Incongruency Angle Research Articles

Radiographic Outcomes of Titanium Augment vs Bone Graft in Lateral Column Lengthening for Adult-Acquired Flatfoot Deformity.

Lateral column lengthening (LCL) is a surgical procedure used to manage forefoot abduction and, in theory, also increases the longitudinal arch by plantarflexion of the first ray through tensioning the peroneus longus for patients with stage IIB adult acquired flatfoot deformity (AAFD). This procedure utilizes an opening wedge osteotomy of the calcaneus, which is then filled with autograft, allograft, or a porous metal wedge. The primary aim of this study was to compare the radiographic outcomes of these different bone substitutes following LCL for stage IIB AAFD. We conducted a retrospective review of all patients who underwent LCL from October 2008 until October 2018. Preoperative weightbearing radiographs, initial postoperative radiographs, and 1-year weightbearing radiographs were reviewed. The following radiographic measurements were recorded: incongruency angle, talonavicular coverage angle (TNCA), talar-first metatarsal angle (T-1MT), and calcaneal pitch. A total of 44 patients were included in our study. The mean age of the cohort was 54 (range, 18-74). The study cohort was divided into 2 groups. There were 17 (38.7%) patients who received a titanium metal wedge and 27 (61.5%) that received autograft or allograft. Patients that underwent LCL with the autograft/allograft group were significantly older (59 vs 47 years old, P = .006). Patients who underwent LCL with a titanium wedge had a significantly higher preoperative talonavicular angle (32 vs 27 degrees, P = .013). There were no significant differences in postoperative TNCA, incongruency angle, or calcaneal pitch at 6 months or 1 year. At 6 months and 1 year, no radiographic differences were found between autograft/allograft bone substitutes vs titanium wedge in LCL. Level III, retrospective cohort study.

Interobserver Reliability of Radiographic Angles and Measurements in Flat Foot Deformity

Category: Other Introduction/Purpose: Radiographic angles and measurements are widely used in foot and ankle pathologies to define normal and abnormal skeletal alignment. In spite of this the inter-observer reliability of these parameters is debatable. The aim of this study was to determine the inter-observer reliability of various radiographic angles and measurements in flat foot deformity. Methods: Antero-posterior (AP) and lateral foot radiographs of 18 patients with flatfoot deformity were analysed by eight clinicians of various grade of experience (2 consultants, 4 fellows / registrars and 2 core training grades) with 11 different radiological parameters. A digital presentation demonstrating the method of measurement of all parameters using same software was provided to the participants. The inter-observer reliability was analysed using interclass correlation (ICC) model mixed for reliability at 95% confidence interval for individual parameters and different grade of experience. Results: The inter-observer reliability was excellent (>0.9) in calcaneal pitch angle (CPA), medial cuneiform height (C1H) and lateral incongruency angle (LIA). It was good (0.75 - 0.90) in talo-navicular angle (TNA), medial cuneiform articular angle (CAA), medial arch sag angle (MASA), medial cuneiform - 1st MT angle (C1MTA), talonavicular coverage angle (TNCA)andtalar - 1st MT angle on AP radiograph (T1MTA). The inter-observer reliability was moderate (0.5 - 0.75) in Meary's angle and talo-navicular uncoverage percentage (TNUP). The reliability did not differ with the grade of surgeon on sub-group analysis. Conclusion: This is first study to analyse the interobserver reliability of radiographic measurements in a flatfoot deformity, including grade of surgeon. The results suggest that these radiological parameters can be reliably used in clinical practice if standard measurement techniques are followed by clinicians of all grades.

Predictors of Deformity in Patients with Progressive Collapsing Foot Deformity and Valgus of the Ankle

Category:Hindfoot; Ankle; Ankle Arthritis; Midfoot/ForefootIntroduction/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 <0.05 indicated statistical significance.Results:Differences between groups were found for MFS, HMA, FAO, and TTA, with a lower mean value of MFS in PCFD patients with valgus of the ankle. An inverse relation between MFS and TTA was found, which was demonstrated by an increase in the talar tilt and a decrease in middle facet uncoverage. FAO values were affected by MFS in the control group (R2: 0.25) but not in the ankle valgus group (R2: 0.001), which was influenced mainly by the TTA (R2: 0.53). Additionally, a FAO value higher than 12.14 was found to be a strong predictor of deformity at the ankle.Conclusion:Medial facet subluxation was lower in patients with PCFD and valgus of the ankle (Class E), which demonstrates that MFS is a weak predictor of deformity severity. Therefore, this suggests that talar tilt angle and Foot and Ankle Offset should be used as disease markers in this group of patients. Furthermore, a FAO value above 12.14 may be an indicator of ankle involvement in PCFD patients.

Diagnostic accuracy of measurements in progressive collapsing foot deformity using weight bearing computed tomography: A matched case-control study

BackgroundWe aimed to investigate the diagnostic accuracy of known two-dimensional (2D) and three-dimensional (3D) measurements for Progressive Collapsing Foot Deformity (PCFD) in weight-bearing computed tomography (WBCT). We hypothesized that 3D biometrics would have better specificity and sensitivity for PCFD diagnosis than 2D measurements. MethodsThis was a retrospective case-control study, including 28 PCFD feet and 28 controls matched for age, sex and Body Mass Index. Two-dimensional measurements included: axial and sagittal talus-first metatarsal angles (TM1A and TM1S), talonavicular coverage angle (TNCA), forefoot arch angle (FFAA), middle facet incongruence angle (MF°) and uncoverage percentage (MF%). The 3D Foot Ankle Offset (FAO) was obtained using dedicated semi-automatic software. Intra and interobserver reliabilities were assessed. Receiver Operating Characteristic (ROC) curves were calculated to determine diagnostic accuracy (Area Under the Curve (AUC)), sensitivity and specificity. ResultsIn PCFD, mean MF% and MF° were respectively 47.2% ± 15.4 and 13.3° ± 5.3 compared with 13.5% ± 8.7 and 5.6° ± 2.9 in controls (p < 0.001). The FAO was 8.1% ± 3.8 in PCFD and 1.4% ± 1.7 in controls (p < 0.001). AUCs were 0.99 (95%CI, 0.98–1) for MF%, 0.96 (95%CI, 0.9–1) for FAO, 0.90 (95%CI, 0.81–0.98) for MF°. For MF%, a threshold value equal or greater than 28.7% had a sensitivity of 100% and specificity of 92.8%. Conversely, a FAO value equal or greater than 4.6% had a specificity of 100% and a sensitivity of 89.2%. All other 2D measurements were significantly different in PCFD and controls (p < 0.001). ConclusionsMF% and FAO were both accurate measurements for PCFD. MF% demonstrated slightly better specificity. FAO better sensitivity. A combination of threshold values of 28.7% for MF% and 4.6% for FAO yielded 100% sensitivity and specificity.

Prevalence and Pattern of Lateral Impingements in the Progressive Collapsing Foot Deformity

Category:Hindfoot; Midfoot/ForefootIntroduction/Purpose:Lateral impingements, subdivided into Sinus Tarsi (STI), Talo-Fibular (TFI), and Calcaneo-Fibular (CFI) impingements, appear to be associated with the Peritalar Subluxation (PTS) component of the Progressive Collapsing Foot Deformity (PCFD). This is not yet confirmed, as the chronological place of the different types of lateral impingements in PTS is unknown. It is also unclear whether STI are associated with PTS or Midfoot Abduction. Our primary objective was to assess the amount of PTS in STI, TFI and CFI. Our secondary objective was to determine the position of STI among the PTS and Midfoot Abduction deformities. We hypothesized that STI and TFI will be associated with a lower amount of PTS than CFI and that STI will be part involved in both PTS and Midfoot Abduction deformities.Methods:A retrospective study including 72 PCFD assessed with Weight Bearing Computed Tomography (WBCT) was realized. Patients under 15 or with a previous history of surgery were excluded. Lateral impingements were assessed on WBCT images and subdivided as STI, TFI and CFI. Both direct and indirect signs of impingement were considered positive. The amount of PTS was assessed by the percentage of uncoverage and the incongruence angle of the Middle Facet (MF). Midfoot-Abduction was assessed by Talonavicular coverage angle and global foot deformity by Foot and Ankle Offset (FAO). These data were collected by two independent observers and one performed a blinded second assessment. Interobserver and Intraobserver reliabilities were determined using unweighted Cohen's kappa values for lateral impingements and using intraclass correlation coefficients for the measurements. Impingement groups were compared using Student's T-tests for normal, and Mann-Whitney for non-normal variables.Results:Interobserver and Intraobserver reliabilities ranged from substantial to almost perfect for all assessments. STI was present in 84.7%, TFI in 65.2% and CFI in 19.4% of PCFD cases. PCFD with STI showed significant increases of MF uncoverage (p=0.0001), FAO (p=0.0008) and Talonavicular coverage angle (p=0.0197) compared to PCFD without STI. PCFD with TFI did not show significant difference on measurements compared to PCFD without TFI. PCFD with CFI had associated STI in 100% and TFI in 64.2% of cases. PCFD with CFI showed significant decreases of MF incongruence (p=0.0398) and significant higher FAO (p=0.0058) compared to PCFD without CFI. PCFD with both STI and CFI showed significant decreases of MF incongruence (p=0.032) and significant higher FAO (p=0.028) compared to PCFD with isolated STI.Conclusion:Our hypotheses have not been confirmed. STI was associated with both PTS and Midfoot Abduction deformities but neither TFI nor CFI were associated with PTS considering MF subluxation. Conversely, CFI was associated with a reduction of the MF incongruence angle despite being associated with a higher global deformity. STI may be associated with earlier PCFD with a concentration of the malignment forces in the subtalar joint whereas CFI may occur later and be associated with a failure of the deep layer of the deltoid ligament and a talar tilt. This could explain the relative reduction of the PTS in CFI.

Radiographic evaluation of naviculo-cuneiform sag deformity following triplane bunion correction via first tarsometatarsal joint arthrodesis

PurposeTo evaluate naviculo-cuneiform joint sag after first tarsometatarsal joint arthrodesis and the possible correlation between the presence of NC sag, loss of anatomic correction, and other radiographic angle measurements such as Calcaneal inclination and Meary's angle. HypothesisWe propose there is no increase in NC sag following 1st TMTJ arthrodesis and that there is no correlation between NC sag and the calcaneal inclination or Meary's angles. However, we do propose that there is a correlation between post-operative NC sag and loss of triplane bunion correction. Procedures/methodsRetrospective chart review to identify patients with first TMTJ arthrodesis from 2017-first half 2021. Eligible patient's had radiographic analysis and chart reviews performed at 2 weeks, 6 weeks, 12 weeks, and 3-6 months post-operatively. Following that, preoperative and 3-month postoperative weight-bearing radiographs, measuring the following radiographic angles: Meary's angle, Calcaneal inclination angle, Talocalcaneal (Kite's Angle), and NCIA (Naviculo-cuneiform incongruency angle). Loss of correction was measured by either an increase in intermetatarsal angle (IMA) and/or deviation of the sesamoids measured by the tibial sesamoid rotation.Statistical analysis was performed using PRISM version 2. Paired Student's T-test was utilized to compare preoperative and postoperative radiographic angle measurements for NCIA. A Pearson's coefficient correlation was also utilized to assess for any correlation between the preoperative NCIA deformity, post-operative NCIA deformity and the values for pre-operative Calcaneal inclination angle, post-operative Calcaneal inclination angle, pre-operative Meary's angle, and lastly, post-operative Meary's angle. Unpaired Student's t-test was utilized to compare the difference in NCIA post- to preoperative between 96 patients with radiographic union and 15 patients with radiographic non-union. Study designRetrospective chart review and radiographic evaluation.

Predictors of Deformity in Patients with Progressive Collapsing Foot Deformity and Valgus of the Ankle

Category:Ankle; HindfootIntroduction/Purpose:Markers of diagnosis and severity 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 indicator of peritalar subluxation and an earlier detector of the disease. When the disease affects the ankle leading to a valgus talar tilt (class E), structures distal to this topography may behavior differently, trying to compensate 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 could not be used in class E patients as an accurate value for estimation and staging of PCFD.Methods:In this IRB-approved retrospective case-control study we analyzed WBCT acquisitions of 21 consecutive patients with PCFD presenting valgus of the ankle and 64 controls (flexible PCFD with no ankle involvement). MFS (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 Offstet (FAO) and talar tilt angle (TTA) were obtained and compared between groups using oneway ANOVA. A multivariate regression analysis was performed to evaluate which of the measurements influenced the alignment. A partition prediction model was also constructed to find how the variables contributed to the deformity and its aspects. Statistical significancy was set in p values <0.05.Results:We found differences among groups only for MFS, HMA, FAO and TTA, with a lower mean value of MFS in patients with valgus of the ankle. An inverse relation between MFS and TTA was obtained in this group, demonstrated by increase in the talar tilt and decrease in middle facet uncoverage. MFS affected FAO values in the control group (R2: 0.25) but not in the ankle valgus group (R2: 0.001), being that this last one was influenced mainly by the TTA (R2: 0.53). A FAO value higher than 12.14 was found to be a strong predictor of deformity at the ankle.Conclusion:MFS was lower in patients with PCFD and valgus of the ankle, demonstrated as a weak predictor of deformity severity. In this group of patients (class E), talar tilt angle and Foot and Ankle Offset should be used as disease markers. A FAO value above 12.14 must be appreciated as a possible sign of ankle involvement in PCFD patients.

Prevalence and pattern of lateral impingements in the progressive collapsing foot deformity.

The prevalence of lateral bony impingements [i.e., Sinus Tarsi (STI), Talo-Fibular (TFI) and Calcaneo-Fibular (CFI)] and their association with Peritalar Subluxation (PTS) have not been clearly established for progressive collapsing foot deformity (PCFD).This study aims to assess the prevalence of STI, TFI and CFI in PCFD, in addition to their association with PTS. We hypothesized that STI and TFI would be more prevalent than CFI. Seventy-two continuous symptomatic PCFD cases were retrospectively reviewed. Weightbearing computed tomography (WBCT) was used to assess lateral impingements and classified as STI, TFI and CFI. PTS was assessed by the percent of uncovered and the incongruence angle of the middle facet, and the overall foot deformity was determined by the foot and ankle offset (FAO). Data were collected by two fellowship-trained independent observers. Intra-observer and inter-observer reliabilities for impingement assessment ranged from substantial to almost perfect. STI was present in 84.7%, TFI in 65.2% and CFI in 19.4%. PCFD with STI showed increased middle facet uncoverage (p = 0.0001) and FAO (p = 0.0008) compared to PCFD without STI. There were no differences in FAO and middle facet uncoverage in PCFD with TFI and without TFI. PCFD with CFI was associated with STI in 100% of cases. PCFD with CFI showed decreased middle facet incongruence (p = 0.04) and higher FAO (p = 0.006) compared to PCFD without CFI. STI and TFI were more prevalent than CFI in PCFD. However, only STI was associated with PTS. Conversely, CFI was associated with less PTS, suggesting a different pathological mechanism which could be a compensatory subtalar behavior caused by deep layer failure of the deltoid ligament and talar tilt.

Radiographic Outcomes in the Treatment of Type II Adult Acquired Flatfoot Deformity Following Lateral Column Lengthening with a Titanium Wedge versus Autograft or Allograft

Category:Midfoot/ForefootIntroduction/Purpose:Lateral column lengthening (LCL) is a surgical procedure used to manage forefoot abduction occurring in patients with stage IIB Adult Acquired Flat Foot Deformity (AAFD). This procedure utilizes an opening wedge osteotomy of the calcaneus which is then filled with autograft, allograft, or a titanium wedge. The primary aim of this study was to compare the radiographic outcomes of these different bone substitutes in the setting of stage IIB AAFD with the use of LCL.Methods:All patients who underwent LCL from October 2008 until October 2018 were retrospectively reviewed. Preoperative weight bearing radiographs, initial postoperative radiographs and 1-year weight bearing radiographs were reviewed. The following radiographic measurements were recorded: talonavicular uncoverage angle, incongruency angle, and calcaneal pitch.Results:A total of 44 patients were included in our study. The mean age of the cohort was 54 (range 18-74). The study cohort was divided into two groups. There were 17 (38.7%) patients that received a titanium wedge and 27 (61.5%) that received autograft or allograft. Patients that underwent LCL with the autograft/allograft group were significantly older (p=0.006). Patients who underwent LCL with a titanium wedge had a significantly higher preoperative talonavicular angle (p=0.013). There were no significant differences in post-operative talonavicular uncoverage angle, incongruency angle or calcaneal pitch at 6 months or 1 year.Conclusion:Adult acquired flat foot deformity is a difficult disorder to treat surgically. Lateral column lengthening is a common surgical procedure used to treat forefoot abduction that occurs. Our results show that at 6 months and 1 year no radiographic difference exists between autograft/allograft bone substitutes versus titanium wedge in LCL. Future research should evaluate the differences in patient reported outcomes between autograft/allograft versus titanium wedge bone substitutes.

Is Lateral Impingement a Good Predictor of Peritalar Subluxation in Patients with Adult Acquired Flatfoot Deformity?

Category:Ankle Arthritis; Ankle; Hindfoot; OtherIntroduction/Purpose: Sinus tarsi and Subfibular impingement are considered the main causes of lateral foot pain in patients with Adult Acquired Flatfoot Deformity (AAFD). They are considered important markers in the spectrum of progressive peritalar subluxation (PTS) in patients with AAFD. Recent literature has also highlighted the use of the Middle Facet of the subtalar joint as a more accurate indicator of PTS. The objective of this study was to assess the relationship between lateral impingement and middle facet PTS. Our hypotheses were that patients with sinus tarsi and subfibular impingement would demonstrate more severe PTS than patients with no impingement, and that subfibular impingement would represent a better indicator of pronounced deformity when compared to sinus tarsi impingement.Methods: In this retrospective comparative Cohort Study, we included 110 AAFD patients that underwent standing weightbearing CT (WBCT) as a standard baseline assessment of their foot deformity. The presence or absence of sinus tarsi and subfibular impingements, as well as the incongruence angle and percentage of subluxation of the middle facet of the subtalar joint, were manually measured on multiplanar reconstruction (MPR) WBCT images by a blinded fellowship-trained foot and ankle surgeon. Descriptive statistics were used to describe the rate of sinus tarsi and subfibular impingement as well as mean values for middle facet incongruence angle and subluxation. Wilcoxon test was used to compare the values of PTS at the middle facet in patients with or without sins tarsi and subfibular impingement. A partition prediction model was used to assess the values of middle facet PTS that would foresee a higher risk for lateral impingement. P-values <0.05 were considered significant.Results: Seventy-five percent (n=82) of the AAFD patients had sinus tarsi impingement and 64% (n=70) of the AAFD patients had subfibular impingement. The mean value and 95% CI for middle facet incongruence angle and subluxation percentage were respectively 10.5o (CI, 8.7 to 12.2o) and 28.7% (CI, 23.5 to 33.9%). Middle facet subluxation was significantly higher in patients with sinus tarsi and subfibular impingement by respectively 22.6% and 23.9%, both p-values <0.0001. No similar significant differences were observed on incongruence angle measurements. The partition model demonstrated that the middle facet subluxation percentage was the best predictor of both sinus tarsi (R2=0.15) and subfibular impingements (R2=0.17), with 24.9% subluxation representing an important threshold for higher risk of sinus tarsi (90% incidence) and subfibular impingements (84% incidence).Conclusion: Our results showed significantly increased middle facet subluxation in AAFD patients with sinus tarsi and subfibular impingement. Subfibular impingement was less frequent and associated with more pronounced deformity than sinus tarsi impingement. Measurements of the percentage of subluxation of the middle facet were also found to be the best predictor of impingement, with 29.4% representing an important threshold value above which the risks for both sinus tarsi and subfibular impingement were significantly higher. With that in mind, we would recommend close assessment and follow-up of the amount of middle facet subluxation in the decision-making for the treatment of AAFD patients.

Relationship Between Middle Facet Peritalar Subluxation and the Severity of Flatfoot Deformity

Category:Hindfoot; Midfoot/Forefoot; OtherIntroduction/Purpose:Recent literature has established the middle facet of the subtalar joint as a reliable and accurate marker of pronounced peritalar subluxation (PTS) in Adult Acquired Flatfoot Deformity (AAFD) patients. The Foot and Ankle Offset (FAO) has also been accepted as a more complete and three-dimensional (3D) measurement of foot collapse and hindfoot valgus. To date, no assessment has been made regarding the relationship between the severity of the AAFD and the amount PTS measured at the middle facet. The objective of this study was to investigate the correlation between these variables. We hypothesized that direct positive linear correlation would be found, with significantly increased middle facet joint incongruence and subluxation in patients with more pronounced hindfoot valgus and foot collapse.Methods:In this IRB-approved retrospective comparative study, we included 76 feet (42 left, 35 right) with symptomatic AAFD who underwent standing weightbearing CT (WBCT) as standard baseline assessment of their foot deformity. One blinded fellowship-trained foot and ankle surgeon with more than 10 years of experience performed measurements using multiplanar reconstruction (MPR) WBCT images. Manual measurements of subluxation and incongruence of the middle facet were performed at the anteroposterior midpoint of the articular facet. Semiautomatic calculation of the FAO was performed after 3D coordinate harvesting of the weightbearing points of the first, fifth metatarsal and calcaneus as well as the center of the ankle. Correlation of FAO severity and subluxation/incongruence of the middle facet was assessed by Spearman’s correlation and bivariate analysis. Paired Wilcoxon was utilized to compare FAO values in congruent (0% subluxation), subluxated (1-99% subluxation) and dislocated middle facets. P-values <0.05 were considered significant.Results:No significant direct correlation was observed between FAO and Middle Facet Incongruence angle (p=0.12). However, positive linear correlation was found between middle facet subluxation and FAO (Spearman’s 0.54, R2 0.29, p<0.0001). The subluxation of the middle facet was found to increase by 3.5% for every one-point FAO increase (Middle Facet Subluxation (%) = 6.903202 + 3.5452074*Foot and Ankle Offset). Mean values and confidence intervals (CI) of FAO were significantly different depending on the congruency of the middle facet (p=0.0003): congruent, 5.2 (CI, 3.4 to 7.0), subluxated, 8.7 (CI, 6.8 to 9.0) and dislocated, 12.9 (CI, 9.8 to 15.9). Similarly, middle facet subluxation was also found to progressively and significantly increase when FAO values were staged from zero (normal alignment) to four (FAO>20) (p<0.0001).Conclusion:This study is the first to compare and correlate measurements regarding the amount of subluxation of middle facet with the severity of AAFD, when measured by the foot and ankle offset (FAO). We found a significant, positive and linear correlation between the amount of subluxation of the middle facet and FAO measurements. No correlation was found between the incongruence angle of the facet and FAO. Our results support the concept of using the subluxation of the middle facet of the subtalar joint as a key marker of early and progressive deformity in patients with AAFD.

Contribution of First Tarsometatarsal Joint Fusion to Deformity Correction in the Treatment of Adult Acquired Flatfoot Deformity

Category:Midfoot/Forefoot; OtherIntroduction/Purpose:Severe adult-acquired flatfoot deformity (AAFD) is often associated with painful medial column collapse at the naviculocuneiform (NC) joint. The purpose of this study was to examine the role of first tarsometatarsal (1st TMT) fusion combined with subtalar fusion in correcting deformity at this joint.Methods:We retrospectively analyzed 40 patients (41 feet) who underwent 1st TMT and subtalar (ST) fusion as part of a flatfoot reconstructive procedure. We assessed six radiographic parameters both preoperatively and at a minimum of 6 months postoperatively, including talonavicular (TN) coverage angle, lateral talo-first metatarsal angle, lateral talocalcaneal angle, calcaneal pitch, hindfoot moment arm, and a newly defined navicular-cuneiform incongruency angle (NCIA). Patient-Reported Outcomes Measurement Information System (PROMIS) clinical outcomes were assessed preoperatively and at a minimum 1 year follow-up.Results:The NCIA demonstrated excellent interobserver reliability, with no significant change between pre- and postoperative measurements. All other radiographic parameters, except calcaneal pitch, demonstrated statistically significant improvement postoperatively (p <0.01). Overall, patients had statistically significant improvement in all PROMIS domains (p <0.01), except for depression. Worsening NC deformity was not associated with worse patient-reported outcomes.Conclusion:Our data suggests that when addressing collapse of the medial arch in patients with AAFD, fusion of the 1st TMT joint in combination with other procedures leads to acceptable radiographic and clinical outcomes. There was no change in deformity at the NC joint at short-term follow-up, and patients achieved significant improvement in multiple PROMIS domains. Based on our findings, deformity through the NC joint does not significantly impact clinical outcomes. In addition, the NCIA was established as a reliable radiographic parameter that can be used to assess NC deformity in the presence of talonavicular and/or 1st TMT fusion.

Clinical Significance of Measurements in Adult Acquired Flatfoot Deformity using Weight Bearing CT: A Matched Case-Control Study

Category:Hindfoot; OtherIntroduction/Purpose:Adult Acquired Flatfoot Deformity (AAFD) results in progressive foot collapse through peritalar subluxation. Numerous radiographic and Weight Bearing CT (WBCT) measurements have been described in the literature aiming to gauge the severity of the multiple components of the deformity. However, the real diagnostic power of each measurement is currently unknown. Moreover, novel measurements have recently been described such as 3D biometrics and multidimensional measurements. The objective of this case-control study was to individually assess the diagnostic accuracy of known 2D and 3D WBCT measurements and to compare it with a novel multidimensional measurement. We hypothesized that the latter would demonstrate superior diagnostic power than isolated 2D and 3D measurements.Methods:Retrospective case-control study, including 19 AAFD feet and 19 controls that were matched for age, gender and BMI (9 male, 10 female, mean age 54.4 years in both groups). All patients had standing WBCT imaging as baseline assessment of their foot pathology. 2D measurements assessed included: axial and sagittal talus-first metatarsal angles (TM1A), talonavicular coverage angle (TNCA), forefoot arch angle (FFAA) and middle facet incongruence angle (MF°) and uncoverage percentage (MF%). The 3D Foot and Ankle Offset (FAO) was calculated using semi-automatic software. A novel multiplanar biometric measurement (AAFD- MD) was calculated using a multidimensional mathematical algorithm that pooled multiplanar 2D measurements. Intra and interobserver reliabilities were assessed. Comparisons between variables were done using Student-t test or Wilcoxon rank-sum test. Receiver Operating Characteristic (ROC) curves were calculated to determine diagnostic accuracy, sensitivity and specificity of each measurement.Results:AUC for ROC curves were 1. for MF%, 0.96 for FAO, 0.94 for MF° and 0.92 for AAFD-MD. For MF%, a threshold value equal of greater than 28.1% was found to be diagnostic of AAFD with a sensitivity of 100% and specificity of 100%. FFAA were decreased in AAFD: 6.3° versus 15.2° in controls (p<0.001). Axial and sagittal TM1A were respectively 17.6° and 20.8° in AAFD, while in controls: 7.5° (p<0.001) and 6.3° (p< 0.001). The TNCA was increased in AAFD: 27.9° versus 15.6° in controls (p<0.001). In AAFD, MF° and MF% were respectively 13° and 49.4% compared with 5.3° and 10.6% in controls (p<0.001 for both). The FAO was 7.5% in AAFD and 1.1% in controls (p<0.001).Conclusion:The observed results did not confirm our hypothesis. The multidimensional measurement was not as accurate a diagnostic tool as Middle Facet uncoverage percentage which expresses the amount of subluxation of the MF. In that respect, this could mean that congruency of the middle facet could be the last frontier between asymptomatic Pes Planovalgus and symptomatic AAFD, leading to progressive foot collapse, secondarily affecting the FAO. These results also give insight into the meaning of the FAO, which appears here to be a more general assessment of the Foot and Ankle Complex alignment, rather than a marker for a specific pathology.

Contribution of First-Tarsometatarsal Joint Fusion to Deformity Correction in the Treatment of Adult-Acquired Flatfoot Deformity.

Background:Severe adult-acquired flatfoot deformity (AAFD) is often associated with painful medial column collapse at the naviculocuneiform (NC) joint. However, many surgeons surgically correct the deformity without directly addressing this joint. The purpose of this study was to examine the role of first-tarsometatarsal (TMT) fusion combined with subtalar fusion in correcting deformity at the NC joint.Methods:We retrospectively analyzed 40 patients (41 feet) who underwent first-TMT and subtalar (ST) fusion as part of a flatfoot reconstructive procedure. We assessed 6 radiographic parameters both preoperatively and at a minimum of 6 months postoperatively, including talonavicular (TN) coverage angle, lateral talo–first metatarsal angle, lateral talocalcaneal angle, calcaneal pitch, hindfoot moment arm, and a newly defined navicular-cuneiform incongruency angle (NCIA). Patient-Reported Outcomes Measurement Information System (PROMIS) clinical outcomes were assessed preoperatively and at a minimum 1-year follow-up.Results:The NCIA demonstrated excellent interobserver reliability, with no significant change between pre- and postoperative measurements. All other radiographic parameters, except calcaneal pitch, demonstrated statistically significant improvement postoperatively (P < .01). Overall, patients had statistically significant improvement in all PROMIS domains (P < .01), except for depression. Worsening NC deformity was not associated with worse patient-reported outcomes.Conclusions:Our data suggest that when addressing painful collapse of the medial arch in patients with AAFD, fusion of the first-TMT joint in combination with other procedures leads to acceptable radiographic and clinical outcomes. There was no change in deformity at the NC joint in our patient cohort at short-term follow-up, and patients achieved significant improvement in multiple PROMIS domains. Although TMT fusion had no effect on NC deformity, residual or worsening NC deformity did not significantly affect clinical outcomes. In addition, the NCIA was found to be a reliable radiographic parameter to assess NC deformity in the presence of talonavicular and/or first-TMT fusion.Level of Evidence:Level III, retrospective comparative study.

TL 18088 - Subluxation of the middle facet of the subtalar joint as a marker of adult acquired flatfoot deformity peritalar subluxation

Introduction: Progressive peritalar subluxation (PTS) occurs in patients with adult acquired flatfoot deformity (AAFD) and is usually assessed in coronal plane images of the subtalar joint (SJ) posterior facet (PF). In this case control study, we investigated the use of the middle facet (MF) as an indicator of PTS using weightbearing computed tomography (WBCT). We hypothesized that significantly increased joint uncoverage and incongruence would be noted in patients with AAFD. Objective: To assess the amount of subluxation of the middle facet of the subtalar joint as a marker of PTS in patients with symptomatic AAFD when compared to controls using coronal plane WBCT images. Methods: We included 30 patients with stage II AAFD (20 females/10 males), aged 57.4 (range, 24 to 78) years, and 30 matched-pair controls (20 females/10 males), with a mean age of 51.8 (range, 19 to 81) years, who underwent WBCT. Two independent and blinded fellowship-trained foot and ankle surgeons measured the amount of subluxation (percentage of uncoverage) and the incongruence angle of the MF at the midpoint of its longitudinal length, using coronal WB CBCT images. Intra- and interobserver reliability were assessed by the intraclass correlation coefficient (ICC). A comparison was performed using the paired Student’s T-test or for each pair the Wilcoxon test. P-values lower than 0.05 were considered significant. Results: Substantial to almost perfect intra- and interobserver reliability was observed for both measurements. The MF demonstrated significantly increased PTS in patients with AAFD, with a mean value for joint uncoverage of 45.3% (95% CI, 40.5% to 50.1%), as compared to 4.8% (95% CI, 0% to 9.6%) in controls (p&lt;0.0001). Significant differences were also found for the incongruence angle, with a mean value of 17.3 degrees (95% CI, 15.5 to 19.1) in AAFD patients and 0.3 degrees (95% CI, -1.5 to 2.1) in controls (p&lt;0.0001). A joint incongruence angle of more than 8.4 degrees was found to be diagnostic for symptomatic stage II AAFD. Conclusion: We described the use of the subtalar joint middle facet as a marker for PTS in patients with AAFD. Significant differences in the percentage of joint uncoverage and incongruence were found compared with the controls.

Subluxation of the Middle Facet of the Subtalar Joint as a Marker of Peritalar Subluxation in Adult Acquired Flatfoot Deformity: A Case-Control Study.

Progressive peritalar subluxation (PTS) is part of adult acquired flatfoot deformity (AAFD). We investigated the use of the middle facet as an indicator of PTS using standing, weight-bearing computed tomography (CT) images. We hypothesized that weight-bearing CT would be an accurate method of measuring increased subluxation ("uncoverage") and incongruence of the middle-facet among patients with AAFD. We included 30 patients with stage-II AAFD (20 female and 10 male; mean age, 57.4 years [range, 24 to 78 years]) and 30 matched controls (20 female and 10 male; mean age, 51.8 years [range, 19 to 81 years]) who underwent standing, weight-bearing CT. Two independent and blinded fellowship-trained foot and ankle surgeons measured the amount of subluxation (percentage of uncoverage) and the incongruence angle of the middle facet at the midpoint of its longitudinal length, using coronal-plane, weight-bearing, cone-beam CT images. Intraobserver and interobserver reliabilities were assessed using intraclass correlation coefficients (ICCs). Comparisons were performed using independent t tests or Wilcoxon tests. P values of <0.05 were considered significant. Substantial to almost perfect intraobserver and interobserver reliability was observed for both measurements. We found that the middle facet demonstrated significantly increased PTS in patients with AAFD, with a mean value for joint uncoverage of 45.3% (95% confidence interval [CI], 38.5% to 52.1%) compared with 4.8% (95% CI, 3.2% to 6.4%) in controls (p < 0.0001). A significant difference was also found for the incongruence angle, with a mean value of 17.3° (95% CI, 14.7° to 19.9°) in the AAFD group and 0.3° (95% CI, 0.1° to 0.5°) in controls (p < 0.0001). A joint incongruence angle of >8.4° was found to be diagnostic for symptomatic stage-II AAFD. We investigated the use of the middle facet of the subtalar joint as a marker for PTS in patients with AAFD. We confirmed that standing, weight-bearing CT images allowed accurate measurements and that significant differences were found in the percentage of joint uncoverage and the incongruence angle compared with controls. The assessment of the amount of subluxation and incongruence of the middle facet of the subtalar joint represents an accurate diagnostic tool for symptomatic adult acquired flatfoot deformity.

Middle Subtalar Joint Facet Subluxation as a Marker of Collapsing Flatfoot Deformity: A Case-Control Study

Category:HindfootIntroduction/Purpose:Peritalar subluxation comprises part of the three-dimensional and complex distortion that occurs in patients with adult-acquired flatfoot deformity (AAFD) and is characterized by subluxation of the hindfoot through the triple joint complex. It is traditionally graded on weightbearing computed tomography (WBCT) coronal plane images, depending upon the degree of angulation and subluxation of the posterior facet of the subtalar joint. In this case-control study, we describe a new marker of peritalar subluxation represented by the amount of subluxation and joint incongruence of the middle facet of the subtalar joint. We hypothesized that the amount of joint subluxation and incongruence at the middle facet would be significantly increased in patients with AAFD when compared to controls.Methods:Case-control study, we included 30 patients with stage II AAFD (19 females/11 males), mean age 52.2 (range, 29 to 81) years, and 30 controls (18 females/12 males), mean age 49.3 (range, 28 to 83) years, that underwent WBCT as part of the evaluation of their foot condition. Age and gender were statistically similar in both groups. The amount of subluxation of the subtalar joint at the middle facet (% of uncoverage) and angle of joint incongruence, both measured at the midpoint of its longitudinal length, was measured in coronal WB CBCT images by two independent and blinded fellowship-trained foot and ankle surgeons. A second set of measurements was performed after one month (wash-out period). Intra- and interobserver reliability were assessed by Pearson/Spearman’s and Intraclass Correlation Coefficient (ICC), respectively. Comparison was performed using Paired Student T-Test or each pair Wilcoxon rank sum test. P-values lower than 0.05 were considered significant.Results:We found overall good to excellent intra- (range, 0.90-0.95) and interobserver reliability (range, 0.75-0.93) for the measurements. We found significantly increased subluxation of the subtalar joint at the middle facet in patients with AAFD, with a mean value for middle facet uncoverage of 45.3% (95% CI, 40.5% to 50.1%), when compared to 4.8% (95% CI, 0% to 9.6%) in controls (p<0.0001). Significant differences were also found for middle facet subtalar joint incongruence angle, with a mean value of 17.3 degrees (95% CI, 15.5 to 19.1) in AAFD patients and 0.3 degrees (95% CI, -1.5 to 2.1) in controls (p<0.0001).Conclusion:We described the use of the subtalar joint middle facet as a marker for peritalar subluxation in patients with AAFD. We found significant and marked differences in the percentage of joint uncoverage and incongruence when compared to controls. Hopefully, the use of the middle facet as an indicator for peritalar subluxation can potentially help in the early detection of high- risk AAFD patients for progressive collapse and development of sinus tarsi and subfibular impingement, as well as arthritic degeneration of the subtalar joint. Future longitudinal and prospective studies are needed.

Outcomes of the Extended Z-Cut Osteotomy for Correction of Adult Acquired Flatfoot Deformity.

Medial displacement calcaneus tuberosity osteotomy and anterior process lengthening calcaneus osteotomy are traditional single-plane osteotomy techniques used in adult acquired flatfoot deformity reconstruction. More recently, 3-plane step-cut osteotomies were described for each of these and shown to offer improved rotational stability via the horizontal limb. However, a major technical challenge is achieving a sufficiently long horizontal limb to correct deformity through lengthening without losing bony apposition. Combining the anterior process and tuberosity step-cuts using an elongated horizontal limb alleviates this technical challenge, creates a very large surface area for bony healing, and utilizes a single incision. We hypothesized that the Z-cut osteotomy would achieve clinical and radiographic flatfoot deformity correction with a high union rate. This was an institutional review board-approved retrospective study of 16 patients who underwent Z-cut osteotomy for the treatment of moderate to severe symptomatic adult acquired flatfoot deformity, stage IIA/B. The mean radiographic follow-up was 8.8 months, while the mean clinical follow-up was 2.36 years. Radiographic correction was assessed via weightbearing radiographs taken preoperatively and at a mean of 26 ± 2 weeks postoperatively. Measurements included Meary's angle (talo-first metatarsal angle), talonavicular (TN) joint uncoverage percentage, TN incongruency angle, medial cuneiform to fifth metatarsal height, and calcaneal pitch. Union rates and clinical outcomes via the Foot Function Index (FFI) score were assessed preoperatively and at a mean of 29 months following surgery. Paired t test was used to compare both clinical and radiographic outcomes with statistical significance set at P < .05. Fifteen of 16 patients returned an FFI questionnaire with a mean improvement of 52.1 to 10.3 (P = .002). The calcaneal pitch improved from 12.7 to 15.2 degrees (P = .002), the medial cuneiform-fifth metatarsal distance improved from 12.8 to 18.5 mm (P = .002), the TN coverage angle improved from 21.3 to 9.1 degrees (P < .001), the TN uncoverage percentage improved from 32.9% to 20.3% (P < .001), and the TN incongruency angle improved from 41.4 to 19.9 degrees (P < .001). Deformity correction was well maintained in 13 of 16 patients at final follow-up. The union rate of the osteotomy was 100%. Three patients had symptomatic hardware initially; 1 patient required removal of hardware. One patient developed a superficial infection that cleared. Another patient developed peroneal tendonitis, which resolved with corticosteroid injection. The Z-cut osteotomy is a novel, technically simplified, single-incision, single-osteotomy alternative to the previously described double calcaneus osteotomy techniques for reconstructing flexible moderate to severe adult acquired flatfoot deformity that offers comparable short-term clinical and radiographic outcomes with acceptably low complications. Level IV, retrospective case series.

Z-cut Osteotomy for Correction of Adult Acquired Pes Planovalgus Deformity

Category: Ankle Introduction/Purpose: Medial displacement calcaneus tuberosity osteotomy and anterior process lengthening calcaneus osteotomy are traditional single-plane osteotomy techniques used in adult acquired flatfoot deformity reconstruction. More recently, three plane step-cut osteotomies were described for each of these and offer improved rotational stability via the horizontal limb. However, a major technical challenge is achieving a sufficiently long horizontal limb to correct deformity through lengthening without losing bony apposition. Combining the anterior process and tuberosity step-cuts using an elongated horizontal limb (“Z-cut”, Figure 1) alleviates this technical challenge, creates a very large surface area for bony healing, and utilizes a single incision. We hypothesized that the Z-cut osteotomy achieves clinical and radiographic flatfoot deformity correction with a high union rate. Methods: This was an IRB-approved retrospective study of 17 patients who underwent Z-cut osteotomy for treatment of moderate to severe symptomatic adult acquired flatfoot deformity, Stage IIB. Mean follow up was 8.3 months. Radiographic correction was assessed via weight bearing radiographs taken pre-operatively and at a mean of 26 +/- 2 weeks post operatively. Measurements included Meary’s angle (talo-1st metatarsal angle), talonavicular joint (TN) uncoverage percentage, TN incongruency angle, medial cuneiform to fifth metatarsal height, and calcaneal pitch. Union rates, calcaneocuboid joint arthritic changes and clinical outcomes via Foot Function Index (FFI) score were assessed preoperatively and at a mean of 29 months following surgery. Paired t-test was used to compare both clinical and radiographic outcomes with statistical significance set at p&lt;0.05. Results: Nine patients returned an FFI questionnaire with a mean improvement of 52.1 to 10.3 (p = .002). Calcaneal pitch improved from 13.2 to 15.3 (p = .004), medial cuneiform/5th metatarsal distance improved from 13.3 to 18.5 (p = .004), TN coverage angle improved from 22.4 to 9.7 (p &lt; .001), TN uncoverage % improved from 34.3 to 21.2 (p &lt;.001), TN incongruency angle improved from 39 to 20.1 (p &lt; .001). Deformity correction was well maintained in 14 of 17 patients at final follow up. Union rate of the osteotomy was 100%. Three patients had symptomatic hardware initially, one patient required removal of hardware. One patient developed a superficial infection that cleared. Another patient developed peroneal tendonitis, which resolved with corticosteroid injection. Conclusion: The Z-cut osteotomy is a novel, technically simplified, single incision, single osteotomy alternative to previously described double calcaneus osteotomy techniques for reconstructing flexible moderate to severe adult acquired flatfoot deformity which offers comparable short term clinical and radiographic outcomes with acceptably low complications.

Outcomes of a Stepcut Lengthening Calcaneal Osteotomy (SLCO) Compared to Evans Calcaneal Osteotomy for Stage IIb Adult-Acquired Flatfoot Deformity

Category: Hindfoot Introduction/Purpose: Lateral column lengthening is a powerful procedure utilized to correct the associated abduction deformity in stage II flatfoot deformity; however, prior studies have shown complications of nonunion, graft collapse, and lateral column overload with the Evans osteotomy. The Stepcut Lengthening Calcaneal Osteotomy (SLCO) is a z-lengthening calcaneal osteotomy that can correct midfoot abduction while providing inherent stability by creating a large surface area for bony healing. The goal of our study was to compare outcomes in patients undergoing a SLCO versus an Evans osteotomy. It is our hypothesis that patients following a SLCO would have a decreased incidence of nonunion and lateral overload of the foot, and similar improvement in clinical outcome scores. Methods: All consecutive patients from 2006 to 2013 undergoing stage IIB flatfoot reconstruction from our institution’s Foot &amp; Ankle Registry were identified and included. There were 65 Evans &amp; 79 Stepcut patients with a minimum of two year followup. All patients undergoing flatfoot reconstruction were included regardless of associated procedures which were not significantly different between the groups (Table 1). Deformity correction was assessed using preoperative and postoperative weightbearing radiographs. Healing of the osteotomy was assessed by computed tomography (CT). Clinical outcomes were assessed by the Foot and Ankle Outcomes Score (FAOS) survey which has been validated for flatfoot. Rate of return to the OR was also assessed. Differences in continuous variables between groups were assessed with independent samples t-tests, or Mann-Whitney U tests when non-normally distributed. Differences in categorical variables between groups were assessed with chi-squared and Fisher’s exact tests. An alpha level of 0.05 was deemed statistically significant. Results: The Evans group had a 0.9 mm larger graft size (p &lt; 0.001) than the SLCO Group (Table 2). The SLCO group had greater improvement in talonavicular coverage angle (p &lt; 0.001) and talonavicular incongruency angle (p = 0.023) than the Evans group. The Evans group returned more often for additional surgeries (p = 0.030). While there was improvement in mean FAOS scores in both groups for all subscales, only the mean FAOS score for sports activities (p = 0.012) was statistically better in the SLCO group. Rate of nonunion was not statistically significant (p = 0.086) between groups. There was no occurrence of loss of correction or lack of healing of the main (horizontal) arm of the osteotomy site in the SLCO group. Conclusion: Patients who underwent the SLCO for stage IIb adult-acquired flatfoot deformity demonstrated excellent healing, good correction of deformity, utilized a smaller graft size for correction, and less frequently needed to have a second operation on the involved foot. Additionally when compared to the Evans osteotomy, the SLCO group had comparable improvements in FAOS scores; thus making the SLCO a reasonable alternative for lateral column lengthening