Weight-bearing Conditions Research Articles

Effect of Weight Bearing Variations & Heel Height on Forefoot Width for Orthopaedic Imaging

Category:Basic Sciences/Biologics; Midfoot/ForefootIntroduction/Purpose:The biomechanics of a foot when weight bearing change significantly due to the changes in the function through the gait cycle. Variations in heel height are known to influence load distribution in weightbearing, thus affecting change in forefoot widths. Weight bearing in radiographs are commonly used to identify these changes, which may have clinical relevance. However, there are limited studies that accurately quantify the extent of these differences in the forefoot to be analysed effectively. Hence, there is a need to investigate different weight bearing conditions and its influence on forefoot width changes required for accurate analysis of imaging. This study's aim is to evaluate the significance and degree of foot splaying with different modes of weight-bearing and heel height to achieve optimum increase in forefoot width.Methods:32 volunteers with no clinical issues with their feet were selected for this study. Weight bearing photographs of their feet were reviewed by 2 foot and ankle surgeons (under blinded conditions) to ensure they were normal morphologically. The forefoot width is measured using sliding callipers between the medial margin of the first metatarsal head and lateral margin of the fifth metatarsal head when non weight bearing - NWB, partial weight bearing - PWB (dual leg stance) and full weight bearing - FWB (single leg stance). Single leg stance measurement is also taken at increasing heel heights of 2cm (FWB1), 4cm (FWB2) and 6cm (FWB3) using polyurethrane blocks. Each individual foot non weight-bearing width will act as its own control for the changes in the differing positions measured.Results:Statistical analysis of data demonstrated the results with the use of student t-test analysis via SPSS which showed statistically significant differences in forefoot width in both genders(p<0.05). There is an increasing trend of forefoot width as weightbearing conditions increase up to 2cm of elevated heel height. However, forefoot width decreases as heel height increases beyond 2cm in both genders. Female subjects have a higher trend of percentage of increase in mean forefoot width compared to males in all weightbearing conditions except for full weightbearing with 6cm heel height elevation.Conclusion:In conclusion, there is a linear trend of increase in forefoot width with increase from non-weightbearing up to 2cm heel height inclination. Full weightbearing with 2cm heel height inclination produces the widest foot splaying in this study. Larger future studies will need to be conducted to validate these findings.

A Comparison of Portable Ultrasonography and the Fluoroscopy for Evaluating Medial Ankle Instability: A Cadaveric Study

Category:Ankle; TraumaIntroduction/Purpose:Diagnosis of destabilizing deltoid ligament injuries remains challenging and is best identified with dynamic imaging techniques. This study aims to assess and compare medial clear space (MCS) distances in various stages of sequentially created supination external rotation (SER) ankle injury model using portable ultrasound (P-US) and fluoroscopy. We hypothesize that there is a strong correlation between the P-US and fluoroscopic measurements for the assessment of medial ankle instability in SER type ankle injury during the gravity stress test (GST), weight-bearing, or external rotation stress test.Methods:Ten cadaveric specimens were used for assessing medial ankle instability. The assessment was performed with all structures intact, and later with sequential transection of the anterior inferior tibiofibular ligament (Stage I), fibular (Weber-B fracture) (Stage II), posterior inferior tibiofibular ligament (Stage III), superficial deltoid ligament (Stage IVa), and deep deltoid ligament (Stage IVb). In all scenarios, the GST, external rotation stress test(45N), and Simulated weight-bearing condition(750N) were performed. The P-US measurement of the MCS was assessed at the anteromedial and inferomedial aspect of the ankle joint. Three different MCS distances were measured, as demonstrated in Figure 1. The fluoroscopic MCS measurements were assessed on a true mortise ankle view achieved during each loading condition. Spearman rank correlation was used to investigate the relationship between the P-US and fluoroscopic measurements. The inter- and intra-observer agreement was assessed using the intraclass correlation coefficient (ICC) through a two-way mixed-effects model with absolute agreement.Results:The P-US and fluoroscopic assessed medial ankle instability values during the GST, weight-bearing, and the external rotation stress test increased as the SER ankle injury stage progressed. The P-US values measured during all stress tests demonstrated a moderate to strong positive correlation with those measured with the fluoroscopy (Spearman's rank correlation ranged from 0.61-0.93, p-values <0.001). Inter-rater (P-US: 0.97, 95%CI: 0.96-0.98) and intra-rater reliability (P-US, 0.95, 95%CI: 0.94-0.96) for the P-US measurements were all substantial.Conclusion:The use of dynamic P-US to measure the MCS appears to be a reliable and repeatable technique. The P-US MCS measurement values measured in the SER ankle injury model during the GST, weight-bearing and the external rotation stress test are well correlated with those values measured with fluoroscopy. Therefore, the dynamic P-US with stress examination of the ankle has the potential to quantify medial ankle instability in a radiation-free, non-invasive, low cost, and point of care setting.

Weight Bearing CT Analysis of the Transverse Tarsal Joint During Eversion and Inversion

Category:Basic Sciences/Biologics; HindfootIntroduction/Purpose:Current understanding of the kinematics of the transverse tarsal joint continues to evolve. Unfortunately, most prior studies have been in cadavers or under non-physiologic conditions. Weight bearing CT scans may provide more accurate in vivo information about the position of the transverse tarsal joint during eversion and inversion.Methods:Institutional Review Board approval was obtained. Five normal volunteers underwent bilateral weight bearing cone- beam PedCAT scans (CurveBeam LLC, Hatfield, PA) while standing on platforms that positioned both hindfeet in 20o of valgus and then 20o of varus. The CT scans had a field-of-view diameter of 350 mm and a field-of-view height of 200 mm. The scan exposure time was 9 seconds, with a total scan time of 54 seconds. The datasets were reconstructed using filtered back projection with 0.37mm isotropic voxels. The resulting volumes were then segmented, identifying the [x, y, z] coordinates that comprised each bone. Each bone of the hindfoot was segmented on the scan images and the motion between the talus and calcaneus was analyzed. A similar analysis was done for motion between the navicular and cuboid. Two-tailed paired Student's t- tests were used to compare the angle and distance measurements between valgus and varus positions.Results:In the coronal plane, the axis of the talus rotated by 17.0° relative to the axis of the calcaneus as the hindfoot moved from eversion to inversion (p=0.03). The distance between the centers of the talar head and the anterior calcaneus also moved closer to each other by 7.1 mm (p=0.00005). There was no significant change in angle or distance between the navicular and cuboid when moving from eversion to inversion. The angle between the navicular and cuboid axes changed 2.1° (p=0.7), while the distance changed 0.8 mm (p=0.7)Conclusion:Previous work proposed that the transverse tarsal joint locking mechanism occurs from the talonavicular and calcaneocuboid joint axes diverging (less parallel) as the hindfoot inverts. The current weight bearing CT data shows that not only do the talar and calcaneal axes rotate relative to each other during inversion, but the center of the talar head and anterior calcaneus translate to move closer together. Because the navicular and cuboid do not move, transverse tarsal joint locking may occur due to tightening of the joint capsules and ligaments. Further in vivo study is warranted, especially under dynamic weightbearing conditions.

Comparison of Gait parameters among the adults (18-24) with and without flatfoot – A Cross sectional study

Background: Flat foot is a common deformity in which the medial longitudinal arch is eliminated or reduced, subtalar joint is pronated and the calcaneus achieves valgus position under- weight bearing conditions. Any feet disorder can alter the biomechanics of the entire lower limb. The aim of the study was to compare the gait parameters (Cadence, stride length, step length and pace) among the adults (18-24) with and without flat foot. Methodology: It was a cross-sectional study with 3 months duration. Total 56 young adults (18-24) with and without flatfoot were recruited with purposive sampling method. the categorization of the type of arch using Arch-Height index. The Outcome measures were Gait parameters (cadence, distance walked in one minute, speed, step length, stride length) which were noted by pedometer of Smart watch and stride length, step length by using formula using cadence and distance findings. Result: Comparison analysis was done by using unpaired t-test. On comparison of various Gait parameters between normal and flat foot individuals such as cadence (p=0.7), distance walked in one minute (p= 0.96), speed (p=0.78), step length (p= 0.98), stride length (p= 0.92), there was no significant difference between two groups. Conclusion: The study concludes that there is no difference in gait parameters between flatfoot and normal foot.

Effect of limb rotation on radiographic alignment measurement in mal-aligned knees

PurposeLong-leg-radiography (LLR) is commonly used for the measurement of lower limb alignment. However, limb rotations during radiography may interfere with the alignment measurement. This study examines the effect of limb rotation on the accuracy of measurements based on the mechanical and anatomical axes of the femur and tibia, with variations in knee flexion and coronal deformity.MethodsForty-five lower limbs of 30 patients were scanned with CT. Virtual LLRs simulating five rotational positions (neutral, ± 10^{circ }, and ± 20^{circ } internal rotation) were generated from the CT images. Changes in the hip–knee–ankle angle (HKA) and the femorotibial angle (FTA) were measured on each image with respect to neutral values. These changes were related to knee flexion and coronal deformity under both weight- and non-weight-bearing conditions.ResultsThe measurement errors of the HKA and FTA derived from limb rotation were up to 4.84 ± 0.66^{circ } and 7.35 ± 0.88^{circ }, respectively, and were correlated with knee flexion (p < 0.001) and severe coronal deformity (p < 0.001). Compared with the non-weight-bearing position, the coronal deformity measured in the weight-bearing condition was 2.62^{circ } greater, the correlation coefficients between the coronal deformity and the deviation ranges of HKA and FTA were also greater.ConclusionsFlexion and severe coronal deformity have a significant influence on the measurement error of lower limb alignment. Errors can be amplified in the weight-bearing condition compared with the non-weight-bearing condition. When using HKA and FTA to represent the mechanical axis and the anatomical axis on LLR, limb rotation impacts the anatomic axis more than the mechanical axis in patients with severe deformities. Considering LLR as the gold standard image modality, attention should be paid to the measurement of knee alignment. Especially for the possible errors derived from weight-bearing long-leg radiographs of patients with severe knee deformities.

The MRI-based 3D morphologic changes of knee meniscus under knee weight-bearing and early flexion conditions

There are few studies investigate morphologic changes of knee meniscus in vivo mechanical loading and three-dimensions (3D) deformation and displacement of the whole meniscus between in vivo mechanical loading and unloading conditions are still unclear. To investigate the displacements and 3D morphological changes of the menisci under knee weight-bearing and early flexion conditions in healthy adults using a Magnetic Resonance Imaging (MRI)-compatible loading device (a 3.0 T MR imaging system) combined with a newly developed 3D comparison technique. Fifteen healthy volunteers were recruited in this cross-sectional observational study. Each subject underwent MRIs of their dominant right knee in eight different scanning conditions using a 3.0-T MRI scanner with a custom-made MRI-compatible loading device. The knee meniscus images were 3D reconstructed, and dimensional comparisons were made for each meniscal model with baseline (0°-unloaded model). The morphologic changes of the meniscal-anterior horn (AH), body (BD), and posterior horn (PH) regions were expressed as mean positive and negative deviations. The displacements were further investigated, and the meniscal extrusions of different subregions were measured. The morphologic changing patterns of human meniscus under loading and flexions were presented using 3D chromatic maps. The bilateral menisci were generally shifting laterally and posteriorly in most flexion angles and were changing medially and anteriorly under fully extended knee loading conditions. The mean deviations were more significant with loading at 0° of knee flexion, while the PH region in the lateral side changed further posteriorly with loading in 30° flexion. Most of the differences were not significant in other flexion angles between loading conditions. The extrusion of meniscus’s medial body was greater in full extension compared to any other flexing angles. Mechanical loading can significantly deform the menisci in knee extension; however, this effect is limited during knee flexion. Current study can be used as a reference for the evaluations of the integrity in meniscal functions.

Comparative radiographic analysis of three-dimensional innate mobility of the foot bones under axial loading of humans and African great apes.

The human foot is considered to be morphologically adapted for habitual bipedal locomotion. However, how the mobility and mechanical interaction of the human foot with the ground under a weight-bearing condition differ from those of African great apes is not well understood. We compared three-dimensional (3D) bone kinematics of cadaver feet under axial loading of humans and African great apes using a biplanar X-ray fluoroscopy system. The calcaneus was everted and the talus and tibia were internally rotated in the human foot, but such coupling motion was much smaller in the feet of African great apes, possibly due to the difference in morphology of the foot bones and articular surfaces. This study also found that the changes in the length of the longitudinal arch were larger in the human foot than in the feet of chimpanzees and gorillas, indicating that the human foot is more deformable, possibly to allow storage and release of the elastic energy during locomotion. The coupling motion of the calcaneus and the tibia, and the larger capacity to be flattened due to axial loading observed in the human foot are possibly morphological adaptations for habitual bipedal locomotion that has evolved in the human lineage.

Arch Height Index, Arch Rigidity Index and Arch Stiffness Values in a Symptomatic Population

Studies of arch height index (AHI), arch rigidity index (ARI), and arch stiffness have primarily focused on healthy populations. Normative values of the aforementioned measurements in a pathologic sample may be useful in identifying relationships between arch structure and pathology. AHI was obtained bilaterally at 10% and 90% weightbearing conditions using the AHI measurement system. ARI and arch stiffness were calculated using AHI measurements. Dependent t tests compared right and left, dominant and nondominant, and injured and noninjured limbs. Dominant feet were compared between sexes using independent t tests. Relationships between arch stiffness and subcategories were examined using the coefficient of determination (R2). One-way analyses of variance determined differences between arch structure and number of pathologies or body mass index (BMI). A total of 110 participants reported one (n = 55), two (n = 38), or three or more (n = 17) pathologies. Plantar fasciitis (n = 31) and hallux valgus (n = 28) were the most common. AHI, ARI, and arch stiffness did not differ between limbs or sexes for any comparisons. Between subgroups of BMI and number of pathologies, BMI influenced AHI (10% weightbearing) and arch stiffness (P < .05). Arch stiffness showed a weak relationship to AHI, where a higher AHI was associated with a stiffer arch (R2 = 0.06). Normative arch structure values were established in a pathologic sample with a large incidence of plantar fasciitis and hallux valgus. Understanding relationships between arch structure and pathology is helpful for clinicians and researchers.

RECENT ADVANCES IN POLYMERIC HYDROGEL SCAFFOLDS FOR SKIN TISSUE ENGINEERING AND REGENERATIVE MEDICINE

Lack of self-healing capability in skin tissue defects caused by various traumatic conditions often leads to a challenging situation for clinical practitioners. Although various procedures are offered in clinics, some of which effectively restores the skin tissue to some patients, none of them result in an adequate tissue repair that can withstand mechanical stresses under natural weight-bearing conditions. The ability of hydrogels to form 3D networks, which can be fine-tuned using biocompatibility and biodegradability factors, has sparked much interest in these hydrophilic polymers. A systematic overview of emerging hydrogel-based therapies for skin tissue repair is presented in the current study to address the unsolved issue of skin tissue defects and test whether such therapeutic approaches may enhance the healing process where skin tissue has been damaged.

Radiological assessments and clinical results of intra-articular osteotomy for traumatic osteoarthritis of the ankle

IntroductionTraumatic osteoarthritis of the ankle joint caused after malleolar fractures of the ankle and tibial plafond fractures are frequently observed in comparatively young and highly active patients. Since the ankle movement in these patients is in general, comparatively favorable, orthopedists may sometimes have difficulty in deciding on a treatment policy. In our department, when treating traumatic osteoarthritis patients having a movable range within their ankle joints, we proactively applied distal tibial oblique osteotomy (DTOO) developed by Dr. Teramoto in 1994 or intra-articular osteotomy developed based on DTOO concepts such as distal tibial intra-articular osteotomy (DTIO) and distal fibular oblique osteotomy (DFOO).The objectives of the current study are to radiologically assess the ankle joint after intra-articular osteotomy for traumatic ankle osteoarthritis and evaluate the change in configuration of the ankle joint. This study summarizes the clinical results of intra-articular osteotomy obtained through the above-mentioned study. Patients and methodsThe subjects of this study were 20 patients diagnosed with traumatic osteoarthritis who were surgically treated for a total of 20 ankles. All patients underwent treatment with intra-articular osteotomy and were evaluated retrospectively for the following parameters: surgical procedure, fixation devices, clinical results based on the Japanese Society for Surgery of the Foot ankle/hindfoot scale (hereafter, JSSF scale) and post-operative adverse events. They were also assessed radiologically with pre- and post-operative anterior-posterior (AP) and lateral weight-bearing ankle radiographs. ResultsThe 20 patients consisted of 12 males and 8 females. The median age at surgery was 49 years old (range 14 - 87 years old) and the average follow-up period was 42 months (range 19 to 121 months). DTOO was applied to 10 cases, DFOO to 2 cases, DTOO and DFOO to 2 cases, medial-distal tibial intra-articular osteotomy (M-DTIO) and DFOO to 1 case, lateral-distal tibial intra-articular osteotomy (L-DTIO) and DFOO to 3 cases, M-DTIO followed by DTOO and DFOO to 1 case, and DTOO followed by low tibial osteotomy (LTO) to 1 case. Fixation devices utilized included circular external fixator for 15 cases, locking compression plate (LCP) to 3 cases, LCP and Kirschner-wire (K-wire) to 1 case, and screw and K-wire to 1 case. Radiological assessment revealed significant changes in the following parameters after surgery: tibial ankle surface angle (TAS, P= 0.0203), tibiotalar surface angle (TTS, P= 0.0021), medial malleolar angle (MMA, P= 0.0217), empirical axis (EA, P= 0.0019), fibular angle (FA, P= 0.0002), talar tilt angle (TTA, P= 0.0374), and tibial lateral surface angle (TLS, P= 0.0279). The JSSF scale also improved significantly after surgery (pre-operative JSSF scale: 51.1±11.0, post-operative JSSF scale: 89.2±8.2), p=0.0001. ConclusionIntra-articular osteotomy may change the radiological configuration of the ankle in a weight-bearing state. The present study showed very good short-term clinical results. Intra-articular osteotomy can prove a viable surgical option applicable for treatment of patients with traumatic ankle osteoarthritis having a reasonable range of motion within their ankle joints.

Evaluation of the Foot Arch in Partial Weightbearing Conditions.

Weightbearing plain radiography or computed tomography (CT) is used for diagnosis or treatment selection in foot disorders. This study compared foot alignment between full weightbearing (50% body weight [BW] per foot) plain radiography and nonweightbearing (0% BW) or partial weightbearing (10% BW per foot) CT scans. Subjects had both full (50% BW per foot) weightbearing plain radiographs and either a nonweightbearing (0% BW) or a partial weightbearing (20% BW or 10% BW per foot) CT scan. Feet (n = 89) had been previously classified as pes cavus (n = 14/17 [subjects/feet]), neutrally aligned (NA; 20/30), asymptomatic pes planus (APP; 18/24), and symptomatic pes planus (SPP; 15/18). Lateral talometatarsal angle (LTMA) and calcaneal pitch angle were compared between weightbearing radiography and maximum-intensity projection images generated from CT. Significant differences in LTMA were found between nonweightbearing CT scans and full (50% BW per foot) weightbearing plain radiographs: the mean difference was 6.6 degrees in NA, 9.2 degrees in APP, and 11.3 degrees in SPP (P < .0001); no significant difference in LTMA was found for pes cavus. Although the interaction of foot type (P = .084) approached statistical significance, pairwise differences between 10% weightbearing and 50% weightbearing images by foot type were significant but small. The 50% weightbearing condition resulted in calcaneal pitch angles the same or slightly lower or higher than those of the 10% weightbearing and nonweightbearing images. LTMA and calcaneal pitch angle measurements made on full (50% BW per foot) weightbearing plain radiographs and non- (0%) or partial (10% BW per foot) weightbearing angles from CT scans were strongly correlated. Different foot types have similar 2-dimensional sagittal plane morphologies with partial weightbearing (10% BW per foot) CT scans and, to a lesser degree, nonweightbearing (0%) neutral-position CT scans when compared to full weightbearing (50% BW per foot) plain radiographs. Level III, retrospective case control study.

The Effects Of Different Blood Flow Restriction Cuff Pressures On Dynamic Knee Valgus Angles

PURPOSE: To examine the effects of two different Blood Flow Restriction (BFR) cuff pressures after three weeks of cycle training on knee stability, specifically dynamic knee valgus (DKV) angles on healthy adults. METHODS: Ten healthy participants (26 ± 3 years; 6 males; 4 females) were randomized to: BFR with 60% occlusion, and BFR with 80% occlusion while cycling in an ergometer for 15 minutes at 70 rpm, three times a week for three weeks. Knee stability was measured during a three 5-repetition single-leg step down per leg, for the right leg, from a 30-centimeter firm and stable platform. Participants were given one minute of rest between trials to prevent fatigue. The average knee valgus among trials was used for analysis. Valgus motion was tracked through a 10-camera motion analysis capture system (120 Hz sampling rate). Valgus was measured at the lowest achievable depth of the step down. Comparison of valgus angles were done at baseline and at three weeks. Given normally distributed data, a 2 x 2 (group by time) ANOVA was used to perform between and within-group comparisons. Statistical significance was set at an alpha of 0.05 for all comparisons. RESULTS: Although the 80% occlusion group reduced knee valgus by 2.8 degrees, between and within-group comparisons were not statistically significant for DKV. CONCLUSIONS: It appears at this point that cycling with BFR cuffs does not alter knee stability in weight bearing conditions for healthy individuals. This lack of effectiveness could be due to the short time frame between baseline and follow-up or a bigger sample size will be needed to find statistically significant differences. Future research should complement treatment techniques design to improve knee stability with BFR to explore the effects of combined interventions.

The Effects of a Medial Heel Wedge on the Weight-Bearing Response of Hindfoot Valgus and the Total Weight-Bearing Responses of the Navicular and Talus Bones

OBJECTIVES Medial heel wedges are commonly prescribed to manage the weight-bearing response of hindfoot valgus and the total weight-bearing responses of the navicular and talus bones. Previous studies have reported that a medial heel wedge is effective in the management of musculoskeletal injuries. However, it remains unclear the effect of a medial heel wedge on the weight-bearing responses of footarch bones in vivo. To clarify the effects of a medial heel wedge on the weight-bearing response of hindfoot valgus and the total weight-bearing responses of the navicular and talus bones is necessary to understand how best to treat musculoskeletal injuries clinically. The purpose of our study was to clarify the effects of a medial heel wedge on the weight-bearing response of hindfoot valgus and the total weight-bearing responses of the navicular and talus bones.METHODS Twenty-five healthy males were analyzed. We obtained MRI scanning of the right foot under non-loading (NL) and full weight-bearing (FW) conditions. Participants wore two insole types, a flat insole and a medial heel wedge. To evaluate the weight-bearing response in hindfoot valgus, the hindfoot alignment view (HAV) was measured. We also measured navicular and talus bone positions and calculated the total positional changes of the navicular and talus bones (ΔTPCN, ΔTPCT) from the vertical and medial displacements using the Pythagorean theorem.RESULTS Significant interactions were observed with the HAV. Under both NL and FW conditions, the HAV was smaller on the medial heel wedge than on the flat insole. In addition, the ΔTPCN was significantly smaller on the medial heel wedge than on the flat insole. However, no significant differences were observed for ΔTPCT.CONCLUSIONS Our results suggest that use of a medial heel wedge decreases hindfoot valgus values under both NL and FW conditions and stabilizes the total weight-bearing response of the navicular bone.

Cartilage Repair Capacity within a Single Full-Thickness Chondral Defect in a Porcine Autologous Matrix-Induced Chondrogenesis Model Is Affected by the Location within the Defect.

Large articular cartilage defects are a challenge to regenerative surgery. Biomaterial scaffolds might provide valuable support for restoration of articulating surface. The performance of a composite biomaterial scaffold was evaluated in a large porcine cartilage defect. Cartilage repair capacity of a biomaterial combining recombinant human type III collagen (rhCo) and poly-(l/d)-lactide (PLA) was tested in a porcine model. A full-thickness chondral defect covering the majority of the weightbearing area was inflicted to the medial femoral condyle of the right knee. Spontaneous cartilage repair and nonoperated healthy animals served as controls. The animals were sacrificed after a 4-month follow-up. The repair tissue was evaluated with the International Cartilage Repair Society (ICRS) macroscopic score, ICRS II histological score, and with micro-computed tomography. Additionally, histopathological evaluation of lymph nodes and synovial samples were done for toxicological analyses. The lateral half of the cartilage defect in the operated groups showed better filling than the medial half. The mean overall macroscopic score for the rhCo-PLA, spontaneous, and nonoperated groups were 5.96 ± 0.33, 4.63 ± 0.42, and 10.98 ± 0.35, respectively. The overall histological appearance of the specimens was predominantly hyaline cartilage in 3 of 9 samples of the rhCo-PLA group, 2 of 8 of the spontaneous group, and 9 of 9 of the nonoperated group. The use of rhCo-PLA scaffold did not differ from spontaneous healing. The repair was affected by the spatial properties within the defect, as the lateral part of the defect showed better repair than the medial part, probably due to different weightbearing conditions.

Association between medial meniscus extrusion under weight-bearing conditions and pain in early-stage knee osteoarthritis.

This study aimed to investigate the association between the severity of medial meniscus extrusion (MME) under weight bearing and pain in patients with early-stage knee osteoarthritis (OA). Twenty-eight patients with symptomatic early-stage knee OA (Kellgren and Lawrence grade ≤ 2) who visited our outpatient clinic between 2016 and 2018 were included in this cross-sectional study (mean age: 58.0 ± 11.6years, female: n = 10). MME was evaluated under weight-bearing conditions using ultrasonography. Patients were divided into two groups according to the severity of MME under weight bearing: those with MME ≥ 3mm were assigned to the severe group, whereas those with MME < 3mm were assigned to the mild group. The knee injury osteoarthritis outcome score (KOOS) system was used to evaluate knee pain. The incidence of bone marrow lesions (BMLs) was evaluated using magnetic resonance images. The KOOS pain score was significantly lower in the severe group than in the mild group (P < 0.05). The incidence of BMLs was significantly higher in the severe group (69%) than in the mild group (7%) (P < 0.001). Patients with early-stage knee OA who have greater MME under weight-bearing have more intense knee pain and a higher incidence of BMLs.

Dynamic Radiostereometry Evaluation of 2 Different Anterior Cruciate Ligament Reconstruction Techniques During a Single-Leg Squat.

Background:Lateral extra-articular tenodesis in the context of anterior cruciate ligament (ACL) reconstruction (ACLR) is performed to better control anterolateral knee instability in patients with high-grade preoperative pivot shift. However, some authors believe these procedures may cause lateral compartment overconstraint, affecting knee motion in daily life.Purpose/Hypothesis:The primary aim of the present study was to identify kinematic differences during the execution of an activity under weightbearing conditions between knees having undergone ACLR using anatomic single-bundle (SB) versus single-bundle plus lateral plasty (SBLP) techniques. The secondary aim was to compare the postoperative kinematic data with those from the same knees before ACLR and from the healthy contralateral knees in order to investigate if ACLR was able to restore physiologic knee biomechanics during squat execution. The hypotheses were that (1) the SBLP technique would allow a better restoration of internal-external (IE) knee rotation than would SB and (2) regardless of the technique, ACLR would not fully restore physiologic knee biomechanics.Study Design:Randomized controlled trial; Level of evidence, 2.Methods:In total, 32 patients (42 knees) were included in the study. Patients were asked to perform a single-leg squat before surgery (ACL-injured group, n = 32; healthy contralateral group, n = 10) and at minimum 18-month follow-up after ACLR (SB group, n = 9; SBLP group, n = 18). Knee motion was determined using a validated model-based tracking process that matched patient-specific magnetic resonance imaging bone models to dynamic biplane radiographic images under the principles of roentgen stereophotogrammetric analysis. Data processing was performed using specific software. The authors compared IE and varus-valgus rotations and anterior-posterior and medial-lateral translations among the groups.Results:The mean follow-up period was 21.7 ± 4.5 months. No kinematic differences were found between the SB and SBLP groups (P > .05). A more medial tibial position (P < .05) of the ACL-injured group was reported during the entire motor task and persisted after ACLR in both the SB and the SBLP groups. Differences in IE and varus-valgus rotations were found between the ACL-injured and healthy groups.Conclusion:There were no relevant kinematic differences between SBLP and anatomic SB ACLR during the execution of a single-leg squat. Regardless of the surgical technique, ACLR failed in restoring knee biomechanics.Registration:NCT02323386 (ClinicalTrials.gov identifier).

Effect of soft inflatable orthosis on the medial longitudinal arch in patients with flexible flatfoot deformity

Orthoses can stabilize the foot and restore the medial longitudinal arch for symptomatic flexible flatfoot. However, the effectiveness of orthoses remains controversial. The purpose of this study was to evaluate effectiveness of a customized soft inflatable orthosis on the medial longitudinal arch of flexible flatfoot patients under load. We obtained CT scans of the feet of 14 healthy volunteers and 14 patients with flexible flatfoot under non- and simulated weight-bearing conditions. Then CT scans under the same conditions were taken for patients with flexible flatfoot equipped with soft inflatable orthosis. Three-dimensional models of the medial longitudinal arch and hindfoot were constructed from CT images. The three-dimensional mobility of the medial longitudinal arch joints under load was compared between patients with flexible flatfoot equipped with soft inflatable orthosis or not. From non- to simulated weight-bearing condition, the eversion and dorsiflexion of the talocalcaneal joint, the eversion of the talonavicular joint, the abduction and dorsiflexion of the cuneonavicular joint, and the dorsiflexion of the first tarsometatarsal joint were significantly larger in patients with flexible flatfoot than healthy volunteers. The customized soft inflatable orthosis could reduce the eversion of the talonavicular joint and the eversion and dorsiflexion of the talocalcaneal joint. The soft inflatable orthosis is effective to improve medial longitudinal arch height and reduce excessive mobility of joints for flexible flatfoot deformity. The results of this study could provide evidence for the optimal orthosis design to treat flexible flatfoot in the future.

Comparative Reliability of a Novel Electromechanical Device and Handheld Ruler for Measuring First Ray Mobility

Quantifying first ray mobility is crucial to understand aberrant foot biomechanics. A novel device (MAP1st) that can perform measurements of first ray mobility in different weightbearing conditions, foot alignments, and normalization was tested. The reliability of these measurement techniques was assessed in comparison to a handheld ruler considered representative of the common clinical examination. The study included 25 participants (50 feet). Two independent raters performed baseline, test-retest, and remove-replace measurements of first ray mobility with MAP1st and the handheld device. The effects of non-, partial, and full weightbearing in subtalar joint neutral and the resting calcaneal stance position were assessed. Measurement normalization relative to foot size was also investigated. Intra- and interclass correlation coefficients (ICCs) were calculated for each device between the 2 raters. In addition, Bland-Altman plots were constructed to determine if fixed biases or substantial outliers were present. Similar intrarater ICC values were found for both devices (≥0.85). However, interrater ICC values were substantially improved by MAP1st compared with the handheld device (0.58 vs 0.06). Bland-Altman plots demonstrated biases of 1.27 mm for the handheld ruler, and 2.88 to 0.05 mm and -1.16 to 0.00 for linear and normalized MAP1st measurements, respectively. Improved reliability was achieved with MAP1st for normalized assessments of first ray mobility while the foot was placed in partial- and full-weightbearing resting calcaneal stance positions. MAP1st provided reliable assessments of partial- and full-weightbearing first ray mobility. It should help investigators to explore the potential relationships between first ray function and aberrant foot biomechanics in future research. Level II, prospective cohort study.

Frontal plane ankle stiffness increases with weight-bearing

Ankle sprains are among the most common musculoskeletal injuries. They are not isolated innocuous injuries as 30–40% of people who sprain their ankles develop chronic ankle instability. Ankle instability is typically assessed under passive unloaded conditions, ignoring any potential contribution of joint loading or muscle activation to the maintenance of ankle stability. Thus, the relevance of unloaded ankle stability assessments to the evaluation of impairments in chronic ankle instability or the prediction of future ankle sprains is questionable. Ankle impedance, which quantifies the resistance to an imposed rotation, has often been used to quantify ankle stability. However, few studies have investigated impedance in the frontal plane where sprains occur, and none have systematically investigated the effect of weight-bearing on ankle impedance. The objective of this study was to determine whether weight-bearing affects frontal plane ankle impedance. We had subjects systematically alter the weight on the tested ankle, while imposed frontal plane rotations were applied to estimate the impedance. We found that ankle stiffness, the static component of impedance, increased proportionally with the weight on the ankle. This increase in stiffness was due to a combination of the increase loading on the joint and the increase in muscle activation that occurs during weight-bearing. Finally, we found that men had a greater stiffness than women over the majority of the weight-bearing range. These results highlight the importance of clinically assessing ankle stability during weight-bearing conditions to better determine the impairments in chronic ankle instability and identify those at risk for ankle sprains.

Influence of posterior tibial slope on three-dimensional femorotibial alignment under weight-bearing conditions in healthy Japanese elderly people.

Assessment of three-dimensional (3D) femorotibial alignment is essential for successful knee osteoarthritis treatment in the elderly. The complex morphology of the posterior tibial slope (PTS) might have an influence on sagittal and rotational alignment and the positional relationship between the femur and tibia in the anterior-posterior (AP) direction under weight-bearing conditions. This study aimed to clarify the association between the PTS and 3D femorotibial alignment under weight-bearing conditions in healthy Japanese elderly individuals. We investigated the 3D femorotibial alignment of 110 lower extremities of 55 healthy individuals (26 women, 29 men, mean age: 70 ±6 years). Using our previously reported 3D-to-2D image registration technique, we evaluated the 3D hip-knee-ankle angle (3DHKA) in the sagittal plane, rotational alignment, and the distance between the femoral and tibial origins in the AP direction (tibial AP position) as femorotibial alignment parameters under weight-bearing conditions. We assessed the medial and lateral PTS and their angular difference (PTS difference) as PTS parameters. Stepwise multiple linear regression analysis was performed using PTS parameters and other possible confounders (age, sex, height, and weight) as the independent variables and femorotibial alignment parameters as the dependent variable. Weight (𝛽 =0.393, p <0.001) and lateral PTS (𝛽 =0.298, p <0.001) were the predictors associated with 3DHKA in the sagittal plane. Lateral PTS (𝛽 =0.304, p =0.001) was the only predictor associated with the tibial AP position. Sex (𝛽 = -0.282, p =0.002) and PTS difference (𝛽 = -0.231, p =0.012) were associated with rotational alignment. We found that a steeper lateral PTS resulted in a more flexed knee and anterior tibia. The PTS difference was positively correlated with tibial external rotation. Our data could be used as the standard reference for realignment surgery to ensure PTS is appropriately maintained.