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Category: Hindfoot; Midfoot/Forefoot Introduction/ Purpose: Peritalar subluxation (PTS) is a crucial feature of Progressive Collapsing Foot Deformity (PCFD). Surrounding structures assume distinct behaviors, contributing to different disease deformities (classes). One of its most traditional aspects is the midfoot abduction (class B), usually noted by a lateral deviation of distal structures at the talonavicular joint. This finding commonly leads surgeons to perform a lateral column lengthening osteotomy for abduction correction, a complex surgery with potential complications. The first ray's ability to reestablish the tripod and restore the hindfoot by derotating structures under the talus was previously theorized. This study aimed to test the capability of the Lapidus and the Cotton procedures in conjunction with a calcaneus displacement osteotomy (MDCO) to improve midfoot abduction in the setting of a collapsed foot. Methods: In this IRB-approved, prospective cohort study, we analyzed patients undergoing medial column instability surgery and evaluated preoperatively with a weight-bearing CT (WBCT). We included individuals receiving a Lapidus bone block procedure or a Cotton for PCFD or Hallux Valgus (HV). Patients having a lateral column lengthening procedure of any type were excluded. Talonavicular coverage angle (TNCA) was measured as a marker of midfoot abduction. Medial arch collapse and forefoot varus were evaluated by the sagittal talus-first metatarsal angle (TFMA), and the forefoot arch angle (FFA) was measured. Associated procedures and the correction amount (displacement or wedge size) were recorded. Normality was estimated by the Shapiro- Wilk test and comparison among timelines by the one-way ANOVA. A multivariate regression analysis was executed to evaluate which of the measurements influenced abduction improvement. Statistical significance was considered for p-values of less than 0.05. Results: A total of 20 patients (age: 43.85 [19-72], BMI 30.98 [SD: 5.95]) were included, 11 PCFD (55%) and 9 HV (45%) with a mean follow-up of 7.5 months (3-12). Bone block Lapidus was performed in most subjects (90%), and the median wedge used was 9mm (5-12mm). MDCO occurred in 55% of patients. All measured variables had improvement with surgery (TNCA: 23.74 to 10.66, p< 0.0001; FFA: 6.27 to 12.67, p< 0.0001; TFMA: 11.73 to 4.22, p=0.0003). A correlation was found between TNCA improvement and FFA improvement (rs=0.46, p=0.0407), but not among TNCA improvement and TFMA improvement (rs=0.43, p=0.06). The size of the wedge did not strongly influence the TNCA correction (R2=0.016, p=0.0036), an improvement moderately explained by the MDCO amount (R2=0.186, p< 0.0001). Conclusion: This study demonstrated correction of midfoot abduction, translated by the TNCA, in the absence of lateral column lengthening procedures. When evaluating patients submitted to first ray procedures (bone block Lapidus and Cotton) in conjunction with MDCO, an enhancement on the talar head coverage was noted. Variables associated with arch height and forefoot varus (FFA and TFMA) were correlated with the TNCA improvement. Nevertheless, only the MDCO displacement amount and not the size of the used allograft wedge could explain changes in TNCA. The provided data might support surgeons when planning treatment in the PCFD scenario.

Category: Midfoot/Forefoot; Basic Sciences/Biologics; Hindfoot Introduction/Purpose: A recent study published in Nature (Venkadesan et al.) demonstrated that coupling the transverse arch (TA) with the medial longitudinal arch (MLA) significantly increased midfoot intrinsic stiffness. The contribution of the TA is substantial, suggested as the evolutionary advancement providing the foot stiffness required for human bipedalism. Progressive collapsing foot deformity (PCFD) is a complex deformity ultimately resulting in loss of stiffness and collapse of the MLA. The novel understanding of the TA may play a key role in the pathogenesis of this deformity. The objectives of this study were to assess and compare the TA curvature in PCFD and controls and to evaluate its relationship with accepted PCFD measures. We hypothesized that the curvature of the TA will be decreased in PCFD. Methods: A retrospective review was conducted for 32 PCFD and 32 controls. Measurements were performed using weight- bearing CT (WBCT). A novel measurement, the transverse arch plantar (TAP) angle, was designed to directly measure the TA in both PCFD (Figure 1a) and controls (Figure 1b). TA curvature was calculated using the equation described by Venkadesan et al. (Figure 6) utilizing width, length (Figure 3a), 3rd metatarsal thickness (Figure 3b), and 4th metatarsal torsion (Figure 4a, 4b). Finally, uni- and multivariate analyses were performed to analyze the relationship between the TAP angle, Foot and Ankle Offset (FAO), peritalar subluxation, and measurements associated with PCFD classes: hindfoot moment arm (class A), talonavicular coverage angle (class B), Meary angle (class C), medial facet uncoverage angle (class D), and talar tilt (class E). Normality of different variables was assessed using the Shapiro-Wilk test. Two groups were compared using t-test for normal, and Mann-Whitney for non-normal variables. Results: Measurements of the TAP angle were found to be significantly higher in the PCFD group than the control group with a mean angle of 115.24° (SD 10.68) and 100.76° (SD 7.92) respectively (p

Category: Midfoot/Forefoot; Basic Sciences/Biologics; Hindfoot Introduction/Purpose: The current classification system of progressive collapsing foot deformity (PCFD) is comprised of 5 possible classes that describe different deformity components. Each class is defined by clinical and radiographic findings. These components are ostensibly independent from one another during evaluation and treatment. However, PCFD is understood to be a complex, three-dimensional deformity occurring in many regions along the foot and ankle. The question remains whether a deformity in one area impacts other areas. The objective of this study is to assess how each one of the classes is influenced by other classes by evaluating each associated angular measurement. We hypothesized that positive and linear correlations would occur for each class with at least one other class and that this influence would be high. Methods: In this IRB-approved retrospective case-control study, we assessed 32 feet diagnosed with PCFD and 28 controls matched on gender, BMI and age. All measurements were performed using weight-bearing CT (WBCT) scans and completed by two foot and ankle surgeons. The classes and their associated radiographic measurements were defined as follows: Class A (hindfoot valgus) measured by the hindfoot moment arm (HMA), class B (midfoot abduction) measured by the talonavicular coverage angle (TNCA), class C (medial column instability) measured by the talus-first metatarsal (Meary) angle, class D (peritalar subluxation) measured by the medial facet uncoverage (MFU), and class E (ankle valgus) measured using the talar tilt angle (TTA). Multivariate analyses were completed comparing each class measurement to the other classes. Data were checked for multicollinearity with the Belsley-Kuh-Welsch technique. Heteroskedasticity and normality of residuals were assessed respectively by the Breusch-Pagan test and the Shapiro-Wilk test. A p-value

Category: Ankle; Ankle Arthritis; Hindfoot; Other Introduction/Purpose: Total ankle replacement (TAR) has been shown as a viable surgical option to reduce pain, improve function, and preserve ankle joint range of motion in patients with Ankle osteoarthritis (AO). Standard anterior approach TAR capability in correcting deformities is already established by several studies. However, there is a paucity of literature evaluating patient outcomes as well as the potential to correct alignment using a lateral approach TAR. Therefore, the primary objective of this study was to assess the capability of lateral trans-fibular approach TAR in correcting coronal and sagittal plane deformity and secondarily to report the ability to improve patient-reported outcomes (PROs) following lateral TAR. Methods: This IRB-approved, retrospective comparative study included 14 consecutive patients that underwent lateral trans- fibular approach TAR for end-stage AO. Average age and BMI were 63.9 years (range 43-83) and 32.7 kg/m2 (SD 7.5). All patients had received pre- and post-operative weight-bearing CT imaging on the affected foot and ankle. Foot and Ankle Offset (FAO), Talar Tilt Angle (TTA), Hindfoot Moment Arm (HMA), and Lateral Talar Station (LTS) were performed. PROs were collected pre- and post-operatively at the latest clinical follow-up including: PROMIS Global Physical Health score, the Tampa Scale of Kinesiophobia (TSK), the European Foot and Ankle Society (EFAS) score, the Pain Catastrophizing Scale (PCS) and the Foot and Ankle Ability Measure (FAAM) Daily Living Score. One-way ANOVA and Wilcoxon tests were used for comparison at each interval time period. A multivariate regression analysis was then performed to evaluate the association between change in alignment and improvements of PROs. Results: Three of 14 patients (21.4%) underwent a concomitant osseous re-alignment procedure. At an average of 16.1 months (range 11 to 24), all patients demonstrated a significant deformity correction in measurements performed: FAO (7.73% - 3.63%, p=0.031), HMA (10.93mm - 5.10mm, p=0.037), TTA (7.9o - 1.5o, p=0.003), and LTS (5.25mm - 2.83mm, p=0.018). Four of the PROs demonstrated significant improvement postoperatively: TSK (42.7-34.5, p=0.012), PROMIS Global Physical Health (46.1- 54.5, p=0.011), EFAS (5-10.3, p=0.004), and FAAM (60.5-79.7, p=0.04). PROMIS was associated (p=0.0015) with optimization of FAO (p=0.00065) and LTS (p=0.00436), R2 of 0.98). Improvements in TSK were associated with changes in the HMA (p=0.0074), R2 of 0.66. Improvements in FAAM correlated (p=0.048) with improvements in FAO (p=0.023) and TTA (p=0.029), and an R2 of 0.78. Conclusion: In this retrospective comparative cohort study, the results suggest that the lateral trans-fibular TAR can correct different aspects of AO deformity. Clinical benefit was also demonstrated by the impacted PROs, particularly TSK, PROMIS Global Physical Health, EFAS, and FAAM Daily Living. Direct and strong correlations between deformity correction measurements and the significantly improved PROs were found. The obtained data might help surgeons when planning treatment and may serve as the basis for future comparative prospective studies.

Category: Bunion Introduction/Purpose: The minimally invasive Chevron Akin (MICA) osteotomy have been widely used treating hallux valgus (HV). The purpose of this study was to present a case series of patients with severe HV undergoing surgical treatment using the MICA procedure, and to evaluate the clinical and radiographic outcomes Methods: Sixty consecutive feet (52 patients) undergoing MICA for severe HV were included. Patients were assessed pre and postoperatively. Clinically evaluation was realized by visual analogue pain scale (VAS) and American Orthopaedic Foot & Ankle Society Score (AOFAS). Radiographic assessments included measurement of hallux valgus angle (HVA), intermetatarsal angle (IMA), metatarsal (MT) length and plantar offset of MT head. Results: The mean age was 59.9 years and follow-up were 18.5 months. The average AOFAS increased from 41.2 to 90.9 points and the VAS decreased from 8.1 to 1.3 at the last follow up. Average HVA decreased from 41.2° to 11.6° and IMA reduced from 17.1° to 6.8°. Average shortening of the first metatarsal and the plantar offset of MT head was 3.9 mm and 2.8 mm respectively. There was significant improvement (p

Category: Arthroscopy Introduction/Purpose: The arthroscopic techniques used to treat chronic lateral ankle instability have developed greatly in recent years. The purpose of this work is to present clinical and functional results of patients with chronic ankle instability submitted to surgical treatment by all-inside arthroscopic repair of the anterior talofibular ligament (ATFL). Methods: This is a series of cases of 18 consecutive patients who underwent the all-inside arthroscopic ATFL repair technique, a surgical treatment for chronic lateral ligament instability of the ankle, after the failure of conservative treatment performed for 6 months. The evaluation was made using the American Orthopaedic Foot and Ankle Score (AOFAS), visual analog pain scale (VAS), anterior drawer and talar tilt tests. Surgical complications and patient satisfaction indices were also evaluated. Results: All 18 patients were evaluated for a mean follow-up period of 12 months. There was an improvement in the AOFAS (p< 0.001), with the mean improving from 69.6 points to 98.1, and in the mean VAS score, from 5.0 to 0.5 points (p < 0.001). All ankles were stable, as assessed by the anterior drawer test and talar tilt test. The only complication found was neurapraxia of the superficial fibular nerve in one patient (5%). All of the patients classified the treatment as good or excellent and returned to daily and sports activities without limitations. Conclusion: Treatment of chronic ankle ligament instability by the all inside arthroscopic ATFL repair technique was able to restore ankle stability and showed good clinical results and high satisfaction rates.

Category: Bunion Introduction/Purpose: Minimally Invasive Chevron Akin (MICA) can be used to treat hallux valgus (HV) associated with a hypermobility of the first metatarsal-cuneiform joint (1MTCJ). The aim of this study was to perform a radiographic analysis of the MICA, focused on evaluating the 1MTCJ. Methods: Forty patients (50 feet) with moderate to severe HV underwent a MICA procedure. Radiographic analysis included hallux valgus angle (HVA), intermetatarsal angles between the first and second rays (IMA), the intermetatarsal angle between the proximal fragment of the osteotomy and the second ray (IAPF) and the distance between a point 3 cm distal from the base of the second metatarsal and a point located at the same height for the first metatarsal base (Dist 1-2). The IAPF was compared with the preoperative IMA and the other parameters were compared pre and post-operatively. The radiographic complications were also recorded Results: The majority of patients were female (92%). The mean age was 50.4 years (SD =16.1) and the mean follow-up was 16.1 months (SD = 3.5). The average HVA improved from 32.5 to 7.3 degrees and the average IMA from 14.2 to 4.2 degrees. The IAPF and Dist1-2 values showed an increase of 4.8 and 3.2mm respectively. There were no radiographic complications Conclusion: Minimally Invasive Chevron Akin: Locking the Metatarsal-Cuneiform Joint.

Category: Midfoot/Forefoot; Bunion Introduction/Purpose: Kim et al.'s simulated weight-bearing CT (WBCT) investigation classifying first metatarsal (M1) pronation and its relationship to the metatarso-sesamoid complex suggested a high prevalence (87.3%) of M1 hyper-pronation in hallux valgus (HV). These authors' conclusions have prompted a marked increase in M1 derotation (supination) in HV surgical correction. No subsequent study confirms their M1 pronation values, and two recent WBCT investigations suggest lower normative M1 pronation values. The objectives of our WBCT study were to (1) determine M1 pronation distribution in HV, (2) define the hyperpronation prevalence compared to preexisting normative values, and (3) assess the relationship of M1 pronation to the metatarso-sesamoid complex. We hypothesized identifying a high HV M1 head pronation distribution, but not as high as suggested by Kim et al. Methods: We retrospectively identified 88 consecutive feet with HV in our WBCT dataset and measured M1 pronation with two previously validated methods, the Metatarsal Pronation (MPA) and α angles. Similarly, using two previously published methods defining the pathologic pronation threshold, we assessed our cohort's M1 hyper-pronation prevalence, specifically (1) the upper value of the 95% confidence interval (CI95) and (2) adding 2 standard deviations at the mean normative value (2SD).The position of the sesamoids relative to the crista on the axial plane (sesamoid grading) was assessed according to Talbot et al. classification secondarily adapted by Yildirim et al. on CT scan (Figure).Normality of different variables was assessed using the Shapiro-Wilk test and distribution histogram. Two groups were compared using Student's t-test for normal, and Mann-Whitney U test for non- normal variables. P values less than .05 were considered significant. Results: The mean MPA was 11.4+/-7.4 degrees (IC95%:9.9-13.0; Range: -2.3-37.1) in our HV population and the α angle was 16.2+/-7.4 degrees (IC95%:14.7-17.7; Range: 2.8-43.2). A strong positive correlation was found between these two variables (ρ=0.82;r2=0.79;P

Category: Hindfoot; Midfoot/Forefoot; Other Introduction/Purpose: Peritalar subluxation (PTS) is a crucial feature of Progressive Collapsing Foot Deformity (PCFD). Surrounding structures assume distinct behaviors, contributing to different disease deformities (classes). One of its most traditional aspects is the midfoot abduction (class B), usually noted by a lateral deviation of distal structures at the talonavicular joint. This finding commonly leads surgeons to perform a lateral column lengthening osteotomy for abduction correction, a complex surgery with potential complications. The first ray's ability to reestablish the tripod and restore the hindfoot by derotating structures under the talus was previously theorized. This study aimed to test the capability of the Lapidus and the Cotton procedures in conjunction with a calcaneus displacement osteotomy (MDCO) to improve midfoot abduction in the setting of a collapsed foot. Methods: In this IRB-approved, prospective cohort study, we analyzed patients undergoing medial column instability surgery and evaluated preoperatively with a weight-bearing CT (WBCT). We included individuals receiving a Lapidus bone block procedure or a Cotton for PCFD or Hallux Valgus (HV). Patients having a lateral column lengthening procedure of any type were excluded. Talonavicular coverage angle (TNCA) was measured as a marker of midfoot abduction. Medial arch collapse and forefoot varus were evaluated by the sagittal talus-first metatarsal angle (TFMA), and the forefoot arch angle (FFA) was measured. Associated procedures and the correction amount (displacement or wedge size) were recorded. Normality was estimated by the Shapiro- Wilk test and comparison among timelines by the one-way ANOVA. A multivariate regression analysis was executed to evaluate which of the measurements influenced abduction improvement. Statistical significance was considered for p-values of less than 0.05. Results: A total of 20 patients (age: 43.85 [19-72], BMI 30.98 [SD: 5.95]) were included, 11 PCFD (55%) and 9 HV (45%) with a mean follow-up of 7.5 months (3-12). Bone block Lapidus was performed in most subjects (90%), and the median wedge used was 9mm (5-12mm). MDCO occurred in 55% of patients. All measured variables had improvement with surgery (TNCA: 23.74 to 10.66, p

Category: Basic Sciences/Biologics; Hindfoot; Other Introduction/Purpose: The use of bio-integrative implants in orthopedic surgery is growing rapidly. While many biomechanical and histological studies have been able to demonstrate their structural and biological properties, few clinical reports are available to support their advantages, such as good osteosynthesis, lower rates of removal, and diminished implant-related artifact in imaging studies. This clinical information is vital to providers when choosing the proper material and planning postoperative treatment. Hounsfield Units (HU) algorithms have been used as an objective assessment of joint space width. This pilot data analysis intends to test the capacity of the bio-integrative screws in reaching similar radiographical outcomes of the current metallic screws when analyzing medial displacement calcaneus osteotomies (MDCO). Our hypothesis is that both types of implants would present similar results. Methods: In this prospective comparative IRB-approved study, three patients undergoing MDCO with bio-integrative screws were compared to two patients undergoing the same surgery with metallic screws. Surgeon, primary diagnosis, technique, and displacement were the same for both groups. Patients were assessed using weight-bearing computed tomography at weeks 2, 6, and 12 postoperatively. Using a dedicated software, a 40x40x40mm cube, which defines a volume of interest (VOI), is centered at the osteotomy site. Within the VOI, initial computational analysis focused on image intensity (Hounsfield Units) profiles along lines perpendicular to the osteotomy line, crossing the osteotomy line and spanning approximately 8mm on either side. The HU intensity profiles were recorded, and graphical plots of the HU distributions were generated for each line. The plots were then used to calculate the HU contrast, a proxy for bone healing at the osteotomy site. Results: At 2 weeks, mean HU intensity in the metallic and bio-integrative were respectively 403.25 and 416.28 at the centerline (p=0.312), 513.24 and 386.57 at the inferior (p

Category: Bunion; Hindfoot; Midfoot/Forefoot Introduction/Purpose: The presence of hyperpronation of the first metatarsal (M1) seems to have a clinically significant role in Hallux Valgus (HV). Some authors reported a decrease in recurrence rates after M1 hyperpronation correction in HV. However, when measuring the M1 head pronation relative to the ground, we are assessing and quantifying the aggregate coronal rotational profile of each bone and joint throughout the medial column. Therefore, we do not know the location of this hyperpronation. Moreover, studies showed a strong influence of the hindfoot alignment on coronal rotational measurements and Progressive Collapsing Foot Deformity (PCFD) is a condition frequently associated with HV. Our study aimed to assess and compare coronal plane alignment of medial column bones in HV, PCFD, PCFD HV and controls. Methods: We performed a retrospective IRB approved study. We collected 33 feet who consulted our center with combinations of symptomatic PCFD and HV. We then matched 33 HV, 33 PCFD, and 33 controls for BMI, Gender, and Age to this group. We assessed the coronal plane rotation of the navicular, medial cuneiform, M1 at its base and head, the Sesamoid Rotation Angle (SRA) with respect to the ground, and the hallux valgus angle (HVA) using Weight-Bearing CT images (Figure).The positions of the different joints (first naviculocuneiform (NC1), first tarsometatarsal (TMT1) and metatarsosesamoid rotation angle (MSRA)) were found by subtracting the adjacent angles. Intrinsic torsion of M1 was calculated by subtracting the M1 base angle from the M1 head angle.Normality of different variables was assessed using the Shapiro-Wilk test. Groups were compared using t test or ANOVA for normal and Mann Whitney or Kruskal Wallis for nonnormal variables. Results: HV, PCFD and PCFD HV presented higher M1 intrinsic torsion when compared to controls (respectively 7.3°[CI95%:2.9-11.7], p

Category: Midfoot/Forefoot; Other Introduction/Purpose: Lateral Column Lengthening (LCL), Medial Displacement Calcaneal Osteotomy (MDCO) and Cotton Osteotomy (CO) are considered the work-horse surgical procedures for Progressive Collapsing Foot Deformity (PCFD) correction. The amount of three-dimensional correction induced by each isolated procedure cannot be established in the clinical setting since procedures are frequently performed in combination based on deformity severity and surgeon's preference. Understanding the influence of each one of the procedures, as well as their magnitudes, in the overall 3D correction of the deformity would be extremely helpful in the surgical planning of PCFD. Therefore, our simulated weightbearing cadaveric study aimed to assess the amount of 3D correction induced by different magnitudes of isolated and combined LCL, MDCO, and CO procedures, using weightbearing CT (WBCT) imaging. Methods: In this cadaveric study 12 below-knee specimens with no deformity were used. They were mounted on a frame under 360N of axial load, while keeping conventional stance level tension to tendinous structures. Each group of four specimens underwent isolated and progressive magnitudes of MDCO (6, 10 and 14mm), LCL (6, 8 and 10mm) and CO (4, 8 and 12mm). Following isolated correction, the specimens were randomized into different amounts of combined correction, first with two procedures (only moderate correction; four specimens each combination) and then with three procedures (combined mild, moderate and large corrections; four specimens each). The 3D measurement Foot and Ankle Offset (FAO), representing the relative position between the center of the ankle joint and the weight bearing tripod of the foot, was calculated from WBCT datasets for each specimen in each one of the tested corrected conditions. Comparison between the different conditions was performed using Paired T-Test/Wilcoxon. Results: All isolated performed corrective procedures (MDCO, LCL and CO) significantly influenced FAO measurements (All p- values

Category: Bunion; Lesser Toes; Midfoot/Forefoot Introduction/Purpose: Radiographic measurements are an essential tool to determine the appropriate surgical treatment and outcome for Hallux Valgus (HV). WBCT already demonstrates significant advances that include the ability to perform traditional measurements for HV in the 3D setting reliably, as well as a more complete and accurate evaluation of the deformity. In addition, new software with an advanced semi-automated segmentation system obtains semi-automatic 3D measurements of WBCT scan data sets, minimizing the errors in reading angular measurements. The objective was (1) to assess the reliability of WBCT computer-assisted semi-automatic imaging measurements in HV, (2) to compare semi-automatic with manual measurements in the setting of an HV, and (3) to compare semi-automatic measurements between HV and control group. Methods: In this retrospective IRB (ID# 201904825) approved study, we assessed patients with hallux valgus deformity. The sample size calculation was based on the hallux valgus angle (HVA). Thus, to obtain the 0.8 power, including 26 feet with HV in this study, was necessary. Our control group consisted of 19 feet from 19 patients without HV. Raw multiplanar data was evaluated using software CubeVue. In the axial plane, hallux valgus angle (HVA), intermetatarsal angle (IMA), and interphalangeal angle (IPA) were measured. The semiautomatic 3D measurements were performed using the Bonelogic Software. Inter-rater reliabilities were performed using ICC. Agreement between methods was tested using the Bland-Altman plots. The difference between Pathologic and Control cases using semi-automatic measurements was assessed with the Wilcoxon signed-rank test. Alpha risk was set to 5% (α = 0.05). P

Category: Bunion; Lesser Toes; Midfoot/Forefoot Introduction/Purpose: Hallux valgus deformity (HVD) is a complex 3D distortion that involves varus, dorsiflexion and pronation of the first metatarsal. Deformity is usually assessed by conventional 2D measurements such as hallux valgus and intermetatarsal angle. Weightbearing CT (WBCT) 3D Distance Mapping (DM) and Coverage Mapping (CM) allow assessment of relative positioning between opposing articular surfaces, providing information in regards to articular coverage and joint subluxation, that can potentially influence development of arthritic degeneration and symptoms, as well as dictate outcomes. The aim of this study was to develop a DM and CM algorithm to assess metatarsophalangeal (MTP) and metatarso-sesamoid (MS) joint interaction in HVD patients and compare it to healthy controls. We hypothesized that significant MTP and MS joints lateral subluxation would be observed. Methods: In this IRB-approved study, we included 9 HVD patients (mean age 37.1y; 6F/3M) and 5 controls (mean age 39y; 4F/1M) that underwent foot WBCT foot. Bone segmentation of WBCT images for the first and second metatarsals, first and second proximal phalanxes as well as tibial and fibular sesamoids was performed using specific software. Joint interaction with DM and CM of the first and second MTP joints, as well as MS joints were calculated. The surface of the MTP joints were divided in a 2x2 grid using principal axes to provide a more detailed analysis. DMs were color coded to facilitate data interpretation (Figure). Blue color represented expected normal joint interaction (distances from 1 to 3 mm), yellow/red color symbolized increased joint distances (distances from 3 to 5 mm) and pink color indicate completely uncovered articular areas (distances >5mm). Comparisons were performed with independent t-tests/Wilcoxon. P values

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: Little is known about the intersesamoid crista in Hallux Valgus (HV). However, this structure directly interfaces with the sesamoids and surrounding soft tissues and might play an important role in HV deformity. Our primary objective was to compare the angulation between the crista and first metatarsal (M1) longitudinal axis in HV and controls. Our secondary objective was to assess its correlation with the Distal Metatarsal Articular Angle (DMAA). We hypothesized that the longitudinal axis of the crista will be deviated in valgus in HV and that its position will be correlated with the DMAA. Methods: This IRB approved retrospective case control study evaluated 9 HV and 8 controls matched on age, BMI, and gender. The DMAA was measured as initially described on X-Rays, and then on weight-bearing CT images using a previously validated technique including pronation correction of the M1 called 3d-DMAA. To identify the angle of the inter-sesamoid crista relative to the shaft of the 1st metatarsal, CT scans were semi-automatically segmented to create 3D models of the forefoot. The crista was selected in Geomagic Design X and the resulting STL models were imported into MATLAB for analysis. Principal component analysis was used to identify the direction of both the crista and the 1st metatarsal shaft. The crista-shaft angle is the angle between the directions of greatest variation. Normality was assessed using Shapiro-Wilk tests. Comparisons were made using Student T-tests for normal variables and Mann-Whitney for non-normals. Correlations were assessed using Pearson's coefficients. Results: The crista deviated from the 1st metatarsal shaft in valgus in all the cases (HV and controls). There was a significant increase in valgus deviation of the crista in HV compared to controls (respectively 14.4+/-8.7 degrees and 5.5+/-3.2 degrees; p=0.017). Mean DMAA were respectively 25.1+/-7.9 degrees in HV and 7.4+/-2.9 in controls (p

Category: Sports; Ankle; Ankle Arthritis; Arthroscopy; Trauma Introduction/Purpose: Diagnosing syndesmotic injuries is challenging. Avoiding intra-operative syndesmotic malreduction is even more challenging. Malreduction can be devastating to the long-term health of the ankle joint and has been shown to be more frequent and unforgiving with rigid screw fixation when compared to flexible implants. Syndesmotic position assessment postoperatively is usually performed using bilateral CT. Evaluation is frequently subjective or based on conventional distance, angular, area, and volumetric measurements. Diagnostic accuracy of these measurements is still questionable. The goal of this study was to utilize a 3D Weightbearing CT distance mapping algorithm to objectively assess syndesmotic position in a cadaveric model simulating different patterns of syndesmotic malreduction. We also aimed to evaluate the relative changes in syndesmotic position when fixation was converted from rigid to flexible. Methods: In this cadaveric experimentation, four below-knee specimens were utilized. Specimens were mounted in an external frame simulated weightbearing condition (350N of axial load). Specimens underwent sequential WBCT imaging in four different conditions: native normal ankle, syndesmotic instability, malreduced, and released conditions. In the instability condition, syndesmotic ligaments were surgically released using a conventional limited lateral approach. The malreduced position consisted of controlled 5mm anterior displacement, 5mm posterior displacement, 15o of internal rotation, and over-compressed (160N) states. Fixation was performed with a single implant 20mm proximal to the ankle joint. Implant utilized allowed initial rigid screw- type fixation, followed by implant flexibilization similar to a suture-type fixation (released position). Tibia, fibula, and talus WBCT images were segmented, and syndesmotic incisura and gutter distances were assessed using a 3D distance map algorithm. The syndesmotic position was compared between normal, unstable, malreduced, and released positions. Color-coded representations of the observed differences were presented (Figure). Results: When comparing normal to unstable condition, we observed significant widening of the syndesmotic posterior aspect (average, 13.9%; p=0.004). Overall, all four malreduced positions lead to significantly decreased tibiofibular distances when compared to the unstable state, consistent with syndesmotic over-compression (average, 19.8%; p=0.01), particularly in the posterior aspect of the joint (average, 26.9%; p=0.04). This over-compression was also more pronounced in the anterior displacement (31.5%) and internal rotation malreductions (23.1%). In the released flexible position we found a non-significant trend towards widening of the tibiofibular distances (average, 12%; p=0.08) when compared to the malreduced conditions, indicating partial restoration the syndesmotic relationship. The syndesmotic distances in the released position were also not significantly different from the normal condition. When compared to normal, the lateral gutter demonstrated significant widening in the unstable condition (average 16.7%; p=0.02), narrowing in the malreduced state (average 6.6%; p=0.04), and widening in the released position (average 3.7%; p=0.002). Conclusion: In this study we used 3D WBCT distance mapping to assess syndesmotic position in a cadaveric model simulating syndesmotic instability and multiple syndesmotic malreduction conditions (anterior and posterior displacement, internal rotation and over-compression). We observed significant widening when the syndesmotic ligaments were sectioned, followed by significant tibiofibular narrowing in the malreduced and fixed rigid states. When the implant fixation was released, we observed a trend towards restoration of normal syndesmotic alignment, with relative widening that was however not significantly different from the malreduced rigidly fixed state. Increased sample size cadaveric assessment and clinical studies are necessary to validate our results.

Category: Midfoot/Forefoot; Bunion; Hindfoot Introduction/Purpose: An unstable medial column lever arm may be associated with many conditions, particularly progressive collapsing foot deformity (PCFD), hallux valgus (HV), and midfoot arthritis (MA). Restauration of the first metatarsal length and its lever in the tripod is essential when surgically treating these deformities. Fusion of the first tarsometatarsal joint (TMT) using a structural graft aims to correct the first metatarsal malalignment and create a firm construct on the medial arch. This study aimed to assess early results, healing, and complication rate of a distraction dorsal opening plantarflexion wedge allograft first tarsometatarsal joint fusion in patients with collapse/instability of the medial column. Our main hypothesis is that using a structural allograft on a TMT fusion might present a considerable rate of nonunion. Methods: In this IRB-approved prospective cohort study, patients with a clinical diagnosis of PCFD, HV, MA that underwent a TMT distraction arthrodesis at our institution were evaluated. Adults undergoing the procedure and had performed a weight- bearing computed tomography (WBCT) at 12 weeks postoperatively were included. The technique was carried using a pre-shaped anatomically specific structural allograft and specific implants. Fusion was defined by two fellowship-trained orthopedic foot and ankle surgeons and one fellowship-trained musculoskeletal radiologist, unrelated to the study. A percentage higher than 50% of crossing trabeculae over the entire proximal and distal allograft surfaces had to be noticed. Complications were established as minor (superficial dehiscence, superficial infection, and neuropraxia) and major (deep dehiscence, deep infection, nerve damage, residual deformity, sesamoiditis, limited motion, lateral overload, and reoperation). Collapse correction was assessed by the talus- first metatarsal angle (TFMA). Results: A total of 22 patients (22 feet) were included (11 PCFD, 6 MA, and 5 HV patients) with a mean age of 52.6 years (range, 19-75 years; SD, 14.4), and a mean body mass index (BMI) of 32.9kg/m2 (95% CI, 29.2 to 36.5). Mean follow-up was 5.9 months (range, 3-12), and median allograft size was 8mm (range 5-19mm). Bone healing was observed on 91% of cases, and two patients (one PCFD and one MA) presented a non-union. Two minor complications (9%, both superficial dehiscence) and one major complication (4.5%, deep infection on a MA patient) were observed. Inter-observer reliability for TFMA measurements was excellent, with an ICC of 0.86. Statistically significant improvement of the sagittal plane TFMA was observed, with a mean enhancement of 9.4 degrees (95% CI, 6.7 to 12.1 degrees; p

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: The Minimally Invasive Chevron-Akin (MICA) technique has already demonstrated efficacy compared with other known surgical treatments for mild to moderate Hallux Valgus (HV) deformities. MICA combines percutaneous osteotomies with the benefits of modern rigid internal fixation. By minimizing soft-tissue disruption and allowing large translation of the metatarsal head up to 100%, surgeons have used this technique to address severe deformities as well. The study aim was to evaluate the radiographic parameters, clinical improvement, and potential complications in moderate to severe hallux valgus cases, operated using the MICA technique. Methods: This is a retrospective study conducted between January 2017 and December 2020, that included patients with moderate to severe HV, who underwent surgical correction using the MICA technique. The sample size calculation was based on the AOFAS questionnaire. Thus, to obtain the 0.8 power, including 70 cases in this study, was necessary. The AOFAS score and weight-bearing AP radiographic views for hallux valgus evaluation were applied pre-operatively, after a follow-up period of 6 months, after one year of follow-up, and after two years of follow-up. Visual Analogic Scale (VAS) was applied pre-operatively, after 1 year of follow-up, and after 2 years of follow-up. The following radiographic parameters were measured: metatarsophalangeal hallux valgus angle (HVA), distal metatarsal articular angle (DMAA), and intermetatarsal angle (IMA) between the first and second metatarsals. To compare the measurements over time, Friedman's test was used. p

Category: Midfoot/Forefoot Introduction/Purpose: Weight-Bearing Computed Tomography (WBCT) measurements represent a reliable tool for radiographic analysis of the first ray, including multiplanar assessment in the axial, sagittal, and coronal planes. WBCT can allow for more reliable studies of pathologies, such as Hallux Rigidus (HR), which permits several anatomical points to be evaluated for a correct clinical-radiographic diagnosis. In addition, new software with an advanced semi-automated segmentation system obtains semi-automatic 3D measurements of WBCT scan data sets, minimizing the errors in reading angular measurements. The study`s objective was (1) to assess the reliability of WBCT computer-assisted semi-automatic imaging measurements in HR, (2) to compare semi-automatic to manual measurements in the setting of HR, and (3) to compare semi-automatic measurements between a pathologic (HR) group and a control standard group. Methods: This was a retrospective, IRB approved study of patients with Hallux Rigidus deformity. The sample size calculation was based on the Metatarsus Primus Elevatus (MPE). A control group consisting of 20 feet without HR and a pathologic group consisting of 20 feet with HR was necessary for this study. All WBCT manual and semiautomatic 3D measurements were performed using the following parameters: (1) first Metatarsal-Proximal Phalanx Angle (1stMPP) (sagittal plane), (2) Hallux Valgus Angle (HVA), (3) first to second Intermetatarsal Angle (IMA), (4) Hallux Interphalangeal Angle (IPA), (5) first Metatarsal Lengths (1stML), (6) second Metatarsal Length (2ndML), (7) first Metatarsal Declination Angle (1stMD), (8) second Metatarsal Declination Angles (2ndMD), and (9) MPE. The semiautomatic 3D measurements were performed using the Bonelogic Software. The differences between pathologic and control cases were assessed with a Wilcoxon test and P

Category: Hindfoot; Ankle; Midfoot/Forefoot Introduction/Purpose: Optimization of articular joint coverage has been shown to decrease the progression of arthritic degeneration and to improve outcomes in patients with hip and shoulder pathologies. Progressive Collapsing Foot Deformity (PCFD), previously known as Adult-Acquired Flatfoot Deformity, has been demonstrated to advance with peritalar subluxation (PTS), progressively decreased articular coverage of the subtalar joint articular facets (anterior, middle, and posterior), as well as the development of sinus tarsi and subfibular impingements. Outcome assessment in PCFD has focused on improving conventional radiographic measurements such as the talus-first metatarsal angle and the hindfoot moment arm. This study aimed to evaluate improvements of PTS, subtalar joint articular coverage, and extra-articular impingement following PCFD joint-sparing surgical treatment, as well as the influence of these improvements in patient-reported outcomes. Methods: IRB-approved prospective comparative study. Adult PCFD patients that failed conservative treatment for three-months and underwent hindfoot joint-sparing surgical procedures by a single-surgeon were enrolled. Realignment soft-tissue and bony procedures performed were recorded. All patients underwent Weight Bearing CT (WBCT) preoperatively, and at the 3- and 12- months follow-up. Two observers performed traditional WBCT PCFD measurements. The foot bones were segmented, and distance measurements were performed along the entire 3D superior surface of the calcaneus, including the subtalar joint (SJ) articular facets (anterior, middle, and posterior), sinus tarsi and subfibular area. Color-coded coverage maps (CM) were calculated to grade the amount of articular joint coverage and extra-articular impingement. Patient Reported Outcomes (PROs) were recorded at all follow-up time-points. Pre- and postoperative measurements were compared by paired T-Tests/Wilcoxon and a Multivariate regression analysis was utilized to assess the influence of improvements of articular coverage and impingement in PROs. Results: Twenty patients were included (15F/5M), mean age, BMI, and follow-up of respectively 48.1 (22 to 72) years, 33.88 (23.8 to 46.8) kg/m2, and 13.2 (4 to 27) months. Significant improvements in all traditional PCFD WBCT measurements were noted postoperatively. Articular coverage (CM) of the SJ middle and anterior facets improved postoperatively by respectively 13.5% (p=0.02) and 78% (p=0.001). Similarly, improvement in sinus tarsi impingement, with a 69% decrease in sinus tarsi coverage was observed (p

Category: Hindfoot; Basic Sciences/Biologics; Other Introduction/Purpose: Progressive collapsing foot deformity (PCFD) is a complex three-dimensional (3D) deformity where adjacent structures may adopt subtle differences in positioning that result in increased contact or subluxation. Recent studies have highlighted the need for and utility of 3D analyses in PCFD using weightbearing CT (WBCT) and bone segmentation. Beyond the limitations of triplanar imaging, 3D distance and coverage mapping analyses have further highlighted key regional differences like sinus tarsi narrowing ahead of impingement and early middle facet uncoverage ahead of collapse. However, these analyses rely upon manual identification of subregions hindering the utility of 3D mapping clinically. The objective of this study was to compare an automated selection process with manual selections in the context of subtalar regional distance and coverage maps in PCFD. Methods: In this IRB-approved retrospective study, WBCT data of 20 consecutive patients with flexible PCFD and 10 controls were analyzed. Subregions of the peritalar surface (middle and posterior facets of the calcaneus and talus; sinus tarsi area) were manually selected by two experts on manually generated bone surfaces of all 30 feet. An automated algorithm for selecting coverage area was applied to identify the same regions on the semi-automatically generated bones (Figure). A 3D distance mapping (DM) technique was used to create coverage maps (CMs) across the entire peritalar surface where areas with distances less than 4mm were defined as covered. DM and CM percentages were compared using intra-class correlations and t-tests between PCFD and control groups. The Sørensen–Dice index, or Dice coefficient, was used for comparisons of selections on the semi-automated surfaces to evaluate reproducibility of expert selections. Results: The automated process produced identical selections resulting in perfect intra-method ICCs of 1.00 for all regions and Dice coefficients of 1.00. The average Dice coefficient for all manual selections was 0.903 (range: 0.865-0.935) indicating that observers were able to reliably select the same regions with 90% overlap. When assessing reliability of manual selections, intra- observer ICCs ranged from 0.41-0.92 while inter-observer ICCs ranged from 0.47-0.99 were found. Despite strong significant correlations, average coverage was significantly lower in the sinus tarsi region of the automated selections vs the manual selections (34.3+-16.8% vs 23.1+-12.7%, p

Category: Midfoot/Forefoot; Other Introduction/Purpose: The etiology of hallux rigidus (HR) is not well understood and its association with first-ray hypermobility, hallux valgus and metatarsus primus elevatus (MPE) has not been clearly proven. Recent studies have supported MPE in HR by measuring on weightbearing radiographs (WBR), but there are limitations of WBR due to variation in X-ray projection and superimposed metatarsals. WBCT represent a reliable tool for radiographic analysis of the first ray and can be important for the study pathologies such as HR, which involve several anatomical points to be evaluated for a correct clinical- radiographic diagnosis Our objective was to evaluate radiographic parameters associated with Hallux Rigidus via WBR and WBCT for convergent validity and to evaluate the use of the classification system used in conventional radiography with WBCT. Methods: This is a single-center, retrospective study from prospectively collected data. 20 symptomatic hallux rigidus patient with weightbearing radiograph and WBCT were enrolled from October 2014 to December 2020. Measured parameters included hallux valgus angle (HVA), intermetatarsal angle (IMA), 1st TMT joint version, First and second metatarsal lengths, 2nd cuneiform- 2nd metatarsal angle, Talus-1st Metatarsal angle, First and second metatarsal declination angles, and MPE. MPE was measured as the direct distance between 1st and 2nd metatarsals (modified Horton index). All patients were graded according to the radiographic criteria of Coughlin and Shurnas classification on radiographs and WBCT, separately. Paired T-test was performed to compare radiographic measurements with WBCT. Results: Mean age was 55.9. HVA (15.73° in X-ray vs 14.04° in WBCT), AP first TMT version (16.25° vs 16.47°), 2nd cuneiform- 2nd metatarsal angle (24.54° vs 26.60°), Talus-1st Metatarsal Angle (-7.67° vs -7.89°) were not different between radiograph and WBCT. MPE was measured higher in WBCT by 0.86 mm compared to radiograph. First metatarsal declination angle was lower in WBCT by 2.9° indicating increased MPE. When graded with radiographic findings, 5 (25%) patients were grade 1, 5 (25%) patients were grade 2 and 10 (50%) grade 3, when graded with WBCT, 1 (5%) patient had grade 1, 3 (15%) patients were grade 2 and 16 (80%) grade 3. When graded radiologically, subchondral cyst in proximal phalanx and metatarsal head were better delineated resulting in higher radiographic grade with WBCT. Dorsal subluxation/translation of first metatarsal at first TMT joint was observed 3 (15%) in radiograph and 9 (45%) in WBCT. Conclusion: Hallux Valgus Angle, AP first TMT version, 2nd cuneiform-2nd metatarsal angle, Talus-1st Metatarsal Angel demonstrated consistent measurements in radiograph and WBCT. MPE was measured higher in WBCT when measured with direct distance (0.86 mm) between the first and second metatarsals using modified Horton index and first metatarsal declination angle (2.9°). When graded with WBCT, the subchondral cyst in the proximal phalanx and metatarsal head were better delineated leading to higher grade in WBCT which infer WBCT grading system for HR can aid in early detection of advanced HR with high radiographic grades and potentially guide treatment accordingly.

Category: Hindfoot; Midfoot/Forefoot Introduction/Purpose: Posterior Tibial Tendon (PTT) dysfunction is considered to play an important role in Adult Acquired Flatfoot Deformity recently renamed Progressive Collapsing Foot Deformity (PCFD). Previous flatfoot classifications are mainly based on a progressive mechanical failure of the PTT causing chronological appearance of deformities. A consensus of experts recently met and decided to remove the central place of the PTT dysfunction from the PCFD classification system. The primary objective of our study was to assess the relation between the PTT clinical status and the three-dimensional overall foot deformity. The secondary objective was to assess the relation between the degeneration of PTT at the MRI and the three- dimensional overall foot deformity. We hypothesized that the more damaged the PTT, the more severe the deformity of the foot. Methods: We retrospectively identified all symptomatic PCFD over 18 years old who consulted our center from 01/01/2019 to 12/31/2020. PCFD with concomitant (< 3 mois) clinical examination, Weight-Bearing CT (WBCT) and MRI were included. PCFD presenting with previous surgical intervention were excluded. Finally 25 PCFD were included in the analysis (19 Women, mean age 53.96+/-14.9 years, mean BMI 33.2+/-8.1 kg/m 2 ;)A PCFD presenting either a deficit on the single heel rise test or a decrease in inversion strength (superior or equal to 3/5) was classified PTT deficient. The MRI of all these PCFD were analyzed, and PTT degeneration was classified according to Deland and Rosenberg classifications. The three-dimensional overall deformity of each PCFD was assessed on WBCT by the Foot and Ankle Offset (FAO). Normality of different variables were assessed using Shapiro- Wilk test. Comparisons were performed using Student's t-test or Anova for normal, and Mann-Whitney or Kruskal-Wallis's test for non-normal variables. Results: Patients with clinically deficient PTT (13/25 PCFD, 52%) had a mean FAO of 7.75+/-3.8% whereas patients without PTT deficit (12/25 PCFD, 48%) had a mean FAO of 6.68+/-3.9%, without significant difference between groups (p=0.49). According to Deland classification, 4/25 PTT (16%) were classified grade 0, 7/25 (28%) grade 1, 4/25 (16%) grade 2, 5/25 (20%) grade 3 and 5/25 (20%) grade 4 without any significant difference between groups (p=0.36).According to Rosenberg classification, 4/25 PTT (16%) were classified type 0, 15/25 (60%) type 1, 2/25 (8%) type 2 and 4/25(16%) type 3 without any significant difference between groups (p=0.79).Seven PCFD had a FAO>10%. Among them, 42.9% had a PTT without clinical deficit and 57.1% had a PTT with little or no damage on the MRI. Nine PCFD had a FAO

Category: Ankle Arthritis; Ankle; Trauma Introduction/Purpose: Ankle osteoarthritis (AO) is an incapacitating condition for patients and a substantial burden for medical assistance. It is well known that the vast majority of AO occurs as a sequela of previous trauma. However, it is currently unknown what types of injuries of the foot and ankle most commonly lead to end-stage arthritis. Therefore, the purpose of this study was to investigate the etiology of end-stage ankle osteoarthritis in all patients who underwent ankle fusion or replacement at a tertiary care center over 20 years. We hypothesized that the most common injury patterns would correspond to low-energy lesions. Methods: The electronic medical record was queried using current procedural terminology (CPT) codes for ankle fusion or ankle replacement to identify all patients who underwent either of these procedures at a single tertiary academic center over 20 years. Etiologies were broadly grouped as Pilon/Plafond fracture, ankle fracture, talus fracture, tibia fracture, single or recurrent sprains, infection/septic joint, systemic disorder (Charcot arthropathy, rheumatoid arthritis, hemophilic arthropathy), and idiopathic/primary osteoarthritis. Each fracture pattern was then subclassified using commonly accepted classification systems by two independent observers in addition to the grade of arthritis at the time of fusion or replacement. Reliability among readers was assessed by Kleiss kappa. Normative data were analyzed by ANOVA and comparison among groups and methods by Student's T- test. Results: A total of 533 patients were included in this study. The initial injury patterns were broadly classified as pilon/plafond (65), ankle (173), sprains (110), talus (17), tibia (22), tibiotalar dislocation without fracture (1). Other identified etiologies included rheumatoid arthritis (18), Charcot arthropathy (11), progressive collapsing foot deformity (21), septic arthritis (5), and cavovarus (6). The average time interval between the initial injury and definitive treatment for end-stage arthritis was 558 days. Ankle fractures classified as 44C1 (14,1%), 44B3 (10.6%), 44B2 (9.3%) followed by pilon 43C3 (6.5%) and 43C1 (4.1%) were the most prevalent subclassification found in the fractures group. Conclusion: The primary etiology for AO is secondary due to trauma. A history of ankle sprains and instability was found in 20.6%. Fractures corresponded to 54,6% of our cohort, ankle fractures producing most of these lesions. When considering the subtype of injury, ankle fractures with a 44C1 and a 44B3 classification were the more frequent presentation. These findings could support the argument that complex low-energy rotational traumas do not carry a benign course. Comprehension of the AO etiology scenario may guide prevention policies and specific primary treatment guidelines to diminish disease impact on the population and health care system.

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

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: Hindfoot; Ankle; Ankle Arthritis; Midfoot/Forefoot Introduction/Purpose: Markers used for diagnosis and severity grading are well studied in patients with Progressive Collapsing Foot Deformity (PCFD). Medial facet subluxation (MFS) in weight-bearing computerized tomography (WBCT) has been established as an early indicator of peritalar subluxation (PTS). When the disease affects the ankle leading to a valgus talar tilt (class E), structures distal to this topography may behave differently, trying to compensate for proximal deformity. The aim of this study is to assess predictors of deformity in PCFD patients with and without valgus of the ankle. Our hypothesis is that MFS cannot be used in Class E patients as an accurate marker for the evaluation and staging of PCFD. Methods: In this IRB-approved retrospective case-control study, we analyzed WBCT imaging of 21 consecutive patients with PCFD with valgus of the ankle and 64 controls (flexible PCFD without ankle involvement). MFS (defined by the percentage of uncoverage), middle facet incongruence angle, middle cuneiform-to-floor distance, forefoot arch angle, talonavicular uncoverage angle, hindfoot moment arm (HMA), Foot and Ankle Offset (FAO), and talar tilt angle (TTA) were obtained and compared between groups using one-way ANOVA. A multivariate regression analysis was performed to evaluate which of the measurements influenced the alignment. A partition prediction model was constructed to assess how the variables contributed to the deformity. P values

Study design:Retrospective case-control.Objectives:To characterize changes in American Spinal Injury Association Motor Score (AMS) in patients treated with relative hypertension (HTN) (mean arterial pressure (MAP) > 85 mm Hg for 5 days) with and without preexisting HTN.Setting:A regional spinal cord injury (SCI) center in Pennsylvania, United States.Methods:All patients with an acute SCI who were treated with induced HTN (MAP goal above 85) in the intensive care unit (ICU) for at least 5 days were identified. Patients were stratified based on the presence of preexisting HTN, and the change in the AMS between admission and day 5 was determined. Predictors of outcome were identified using correlation analysis and multiple linear regression.Results:Ninety-two patients met inclusion criteria of which 22 had a previous history of HTN. HTN was a predictor of poor early outcome. Patients with HTN had an average decline in their AMS of 7.6, compared with an average decrease of only 0.6 in the AMS of patients without HTN (P=0.04). HTN had no effect (P>0.05) on other in-hospital variables including length of stay, length of stay in the ICU, complications or mortality. Additionally, multiple linear regression analysis demonstrated that diabetes, coronary artery disease and pulmonary disease had no effect on the change in AMS.Conclusion:Chronic HTN is an independent risk factor for poor early neurologic recovery in patients treated with relative HTN for an acute SCI. This is independent of age and other comorbidities. [ABSTRACT FROM AUTHOR]

STUDY DESIGN.: Retrospective database review. OBJECTIVE.: To determine whether surgical site infections are associated with case order in spinal surgery. SUMMARY OF BACKGROUND DATA.: Postoperative wound infection is the most common complication after spinal surgery, with incidence varying from 0.5% to 20%. The addition of instrumentation, use of preoperative prophylactic antibiotics, length of procedure, and intraoperative blood loss have all been found to influence infection rate. No previous study has attempted to correlate case order with infection risk after surgery. METHODS.: A total of 6666 spine surgery cases occurring between January 2005 and December 2009 were studied. Subjects were classified into 2 categories: fusion and decompression. Case order was determined, with each procedure labeled 1 to 5 depending on the number of previous cases in the room. Variables such as the American Society of Anesthesiologists score, number of operative levels, wound class, age, sex, and length of surgery were also tracked. A step-down binary regression was used to analyze each variable as a potential risk factor for infection. RESULTS.: Decompression cases had a 2.4% incidence of infection. Longer surgical time and higher case order were found to be significant risk factors for lumbar decompressions. Fusion cases had a 3.5% incidence of infection. Posterior approach and revision cases were significant risk factors for infection in cervical cases. For lumbar fusion cases, longer surgical time, higher American Society of Anesthesiologists score, and older age were all significant risk factors for infection. CONCLUSION.: Decompressive procedures performed later in the day carry a higher risk for postoperative infection. No similar trend was shown for fusion procedures. Our results identify potential modifiable risk factors contributing to infection rates in spinal procedures. Specific risk factors, although not defined in this study, might be related to contamination of the operating room, cross-contamination between health care providers during the course of the day, use of flash sterilization, and mid-day shift changes. [ABSTRACT FROM AUTHOR]

STUDY DESIGN.: Retrospective review. OBJECTIVE.: To determine if Anterior/Posterior Combined approach spine surgery is associated with an increased risk of pulmonary embolism (PE) compared to Posterior Only approach surgery. SUMMARY OF BACKGROUND DATA.: Combined anterior/posterior approach spine surgery is associated with a significantly increased risk for PE. However, it is uncertain if there is any difference in risk between combined approaches versus a posterior-only approach. METHODS.: A prospective cohort of patients who underwent anterior/posterior combined approach spine surgery from January 2002 to January 2006 was compared to a retrospective cohort of consecutive patients who underwent posterior only approach spine surgery from September2007 to September 2008. Patient demographics, medical history, body-mass indexes, type of surgery, length of surgery, transfusions, and instrumented vertebral levels were collected from hospital and office records. Hospital records were used to identify patients who developed PE based on diagnosis by spiral CT scan. CT scans were only performed when a patient's clinical picture raised suspicion of PE. Fisher exact test for significance, [chi] test and odds ratios were used for analysis. RESULTS.: A total of 119 patients were included in the study: 63 patients underwent posterior approach spine surgery and 66 patients underwent combined anterior/posterior approach surgery. One patient (1.6%) developed PE after posterior approach surgery while 5 patients (7.5%) developed PE in the combined approach group. Those undergoing combined approaches were 5.08 times more likely to suffer from PE, but this increase was not significant (P = 0.208). Overall, increased risk for PE was associated with the number of levels fused (P = 0.006), total blood loss (P = 0.029), and number of units transfused (P = 0.030). The combined approach was associated with older age (P < 0.001), higher BMI (P = 0.023), more instrumented vertebrae (P < 0.001), greater total blood loss (P < 0.001) and cell saver infusion (P = 0.004) compared to the posterior only approach. CONCLUSION.: Combined anterior/posterior approach spine surgery is associated with an increased risk for pulmonary embolism compared to posterior only approaches. However, regardless of the surgical approach, risk factors for PE common in both groups were operative time, total blood loss, number of levels fused, and the number of units transfused. Patients who undergo spine surgery with prolonged operative times and greater blood loss should be recognized as higher risk patients. [ABSTRACT FROM AUTHOR]