Hindfoot Angle Research Articles

Determination of relationship between foot arch, hindfoot, and hallux motion using Oxford foot model: Comparison between walking and running

BackgroundThe foot arch plays an important role in propulsion and shock absorption during walking and running; however, the relationship among the foot arch, metatarsal locking theory, and nature of the windlass mechanism (WM) remain unclear. Research question: What are the differences in the kinematic relationship between the foot arch, hindfoot, and hallux during walking and running? MethodsRelative angles within the foot were measured in 18 healthy men using the Oxford foot model (OFM). Data for barefoot walking at a comfortable speed and rearfoot running at 2.0 m/s were collected. Angles of the forefoot relative to the hindfoot (OFM-arch), hallux relative to the forefoot (Hallux) on the sagittal plane, and hindfoot relative to the shank (Hindfoot) on three anatomical planes were obtained. The medial longitudinal arch (MLA) angle was calculated to verify that OFM-arch can substitute the MLA angle. Each parameter was subjected to cross-correlation analysis and Wilcoxon signed-rank tests to examine the relationship with OFM-arch and compare them during walking and running. ResultOFM-arch was similar to the conventional MLA projection angle in both trials (gait: 0.79, running: 0.96 p < 0.01). Synchronization of the OFM-arch and Hallux angles was higher in running than in walking (gait: −0.09, running: −0.75 p < 0.01). Hindfoot supination was unrelated to OFM-arch. Hindfoot angle on the transverse plane exhibited a moderate relationship with OFM-arch, indicating different correlations in walking and running (gait: 0.63, running: −0.68 p < 0.01).Significance: The elevation of the foot arch due to hallux dorsiflexion differed during walking and running; hence, other factors besides WM (such as intrinsic muscles) may affect the foot arch elevation during running. The hindfoot in the frontal plane does not contribute to arch raising and foot stability during running; it features different relationships with OFM-arch during walking and running.

Correction of ankle varus deformity using patient-specific dome-shaped osteotomy guides designed on weight-bearing CT: a pilot study.

Dome-shaped supramalleolar osteotomies are a well-established treatment option for correcting ankle deformity. However, the procedure remains technically demanding and is limited by a two-dimensional (2D) radiographic planning of a three-dimensional (3D) deformity. Therefore, we implemented a weight-bearing CT (WBCT) to plan a 3D deformity correction using patient-specific guides. A 3D-guided dome-shaped supramalleolar osteotomy was performed to correct ankle varus deformity in a case series of five patients with a mean age of 53.8years (range 47-58). WBCT images were obtained to generate 3D models, which enabled a deformity correction using patient-specific guides. These technical steps are outlined and associated with a retrospective analysis of the clinical outcome using the EFAS score, Foot and Ankle Outcome Score (FAOS) and visual analog pain scale (VAS). Radiographic assessment was performed using the tibial anterior surface angle (TAS), tibiotalar angle (TTS), talar tilt angle (TTA), hindfoot angle (HA), tibial lateral surface angle (TLS) and tibial rotation angle (TRA). The mean follow-up was 40.8months (range 8-65) and all patients showed improvements in the EFAS score, FAOS and VAS (p < 0.05). A 3-month postoperative WBCT confirmed healing of the osteotomy site and radiographic improvement of the TAS, TTS and HA (p < 0.05), but the TTA and TRA did not change significantly (p > 0.05). Dome-shaped supramalleolar osteotomies using 3D-printed guides designed on WBCT are a valuable option in correcting ankle varus deformity and have the potential to mitigate the technical drawbacks of free-hand osteotomies. Level 5 case series.

Effect of Hallux Valgus Correction with Kinesiology Taping on Hindfoot Position. Pilot Study.

Hallux valgus is the most common deformity of the forefoot. It has a multifactorial aetiology, with hindfoot valgus considered one of its causes. The aim of this study was to evaluate hindfoot position and loading pattern after a treatment of Kinesiology Taping (KT) for the mechanical correction of hallux valgus. The study involved 25 feet with hallux valgus deformity and hindfoot valgus. The hallux valgus angle (HVA) and hindfoot angle were assessed with a 3D scanner. Hindfoot loading pattern was examined with a baropodometric platform while standing and during gait. Measurements were taken on the following three occasions: before and immediately after KT placement as well as after a month of taping. The KT treatment had a significant influence on the hindfoot angle (p&lt;0.001) and HVA (p&lt;0.001) measured while standing and on lateral heel loading in dynamic conditions during gait (p&lt;0.01). 1. KT decreased HVA and improved hindfoot position while standing in the pilot study participants. 2. KT exerted a corrective influence on the foot loading pattern in patients with hallux valgus and hindfoot pronation. 3. The foot position correction and normalisation of foot loading achieved in the pilot study provide a basis for further research on KT effectiveness in patients with hallux valgus and hindfoot pronation.

Influence of hindfoot alignment on postoperative lower limb alignment in medial opening wedge high tibial osteotomy.

We have experienced unexpected under-correction after medial opening wedge high tibial osteotomy (MOWHTO). Although the tibia was corrected accurately, the postoperative mechanical axis (MA) was less than 57%. The purpose of this study was to evaluate the relationship between hindfoot alignment and postoperative lower limb alignment, and to reveal whether hindfoot alignment affects lower limb alignment after MOWHTO. Our hypothesis was that hindfoot alignment influences the postoperative MA in MOWHTO. This study was a retrospective comparative study. The study cohort comprised 43 knees in 43 patients who underwent MOWHTO and had standing long-leg anteroposterior view and hindfoot alignment view radiographs taken preoperatively and at 3months postoperatively. To evaluate the hindfoot alignment, the absolute value of the ankle joint line orientation relative to the ground was added to the absolute value of the hindfoot angle. We defined a postoperative MA of 57-67% as acceptable correction (A group) and a MA of < 56% as under-correction (U group). The two groups were analyzed to identify factors that affected postoperative limb alignment. The preoperative hindfoot alignment angle was significantly larger in the U group than the A group. The preoperative hindfoot alignment angle was a significant predictive factor of the postoperative MA, and the cut-off value that distinguished under-correction from acceptable correction was 15.9 degrees. Abnormal hindfoot alignment is one of the causes of under-correction after MOWHTO. Attention should be paid to the preoperative ankle joint line orientation relative to the ground and hindfoot angle. If the preoperative hindfoot alignment angle is ≥ 15.9 degrees, surgeons should reconsider the operative procedure and correction angle. Therapeutic level III, retrospective study.

Reliability testing of the heel marker in three-dimensional gait analysis

IntroductionIn three-dimensional gait analysis, anatomical axes are defined by and therefore sensitive to marker placement. Previous analysis of the Oxford Foot Model (OFM) has suggested that the axes of the hindfoot are most sensitive to marker placement on the posterior aspect of the heel. Since other multi-segment foot models also use a similar marker, it is important to find methods to place this as accurately as possible.The aim of this pilot study was to test two different ‘jigs’ (anatomical alignment devices) against eyeball marker placement to improve reliability of heel marker placement and calculation of hindfoot angles using the OFM. MethodsTwo jigs were designed using three-dimensional printing: a ratio caliper and heel mould. OFM kinematics were collected for ten healthy adults; intra-tester and inter-tester repeatability of hindfoot marker placement were assessed using both an experienced and inexperienced gait analyst for 5 clinically relevant variables. ResultsFor 3 out of 5 variables the intra-tester and inter-tester variability was below 2 degrees for all methods of marker placement. The ratio caliper had the lowest intra-tester variability for the experienced gait analyst in all 5 variables and for the inexperienced gait analyst in 4 out of 5 variables. However for inter-tester variability, the ratio caliper was only lower than the eyeball method in 2 out of the 5 variables. The mould produced the worst results for 3 of the 5 variables, and was particularly prone to variability when assessing average hindfoot rotation, making it the least reliable method overall. ConclusionsThe use of the ratio caliper may improve intra-tester variability, but does not seem superior to the eyeball method of marker placement for inter-tester variability. The use of a heel mould is discouraged.

The incidence of cartilage lesions in anterolateral impingement syndrome of the ankle and their effect on clinical outcome

Aim: To investigate the incidence of concomitant osteochondral lesions of the talus (OLT) and their effect on clinical outcome in anterolateral impingement syndrome (ALIS).Materials and Methods: Patients who underwent ankle arthroscopy due to ALIS of the ankle between 2012 and 2018 were retrospectively screened. The patients were divided into two groups according to the presence of OLT. Preoperatively hindfoot alignment (HA) was measured on long axial view radiographs. All measurements were performed by the experienced musculoskeletal radiologist. The association between osteochondral lesions of the talus and hindfoot alignment disorder was statistically assessed. The patients before and after surgery were evaluated with American Orthopedic Foot and Ankle Society (AOFAS) Hindfoot score for clinical performance.Results: OLT accompanied impingement syndrome in 38 (34.8%) of 109 patients examined. The preoperative and postoperative AOFAS Pain and AOFAS Function results were found no significantly different between the two groups according to the presence of OLT (n.s.). However, AOFAS Alignment results of OLT (-) Group were significantly higher than OLT (+) Group. Mean Hindfoot Angle (HA) was −3.7 ± 12.8 (varus) and 4.6 ± 11.2 (valgus) in feet with and without OLT, respectively (Table 1). In this study, there was a significant association between positive OLT and clinical varus hindfoot (p .001)Conclusion: In the current study the hindfoot alignment showed association with the location of OLT in Anterolateral Impingement Syndrome. However, it was also determined that the presence of chondral damage had no negative effect on the treatment of anterolateral impingement syndrome. It should be kept in mind that this syndrome can be accompanied by osteochondral lesions of the talus at a significant rate.

Effect of Unilateral Accessory Navicular Bone on Radiologic Parameters of Foot

This study aimed to compare the radiologic parameters of both feet in patients with unilateral accessory navicular bone (ANB) and evaluate the differences from one another. Forty-one patients with unilateral ANB volunteered to participate in this study from August 2019 to January 2020. Patient data, including age, sex, body mass index (BMI), type of ANB, and presence of symptoms were obtained. Group 1 comprised 23 patients with asymptomatic unilateral ANB, and group 2 comprised 18 patients with symptomatic unilateral ANB. Seven radiologic parameters were evaluated assessing hindfoot, midfoot, and forefoot alignment-calcaneal pitch angle, talocalcaneal angle, tibiocalcaneal angle, naviculocuboid overlap (NCO), talonavicular coverage angle (TNCA), anteroposterior talo-first metatarsal angle, and lateral talo-first metatarsal angle. The mean age of patients was 40.1 years in group 1 and 42.6 years in group 2. Mean BMI was 25.2 in group 1 and 26.6 in group 2. No significant differences were noted in the radiologic parameters between the ANB and contralateral sides in all patients. The radiologic parameters of both feet in symptomatic and asymptomatic patients were not significantly different. No significant differences were noted between the affected sides of type 1 and 2 ANB and contralateral sides in terms of the radiologic parameters. BMI was significantly correlated with NCO and TNCA. This study demonstrated that the presence of an accessory navicular bone did not affect radiologic parameters of the foot. Radiologic parameters of both feet in symptomatic patients were not significantly different. Level III, diagnostic, comparative study.

Comparison of Change in Hindfoot Alignment with Coleman Block Testing Using Clinical Exam, X-ray, and Weight-bearing CT

Category:Hindfoot; Midfoot/ForefootIntroduction/Purpose:The Coleman block test has traditionally been used to distinguish between forefoot- and hindfoot-driven deformity as well as flexibility of cavovarus deformity. However, there has been no validation of the Coleman block test using x- rays or weightbearing CT scan. The purpose of this study was to compare hindfoot alignment in cavovarus feet with and without the Coleman block using clinical exam, x-ray, and weightbearing CT scan.Methods:We retrospectively evaluated 7 feet in 7 patients. The average age was 57, there were 5 males, and the average BMI was 34.7. Average calcaneal pitch was 30 degrees. Clinical measurements were made using standing talocalcaneal angle (STCA) and resting calcaneal stance position (RCSP) with and without a Coleman block using a camera positioned at 0 degrees to the heels.Hindfoot angle (HFA) was measured off of Saltzman-view x-rays and off of weightbearing CT coronal reconstructions with and without the Coleman block. Finally, foot ankle offset (FAO) was measured with and without the Coleman block from weightbearing CT using Cubeview TALAS software. Differences before and after Coleman block were measured using paired t- testing and correlations between different hindfoot alignment measurements were made using Pearson correlation coefficients.Results::The average change in STCA before and after Coleman block placement was 2.9 degrees (7.14 varus without block, 4.28 degrees of varus with block; p<0.05). The average change in hindfoot angle before and after Coleman block using X-ray was 7.4 degrees (14 degrees varus without block, 6 degrees varus with block; p=0.08), and using CT was 3.9 degrees (14 degrees varus without block, 10 degrees varus with block; p= 0.06). There was no significant change in FAO before and after Coleman block testing. STCA was best-correlated with FAO (R= 0.7, p<0.05). CT HFA was also well-correlated with FAO (R=0.68, p<0.05).There was lesser correlation between X-ray HFA and FAO (R=0.608, p<0.05) and X-ray HFA and SCTA (p=0.63, p<0.05).Conclusion::Although Coleman block testing resulted in a decrease in varus, no patient had full re-constitution of physiologic hindfoot valgus with any measurement method. This suggests that either the forefoot was a partial (but never a complete) ‘driver’ of hindfoot varus deformity, or that there was some degree of rigidity in all patients tested. FAO did not demonstrate a statistically significant difference with and without Coleman block on this small sample size. FAO was best correlated with both clinical exam and CT HFA measurements. Clinical exam and weightbearing CT may be more reliable than radiographs in measuring cavovarus hindfoot alignment.Figure 1.

Redefining Hindfoot Alignment Based on Pathology rather than Morphology: A Prospective Observational Diagnostic Study on 250 Feet

Category:Ankle; Ankle Arthritis; Bunion; Hindfoot; Midfoot/Forefoot; OtherIntroduction/Purpose:The analysis of the hindfoot alignment (HA) is important in the management of various foot and ankle pathologies. Foot Ankle Offset (FAO), measured using Weight Bearing CT (WBCT) scans is a 3D biometric measurement of HA described in the literature, however only with relation to the clinical morphology of the hindfoot or previously known 2D biometrics such as the hindfoot angle. The aim of this study was to observe the FAO distribution on a continuous, large population of patients and to analyze its discriminating power between pathological and non-pathological cases. We hypothesized that threshold values could be determined for the normal range of FAO in terms of risk of presenting with different pathologies in varus or valgus configurations.Methods:Prospective, IRB approved (COS-RGDS-2016-06-008-P-LINTZ-F, Clinical Trials NCT 04134962), level II study. 125 patients (250 feet) with bilateral WBCT as standard follow-up were included at a single institution. Mean age was 54 years (18-84), 58.4 % were female. Each patient was clinically evaluated, scans analyzed by a fellowship-trained foot and ankle surgeon and all degenerative pathologies classified depending on their anatomical location (medial or lateral). HA was measured using FAO on 3D datasets and Tibio-Calcaneal Angle (TCA) on 2D Saltzman-El-Khoury views. All scans were analyzed a second time by a radiology MD. FAO and TCA Intraclass Correlation Coefficient (ICCs) and Spearman’s correlation coefficient were calculated. Mean FAO values were calculated for all, normal, varus and valgus cases, and each pathology group. Receiver operating Curves (ROC), threshold values of FAO and area under the curve (AUC) were established for predicting an increased risk of medial or lateral pathologies.Results:A threshold FAO value of -1.64% was found to best predict the risk of lateral pathology (51.4% sensitivity, 85.1% specificity, AUC=0.72) and 2.71% (95% sensitivity, 82.8% specificity, AUC=0.93) for medial pathology, both versus no pathology. Mean FAO value was 1.65% +-4.72% and mean TCA was 4.15° +-7.67°. Interobserver reproducibility for FAO and TCA was respectively 0.96 [95% CI 0.95-0.97] and 0.95 [95% CI 0.94-0.96]. Spearman’s correlation coefficient between FAO and TCA was 0.697. Clinical assessment rated 167 feet as normal, 33 varus, and 50 valgus. Mean FAO values were respectively 0.99 +-3.26%, - 2.53+-5.05 % and 6.81+-2.70%. We found that the mean FAO was 0.42+-3.19 % for non-pathologic feet, -2.30+-4.58 for lateral pathologies, 6.62+-2.77 for medial pathologies.Conclusion:The most important finding in this prospective clinical trial is the description of normal HA as the FAO range in which the risk for degenerative Foot and Ankle pathology is the least: -1.64% to 2.71%. This new, pathology based prognostic approach to HA is different to the traditional morphological approach. The potential of WBCT to provide computerized, data- based and biomechanically meaningful 3D measurement tools could improve the prognostic potential of biometrics such as HA. Results will be refined in the future by increasing the size of study population.

3D imaging for hindfoot alignment assessment: a comparative study between non-weight-bearing MRI and weight-bearing CT.

The authors compared measurements of hindfoot alignment on MR imaging with weight-bearing CT (WB-CT) to establish the degree of correlation. Forty-seven feet in 44 patients had weight-bearing CT and MRI studies performed on the same day. Hindfoot alignment on MRI was assessed by two radiologists who calculated tibiocalcaneal angle (TCA) and calcaneofibular ligament angle (CFLA). On WB-CT, foot ankle offset (FAO), calcaneal offset (CO) and hindfoot angle (HA) were assessed by a senior Foot and Ankle Surgeon using dedicated software. Pearson correlation coefficient was used to evaluate the correlation between these measurements. The study group comprised 27 males and 17 females with a mean age of 45years (range 13-79years). A statistically significant positive correlation was identified between TCA on MRI and all measurements of hindfoot alignment on WB-CT (p = 0.001-0.005). The CFLA on MRI only had significant correlation with CO on WB-CT (p = 0.03). A significant negative correlation was observed between both MRI parameters (p < 0.001). A highly significant correlation between tibiocalcaneal angle on non-weight-bearing ankle MR imaging and hindfoot alignment measurements on weight-bearing CT was identified.

The Effect of Total Knee Arthroplasty on Hindfoot Alignment in Patients with Severe Genu Varum and Genu Valgum.

The maintenance of deformity in the ankle and hindfoot after correction of knee deformity following knee arthroplasty may cause abnormal tension in the knee and patient dissatisfaction. The aim of this study was to determine the effect of knee arthroplasty on the hindfoot alignment in patients with severe genu varum and valgum. A total of 84 patients with primary osteoarthritis, were enrolled in the study. The knee deformity was measured using a long leg film before surgery. The long axial radiographic view of hindfoot was taken in the standing position for all patients, before and six months after surgery. Comparisons were made on changes in the hindfoot angles measured before and after surgery. A total of 84 patients with mean age of 62.28 ± 7.77 years, 77 (92%) and seven patients (eight percent) had knee varus and valgus deformity, respectively. In the knee varus group, the mean preoperative hindfoot angle was + 5.32 ± 6.12 ° (valgus) which was changed to - 0.25 ± 4.91 ° (varus) in the postoperative phase. In the knee valgus group, the mean pre and postoperative hindfoot angles were - 7.71 ± 7.06° (varus) and - 2.14 ± 5.92 ° (varus), respectively. The mean preoperative hindfoot angle in severe and very severe varus knee groups were + 5.45 ± 3.30 and + 5.28 ± 6.86 °, respectively. These angles were changed to + 0.21± 5.17 and -1.60 ± 3.89° six months after surgery, respectively. The mean preoperative hindfoot angle in severe and very severe valgus knee deformity groups were - 7.00 ± 4.69 and -8.66 ± 10.69 °, respectively. These angles were changed to - 2.00 ± 5.71 and - 2.33 ± 7.50 °after surgery, respectively. There was no significant difference between patients with severe and very severe deformity in terms of pre and post-operative hindfoot angle. The hindfoot alignment is significantly corrected after knee arthroplasty. The severity of knee deformity does not correlate with the severity of the hindfoot deformity before and after surgery.

Is Lower-limb Alignment Associated with Hindfoot Deformity in the Coronal Plane? A Weightbearing CT Analysis.

The goals of lower limb reconstruction are to restore alignment, to improve function, and to reduce pain. However, it remains unclear whether alignment of the lower limb and hindfoot are associated because an accurate assessment of hindfoot deformities has been limited by superposition on plain radiography. Consequently, surgeons often overlook hindfoot deformity when planning orthopaedic procedures of the lower limb. Therefore, we used weight-bearing CT to quantify hindfoot deformity related to lower limb alignment in the coronal plane. (1) Is lower-limb alignment different in varus than in valgus hindfoot deformities for patients with and without tibiotalar joint osteoarthritis? (2) Does a hindfoot deformity correlate with lower-limb alignment in patients with and without tibiotalar joint osteoarthritis? (3) Is joint line orientation different in varus than in valgus hindfoot deformities for patients with tibiotalar joint osteoarthritis? (4) Does a hindfoot deformity correlate with joint line orientation in patients with tibiotalar joint osteoarthritis? Between January 2015 and December 2017, one foot and ankle surgeon obtained weightbearing CT scans as second-line imaging for 184 patients with ankle and hindfoot disorders. In 69% (127 of 184 patients) of this cohort, a combined weightbearing CT and full-leg radiograph was performed when symptomatic hindfoot deformities were present. Of those, 85% (109 of 127 patients) with a median (range) age of 53 years (23 to 75) were confirmed eligible based on the inclusion and exclusion criteria of this retrospective comparative study. The Takakura classification was used to divide the cohort into patients with (n = 74) and without (n = 35) osteoarthritis of the tibiotalar joint. Lower-limb measurements, obtained from the full-leg radiographs, consisted of the mechanical tibiofemoral angle, mechanical tibia angle, and proximal tibial joint line angle. Weightbearing CT images were used to determine the hindfoot's alignment (mechanical hindfoot angle), the tibiotalar joint alignment (distal tibial joint line angle and talar tilt angle) and the subtalar joint alignment (subtalar vertical angle). These values were statistically assessed with an ANOVA and a pairwise comparison was subsequently performed with Tukey's adjustment. A linear regression analysis was performed using the Pearson correlation coefficient (r). A reliability analysis was performed using the intraclass correlation coefficient. Lower limb alignment differed among patients with hindfoot deformity and among patients with or without tibiotalar joint osteoarthritis. In patients with tibiotalar joint osteoarthritis, we found knee valgus in presence of hindfoot varus deformity and knee varus in presence of hindfoot valgus deformity (mechanical tibiofemoral angle 0.3 ± 2.6° versus -1.8 ± 2.1°; p < 0.001; mechanical tibia angle -1.4 ± 2.2° versus -4.3 ± 1.9°; p < 0.001). Patients without tibiotalar joint osteoarthritis demonstrated knee varus in the presence of hindfoot varus deformity compared with knee valgus in presence of hindfoot valgus deformity (mechanical tibiofemoral angle -2.2 ± 2.2° versus 0.9 ± 2.4°; p < 0.001; mechanical tibia angle -1.8 ± 2.1° versus -4.3 ± 1.9°; p < 0.001). Patients with more valgus deformity in the hindfoot tended to have more tibiofemoral varus (r = -0.38) and tibial varus (r = -0.53), when tibiotalar joint osteoarthritis was present (p < 0.001). Conversely, patients with more valgus deformity in the hindfoot tended to have more tibiofemoral valgus (r = 0.4) and tibial valgus (r = 0.46), when tibiotalar joint osteoarthritis was absent (p < 0.001). The proximal joint line of the tibia had greater varus orientation in patients with a hindfoot valgus deformity compared with greater valgus orientation in patients with a hindfoot varus deformity (proximal tibial joint line angle 88.5 ± 2.0° versus 90.6 ± 2.2°; p < 0.05). Patients with more valgus deformity in the hindfoot tended to have more varus angulation of the proximal tibial joint line angle (r = 0.31; p < 0.05). In patients with osteoarthritis of the tibiotalar joint, varus angulation of the knee was associated with hindfoot valgus deformity and valgus angulation of the knee was associated with hindfoot varus deformity. Patients without tibiotalar joint osteoarthritis exhibited the same deviation at the level of the knee and hindfoot. These distinct radiographic findings were most pronounced in the alignment of the tibia relative to the hindfoot deformity. This suggests a detailed examination of hindfoot alignment before knee deformity correction at the level of the proximal tibia, to avoid postoperative increase of pre-existing hindfoot deformity. Other differences detected between the radiographic parameters were less pronounced and varied within the subgroups. Future research could identify prospectively which of these parameters contain clinical relevance by progressing osteoarthritis or deformity and how they can be altered by corrective treatment. Level III, prognostic study.

PO 18239 - Malerba Z-type osteotomy for the treatment of adult acquired flatfoot deformity

Introduction: Adult acquired flat foot deformity (AAFD) is a condition characterized by tendon and ligament failure that leads to progressive midfoot collapse and to hindfoot valgus. Calcaneal osteotomies are among the oldest and most conventional procedures for the treatment of angular limb deformities; they aim to reestablish the alignment and the line of action vector of the triceps surae muscle. Various disadvantages of classic osteotomies have been established in recent years, such as fixation loss, insufficient correction and reduced tarsal tunnel volume. Malerba Z-type osteotomy aims to resolve possible complications resulting from the usual incisions, to enhance the procedure and to allow multiplane corrections. Objective: To describe the functional and radiographic outcomes of Malerba Z-type osteotomy in patients with AAFD subjected to reconstructive surgery. Methods: Ten patients diagnosed with AAFD, with a mean age of 45 years (35-55), were operated on from January 2017 to January 2018. All patients underwent weight-bearing radiographs and alignment measurements and functional assessment using the pain visual analog scale (VAS) and the American Orthopedic Foot and Ankle Society (AOFAS) scale preoperatively and at the final evaluation at a mean of 12 months (6-18 months) after surgery. Results: The 10 patients showed positive progression after the surgery, reporting no major complications. Only one case of superficial dehiscence and one case of transient sural nerve neuropraxia (in different patients) were observed. On average, the AOFAS score increased by 50 points on average (25.7 to 76.6), and the VAS score decreased by 4 points (8.3 to 3.4). The mean calcaneal pitch increased from 5.5° to 15.2°. Nine patients transitioned from valgus malalignment (hindfoot angle greater than 10°) to the physiological (5 to 10° valgus) range. Conclusion: Ankle-foot realignment is an essential condition for surgical success in AAFD; it promotes a soft-tissue healing environment while maintaining an adequate muscle line of action. Malerba Z-type osteotomy was found to be a safe technique with high potential for deformity correction, leading to functional and radiographic improvement in patients who undergo this surgery.

Pes Cavovarus in Charcot-Marie-Tooth Compared to the Idiopathic Cavovarus Foot: A Preliminary Weightbearing CT Analysis

Category:Ankle, HindfootIntroduction/Purpose:Charcot-Marie-Tooth disease (CMT) is an inherited sensory motor peripheral neuropathy progressively leading to cavovarus deformity of the foot. Conversely, the idiopathic cavovarus foot represents a non-neurological condition, with a spectrum from subtle to markedly deformed. Our aim was to investigate morphological differences between CMT pes cavovarus (CMT-PC), idiopathic pes cavovarus (I-PC) and normally aligned feet using three-dimensional (3D) cone beam weightbearing computed tomography (WBCT) measurements. We hypothesised that the hindfoot alignment was significantly different between the three groups.Methods:Retrospectively, we compared 17 CMT-PC (15 patients) with 24 I-PC and 24 clinically normally aligned feet. Patients were comparable by age, sex and body mass index. All WBCTs were performed during routine investigation. Exclusion criteria included previous ipsilateral foot/ankle surgery and inability to heel weightbear. Three measurements were made by one orthopaedic surgeon: foot and ankle offset (FAO), a three-dimensional calculation describing the relationship between the centre of gravity of the tripod of the foot and the centre of the ankle; calcaneal offset (CO), measuring the distance between a theoretically neutral position of the calcaneus and its true position; and hindfoot angle (HA), an estimative of coronal angular hindfoot alignment. These measurements were all repeated twice for intraobsever reliability calculation (Pearson correlation). The mean values were compared using one-way ANOVA (values normally distributed after Shapiro-Wilk test) with the Bonferroni test.Results:Intraobserver reliability was excellent for all the three measurements (r=0.98 for FAO, CO and HA). Mean FAO value ± standard deviation in CMT-PC group (-14.1% ± 7.2) and in I-PC group (-9.6% ± 5.2) both differed from normal feet (1.6% ± 3.3) (p< .001). Of note, a difference was found between mean FAO in CMT-PC and I-PC feet (p .025). Furthermore, the mean CO (- 23.6 mm ± 11.3 in CMT-PC, -16.7 mm ± 8.2 in I-PC and 3.1 mm ± 6 in normal feet) and the mean HA (-44.9° ± 21.7 in CMT-PC; - 30.3° ± 16.9 in I-PC; 5.1° ± 10.1 in normal feet) significantly differed in three groups (p< .001) and specifically between CMT-PC and I-PC feet (p .032 and p .02 for CO and HA, respectively).Conclusion:This study confirms our hypothesis. Hindfoot alignment in patients diagnosed with CMT cavovarus and idiopathic cavovarus feet significantly differed between them and from normal controls, with a more accentuated varus deformity in CMT patients. This probably reflects the presence of a known neuromuscular imbalance driving the deformity over time in CMT feet. We therefore propose using a reliable method of quantifying heel varus and seeking a potential neurological diagnosis in the more severe.

Intraobserver and Interobserver Reliability of Cone Beam Weightbearing Semiautomatic Three- Dimensional Measurements in Symptomatic Pes Cavovarus

Category:Basic Sciences/Biologics, HindfootIntroduction/Purpose:Pes cavovarus is a three-dimensional complex foot deformity variably involving a varus hindfoot, high longitudinal arch and forefoot adduction. Two-dimensional radiographs may be flawed by rotational bias and operator-related bias, while standard computed tomography (CT) cannot be perfomed in loading conditions. Three-dimensional (3D) cone beam weightbearing computed tomography (WBCT) may overcome these drawbacks, obtaining physiological weightbearing images with low-dose radiation. New 3D semiautomatic tools have been proposed to measure hindfoot alignment, but reliability in pes cavovarus has never been tested. The aim of this study was to assess intra and interobserver reliability of 3D biometrics on WBCT imaging in pes cavovarus. Our hypothesis was that foot and ankle offset, calcaneal offset and hindfoot angle were reliable measures regardless of type and severity of deformity.Methods:Cone beam WBCT anonymised datasets from 34 pes cavovarus (PC) (17 neurological, 17 non-neurological) and 17 normal feet were retrospectively reviewed. All WBCTs were performed during routine investigation. Inclusion criteria consisted of no previous ipsilateral foot/ankle surgery and ability to heel weightbear. Three foot and ankle surgeons (blinded to patient diagnosis) independently measured the following variables on 51 feet: foot and ankle offset (FAO), calcaneal offset (CO) and hindfoot angle (HA) using dedicated software. Each observer repeated all measurements two-weeks apart. The Shapiro–Wilk test was used to assess normality of data distribution. The Pearson or Spearman correlation test and Intraclass Correlation Coefficients (ICCs) and were used to assess intra and interobserver reliability, respectively. Subgroup analysis was performed to assess whether clinical diagnosis (neurological PC, non-neurological PC, normal controls) or severity of varus deformity (4 groups based on FAOs 25th, 50th and 75th centiles) could affect reliability of FAO measurements.Results:Intra and interobserver reliability for FAO (r= 0.98; ICC: 0.98), CO (r=0.94; ICC 0.89) and HA measurements (r=0.93; ICC:0.89) were excellent. Subgroup analysis showed that FAOs intra and interobserver reliability remained excellent in neurological PC (r= 0.96; ICC: 0.97), non-neurological PC (r=0.95; ICC: 0.96) and normal feet (r=-0.97; ICC: 0.94). Also, intraobserver (r=0.95, r=0.76, r=0.82 and r=0.92 for FAO >0%, from -7% to 0%, from -13% to -7%, and <-13%, respectively) and interobserver reliability for FAO measurements (ICC: 0.78, ICC: 0.76, ICC: 0.85 and ICC: 0.92) scored excellent regardless of the deformity.Conclusion:This study confirms that three-dimensional semiautomatic tools used on weightbearing CT datasets have excellent intra and interobserver reliability in the assessment of hindfoot alignment in pes cavovarus. The nature and severity of the deformity does not affect the reliability of the measurements. This infers that these 3D biometric tools on WBCT images can be reliably used in severe neurological cavovarus feet to evaluate and monitor cavovarus deformity and assess response to intervention.

Alteration of Hindfoot Axis After Total Knee Arthroplasty

BackgroundIt has been shown that total knee arthroplasty (TKA) can correct the alignment of the lower limb, not only correcting the knee axis, but also affecting the alignment of the hindfoot. However, there is still not a significant amount of work in the literature. MethodsA prospective study was carried out in which 72 patients were radiographically (long axial view of the hindfoot) and clinically (American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale) evaluated before and 3 months after TKA. We investigated whether there were any significant associations between measurements of the axes, hindfoot angle, and AOFAS score with the type of deviation of the patient’s axis. ResultsFor the subgroups “hindfoot valgus-knee valgus,” “hindfoot valgus-knee varus,” and “hindfoot varus-knee valgus,” a reduction in angle after surgery was observed; for the cases “hindfoot varus-knee varus,” an increase in angle after surgery was observed. However, the Wilcoxon test showed that only the changes in the hindfoot axis of the “hindfoot varus-knee valgus” subgroup are statistically significant (P < .05). After surgery, the Wilcoxon test showed that the AOFAS score changes are statistically significant for all subgroups for which it was possible to perform the test (P < .05). ConclusionTKA promotes changes in the postoperative hindfoot axis, significantly in patients with knee valgus and hindfoot varus. In addition, TKA provides significant improvement in the postoperative AOFAS score. Level of EvidenceIIB.

The hind- and midfoot alignment computed after a medializing calcaneal osteotomy using a 3D weightbearing CT.

A medializing calcaneal osteotomy (MCO) is a surgical procedure frequently performed to correct an adult acquired flatfoot (AAFD) deformity. However, most studies are limited to a 2D analysis of 3D deformity. Therefore, the aim is to perform a 3D assessment of the hind- and midfoot alignment using a weightbearing CT (WBCT) preoperatively as well as postoperatively. Eighteen patients with a mean age of 49.4years (range 18-67) were prospectively included in a pre-post-study design. A MCO was performed and a WBCT was obtained pre- and postoperative. Images were converted into 3D models to compute linear and angular measurements, respectively, in millimeters (mm) and degrees (°), based on previously reported landmarks of the hind- and midfoot alignment. A regression analysis was performed between the displacement of a MCO and the obtained postoperative correction. The mean 3D hindfoot angle improved significantly preoperative compared to postoperative (p < 0.001). This appeared according to a linear relation with the amount of medial translation in a MCO (R2 = 0.84, p < 0.001). The axes of the tibia showed significant coronal as well as axial changes (p < 0.05). Analysis of the midfoot showed significant changes in the navicular height and rotation as well as the Méary angle (p < 0.05). Additionally, a linear trend between the midfoot measurements and amount of medial translation in a MCO was observed, but not significant (p > 0.05). This study demonstrates an effective 3D correction of an AAFD by a MCO according to a linear relationship. The concomitant formula can be used to perform a preoperative planning. The novelty is the comparative 3D weightbearing CT assessment of both the computed hind- and midfoot alignment after a medializing calcaneus osteotomy. This could improve accuracy of the currently performed preoperative planning in clinical practice.

Injury Pattern in Ligamentous Lisfranc Injuries in Competitive Athletes.

We report data on the largest cohort to date of patients who sustained a ligamentous Lisfranc injury during sport. To date, the prevalence of concurrent intercuneiform ligament injuries in the competitive athlete with subtle Lisfranc instability has not been reported. Eighty-two patients (64 males, 18 females) sustained an unstable Lisfranc injury (49 left, 33 right) and met inclusion criteria. Injuries were classified as traditional dislocation (TRAD, first to second TMT ligament tear), medial column dislocation (MCD, second TMT, and medial-middle cuneiform ligament tear), or proximal extension dislocation (PE, first, second, and medial-middle cuneiform ligament tear) and the injury pattern confirmed at surgery. All athletes underwent open reduction with internal fixation (ORIF) of each unstable midfoot segment. Fisher exact tests and 2-tailed t tests were used to analyze statistical significance according to injury pattern, sport, gender difference, hindfoot angle alignment, and injured side ( P < .05). Average age of athletes was 21.0 ± 5.3 years old (range 12-40), and return to sports was 7.5 ± 2.1 months. Injury distribution was as follows: TRAD (n = 40), MCD (n = 17), and PE (n = 23). MCD trended toward a longer return to sport (8.4 ± 3.3 months, P = .074). Football was the most common sport at time of injury (n = 48). Wakeboard athletes (n = 5) were older (31.4 ± 3.2, P = .0002), and MCD tears were more prevalent among them ( P = .061). Basketball (n = 13) players were significantly younger (19.1 ± 2.5 years, P = .028) and returned to sports quicker (5.2 ± 0.7, P = .0002). Return to sport data indicated a typical population for athletes with Lisfranc injury in these sports. Proximal extension disruption (intercuneiform ligament tear) occurred in 50% of these low-energy Lisfranc athletic injuries. MCD and PE may be more prevalent than previously understood. This is the first study to document the extent, pattern, and prevalence of associated intercuneiform ligament tears in the competitive athlete with a low-energy subtle, unstable Lisfranc injury. Level IV, retrospective case series.

Tibiotalocalcaneal Arthrodesis Using a Straight Intramedullary Nail

Category: Hindfoot Introduction/Purpose: Tibiotalocalcaneal (TTC) arthrodesis using a hindfoot intramedullary nail has been shown to be a safe and reliable technique in patients with severe ankle and hindfoot disease. There is debate about the use of straight nails versus curved nails. Proponents of the curved nail argue that straight nails predispose to greater risk of lateral plantar nerve injury, poor calcaneal bone purchase and inability to maintain satisfactory hindfoot valgus alignment. However, the subtalar joint is a condyloid joint enabling rotation of the talus on the calcaneum to create varus/valgus position of the calcaneal tuberosity. We present a clinical series of patients undergoing TTC fusion using a straight nail assessed by clinical and radiological outcomes to establish whether theoretical risks of straight nails are reflected in clinical practice. Methods: This single centre, retrospective study of prospectively collected data on a sequential series of patients to undergo TTC fusion, with pre and post-operative weight bearing CT imaging. Data was collected on indication for procedure, co-morbidities, post-operative complications, union rate as well as clinical scores, EQ5D and MOXFQ. Weight bearing CT imaging was analysed using the validated TALUS™ (torque ankle lever arm system) method on weight bearing CT, providing calcaneal offset, hindfoot angle and hindfoot alignment. These were used as markers of hindfoot alignment. Results: 65 patients (37 males, 28 females) were included in the study, with an average age of 57 years. Average follow-up was 20 months. Indications for TTC fusion included Charcot arthropathy, talar avascular necrosis, post traumatic arthritis and non-union of previous arthrodeses. Union rate was 91% (59/65). Overall complication rate was 11% (7/65) and most were minor wound complications. There were no plantar nerve injuries noted. There were no nail cut outs from the calcaneum. On all markers of hindfoot alignment, cases showed a more physiological degree of hindfoot valgus compared to pre-operative measures. There were significant improvement in both EQ5D and MOXFQ scores (p&lt;0.05). Conclusion: We present the largest series of TTC fusion using a straight intramedullary nail and the first series to analyse hindfoot alignment using weight bearing 3D CT imaging. Our data regarding correction of hindfoot alignment is supported by biomechanical theories of subtalar varus/valgus, being related to rotatory changes at the subtalar joint, questioning the perceived need for a curved nail. This is particularly at the level of the entry point of the nail. The principles of valgus hindfoot nails are based on biomechanical laboratory studies and cadaveric studies, neither of which reflect our findings in clinical practice.

Lateralizing Calcaneal Osteotomies and Their Effect on Calcaneal Alignment: A Three-Dimensional Digital Model Analysis.

Few authors have directly compared multiple types of lateralizing calcaneal osteotomies (LCOs) in terms of their ability to achieve deformity correction. The aim of this research was to use a digital model of a varus hindfoot to compare 4 different LCOs in terms of deformity correction and amount of tuberosity lateralization required. The authors hypothesis was that osteotomies involving a wedge resection would achieve greater correction with less lateralization. A weightbearing computed tomographic scan of a patient with a varus hindfoot deformity was used to construct a 3-dimensional digital model of the hindfoot, preserving weightbearing alignment. Four different LCOs were modeled: a standard oblique osteotomy, a Dwyer osteotomy, a modified Dwyer osteotomy involving lateralization in addition to wedge resection, and a Malerba Z-type osteotomy with wedge resection and lateralization. Incremental corrections were performed with each osteotomy type, and amount of correction was assessed with a vertical hindfoot angle and measurement of the lateral translation of the most inferior aspect of the calcaneus. Calcaneal length and osteotomy contact surface area were also measured. The modified Dwyer osteotomy led to the greatest improvements in the vertical hindfoot angle and lateral translation, followed by the Malerba osteotomy. The standard and Malerba osteotomies allowed the most preservation of calcaneal length; the Malerba and Dwyer osteotomies had the greatest contact surface area. LCOs that involve wedge resection as well as lateralization were able to achieve the greatest correction of hindfoot varus. For the surgical treatment of cavovarus foot deformities, osteotomies with wedge resection in addition to lateralization enable more powerful correction.