied patient revision surgery was performed due to aseptic loosening in which the MRI showed a notable amount of synovitis. Conclusion. It is possible to image the patellofemoral joint and knee prosthesis with low field MRI. Patellofemoral measurements and tibial component rotation measurements can reliably be performed. For the two patients with complaints MRI findings were consistent with intra-operative findings. Further research should focus on a larger group of patients with complaints after TKA to verify the diagnostic capacity of low field MRI for peri-prosthetic knee problems. For any figures or tables, please contact authors directly

Aims. Poly(methyl methacrylate) (PMMA)-based bone cements are the industry standard in orthopaedics. PMMA cement has inherent disadvantages, which has led to the development and evaluation of a novel silorane-based biomaterial (SBB) for use as an orthopaedic cement. In this study we test both elution and mechanical properties of both PMMA and SBB, with and without antibiotic loading. Methods. For each cement (PMMA or SBB), three formulations were prepared (rifampin-added, vancomycin-added, and control) and made into pellets (6 mm × 12 mm) for testing. Antibiotic elution into phosphate-buffered saline was measured over 14 days. Compressive strength and modulus of all cement pellets were tested over 14 days. Results. The SBB cement was able to deliver rifampin over 14 days, while PMMA was unable to do so. SBB released more vancomycin overall than did PMMA. The mechanical properties of PMMA were significantly reduced upon rifampin incorporation, while there was no effect to the SBB cement. Vancomycin incorporation had no effect on the strength of either cement. Conclusion. SBB was found to be superior in terms of rifampin and vancomycin elution. Additionally, the incorporation of these antibiotics into SBB did not reduce the strength of the resultant SBB cement composite whereas rifampin substantially attenuates the strength of PMMA. Thus, SBB emerges as a potential weight-bearing alternative to PMMA for the local delivery of antibiotics. Cite this article: Bone Joint Res 2021;10(4):277–284

Aims. Cone beam CT allows cross-sectional imaging of the tibiofibular syndesmosis while the patient bears weight. This may facilitate more accurate and reliable investigation of injuries to, and reconstruction of, the syndesmosis but normal ranges of measurements are required first. The purpose of this study was to establish: 1) the normal reference measurements of the syndesmosis; 2) if side-to-side variations exist in syndesmotic anatomy; 3) if age affects syndesmotic anatomy; and 4) if the syndesmotic anatomy differs between male and female patients in weight-bearing cone beam CT views. Patients and Methods. A retrospective analysis was undertaken of 50 male and 50 female patients (200 feet) aged 18 years or more, who underwent bilateral, simultaneous imaging of their lower legs while standing in an upright, weight-bearing position in a pedCAT machine between June 2013 and July 2017. At the time of imaging, the mean age of male patients was 47.1 years (18 to 72) and the mean age of female patients was 57.8 years (18 to 83). We employed a previously described technique to obtain six lengths and one angle, as well as calculating three further measurements, to provide information on the relationship between the fibula and tibia with respect to translation and rotation. Results. The upper limit of lateral translation in un-injured patients was 5.27 mm, so values higher than this may be indicative of syndesmotic injury. Anteroposterior translation lay within the ranges 0.31 mm to 2.59 mm, and -1.48 mm to 3.44 mm, respectively. There was no difference between right and left legs. Increasing age was associated with a reduction in lateral translation. The fibulae of men were significantly more laterally translated but data were inconsistent for rotation and anteroposterior translation. Conclusion. We have established normal ranges for measurements in cross-sectional syndesmotic anatomy during weight-bearing and also established that no differences exist between right and left legs in patients without syndesmotic injury. Age and gender do, however, affect the anatomy of the syndesmosis, which should be taken into account at time of assessment. Cite this article: Bone Joint J 2019;101-B:348–352

Biomedical imaging is essential in the diagnosis of musculoskeletal pathologies and postoperative evaluations. In this context, Cone-Beam technology-based Computed Tomography (CBCT) can make important contributions in orthopaedics. CBCT relies on divergent cone X-rays on the whole field of view and a rotating source-detector element to generate three-dimensional (3D) volumes. For the lower limb, they can allow acquisitions under real loading conditions, taking the name Weight-Bearing CBCT (WB-CBCT). Assessments at the foot, ankle, knee, and at the upper limb, can benefit from it in situations where loading is critical to understanding the interactions between anatomical structures. The present study reports 4 recent applications using WB-CBCT in an orthopaedic centre. Patient scans by WB-CBCT were collected for examinations of the lower limb in monopodal standing position. An initial volumetric reconstruction is obtained, and the DICOM file is segmented to obtain 3D bone models. A reference frame is then established on each bone model by virtual landmark palpation or principal component analysis. Based on the variance of the model point cloud, this analysis automatically calculates longitudinal, vertical and mid-lateral axes. Using the defined references, absolute or relative orientations of the bones can be calculated in 3D. In 19 diabetic patients, 3D reconstructed bone models of the foot under load were combined with plantar pressure measurement. Significant correlations were found between bone orientations, heights above the ground, and pressure values, revealing anatomic areas potentially prone to ulceration. In 4 patients enrolled for total ankle arthroplasty, preoperative 3D reconstructions were used for prosthetic design customization, allowing prosthesis-bone mismatch to be minimized. 20 knees with femoral ligament reconstruction were acquired with WB-CBCT and standard CT (in unloading). Bone reconstructions were used to assess congruency angle and patellar tilt and TT-TG. The values obtained show differences between loading and unloading, questioning what has been observed so far. Twenty flat feet were scanned before and after Grice surgery. WB-CBCT allowed characterization of the deformity and bone realignment after surgery, demonstrating the complexity and multi-planarity of the pathology. These applications show how a more complete and realistic 3D geometric characterization of the of lower limb bones is now possible in loading using WB-CBCT. This allows for more accurate diagnoses, surgical planning, and postoperative evaluations, even by automatisms. Other applications are in progress

The effect of weight-bearing on the height of the patellar using four radiological indices was studied in 25 healthy men using lateral radiographs of the knee in 30° of flexion non-weight-bearing and weight-bearing. The position of the patella was quantified using the Insall-Salvati, the modified Insall-Salvati, the Blackburne-Peel and the Caton indices. The contraction of the quadriceps on weight-bearing resulted in statistically significant proximal displacement of the patella with all four indices studied. The mean Insall-Salvati index was 0.919 (. sd. 0.063) before and 1.109 (. sd. 0.042) after weight-bearing (p = 0.001), while the mean modified Insall-Salvati index was 0.734 (. sd. 0.039) before and 0.896 (. sd. 0.029) after weight-bearing (p = 0.041). Similarly, the Blackburne-Peel index was 0.691 (. sd. 0.09) before and 0.807 (. sd. 0.137) after weight-bearing (p = 0.012). The mean Caton index was 0.861 (. sd. 0.09) before and 0.976 (. sd. 0.144) after weight-bearing (p = 0.023). The effect of quadriceps contraction should be considered in clinical studies where the patellar position indices are reported

Introduction. Although weight-bearing CT of the foot definitely reflects the morphology and deformity of joint, it is hard to obtain the standing CT due to difficulty of availability. Although 3D imaging reconstruction using radiographs has been reported in other joints, there is no study about foot joint. The purpose of this study is to develop a semi-automatic method based on a deformable surface fitting for achieving the weight-bearing 3D model reconstruction from standing radiographs for foot. Methods. Our method is based on a Laplacian surface deformation framework using a template model of foot. As pre- processing step, we obtained template surface meshes having the average shapes of foot bones (talus, calcaneus) from standing CT images (Planmed Verity) in 10 normal volunteers. In the reconstruction step, the surface meshes are deformed following guided user inputs with geometric constraints to recover the target shapes of 30 patients while preserving average bone shape and smoothness. Finally, we compared reconstructed 3D model to original standing CT images. Analysis was performed using Dice coefficients, average shape distance, maximal shape distance. Results. The obtained reconstruction model is close to the actual standing foot geometry (Dice coefficients 0.89, average shape distance 0.88 mm, maximum shape distance 6.33 mm). We present the accuracy and robustness of our method via comparison between the reconstructed 3D models and the original bone surfaces. Conclusions. Weight-bearing 3D foot model reconstruction from standing radiographs is concise and the effective method for analysis of foot joint alignment and deformity

We performed two independent, randomised, controlled trials in order to assess the potential benefits of immediate weight-bearing mobilisation after rupture of the tendo Achillis. The first trial, on operatively-treated patients showed an improved functional outcome for patients mobilised fully weight-bearing after surgical repair. Two cases of re-rupture in the treatment group suggested that careful patient selection is required as patients need to follow a structured rehabilitation regimen. The second trial, on conservatively-treated patients, provided no evidence of a functional benefit from immediate weight-bearing mobilisation. However, the practical advantages of immediate weight-bearing did not predispose the patients to a higher complication rate. In particular, there was no evidence of tendon lengthening or a higher re-rupture rate. We would advocate immediate weight-bearing mobilisation for the rehabilitation of all patients with rupture of the tendo Achillis

Background. The complex deformities in cavovarus feet may be difficult to assess and understand. Weight-bearing CT (WBCT) is increasingly used to evaluate complex deformities. However, the bone axes may be difficult to calculate in the setting of severe deformity. Computer-assisted 3D-axis calculation is a novel approach that may allow for more accurate assessment of foot alignment / deformity. The aim of this study was to assess differences in measurements done manually on 2D slices of WBCT versus 3D computer models in normal and cavus feet. Methods. We retrospectively analyzed WBCT scans from 16 normal and 16 cavus feet in patients with Charcot-Marie Tooth. Eight measurements were assessed: Talus-1. st. metatarsal angle (axial plane), Forefoot arch angle (coronal plane), and Meary's angle, calcaneal pitch, cuneiform to floor, cuneiform to skin, navicular to floor and navicular to skin distance (sagittal plane). 2D measurements were performed manually and 3D measurements were performed using specialised software (BoneLogic, DISIOR). Results. There was no significant difference in the measured variables (2D manual versus 3D automated) in normal feet. In the cavus group, 3D assessment calculated increased values for the sagittal angles: Meary's 7.3 degrees greater (p = 0.004), calcaneal pitch 2.4 degrees greater (p = 0.011)), and lower values for the axial talus-1. st. MT angle, 10.6 degrees less (p = 0.001). Conclusion. There were no significant differences in the normal group. This suggests 3D automated techniques can reliably assess the alignment of bony axes. However, the 3D axis calculations suggest there may be greater sagittal and lesser axial deformity in cavus feet than measured by 2D techniques. This discrepancy may be on account of the rotation seen in cavovarus feet, which may not be readily assessed manually. 3D automated measurements may therefore have a role in better assessing and classifying the cavus foot which may ultimately help inform treatment algorithms

Summary Statement. A porcine model using Yucatan minipigs was found to be very promising for the investigation of healing around transcutaneous osseointegrated implants. Pigs demonstrated surprising agility and adaptability including the ability to ambulate on three legs during the immediate postoperative period. Introduction. Previous non weight-bearing and weight-bearing caprine, canine and ovine models have evaluated design, material, and biological coating variations in an attempt to improve the wound healing and skin-implant seal around transcutaneous osseointegrated implants. Although these models have primarily been used as a window into the application of transcutaneous osseointegrated implants in humans, some important model characteristics affecting wound healing and infection have been missing including: 1) replication of the physiological tissue response, and 2) availability of a transcutaneous site with sufficient soft tissue coverage. Pig skin, like human, is relatively hairless, tightly attached to the subcutaneous tissue, vascularised by a cutaneous blood supply, and healed by means of epithelialization. Swine have been extensively utilised for superficial and deep wound healing studies and can offer ample soft tissue coverage following a lower limb amputation. Development of a porcine model is important for continued understanding and improvement of weight-bearing transcutaneous osseointegration. Methods. Two male Yucatan mini-pigs (9 months, 36kg) were fit with transcutaneous osseointegrated prostheses using a single-stage transtibial amputation and prosthesis implantation procedure. The endo-prosthesis consisted of a cylindrical intraosseous threaded section and a smooth transcutaneous section. The transcutaneous sections were smooth to promote epithelialization and deter direct skin-implant adhesion. The implants were custom manufactured from medical grade Ti-6Al-4V alloy. The exo-prosthesis, consisting of an adjustable length leg and foot, was attached by clamp to the supercutaneous portion of the implant following either one or two days of sling constraint to limit initial weight-bearing. Various exo-prosthesis designs and configurations were trialed. The animals’ behavior and gait were closely observed. Weight-bearing was monitored using a force plate. At 5 and 8 weeks, clinical, microbiological, and histological data were examined to assess wound healing and infection at the skin-bone-implant interface. Results. The pigs demonstrated surprising agility and adaptability. They were able to successfully ambulate on three legs during the post-op period before weight-bearing was permitted. They adapted quickly to changes in exo-prosthesis design, position, and length. Although bacterial colonization was verified, neither of the animals exhibited clinical signs of infection over the respective eight and five week studies. Histological results indicated that there was no skin to implant adhesion but that epithelial growth was progressing towards the implant in one animal. Healing of the transcutaneous wound site showed substantial progress but a definitive skin seal was non-existent at the eight week time point. Discussion/Conclusion. This is likely the first animal model developed, having soft tissue characteristics similar to those found in humans, in which an axially-loaded, weight-bearing implant was successfully used. Results indicated that this porcine model offers many advantages over previous models for the development, evaluation, and comparison of the various techniques being advocated to achieve successful transcutaneous osseointegration in humans. The Yucatan miniature pig's ability to ambulate on three legs during the immediate post-operative period and quickly adjust to changes in the exo-prosthesis design, coupled with their physiological similarity to humans, makes them a valuable model for future studies

We developed a novel silorane-based biomaterial (SBB) for use as an orthopedic cement. SBB is comprised of non-toxic silicon-based monomers, undergoes non-exothermic polymerization, and has weight-bearing strength required of orthopedic cements. We sought to compare the antibiotic release kinetics of this new cement to that of commercially available PMMA bone cement. We also evaluated each material's inherent propensity to support the attachment of bacteria under both static and dynamic conditions. One gram of either rifampin or vancomycin was added to 40g batches of PMMA and SBB. Pellets were individually soaked in PBS. Eluate was collected and tested daily for 14 days using HPLC. Compressive strength and modulus were tested over 21 days. Bioassays were used to confirm the bioactivity of the antibiotics eluted. We measured the growth and maturation of staphylococcus aureus (SA) biofilm on the surface of both PMMA and SBB disks over the course of 72 hours in a static well plate and in a dynamic biofilm reactor (CDC Biofilm Reactor). N=4 at 24, 48, and 72 hours. A luminescent strain of SA (Xen 29) was employed allowing imaging of bacteria on the discs. SBB eluted higher concentrations of vancomycin than did PMMA over the course of 14 days (p<0.001). A significant 55.1% greater day 1 elution was observed from SBB. Silorane cement was able to deliver rifampin in clinically favorable concentrations over 14 days. On the contrary, PMMA was unable to deliver rifampin past day 1. The incorporation of rifampin into PMMA severely reduced its mechanical strength (p<0.001) and modulus (p<0.001). Surface bacterial radiance of PMMA specimens was significantly greater than that of SBB specimens at all time points (p<0.05). The novel silorane-based cement demonstrated superior antibiotic release and, even without antibiotic incorporation, demonstrated an innate inhabitation to bacterial attachment and biofilm

We studied the effect of full and partial weight-bearing on venous peak velocity in the legs of 73 subjects. We used colourflow Duplex ultrasound to determine the minimal amount of weight-bearing required to produce the same venous peak velocity as full weight-bearing. We found that the venous peak velocity remains the same in the femoral vein during partial weight-bearing (196 N and above). This is important for postoperative physiotherapy and thrombo-prophylaxis. The median peak velocity was 30 cm/s. This corresponds to an amplification factor of four in relation to the individual resting level (peak velocity). In addition, we found that partial weight-bearing at 196 N can reliably be reproduced. The median value of partial weight-bearing after a three-day training programme was 206 N

1. A specially designed loading apparatus and dyeing technique have been used to demonstrate the weight-bearing areas in fifty-one normal adult hip joints. 2. Under loads and positions typical of the stance phase of walking the entire articular surface of the acetabulum is involved in weight-bearing. This contact area is reproduced on the femoral head, and its position determined by the attitude of the femur to the acetabulum. 3. With loads typical of the swing phase, the dome of the acetabulum and corresponding areas on the femoral head are not involved in weight-bearing. 4. The results are compared with the conclusions of previous investigators and their possible significance with regard to joint degeneration is discussed