Coronal Plane Calcaneal-Talar Orientation in Varus Ankle Osteoarthritis

Category:

Hindfoot; Ankle; Ankle Arthritis

Introduction/Purpose:

We do not yet fully understand how the subtalar joint position is related to the varus osteoarthritic ankle joint. The purposes of this study were 1) to investigate the coronal orientation of the calcaneus relative to the talus according to the ankle osteoarthritis stage, talar tilt (TT), and 2) to determine if there is a TT threshold at which apparent subtalar compensation begins to fade.

Methods:

We retrospectively reviewed 132 ankles that underwent WBCT for varus ankle osteoarthritis. The TT, subtalar inclination angle (SIA), and calcaneal inclination angle (CIA) were measured using WBCT. Ankles were divided into 5 groups according to Takakura stage and 2 groups according to the apparent compensation status of the subtalar joint and compared the index of the inclination of the subtalar joint relative to the ankle (SIA) or the index of the inclination of the calcaneus relative to the ankle (CIA). Additionally, we explored the relationship between SIA or CIA and the TT.

Results:

Apparent subtalar compensation (SIA and CIA) was significantly lower in Takakura stages 3b and 4. The SIA and CIA significantly differed according to the apparent compensation status (p<.001 and p=.030, respectively). The CIA of the noncompensated group varied widely, while the SIA was relatively constant. Furthermore, TT was greater than 9.5, which indicated a high probability of a noncompensated heel. (sensitivity, 92.6%; specificity, 89.7%).

Conclusion:

The position of the calcaneus has a appears compensatory with coronal plane orientation in varus ankle osteoarthritis when the TT is < than 9.5°.

Relationship Between Talofibular Impingement and Increased Talar Tilt in Incongruent Varus Ankle Osteoarthritis

Category:

Ankle; Ankle Arthritis

Introduction/Purpose:

Recently, talofibular bony impingement has been postulated to be a source of ankle pain. This study aimed to evaluate the relationship between talofibular impingement and increased talar tilt in incongruent varus ankle OA patients using bilateral weightbearing CT.

Methods:

Incongruent varus ankle osteoarthritis was defined as a talar tilt of more than 4° on standard ankle anteroposterior radiographs. We retrospectively reviewed 30 patients with unilateral incongruent varus ankle osteoarthritis with normal alignment of the contralateral ankle. All patients underwent bilateral weightbearing computed tomography and standing plain radiographs. The talar tilt and the distance between the talar lateral process and lateral malleolar tip were measured from a standing ankle anteroposterior radiograph of both sides. Talar and fibular spurs were assessed on the coronal and axial views of weightbearing computed tomography. After simulating the correction of the talar tilt in varus ankle osteoarthritis, talofibular bony impingement was reassessed.

Results:

On the varus side, the distance between the talar lateral process and the lateral malleolar tip was significantly shorter than that on the contralateral side (p < .001). Talar spur was present in the varus side of all 30 patients on the axial view of weightbearing computed tomography and in the control side of 10 patients. After the simulation of talar tilt correction, talofibular impingement (overlap) occurred in all 30 patients with a larger extent in the severe talar tilt subgroup (p < .001).

Conclusion:

Talofibular impingement by lateral gutter osteophytes is closely related to increased talar tilt in patients with incongruent varus ankle osteoarthritis. Therefore, lateral gutter osteophytes should be resected to stabilize mortise and improve clinical outcomes.

Hindfoot Motion Analysis by Subtalar Compensation and Ankle Osteoarthritis Stage using a 3D Multi- Segment Foot Model

Category:

Hindfoot

Introduction/Purpose:

Biomechanics of the hindfoot in ankle osteoarthritis (OA) have not yet fully understood. We aimed to identify hindfoot motions by gait analysis using multi-segment foot model (MFM) according to the stage of ankle OA or hindfoot alignment determined by the presence of subtalar compensation.

Methods:

We retrospectively reviewed the medical records, simple radiographs, and gait MFM data from 54 ankles which admitted to our hospital for the treatment of advanced ankle OA. Spatiotemporal gait parameters and 3-dimensional motions of hindfoot segment were analyzed according to sex, age, body mass index, the Takakura classification, and the presence of subtalar compensation.

Results:

As a result, all spatiotemporal gait parameters showed no significant difference according to the presence of subtalar compensation and the stage of ankle OA. With regard to the relationship between hindfoot segmental motion and the stage of ankle OA, only normalized step width was significantly different from each other (p value=0.028). Average motion of hindfoot (decompensation versus compensation) showed no significant difference in sagittal and transverse plane. In coronal movement of hindfoot, there were collapsed curves in both groups, which had constant significant difference. In comparison of 3a, 3b, and 4 stages of Takakura, more advanced 3b stages of ankle OA had the smaller sagittal range of motion compared to 3a (p value=0.028). Coronal movement of hindfoot in Takakura 3a/3b/4 all showed relatively flat pattern.

Conclusion:

In conclusion, spatiotemporal parameters were not affected by the alignment state of the heel resulted from subtalar compensation. Sagittal range of hindfoot motion decreased in the advanced ankle OA. Coronal movement of subtalar joint in ankle OA, once it was disrupted, showed no change regardless of the stage of ankle OA or compensation state of the hindfoot.

Nanopore 16S Amplicon Sequencing Enhances the Understanding of Pathogens in Medically Intractable Diabetic Foot Infections

Category:

Diabetes

Introduction/Purpose:

Diabetic foot infections (DFIs) cause substantial morbidity and mortality. The mainstay of the treatment is empiric antibiotics and surgical debridement in severe cases.

Methods:

In this study, we performed nanopore 16S rDNA sequencing from the debridement specimens of DFIs. Fifty-four surgical debridement specimens obtained from 45 patients with medically intractable DFI were included. The 16S rDNA PCR was performed on each specimen, and Nanopore sequencing was performed for up to 3 h. The reads were aligned to the BLAST database, and the results were compared with conventional culture studies.

Results:

The 16S sequencing results revealed that the majority of the DFIs (44 of 54, 81.5%) were polymicrobial infections. All bacteria isolated by conventional culture studies were detected by 16S sequencing. Several anaerobes (Prevotella, Finegoldia, Anaerococcus, Bacteroides) were commonly identified by 16S sequencing but were frequently missed by culture studies. In many cases, certain bacteria only revealed by the 16S sequencing were more abundant than the bacteria isolated by the culture studies.

Conclusion:

In conclusion, nanopore 16S sequencing was capable of pathogen identification in DFIs and has many advantages over conventional culture studies. Nanopore 16S sequencing enables a comprehensive understanding of the bacteria involved in DFIs.

Coronal plane Calcaneal-Talar Orientation in Varus Ankle Osteoarthritis

BACKGROUND

We do not yet fully understand how the subtalar joint position is related to the varus osteoarthritic ankle joint. The purposes of this study were (1) to investigate the coronal orientation of the calcaneus relative to the talus according to the ankle osteoarthritis stage, talar tilt (TT), and (2) to determine if there is TT threshold at which apparent subtalar compensation begins to fade.

METHODS

We retrospectively reviewed 132 ankles that underwent weightbearing computed tomography (WBCT) for varus ankle osteoarthritis. The TT, subtalar inclination angle (SIA), and calcaneal inclination angle (CIA) were measured using WBCT. Ankles were divided into 5 groups according to Takakura stage and 2 groups according to the apparent compensation status of the subtalar joint and compared the index of the inclination of the subtalar joint relative to the ankle (SIA) or the index of the inclination of the calcaneus relative to the ankle (CIA). Additionally, we explored the relationship between SIA or CIA and the TT.

RESULTS

Apparent subtalar compensation (SIA and CIA) was significantly lower in Takakura stages 3b and 4. The SIA and CIA significantly differed according to the apparent compensation status (P < .001 and P = .030, respectively). The CIA of the noncompensated group varied widely, whereas the SIA was relatively constant. Furthermore, TT was greater than 9.5, which indicated a high probability of a noncompensated heel (sensitivity, 92.6%; specificity, 89.7%).

CONCLUSION

The position of the calcaneus appears compensatory with coronal plane orientation in varus ankle osteoarthritis when the TT is ≤9.5 degrees.

LEVEL OF EVIDENCE

Level IV, case series.

Change of In-Shoe Plantar Pressure According to Types of Shoes (Flat Shoes, Running Shoes, and High Heels)

Background

The type of footwear is one of several factors that affect foot pressure. Despite its usefulness in identifying pathology and preventing and treating foot-related diseases, the type of shoes has been investigated and compared in only a few studies. This study aimed to investigate differences in plantar pressure, induced by flat, running, and high-heeled shoes in healthy, young women.

Methods

A total of 27 healthy women (27 feet) with a mean age of 21.5 ± 2.03 years were included in this study. Based on demographic data, radiologic measurements, clinical scores, temporal gait parameters, and kinematic parameters of gait, we confirmed the participants had normal feet. Then, pedobarographic data were measured by dividing each foot into seven regions to compare the three types of shoes. Peak plantar pressure and pressure-time integral were calculated using the Pedar-X system. The one-way analysis of variance and the Kruskal-Wallis test with Mann Whitney U-test were used for statistical analyses.

Results

Regarding the 7 regions of the foot, flat shoes resulted in a significantly higher pressure than running shoes in the hallux and lesser toes and the highest pressure in the metatarsal head (MTH) 3-5 and the hindfoot. In contrast, in the MTH 1 and MTH 2 regions, the high-heeled shoes had the highest measured pressure, followed by the flat shoes. Lastly, there was no high pressure in running shoes in any region except for the midfoot compared to the other shoes.

Conclusions

It can be inferred from our findings that flat and high-heeled shoes can generate a considerable burden on specific parts of the foot, which will aid in choosing appropriate shoes. Also, wearing running shoes places less burden on the overall foot.

Relationship between talofibular impingement and increased talar tilt in incongruent varus ankle osteoarthritis

PurposeThis study aimed to evaluate the relationship between talofibular impingement and increased talar tilt in incongruent varus ankle osteoarthritis. Methods: Incongruent varus ankle osteoarthritis was defined as a talar tilt of more than 4° on standard ankle anteroposterior radiographs. We retrospectively reviewed 30 patients with unilateral incongruent varus ankle osteoarthritis with normal alignment of the contralateral ankle. All patients underwent bilateral weightbearing computed tomography and standing plain radiographs. The talar tilt and the distance between the talar lateral process and lateral malleolar tip were measured from a standing ankle anteroposterior radiograph of both sides. Talar and fibular spurs were assessed on the coronal and axial views of weightbearing computed tomography. After simulating the correction of the talar tilt in varus ankle osteoarthritis, talofibular bony impingement was reassessed. Results: On the varus side, the distance between the talar lateral process and the lateral malleolar tip was significantly shorter than that on the contralateral side (p < .001). Talar spur was present in the varus side of all 30 patients on the axial view of weightbearing computed tomography and in the control side of 10 patients. After the simulation of talar tilt correction, talofibular impingement (overlap) occurred in all 30 patients with a larger extent in the severe talar tilt subgroup (p < .001). Conclusion: Talofibular impingement by lateral gutter osteophytes is closely related to increased talar tilt in patients with incongruent varus ankle osteoarthritis. Therefore, lateral gutter osteophytes should be resected to stabilize mortise and improve clinical outcomes.

Comparison of the kinematics, repeatability, and reproducibility of five different multi-segment foot models

BACKGROUND

Multi-segment foot models (MFMs) for assessing three-dimensional segmental foot motions are calculated via various analytical methods. Although validation studies have already been conducted, we cannot compare their results because the experimental environments in previous studies were different from each other. This study aims to compare the kinematics, repeatability, and reproducibility of five MFMs in the same experimental conditions.

METHODS

Eleven healthy males with a mean age of 26.5 years participated in this study. We created a merged 29-marker set including five MFMs: Oxford (OFM), modified Rizzoli (mRFM), DuPont (DFM), Milwaukee (MiFM), and modified Shriners Hospital for Children Greenville (mSHCG). Two operators applied the merged model to participants twice, and then we analysed two relative angles of three segments: shank-hindfoot (HF) and hindfoot-forefoot (FF). Coefficients of multiple correlation (CMC) and mean standard errors were used to assess repeatability and reproducibility, and statistical parametric mapping (SPM) of the t-value was employed to compare kinematics.

RESULTS

HF varus/valgus of the MiFM and mSHCG models, which rotated the segment according to radiographic or goniometric measurements during the reference frame construction, were significantly more repeatable and reproducible, compared to other models. They showed significantly more dorsiflexed HF and plantarflexed FF due to their static offset angles. DFM and mSHCG showed a greater range of motion (ROM), and some models had significantly different FF points of peak angle.

CONCLUSIONS

Under the same conditions, rotating the segment according to the appropriate offset angle obtained from radiographic or goniometric measurement increased reliability, but all MFMs had clinically acceptable reliability compared to previous studies. Moreover, in some models, especially HF varus/valgus, there were differences in ROM and points of peak angle even with no statistical difference in SPM curves. Therefore, based on the results of this study, clinicians and researchers involved in the evaluation of foot and ankle dysfunction need an understanding of the specific features of each MFM to make accurate decisions.

A functional genomics screen identifying blood cell development genes in Drosophila by undergraduates participating in a course-based research experience

Undergraduate students participating in the UCLA Undergraduate Research Consortium for Functional Genomics (URCFG) have conducted a two-phased screen using RNA interference (RNAi) in combination with fluorescent reporter proteins to identify genes important for hematopoiesis in Drosophila. This screen disrupted the function of approximately 3500 genes and identified 137 candidate genes for which loss of function leads to observable changes in the hematopoietic development. Targeting RNAi to maturing, progenitor, and regulatory cell types identified key subsets that either limit or promote blood cell maturation. Bioinformatic analysis reveals gene enrichment in several previously uncharacterized areas, including RNA processing and export and vesicular trafficking. Lastly, the participation of students in this course-based undergraduate research experience (CURE) correlated with increased learning gains across several areas, as well as increased STEM retention, indicating that authentic, student-driven research in the form of a CURE represents an impactful and enriching pedagogical approach.

Nanopore 16S Amplicon Sequencing Enhances the Understanding of Pathogens in Medically Intractable Diabetic Foot Infections

Diabetic foot infections (DFIs) cause substantial morbidity and mortality. The mainstay of the treatment is empiric antibiotics and surgical debridement in severe cases. In this study, we performed nanopore 16S rDNA sequencing from the debridement specimens of DFIs. Fifty-four surgical debridement specimens obtained from 45 patients with medically intractable DFI were included. The 16S rDNA PCR was performed on each specimen, and Nanopore sequencing was performed for up to 3 h. The reads were aligned to the BLAST database, and the results were compared with conventional culture studies. The 16S sequencing results revealed that the majority of the DFIs (44 of 54, 81.5%) were polymicrobial infections. All bacteria isolated by conventional culture studies were detected by 16S sequencing. Several anaerobes (Prevotella, Finegoldia, Anaerococcus, Bacteroides) were commonly identified by 16S sequencing but were frequently missed by culture studies. In many cases, certain bacteria only revealed by the 16S sequencing were more abundant than the bacteria isolated by the culture studies. In conclusion, nanopore 16S sequencing was capable of pathogen identification in DFIs and has many advantages over conventional culture studies. Nanopore 16S sequencing enables a comprehensive understanding of the bacteria involved in DFIs.

The difference of in-shoe plantar pressure between level walking and stair walking in healthy males

Stair walking is more demanding locomotion than level walking and can aggravate discomfort of the foot. The purpose of this study is to analyze plantar pressure distribution and pressure patterns during gait cycle at stair walking compared to level walking. Thirty-five healthy males with 23.4 ± 2 years old were included in this study after examining normality. They performed level walking, stair ascending, and descending in same type of shoes. Measurements of in-shoe plantar pressure including peak pressure, pressure-time integral were done by Pedar-X system, masked 7 regions. Also, pressures in each region throughout the gait cycle were analyzed from each type of walking. Statistical analysis was performed using repeated measure one way analysis of variance. Peak pressure in all regions except for the midfoot was higher during level walking than stair walking. Pressure-time integral in the forefoot, midfoot during stair ascending, and the forefoot during stair descending was higher than level walking. In gait cycle, first peak was produced in the heel and the second peak was produced in the hallux during level walking, whereas during stair ascent, the heel and midfoot were in first peak, and the second peak was in the hallux. During stair descent, the first peak were in the forefoot and the midfoot, and the second peak was in the forefoot. In healthy young male adults, forefoot and midfoot are significant regions in the way that they have higher pressure burdens than other foot regions during stair walking.

Calcifying characteristics of peripheral vascular smooth muscle cells of chronic kidney disease patients with critical limb ischemia

The role of vascular smooth muscle cells (VSMCs) in vascular calcification, which is related to chronic kidney disease (CKD), has been studied in greater detail in the major arteries relative to the peripheral arteries. We compared the calcifying characteristics of peripheral VSMCs relative to non-pathologic major VSMCs in patients with severe peripheral artery disease (PAD). We isolated peripheral VSMCs from the posterior tibial artery of 10 patients with CKD who underwent below-knee amputation for critical limb ischemia (CLI). Using normal human aortic VSMCs as a control group, we cultured the cells in normal and high phosphate media for 10 days, and subsequently tested by immunofluorescence staining. We compared the calcification levels between the two groups using various assays, tests for cell viability, and scanning electron microscopy. As a result, calcification of pathologic peripheral VSMCs increased significantly with time (p = 0.028) and was significantly higher than that in human aortic VSMCs in calcium assays (p = 0.043). Dead cells in the pathologic VSMC group were more distinct in high phosphate media than in human aortic VSMCs. In conclusion, VSMCs from the peripheral artery of patients with severe CKD and CLI who underwent amputation surgery showed marked calcifying characteristics compared to normal human aortic VSMCs.

Change in intersegmental foot and ankle motion after a high tibial osteotomy in genu varum patients

High tibial osteotomy (HTO) is a well-established treatment for medial compartment knee osteoarthritis (OA), which shifts the weight-bearing axis from the medial to the lateral side of the knee. As the adjacent ankle joint may be directly affected by the change in biomechanics, this study aimed to evaluate the change in the intersegmental foot and ankle motion after HTO in patients with genu varum. The study included 24 patients who underwent HTO, and 48 older healthy participants as a control group. Segmental foot kinematics were evaluated using a 3D multisegment foot model, and gait data of temporal and spatial parameters were obtained. After HTO, normalized stride length significantly increased with a tendency for increases in gait speed. In hallux kinematics relative to the forefoot, the sagittal motions of both the patients and the control group were similar throughout the majority of the gait cycle. In forefoot kinematics relative to the hindfoot, the pre-HTO state revealed significant pronation throughout the gait cycle, while the post-HTO state showed a similar position and motion to the control group. In hindfoot kinematics relative to the tibia, coronal motions of the pre-HTO state showed supination throughout the gait cycle, while supination during the stance phase decreased after HTO. Genu varum patients with medial compartment knee OA showed different gait parameters and intersegmental motion during gait when compared with age- and gender-matched controls. The effect of HTO was demonstrated by the normalization of midfoot compensation in patients with genu varum.

Inter-segmental foot kinematics during gait in elderly females according to the severity of hallux valgus

The objective of this study was to find the effect of hallux valgus (HV) deformity on the inter-segmental motion of the foot using an MFM with a 15-marker set (DuPont Foot Model, DuFM) in comparison with age and sex controlled healthy adults. Fifty-eight female symptomatic HV patients and 50 female asymptomatic older female volunteers were included in this study. According to the radiographic hallux valgus angle (HVA), the study population was divided into severe HV (SHV, HVA ≥ 40°, n = 25), moderate HV (MHV, 20° ≤ HVA < 40°, n = 47), and control (CON, n = 36). MHV group was divided into symptomatic MHV group (S-MHV, n = 33) and asymptomatic MHV group (A-MHV, n = 14) according to the symptoms associated with HV. For temporal parameters, gait speed and stride length were diminished according to the severity of HV deformity. Sagittal range of motion of hallux and hindfoot decreased significantly in SHV group. Loss of push-off during the preswing phase was observed and forefoot adduction motion during terminal stance was decreased in SHV group. In a subgroup analysis of MHV, asymptomatic HV minimally affects gait and inter-segmental motion during gait. HV deformity affects gait parameters and inter-segmental motion of the foot during gait in proportion to the severity of the deformity. However, the effect of MHV itself on foot kinematics might be limited while pain or arthritic change of the joint might cause changes in gait in patients with symptomatic HV.

Pneumatic AFO Powered by a Miniature Custom Compressor for Drop Foot Correction

For active AFO applications, pneumatic remote transmission has advantages in minimizing the mass and complexity of the system due to the flexibility in placing pneumatic components and providing high back-drivability via simple valve control. However, pneumatic systems are generally tethered to large stationary air compressors, which greatly limit the practical daily usage. In this study, we implemented a wearable custom compressor that can be worn at the trunk of the body and can generate up to 1050 kPa of pressurized air to power an unilateral active AFO for dorsiflexion (DF) assistance of drop-foot patients. In order to minimize the size and weight of the custom compressor, the compression rate of the custom compressor was optimized to the rate of consumption required to power the active AFO. The finalized system can provide a maximum assistive torque of 9.8 Nm at a functional frequency of 1 Hz and the average resistive torque during free movement was 0.03 Nm. The system was tested for five hemiplegic drop-foot patients. The proposed system showed an average improvement of 12.3° of ankle peak dorsiflexion angle during the mid to late swing phase.

Prevalence of Accessory Bones and Tarsal Coalitions Based on Radiographic Findings in a Healthy, Asymptomatic Population

Background

Accessory bones and tarsal coalitions are the most common developmental variations of the foot and ankle. However, their clinical implications are not well understood because there is no established prevalence data in the normal population and the reported prevalence varies widely. Therefore, we aimed to investigate the incidence of accessory ossicles and tarsal coalitions in a healthy, asymptomatic Korean population.

Methods

A total of 448 healthy, asymptomatic participants (224 men and 224 women; 896 feet) were enrolled and stratified by age and sex. To investigate the presence of accessory bones and tarsal coalitions in the foot and ankle, we obtained the weight-bearing standing radiographs (anteroposterior and lateral views) from each participant.

Results

Accessory ossicles were found in 49.2% of the healthy, asymptomatic Korean adults. The prevalence of accessory bones in adults was the highest with 34% for the accessory navicular, 5.8% for the os trigonum, 3.9% for the os peroneum, and 1.7% for the os subfibulare. The prevalence of tarsal coalitions in adults was 0.4% and that of symphalangism was 16% for the fourth toe and 80.6% for the fifth toe. The frequency of the accessory navicular and fifth toe symphalangism was significantly higher in women. Most of the accessory navicular and fourth and fifth toe symphalangism were bilateral, whereas the os subfibulare was mostly unilateral.

Conclusions

The prevalence of accessory bones and tarsal coalitions in the healthy, asymptomatic Korean population showed some variation according to age and sex.

Entropy production and fluctuation theorems on complex networks

Entropy production (EP) is a fundamental quantity useful for understanding irreversible process. In stochastic thermodynamics, EP is more evident in probability density functions of trajectories of a particle in the state space. Here, inspired by a previous result that complex networks can serve as state spaces, we consider a data packet transport problem on complex networks. EP is generated owing to the complexity of pathways as the packet travels back and forth between two nodes along the same pathway. The total EPs are exactly enumerated along all possible shortest paths between every pair of nodes, and the functional form of the EP distribution is proposed based on our numerical results. We confirm that the EP distribution satisfies the detailed and integral fluctuation theorems. Our results should be pedagogically helpful for understanding trajectory-dependent EP in stochastic processes and exploring nonequilibrium fluctuations associated with the entanglement of dividing and merging among the shortest pathways in complex networks.

Morphological Characteristics of Os Subfibulare Related to Failure of Conservative Treatment of Chronic Lateral Ankle Instability

BACKGROUND

The os subfibulare is usually asymptomatic and found incidentally on radiographs. However, sometimes it may cause subfibular pain and may be associated with chronic lateral ankle instability (CLAI). We hypothesized that os subfibulare could interrupt the talofibular space causing impingement, resulting in chronic pain and functional instability around the lateral malleolus. The purposes of this study were to analyze morphologic characteristics of os subfibulare, and to evaluate the clinical significance of the os subfibulare in patients with CLAI.

METHODS

Between November 2011 and April 2015, 70 patients who had both computed tomography (CT) and magnetic resonance imaging (MRI) among 252 patients who visited our hospital with the symptom of lateral ankle instability were included in this study. The location of the ossicle was classified into 3 zones in reference to the attachment site of the lateral ankle ligaments. The impingement was classified into 2 groups according to the presence of talofibular encroachment. Digital radiographs were used to measure the ossicle width and shape determined by the length and width on an magnetic resonance (MR) image.

RESULTS

The most common shape of ossicles was oval, and the most common location of ossicles was at the anterior talofibular ligament (ATFL) attachment site. Sixty-one percent of patients showed talofibular impingement on coronal MR images. In 48 cases, the dimension of fibula plus os subfibulare was larger than that of the contralateral normal fibula. The larger size and talofibular impingement of the ossicle were associated with greater need for operative treatment in patients with ankle instability.

CONCLUSION

The morphologic analysis of the os subfibulare revealed that there might be impingement of the talofibular space by the ossicle in some patients. We suggest that morphologic characteristics of the os subfibulare should be considered when selecting treatment options in patients with CLAI and os subfibulare.

LEVEL OF EVIDENCE

Level III, retrospective comparative series.

Quantitative evaluation of gait features after total knee arthroplasty: Comparison with age and sex-matched controls

BACKGROUND

Gait function after total knee arthroplasty (TKA) is suboptimal. However, quantified analysis with comparing a control group is lacking.

RESEARCH QUESTION

The aims of this study were 1) to compare the gait before and after TKA and 2) to compare postoperative gait to that of an age-sex matched control group.

METHODS

This study consisted of 46 female and 38 male patients with end-stage knee osteoarthritis who underwent bilateral TKA, and 84 age- and sex-matched controls without knee pain and osteoarthritis. Seven gait parameters, including lower extremity alignment, knee adduction moment (KAM), knee flexion angle, external knee flexion moment, hip adduction angle, external hip adduction moment, and the varus-valgus arc during the stance phase, were collected using a commercial opto-electric gait analysis system. Principal component analysis was used for data processing and the standardized mean differences (SMDs) of the principal component scores were compared.

RESULTS

The most significant gait change after TKA was the alignment (SMD 1.62, p < 0.001). The average stance phase alignment changed from varus 7.3° to valgus 0.5°. The second significant change was a decrease of the KAM (SMD 1.08, p < 0.001). These two features were closely correlated (r = 0.644, p < 0.001). The gait feature that differed most from the controls was the varus-valgus arc during the stance phase (SMD 1.68, p < 0.001), which was constrained by 31% after TKA (p < 0.001) and was only 37% compared to the controls (p < 0.001).

SIGNIFICANCE

Improvement in gait after TKA was obtained through alignment correction. However, TKA significantly constrained coronal knee motion. TKA improved gait suboptimally; the gait was significantly different from that of controls.

Morphological Characteristics of Os Subfibulare Related to Failure of Conservative Treatment of Chronic Lateral Ankle Instability

BACKGROUND

The os subfibulare is usually asymptomatic and found incidentally on radiographs. However, sometimes it may cause subfibular pain and may be associated with chronic lateral ankle instability (CLAI). We hypothesized that os subfibulare could interrupt the talofibular space causing impingement, resulting in chronic pain and functional instability around the lateral malleolus. The purposes of this study were to analyze morphologic characteristics of os subfibulare, and to evaluate the clinical significance of the os subfibulare in patients with CLAI.

METHODS

Between November 2011 and April 2015, 70 patients who had both computed tomography (CT) and magnetic resonance imaging (MRI) among 252 patients who visited our hospital with the symptom of lateral ankle instability were included in this study. The location of the ossicle was classified into 3 zones in reference to the attachment site of the lateral ankle ligaments. The impingement was classified into 2 groups according to the presence of talofibular encroachment. Digital radiographs were used to measure the ossicle width and shape determined by the length and width on an magnetic resonance (MR) image.

RESULTS

The most common shape of ossicles was oval, and the most common location of ossicles was at the anterior talofibular ligament (ATFL) attachment site. Sixty-one percent of patients showed talofibular impingement on coronal MR images. In 48 cases, the dimension of fibula plus os subfibulare was larger than that of the contralateral normal fibula. The larger size and talofibular impingement of the ossicle were associated with greater need for operative treatment in patients with ankle instability.

CONCLUSION

The morphologic analysis of the os subfibulare revealed that there might be impingement of the talofibular space by the ossicle in some patients. We suggest that morphologic characteristics of the os subfibulare should be considered when selecting treatment options in patients with CLAI and os subfibulare.

LEVEL OF EVIDENCE

Level III, retrospective comparative series.

Foot and Ankle Radiographic Parameters in Korean Adults Vary by Sex and Age

Although many radiographic measurements of the foot and ankle have been used, reference values for normal functional groups are rarely reported. These can change according to sex and age; therefore, this study aimed to: (1) determine reference values for radiographic foot and ankle angles in an asymptomatic healthy Korean population, and (2) compare differences in the measurements according to sex and age. A total of 200 healthy volunteers were recruited, including 100 young adults (50 males, 50 females) aged 20 to 35 years, and 100 older adults (50 males, 50 females) aged 60 to 69 years. Weightbearing ankle anteroposterior views, talar tilt, and tibiotalar angles were measured. On the weightbearing foot anteroposterior views, the hallux valgus, hallux interphalangeal, and talo-first metatarsal angles were measured. On the weightbearing lateral foot views, the calcaneal pitch, lateral talo-calcaneal, lateral talo-first metatarsal, and lateral calcaneo-first metatarsal angles were measured. Values were stratified by sex and age, and statistically compared. The hallux valgus, calcaneal pitch, and lateral calcaneo-first metatarsal angles were affected by both sex and age; the hallux interphalangeal angle was affected by age and the lateral talo-first metatarsal angle by sex. We presented reference values for foot and ankle radiographic measurements in a healthy Korean population; several radiographic indices varied significantly by sex or age, which were grossly similar to previous studies based on white race. The study data can serve as a basis for evaluation of foot and ankle disorders.

Repeatability of a Multi-segment Foot Model with a 15-Marker Set in Normal Children

Background

The use of three-dimensional multi-segment foot models (3D MFMs) is increasing since they have superior ability to illustrate the effect of foot and ankle pathologies on intersegmental motion of the foot compared to single-segment foot model gait analysis. However, validation of the repeatability of the 3D MFMs is important for their clinical use. Although many MFMs have been validated in normal adults, research on MFM repeatability in children is lacking. The purpose of this study is to validate the intrasession, intersession, and interrater repeatability of an MFM with a 15-marker set (DuPont foot model) in healthy children.

Methods

The study included 20 feet of 20 healthy children (10 boys and 10 girls). We divided the participants into two groups of 10 each. One group was tested by the same operator in each test (intersession analysis), while the other group was tested by a different operator in each test (interrater analysis). The multiple correlation coefficient (CMC) and intraclass correlation coefficient (ICC) were calculated to assess repeatability. The difference between the two sessions of each group was assessed at each time point of gait cycle.

Results

The intrasession CMC and ICC values of all parameters showed excellent or very good repeatability. The intersession CMC of many parameters showed good or better repeatability. Interrater CMC and ICC values were generally lower for all parameters than intrasession and intersession. The mean gaps of all parameters were generally similar to those of the previous study.

Conclusions

We demonstrated that 3D MFM using a 15-marker set had high intrasession, intersession, and interrater repeatability in the assessment of foot motion in healthy children but recommend some caution in interpreting the hindfoot parameters.