Contact Area Pressure Research Articles

Risk factors for pressure injuries in individuals with spinal cord injuries who have sarcopenic obesity: A comparison of time-dependent changes in sacral region pressure between individuals with and without sarcopenic obesity

Objective To identify the risk factors for pressure injuries in individuals with spinal cord injuries (SCIs) who have sarcopenic obesity, comparing time-dependent changes in sacral region pressure in individuals with and without sarcopenic obesity. Design An experimental time series study. Setting Single-center hospital. Participants Twenty-five adult participants with subacute and chronic paraplegia who visited our rehabilitation center, Republic of Korea, between May 2021 and June 2022. Interventions Whole-body dual-energy X-ray absorptiometry was performed to diagnose sarcopenic obesity. After the participants were placed in the supine position for 1 hour, the average pressure (mmHg), peak pressure (mmHg), and total contact area (cm2) of the sacral region were measured using the pressure-mapping system. Results Compared with the non-sarcopenic obesity group, the sarcopenic obesity group showed significant before-and-after differences in peak pressure. Furthermore, the risk factors that were significantly associated with peak pressure in the sarcopenic obesity group were the American Spinal Injury Association Impairment Scale score and the fat mass index. Conclusion Among participants with SCIs, the risk of pressure injuries is higher in the sarcopenic obesity group than in the non-sarcopenic obesity group. Notably, the risk of pressure injuries increases in participants who have complete injury and an increased fat mass index, indicating the importance of close monitoring and more active management to prevent pressure injuries in this subpopulation.

Biomechanical analysis of load distribution in porcine hip joints at different acetabular coverages

BackgroundDevelopmental dysplasia of the hip causes secondary osteoarthritis. Finite element analysis suggests high hip joint contact pressure in patients with hip dysplasia and a reduction in contact pressure after periacetabular osteotomy. However, few biomechanical studies have examined the load distribution in the hip joint. This study aimed to investigate the biomechanical properties of load distribution in porcine hip joints at different acetabular coverages.MethodsSix porcine hip joints were analyzed using three models: 1) neutral coverage, 2) 15° under-coverage (defined as dysplasia model), and 3) 15° over-coverage created by varying the acetabular coverage. The load distribution was assessed using a pressure-mapping sensor system after applying a loading force of 100 N to the hip joint.ResultsIn the dysplasia model, the load was concentrated at the acetabular rim; in the neutral and over-coverage models, it was dispersed. The average contact pressure was significantly higher in the dysplasia model than in the neutral coverage model ([0.42 vs. 0.3 MPa]; p = 0.004). The contact area was significantly smaller in the dysplasia model than in the neutral coverage model ([250.7 vs. 345.0 mm2]; p = 0.004). No significant differences were observed in contact pressure or area between the neutral and over-coverage models.ConclusionsInsufficient acetabular coverage in the dysplasia model demonstrated higher contact pressure and smaller contact area than the neutral model. Conversely, the contact pressure and area in the over-coverage model did not differ significantly from those in the normal model. Therefore, surgeons should note that acetabular coverage overcorrection has limited effect; normalization is crucial during periacetabular osteotomy.

Comparison of in-shoe plantar pressure between Korean combat boots and running shoes

IntroductionCombat boots are special shoes designed for soldiers to wear during activities in rough terrain, such as long marches or military training. Combat boots have been known to cause high...

Radial and longitudinal meniscus tears show different gapping patterns under stance phase conditions.

Meniscal tearing can increase the contact pressure between the tibia and femur by causing gapping of torn meniscus tissue. The aim of this study was to quantify gapping behavior of radial and longitudinal tears and their impact on peak contact pressure and mean contact area. Twelve porcine knee joints underwent unicondylar, convertible osteotomy for exact tear application and consecutive suturing. Six tantalum marker beads were positioned along meniscus tears. The joints were preloaded with sinusoidal loading cycles ranging between 0 N and 350 N. Peak load was held constant and two synchronized Roentgen stereophotogrammetric analysis x-ray images were obtained to evaluate gapping, peak contact pressure and mean contact area in the native, torn and repaired states. There was no change in gapping or peak contact pressure in longitudinal tear. By contrast, the radial tear led to a significant gapping when compared to the native state, while the inside-out suture was able to restore gapping in parts of the meniscus. An increase in contact pressure after radial tear was detected, which was again normalized after suturing. The most important finding of the study is that longitudinal tears did not gap under pure axial loading, whereas radial tears tended to separate the tear interfaces.

A combined experimental and finite element analysis of the human elbow under loads of daily living

Elbow trauma is often accompanied by a loss of independence in daily self-care activities, negatively affecting patients’ quality of life. Finite element models can help gaining profound knowledge about native human joint mechanics, which is crucial to adequately restore joint functionality after severe injuries. Therefore, a finite element model of the elbow is required that includes both the radio-capitellar and ulno-trochlear joint and is subjected to loads realistic for activities of daily living. Since no such model has been published, we aim to fill this gap.For comparison, 8 intact cadaveric elbows were subjected to loads of up to 1000 N, after they were placed in an extended position. At each load step, the displacement of the proximal humerus relative to the distal base plate was measured with optical tracking markers and the joint pressure was measured with a pressure mapping sensor.Analogously, eight finite element models were created based on subject-specific CT scans of the corresponding elbow specimens. The CT scans were registered to the positions of tantalum beads in the experiment. The optically measured displacements were applied as boundary conditions.We demonstrated that the workflow can predict the experimental contact pressure distribution with a moderate correlation, the experimental peak pressures in the correct joints and the experimental stiffness with moderate to excellent correlation. The predictions of peak pressure magnitude, contact area and load share on the radius require improvement by precise representation of the cartilage geometry and soft tissues in the model, and proper initial contact in the experiment.

Changes in occlusion after orthognathic surgery: a systematic review and meta-analysis.

This study aims to systematically review and identify the changes of occlusion in patients after orthognathic surgery. The protocol was developed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P) and was registered to the International Prospective Register of Systematic Reviews (PROSPERO) under the registration number CRD42021253129. Studies included were Original articles only, Additionally, studies were included if the outcome of occlusal force was measured pre- and postoperatively and if occlusal forces resulted from a long follow-up of a minimum of 1year following orthognathic surgery using adequate measurement tools. Non-English articles, case reports, case series, and non-original articles, including systematic reviews and literature reviews, were excluded. The search strategy yielded a total of 978 articles. Of the 978 articles, 285 were duplicates. After reading the titles and abstracts, 649 articles were excluded, and full-text articles of the remaining 47 studies were reviewed independently by two authors for eligibility wherein 33 articles were excluded, because they did not meet the inclusion criteria. Finally, a total of 14 studies were processed for critical review. The occlusal force increased after orthognathic surgery, although not to the level of the control group; however, the maximal bite force remained unchanged. Immediately after orthognathic surgery, chewing and swallowing forces increased. Significant reductions in the postoperative occlusal contact pressure areas was also observed.

Influence of cantilever tip geometry and contact model on AFM elasticity measurement of cells.

We have measured the elastic properties of live cells by Atomic Force Microscope (AFM) using different tip geometries commonly used in AFM studies. Soft 4-sided pyramidal probes (spring constant = 12 mN/m and 30 mN/m, radius 20 nm), 3-sided pyramidal probes (spring constant = 100 mN/m, radius of curvature 65-75 nm), flat (circular) probes (spring constant = 63 mN/m, radius 290 nm) and spherical probes (spring constant = 43 mN/m, radius 5 μm) have been used. Cells (3T3 fibroblasts) having elastic moduli around 0.5 kPa were investigated. We found that cell measured stiffness shows a systematic dependence on tip geometry: the sharper the tip, the higher the average modulus values. We hypothesize that the blunter the tip, the larger the contact area over which the mechanical response is measured or averaged. If there are small-scale stiffer areas (like actin bundles) they will be easier to pick up by a sharp probe. This effect can be seen in the wider distribution of the histograms of the measured elastic moduli on cells. Furthermore, non-linear responses of cells may be present due to the high average pressures applied by sharp probes, which would lead to an overestimation of the Young's modulus. Pressure versus contact radius simulations for the different tip geometries for a 0.5 kPa sample suggested similar average pressure for Bio-MLCTs, PFQNM and cut tips, except spherical tips that showed much lower average pressure at the same 400 nm indentation. However, real data of the cells suggested different results. Using the same indentation depth (400 nm) PFQNM and Bio-MLCTs showed similar average pressure and it decreased for cut and spherical tips. The calculated contact area at 400 nm cell indentation, using the obtained apparent Young's modulus for each tip geometry, showed the following distribution: Bio-MLCTs < PFQNM < cut << spherical. In summary, tip geometry as well as average pressure and tip-sample contact area are important parameters to take into account when measuring mechanical properties of soft samples. The larger the tip radius, the larger the contact area that will lead to a more evenly distribution of the applied pressure.

Sacral interface pressure can be alleviated by repositioning with a small-angle change using an automated bed in patients with spinal cord injury

Aim of the studyThis study aimed to compare interface pressure and total contact area of the sacral region in different positions, including small-angle changes, in patients with spinal cord injury (SCI). Furthermore, we analyzed the clinical factors influencing pressure to identify the pressure injury (PI) high-risk group. Materials and methodsAn intervention was conducted for patients with paraplegia (n = 30) with SCI. In the first and second trials, interface pressure and total contact area of the sacral region were recorded from large- and small-angled positions using the automatic repositioning bed, which can change the angle of the back, lateral tilt, and knee. ResultsPositions with back raised ≥45° showed significantly higher pressure on the sacrum than most other positions. The pressure and contact area differences were statistically insignificant for combinations of small-angled changes <30°.Additionally, the duration of injury (β = 0.51, p = 0.010) and neurological level of injury (NLI) (β = −0.47, p = 0.020) were significant independent predictors of average pressure. Similarly, the duration of injury (β = 0.64, p = 0.001), the Korean version of the spinal cord independence measure-III (β = −0.52, p = 0.017), and body mass index (BMI; β = −0.34, p = 0.041) were significant independent predictors of peak pressure. ConclusionsFor repositioning, combinations of small-angle changes <30° effectively reduce pressure on the sacral region in patients with SCI. Lower BMI, longer duration of injury, lower functioning score, and NLI ≥ T7 are predictors of high sacral pressures, which increase the risk for PI. Therefore, patients with these predictors require strict management.

Modified Double-Pulley And Rip-Stop Suture Bridge Technique In Arthroscopic Rotator Cuff Repair

Numerous techniques have been formulated for increasing the tendon–bone contact area and for providing a better healing environment for the tendon in cases of rotator cuff tear. An ideal rotator cuff repair maximizes the tendon–bone interface and provides the rotator cuff with sufficient biomechanical strength for it to withstand a high load. In this article, we propose a technique with the advantages of both the double-pulley and the rip-stop suture-bridge techniques, which increases the pressurized contact area along the medial row, achieves higher failure loads than non-rip-stop techniques, and reduces tendon cut-through.

Diabot: Development of a Diabetic Foot Pressure Tracking Device

Foot-related problems are prevalent across the globe, and this issue is aggravated by the presence of diabetes mellitus. Diabetic-foot-related issues include extreme foot pain, plantar corns, and diabetic foot ulcers. To assess these conditions, accurate characterization of plantar pressure is required. In this work, an in-shoe, low-cost, and multi-material pressure measuring insole, based on a piezoresistive material, was developed. The device has a high number of sensors, and was tested on 25 healthy volunteers and 25 patients with different degrees of diabetes. The working range of the device was observed to be 5 kPa to 900 kPa, with an average hysteresis error of 3.25%. Plantar pressure was found to increase from healthy to diabetic volunteers, in terms of both standing and walking. In the case of the diabetic group, the-high pressure contact area was found to strongly and positively correlate (R2 = 0.78) with the peak plantar pressure. During the heel strike phase, the diabetic volunteers showed high plantar pressure on the medial heel region. In regard to the toe-off phase, the central forefoot was found to be a prevalent site for high plantar pressure across the diabetic volunteers. The developed device is expected not only to assist in the prediction of diabetic ulceration or re-ulceration, but also to provide strategies and suggestions for foot pressure alleviation and pain mitigation.

Static Foot Pressure and Percentage Contact Area of the Foot as an Assessment Tool for the Success of Anterior Cruciate Ligament Reconstruction: A Cross-sectional Study

Introduction: Anterior Cruciate Ligament (ACL) plays a vital role in gait balancing and lower limb kinematics. Any injury to the ACL leads to gait imbalance and alterations in foot pressure distribution. The stability and biomechanics of the lower limb after ACL Reconstruction (ACLR) can be measured through foot pressure analysis, gait analysis, and percentage contact area of the foot, among others. Aim: To evaluate the static foot pressure and percentage contact area of the foot in ACL deficient group, comparing it with the ACLR group and the normal healthy individual group. Materials and Methods: An analytical cross-sectional study was conducted at the Department of Sports Medicine, King George Medical University, Lucknow, Uttar Pradesh, India from March 10, 2021 to March 15, 2023. A total of 15 patients in each group (ACL injury, ACLR patients, and normal healthy individuals) were included in this study. Foot pressures (static) were recorded in all three groups using the BTS P-WALK system with BTS Biomedical software, which included high- density sensors and a plate size of 700 × 500 × 5 mm. Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) software version 26.0. Chi-square and linear regression tests were used to analyse the differences between the groups. Results: In the intragroup analysis, ACL deficient patients’ ipsilateral limbs showed lower foot pressure in the mid-foot (7±3.4), hind-foot (40.33±10.08), and whole foot pressure (110.19±34.7 Pascal (N/M2)) (p-value&gt;0.05) compared to normal healthy individuals (126.06±19.4 Pascal (N/M2) (p&gt;0.05) and ACLR (125.06±14.3 Pascal (N/M2)) (p-value&gt;0.05) groups, which suggested insignificant differences. The percentage contact area of the foot was significantly lower (43.15±3.4) (p-value&lt;0.001) compared to normal healthy individuals (49.82±0.84) and ACLR (49.02±0.91) groups. However, in intergroup comparisons, the differences in mid-foot, whole foot pressure, and percentage contact area of the foot were significant (p-value &lt;0.001) within the groups. Conclusion: Although there is a wide range of variation in the values of static foot pressure and percentage contact area of the foot in ACL deficient patients, after ACLR, these values become nearly similar to those of normal healthy individuals at around one year after ACLR.

Influência de sexo e idade na estrutura do pé e pressão plantar em adultos assintomáticos

Abstract The aim of the study was identify the influence of gender and age of healthy adults on the foot structure and the plantar pressure during gait. Sample comprising 608 women and men participants. To identify the structure of the foot, anthropometric measurements of both the total and the truncated length of the foot, the width of the forefoot, and the heights of the back and navicular were taken. Peak pressure and plantar contact area in three foot-masks (forefoot, middle foot, and hindfoot) were considered markers of plantar pressure. The data were analyzed by two-way variance analysis. No significant influence of age on the foot structure dimensions was identified; however, women presented measures equivalent to the five significantly smaller anthropometric markers. As for the peak plantar pressure, both males and females showed statistically similar values, but significant differences were observed for age. As to the plantar contact area, while age did not have significant influence, men showed significantly higher values in the three foot-masks. The findings suggest that gender influences the foot structure and the plantar contact area, while age influences the peak of plantar pressure.

Exploring in-shoe plantar pressure differences at the metatarsal pad position for patients with diabetes and toe deformities: A pilot study

Patients with diabetes are often prescribed insoles with metatarsal pads intended to prevent and offload forefoot ulcers. However, to our knowledge, the plantar pressures specifically at the metatarsal pad had not previously been researched. The aim of this study was therefore to explore plantar pressures at the metatarsal pad position by comparing three toe deformity groups, claw toe (CT)/hammer toe (HT) and hallux valgus (HV), with a control group (NONE). In-shoe plantar pressures were measured using F-ScanTM and a polygon region of interest at the metatarsal pad position was created. Mean peak pressure (MPP), pressure-time integral (PTI) and percentage foot-insole contact area at the metatarsal pad position (%CA) were analysed from 24 patients (48 feet) in the metatarsal pad area. No significant difference was found between the groups regarding MPP, PTI or contact area. For MPP, the highest value was found in CT/HT (140kPa ± 61) and the lowest in HV (112kPa ± 33). In PTI, the highest value was for CT/HT (2.0 Ns/cm2 ± 1.0) and the lowest for HV (1.3 Ns/cm2 ± 0.4). The %CA was highest in CT/HT/HV (95%) and lowest in NONE (70%). A new quantitative approach was presented, assessing the metatarsal pad pressure effect on its corresponding plantar area of the foot. Further studies are needed to identify the conditions in which a metatarsal pad affects different foot statuses with regard to plantar pressure.

Study on the Impact Damage Characteristics of Transplanting Seedlings Based on Pressure Distribution Measurement System

Collision is one of the main causes of mechanical damage to the seedling during transplanting. To reveal the impact damage characteristics of plug seedlings, the kinetics equations of seedling collision were established based on Hertz’s contact theory, and the kinematic characteristics, elastoplastic deformation, and collision damage during seedling collision were analyzed using high-speed photography. Using the Tekscan pressure distribution measurement system, the significant levels of various factors that affect impact peak force (IPF) and damage of seedling pot (DSP) were studied, the change rule of contact pressure distribution of seedlings under significant factors was measured, and a regression model between IPF and DSP was established. The results showed that collision material, drop height and seedling pot size had significant effects on IPF and DSP. The contact pressure area of different collision materials from large to small was soil block, steel, and ABS plastic. The contact pressure area of seedlings of different pot sizes was big, medium, and small in descending order. At a dropping height of 50~350 mm, a contact pressure &gt; 10 kPa accounted for the major contact pressure area, which is the main reason for collision damage of the seedling pot. Linear regression models between IPF and DSP under different factors were established, and the determination coefficients (R2) were 0.98 and 0.94, respectively. The results provided a theoretical basis for understanding the collision damage mechanism of the plug seedling and how to reduce damage during transplanting.

Static contact mechanism between serrated contact wheel and rail in rail grinding with abrasive belt

Rail grinding with abrasive belt essentially appears as the complex nonlinear contact interaction between contact wheel, abrasive belt, and rail surface to realize flexible and efficient rail grinding, and in the grinding process, the higher grinding efficiency can be achieved with a serrated contact wheel. However, the contact mechanism between serrated contact wheel and rail is obscure. In this paper, a parametric contact model between serrated contact wheel and rail is established by setting the non-structural (grinding pressure and rotation angle) and structural parameters (helix angle, cogging ratio, etc.) of the serrated contact wheel. Then, the finite element simulation of contact behaviors under the changing conditions of various parameters is carried out to reveal the influences of the above parameters on the maximum contact stress, contact area, and rubber layer indentation depth. On this basis of the extension of the traditional Hertz contact theory and the calculation of the geometric structures of serrated contact wheel and rail, the mathematical model of the contact area is obtained and the ellipsoidal pressure distribution area and the stress concentration area are calculated and combined together to obtain the contact area pressure distribution model. The contact static test platform was designed and the errors between the theoretical and experimental lengths of the long and short axes of the contact area under a rotation angle of 0° were respectively determined as 7.3 % and 9.9 %, thus verifying the correctness of the established mathematical model. In addition, the theoretical and experimental results of the same points on the characteristic lines of the pressure distribution were obtained separately for the comparison. The comparison results proved the correctness of the mathematical model of pressure distribution.

Contact Characteristics at Interface in Three-Body Contact Conditions with Rough Surfaces and Foreign Particles

Nanoparticles as lubricant additives under a certain average diameter and concentration may reduce wear, friction and scuffing damage. However, atmospheric dust particles affect not only human health but also the efficiency of components, and even cause component failures. Therefore, the contact characteristics at interfaces with foreign particles require careful investigation. In this work, a 3-body microcontact mechanics concept is used to analyze the effects of wear debris and foreign particles on real contact area, contact mode, asperity deformation type and separation at interface. The results show that the relationship profile between dimensionless real contact area (At*) and dimensionless normal contact load (Ft*) is wedge-shaped in a 3-body contact interface. Using surface-to-surface 2-body contact area as upper bound and surface-to-particle 3-body contact as lower bound, the 3-body hybrid contact situation is in between upper and lower bounds. As the dimensionless normal contact load increases, At* increases gradually as well. The order of contact mode is p-s contact, hybrid contact and then s-s contact. If the 3-body contact interface is in hybrid contact mode, the decrease in the hardness and average third body diameter will cause the At* to increase significantly at the same Ft*. Conversely, the separation and real contact area ratio of plastic deformation decrease gradually. The turning point of contact area (TPCA) occurs when the contact mode is within hybrid contact mode and the ratio of average third body diameter to the composite equivalent surface RMS roughness is about 50–70% for foreign particles and wear debris. When the Ft* is slightly larger than Ftpca*, the third body and surface share the total interface load approximately equally which will help reduce the real contact pressure and plastic contact area to improve surface performance.

Rabbit hindlimb kinematics and ground contact kinetics during the stance phase of gait.

Though the rabbit is a common animal model in musculoskeletal research, there are very limited data reported on healthy rabbit biomechanics. Our objective was to quantify the normative hindlimb biomechanics (kinematics and kinetics) of six New Zealand White rabbits (three male, three female) during the stance phase of gait. We measured biomechanics by synchronously recording sagittal plane motion and ground contact pressure using a video camera and pressure-sensitive mat, respectively. Both foot angle (i.e., angle between foot and ground) and ankle angle curves were unimodal. The maximum ankle dorsiflexion angle was 66.4 ± 13.4° (mean ± standard deviation across rabbits) and occurred at 38% stance, while the maximum ankle plantarflexion angle was 137.2 ± 4.8° at toe-off (neutral ankle angle = 90 degrees). Minimum and maximum foot angles were 17.2 ± 6.3° at 10% stance and 123.3 ± 3.6° at toe-off, respectively. The maximum peak plantar pressure and plantar contact area were 21.7 ± 4.6% BW/cm2 and 7.4 ± 0.8 cm2 respectively. The maximum net vertical ground reaction force and vertical impulse, averaged across rabbits, were 44.0 ± 10.6% BW and 10.9 ± 3.7% BW∙s, respectively. Stance duration (0.40 ± 0.15 s) was statistically significantly correlated (p < 0.05) with vertical impulse (Spearman’s ρ = 0.76), minimum foot angle (ρ = −0.58), plantar contact length (ρ = 0.52), maximum foot angle (ρ = 0.41), and minimum foot angle (ρ = −0.30). Our study confirmed that rabbits exhibit a digitigrade gait pattern during locomotion. Future studies can reference our data to quantify the extent to which clinical interventions affect rabbit biomechanics.

Discharging the medial knee compartment: comparison of pressure distribution and kinematic shifting after implantation of an extra-capsular absorber system (ATLAS) and open-wedge high tibial osteotomy—a biomechanical in vitro analysis

PurposeYoung and active patients suffering early degenerative changes of the medial compartment with an underlying straight-leg axis do face a therapeutical gap as unloading of the medial compartment cannot be achieved by high tibial osteotomy. Extracapsular absorbing implants were developed to close this existing therapeutical gap. Purpose of the present cadaveric biomechanical study was to compare the unloading effect of the knee joint after implantation of an extra-articular absorber system (ATLAS) in comparison to open-wedge high tibial osteotomy (OW-HTO) under physiological conditions. The hypothesis of the study was that implantation of an extra-capsular absorber results in an unloading effect comparable to the one achievable with OW-HTO.MethodsEight fresh-frozen cadaveric knees were tested under isokinetic flexion–extension motions and physiological loading using a biomechanical knee simulator. Tibiofemoral area contact and peak contact pressures were measured using pressure-sensitive film in the untreated medial compartment. The tibiofemoral superior–inferior, latero-medial translation and varus/valgus rotation were measured with a 3D tracking system Polaris. Pressures and kinematics changes were measured after native testing, ATLAS System implantation and OW-HTO (5° and 10° correction angles) performed with an angular stable internal fixator (TomoFix).ResultsThe absorber device decreased the pressure in the medial compartment near full extension moments. Implantation of the ATLAS absorbing system according to the manufacturers’ instruction did not result in a significant unloading effect. Deviating from the surgery manual provided by the manufacturer the implantation of a larger spring size while applying varus stress before releasing the absorber resulted in a significant pressure diminution. Contact pressure decreased significantly Δ0.20 ± 0.04 MPa p = 0.044. Performing the OW-HTO in 5° correction angle resulted in significant decreased contact pressure (Δ0.25 ± 0.10 MPa, p = 0.0036) and peak contact pressure (Δ0.39 ± 0.38 MPa, p = 0.029) compared with the native test cycle. With a 10° correction angle, OW-HTO significantly decreased area contact pressure by Δ0.32 ± 0.09 MPa, p = 0.006 and peak contact pressure by Δ0.48 ± 0.12 MPa, p = 0.0654 compared to OW-HTO 5°. Surgical treatment did not result in kinematic changes regarding the superior–inferior translation of the medial joint section. A significant difference was observed for the translation towards the lateral compartment for the ATLAS system Δ1.31 ± 0.54 MPa p = 0.022 and the osteotomy Δ3.51 ± 0.92 MPa p = 0.001. Furthermore, significant shifting varus to valgus rotation of the treated knee joint was verified for HTO 5° about Δ2.97–3.69° and for HTO 10° Δ4.11–5.23° (pHTO 5 = 0.0012; pHTO 10 = 0.0007) over the entire extension cycle.ConclusionOW-HTO results in a significant unloading of the medial compartment. Implantation of an extra-capsular absorbing device did not result in a significant unloading until the implantation technique was applied against the manufacturer’s recommendation. While the clinical difficulty for young and active patients with straight-leg axis and early degenerative changes of the medial compartment persists further biomechanical research to develop sufficient unloading devices is required.

Arthroscopic Repair of Posterior Root Tears of the Lateral Meniscus with All-Suture Anchor

Meniscus root tears are increasingly being recognized and treated because of improved awareness and diagnostics. These injuries commonly occur in combination with knee ligament injuries. Untreated posterior meniscus root teats have been demonstrated to increase contact pressure and decrease contact area, ultimately leading to unfavorable joint loading and development of early osteoarthritis. Posterior lateral meniscus root tears (PLMRTs) also have been reported to increase anterior tibial translation and pivot shift in anterior cruciate ligament–deficient knees. Therefore, it is crucial to repair meniscal root tears when possible to restore knee joint loading and kinematics. Several techniques for repair of the PLMRT have been described. In this Technical Note, we describe our preferred technique for repair of PLMRT using an all-suture anchor. This technique is reproducible, does not need a tunnel, mitigates bungee effect of transtibial technique, and the anchor can easily be inserted on the footprint without a need for a guide.

Custom-made foot orthoses with and without heel plugs and their effect on plantar pressures during treadmill walking.

Foot orthoses have consistently demonstrated an improvement in pain scores for plantar fasciitis. The fabrication of custom-made foot orthoses (CFOs) can vary between clinicians and may include the use of different materials and casting techniques. This cross-sectional study's objective was to quantify plantar pressure for two CFOs, one with a heel plug (HP) and one without. Fourteen healthy participants (8 men and 6 women; 35.4 ± 7.7 years) were cast by the same practitioner. Both CFOs were made with the same materials and specifications, except for the HP orthosis, which replaced hard material under the heel with a softer blue PORON ® plug for added cushioning. Plantar pressures were recorded during treadmill walking for both devices in a running shoe. Average pressure, peak pressure, and pressure contact area were determined for three regions of the foot: hindfoot, midfoot, and forefoot. A paired samples t -test determined differences in each region ( P < 0.05). The HP orthosis reduced the overall means of average pressure, peak pressure, and pressure contact area in the hindfoot while tending to increase these measures in the midfoot and forefoot. The three measures showed statistically significant decreases in the hindfoot, whereas a statistically significant increase was seen in average and peak pressures in the midfoot ( P < 0.05). CFOs with HPs are more effective than regular CFOs in offloading plantar pressures in the hindfoot while increasing pressures in the midfoot. This is an important finding because offloading the hindfoot is critical in pathologies such as plantar fasciitis to decrease pain and increase function.