Category:
Ankle Arthritis; Hindfoot
Introduction/Purpose:
Dome shaped supramalleolar osteotomies are a well-established treatment option for correcting ankle deformity. However, the procedure remains ...technically demanding and is limited by a two-dimensional (2-D) radiographic planning of a three-dimensional (3-D) deformity. Therefore, we implemented a weight-bearing CT-scan (WBCT) to plan a 3-D deformity correction using patient specific guides.
Methods:
A 3-D guided dome shaped supramalleolar osteotomy was performed to correct ankle varus deformity in a cohort of 5 patients with a mean age of 53,8 years (range: 47-58). WBCT images were obtained to generate 3-D models, which enabled a deformity correction using patient specific guides. These technical steps are outlined and associated with a retrospective analysis of the clinical outcome using the EFAS score, Foot and Ankle Outcome Score (FAOS) and Visual Analog Pain scale (VAS).
Radiographic assessment was performed using the tibial anterior surface angle (TAS), tibiotalar angle (TTS), talar-tilt angle (TTA), hindfoot angle (HA), tibial lateral surface angle (TLS) and tibial rotation angle (TRA).
Results:
The mean follow-up was 40,8 months (range 8-65) and all patients showed improvements in the EFAS score, FAOS and VAS (p < 0.05). A 3-month postoperative WBCT confirmed healing of the osteotomy site and radiographic improvement of the TAS, TTS and HA (p<0.05), but the TTA and TRA did not change significantly (p>0.05).
Conclusion:
Dome shaped supramalleolar osteotomies using 3-D printed guides designed on WBCT, are a valuable option in correcting ankle varus deformity and mitigates the technical drawbacks of free-hand osteotomies.
Objective
The role of the syndesmotic ankle ligaments as extrinsic stabilizers of the distal tibiofibular joint (DTFJ) has been studied extensively in patients with high ankle sprains (HAS). However, ...research concerning the fibular incisura as intrinsic stabilizer of the DTFJ has been obscured by a two-dimensional assessment of a three-dimensional structure. Therefore, we aimed to compare the morphometry of the incisura fibularis between patients with HAS and a control group using three-dimensional radiographic techniques.
Materials and methods
Fifteen patients with a mean age of 44 years (SD = 15.2) diagnosed with an unstable HAS and twenty-five control subjects with a mean age of 47.4 years (SD = 6.5) were analyzed in this retrospective comparative study. The obtained CT images were converted to three-dimensional models, and the following radiographic parameters of the incisura fibularis were determined using three-dimensional measurements: incisura width, incisura depth, incisura height, incisura angle, incisura width-depth ratio, and incisura-tibia ratio.
Results
The mean incisura depth (M = 4.7 mm, SD = 1.1 mm), incisura height (M = 36.1 mm, SD = 5.3 mm), and incisura angle of the control group (M = 137.2°, SD = 7.9°) differed significantly from patients with a HAS (resp., M = 3.8 mm, SD = 1.1 mm; M = 31.9 mm, SD = 3.2 mm; M = 143.2°, SD = 8.3°) (
P <
0.05). The incisura width, incisura width-depth ratio, and incisura-tibia ratio demonstrated no significant difference (
P >
0.05).
Conclusion
Our three-dimensional comparative analysis has detected a shallower and shorter fibular incisura in patients with HAS. This distinct morphology could have repercussion on the intrinsic or osseous stability of the DTFJ. Future prospective radiographic assessment could determine to what extend the fibular incisura morphology contributes to syndesmotic ankle injuries caused by high ankle sprains.
Category:
Ankle; Basic Sciences/Biologics; Hindfoot
Introduction/Purpose:
Abnormal Hindfoot Alignment (HA) has been correlated with increased complication rates in ankle fusion or replacement. ...Altered Bone Mineral Density (BMD) due to abnormal stress distribution could be predisposing factor for those unwanted outcomes. The objective of this study was to assess spatial distribution of BMD around the ankle joint in patients with normal or abnormal HA using cone beam Weight Bearing CT.
Methods:
Retrospective comparative study including 81 ankles allocated into 3 groups based on the Foot Ankle Offset (FAO): 27 normal (0%5%). groups were comparable by age (p=0.967), Body Mass Idex (p=0.669), sex (p=0.820) and side (p=0.708). Semi- automatic segmentation (BoneLogic, Disior) was applied to identify bones. Tibia and talus were digitally compartmented in medial (M) and lateral (L) volumes relative to the median sagittal plane. Mean Hounsfield Unit (HU) value per compartment was used to assess BMD and to calculate the Medial over Lateral HU ratio (M/L-HU). Comparisons among the three groups were performed using one-way ANOVA, Kruskal-Wallis and Chi2 tests.
Results:
Mean +- standard deviation HU values in the compartments in normal cases were 495.2+-110 (medial tibia), 495.6+- 108.1 (lateral tibia), 368.9+-80.3 (medial talus), 448.2+-90.6 (lateral talus) and 686.7+-120.4 (fibula). Upon comparison of the mean BMD value for each compartment in the three groups, the difference did not achieve statistical significance. Conversely, the tibia HU-M/L ratio (0.88+-0.14 in valgus cases, 0.99 +- 0.08 in normally-aligned cases and 1.04+-0.08 in varus cases) and the talar HU- M/L ratio (0.68+-0.18 in valgus cases, 0.82+-0.08 in normally-aligned cases and 0.96+-0.20 in varus cases) were significantly different in the three groups (p<0.001).
Conclusion:
We found that the BMD in distal tibia, fibula and the talus varies with hindfoot alignment. The increased HU medio- lateral ratio in varus cases was consistent with a greater medial bone density in the tibia and talus, while the decreased ratio found in valgus cases suggested a more lateral concentration in both bones. This data supports the role of WBCT in analyzing BMD distribution. This method could be clinically useful in ankle OA to evaluate bone quality for such considerations as surgical indications or implant positioning.
Category:
Trauma; Ankle
Introduction/Purpose:
Forced external rotation is hypothesized as the key mechanism of syndesmotic ankle injuries, inducing a three-dimensional deviation from the normal ...distal tibiofibular joint alignment. These lesions, especially when subtle, present a deceitful diagnostic challenge. Current diagnostic imaging modalities are impeded by a two-dimensional assessment, without considering ligamentous stabilizers. Accurate diagnosis of syndesmotic lesions should involve 3D weightbearing osseous imaging in combination with - preferably automated- inclusion of patient-specific ligamentous information. Therefore, our aim is two-fold: (1) to construct a three-dimensional articulated statistical shape model of the normal distal tibiofibular joint with inclusion of ligamentous morphometry and (2) to detect differences in predicted syndesmotic ligament length of patients with syndesmotic lesions with respect to normative data.
Methods:
Training data comprised non-weightbearing CT scans from asymptomatic controls (N= 76, Mean age 63 +/- 19 years), weightbearing CT scans from patients with syndesmotic ankle injury (N = 13, Mean Age 35 +/- 15 years) and their weightbearing healthy contralateral side (N = 13). CT scan segmentation was used to generate 3D bone models in the control and patient group. All ankles were aligned based on the tibia. Path and length of the syndesmotic ligaments were predicted using a discrete element model, wrapped around bony contours. Statistical shape model evaluation was based on accuracy, generalization and compactness. The predicted ligament length in patients with syndesmotic lesions was compared to healthy controls by use of two-tailed Two- Sample student's t-test.
Results:
Our presented skeletal shape model described the training data with an accuracy of 0.23 +/- 0.028 mm. Mean prediction accuracy of ligament insertions was 0.53 +/- 0.12 mm. Mean length of the Anterior inferior tibiofibular ligament was 12.26 +- 1.89mm for the control cases, 12.32 +- 1.58 mm for the contralateral cases and 14.13 +- 1.48 mm for the cases with syndesmotic lesions. Statistically significant differences were found between the latter two (95% CI 0.323.29, p = 0.017) There was a significant correlation between presence of syndesmotic injury and the positional alignment between the distal tibia and fibula (r = 0.873, p < 0,001).
Conclusion:
Statistical shape modelling combined with patient-specific ligament wrapping techniques can facilitate the diagnostic workup of syndesmotic ankle lesions under weightbearing conditions. In doing so, an increased anterior tibiofibular distance was detected, corresponding to an 'anterior open-book injury' of the ankle syndesmosis as a result of anterior inferior tibiofibular ligament elongation/rupture (Figure 1).
Category:
Ankle; Basic Sciences/Biologics; Hindfoot
Introduction/Purpose:
Abnormal Hindfoot Alignment (HA) has been correlated with increased failure rates in ankle fusion or replacement for ...osteoarthritis (OA). An altered stress distribution in the surrounding bone and abnormal Bone Mineral Density (BMD) around the native ankle may be predisposing factors for those unwanted outcomes. Cone Beam Weight Bearing CT (WBCT) has recently been used to investigate BMD and to correlate the localization of periprosthetic cysts and alignment in ankle arthroplasty. The objective of this study was to assess the spatial distribution of BMD around the ankle joint in patients with normal or abnormal HA. We hypothesized that BMD would be evenly distributed in normally-aligned ankles whilst increased medially in varus and laterally in valgus configurations.
Methods:
In this retrospective comparative Level III study, 60 ankles (41 adults),without any trauma or surgery affecting HA, with WBCT datasets (PedCat, Curvebeam LLC, PA-USA) were allocated to 3 groups (comparable by age, p=0.79; BMI, p=0.24; and side, p=0.93), based on the Foot Ankle Offset (FAO) values: 20 normal (0%-2), 20 varus (FAO< 0%; 35% female, age 48.8+-13 years, BMI 26.2+-2.9 kg.m-2), and 20 valgus (FAO>5%; 40% female, age 58.9+-14.6 years, BMI 28.6+-4.2 kg.m-2). Semi-Automatic Segmentation (BoneLogic, Disior Oy, Helsinki-Finland) was applied to identify bones of interest. The tibia and talus were digitally compartmented in medial (M) and lateral (L) volumes relative to the median sagittal plane. Mean Hounsfield Unit (HU) value per compartment was used to assess BMD. The primary outcome measure was the Medial over Lateral HU ratio (M/L-HU). Comparisons were performed using one-way ANOVA, Kruskal-Wallis and Chi2 tests.
Results:
All values of BMD were normally distributed but M/L-HU ratios were not. Mean +- standard deviation HU values in the compartments in normal cases were 523+-103 (medial tibia), 519+-115 (lateral tibia) 421+-81 (medial talus), 470+-92 (lateral talus) and 725+-109 (fibula). The mean BMD was significantly lower in all compartments in valgus cases compared to normal (all p<0.05). It was decreased in valgus vs varus in the talus (p<0.04), specifically in the medial compartment (p<0.01). The tibia M/L- HU ratio was decreased in valgus vs normal (0.87+-0.16 vs 1.01+-0.07; p=0.001) and vs varus (1.04+-0.09; p<0.001). The talus M/L-HU ratio was increased in varus cases vs normal (1+-0.22 vs 0.83+-0.09; p<0.01) and valgus (0.07+-0.19; p<0.001).
Conclusion:
We found that BMD in distal tibia, fibula and the talus varies with hindfoot alignment. In valgus configuration, all bone compartments were less dense compared to normal and varus. The medio-lateral ratio increased in the tibia and in the talus in varus cases, suggesting medial concentration of bone, and decreased in valgus cases, suggesting a more lateral concentration. This data supports the role of WBCT in analyzing BMD distribution. This method could be clinically useful in ankle OA to evaluate bone quality for such considerations as surgical indications or implant positioning.
The majority of patients with an osteochondral lesion of the talus (OLT) report a history of trauma. Therefore, it is important to assess for concomitant ankle instability when dealing with patients ...with a symptomatic OLT. The History; Alignment; Ligaments; Others "(HALO)" approach can be a helpful tool in the evaluation of patients with an OLT. If conservative treatment fails, surgery may be indicated. Although there is a lack of comparative studies investigating the effect of stabilization procedures on cartilage repair, we believe that addressing instability is a key factor in improving patient outcome.
Category:
Ankle; Hindfoot; Midfoot/Forefoot; Other
Introduction/Purpose:
The same Consensus that proposed a new nomenclature for Flatfoot, Progressive Collapsing Foot Deformity (PCFD), also ...introduced a new classification system for the disease. The idea of staging was supplemented by the construction of a system combining deformity classes and its flexibilities, using clinical and radiographic signs. The capacity of the weight-bearing computed tomography (WBCT) in evaluating PCFD and all components of peritalar subluxation has been established. The objective of this study was to compare PCFD classifications performed utilizing clinical and conventional radiographs (CR) findings with classifications established using clinical and WBCT findings. We hypothesized that evaluations considering WBCT would significantly change PCFD classifications, portraying a different picture of the disease.
Methods:
This retrospective IRB-approved case-control diagnostic study evaluated 89 consecutive PCFD feet (84 patients) with different presentations of the disease. Three fellowship-trained foot and ankle surgeons performed chart reviews and CR evaluations, determining PCFD classifications for the studied subjects. After a two-week washout period, the sequence was randomized, and a new classification was executed using clinical data and WBCT assessment. One of the readers repeated the WBCT evaluation two weeks later for intrarater reliability purposes. Assessments included the presence or absence of classes, such as hindfoot valgus (A), midfoot abduction/sinus tarsi impingement (B), medial column instability (C), subtalar joint subluxation/subfibular impingement (D), and valgus of the ankle joint (E) as well as flexibility (1) and rigidity (2) of existing deformities. Fleiss kappa was used for interrater and Cohen's kappa for intrarater agreements. Differences between studied groups were determined by distribution comparison.
Results:
Mean BMI and age were 54.4 (+-17.1) and 33.6 (+-7.6) respectively. Interrater reliability was found to be moderate (0.55) and intrarater to be excellent (0.98). Evaluation using CR produced 22.8% of 1ABC, 13% of 1AC, 8,7% of 1ABCD and 7% of 2EABCD as most prevalent classifications. WBCT assessment found 31.5% of 1ABC, 11.2% of 1ABCD, 10.1% of 2ABCDE and 5.6% 1ABCDE. Class A was the most frequent component in CR (93.5%) and WBCT (94.5%). Class B had a higher prevalence in WBCT (94.38%) than in CR (71.7%) as well as Classes C (89.9% and 88.0%), D (44.9% and 29.3%) and E (31.5% and 23.9%). The percentage of combined flexible (1) and rigid (2) deformities was also higher in the WBCT evaluation (39.3% compared to 35.8%).
Conclusion:
As the new classification proposes the combination of different PCFD components to better support clinical decisions, proper identification of the classes is mandatory for a complete diagnosis. WBCT showed a different rate of deformity recognition, which increased the incidence of all classes, especially B (midfoot abduction/sinus tarsi impingement) and D (peritalar subluxation/subfibular impingement). An excellent intrarater agreement was found, which infers reliability of patient assessment combining clinical and WBCT evaluation. The obtained information could help providers to enhance comprehension of the disease and to supply patients with the most precise individual care.
Category:
Ankle; Hindfoot; Other
Introduction/Purpose:
Peritalar subluxation (PTS) of the hindfoot is a critical finding in Progressive Collapsing Foot Deformity (PCFD). Subluxation of the middle ...facet and sinus tarsi impingement have recently been shown to represent essential markers of pronounced and potentially progressive deformity. Weightbearing CT (WBCT) imaging and three-dimensional (3D) distance (DM) and coverage maps (CM) allow a complete and accurate assessment of PTS markers across the entire peritalar surface. This prospective comparative study aimed to assess the effectiveness of joint-sparing realignment surgical treatment for flexible PCFD in reducing PTS and to correlate the improvement with patient-reported outcomes (PROs). We hypothesized that surgical treatment would significantly improve PTS markers, mainly decreasing sinus tarsi coverage/impingement and middle facet subluxation, and that this improvement would correlate with increased PROs.
Methods:
In this IRB-approved prospective and comparative study, we enrolled patients with flexible PCFD, no prior surgeries, and failed conservative treatment. Included patients (n=10, 7 females/3 males, mean age 57.2, range 37-74) underwent joint-sparing surgical realignment procedure by a single surgeon. Standing weightbearing CT (WBCT) was completed preoperatively and 3- months postoperatively. Following automatic bone segmentation, 3D distance maps (DMs) of the entire peritalar surface were generated, and coverage of the subtalar joint articular facets (anterior, middle, and posterior) and sinus tarsi were assessed as markers of PTS. Joint coverage was defined as the percentage of articular space where DMs were <5 mm. Coverage Maps (CM) were built highlighting areas of adequate joint interaction (blue), joint subluxation (pink), and impingement (red). PROs were evaluated preoperatively and at the latest follow-up. Differences between preop/postop measurements and PROs were assessed by independent t-tests/Wilcoxon and bivariate analysis. P-values <.05 were considered significant.
Results:
The overall follow-up was 8.2 months (6-13 months). Medial displacement calcaneal osteotomies, lateral column lengthening, and first ray realignment procedures (either Cotton osteotomy or Lapidus) were performed in all patients. Foot and Ankle Offset significantly improved from 10.6% preoperatively to 3.1% postoperatively (p=0.0005), on average. Significant averaged improvement was also observed in anterior facet joint coverage (61.6%), as well as a reduction in sinus tarsi coverage/impingement (-43.2%) (both p<0.001). Middle (19.5%, p=0.08) and posterior facet joint coverage (3.5%, p=0.06) also demonstrated improvements, however not significant. PROs improved significantly on average postoperatively, with the European Foot and Ankle Surgery (EFAS) Score increasing from 3.1 to 7.3 (p=0.02) and the Foot Function Index (FFI) improving from 71.5 to 48.7 (p=0.01). Improvements in EFAS scores and FFI significantly correlated with improvements in middle facet coverage (R2 0.89, p=0.0154) and anterior facet coverage (R2 0.80, p=0.04), respectively.
Conclusion:
Our study was the first to evaluate WBCT 3D distance mapping's role in the assessment of surgical correction of PTS in patients with PCFD. We found significant improvements in subtalar joint anterior facet coverage and sinus tarsi impingement following surgical reconstruction, with a trend to significant improvements in middle and posterior facet joint coverage. More importantly, improvements in middle and anterior facet coverage correlated significantly with improved PROs (EFAS score and FFI, respectively). Based on our study results, optimization of subtalar joint coverage and reduction of PTS should be goals of surgical treatment of PCFD patients.
Category:
Hindfoot; Midfoot/Forefoot
Introduction/Purpose:
The same Consensus that proposed a new nomenclature for Flatfoot, Progressive Collapsing Foot Deformity (PCFD), also introduced a new ...classification system for the disease. The idea of staging was supplemented by the construction of a system combining deformity classes and its flexibilities, using clinical and radiographic signs. The capacity of the weight-bearing computed tomography (WBCT) in evaluating PCFD and all components of peritalar subluxation has been established. The objective of this study was to compare PCFD classifications performed utilizing clinical and conventional radiographs (CR) findings with classifications established using clinical and WBCT findings. We hypothesized that evaluations considering WBCT would significantly change PCFD classifications, portraying a different picture of the disease.
Methods:
This retrospective IRB-approved case-control diagnostic study evaluated 89 consecutive PCFD feet (84 patients) with different presentations of the disease. Three fellowship-trained foot and ankle surgeons performed chart reviews and CR evaluations, determining PCFD classifications for the studied subjects. After a two-week washout period, the sequence was randomized, and a new classification was executed using clinical data and WBCT assessment. One of the readers repeated the WBCT evaluation two weeks later for intrarater reliability purposes. Assessments included presence or absence of classes, such as hindfoot valgus (A), midfoot abduction/sinus tarsi impingement (B), medial column instability (C), subtalar joint subluxation/subfibular impingement (D) and valgus of the ankle joint (E) as well as flexibility (1) and rigidity (2) of existing deformities. Fleiss kappa was used for interrater and Cohen's kappa for intrarater agreements. Differences between studied groups were determined by distribution comparison.
Results:
Mean BMI and age were 54.4 (+-17.1) and 33.6 (+-7.6) respectively. Interrater reliability was found to be moderate (0.55) and intrarater to be excellent (0.98). Evaluation using CR produced 22.8% of 1ABC, 13% of 1AC, 8,7% of 1ABCD and 7% of 2EABCD as most prevalent classifications. WBCT assessment found 31.5% of 1ABC, 11.2% of 1ABCD, 10.1% of 2ABCDE and 5.6% 1ABCDE. Class A was the most frequent component in CR (93.5%) and WBCT (94.5%). Class B had a higher prevalence in WBCT (94.38%) than in CR (71.7%) as well as Classes C (89.9% and 88.0%), D (44.9% and 29.3%) and E (31.5% and 23.9%). The percentage of combined flexible (1) and rigid (2) deformities was also higher in the WBCT evaluation (39.3% compared to 35.8%).
Conclusion:
As the new classification proposes the combination of different PCFD components to better support clinical decisions, proper identification of the classes is mandatory for a complete diagnosis. WBCT showed a different rate of deformity recognition, which increased the incidence of all classes, especially B (midfoot abduction/sinus tarsi impingement) and D (peritalar subluxation/subfibular impingement). An excellent intrarater agreement was found, which infers reliability of patient assessment combining clinical and WBCT evaluation. The obtained information could help providers to enhance comprehension of the disease and to supply patients with the most precise individual care.
Category:
Hindfoot; Midfoot/Forefoot
Introduction/Purpose:
Peritalar subluxation (PTS) of the hindfoot is a critical finding in Progressive Collapsing Foot Deformity (PCFD). Subluxation of the middle ...facet and sinus tarsi recently been shown to represent essential markers of pronounced and potentially progressive deformity. Weightbearing CT (WBCT) imaging and three-dimensional (3D) distancing coverage maps (CM) allow a complete and accurate assessment of PTS markers across the entire peritalar surface. This prospective comparative study aimed to assess the effectiveness of joint-sparing realignment surgical treatment for flexible PCFD in reducing PTS and to correlate the improvement with patient-reported outcomes (PROs). We hypothesized that would significantly improve PTS markers, mainly decreasing sinus tarsi coverage/impingement and middle facet subluxation, and that this improvement would correlate with increased PROs.
Methods:
In this IRB-approved prospective and comparative study, we enrolled patients with flexible PCFD, no prior surgeries, and failed conservative treatment. Included females/3 males, mean age 57.2, range 37-74) underwent joint-sparing surgical realignment procedure by a single surgeon. Standing weightbearing CT (WBCT) was complete 3-months postoperatively.
Following automatic bone segmentation, 3D distance maps (DMs) of the entire peritalar surface were generated, and coverage of the subtalar joint (anterior, middle, and posterior) and sinus tarsi were assessed as markers of PTS. Joint coverage was defined as the percentage of articular space where DMs were <5 mm. CM were built highlighting areas of adequate joint interaction (blue), joint subluxation (pink), and impingement (red). PROs were evaluated preoperatively and at the latest follow-up between preop/postop measurements and PROs were assessed by independent t-tests/Wilcoxon and bivariate analysis. P-values <.05 were considered significant.
Results:
The overall follow-up was 8.2 months (6-13 months). Medial displacement calcaneal osteotomies, lateral column lengthening, and first ray realignment procedure osteotomy or Lapidus) were performed in all patients. Foot and Ankle Offset significantly improved from 10.6% preoperatively to 3.1% postoperatively (p=0.0005), on averaged improvement was also observed in anterior facet joint coverage (61.6%), as well as a reduction in sinus tarsi coverage/impingement (-43.2%) (both p<0.001). Middle posterior facet joint coverage (3.5%, p=0.06) also demonstrated improvements, however not significant. PROs improved significantly on average postoperatively, with the E Ankle Surgery (EFAS) Score increasing from 3.1 to 7.3 (p=0.02) and the Foot Function Index (FFI) improving from 71.5 to 48.7 (p=0.01). Improvements in EFAS scores and FFI s with improvements in middle facet coverage (R2 0.89, p=0.0154) and anterior facet coverage (R2 0.80, p=0.04), respectively.
Conclusion:
Our study was the first to evaluate WBCT 3D distance mapping's role in the assessment of surgical correction of PTS in patients with PCFD. We found significant subtalar joint anterior facet coverage and sinus tarsi impingement following surgical reconstruction, with a trend to significant improvements in middle and posterior facet j importantly, improvements in middle and anterior facet coverage correlated significantly with improved PROs (EFAS score and FFI, respectively).
Significance/Clinical Relevance: Based on our study results, optimization of subtalar joint coverage and reduction of PTS should be goals of surgical treatment of PC
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