scholarly journals The Effect of Orthotics on Ankle and Subtalar Joint Orientation and Load Distribution Utilizing a Novel System to Simulate Weight Bearing in a Cadaveric Model

2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0001
Author(s):  
Naven Duggal ◽  
Ara Nazarian ◽  
Michael Nasr ◽  
Patrick Williamson ◽  
Stephen Okajima ◽  
...  
Keyword(s):  
Body Weight ◽  
Femoral Head ◽  
Lower Limb ◽  
Load Distribution ◽  
Subtalar Joint ◽  
Peak Pressure ◽  
Weight Bearing ◽  
Joint Orientation ◽  
Mean Pressure ◽  
Cadaveric Model

Category: Ankle, Basic Sciences/Biologics, Hindfoot, Biomechanics Introduction/Purpose: Orthotics are commonly prescribed by orthopaedic surgeons to address the hindfoot and midfoot deformity resulting from posterior tibial tendon dysfunction. The public however will often purchase over the counter orthotics for generalized complaints of foot pain that is not associated with any significant deformity or foot pathology. The mechanical axis of the lower limb may be altered in patients who use orthotics despite a normal foot alignment. We hypothesize that patients with normal alignment who use orthotics may adversely change ankle and subtalar joint orientation and load distribution. Methods: Five fresh frozen lower limb cadaveric specimens without known skeletal condition were used. The femoral head was potted with PMMA and TekScan pressure sensors were inserted into the ankle and subtalar joint. The specimens were placed on a custom jig, which allowed for load cell modulated loading of the leg; 75 lb load (half body weight) was applied at the femoral head while the foot was supported against a fixed plate keeping the ankle in neutral position. Testing was achieved by placing an orthotic under the medial half of the plantar talonavicular joint level. Mean pressure (MP), peak pressure (PP), contact area (CA), and center of force (COF) were measured in both the ankle and subtalar joints under three conditions; barefoot (BASE), with a 1.5 cm (ORT1) and 3 cm (ORT2) height orthotic. Each condition was tested three times per specimen. Displacement of COF was calculated relative to its location at baseline. Results: The MP, PP and CA showed a constant decrease from BASE to ORT1 and ORT2. Despite this relation, the only comparison that was significantly different was that between peak pressure values of the baseline and ORT2 conditions of the subtalar joint. The average displacement of COF from BASE was 0.14 mm and 0.42 mm medially, and 0.26 mm and 0.46 mm posteriorly at the ankle joint with ORT1 and ORT2 respectively. The average displacement of COF from BASE was 0.03 mm laterally and 0.08 mm posteriorly with ORT1, and 0.2 mm medially and 0.46 mm posteriorly with ORT2 at the subtalar joint. Conclusion: Foot deformities have an impact on the articular forces in the lower limb. Our results agree with previous studies about the role of foot deformity on the distribution of body weight forces and its consequences across the ankle and subtalar joint. Our novel study also demonstrates that orthotics and orthotics of varying sizes can change the mean pressure, peak pressure, contact area center of force in the ankle and subtalar joint. This study proves the feasibility of its design for studying intra-articular pressure changes in a lower limb cadaveric model with simulated weight bearing.

scholarly journals Effect of Achilles tendon lengthening on ankle and subtalar joint orientation and load distribution utilizing a novel cadaveric model to simulate weight bearing

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0021
Author(s):  
Naven Duggal ◽  
Patrick Williamson ◽  
Stephen Okajima ◽  
Peter Biggane ◽  
Michael Nasr ◽  
...  
Keyword(s):  
Achilles Tendon ◽  
Contact Area ◽  
Subtalar Joint ◽  
Peak Pressure ◽  
Weight Bearing ◽  
Joint Orientation ◽  
Ankle Arthroplasty ◽  
Tendon Lengthening ◽  
Mean Pressure ◽  
Achilles Tendon Lengthening

Category: Basic Sciences/Biologics Introduction/Purpose: Ankle arthroplasties are increasingly performed to address ankle arthritis. Patients with long standing ankle arthritis often present with an associated achilles tendon contracture. An open or percutaneous lengthening of the Achilles is commonly performed at the same time as the ankle arthroplasty to improve range of motion. Current ankle arthroplasty implants include mobile bearing and fixed bearing systems. Lengthening the achilles tendon improves dorsiflexion, however the effect of the lengthening on the ankle and subtalar joint is not well documented in the literature. Using a novel system to simulate weight bearing in a cadaveric model, we evaluated achilles tendon lengthening and its effect on ankle and subtalar joint orientation and load distribution. This may have potential implications to polyethylene implant longevity in total ankle arthroplasties. Methods: Five fresh frozen lower limb cadaveric specimens without known skeletal condition were used. The femoral head was potted with PMMA and TekScan pressure sensors were inserted into the ankle and subtalar joint. The specimens were placed on a custom jig, which allowed for load cell modulated loading of the leg; 75 lb load (half body weight)(4) was applied at the femoral head while the foot was supported against a fixed plate keeping the ankle in neutral position. Mean pressure (MP), peak pressure (PP), contact area (CA), and center of force (COF) were measured in both joints under two conditions; baseline (BASE), and following Achilles tendon release (TENDON) to simulate lengthening. Each condition was tested three times per specimen; the results were averaged per specimen and used for final analysis. Displacement of COF was calculated relative to its location at baseline. Results: The Mean Pressure (MP), Peak Pressure (PP) and Contact Area (CA) did not show a statistical difference in the ankle and subtalar joints between baseline (BASE) and TENDON (Achilles tendon release) conditions. (Table 1). Further, the displacement of the COF from the BASE to TENDON was 0.5 mm. In our model, the contracture of the muscle was not fully simulated. Further hindfoot kinetic studies with active achilles contracture may demonstrate a difference in contact forces in the ankle and subtalar joint as compared to normal. Conclusion: Ankle arthroplasty is becoming an effective treatment option for ankle joint arthritis. Our novel study demonstrates that Achilles tendon lengthening did not change the mean pressure, peak pressure, contact area center of force in the ankle and subtalar joint. This model provides validation for further studies evaluating tendon release and contact pressure changes in a cadaver with an implanted fixed bearing versus mobile bearing total ankle prosthesis. Difference in polyethylene wear may effect the longevity of ankle replacements. This study will provide clinicians additional information when evaluating the benefit/risks associated with lengthening the Achilles tendon for ankle arthroplasty patients.

Pressure Distribution in the Ankle and Subtalar Joint With Routine and Oversized Foot Orthoses

2018 ◽  
Vol 39 (8) ◽  
pp. 994-1000 ◽  
Author(s):  
Patrick Williamson ◽  
Aron Lechtig ◽  
Philip Hanna ◽  
Stephen Okajima ◽  
Peter Biggane ◽  
...  
Keyword(s):  
Contact Area ◽  
Lower Limb ◽  
Subtalar Joint ◽  
Peak Pressure ◽  
Weight Bearing ◽  
Force Distribution ◽  
Foot Orthoses ◽  
Pressure Mapping ◽  
Mean Pressure ◽  
Pressure Peak

Background: Foot orthoses are used to treat many disorders that affect the lower limb. These assistive devices have the potential to alter the forces, load distribution, and orientation within various joints in the foot and ankle. This study attempts to quantify the effects of orthoses on the intra-articular force distribution of the ankle and subtalar joint using a cadaveric testing jig to simulate weight bearing. Methods: Five lower-limb cadaveric specimens were placed on a custom jig, where a 334-N (75-lb) load was applied at the femoral head, and the foot was supported against a plate to simulate double-leg stance. Pressure-mapping sensors were inserted into the ankle and subtalar joint. Mean pressure, peak pressure, contact area, and center of force were measured in both the ankle and subtalar joints for barefoot and 2 medial foot orthosis conditions. The 2 orthosis conditions were performed using (1) a 1.5-cm-height wedge to simulate normal orthoses and (2) a 3-cm-height wedge to simulate oversized orthoses. Results: The contact area experienced in the subtalar joint significantly decreased during 3-cm orthotic posting of the medial arch, but neither orthosis had a significant effect on the spatial mean pressure or peak pressure experienced in either joint. Conclusion: The use of an oversized orthosis could lead to a decrease in the contact area and alterations in the distribution of pressure within the subtalar joint. Clinical Relevance: The use of inappropriate orthoses could negatively impact the force distribution in the lower limb.

scholarly journals Prediction of pathological fracture in patients with metastatic disease of the lower limb

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Emma L. Howard ◽  
Paul Cool ◽  
Gillian L. Cribb
Keyword(s):  
Body Weight ◽  
Metastatic Disease ◽  
Lower Limb ◽  
Prospective Observational Study ◽  
Pathological Fracture ◽  
Weight Bearing ◽  
Total Body Weight ◽  
Threshold Level ◽  
Total Body ◽  
Optimum Threshold

Abstract The aim of this study was to investigate if the risk of pathological fracture can be predicted with the proportion of body weight that can be put through the affected leg in patients with metastatic bone disease of the lower limb. A prospective observational study was conducted in patients with metastatic disease in the lower limb. Receiver Operator Characteristic curves were used to identify the optimum threshold level of single stance weight bearing to predict fracture and compared to the Mirels score. Patients who underwent surgery could weight bear significantly less than those who did not have surgical intervention. The optimum threshold to predict pathological fracture was 85% of total body weight. No patient below the threshold level of 85% single stance body weight sustained a pathological fracture. The use of single stance body weight can be a useful in conjunction with the Mirels score to predict pathological fracture. If less than 85% of total body weight can be put through the affected limb, the risk of fracture increases, and consideration of treatment is suggested.

Upper and lower limb loading during weight-bearing activity in children: reaction forces and influence of body weight

2017 ◽  
Vol 36 (14) ◽  
pp. 1640-1647 ◽  
Author(s):  
M. C. Erlandson ◽  
S. Hounjet ◽  
T. Treen ◽  
J. L. Lanovaz
Keyword(s):  
Body Weight ◽  
Lower Limb ◽  
Weight Bearing ◽  
Limb Loading ◽  
Reaction Forces

scholarly journals Comparison of lower limb segment forces during running on artificial turf and natural grass

2019 ◽  
Vol 6 ◽  
pp. 205566831983570 ◽  
Author(s):  
Shea McMurtry ◽  
Goeran Fiedler
Keyword(s):  
Body Weight ◽  
Lower Limb ◽  
Weight Bearing ◽  
Force Plate ◽  
The Body ◽  
Injury Incidence ◽  
Artificial Turf ◽  
Prosthetic Devices ◽  
Natural Grass ◽  
Realistic Force

Introduction: Artificial turf, soon after being introduced in the 1980s, became associated with an increased injury incidence in football players. While more recent generations of artificial turf have mitigated the problem, perception of the material is still widely negative. So, the decision to play the 2015 Fe'de'ration Internationale de Football Association Women s World Cup in Canada on artificial turf was met with vocal criticism by many players. One common approach is to assess injury incidence to quantify risk differences in playing surfaces. This, however, does not account for possible confounding variables or chronic injuries. Direct measurement of ground reaction forces is difficult because conventional multicamera-based motion capture and force plate equipment are limited in its use outside of dedicated laboratories. Methods: We describe a method of generating realistic force data by using miniature load cells that are installed directly into the weight-bearing structure of the body. Results: Pilot data show a significant (p<0.01) difference in peak forces on artificial turf (272% of body weight) and natural grass (229% of body weight). Discussion: Invasive surgical procedures were avoided by installing the load cell into the prosthesis of an athlete with lower limb loss. As modern prosthetic devices allow a close approximation of able-bodied kinematics and kinetics, such prosthesis-based data are transferable to a general population.

Pressure Distribution under Symptom-Free Feet during Barefoot Standing

Foot & Ankle ◽  
1987 ◽  
Vol 7 (5) ◽  
pp. 262-278 ◽  
Author(s):  
Peter R. Cavanagh ◽  
Mary M. Rodgers ◽  
Akira liboshi
Keyword(s):  
Body Weight ◽  
Pressure Distribution ◽  
Significant Relationship ◽  
Plantar Pressure ◽  
Load Distribution ◽  
Peak Pressure ◽  
Distribution Analysis ◽  
Pressure Distributions ◽  
Transverse Arch ◽  
Peak Pressures

The plantar pressure distributions for a large heterogeneous sample of feet (N = 107) were collected during barefoot standing using a capacitance mat. From these data, the function of the foot during standing was characterized. Peak pressures under the heel (139 kPa) were, on average, 2.6 times greater than forefoot pressures (53 kPa). Forefoot peak pressures were usually located under the second or third metatarsal heads. No significant relationship was found between body weight and the magnitude of peak pressure. The concepts of a transverse arch at the level of the metatarsal heads and a “tripod” theory of load distribution were not substantiated by this study. Load distribution analysis showed that the heel carried 60%, the midfoot 8%, and the forefoot 28% of the weightbearing load. The toes were only minimally involved in the weightbearing process. Examples of unusual distributions are shown; finally, a checklist is provided to aid the clinician in evaluating plantar pressure findings.

Improvement of the Soft Socket after Rotationplasty: A Single Case Study

2009 ◽  
Vol 33 (1) ◽  
pp. 10-16
Author(s):  
Martin Wessling ◽  
Mirko Aach ◽  
Jendrik Hardes ◽  
Elmar Janssen ◽  
Dieter Rosenbaum ◽  
...  
Keyword(s):  
Peak Pressure ◽  
Single Case ◽  
Weight Bearing ◽  
Functional Results ◽  
Activity Level ◽  
Pressure Measurements ◽  
Mean Pressure ◽  
The Mean ◽  
Weight Bearing Area

Rotationplasty is established as a functionally improving and partially ablative method of tumour surgery, but good clinical and functional results do not only depend on a successful surgery. Due to the changed biomechanical situation the activity level is limited by the weight bearing capacity of the rotated foot. Painful blisters and callosities may limit the use of the exo-prosthesis, because the skin is overstressed in the soft socket. A 28-year-old patient with a rotationplasty type A2 suffered from painful callosities of the rotated foot. Capacitive pressure measurements were performed as well as a gait analysis for kinematics and kinetic characteristics. Clinically a decrease of the callosities and a pain relieve was obvious and the patient learned skiing without prior knowledge. Biomechanically a decrease of the peak pressure (from 240.6–135.0 kPa) and the mean pressure (from 83.2–66.2 kPa), was observed with an increased weight bearing area. The study has shown that a modification of the heel bench can considerably improve pressure distribution. An increase of the load bearing area appears to enable the skin to compensate even intensive strain during athletic activities.

TO EVALUATE THE CHANGES IN HIP JOINT RELATED TO LOWER LIMB DOMINANCE AND ITS ASSOCIATION WITH HIP DISLOCATION

1969 ◽  
Vol 5 (1) ◽  
pp. 635-638
Author(s):  
NIAZ MOHAMMAD ◽  
MAQBOOL ILAHI ◽  
QAISAR ZAMAN
Keyword(s):  
Femoral Head ◽  
Hip Joint ◽  
Lower Limb ◽  
Weight Bearing ◽  
Hip Dislocation ◽  
Congenital Dislocation ◽  
Left Femur ◽  
Horizontal Diameter ◽  
The Mean ◽  
The Right

BACKGROUND: The stability of a joint depends on the arrangement of the articular surfaces. Thefailure of acetabulum to deepen along with associated relaxed capsule can be a causative factor leadingto congenital dislocation of hip in babies. The right traumatic hip dislocation is less uncommon ascompared to left side in adults.OBJECTIVE: To correlate the majority of right-footed population with the bony parameters of hipjoint bilaterally and to find out its association with left congenital and right acquired traumaticdislocation of hip.MATERIAL AND METHODS: As the right footed people are considerably more (90%) than the leftfooted and this study work was correlated with the bones collected from cadavers in Anatomydepartment of KGMC Peshawar from January 2014 to December 2014. We included 14 pairs of femurs,14 pairs of hip bones in this study to see the structural differences when dominant hip joint is comparedwith non-dominant hip joints. The measurements were performed with the help of vernier caliper.RESULTS: The mean horizontal diameter of right (dominant) and left acetabulum was 50.14±0.69 mmand 52.35±0.65mm. The mean horizontal depth of right and left acetabulum was 22.21±0.82mm and25.25±0.52mm. The horizontal diameter of right and left femur was 46.42±0.62mm and 43.85±01mm.The thickness of femoral head was 26.71±01mm on right (dominant) side but this thickness was29.17±01mm on left side.CONCLUSION: The left acetabulum was having a significant larger diameter in adult, allowing thesmaller left femoral head to fit snugly which can be correlated with the more common left congenitaldislocation hip. On the other hand, in adults, the left acetabulum is deeper, allowing the thicker left headof femur as an adjustment for weight bearing functionwhile the larger rightfemoral head fit into acomparatively shallow socket. This may be a factor to improve mobility at the cost of stability; as righttraumatic dislocationhip is less uncommon as compared to left side.KEY WORDS: Hip joint, Ball and socket joint. Dominant lower limb, Right footedness,Left footedness, Congenital dislocation hip, Traumatic dislocation hip.

scholarly journals Changes in the Mechanical Axis and Weight-Bearing Line of the Ankle After Varus Knee Correction

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0026
Author(s):  
Seung Yeol Lee ◽  
Soon-Sun Kwon ◽  
Kyoung Min Lee
Keyword(s):  
Femoral Head ◽  
Ankle Joint ◽  
Subtalar Joint ◽  
Mechanical Axis ◽  
Weight Bearing ◽  
Tibial Osteotomy ◽  
Varus Knee ◽  
Concentrated Load ◽  
Joint Axis ◽  
Tibial Plafond

Category: Ankle, Hindfoot Introduction/Purpose: Varus limb malalignment results in an imbalance of force transmission to the knee joint, resulting in a concentrated load in the medial compartment. A varus knee correction may affect the ankle and subtalar joint, because the weight-bearing load on the lower extremity extends from the hip to the foot. A previous study suggested that the true mechanical axis of the lower limb should be calculated with a line from the center of the femoral head to the lowest point of the calcaneus, not to the center of the tibial plafond. Therefore, we performed this study to evaluate changes in the mechanical axis and weight- bearing line of the ankle after varus knee correction. Methods: Patients with a varus knee who were followed-up after they had undergone high tibial osteotomy (HTO) or total knee replacement arthroplasty (TKA) at an age of >20 years, and who had undergone preoperative and postoperative scanogram were included in this study. The hip-knee-ankle (HKA) angle, mechanical axis, and weight-bearing line (line from the center of the femoral head to the lowest point of the calcaneus) were measured on the radiographs. The point at which the mechanical axis and weight-bearing line passed through the tibial plafond was the ankle joint axis point. The postoperative change in the ankle joint axis point on the mechanical axis and weight-bearing line according to the HKA angle correction was adjusted by multiple factors using a linear mixed model. Results: A total of 257 limbs from 198 patients were included in this study. The preoperative HKA was 7.3 ± 4.7° and corrected to 0.4 ± 3.8°. Although the ankle axis points on both axes moved laterally after HTO and TKA, the ankle joint axis of the weight- bearing line showed a significant larger lateral movement (22.5±35.7%) (Fig.) than that of the mechanical axis (15.7±16.0%) in terms of rate of change (p = 0.006). The ankle joint axis point on the weight-bearing line moved laterally by 0.9% per degree of postoperative HKA angle decrease (p < 0.001). The change in the ankle joint axis point on the mechanical axis was not statistically significant after HTO and TKA (p = 0.223). Conclusion: The mechanical axis and weight-bearing line of the ankle moved laterally after the varus knee correction. The ankle joint axis on the weight-bearing line moved laterally as the HKA angle decreased after the surgery, whereas the varus knee correction did not significantly affect the ankle joint axis on the mechanical axis. The varus knee correction might affect the subtalar joint as well as the ankle joint. Therefore, we believe that our findings warrant consideration in pre- and postoperative evaluations using the weight-bearing line of patients undergoing varus knee correction.

scholarly journals Ankle and Subtalar Joint Kinematics following Lateral Ligament Repair- Implications for Early Surgical Treatment

2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0002
Author(s):  
Kenneth Hunt ◽  
Nicholas Anderson ◽  
Judas Kelley ◽  
Richard Fuld ◽  
Todd Baldini
Keyword(s):  
Motion Capture ◽  
Contact Area ◽  
Subtalar Joint ◽  
Peak Pressure ◽  
Weight Bearing ◽  
Joint Kinematics ◽  
Ligament Repair ◽  
Tibiotalar Joint ◽  
Ligament Healing ◽  
The Impact

Category: Ankle Introduction/Purpose: The current trend for chronic lateral ankle instability treatment is direct repair of the ATFL and/or CFL by open or arthroscopic-assisted technique. There is recent evidence suggesting improved success with acute ligament repair following high grade ankle sprains as well as on the impact of CFL injury on ankle and subtalar biomechanics. However, the impact of acute repair on ankle and subtalar joint kinematics and biomechanics is not well understood. The purpose of this study was to determine the impact of repairing the ATFL alone compared to repairing both the ATFL and CFL, on restoration of ankle and subtalar joint kinematics. Methods: Ten matched pairs of fresh frozen human cadaveric ankles were dissected to expose intact ATFL and CFL. Ankles were mounted to an Instron at 20° plantar flexion and 15° of internal rotation. Each ankle was loaded to body weight and then inverted from 0 to 20° for three cycles; Peak pressure and contact area were recorded in the ankle joint using a calibrated Tekscan sensor system, and linear and rotational displacement of the talus and calcaneus relative to the ankle mortise was recorded using a three-dimensional motion capture system. Ankles then underwent sequential sectioning of ATFL and CFL and were randomly assigned to ATFL-only repair using two arthroscopic Broström all-soft anchors, or combined ATFL and CFL repair. Testing was repeated after repair. Results: Motion capture showed a significant increase in inversion angle of both the calcaneus and talus after release of each ligament. There was significantly more inversion in the subtalar joint than the tibiotalar joint with weight-bearing inversion. There was a significant increased medial shift of the calcaneus after CFL release. Neither ATFL alone nor combined ATFL/CFL repairs restored normal ankle joint inversion. Isolated ATFL repair restored inversion of subtalar joint nearing the intact state. We found no significant difference in peak pressure or contact area in the tibiotalar joint between the intact ankle and ATFL or combined repair. However, there was a 26% decrease in peak pressure following ATFL repair, and only an 11% decrease in peak pressure following ATFL/CFL repair compared to the uninjured ankle. Conclusion: The addition of CFL repair does not appear to provide significant improvement compared to ATFL repair alone in the immediate repair setting. Neither group demonstrated restoration of normal talus inversion with weight-bearing inversion testing, suggesting that acute repair, without a period of ligament healing, is not sufficient to resist a weight-bearing inversion moment. While the CFL plays an important role in normal ankle mechanics, this data supports the necessity for a protection period to allow sufficient ligament-healing before weight-bearing inversion stresses are applied following surgical repair.

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