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Load-bearing biological materials employ specialized elastic bridging regions to connect material parts with substantially different properties. While such bridging regions emerge in diverse systems of biological systems, their functional-mechanical origins are yet disclosed. Here, we hypothesize that these elastic bridging regions evolved primarily to minimize the near-interface stress effects in the biological material and, supported by experiments and simulations, we develop a simple theoretical model for such stress-minimizing bridging modulus. Our theoretical model describes well extensive experimental data of diverse biomechanical systems, suggesting that despite their compositionally distinct bridging regions, they share a similar mechanical adaptation strategy for stress minimization. The theoretical model developed in this study may directly serve as a design guideline for bio-inspired materials, biomedical applications, and advanced interfacial architectures with high resilience to mechanical failure. STATEMENT OF SIGNIFICANCE: Biological materials exhibit unconventional structural-mechanical strategies allowing them to attain extreme load-bearing capabilities. Here, we identify the strategy of biological materials to connect parts of distinct elastic properties in an optimal manner of stress minimization. Our findings are compatible with broad types of biological materials, including biopolymers, biominerals, and their bio-composite combinations, and may promote novel engineering designs of advanced biomedical and synthetic materials.

While open reduction and internal fixation is currently considered the optimum treatment option for displaced ankle fractures, the most optimal post-operative rehabilitation strategy in this setting remains unclear. The objective of this investigation was to compare the effect of early vs. late weight bearing and ankle mobilization in the post-operative management of ankle fractures.Medline, Embase, CENTRAL, Scopus, CINHAL, and Web of Science were searched to identify randomized controlled trials (RCTs) and quasi-RCTs. Two review authors screened articles, abstracted data, and evaluated risk of bias in duplicate. Outcomes of interest included post-operative ankle function and overall time to return to work. Studies on weight bearing and ankle mobilization were analysed separately and all data were pooled using random-effects models.Eighteen trials were included in the review of which 14 were included in the meta-analysis of at least one outcome of interest. Majority of the studies presented a high overall risk of bias. Early weight bearing demonstrated significantly better short-term postoperative functional scores at 6-9 weeks postoperatively (SMD: 0.39, 95% CI: 0.19, 0.58; p 0.0001; IOur findings suggest a potential role of EWB in improving post-operative ankle-function in the short-term and reducing the overall time to return to work/daily activities, but no clinical benefit associated with early ankle mobilization post-surgery.

Retrospective cross-sectional case series.Lesions of the triangular fibrocartilage complex (TFCC) can result in pain during axial load and unstable distal radioulnar joint (DRUJ). Conventional wrist orthoses decrease initial pain sufficiently but also prevent any movement during recovery and do not contribute to the stabilization of the DRUJ.In this retrospective analysis, we tested if the weight-bearing capacity of patients with lesions of the triangular fibrocartilage complex was increased by wearing a brace that stabilizes the distal radioulnar joint.Twenty-three patients had an arthroscopically confirmed TFCC lesion. We compared preoperative dynamic weight-bearing capacity of both hands with and without a commercially available wrist brace (WristWidget). Subgroup analysis was performed for stability of the distal radioulnar joint and etiology of the TFCC lesion. The dynamic ulnar variance was measured in a modified weight bearing test. We used parametric tests for normally distributed values.The weight-bearing capacity of the hand with TFCC lesion was significantly lower than of the control hand (16 verus 36 kg; p0.001). The relative load of the affected hand compared to the unaffected hand increased from 48 % (CI 37-60, SD 27) to 59 % (CI 47-72, SD 29 with a brace. The device had no effect on the control hand. Twelve patients with unstable DRUJ had a lower weight-bearing capacity compared to the eleven with stable joint. The percentage improvement with bracing was higher for those with unstable joints (versus stable) and traumatic lesions (versus degenrative).The use of a wrist brace significantly increases the weight-bearing capacity and therefore the maximum tolerated axial load of patients with a lesion of the TFCC. Patients with traumatic lesion or unstable DRUJ tend to show lower values than with degenerative lesions or stable joints.

Objectives: To evaluate the effect of in-lab simulation of CAD/CAM grinding and intaglio surface treatments on the surface characteristics (topography and roughness) and fatigue behavior of adhesively luted 4YSZ simplified restorations. Methods: Ceramic discs (Ø = 10 mm, thickness = 1 mm) were randomly allocated into 6 groups considering: “In-lab simulation of CAD/CAM grinding” (ground or polished) and “intaglio surface treatments”: Ctrl (without surface treatment), AlOx (aluminum oxide air abrasion) or GLZ (glaze spray application). The surface roughness of all samples was measured, the treated discs received a ceramic primer, were luted with resin cement onto a dentin analogue material (woven glass-reinforced epoxy resin) and tested under a cyclic fatigue test (step-stress approach, n = 15; 1.4 Hz, 10,000 cycles/step, step-size of 100N starting at 200N until failure). A complementary analysis was performed to corroborate the findings in the fatigue test that the glaze fill defects increase the mechanical properties of the ceramic. To do so, bars (n= 10; 1.0 × 1.0 × 12 mm; considering the groups: N-ID: non-indented; ID: indented; ID-GLZ: indented plus glaze spray application) were indented in a vickers hardness tester to produce a crack pattern, treated with glaze or not, and then submitted to flexural strength tests (FS). Fractographic and topographic analysis were performed. Results: In-lab simulation of CAD/CAM grinding decreased the fatigue failure load of the 4YSZ ceramic when comparing polished and ground groups, regardless of surface treatment. GLZ induced better fatigue performance compared to the air abrasion, regardless of the grinding condition (ground or polished surface). The results of the flexural strength test corroborated the findings in the fatigue test, as the ID-GLZ group presented superior FS than the ID group, however both had inferior FS than N-ID. There is an inverse association between roughness and fatigue failure load, as the higher the surface roughness, the lower the fatigue failure load. Failures in the fatigue and flexural strength tests started from the face subjected to tensile stresses. Conclusion: In-lab simulation of CAD/CAM grinding had a detrimental effect on the fatigue behavior of 4YSZ and glaze spray induced better 4YSZ performance compared to the air abrasion. The intaglio surface treatments differently influenced the 4YSZ fatigue performance, however, only glaze spray can reverse the damage caused by the grinding.

As a flexible and elastic structure, the dynamic morphometry of medial longitudinal arch remains to be an unresolved Issue for clinic. Here we introduce a new measurement named arch volume to describe the morphological changes of the medial longitudinal arch during weight-bearing and compare with present method for measuring MLA.64 healthy participants were enrolled. And the dynamic arch morphology was measured under four weight bearing status with navicular height, arch area and arch volume, respectively.With the increase of weight loading, the flattening or slightly deformation of medial longitudinal arch was observed by all method (p0.05). However, as a 3D indicator, arch volume not only showed higher sensitivity than other method, but also provide visualization of MLA during loading changing.Compared with navicular height and arch area, arch volume has a significant advantage in describing arch morphological changes under different weight bearing status.

Several studies have explored the effect of backpack carriage on physiologic responses while walking, but few have focused specifically on the influence of the use of a hip strap on these responses. The aim of this study was to investigate the effect of a backpack hip strap on physiologic responses when walking at a moderate intensity while carrying a backpack with a standardized relative load of 30% of the wearer's body mass.Twenty-three healthy, active participants carrying backpacks walked on a treadmill at a speed and grade that elicited 40-50% of their heart rate reserve. Participants completed 2 counterbalanced 30-min trials, one with the hip strap in the strapped condition and one with the hip strap unfastened. Metabolic, heart rate, blood pressure, and muscle oxygen saturation (SmONo differences were found between strapped and unstrapped trials for oxygen consumption (strapped 21.9±4.2 mL·kgThese results suggest that wearing a hip strap does not influence physiologic responses up to 30 min of moderate intensity walking while carrying 30% of the wearer's mass.

Understanding plain radiograph in association with 3-dimensional (3D) morphology of the ankle is essential for treatment about varus ankle osteoarthritis (OA). The aims of this study were to investigate whether the alignment of the tibial plafond as determined on plain radiograph reflected the alignment of the tibial plafond on computed tomography (CT) in varus ankle OA and whether the alignment of the tibial plafond changed as the OA progressed. The 3D CT and plain radiographs from 101 ankles with varus ankle OA were analyzed and compared with 40 ankles in control group. The tibial plafond was assessed in the coronal and sagittal planes using 3D CT. The medial angle between the vertical line and the tibial plafond was measured on 3 different coronal plane CT images which was anterior, middle and posterior area of the tibial plafond. The medial distal tibial angle on plain radiograph reflected the posterior area of the tibial plafond on CT. The amount of varus angulation on CT was larger in anterior and middle area of the tibial plafond than the posterior area. There was a difference in the degree of varus of the tibial plafond between control group and OA patients; however, there was no difference among patients in different stages of varus ankle OA. Weightbearing plain radiographs underestimate the varus deformity in anterior and middle area of the tibial plafond and there is no significant difference in deformity of the tibial plafond among patients in different stages of varus ankle OA.

Chronic low back pain due to manual lifting continues to be one of the significant common public health challenges in modern societies despite increased automation. While there are extensive studies on the biomechanics of lifting as associated with LBP, the role of unstable and time-varying dynamic loads, quite common in industrial lifting and daily life, remains elusive.The present study aimed to investigate the response of trunk muscles in subjects with chronic non-specific low back pain (CNLBP) while holding unstable dynamic loads.Twelve male patients with CNLBP and twelve healthy controls participated in this cross-sectional study. The subjects held static and dynamic loads in neutral positions. Normalized EMG data of the trunk muscles were captured and analyzed by repeated-measures ANOVA test.The low back pain group demonstrated significantly higher activation levels of the internal and external abdominal oblique muscles while holding dynamic loads (p 0.05).Our results suggest that the neuromusculoskeletal system in low back patients holding dynamic loads may invoke a motor control strategy that significantly increases muscle co-activation leading to higher joint stiffness at the expense of higher compressive loads on the lumbar spine. Importantly, the type of load plays a critical role in terms of external perturbations that may lead to spinal injury in CNLBP patients and must, therefore, be considered in the risk prevention and assessment of lifting and other manual material handling tasks.

Surgical repair of acute mid-substance Achilles tendon ruptures is performed in active patients, but the postoperative rehabilitation program is often based on the experience of the surgeon or therapist, rather than on evidence-based protocols. The aim of the study is to establish an evidence-based protocol for rehabilitation. This study is a consensus statement. The "GAIT" study group (German, American, and Italian Tendon), an informal collection of 4 experienced foot and ankle surgeons, met to address the question of what items they felt were important relative to rehabilitate a surgically repaired Achilles tendon acute rupture. Thirty-three statements were formulated. A value of 100% agreement by all the members was set to produce a proposed consensus statement. A value of 80% consensus was set to produce "strong recommendation." A systematic review of the literature was also performed. The GAIT group reach 100% agreement on the average postoperative non-weightbearing for 2.3 weeks, the foot in plantarflexion for the first 4 weeks, avoiding ROM exercises beyond neutral, and both stretching and eccentric exercise, not started before 12 weeks. Concentric bilateral heel raises should be performed after 6 weeks, and the average return to initiate sports, was 24.4 weeks. The use of a 1/8

Radiographic measurements are an essential tool to determine the appropriate surgical treatment and outcome for Hallux Valgus (HV). HV deformity is best evaluated by weight-bearing computed tomography (WBCT). The objective was (1) to assess the reliability of WBCT computer-assisted semi-automatic imaging measurements in HV, (2) to compare semi-automatic with manual measurements in the setting of an HV, and (3) to compare semi-automatic measurements between HV and control group.In this retrospective IRB (ID# 201904825) approved study, we assessed patients with hallux valgus deformity. The sample size calculation was based on the hallux valgus angle (HVA). Thus to obtain the 0.8 power, including 26 feet with HV in this study, was necessary. Our control group consisted of 19 feet from 19 patients without HV. Raw multiplanar data was evaluated using software CubeVue®. In the axial plane, hallux valgus angle (HVA), intermetatarsal angle (IMA), and interphalangeal angle (IPA) were measured. The semiautomatic 3D measurements were performed using the Bonelogic®Software. Inter-rater reliabilities were performed using ICC. Agreement between methods was tested using the Bland-Altman plots. The difference between Patologic and Control cases using semi-automatic measurements was assessed with the Wilcoxon signed-rank test. Alpha risk was set to 5% (α = 0.05). P ≤ 0.05 were considered significant.Reliabilities utilizing ICC were over 0.80 for WBCT manual measurements and WBCT semi-automatic readings. Inter and intraobserver agreement for Manual and Semi-automatic WBCT measurements demonstrated excellent reliability.Semi-automatic measurements are reproducible and comparable to measurements performed manually. The software differentiated pathological from non-pathological conditions when subjected to semi-automatic measurements. The development of advanced semi-automatic segmentation software with minimal user intervention is essential for the establishment of big data and can be integrated into clinical practice, facilitating decision-making.

This study aimed to evaluate the permissible joint-line obliquity (JLO) based on radiologic and clinical outcomes with midterm follow-up after medial open-wedge high tibial osteotomy (MOWHTO).Patients who had undergone MOWHTO from March 2014 to May 2016 were retrospectively evaluated. They were divided into 4 groups based on JLO as represented by postoperative medial proximal tibial angle (MPTA). Radiologic parameters including MPTA, joint-line orientation angle (JLOA), joint-line convergence angle (JLCA), posterior tibial slope, weightbearing line ratio (WBLR), and coronal translation were analyzed. Clinical outcomes were evaluated with American Knee Society Score (AKSS), Western Ontario and McMaster University Index, and short-form 36 health survey (SF-36). The changes between preoperation and final follow-up in JLOA and MPTA were defined as ΔJLOA and ΔMPTA.A total of 135 knees were finally included (MPTA ≤90.32° as group I; 90.33° to 92.62° as group II; 92.74° to 95.22° as group III; and ≥95.23° as group IV). The last follow-up MPTA, JLOA, and JLCA values were different between the groups (P.001, P.001, and P = .015, respectively). WBLR and JLOA positively correlated with MPTA; however, WBLR showed an abrupt increase at MPTA96.5°, and the JLOA distribution tended to be greater than the regression line at MPTA96°. Moreover, ΔJLOA was not as large as ΔMPTA. The percentage of patients attaining a minimal clinically important difference was significantly lower in the AKSS-functional score and SF-36 physical component summary in group IV (P = .008 and 0.021, respectively).The JLOA did not change as much as the MPTA, but an MPTA95.2° abruptly increased the JLOA and valgus overcorrection after MOWHTO. Poor clinical outcomes were more evident in excessive MPTA (95.2°) than in mildly undercorrected or properly corrected MPTA (95.2°).III, retrospective cohort study.

The incidence of Achilles tendon rupture is increasing. Postoperative rehabilitation after repairing acute Achilles tendon rupture is very important because the choice of treatment during the rehabilitation period can influence the results. Moreover, the method of functional rehabilitation varies and is developing steadily. Recent studies recommend a functional rehabilitation protocol, and this approach is accepted widely. This study aimed to introduce our most accelerated functional rehabilitation protocol following surgery for acute Achilles tendon rupture and to review the results retrospectively. From July 2014 to July 2016, 67 patients underwent surgery for acute Achilles tendon rupture by one surgeon. Age, sex, body mass index, injury mechanism, rehabilitation method and progress, time to return to previous physical activity, and complications were evaluated. The mean time to be able to squat fully was 10 ± 4.7 (4-20) weeks. Full squatting was possible in 92.8% (52 patients). The mean time to perform a single-limb heel rise and repetitive single-limb heel rise was 12.6 ± 3.9 (6-24) and 23.3 ± 7.7 (8-40) weeks, respectively. The mean time to return to sports was 20.6 ± 5.2 (12-32) weeks. The major complication rate was 3.5% (one re-rupture and one tendon elongation). The mean pre- and postoperative Achilles Tendon Total Rupture Score was 29.5 ± 3.7 (20-38) and 79.3 ± 18.5 (20-98) points, respectively. The increase was significant (p < .01). In conclusion, immediate full weightbearing and ankle motion exercise after repair of acute Achilles tendon rupture can provide a good rehabilitation option with a low re-rupture rate and satisfactory functional results.

Soft tissue defects in the weight-bearing heel represent a reconstructive challenge because of tissue complexity and lack of local/regional coverage. This study presents our reconstruction outcomes of different defect aetiologies, reconstruction timing, and flap selection.Patients with weight-bearing heel defects who underwent free tissue transfer from 2003 to 2014 and with at least 6 months of follow-up were retrospectively reviewed. Flap types (fasciocutaneous vs muscle/musculocutaneous), timing of reconstruction (early vs subacute vs delayed), and defect aetiology were compared in terms of flap failure, vascular complications, and ulceration.Seventy-four flaps were used to reconstruct weight-bearing heel defects in 70 patients. Defect aetiology included trauma in 53 patients (75%), chronic wound in 12 patients (17%), and tumour resection in 6 patients (8%). Flap survival was 97% (72/74). There was no significant difference in flap failures between muscle and fasciocutaneous flaps. The timing of reconstruction showed no difference in flap survival. There was a significant difference in ulceration rate between the trauma and non-trauma groups (p = 0.001). Twenty-eight ulcers (39%) developed, 12 (43%) of which presented 3 years postoperatively, while only 6 cases (21%) presented within one year postoperatively.Our experience represents one of the highest survival rates reported regarding free flap weight-bearing heel reconstruction. The anterolateral thigh flap was our first choice for extensive heel defects. Ulceration incidence was directly related to trauma and tends to develop 3 years after reconstruction. Delayed reconstruction was at least as safe as early or subacute reconstruction though with less need for debulking.

Diabetes increases the risk of developing postoperative complications such as superficial and deep infection, wound dehiscence, and revisional surgery. Prolonged non-weightbearing and/or augmented fixation may reduce postoperative complications in complicated diabetic ankle fractures. This study's purpose was to compare the development of postoperative infection, wound dehiscence, and revisional surgery in complicated diabetic ankle fractures with respect to weightbearing status. We hypothesized that fewer complications would occur in patients with prolonged non-weightbearing. Medical records of 90 surgically treated complicated diabetic ankle fractures were retrospectively reviewed for postoperative radiographs, weightbearing status, and complications. Complicated diabetes was defined as HbA1c ≥ 8% within 1 year of surgery. Twenty-four out of 90 patients had prolonged non-weightbearing status, which was defined as ≥ 8 weeks of non-weightbearing postoperatively. Twelve out of 90 patients had augmented fixation, which was defined as standard open reduction and internal fixation plus ≥ 2 tetra-cortical or > 2 tri-cortical syndesmotic screws with medial plate, external fixation, or other combination. Thirty-three out of 90 patients (36.7%) patients developed complications postoperatively. Patients with prolonged non-weightbearing had less complications (29.2% vs 39.4%, p = .37) and larger HbA1c values compared with early weightbearing patients (10.0 vs 9.3, p = .04). A one-unit increase in creatinine value (mg/dL) revealed a 3.15-fold increase in development of complications (95% confidence interval 1.29-7.65, p = .01). Although not statistically significant, complicated diabetic ankle fractures treated with prolonged non-weightbearing had less complications postoperatively except for ankle Charcot. Creatinine can be utilized as an independent risk factor for postoperative complications in this population.

The standard for diagnostic radiographic imaging in foot and ankle surgery was until 2012 radiographs with full weight-bearing without any useful alternative. Weight-bearing cone-beam computed tomography (WBCT) was introduced 2012 for foot and ankle use as a new technology that allows 3D imaging with full weight-bearing which should be not influenced by projection and/or foot orientation. The assessment of ankle osteoarthritis with WBCT including the description of healthy status, effect of alignment and7or (in)stability is extensively illustrated in this review article.

Summary Objective In knee cartilage from patients with osteoarthritis (OA), both preserved cartilage and damaged cartilage are observed. In this study, we aim to compare preserved with damaged cartilage to identify the molecule(s) that may be responsible for the mechanical loading-induced differences within cartilage degradation. Methods Preserved and damaged cartilage were harvested from the same OA knee joint. RNA Sequencing was performed to examine the transcriptomic differences between preserved and damaged cartilage cells. Estrogen receptor-α (ERα) was identified, and its function of was tested through gene knockin and knockout. The role of ERα in mediating chondrocyte response to mechanical loading was examined via compression of chondrocyte-laded hydrogel in a strain-controlled manner. Findings from the studies on human samples were verified in animal models. Results Level of estrogen receptor α (ERα) was significantly reduced in damaged cartilage compared to preserved cartilage, which were observed in both human and mice samples. Knockdown of ESR1, the gene encoding ERα, resulted in an upregulation of senescence- and OA-relevant markers in chondrocytes. Conversely, knockin of ESR1 partially reversed the osteoarthritic and senescent phenotype of OA chondrocytes. Using a three-dimensional (3D) culture model, we demonstrated that mechanical overload significantly suppressed ERα level in chondrocytes with concomitant upregulation of osteoarthritic phenotype. When ESR1 expression was suppressed, mechanical loading enhanced hypertrophic and osteogenic transition. Conclusion Our study demonstrates a new estrogen-independent role of ERα in mediating chondrocyte phenotype and its response to mechanical loading, and suggests that enhancing ERα level may represent a new method to treat osteoarthritis.

Background Varus knee correction may affect the ankle and subtalar joints and impact the prognosis of ankle arthritis because the weight-bearing load on the lower extremity extends from the hip to the foot. We aimed to evaluate the changes in the mechanical axis and the weight-bearing axis of the ankle after varus knee surgery. Methods Patients with a varus knee were followed up after undergoing high tibial osteotomy or total knee replacement arthroplasty. The inclusion criteria were age (>18 years) and a history of preoperative and postoperative scanograms. The postoperative change to the ankle joint axis point on the mechanical axis and weight-bearing axis according to the hip–knee–ankle angle correction was adjusted by multiple factors using a linear mixed model. Results Overall, 257 limbs from 198 patients were evaluated. The linear mixed model showed that the change in the ankle joint axis point on the mechanical axis was not statistically significant after high tibial osteotomy and total knee replacement arthroplasty (p = 0.223). The ankle joint axis point on the weight-bearing axis moved laterally by 0.9% per degree of postoperative hip–knee–ankle angle decrease (p Conclusions Varus knee correction could affect the subtalar joint and the ankle joint. Our findings require consideration when utilized during pre- and postoperative evaluations using the weight-bearing axis of patients undergoing varus knee correction.

The optimal treatment and rehabilitation strategy for Achilles tendon ruptures is still under debate. There is a paradigm shift toward early mobilization and weightbearing. We examined the treatment effect of accelerated functional rehabilitation in nonoperative management of acute Achilles tendon ruptures. A systematic search of PubMed, EMBASE, and Web of Science databases for articles comparing accelerated versus delayed rehabilitation in the nonoperative management of acute Achilles tendon rupture was performed. Outcomes of interest were Achilles tendon rupture score (ATRS) (standardized patient-reported instrument related to symptoms and physical activity after treatment of an acute Achilles tendon rupture), rerupture rate, strength, range of motion, return to work, and sports. A total of 2001 articles were identified using our search strategy. We included 6 randomized controlled trials of interest. Although the concept of accelerated rehabilitation has gained popularity in recent years, no statistically significant differences could be revealed in any of the outcomes of interest. We performed a meta-analysis on the following outcomes: ATRS (mean difference -0.93 95% confidence interval [CI] -6.01 to 4.14), Rerupture rate (odds ratio [OR] 0.97, 95% CI: 0.46-2.03), Return to sports (OR 1.31, 95% CI 0.76-2.25), Return to work (mean difference 5.24, 95% CI to -12.04 to 22.51). The treatment effect of accelerated rehabilitation in nonoperatively treated patients seems to be small. However, we recommend accelerated rehabilitation for all conservatively treated patients, because it is a safe option and no detrimental effects have been described in the literature. Furthermore, many patients prefer this type of rehabilitation to avoid the practical disadvantages of prolonged immobilization.

Made available in DSpace on 2022-04-28T19:43:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 The objective of this study was to identify predictors of 12-mo areal bone density accrual in different body segments, lean soft tissue, and osteogenic characteristics attributed to sports participation among adolescent girls and boys. Adolescents (Girls [n = 64], [aged = 14.7]); Boys [n = 129], [aged = 14.6]) were stratified into three groups according to their engagement in different sports (Control [n = 68], Swimming [n = 25], and Weight-bearing sports [n = 100]). Areal bone density (aBMD [g/cm²]) and lean soft tissue (LST) [kg] were measured by dual-energy x-ray absorptiometry (DXA; Lunar DPX-NT; General Electric Healthcare, Little Chalfont, Buckinghamshire, United Kingdom). The ground reaction force (GRF) index attributed to sports participation (Sport-GRF) was created considering the GRF attributed to each sport, body weight of the adolescent, and the amount of time spent in sports participation. Osteocalcin levels (ng/mL) were estimated from a venous blood sample. Multiple regression analysis showed that after adjusting for covariates, the models involving sport-GRF, LST (Δ), and osteocalcin explained 15.8% to 76.2% of the aBMD gains. Specifically in girls, OC was only associated with lower limb aBMD accrual. In boys, however, sport ground reaction forces were positively associated with total spine aBMD accrual. Furthermore, the LST (Δ) was positively associated with aBMD accrual in all body sites (β = 0.003 to 0.011) in both sexes. Increases in LST contributed significantly to gains in aBMD accrual in both sexes, being a more important predictor of changes in bone outcomes than ground reaction forces and osteocalcin. Post-Graduation Program in Movement Sciences Sao Paulo State University (UNESP) Laboratory of InVestigation in Exercise LIVE Department of Physical Education Sao Paulo State University (UNESP) Amsterdam UMC Amsterdam Public Health Research Institute Post-Graduation Program in Movement Sciences Sao Paulo State University (UNESP) Laboratory of InVestigation in Exercise LIVE Department of Physical Education Sao Paulo State University (UNESP)

Background The objective of this study was to evaluate the correlation between Weightbearing CT (WBCT) markers of pronounced peritalar subluxation (PTS) and MRI findings of soft tissue insufficiency in patients with flexible Progressive Collapsing Foot Deformity (PCFD). We hypothesized that significant correlation would be found. Methods Retrospective comparative study with 54 flexible PCFD patients. WBCT and MRI variables deformity severity were evaluated, including markers of pronounced PTS, as well as soft tissue degeneration. A multiple regression analysis and partition prediction models were used to evaluate the relationship between bone alignment and soft tissue injury. P-values of less than .05 were considered significant. Results Degeneration of the posterior tibial tendon was significantly associated with sinus tarsi impingement (p = .04). Spring ligament degeneration correlated to subtalar joint subluxation (p = .04). Talocalcaneal interosseous ligament involvement was the only one to significantly correlate to the presence of subfibular impingement (p = .02). Conclusion Our results demonstrated that WBCT markers of pronounced deformity and PTS were significantly correlated to MRI involvement of the PTT and other important restraints such as the spring and talocalcaneal interosseus ligaments. LEVEL OF EVIDENCE: Level III, Retrospective comparative study.

Osteoporosis is one of the most common skeletal diseases, but current therapies are limited to generalized antiresorptive or anabolic interventions, which do not target regions that would benefit from improvements to skeletal health. To improve the evaluation of treatment plans, we used a spatio-temporal multiscale approach that combines longitudinal in vivo micro-computed tomography (micro-CT) and in silico subject-specific finite element modeling to quantitatively map bone adaptation changes due to disease and treatment at high resolution. Our findings show time and region-dependent modifications in bone remodelling following one and two sets of mechanical loading and/or pharmacological interventions. The multiscale results highlighted that the distal section was unaffected by mechanical loading alone but the proximal tibia had the greatest gain from positive interactions of combined therapies. Mechanical loading abated the catabolic effect of PTH, but the main benefit of combined treatments occurred from the additive interactions of the two therapies in periosteal apposition. These results provide detailed insight into the efficacy of combined treatments, facilitating the optimisation of dosage and treatment duration in preclinical mouse studies, and the development of novel interventions for skeletal diseases. Statement of Significance Combined mechanical loading and pharmacotherapy have the potential to slow osteoporosis-induced bone loss but current therapies do not target the regions in need of strengthening. We show for the first time spatial region-dependant interactions between PTH and mechanical loading treatment in OVX mouse tibiae, highlighting local regions in the tibia that benefitted from separate and combined treatments. Combined experimental-computational analysis also detailed the lasting period of each treatment per location in the tibia, the extent of positive (or negative) interactions of the combined therapies, and the impact of each treatment on the regulation of bone adaptation spatio-temporally. This approach can be used to create hypothesis about the interactions of different treatments to optimise the design of biomaterials and medical interventions.

Objectives Increased tibial axial acceleration and reduced shock attenuation are associated with running injuries and are believed to be influenced by surface type. Trail running has increased in popularity and is thought to have softer surface properties than paved surface, but it is unclear if trail surfaces influence tibial acceleration and shock attenuation. The purpose of this study was to investigate peak triaxial and resultant tibial acceleration as well as axial and resultant shock attenuation among dirt, gravel, and paved surfaces. Design Fifteen recreational runners (12 females, 3 males, age = 27.7 ± 9.1 years) ran over dirt, gravel, and paved surfaces in a trail environment while instrumented with triaxial tibial and head accelerometers. Methods Differences between tri-planar peak tibial accelerations (braking, propulsion, axial, medial, lateral, and resultant) and shock attenuations (axial and resultant) among surface types were assessed with one-way ANOVAs with Bonferroni post-hoc tests. Results No significant differences were found for tibial accelerations or shock attenuations among surface types (p > 0.05). Conclusions Dirt and gravel trail running surfaces do not have lower tibial accelerations or greater shock attenuation than paved surfaces. While runners are encouraged to enjoy the psychological benefits of trail running, trail surfaces do not appear to reduce loading forces associated with running-related injuries.

Plantar callosities under lesser metatarsals are often accompanied by the hallux valgus, and the cause of callosity is thought to be associated with the foot deformity, such as the metatarsal length discrepancy, the abnormal metatarsal head height, cavus, flat foot, and rheumatoid conditions. However, it is unclear which variable is most involved in the cause of callosity in hallux valgus deformity. To clarify the factors associated with the callosity with hallux valgus deformity, we conducted multiple image assessments based on weightbearing radiography and computed tomography. A retrospective review was performed based on the collection of clinical records from all patients with hallux valgus treated from 2010 to 2019 in our institution. We measured the hallux valgus angle, intermetatarsal angles, calcaneal pitch angles, talo-first metatarsal angles, metatarsal length, metatarsal head height, first metatarsal pronation angles, and sesamoid position with weightbearing radiography and computed tomography. We analyzed the relation between callosity formation and imaging assessments using univariate and multivariate logistic regression models. Fifty feet were retrospectively evaluated, and multiple logistic analyses by the stepwise method revealed that the first metatarsal-lateral-sesamoid distance was the only radiographical variable associated with callosity formation among all the tested variables (p .001). As the grade of the callosity became more severe, the lateral shift of the lateral sesamoid increased. The position of the sesamoid bone appears to have a critical role in the assessment and choice of treatment protocols and further research needs to be conducted on the relationship with the position of sesamoid bone to elucidate the mechanism of callus formation.

Objectives Ankle injuries are common in professional football and have profound player/team/club consequences. The weight-bearing lunge-test (WBLT) assesses ankle dorsiflexion range-of-motion in football primary/secondary injury prevention and performance contexts. Data for uninjured and previously ankle-injured players in the English Premier League (EPL) is not available. This study analysed WBLT measurements (cm) within and between uninjured and previously severe ankle-injured players (injured-stiff group, injured-lax group) in one EPL club. Design Cross-sectional. Setting Preseason. Participants Forty-nine players (age 22.9 ± 4.6 yr; height 181.6 ± 5.2 cm; mass 77.7 ± 7.6 kg). Main outcome measures Prevalence (%) of previous unilateral severe ankle injury (USAI). Side-to-side (right/left, dominant/nondominant, injured/uninjured) WBLT comparisons at group-level (t-test [within-group]; Welch's ANOVA [between-group]; effect sizes [within-/between-group]) and individual-level (limb symmetry index [%]; absolute-asymmetry [%]). Results Prevalence of USAI was 38.7%. There were no statistically-significant side-to-side differences for within-/between-group comparisons. Effect sizes: just-below-large (injured-stiff) and extremely-large (injured-lax) for within-group injured-side/uninjured-side comparisons; just-below-medium (injured-lax) to just-above-medium (injured-stiff) for injured-side comparisons to uninjured players. Absolute-asymmetries: uninjured players, 15.4±13.2%; injured-stiff, 21.8±33.6%; injured-lax 20.4±13.6%. Conclusions Over one-third of players had previous USAI. Effect sizes indicate substantial within-group side-to-side differences and less substantial between-group differences. Across groups, some players had absolute-asymmetries that may elicit concern in ankle primary/secondary injury prevention and performance contexts.

Objectives Aim was to study the effect of monoski foot adjustment on kinematic and kinetic skiing parameters expressing sit skier’s technique. Design Independent variable was skier position with respect to bindings, acting on position of monoski foot sole clamp. Front (F), Mid (M) and Rear (R) settings changed with intervals of 20 mm. Course time, skiing speed, Ground Reaction Forces (GRFs) magnitude and point of application and damper stroke were dependent variables. Method A Paralympic monoski was equipped with a dynamometric binding plate measuring GRFs, roll and pitch moments. A Paralympic gold medalist (LW10-1) was involved. Skier trajectory and gates location were measured by a differential global navigation satellite system (GNSS) in steep and medium steep slope portions. The athlete performed two giant slalom runs for each foot setting the same day. Results GRFs, center of pressure (COP) and variations with foot settings were measured. Peaks values up to 3.36 times the total weight and damper speed of 675 mm/s in compression were found. Fastest runs, highest peak loads and best subjective ratings were recorded with F setting. COP mean values were influenced by foot adjustments. GRFs in left turns were 54% larger than in the right turns with F setting on steep slope. Conclusions The monoski foot adjustment influenced kinematic and kinetic skiing, with F setting showing best results. A skier asymmetric behavior between right and left turning was discovered. Findings can support the design of monoskis for a wider dissemination of Paralympic alpine sit skiing.

It remains unknown how biomechanics change in posterior lateral knee using different fixation techniques in lateral meniscal allograft transplantation (MAT)during simulated toe-touch partial weight-bearing. This study aimed tocompare the biomechanical effects on posterior knee between bridgeand bone plug fixation in lateral MAT.Intact knee, bone bridge fixation, and bone plug fixation were tested with 500 N of axial load during knee flexion at 0°, 30°, and 60°, which simulated toe-touch partial weight-bearing. Contact area and peak pressure were assessed on posterior knee and the shift of peak pressure position were measured.On the posterior lateral compartment, the contact mechanics of bone bridge fixation were similar to those of the intact knee (allP-values 0.05), but its peak pressure was higher than that of intact knee at 60° (P = 0.002). For bone plug fixation, the contact area of the posterior lateral knee was significantly lower than those of intact knee and bone bridge fixation at 30° and 60° (allP-values 0.05). The peak pressure of the posterior lateral knee was higher than that of the intact knee at all flexions and higher than that of bone bridge fixation at 30° and 60° (allP-values 0.05). The peak pressure position of bone plug fixation shifted more laterally and posteriorly compared with intact knee and bone bridge fixation during knee flexion.Bone bridges could maintain posterior knee biomechanics better than bone plug fixation during knee bending during partial weight-bearing.

High resolution peripheral quantitative computed tomography (HR-pQCT) was designed to study bone mineral density (BMD) and microarchitecture in peripheral sites at the distal radius and tibia. With the introduction of the second generation HR-pQCT scanner (XtremeCT II, Scanco Medical) that has a larger, longer gantry it is now possible to study the human knee in vivo using HR-pQCT. Previous validation of HR-pQCT measurements at the distal radius and tibia against micro-CT is not representative of the knee because the increased cross-sectional area, greater amount of soft tissue surrounding the scan region, and different imaging protocol result in potentially increased beam hardening effects and photon scatter and different signal-to-noise ratio. The objective of this study is to determine the accuracy of density and microarchitecture measurements in the human knee measured by HR-pQCT using an in vivo protocol. Twelve fresh-frozen cadaver knees were imaged using in vivo HR-pQCT (60.7 µm) protocol. Subsequentially, distal femurs were extracted and imaged using a higher resolution (30.3 µm) ex vivo protocol, replicating micro-CT imaging. Scans were registered so that agreement of density and bone microarchitecture measurements could be determined using linear regression and Bland-Altman plots. All density and microarchitecture outcomes were highly correlated between the 2 protocols (R2 > 0.89) albeit with statistically significant differences between absolute measures based on paired t tests. All parameters showed accuracy between 4.5% and 8.7%, and errors were highly systematic, particularly for trabecular BMD and trabecular thickness (R2 > 0.93). We found that BMD and microarchitecture measurements in the distal femur obtained using an in vivo HR-pQCT knee protocol contained systematic errors, and accurately represented measurements obtained using a micro-CT equivalent imaging protocol. This work establishes the validity and limitations of using HR-pQCT to study the BMD and microarchitecture of human knees in future clinical studies.

Acetabular fractures in the elderly are challenging. Management is complicated by patients' poor physiological status and osteoporotic bone. Analysis of the management of these patients must be separated from the treatment of younger patients. Conservative management continues to have a role in patients who sustain fractures that are non-displaced and are considered stable with weight bearing mobilisation, and in those patients considered too medically frail to undergo surgical intervention. The mainstay of current surgical intervention is open reduction and internal fixation (ORIF) and variations of ORIF and total hip arthroplasty (THA), or fix and replace. Fix and replace is being increasingly favoured in those patients who display poor prognostic factors for long term joint survival after ORIF. Percutaneous fixation has the theoretical benefits of minimally invasive surgery and the potential to make any subsequent THA less complicated. However, it requires specialised fluoroscopic skills and is not suitable for all fracture patterns. There are a number of developments being reported. The use of a reinforcement ring and THA in has been reported in a number of centres, as has the use of trabecular metal acetabular implants. A coned hemi pelvic prosthesis and THA has been described in our centre, with promising early results. The potential for 3D printing to improve preoperative planning and reduce intra-operative time is also being explored. The aim of this review is to provide a summary of the literature supporting current and future treatment methods, tips on reduction techniques and an overview of the treatment algorithm of these patients in our unit.

Background Although a variety of standardized measurements have been described to evaluate acetabular dysplasia, no single measurement is without limitations. We describe the Sourcil Index (SI), a novel measure of the weight-bearing surface of the acetabulum on anteroposterior pelvis films. The SI is the angle formed by the medial and lateral margins of the sourcil and the center of rotation of the femoral head. Methods Anteroposterior pelvis radiographs of skeletally mature patients from 2015 were reviewed. Studies with fractures or implants were excluded. Films were read by 2 orthopedic surgeons and a radiologist 3 times each, 8 weeks apart. The SI, Sharp's Angle (SA), and lateral center edge angle (LCEA) were recorded. Pearson intraclass correlation coefficients with 95% confidence intervals were calculated. The SI was then compared to the SA and LCEA to preliminarily assess diagnostic accuracy. Results Five hundred thirty-five hips in 292 patients met inclusion. Intraobserver reliability is as follows: SI = 0.95 (0.93-0.98), LCEA = 0.89 (0.82 -0.96), and SA = 0.90 (0.85-0.96). Interobserver reliability is as follows: SI = 0.90 (0.84-0.94), SA = 0.78 (0.64-0.86), and LCEA = 0.73 (0.56-0.82). There were 51 dysplastic hips within this cohort. Conclusion The SI is a reproducible measurement on plain radiographs. The SI is a two-dimensional representation of the size of the weight-bearing surface of the acetabulum and could provide an estimation of joint contact pressures. Used with existing measures, the SI may provide a more nuanced understanding of acetabular morphology.

Background An early postoperative mobilisation shows beneficial effects in terms of complications and mobilisation scores in older adult proximal femur fracture patients. An adequate load-bearing capacity of the operated extremity is essential for early mobilisation. We hypothesize that cement augmentation of the Proximal Femoral Nail antirotation (PFNA) leads to a higher load capacity during postoperative mobilisation compared to a non-cemented PFNA. Methods Forty-nine orthogeriatric patients with pertrochanteric fractures were enrolled consecutively in a maximum care hospital in a pre–post study design (level of evidence 2). A study group of 25 patients received nailing (PFNA) with additional cement augmentation (CA group), whereas the control group of 24 patients received the same fracture fixation without cement augmentation (NCA Group). All patients participated in a gait analysis using an insole force sensor to measure the loading rate (loadsol®, Novel, Munich, Germany) on the fifth postoperative day. Results The NCA group showed a mean age of 75,88 years (SD ± 9.62), the CA a mean age of 81,44 years (SD ± 7.77). The most common fracture type was a pertrochanteric fracture in both groups (NCA: n=20, CA: n=21) Both groups showed no differences with regards to the ASA (NCA: 2.67; CA: 2.68) score and the postoperative Parker Mobility Score (NCA: 2.67; CA: 2.68). Patients who received cement augmentation showed a significant (p=0.004) higher loading rate in the postoperative gait analysis. The CA group showed a loading rate of 58.12% (SD ± 14.50) compared to the uncemented PFNA group with 43.90% (SD ± 18.34). Conclusions Cement augmentation in elderly patients with a proximal femur fracture increased the early postoperative loading rate. Especially in frail patients with poor bone quality cement augmentation should therefore be considered to enhance early mobilisation with full weight bearing in order to reduce complications and improve survival.

Summary Objective The objectives of this study were: first, to compare solute uptake driven by sliding to cyclic uniaxial compression. And secondly, to evaluate the role of the superficial region on passive diffusion to determine if mechanical action is merely overcoming the low permeability of the superficial region or exceeding equilibrium capacity of the tissue. Design Tests were performed on osteochondral plugs under two types of conditions: cyclic loading (sliding vs axial compression) and unloaded passive diffusion (intact vs superficial zone removed). The articular surfaces were exposed to a fluorescent bath and uptake was quantified from the surface to the subchondral bone using fluorescent microscopy. Primary outcome measures were total mass transfer, mass transfer rate, and surface partition factor. Results Mass transfer was 2.1-fold higher at 0.5 h for sliding compared to uniaxial compression (p = 0.004). This increased to 4.4-fold at 2 h (p = 0.002). Solute transport for both loading conditions at 2 h had reached or exceeded intact passive diffusion at 12 h. Total mass transport and mass transport per hour was higher in samples without the superficial region compared to intact samples at equilibrium. Rate of mass transfer was not declining for samples subject to sliding indicating solute uptake induced by sliding would exceed passive tissue capacity. Conclusions These results are the first to quantify solute uptake between two components of joint articulation. The study demonstrates that sliding is a larger driver of solute transport compared to cyclic uniaxial compression. This has implications for cell nutrition, tissue engineering and biochemical signaling.

An external fixator is a promising medical device that could provide optimum stability and reduce the rate of complications in treating bone fracture during intervention period. It is noted that the biomechanics behaviour of device can be altered by introducing more features such as material suitability and additional components. Therefore, this study was conducted via finite element method to investigate the effects of additional hollow cylinder coated with external fixator screws in treating Type III pilon fracture. Finite element models which have been validated with experimental data were used to simulate stresses at the pin-bone interface and relative micromovement at interfragmentary fractures during swing (70 N load) and stance phases (350 N load). All bones and external fixators were assigned with isotropic material properties while the cartilages were simulated with hyper-elastic. For the hollow cylinder, polyethylene was assigned due to its properties which are equivalent to the bone. From the results, it is found that stresses at the pin-bone interface for the coated screws were reduced to 54% as compared to the conventional fixator. For the micromovement, there was no difference between both models, whereby the value was 0.03 mm. The results supported previously published literature, in which high stresses are unavoidable at the interface, fortunately, those stresses did not exceed the ultimate strength of bone, which is safe for treating patients. In conclusion, if patients are allowed to bear weight bearing, the external fixator with coated screws is a more favourable option to be fixed into the bone to avoid complications at the interface.

The sagittal plane relationship of the hindfoot and midfoot joints is a primary determinant of proper alignment in flatfoot reconstructive surgery as assessed both clinically and on postoperative weightbearing (WB) lateral radiographs. The traditional approach to intraoperative radiographic imaging allows for accurate assessment of fixation placement but only a crude evaluation of final sagittal plane alignment. Surgeons employ various methods in an attempt to load the foot during lateral imaging. Skepticism exists regarding the ability of simulated WB fluoroscopy to predict the final outcome, and evidence is lacking to support this practice. A retrospective investigation was performed assessing the correlation of Meary's angle, calcaneal inclination angle, and calcaneal-1st metatarsal angle as demonstrated on intraoperative simulated WB lateral foot imaging to 10- week postoperative full WB lateral radiographs. A consistent simulated WB imaging protocol was used with 46 consecutive cases of flatfoot reconstruction in this analysis of secular trends. The average change in Meary's angle between intraoperative simulated WB and postoperative full WB was -1.09° with 89% of cases within ±5°. The average change in calcaneal–1st metatarsal angle between intraoperative simulated WB and full WB was -2.61° with 85% of cases within ±5°. The average change in calcaneal inclination angle between intraoperative simulated WB and full WB was -2.62° with 88% of cases within ±5°. These findings confirm the clinical utility of intraoperative simulated WB lateral imaging as a useful tool in predicting the postoperative sagittal plane alignment of the midfoot and rearfoot in patients undergoing flatfoot reconstructive surgery.

Introduction Interprosthetic femoral fractures (IFF) are rare but increasing with an ageing population. Operative management is challenging and there is currently a paucity of outcome data in literature. The purpose of this study was to evaluate outcomes of IFFs managed with modern distal femoral locking plates, in a larger sample size than previously published. Method This retrospective study reviewed 49 closed IFFs in 48 patients at a major trauma center from 2009 to 2019 occurring between previous total hip arthroplasty (n=38), hemi hip arthroplasty (n=3), dynamic hip screw (n=6) or cephalomedullary nail (n=2) and total knee arthroplasty. They were managed with Minimally Invasive Plate Osteosynthesis (MIPO) employing modern biological fixation techniques and stabilised with VA-LCP Condylar (Synthes; n=28) or Peri-Loc (SN n=21) plate. Clinical and radiographic outcomes were measured. Results The majority of fractures were in female patients (80%), who were elderly (average 83 years), and comorbid (55% ASA grade 3 or 4). Most fractures were Pires type IIA and OTA/AO type 33A. Average plate spanning femur was 16 holes, with average working length of 6 holes. 86% had unrestricted weight bearing immediately post operatively. 31 fractures reached radiological (n=25) or clinical (n=6) union. 13 patients died with 2 lost to follow up. There were 3 non-unions, with implant failure occurring before 4 months in all 3. We present a union rate of 91% (n=31/34). Conclusion IFFs are occurring with increasing frequency in a frail elderly population. In patients with IFFs, MIPO and biological fixation techniques using modern distal femoral locking plates can achieve high rate of union when combined with immediate unrestricted weight bearing postoperatively.

Introduction Open tibial shaft fractures present a challenge to the orthopedic surgeon, because they are common, have a high rate of complications and still have a controversial treatment. As a result of the high incidence of these fractures, the need of a definitive treatment and the unavailability of the intramedullary nail or a well-trained team, we developed this study to compare the effectiveness of the bridge-plating (BP) with the unreamed intramedullary nail (UIMN) in the treatment of open tibial shaft fractures. Materials and methods Eighty patients were included in a prospective, consecutive and random way and then randomized in two groups of treatment: unreamed intramedullary nail and bridge-plating. The primary outcomes were the reoperation rate and the Johner-Wruhs functional criteria. Secondary outcomes were complication rates, partial and total weight bearing time and bone consolidation time. We verified the existence of normality in the quantitative variables for the outcomes using the Kolmogorov-Smirnov test. The Chi-Square test was utilized to compare the methods according to the relative frequencies and the comparison between the methods regarding the average of the quantitative variables was done through the T-Student test. Results Both the reoperation rates and the functional criteria of Johner-Wruhs showed no difference between the two groups. The exposure time and the total surgical time were longer in the UIMN group, however the consolidation time, partial weight bearing time and total weight bearing time did not show significant difference. A significant difference was found between the groups in the implant failure rate, in favor of UIMN, the angular malalignment was another secundary outcome that showed a non significant difference in favor of UIMN. Conclusions We concluded that both methods were effective for the treatment of open tibia shaft fractures, however, the implant failure rate was higher in the bridge plate group.

Background The reverse sural artery flap (RSAF) is widely used to reconstruct foot and ankle defects. Although it is commonly used in a nonsensate type, there has been controversy as to whether it provides sufficient stability and durability when applied to weight-bearing heels. The aim of this study was to evaluate patient outcomes after weight-bearing heel coverage using a nonsensate RSAF. Methods Twenty-three patients who underwent reconstruction surgery of the weight-bearing heel with RSAF from 2004 to 2018 in a tertiary hospital were retrospectively reviewed. All surgeries were performed without a sensate procedure. The patients’ experience of pressure sore on the flap area and the ability to use normal footwear were investigated. Light touch, Semmes-Weinstein test (SWT), and two-point discrimination tests were assessed, along with postoperative wound complications. Results Heel damage etiologies included malignant tumors in 14 (61%), trauma-related in 7 (30%) and diabetic ulcers in 2 (9%) patients. Patient mean age was 58 years (range, 18–93 years) and the mean follow-up period was 57 months (range, 12–185 months). The mean size of the flap was 64.1 cm2 (range, 20–169 cm2). All flaps healed without major complications. All returned to daily living activities and 20 (86%) patients were able to use normal footwear. Of the 11 patients who had available measurement records, 8 (73%) showed a light touch sense. The mean SWT value was 4.31 (range, 3.61– 4.56). Two-point discrimination was not observed in any of the patients. Two patients had experienced superficial ulcers on the flap within a one-year postoperative period, which spontaneously healed and did not recur. No full-thickness ulcers were observed during the follow-up period. Conclusions The results of this study suggest that patients who underwent nonsensate RSAF for the reconstruction of the heel could expect to maintain the property for stable weight-bearing without pressure sore.

One-in-five people suffer from chronic low back pain (LBP). The incidence of this disease has doubled since 1950s and affects not only the elderly, but also the young population. However, the mechanism of LBP is still unknown. A possible location where the LBP may develop is the facet joint and it has been revealed that the intervertebral disc (IVD) nucleotomy may be a trigger for LBP. The aim of the present study was to investigate the influence of IVD nucleotomy on the load sharing in the spinal facet joint under the loading scenarios of different postures. Finite element (FE) models of the intact and nucleotomised L4 – L5 spinal segments were generated from the clinical CT images. Seven human postures, including upright, 5° extension, 5° flexion, ± 6° lateral bending and ± 2° axial rotation, were simulated. The resultant forces in the fact joint were compared between the intact and the nucleotomised cases. It was revealed that the IVD nucleotomy significantly increased the forces in the facet joints under the loading scenarios of upright, 5° extension and 5° flexion. The IVD nucleotomy increased the force in the ipsilateral facet joint but decreased the force on the contralateral side under the loading scenarios of ± 2° axial rotation. However, the IVD nucleotomy made little influence on the resultant forces in both facet joints in the postures of ± 6° lateral bending. In conclusion, the IVD nucleotomy can cause an increase in the overall force in the facet joint, and thus may serve as a possible explanation for the LBP and a main contributing factor for the pain complaints.

Objectives The purpose of this multicenter study was to assess the differences in the rates of implant failure and bone union by X-ray examination, and walking ability between an early weight-bearing group (EWB) and a non-weight-bearing group (NWB) following treatment with intramedullary nailing (IMN) for tibial shaft fractures with a propensity score-matching method. Material and Methods We collected data from 336 patients with tibia fractures that were treated surgically. We excluded patients lost to follow-up and polytrauma patients. Finally, 263 patients were included who were divided into two groups, the early weight-bearing (EWB) group, in which partial weight-bearing walking within four weeks was encouraged, and a non-weight-bearing (NWB) group, in which no weight bearing was allowed for more than four weeks. To adjust for baseline differences between groups, a propensity score algorithm was used to match the EWB group with the NWB group in a 1:1 ratio of 75 cases each. After matching, we compared the rate of implant failure, the rate of bone union at six months and one year after surgery, and walking ability at the last follow-up between the two groups. Result Implant failure occurred in 0 of 75 patients in the EWB group vs. 1 of 75 in the NWB group (P = 1.0). Delayed bone union at six months occurred in 20 of 75 (26%) vs. 13 of 75 (17%) patients, and that at one year occurred in 5 of 75 (6.7%) vs. 3 of 75 (4%) patients. The median New Mobility Score was 9 (4–9) vs. 9 (0–9) points. Conclusions There were no statistically significant differences in the rate of implant failure, the rates of the bone union at six months and one year after surgery, and walking ability between the EWB group and NWB group. We suggest that instruction in early weight-bearing after IMN nailing for tibial shaft fracture may not be harmful.

Objectives To compare re-rupture rate, functional and quality-of-life outcomes, return to sports and work, complications, and resource use in patients treated non-surgically with different rehabilitation regimens for Achilles tendon rupture. Design Systematic review and meta-analysis. Methods We performed a systematic literature search in PubMed, Embase, Scopus and the Cochrane Library through May 2020 to identify randomized controlled trials (RCTs) that included patients treated non-surgically for Achilles tendon rupture. All analyses were stratified according to rehabilitation protocols. Results Eight RCTs with a total of 978 patients were included. There was no significant difference about re-rupture rate (P = 0.38), return to sports (P = 0.85) and work (P = 0.33), functional outcome (P = 0.34), quality of life (P = 0.50), and complication rate (P = 0.29) between early weight bearing with functional ankle motion and traditional ankle immobilisation with non-weight bearing. Similarly, no significant difference in re-rupture rate (P = 0.88), return to sports (P = 0.45) and work (P = 0.20), functional outcome (P = 0.26), and complication rate (P = 0.49) was seen between ankle immobilisation with non-weight bearing and early weight bearing without functional ankle motion. Conclusions Traditional ankle immobilisation with non-weight bearing was not found to be superior to early weight bearing with or without functional ankle motion for patients treated non-surgically for Achilles tendon rupture. Clinicians may consider early weight bearing in functional brace as a safe and cost-effective alternative to non-weight bearing with plaster casting.

Aim of study To report outcomes of tendo-Achilles lengthening (TAL) followed by weight-bearing total contact cast (TCC) in the out-patient setting for patients presented with midfoot Charcot neuroarthropathy (CN) and, develop a new classification system for midfoot CN based on this experience. Patient and methods Published evidence suggests that tight Achilles-gastrocnemius-soleus complex is the deforming force in the initiation and progression of midfoot CN and TAL has shown to improve the range of ankle dorsiflexion and reduction of midfoot plantar pressures. We utilised this technique in the out-patient setting followed by weight-bearing TCC for all new patients who presented with a diagnosis of midfoot CN from February 2018. We report their outcomes after a 12 months follow-up and propose a new classification system based on the clinical and radiographic parameters. Results TAL followed by weight-bearing TCC was performed in 33 feet. In 30 feet, the disease progression either stopped or receded to a lower stage on the new classification system. The procedure was well tolerated by patients in an out-patient setting and there were no reported complications such as wound healing, complete transaction of tendon or deep vein thrombosis. At 12 months follow-up, 30 of 33 pts returned to their pre-procedure level of mobilisation with their usual walking aids or customised shoes. The inter-observer agreement was k = 0.86 for read 1 and k = 0.96 for read 2; and intra-observer agreement ranged from 0.93 to 1.00 for the double read indicating excellent inter-observer and intra-observer agreement. Conclusion TAL followed by weight-bearing TCC is a safe and well tolerated procedure when performed in an out-patient setting. The Charcot disease of the midfoot slowed in the early stages of midfoot CN and in some cases, receded. The new classification system is easy to use, reliable, reproducible and sensitive enough to detect changes in the disease progression.

Hallux valgus is a complex deformity with a variety of techniques described for correction. A biplanar plating system for triplanar correction system has been developed to address both the translation and rotational component of the hallux valgus deformity and allow an accelerated weightbearing protocol. The purpose of this study was to determine the correction and complications using radiographic parameters and patient reported outcomes. We sought to determine prognostic factors for successful correction, including age, gender, and preoperative deformity. From the medical records, we collected preoperative data. Patient-reported outcomes were obtained using AOFAS Hallux Metatarsophalangeal-Interphalangeal score, FAAM, and SF-12 scores preoperatively and postoperatively. Imaging was reviewed at preoperative and postoperative visits to determine hallux valgus angle, intermetatarsal angle, and tibial sesamoid position. Fifty-seven procedures, in 55 patients, were performed. There were 7 complications and mean follow-up time was 45.7 weeks (+ 28.3 weeks). Age over 62.5 years were associated with an increased risk of complications (p = .018). Males had an increased rate of complications (71%) compared with females. Radiographic parameters were significantly improved from preoperative values at alltime points (p.05). Only the AOFAS Hallux Metatarsophalangeal-Interphalangeal score was statistically significant at 3, 6 and 12 months. We sought to determine the effectiveness of biplanar plating and triplanar correction procedure with early weightbearing. Over a 12 month follow-up period, our results showed significant improvement in deformity and maintained correction. AOFAS Hallux Metatarsophalangeal-Interphalangeal scores significantly improved from the preoperative to the postoperative state. Our results show a nonunion rate of 5.2%, which is comparable to prior studies.

Arthrodesis of the first tarsometatarsal joint (TMT1) reduces pathologic angles at the anatomic center of rotation of angulation and presents a substantial correction potential in 3 planes in the treatment of hallux abductovalgus. The optimal fixation method remains unclear since prevailing dorsomedial locking plates and/or compression screws depict elevated implant-associated complications. Medical records of 49 patients that underwent 53 TMT1 arthrodeses in hallux abductovalgus interventions were included. Median average visual analog scale scores decreased (p < .001) from 6.8 (range 4-10) to 2.7 (range 0-10), first intermetatarsal angles were reduced (p < .001) from 17.39° (range 12°-28°) to 7.16° (range 3°-12°), standing lateral first metatarsal angles improved (p < .001) from 21.66° (range 12°-29°) to 23.94° (range 14°-31°) and tibial sesamoid positions were plantarized (p < .001) from 6.02° (range 4°-7°) to 2.79° (range 1°-6°). Plantar plating allowed immediate weightbearing with transition to normal shoe gear at 6 weeks. Complications occurred in 6 (11.34%) feet including 1 (1.89%) nonunion, 1 (1.89%) delayed union, 1 (1.89%) hallux varus, 1 (1.89%) incomplete recurrence, 1 (1.89%) minor dehiscence, and 1 (1.89%) hardware irritation. Plantar locking plates combined with a dorsal compression screw presented a favorable tension-side implant location that closed the fusion site under load. This facilitated substantial reductions in complications, pathologic angles, and pain.

There are several options for plate fixation of distal radius fractures. Volar plating has broad applicability and consistent outcomes, and thus is the most commonly used plate type. Dorsal plates are advantageous for specific fracture patterns, and can provide direct fracture reduction and buttressing, but may be prominent and can cause tendon irritation. Bridge plates offer an alternative to external fixation while avoiding the complications with prominent hardware, because they span highly comminuted fractures and can be used for immediate weight bearing; however, they require plate removal. Choice of plate fixation should depend on fracture type, patient factors, and surgeon experience.

Background The superiority of screw or suture button fixation for syndesmotic instability remains debatable. Our aim is to compare radiographic outcomes of screw and suture button fixation of syndesmotic instability using weight bearing CT scan (WBCT). Methods Twenty patients with fixation of unilateral syndesmotic instability were recruited and divided among two groups (screw = 10, suture button = 10). All patients had WBCT of both ankles ≥12 months postoperatively. Results In suture button group, injured side measurements were significantly different from normal side for syndesmotic area (P = 0.003), fibular rotation (P = 0.004), anterior difference (P = 0.025) and direct anterior difference (P = 0.035). In screw group, syndesmotic area was the only significantly different measurement (P = 0.006). Conclusion While both screw and suture button didn’t completely restore the syndesmotic area as compared to the contralateral uninjured ankle, external malrotation of the fibula was uniquely associated with suture button fixation. Level of Evidence III Retrospective Cohort Study

Titanium has been used in various biomedical applications; however, titanium exhibits poor wear resistance, and its bioinert surface slows osseointegration in vivo. In this study, directed energy deposition (DED)-based additive manufacturing (AM) was used to process hydroxyapatite (HA) reinforced Ti6Al4V (Ti64) composites to improve biocompatibility and wear resistance simultaneously. Electron micrographs of the composites revealed dense microstructures where HA is observed at the β-phase grain boundaries. Hardness was observed to increase by 57% and 71% for 2 and 3 wt.% HA in Ti64 composites, respectively. XRD analysis revealed no change in the present phases. Tribological studies revealed an increase in contact resistance due to in situ HA-based tribofilm formation, reduction in wear rate when testing in DMEM with a ZrO(2) counter wear ball

Background Motion axial system may affect contact stress of hinge knee prosthesis. However, it is unclear which axial system provides the better biomechanical effect. Therefore, the aim of this study was to compare the contact stress and stress distribution on the tibial insert and the bushing of hinge knee prostheses with a biaxial (BA) system and a spherical center axial (SA) system during a gait cycle. Methods Three-dimensional finite-element (FE) models of the prostheses with different motion systems were included. The comparisons between experimental tests and FE analyses were performed to verify the models. Dynamic implicit FE analyses were performed to investigate the peak contact stresses and stress distributions on the tibial insert and the bushing. Results The peak contact stresses on the tibial insert and the bushing of the BA prosthesis were higher than those of the SA prosthesis during most gait cycles. The contact time on the bushing is short in the SA prosthesis. The stress distributions on the superior surface of the tibial insert in the BA prosthesis were at the posterior side, but of the SA prosthesis were not fixed. Conclusion The SA prosthesis has a lower peak contact stress on tibial insert and bushing than the BA prosthesis; in addition, the SA prosthesis has a ‘self-adjustment’ mechanism which could disperse high stress on the tibial insert to decrease the risk of wear and damage. The comparison could help designers and surgeons to better understand the future design of rotating hinge knee prostheses which should be able to achieve multiaxial motion and complete weight bearing by the tibial condylar to transmit the axial force better.

The canine and feline carpus is a complex arrangement of bones, ligaments, and joint spaces that functions as a ginglymus joint to provide carpal flexion and extension. Given the demanding biomechanical demands on the carpus during weight bearing, a variety of region-specific pathology, often secondary to trauma, are reported. This review details carpal anatomy, biomechanical understandings, and current evidence surrounding carpal pathology and its management. Partial carpal arthrodesis and pancarpal arthrodesis outcomes are reviewed in detail.

Objectives To determine the effect of mobilization with movement (MWM) on pain, ankle mobility and function in patients with acute and sub-acute grade I and II inversion ankle sprain. Study design Randomized placebo controlled trial. Setting A general hospital. Subjects 32 adults with inversion ankle sprain. Main outcome measures The primary outcome was pain intensity on an 11 point Numeric Rating Scale (NRS) with higher score indicating greater pain intensity. Ankle disability identified by the Foot and Ankle Disability index (FADI) with higher score indicating lower disability, functional ankle dorsiflexion range, pressure pain threshold, and dynamic balance measured with the Y balance test were secondary outcomes. Results Thirty participants completed the study. At each follow-up point, significant differences were found between groups favouring those receiving MWM for all variables. Pain intensity showed a mean difference of 1.7 points (95% confidence interval, 1.4 to 2.1) and 0.9 points (95% confidence interval, 0.5 to 1.3) at one and six-months follow-up respectively. Benefits were also shown for FADI, ankle mobility, pressure pain threshold and balance. Conclusion This study provides preliminary data for the benefits of MWM for acute and sub-acute ankle sprain in terms of pain, ankle mobility, disability and balance.

Background The purpose of this study was to clarify the in vivo kinematics of a newly updated posterior-stabilised (PS) mobile-bearing total knee arthroplasty during high-flexion activities in weight-bearing (WB) and non-weight-bearing (NWB) conditions. The hypothesis was that the kinematics would differ between the WB and NWB conditions, and the kinematics would be affected by the WB condition. Methods The kinematics of 19 knees were investigated under fluoroscopy during squatting (WB) and active-assisted knee flexion (NWB) with two- and three-dimensional registration technique. Accordingly, the range of motion, anteroposterior (AP) translation of the medial and lateral contact points, axial rotation of the femoral component relative to the tibial component, and kinematic pathway were evaluated. Results There was no difference in the knee’s range of motion between the WB and NWB conditions. The medial AP translation of the femur did not differ in each flexion angle between WB and NWB conditions except for flexions of 70°. There was no difference in the lateral AP translation of the femur at all tested flexion angles between the WB and NWB conditions. The external femoral rotation and the medial pivot motion were observed throughout all flexion angles in WB conditions. The clinical relevance is that this implant could produce ideal medial AP stability and medial pivot motion. Conclusion The medial AP translation of the femur was stable for AP direction when it was in both WB and NWB conditions. In WB conditions, the medial pivot motion was observed throughout all flexion angles. Level of Evidence: III.

Foot and ankle instability can be seen both in acute and chronic settings, and isolating the diagnosis can be difficult. Imaging can contribute to the clinical presentation not only by identifying abnormal morphology of various supporting soft tissue structures but also by providing referring clinicians with a sense of how functionally incompetent those structures are by utilizing weight-bearing images and with comparison to the contralateral side. Loading the affected joint and visualizing changes in alignment provide clinicians with information regarding the severity of the abnormality and, therefore, how it should be managed.