Normal Foot and Ankle Radiographic Angles, Measurements, and Reference Points

Intraoperative Radiographic Rotational Profile of the Tibia: Technique and Clinical Series

SUMMARY

Recreating tibial torsion in patients with complex tibial fractures is an important intraoperative consideration, particularly for fractures with comminution or segmental bone loss. Failure to accurately restore tibial alignment may lead to malrotation, poor functional outcomes, and reoperation to correct rotational deformity. No consensus currently exists regarding the optimal technique for intraoperative measurement of tibial torsion in patients undergoing tibial fracture fixation. This article describes a technique using a mobile C-arm fluoroscope to intraoperatively measure torsion of the contralateral uninjured leg to guide surgical fixation of the fractured tibia. The rotational profile of the uninjured leg is produced by obtaining a perfect lateral of the knee followed by an ankle mortise view. A series of patients is also presented that demonstrates the reproducibility of the technique and demonstrates the range of tibia torsion in patients with tibia fractures.

Comparison of different surgeries for correction of fixed flatfoot deformity studied through a dynamic model

Different surgeries are used to treat stage III Adult Acquired Flatfoot Deformity. Some include hindfoot manipulation with subtalar fusion (single fusion), triple fusion (subtalar, talonavicular, and calcanealcuboid), and triple fusion with additional midfoot and forefoot manipulation. This study aimed to compare the effect of these surgeries on the unloaded and loaded foot, using a validated dynamic computational model. Five patients with stage III flatfoot underwent pre-surgical and post-surgical CT scans. Dynamic computational models were created for four groups: pre-operative, single fusion, triple fusion, and triple fusion with additional maneuver. A control group was based on models from nine cadaveric normal feet. Once the effect of the surgeries on foot architecture was assessed, the response of the foot to bodyweight was evaluated. All surgeries changed the unloaded foot architecture towards normal. Triple fusion following the additional manipulation produced the best correction, but reduced talonavicular coverage. Under bodyweight, it was observed that, for the triple fusion surgeries, particularly after additional manipulation, foot rigidity and contact forces under the fourth and fifth metatarsal bones increased. Moreover, all surgeries moved the tibiotalar contact position to an area previously reported to have a lower risk of osteoarthritis. Clinical significance: the study results suggest that single fusion surgery corrects the deformity, with less risk of overcorrection, compared to the other techniques. However, triple fusion is necessary when osteoarthritis affects the Chopart joint.

Rate of bony union after Jones fracture fixation in the general population

Nonunion rates in the conservative treatment of Jones fractures can be high, therefore surgical intervention is often recommended. Most current studies in the literature look at a younger athletic population to assess bony union rates. Little has been published on healing rates in the general population. A retrospective chart review was performed of all patients undergoing surgical fixation of Jones fractures by three surgeons from 2015 to 2022. A total of 195 patients were collected. Radiographs were evaluated to determine time to fracture union, type of fixation construct, and risk factors for development of the fracture such as pes cavus and forefoot adduction. The bony union rate was 92.8 % with a nonunion rate of 7.2 % (14/195), a delayed union rate of 10.3 % (20/195), and a refracture rate of 4.1 % (8/195). The overall time to union was 14 weeks, with a median of 11 weeks in patients less than 30 years of age and 14 weeks in those greater than 30 years of age. Pes cavus was present in 42.1 % of patients and forefoot adduction in 32.8 %. Patients with increased age (p < 0.001) and type II diabetes (p = 0.04) were found to have statistically significant longer times to union. Metatarsus adductus was a significant predictor of nonunion status (p = 0.015). The primary aim of this study was to evaluate the healing rates of Jones fractures after fixation in the general population.

Association of calcaneal pitch angle with recurrence of postoperative hallux valgus in patients with rheumatoid arthritis

Hallux valgus (HV) and flatfoot deformities are frequently seen in patients with rheumatoid arthritis (RA). This study aimed to determine whether flatfoot deformity contributes to the recurrence of HV in RA patients. This study examined 62 feet from 45 RA patients who were diagnosed with HV and underwent the first metatarsal joint-preserving surgery between November 2010 and October 2021. Recorded data included age at surgery, sex, disease duration, body mass index [BMI], RA disease duration, medical treatment of RA, Larsen grade, blood test, pre/postoperative Japanese Society for Surgery of the Foot, HV angle, M1M2 angle, M1M5 angle, calcal pitch angle, and Meary's angle. HV recurrence on radiography was defined as an HV angle exceeding 20°. HV recurrence was observed in 17 feet. Significant differences were observed due to risk factors such as BMI, disease duration, Larsen grade 4-5, and preoperative calcaneal pitch angle. Multivariate logistic regression analysis identified that lower BMI, a higher M1M2 angle, and a lower calcaneal pitch angle are preoperative risk factors for the recurrence of postoperative HV in RA patients. LEVEL OF EVIDENCE: 3.

A comparison of clinical and radiographic outcomes between isolated total talus replacement and combined total talus replacement with total ankle arthroplasty or hindfoot arthrodesis

Total talus replacement (TTR) is a viable surgical option in the setting of talar avascular necrosis and collapse, as well as a revision option for failed total ankle arthroplasty with talar implant subsidence. The purpose of the present study was to compare the clinical and radiographic outcomes following isolated TTR and TTR combined with total ankle arthroplasty or hindfoot arthrodesis. Patients who underwent TTR were retrospectively reviewed, as a multicenter consecutive case series. Basic demographic data, comorbidities and surgical date were collected. Medical records were reviewed to obtain postoperative and preoperative visual analog scale (VAS) scores, American Orthopedic Foot and Ankle society (AOFAS) outcome scores, postoperative complications and radiographic measurements. Statistical analysis was conducted to compare radiographic and patient-reported outcomes pre- and postoperatively. Thirty-six patients underwent TTR with mean follow-up of 25.39 months. VAS pain scores improved postoperatively from 8.43 to 2.67 (P <0.001). AOFAS improved postoperatively from 36.33 to 81.78 (P < 0.001). There was an overall improvement in talar arc length (P = 0.035), talar width (P = 0.0037), talar height (P < 0.001), Bohler's (P < 0.001) and Gissane's angle (P = 0.004). The overall complication and subsequent surgery rate were each 16.7 %. The TTR implant survivorship rate was found to be 94.5 %. When comparing outcome scores between Isolated TTR and Combined TTR, no significant differences were detected in the degree of improvement. Both isolated and combined TTR provide a suitable and safe option for the treatment of advanced talar AVN or associated tibiotalar and hindfoot arthritis.

The position, orientation and morphology of the peroneus longus tubercle in hallux valgus - A weight-bearing CT assessment

BACKGROUND

Hallux valgus (HV) may be associated with a dysfunctional peroneus longus, however there is very little research into the link between these pathologies. The peroneus longus tubercle (PLT) may serve as a surrogate marker for peroneus longus function. Our objective was to compare the position, orientation and morphology of the PLT in feet with and without HV.

METHODS

In this single center series, we analyzed weight-bearing CT scans of 20 feet (12 patients) with HV and 20 feet (12 patients) without HV. Groups were age matched. We compared differences between groups for recently reported measurements assessing the PLT: tubercle-to-floor distance (T-F distance), bisecting angle of the PLT, tubercle-to-metatarsals angle (T-MT angle), and cross-sectional areas and roundness of the PLT.

RESULTS

The T-F distance was significantly lower in the HV group (p = 0.001). The bisecting angle was lower (less vertical) in the HV group (p = 0.017). T-MT angle was lower in the HV group (p = 0.041). There was no difference in the cross-sectional area or roundness of the PLT between groups.

CONCLUSION

We found patients with HV had differences in orientation of the PLT (with a less vertical tubercle). This could indicate a relationship between direction of pull of the peroneus longus and HV. There were no differences in size of the PLT suggesting strength of the peroneus longus may not play a role in developing HV. Further research is needed to build upon this preliminary work and determine the link between the observed differences and the pathogenesis of HV.

Standardizing 3 Dimensional Measurements in Foot and Ankle Imaging: A Contemporary Review and Methodological Proposal

Increasing utilization of weight-bearing computed tomography and fluoroscopy has driven the need for standardization of 3 dimensional (3D) measurements in the foot and ankle. These emerging imaging modalities are currently used to evaluate foot and ankle conditions including ankle osteoarthritis, progressive collapsing foot deformity, midfoot instability, and hallux valgus. This study aims first to provide a comprehensive review of clinical studies that have utilized these 3D methodologies. As a second goal, this study presents the methodological approach proposed by an international task force of experts toward addressing those concerns to provide validated guidelines for 3D static and dynamic measurements.

Fibular Malunion: Diagnosis, Treatment, and Prevention

Malunions of the fibula are caused by malreduction during initial surgical management or the result of nonoperative treatment of an unstable ankle fracture. They can cause significant changes in loading of the ankle and subsequently lead to arthritic changes. Timely recognition of abnormal anatomy and corrective osteotomy yields favorable results. The current review addresses the anatomy and biomechanics of the ankle and the effects of a malunited fibula fracture. The radiological workup is discussed as well as the technique of the osteotomy. Last, the authors highlight the expected outcome and possible complications for an optimal informed consent of the patient.

Lateral Displacement Calcaneal Osteotomy Combined With Anterolateral Transfer of the Tibialis Posterior Tendon for Treating Flexible Cavovarus Foot in an Adult Patient: A Case Report

The cavovarus foot is a spectrum of foot deformity primarily caused by muscular imbalance and characterized by increased pitch, varus of the hindfoot, plantar flexion of the midfoot, and pronation and adduction of the forefoot. Surgery for cavovarus foot commonly involves some combination of procedures, however, no consensus has emerged regarding their choice. We report the case of a 68-year-old male with a flexible cavovarus foot. The patient complained of pain in the subtalar joint and plantar callosities. For this patient, we performed lateral displacement calcaneal osteotomy (LDCO), anterolateral transfer of the tibialis posterior tendon (TPT), and dorsiflexion first metatarsal osteotomy (DFMO). At one year and nine months after surgery, plain radiographs revealed bony union at the osteotomy sites of the calcaneus and first metatarsal. The Japanese Society for Surgery of the Foot hindfoot scale and visual analogue scale improved from 52 points preoperatively to 82 points at the final follow-up and from 3 points to 1 point, respectively. A combination of LDCO, TPT, and DFMO is effective for adult patients with flexible cavovarus foot.

The reliability of talonavicular uncoverage to indicate forefoot abduction in progressive collapsing foot deformity: a finite element analysis

BACKGROUND

Progressive Collapsing Foot Deformity (PCFD) presents various deformities. While medializing displacement calcaneal osteotomy (MDCO) and lateral column lengthening (LCL) are commonly employed as corrective surgeries, their impact on foot structure and functionality necessitates detailed biomechanical analysis. The objective of this study is to analyze the reliability of using talonavicular uncoverage percentage (TUP) as a metric for assessing the degree of forefoot abduction.

METHODS

Seven subject-specific flatfoot models were constructed based on previous study. Finite element analysis was conducted to simulate stress distribution and contact characteristics in PCFD. Models were categorized based on TUP values, and MDCO was performed to analyze stress changes in the medial longitudinal arch and contact characteristics of subtalar joint.

RESULTS

The study revealed discrepancies in TUP measurements between plain radiographs and three-dimensional models. Comparative analysis of the seven models showed that TUP exceeding 40% showed varied stress responses. A newly introduced parameter, the distance from the center of the head of the second metatarsal to the talar body axis (DSMT), demonstrated potential as a more dependable indicator. Models with DSMT below 20 mm experienced a remarkable reduction in ligamentous stress and notable change in region of stress concentration on the subtalar joint surface after MDCO, while those above 20 mm showed no noteworthy change.

CONCLUSION

The study suggests that TUP may not be a reliable indicator for LCL surgery in PCFD, highlighting the need for improved assessment parameters. DSMT shows promise as a more dependable indicator, warranting further research to validate its efficacy. Enhanced indicators will facilitate better surgical planning in PCFD corrective procedures.

CLINICAL RELEVANCE

Accurate assessment of flatfoot deformities is crucial for developing effective treatments. DSMT , which utilizes the talar body axis as a reference, is not affected by anatomical variations in the talar head body angle, rendering it more reliable for assessment of forefoot abduc tion. Improved indicators will contribute to better surgical decision making and patient outcomes in PCFD.

Hallux valgus and pes planus: Correlation analysis using deep learning-assisted radiographic angle measurements

BACKGROUND

The relationship between hallux valgus (HV) and pes planus remains unresolved. This study aims to determine the correlation between HV and pes planus using a deep learning (DL) model to measure radiographic angle parameters.

METHODS

In total, radiographs of 212 feet detectable by the DL model were analyzed. HV was evaluated using the hallux valgus and intermetatarsal angles, while pes planus was assessed using the lateral talo-first metatarsal (Meary's) and calcaneal pitch angles. Correlation analyses were performed for each DL model-measured angle parameter. We investigated whether pes planus worsened with increasing severity of HV and vice versa.

RESULTS

All parameters were significantly correlated with each other. Pes planus worsened with increasing severity of HV, and as the severity of pes planus increased, HV also worsened.

CONCLUSION

Utilizing the DL model-assisted radiographic angle measurements, this study established a significant correlation between HV and pes planus.

LEVEL OF EVIDENCE

III.

The association between varus knee deformity and morphological changes in the foot and ankle in patients with end-stage varus knee osteoarthritis

BACKGROUND

This study aimed to (1) determine the association between varus knee deformity and ipsilateral foot and ankle morphology, and (2) evaluate the relationship between varus knee deformity and foot and ankle pain in patients with end-stage varus knee osteoarthritis (KOA).

METHODS

A total of 213 patients who underwent primary total knee arthroplasty for end-stage varus KOA were enrolled in this study and divided into a 'severe varus group' (n = 119) and a 'mild varus group' (n = 94) based on preoperative knee varus degree. Morphological parameters and pain incidence in the foot and ankle were compared between the two groups. The correlation between knee varus and foot and ankle morphology was analyzed.

RESULTS

Significant differences in ankle morphology were observed between the two groups. The deformity magnitudes of the hindfoot valgus (P < 0.001) and hallux valgus (HVA, P = 0.028; IMA, P = 0.046) were significantly higher in the severe varus group. Additionally, the incidences of ankle osteoarthritis (OA) (P = 0.005) and hallux valgus (P = 0.028) were higher in the severe varus group. Patients with severe KOA were more likely to experience medial ankle pain (P = 0.023), hindfoot pain (P = 0.034), and multiple pain locations (P = 0.015).

CONCLUSION

Varus knee deformity was associated with morphological changes in the foot and ankle, and the incidence of ankle OA and hallux valgus deformity was significantly higher in patients with severe varus KOA. Patients with severe varus KOA were more prone to medial ankle pain, hindfoot pain, and multiple pain locations, which were associated with corresponding morphological changes.

Anatomical insights into medial-sided talar dome osteochondral lesions: a comparative analysis of unilateral and bilateral cases and healthy controls using MRI measurements

BACKGROUND

The etiology of medial-sided talar osteochondral lesions (OCLs) remains insufficiently understood.

PURPOSE

To identify anatomical risk factors contributing to the development of unilateral or bilateral OCL of the talus on the medial side, utilizing morphological parameters derived from magnetic resonance imaging (MRI).

MATERIAL AND METHODS

In this retrospective study, 24 ankle MRI scans from 12 patients exhibiting bilateral OCLs of the talar dome on the medial side, 24 ankle MRIs from 24 patients with unilateral medial-sided OCLs, and 24 healthy controls matched for age, sex, and side within each group were analyzed. Six distinct MRI parameters were measured: the anterior opening angle of the talus (AOT); tibial axis-medial malleolus angle (TMM); plafond-malleolar angle (PMA); anterior talofibular ligament-posterior talofibular ligament (ATFL-PTFL) angle; the ratio of the distal tibial articular surface to the length of the trochlea tali arc (TAS/TAL); and the depth of the incisura fibularis (IncDep).

RESULTS

The AOT, ATFL-PTFL angle, and TMM of individuals in both the bilateral and unilateral groups were significantly higher when compared to the healthy controls. In addition, TMM measurements in the unilateral group were significantly higher than in the bilateral group.

CONCLUSION

AOT and TMM appeared to be the primary predisposing factors in the development of both unilateral and bilateral OCLs. Furthermore, TMM shows a greater increase in unilateral OCL cases compared to bilateral OCL cases. The fact that TMM is not significantly high in known unilateral OCL cases can be a stimulus for investigating the other ankle for OCL.

The Association Between Foot Morphology and Foot Loading During Gait

The perceived association between foot type and injury risk has inspired the development of many foot typing methods. The purpose of this study was to determine how well different foot typing methods explained variations in regional foot loading in asymptomatic adults during gait, while considering age, sex, and walking speed as covariates. Six methods were used to determine foot type in 92 asymptomatic adults. An insole pressure sensor system measured peak force and force-time integral during treadmill walking at a self-selected pace. The foot was divided into nine regions and the association between foot type and foot loading was analyzed using generalized estimating equations (GEE) while accounting for the covariates. Over an average of 250 steps per individual, the results demonstrated variability in the association between regional foot loading and foot type. Specifically, Arch Index and X-Ray Arch Type correlated with hindfoot and midfoot loading, while Foot Posture Index correlated with medial midfoot, forefoot, and toe loading. Calcaneal Pitch and Meary's Angle correlated with medial hindfoot, midfoot, and forefoot loading, while Varus/valgus angle correlated with loading in the forefoot and toes. The location and direction of associations were generally similar for Calcaneal Pitch, Meary's Angle, and X-Ray Arch Type, and opposite of Arch Index. The analyses demonstrated that walking speed, age, and sex were all important factors that affected the relationship between plantar loading and foot type. Specific foot type methods correlate better with loading in specific foot regions, potentially making them better to evaluate injury risk in those regions.

Contribution of the plantar fascia and long plantar ligaments to the stability of the longitudinal arch of the foot

The contribution of the Plantar Fascia (PF) and Long Plantar Ligament (LPL), two ligaments extending from the hindfoot to the forefoot, to arch stability has been studied in the past using in vivo, in vitro, and in silico methodologies. In silico studies were based on one single model obtained from one single subject and did not account for the known inter-subject morphological and biomechanical variations. In the present study, we developed computational dynamic models of nine different legs obtained from nine different individuals to evaluate the role of the LPL and PF in arch support, accounting for biological differences between subjects. These models were validated by comparing the simulation results against experimental results from the corresponding cadaver legs. After validation, we simulated body weight conditions for each model by applying a vertical load to the tibia, starting from zero and increasing linearly to 720 N. Kinematic and dynamic parameters, including the variation of the medial arch angle and of the navicular height, as well as the passive forces developed by the LPL and PF, were used to evaluate the contribution of these ligaments to arch support under body weight. The results indicate that a total collapse of the medial longitudinal arch occurred only when both the LPL and PF were absent, but a stable arch was maintained when either one of these two ligament structures were present. The results varied significantly among the specific models, highlighting the importance of using multiple models to account for inter-subject morphological differences.

The position, orientation, and relative size of the fibularis longus tubercle in normal patients: A weightbearing CT assessment

The fibularis longus attaches to the base of the first metatarsal at the fibularis/peroneus longus tubercle (FLT/PLT). Theoretically, differences in FLT morphology may reflect changes in the function of the fibularis longus. This study defines the normal limits of the FLT position, orientation, and size in patients with morphologically normal foot anatomy. A retrospective analysis of 131 feet without deformity in 72 patients undergoing weightbearing CT (WBCT) at a single center was conducted. The position and morphology of the FLT was assessed with novel measurements including tubercle-floor distance, tubercle-metatarsal angle, and the angle between the floor and a line bisecting the FLT (bisecting angle). Roundness of the FLT was compared to a triangle limiting its shape (triangular ratio), with lower values indicating increasing roundness. We also report relative size of the FLT to the first metatarsal (X/Y ratio), and relative size of the first metatarsal and FLT to the second metatarsal (XY/Z ratio). There were no significant side to side differences for any measurement (p > 0.05). Mean values were: tubercle-floor distance 28.02 ± 2.63 mm, tubercle-metatarsal angle 32.7 ± 6.32 degrees, bisecting angle 65.58 ± 6.27 degrees, triangular ratio 0.69 ± 0.04, X/Y ratio 1.13 ± 0.20, and XY/Z ratio 3.44 ± -0.72. Bisecting angle strongly correlated with tubercle-metatarsal angle (Pearson correlation 0.840, p < 0.001) suggesting FLT rotation occurred independent of foot position. ICC was >0.943 for all measurements. This study reports the morphology of the FLT in individuals with normal feet. This normative data may be used in future studies examining differences between groups of patients with foot pathology, helping us better understand the role of fibularis longus in the development and treatment of foot disorders.

Validation of patient-specific flatfoot models on finite element analysis

Adult-acquired flatfoot causes various deformities. If a patient-specific foot model can be created using the finite element method, it can be used to study the appropriate surgical technique for each patient. Nine patient-specific flatfoot models were created, and loading simulations were performed. To validate the models, the patients' weight-bearing radiographs were compared with the parameters of the models. The CCC values ranged from 0.917 to 0.993 , all exceeding the moderate threshold according to the McBride criteria. Our model reproduces the biomechanics of a patient's foot under loading conditions, which may be useful for investigating patient-specific surgical procedures.

Talar and Calcaneal Coordinate Axes Definitions across Foot Pathologies

The understanding of foot and ankle biomechanics is improving as new technology provides more detailed information about the motion of foot and ankle bones with biplane fluoroscopy, as well as the ability to analyze the hindfoot under weightbearing conditions with weightbearing computed tomography. Three-dimensional anatomical coordinate systems are necessary to describe the 3D alignment and kinematics of the foot and ankle. The lack of standard coordinate systems across research study sites can significantly alter experimental data analyses used for pre-surgical evaluation and post-operative outcome assessments. Clinical treatment paradigms are changing based on the expanding knowledge of complex pes planovalgus morphologies or progressive collapsing foot deformity, which is present in both neurologic and non-neurologic populations. Four patient cohorts were created from 10 flexible PCFD, 10 rigid PCFD, 10 adult cerebral palsy, and 10 asymptomatic control patients. Six coordinate systems were tested on both the talus and calcaneus for all groups. The aim of this study was to evaluate axes definitions for the subtalar joint across four different patient populations to determine the influence of morphology on the implementation of previously defined coordinate systems. Different morphologic presentations from various pathologies have a substantial impact on coordinate system definitions, given that numerous axes definitions are defined through geometric fits or manual landmark selection. Automated coordinate systems that align with clinically relevant anatomic planes are preferred. Principal component axes are automatic, but do not align with clinically relevant planes and should not be used for such analysis where anatomic planes are critical.

Outcomes of the "Calcaneo-stop" procedure for treating symptomatic flexible flatfoot in children: A systematic review and meta-analysis of 2394 feet

BACKGROUND

This study evaluates the efficacy of the calcaneo-stop (C-Stop) procedure's effectiveness in treating symptomatic flexible flatfoot (FFF) in children.

METHODS

A systematic review and meta-analysis were conducted using PubMed, Embase, and Cochrane databases to identify studies until 2023 on the outcomes of the C-Stop procedure in children with FFF. The risk of bias was assessed using MINORS criteria.

RESULTS

Of 85 studies screened, 20 involving 2394 feet from 1415 patients (mean age 11.2 ± 1.3 years) were included. Post-procedure, significant improvements were noted in pain reduction (93.5%), heel alignment (95.21%), and radiological measures, including reductions in Kite (7.32º), Meary (11.65º), Costa-Bartani angles (17.11º), talar declination (12.63º) and increase in Calcaneal Pitch Angle (5.92º). AOFAS scores increased by 22.32 points on average, with 94.83% reporting high satisfaction. Complication rate was low (7.8%).

CONCLUSIONS

The C-Stop procedure is effective for treating FFF in children, offering significant clinical, radiological, and functional improvements with high patient satisfaction and a low complication rate.

LEVEL OF EVIDENCE

Level IV, Systematic review of Level-IV studies.

Preoperative increased pronation angle of the first metatarsus associated with correction loss after hallux valgus surgery: A semi-weight-bearing computed tomography study

BACKGROUND

The effect of preoperative first metatarsal pronation on postoperative prognosis of hallux valgus (HV) surgery is under investigation. Utilizing semi-weight-bearing computed tomography, the preoperative pronation angle was assessed to quantify its impact on postoperative prognosis.

METHODS

In a retrospective analysis of 31 feet, those with re-increased hallux valgus angle postoperatively were classified as the non-maintained group, and the remainder as the maintained group. Preoperative pronation angles were compared to establish a threshold. Subsequently, feet were re-classified into high or low-pronation categories. The relative risk of non-maintenance in high-pronation category was calculated.

RESULTS

The non-maintained group exhibited a significantly higher preoperative pronation angle (p = 0.021), with a 28.4º threshold. The high-pronation category had a relative risk of 2.34 for non-maintenance.

CONCLUSIONS

Increased preoperative first metatarsal pronation angle is associated with correction loss after HV surgery. Utilizing sWBCT to measure the pronation angle provides valuable insights into postoperative prognosis.

LEVEL OF EVIDENCE

III.

Development and validation of a fully automated tool to quantify 3D foot and ankle alignment using weight-bearing CT

INTRODUCTION

Foot and ankle alignment plays a pivotal role in human gait and posture. Traditional assessment methods, relying on 2D standing radiographs, present limitations in capturing the dynamic 3D nature of foot alignment during weight-bearing and are prone to observer error. This study aims to integrate weight-bearing CT (WBCT) imaging and advanced deep learning (DL) techniques to automate and enhance quantification of the 3D foot and ankle alignment.

METHODS

Thirty-two patients who underwent a WBCT of the foot and ankle were retrospectively included. After training and validation of a 3D nnU-Net model on 45 cases to automate the segmentation into bony models, 35 clinically relevant 3D measurements were automatically computed using a custom-made tool. Automated measurements were assessed for accuracy against manual measurements, while the latter were analyzed for inter-observer reliability.

RESULTS

DL-segmentation results showed a mean dice coefficient of 0.95 and mean Hausdorff distance of 1.41 mm. A good to excellent reliability and mean prediction error of under 2 degrees was found for all angles except the talonavicular coverage angle and distal metatarsal articular angle.

CONCLUSION

In summary, this study introduces a fully automated framework for quantifying foot and ankle alignment, showcasing reliability comparable to current clinical practice measurements. This operator-friendly and time-efficient tool holds promise for implementation in clinical settings, benefiting both radiologists and surgeons. Future studies are encouraged to assess the tool's impact on streamlining image assessment workflows in a clinical environment.

Arthroscopic Management of Melorheostosis-Induced Ankle Deformity: A Case Report

Melorheostosis is a rare congenital sclerosing bone dysplasia characterized by a distinctive "candle-like flowing wax" radiological appearance. This study presents a case of an 80-year-old male who presented with a decade-long history of left ankle pain and rigid equinus deformity, which substantially impaired his mobility and activities of daily living. Conservative interventions, including physical therapy and custom orthotics, failed to alleviate his symptoms. Subsequent arthroscopic osteotectomy and Achilles tendon lengthening engendered substantial postoperative improvements in pain relief, range of motion, and gait stability, enabling him to resume previous activities such as cycling. This study highlights the potential of minimally invasive surgical techniques in managing melorheostosis-related deformities to optimize patient outcomes and quality of life. Nevertheless, long-term follow-up is essential for assessing the risk of recurrent ankle deformity and the potential requirement for revision surgery.

Correlation of progressive collapsing foot deformity with varus knee alignment in young adults - A case control study

Background

Majority of patients with Progressive Collapsing Foot Deformity(PCFD) have symptoms pertaining to the knee. Malalignment at the foot will have effects on the alignment of the knee. In this case control study, we compare the alignment of the knees between patients with PCFD and controls.

Materials

Sixty subjects, 30 PCFD and 30 controls, underwent radiographs in which the tibiofemoral angle and radiological parameters of PCFD were assessed. Parameters of PCFD were correlated with the tibiofemoral angle.

Results

Mean tibiofemoral angle was 3.8° among the cases and 4.8° among the controls which was statistically significant(P = 0.001). Varus knee alignment was seen in 41 out of 60 limbs with PCFD which was statistically significant(P < 0.001). The tibiofemoral angle correlated significantly with the Meary angle(P = 0.03) and the talonavicular coverage angle(P = 0.003).

Conclusions

PCFD is associated with varus knee malalignment. This varus deformity early in adulthood may lead to deleterious effects like medial compartment osteoarthritis in later life. Early intervention for such patients may help avoid this knee damage.

Level of evidence

Level 3-prognostic.

Risk Factors for Midfoot Arthritis Associated With Medical History by Weight Bearing Computed Tomography

Tarso-metatarsal joints and naviculocuneiform joints comprising midfoot is the second most commonly involved joints following the first metatarsophalangeal joint in the foot. However, related factors of midfoot arthritis (MA) have been rarely reported. The bony structure and alignment can be more precisely assessed using Weight-Bearing Computed Tomography (WBCT) than conventional radiographs. Therefore, the aim of this study was to investigate risk factors for MA related to medical history and comorbid foot deformities using WBCT. WBCT data from September 2014 to April 2022 were extracted from a single referral hospital. All cases were divided into two groups by the presence of MA. Twenty-five potential related factors including demographics, etiology, and common co-occurring foot deformities were collected for comparison. Six hundred six cases (247 males and 359 females) among consecutive 1316 cases between September 2014 to April 2022 were selected. One hundred thirty-nine male cases (56.3%) and 210 female cases (58.5%) showed MA. In stepwise multiple logistic regression analysis, 5 factors remained statistically significant. The multivariate-adjusted odds ratios for age, laterality, body mass index (BMI), Progressive Collapsing Foot Deformity (PCFD), and lesser toe deformities (LTD) were 1.08, 1.54, 1.05, 6.62, and 3.03 respectively. Risk factors for MA associated with medical history and foot deformities included age, laterality, BMI, PCFD, and LDT.

Effects of Rhythm Step Training on Foot and Lower Limb Balance in Children and Adolescents with Flat Feet: A Radiographic Analysis

Background and Objectives: Owing to the recent reports regarding the efficacy of rhythm step training (RST) in lower limb muscle development and motor skill enhancement, this study aimed to evaluate the effects of RST on foot and lower limb balance in children and adolescents diagnosed with flat feet using radiographic analysis. Materials and Methods: A total of 160 children and adolescents diagnosed with flat feet from a hospital in Seoul were randomly assigned to the general flat feet training (GFFT) (n = 80) or RST (n = 80) group. Patients in both groups exercised for 50 min once a week for 12 weeks. Key variables, such as quadriceps angle (Q-angle), calcaneal pitch angle (CPA), calcaneal-first metatarsal angle (CFMA), and navicular-cuboid overlap ratio (OR) were measured before and after the intervention. Results: Significant improvements in Q-angle (p < 0.001), CPA (p < 0.001), CFMA (p < 0.001), and navicular-cuboid OR (p < 0.001) were observed in the RST group compared to the GFFT group. RST was found to be more effective in normalizing the biomechanical function of the calcaneus and improving lower limb function. Conclusions: RST significantly enhances foot and lower limb balance in children and adolescents with flat feet, suggesting its potential use as an effective intervention for this population. The study did not specifically analyze the effects of various components of rhythm training, such as music, exercise intensity, and frequency, on the outcomes. Further research is needed to determine how each of these elements individually influences the results.

Morphological changes in flatfoot: a 3D analysis using weight-bearing CT scans

BACKGROUND

Flatfoot is a condition resulting from complex three-dimensional (3D) morphological changes. Most Previous studies have been constrained by using two-dimensional radiographs and non-weight-bearing conditions. The deformity in flatfoot is associated with the 3D morphology of the bone. These morphological changes affect the force line conduction of the hindfoot/midfoot/forefoot, leading to further morphological alterations. Given that a two-dimensional plane axis overlooks the 3D structural information, it is essential to measure the 3D model of the entire foot in conjunction with the definition under the standing position. This study aims to analyze the morphological changes in flatfoot using 3D measurements from weight-bearing CT (WBCT).

METHOD

In this retrospective comparative our CT database was searched between 4-2021 and 3-2022. Following inclusion criteria were used: Patients were required to exhibit clinical symptoms suggestive of flatfoot, including painful swelling of the medial plantar area or abnormal gait, corroborated by clinical examination and confirmatory radiological findings on CT or MRI. Healthy participants were required to be free of any foot diseases or conditions affecting lower limb movement. After applying the exclusion criteria (Flatfoot with other foot diseases), CT scans (mean age = 20.9375, SD = 16.1) confirmed eligible for further analysis. The distance, angle in sagittal/transverse/coronal planes, and volume of the two groups were compared on reconstructed 3D models using the t-test. Logistic regression was used to identify flatfoot risk factors, which were then analyzed using receiver operating characteristic curves and nomogram.

RESULT

The flatfoot group exhibited significantly lower values for calcaneofibular distance (p = 0.001), sagittal and transverse calcaneal inclination angle (p < 0.001), medial column height (p < 0.001), sagittal talonavicular coverage angle (p < 0.001), and sagittal (p < 0.001) and transverse (p = 0.015) Hibb angle. In contrast, the sagittal lateral talocalcaneal angle (p = 0.013), sagittal (p < 0.001) and transverse (p = 0.004) talocalcaneal angle, transverse talonavicular coverage angle (p < 0.001), coronal Hibb angle (p < 0.001), and sagittal (p < 0.001) and transverse (p = 0.001) Meary's angle were significantly higher in the flatfoot group. The sagittal Hibb angle (B =  - 0.379, OR = 0.684) and medial column height (B =  - 0.990, OR = 0.372) were identified as significant risk factors for acquiring a flatfoot.

CONCLUSION

The findings validate the 3D spatial position alterations in flatfoot. These include the abduction of the forefoot and prolapse of the first metatarsal proximal, the arch collapsed, subluxation of the talonavicular joint in the midfoot, adduction and valgus of the calcaneus, adduction and plantar ward movement of the talus in the hindfoot, along with the first metatarsal's abduction and dorsiflexion in the forefoot.

First Metatarsal Rotation After Scarf Osteotomy for Hallux Valgus

BACKGROUND

Recurrence after surgical correction of hallux valgus may be related to coronal rotation of the first metatarsal. The scarf osteotomy is a commonly used procedure for correcting hallux valgus but has limited ability to correct rotation. Using weight-bearing computed tomography (WBCT), we aimed to measure the coronal rotation of the first metatarsal before and after a scarf osteotomy, and correlate these to clinical outcome scores.

METHODS

We retrospectively analyzed 16 feet (15 patients) who had a WBCT before and after scarf osteotomy for hallux valgus correction. On both scans, hallux valgus angle (HVA), intermetatarsal angle (IMA), and anteroposterior/lateral talus-first metatarsal angle were measured using digitally reconstructed radiographs. Metatarsal pronation angle (MPA), alpha angle, sesamoid rotation angle, and sesamoid position were measured on standardized coronal WBCT slices. Preoperative and postoperative (12 mo) clinical outcome scores (Manchester Oxford Foot Questionnaire and Visual Analogue Scores) were captured.

RESULTS

Mean HVA was 28.6 ± 10.1° preoperatively and 12.1 ± 7.7° postoperatively (P < .001). Mean IMA was 13.7 ± 3.8° preoperatively and 7.5 ± 3.0° postoperatively (P < .001). Before and after surgery, there were no significant differences in MPA (11.4 ± 7.7 and 11.4 ± 9.9°, respectively; P = .75) or alpha angle (10.9 ± 8.0 and 10.7 ± 13.1°, respectively; P = .83). There were significant improvements in sesamoid rotation angle (SRA) (26.4 ± 10.2 and 15.7 ± 10.2°, respectively; P = .03) and sesamoid position (1.4 ± 1.0 and 0.6 ± 0.6, respectively; P = .04) after a scarf osteotomy. There were significant improvements in all outcome scores after surgery. Poorer outcome scores correlated with greater postoperative MPA and alpha angles (r = .76 (P = .02) and .67 (P = .03), respectively).

CONCLUSION

A scarf osteotomy does not correct first metatarsal coronal rotation, and worse outcomes are linked to greater postoperative metatarsal rotation. Rotation of the metatarsal needs to be measured and considered when planning hallux valgus surgery. Further work was needed to compare postoperative outcomes with rotational osteotomies and modified Lapidus procedures when addressing rotation.Level of Evidence: 4.

Hallux Valgus Interphalangeus Measurement: Comparison of the 2 Radiographic Methods

BACKGROUND

To determine the reliability of Delta PP (difference in medial and lateral proximal phalanx wall length) compared with HIA (hallux interphalangeal angle) in the assessment of HVI (hallux valgus interphalangeus) in both preoperative and postoperative radiographs.

METHODS

This was a retrospective observational study of 186 feet with hallux valgus. The number of cases required to adequately power the study was 128. Preoperative and postoperative hallux alignment were evaluated by 2 different radiological parameters, Delta PP and HIA. Interobserver variability was assessed independently by 2 authors and compared using a intraclass correlation coefficient.

RESULTS

The intraclass correlation coefficient was more than 0.8 for all parameters, thus both HIA and Delta PP measurement provide reliable and reproducible data. Mean HIA significantly increased following surgical correction of hallux valgus. In comparison, the mean Delta PP decreased after correction. This postoperative increase in HIA indicates that preoperative HIA underestimates the magnitude of HVI and therefore is an inaccurate tool for measuring HVI's contribution to the TVDH (total valgus deformity of the hallux) and to preoperative planning. However, the Delta PP was a greater determinant of the phalanx deformity's contribution to the TVDH.

CONCLUSION

The outcome of our study shows that both HIA and Delta PP are reproducible when assessing the HVI deformity; however, Delta PP quantifies the amount of correction obtained more precisely. The additional benefit of measuring the Delta PP is that it allows for accurate planning in determining the dimensions of the medial-based wedge of the Akin osteotomy that needs to be resected.

LEVELS OF EVIDENCE

Level 4.

Electromyographic Analysis of Large Muscle Activity in Progressive Collapsing Foot Deformity

BACKGROUND

There are various deformities described in the spectrum of Progressive Collapsing Foot Deformity (PCFD) which not only have adverse effects on the foot but also on the entire lower limb. Early lower limb muscular fatigue and pain during exertion is the most common complaint of patients with PCFD. Surface electromyography (sEMG) provides an accurate assessment of muscle activity. In this study, we aim to compare the activities of quadriceps, hamstrings, and gastrosoleus muscle groups of adult patients with PCFD with normal lower limbs and correlate the radiological parameters and functional effects of PCFD with the activities.

METHODS

Thirty patients with bilateral PCFD and 30 controls underwent weight-bearing anteroposterior (AP), lateral, and hindfoot alignment radiographs of the foot. Radiographic parameters of PCFD were assessed. Surface electromyography was used to assess the quadriceps, hamstrings, and gastrosoleus activities, and this was compared between the 2 groups and correlated with radiological measurements of PCFD. Tegner activity questionnaire was used to assess the functional effects of collapsed arch.

RESULTS

Electrical activities of all muscle groups were significantly higher in cases than controls. Meary's angle and hindfoot moment arm had significant correlations with hamstring activity (P = .013) and gastrosoleus activity (P = .027), respectively. Tegner scores of cases were significantly lower than those of controls (P = .041).

CONCLUSIONS

The PCFD causes an increase in activity of large muscles of the affected lower limb which act on joints other than those in the foot. This finding may be due to several compensatory mechanisms that counteract the deforming forces. This may be a cause for the frequent complaint, early fatigue, and hence functional impairment. However, most radiological parameters did not correlate with muscle activities and larger study size may be required for further association.

LEVELS OF EVIDENCE

Diagnostic: Level 3.

Anatomical factors in the development of medial-sided osteochondral lesion of the talus: a comparative analysis

PURPOSE

The aim of this study was to determine anatomical predictors for the occurrence of medial osteochondral lesions of the talus (OLT), by analyzing morphometric variables obtained from magnetic resonance imaging (MRI).

METHODS

A total of 430 ankles with 215 ankle MRIs from patients with nontraumatic OLTs on the medial side of the talar dome and an equal number of age, sex, and side-matched healthy controls were analyzed in this retrospective study. The specific MRI parameters that were measured include the anterior opening angle of the talus (AOT), the angle between the tibial axis and medial malleolus (TMM), the angle of the tibial plafond to the malleoli (PMA), the angle between the anterior and posterior talofibular ligaments (ATFL-PTFL angle), length of the trochlea tali arc (TAL), sagittal length of distal tibial articular surface (TAS), the ratio of the sagittal length of distal tibial articular surface to the length of the trochlea tali arc (TAS/TAL), and the depth of the incisura fibularis (IncDep).

RESULTS

AOT, IncDep, ATFL-PTFL angle, PMA, TMM, TAL, and TAS/TAL exhibited significant differences between the two groups. The established cut-off values were 13° (AUC 0.875) for AOT, 3.7 mm (AUC 0.565) for IncDep, 78° (AUC 0.729) for ATFL-PTFL angle, 14° (AUC 0.581) for PMA, 15° (AUC 0.907) for TMM, 34.3 mm (AUC 0.599) for TAL, and 0.81 (AUC 0.719) for TAS/TAL. Multivariate logistic regression analysis revealed Odds Ratio (OR) = 22.22 for AOT > 13°, OR = 4.23 for ATFL-PTFL angle > 78°, OR = 1.99 for PMA ≤ 14°, OR = 31.598 for TMM > 15°, OR = 3.79 for TAS/TAL ≤ 0.81.

CONCLUSION

This study highlights the significance of anatomical parameters, particularly the TMM and AOT, as key predictors of OLT.

Determining the changes in morphology and loading status following medial displacement calcaneal osteotomy for flatfoot using patient-specific finite element models

Medial displacement calcaneal osteotomy (MDCO) is the standard procedure for flatfoot. We investigated the effect of MDCO on the foot using a finite element analysis. Foot models were created from computed tomography data of 8 patients with flat feet. MDCO was performed on each model with bone translation distance of 4, 8, and 12 mm. The morphological changes, plantar pressures, and stress percentage on the talocrural and subtalar joints were evaluated before and after surgery. Morphological evaluation showed improvement in the medial longitudinal arch. The stress percentage of plantar pressure in the medial area decreased, and the stress percentage of plantar pressure in the mid- and lateral forefoot area increased. At the talocrural joint, the medial and middle stress percentage increased, while the lateral and posterior stress percentage decreased. In the subtalar joint, the stress percentage in the middle subtalar joint increased and that in the posterior subtalar joint decreased. Within the posterior subtalar joint, the anterior and medial stress percentage increased, while the posterior and lateral stress percentage decreased. Preoperative simulation using the finite element analysis may be useful in understanding postoperative morphological changes and loading conditions to perform patient-specific surgery.

Joint preservation surgery for correcting adolescents' spasmodic flatfoot deformity: early results from a specialized North African foot and ankle unit

PURPOSE

We aimed to report early results of performing joint-preserving surgeries for managing spasmodic flatfoot deformity (SFFD) in adolescents.

METHODS

A prospective case series study including 24 patients (27 feet) diagnosed with idiopathic SFFD not responding to conservative management. After reassessment under anesthesia, surgical procedures included soft tissue releases (Achilles tendon (AT), peroneus brevis (PB), peroneus tertius (PT) (if present), and extensor digitorum longus (EDL)), bony osteotomies (lateral column lengthening (LCL), medial displacement calcaneal osteotomy (MDCO), and double calcaneal osteotomy (DCO)), and medial soft tissue reconstruction or augmentation if needed. Functional evaluation was performed per the American Orthopedic Foot and Ankle Society (AOFAS) score, while radiological parameters included talo-navicular coverage angle (TNCA), talo-first metatarsal angle (AP Meary's angle), calcaneal inclination angle (CIA), talo-calcaneal angle (TCA), talo-first metatarsal angle (Lat. Meary's angle), and tibio-calcaneal angle (TibCA). The preoperative parameters were compared to the last follow-up using the Wilcoxon signed test.

RESULTS

The mean age was 15.37 ± 3.4 years, 18 (75%) were boys, and the mean BMI was 28.52 ± 3.5 (kg/m2). Release of AT and fractional lengthening of PL, PT, and EDL were performed in all patients. LCL was needed in eight feet (29.6%), MDCO in 5 (18.5%), and DCO in 14 (51.9%). FDL transfer was required in 12 (44.4%) feet, and repair of the spring ligament in seven (25.9%). The mean operative time was 99.09 ± 15.67 min. All osteotomies were united after a mean of 2.3 ± 0.5 months. After a mean follow-up of 24.12 ± 8.88 months (12 and 36 months), the AOFAS improved from a preoperative mean of 43.89 ± 11.49 to a mean of 87.26 ± 9.92 (P < 0.001). All radiological parameters showed significant improvement, AP Meary's angle from a mean of 20.4 ± 5.3 to a mean of 9.2 ± 2.1, Lat. Meary's angle from - 15.67° ± 6.31 to - 5.63° ± 5.03, TNCA from - 26.48° ± 5.94 to 13.63° ± 4.36, CIA from 12.04° ± 2.63 to 16.11° ± 3.71, TibCA from - 14.04° ± 3.15 to - 9.37° ± 3.34, and TCA Lat. from 42.65° ± 10.68 to 25.60° ± 5.69 (P ≤ 0.001). One developed wound dehiscence (over an MDCO), managed with daily dressings and local antibiotics. Another one developed lateral foot pain after having LCL managed by metal removal.

CONCLUSION

Careful clinical and radiological evaluation for the correct diagnosis of SFFD is paramount. Joint-preserving bony osteotomies combined with selective soft tissue procedures resulted in acceptable functional and radiological outcomes in this young age group.

Oblique Dorsiflexion Osteotomy of the Distal Tibia for Fixed Ankle Equinus: Surgical Technique

Aim

There are significant challenges in the treatment of a severe rigid ankle equinus caused by a flat-topped talus, arthrogryposis, burn sequelae, or extensive scarring. Conventional approaches, such as soft tissue releases, often fail due to joint incongruence or compromised soft tissues, thereby necessitating supramalleolar osteotomies. The classic transverse supramalleolar osteotomy (TSO) of the distal tibia can lead to secondary anterior translation of the centre of rotation of the ankle and alters mechanical and anatomical axes. An alternative technique involves an oblique closing wedge osteotomy of the distal tibia, with a fulcrum near the ankle joint. This technical note delineates the planning parameters and procedural steps for the oblique dorsiflexion osteotomy of the distal tibia (ODODT).

Method

Using an anterior approach to the distal tibia, the "alpha angle," which determines the size of the closing wedge required for the foot to be plantigrade, is resected with a fulcrum at the most posterior part of the ankle joint, ensuring that the posterior cortex remains intact. The inclination of this resected wedge is planned preoperatively and is referred to as the "beta angle."  This aims to equalise the lengths on both sides of the osteotomy. For osteotomy fixation, 2 or 3 cannulated screws in lag mode are employed. Postoperatively, a short cast boot is used for 6 weeks.

Results

The ODODT is a salvage solution for severe rigid ankle equinus when first-line foot and ankle procedures are impractical due to tibiotalar incongruence or poor soft tissues. Advantages include minimal translation of the centre of rotation of the ankle, excellent stability when the posterior cortex remains intact, avoidance of large internal fixation devices, and cost-effectiveness, making it suitable for low-resource settings.

How to cite this article

Olleac R, Farfan F, Acosta L, et al. Oblique Dorsiflexion Osteotomy of the Distal Tibia for Fixed Ankle Equinus: Surgical Technique. Strategies Trauma Limb Reconstr 2024;19(2):104-110.

Frontal Plane Correction of Hallux Valgus Deformity With a Minimally Invasive Third Generation Tecnique: Short-Term Radiographic Outcomes of a Prospective Case Series

A number of minimally invasive osteotomies have been described for the repair of hallux abducto valgus (HAV) deformities. However, there are no known published studies that evaluate the effects of minimally invasive surgery techniques on the reduction of frontal plane rotation in patients with HAV. The purpose of this study was to assess correction in the transverse and frontal planes in patients undergoing surgical repair of HAV deformity utilizing a modified percutaneous technique. One hundred and five feet in 105 patients with HAV deformity were treated with a third generation minimally invasive technique using a first metatarsal osteotomy that allowed for frontal plane correction in conjunction with an Akin osteotomy. The minimum follow-up time was 12 months. Preoperative and postoperative anteroposterior weightbearing x-ray images were assessed and four measurements were evaluated: hallux abductus angle (HAA), intermetatarsal angle (IMA), tibial sesamoid position and frontal plane rotation of the first metatarsal. There were statistically significant differences for each of the assessments between the preoperative and postoperative radiographs (p < .001). There was a mean reduction in the HAA of 23.5° ± 9.6°, in the IMA, 7.0° ± 3.5°, in the tibial sesamoid position, 2.6 ± 1.3, and an improvement in the assessment of first metatarsal pronation (1.4 ± 0.9). The overall complication rate was 18.1%, with 5.7% of the feet requiring reoperation. The minimally invasive procedure employed by the authors demonstrated suitable outcomes in reducing deformity in both the transverse and frontal planes.

Torsional Deformity Significantly Impacts Lateral Ankle Radiographic Imaging Parameters

Background Optimal lateral ankle imaging is important for the diagnosis and treatment of multiple ankle conditions. The effects of limb deformity on lateral ankle imaging are not well described and are clarified in this osteological study. Materials and methods We utilized an osteological collection and imaged all specimens after the first positioning of the talus in the lateral position and positioning the tibia and fibula to match. We then measured the relative positions of the tibia and fibula and their widths to calculate standard ratios. All measurements were evaluated for reliability using intra-class correlation coefficients. Multiple regression analysis determined how patient characteristics, tibial torsion, and medial proximal tibial angle affected various lateral ankle imaging ratios. Results The intra-class correlation coefficient was excellent for all measurements. In the multiple regression analysis, all five imaging ratios had at least one statistically significant outcome. The anterior tibiofibular interval (ATFI)-tibial width (TW) ratio (ATFI:TW) had only one association with sex and had the lowest standard deviation. All other parameters had variation with tibial torsion and/or medial proximal tibia angle (MPTA). The mean ATFI was 1.06 ± 0.21 cm and 1.19 ± 0.23 cm for females and males, respectively. Conclusions Patient sex and tibial torsion impacted the fidelity of lateral imaging parameters. ATFI:TW may pose the greatest utility given its minimal association with deformity parameters and low standard deviation.

Midterm Donor Site Morbidity After Vascularized Free Fibula Flap Harvesting

BACKGROUND

Vascularized fibula grafts (VFGs) have become one of the most preferred grafts for the reconstruction of bone defects. However, despite the many advantages over other graft options, recipient and donor site morbidities are also common. Donor site morbidity has been reported at rates ranging from 5% to 67%. The aim of this study was to present a single-center series examining the clinical, functional, and radiologic aspects of donor site morbidity following VFG harvesting.

METHODS

The study included 69 patients who underwent biological reconstruction with VFG for bone tumors, avascular necrosis of the femoral head, or bone defects after trauma. Patients were evaluated functionally, clinically, and radiologically for donor site morbidity.

RESULTS

Donor site morbidity was observed in 33 of 69 patients (48%). The most complications were sensation deficits around the feet and ankles (20 of 69; 29%). Knee laxity was more common in patients who underwent osteoarticular fibular resection (P = .006).

CONCLUSION

We found VFG to be an effective method for the reconstruction of large bone defects, but associated with a relatively high rate of complications. Complications requiring surgical intervention were rare and the majority of patients did not have long-term functional limitations.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Can Anatomical Differences Contribute to the Etiology of Danis-Weber Type B Lateral Malleolus Fractures?

Introduction Lateral malleolus fractures are among the most common ankle fractures, but the anatomical factors that may predispose individuals to this specific type of fracture are not fully understood. This study aims to explore whether distinct anatomical characteristics of the ankle joint contribute to an increased susceptibility to lateral malleolar fractures. Methods A retrospective analysis was conducted on 73 patients diagnosed with isolated lateral malleolar fractures between 2020 and 2023. An array of radiologic parameters, including distal tibial articular surface (DTAS) angle, bimalleolar tilt (BMT), medial malleolar length (MML), lateral malleolar length (LML), medial malleolar relative length (MMRL), lateral malleolar relative length (LMRL), medial malleolar slip angle (MMSA), talocrural angle (TCA), anterior inclination of the tibia (AI), and fibular position (FP), were meticulously measured on anteroposterior and lateral ankle radiographs for each study participant. We also measured the same parameters in 126 individuals who had not experienced an ankle fracture for comparison. Results Statistically significant differences were observed between the fracture group and the control group for DTAS angle, BMT, MML, MMRL, LMRL, TCA, AI, and FP (p<.05). Conversely, LML and MMSA displayed no significant variations between the two groups (p=0.745 and p=0.623). Effect sizes were notably large for DTAS and TCA, medium for MMRL, BMT, and AI, and small for LMRL, MML, and FP. Conclusion Our findings indicate an increased risk of lateral malleolus fractures in individuals with a relatively longer medial malleolus, a valgus-oriented ankle, reduced anterior inclination of the tibia, and an anteriorly positioned fibula. Taking protective measures during risky activities in individuals with these differences may help to prevent fractures.

Müller-Weiss Disease: Midfoot Arthrodesis in Reduction vs Malreduction

BACKGROUND

Midfoot arthrodesis is regarded as the main surgical approach for treating Müller-Weiss disease (MWD). This study aimed to investigate the incidence of postoperative pain during MWD treatment through midfoot reduction or malreduction during arthrodesis and to explore the factors influencing postoperative pain in patients with MWD.

METHODS

A total of 67 patients with MWD were recruited and divided into two groups according to whether midfoot alignment was reduced: reduction group (n = 38) and malreduction group (n = 29). Demographic characteristics before the operation and at the last follow-up, as well as clinical and radiographic parameters, were compared between the two groups. Clinical parameters included the American Orthopaedic Foot & Ankle Society score and visual analog scale score, whereas radiographic parameters included the calcaneal pitch angle, lateral Meary's angle, talometatarsal-1 angle dorsoplantar (TMT1dp), talocalcaneal angle dorsoplantar (Kite angle), talonavicular coverage angle, and medial navicular pole extrusion. Postoperative complications and incidence of midfoot pain were evaluated at the last follow-up visit.

RESULTS

The reduction group exhibited better clinical and radiological parameters, including the TMT1dp and medial navicular pole extrusion, than the malreduction group at the last follow-up (all P < .05). However, the calcaneal pitch angle, lateral Meary's angle, Kite angle, and talonavicular coverage angle did not significantly differ between the two groups (all P > .05). The overall incidence of midfoot pain was 26.4%. The reduction group showed a lower incidence of medial pain than the malreduction group (15.7% vs. 40.0%, P < .05). Regression analysis revealed that midfoot abduction, represented by the TMT1dp, was a critical factor for midfoot arthrodesis failure and that medial navicular pole extrusion was not correlated with postoperative midfoot pain.

CONCLUSION

Midfoot reduction arthrodesis yields better clinical outcomes than malreduction arthrodesis. The TMT1dp, representing midfoot abduction, is a key factor for midfoot arthrodesis failure. The extruded medial navicular bone may not affect postoperative medial midfoot pain.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Comparison of the Usefulness of Computer-Assisted Three-Dimensional Analysis and Weight-Bearing Radiographs in Ankle Osteoarthritis

Background

To evaluate the degree of deformation in patients with ankle osteoarthritis (OA), it is essential to measure the three-dimensional (3D), in other words, stereoscopic alignment of the ankle, subtalar, and foot arches. Generally, measurement of radiological parameters use two-dimensional (2D) anteroposterior and lateral radiographs in a weight-bearing state; however, computer-aided 3D analysis (Disior) using weight-bearing cone-beam computed tomography (CBCT) has recently been introduced.

Methods

In this study, we compared the 2D human radiographic method with a stereoscopic image in patients with ankle arthritis. We enrolled 57 patients diagnosed with OA (28 left and 29 right) and obtained both standing radiographs and weight-bearing CBCT. Patients were divided by the Takakura stage. The interclass correlation coefficient (ICC) for each result was confirmed.

Results

On the ICC between 2D radiographs and 3D analysis, the tibiotalar surface angle and lateral talo-1st metatarsal angle showed a good ICC grade (> 0.6), while other parameters did not have significant ICC results. Three-dimension was superior to radiographs in terms of statistical significance.

Conclusions

We demonstrated that 2D and stereoscopic images are useful for the diagnosis of OA. Our study also confirmed that the radiographic features affected by ankle OA varied. However, according to the results, the typical radiography is not sufficient to diagnose and determine a treatment plan for ankle OA. Therefore, the method of using 3D images should be considered.

The Reliability of Common Radiographic Measurements Used to Describe Foot Deformities

Radiographic measurements are frequently used to classify deformity and determine treatment options. Correlation coefficients can be used to determine inter- and intrarater reliability. Reliability is a required feature of any measurement if the measurement is to provide valid information. We calculated correlation coefficients for standard radiographic measurements used to categorize foot deformities: this was done for 52 sets of radiographs assessed by 5 raters. We aimed for generalizability, and kept rater instructions to match what was originally published for each measurement of interest with schematic illustration. Overall, our results mostly showed a lack of inter-rater reliability (correlation coefficients <0.4), and strong intrarater reliability (correlation coefficients >0.6), for 12 forefoot and 12 rearfoot radiographic measurements that are commonly used. The results of this investigation bring into question the routine use of radiographic measurements to categorize deformity, select treatments, and measure surgical outcomes, between surgeons, because the validity of these measurements appears to be threatened by weak inter-rater reliability. In order for these measurements to be considered useful, it may be necessary for surgeons to more rigorously define and practice making standard radiographic measurements.

Intraoperative fluoroscopic protocol to avoid rotational malalignment after nailing of tibia shaft fractures: introduction of the 'C-Arm Rotational View (CARV)'

PURPOSE

Rotational malalignment (≥ 10°) is a frequent pitfall of intramedullary-nailing of tibial shaft fractures. This study aimed to develop an intraoperative fluoroscopy protocol, coined 'C-Arm Rotational View (CARV)', to significantly reduce the risk for rotational malalignment and to test its clinical feasibility.

METHODS

A cadaver and clinical feasibility study was conducted to develop the CARV-technique, that included a standardized intraoperative fluoroscopy sequence of predefined landmarks on the uninjured and injured leg in which the rotation of the C-arm was used to verify for rotational alignment. A mid-shaft tibia fracture was simulated in a cadaver and an unlocked intramedullary-nail was inserted. Random degrees of rotational malalignment were applied using a hand-held goniometer via reference wires at the fracture site. Ten surgeons, blinded for the applied rotation, performed rotational corrections according to (1) current clinical practice after single-leg and dual-leg draping, and (2) according to the CARV-protocol. The primary outcome measure was the accuracy of the corrections relative to neutral tibial alignment. The CARV-protocol was tested in a small clinical cohort.

RESULTS

In total, 180 rotational corrections were performed by 10 surgeons. Correction according to clinical practice using single-leg and dual-leg draping resulted in a median difference of, respectively, 10.0° (IQR 5.0°) and 10.0° (IQR 5.0°) relative to neutral alignment. Single-leg and dual-leg draping resulted in malalignment (≥10°) in, respectively, 67% and 58% of the corrections. Standardized correction using the CARV resulted in a median difference of 5.0° (IQR 5.0°) relative to neutral alignment, with only 12% categorized as malalignment (≥10°). The incidence of rotational malalignment after application of the CARV decreased from 67% and 58% to 12% (p =  <0.001). Both consultants and residents successfully applied the CARV-protocol. Finally, three clinical patients with a tibial shaft fracture were treated according to the CARV-protocol, resulting all in acceptable alignment (<10°) based on postoperative CT-measurements.

CONCLUSION

This study introduces an easy-to-use and clinically feasible standardized intraoperative fluoroscopy protocol coined 'C-arm rotational view (CARV)' to minimize the risk for rotational malalignment following intramedullary-nailing of tibial shaft fractures.

A Comparison of Imaging Outcomes From 2 Weightbearing CT Modalities

BACKGROUND

The use of weightbearing images to diagnose foot and ankle injuries continues to offer hope for improved insight into pathologies, but weightbearing CT imaging has been limited by availability. The ability to apply force to the lower limb in a horizontal bore CT system may offer an adaptation to currently available imaging systems that provides access to weightbearing images without the acquisition of additional expensive imaging space or equipment.

METHODS

In order to determine whether a horizontal CT system could produce the same results as a standing CT, 3 images of one foot from 10 subjects was obtained and standard measures were calculated. Each subject underwent a standing CT scan, a scan in a horizontal bore CT machine while the subject pressed against a pedal with spring resistance and a finally a scan with the foot placed on the pedal but without any pressure.

RESULTS

No statistically significant difference between the standing and pedal-based CTs resulted. Navicular height and Meary angle (axial) were statistically different from nonweightbearing for both standing and horizontal systems. The horizontal results were statistically different from nonweightbearing in IM angle, talocalcaneal angle, and talonavicular coverage. No differences from nonweightbearing were found for either system in talar tilt, talocrural angle, or the lateral Meary angle.

CONCLUSION

The results in this initial study of normal control subjects suggest that a pedal-based loading mechanism may adapt a horizontal-bore CT system for the acquisition of weightbearing images.

CLINICAL RELEVANCE

The ability to acquire a weightbearing CT from a horizontal bore CT machine can make these images more available.

Relationship Between Obesity and Medial Longitudinal Arch Bowing

BACKGROUND

There have been reports about the association between obesity and the medial longitudinal arch (MLA) of foot. The purpose of this study is to investigate the change of various parameters related to the MLA according to obesity classification severity by the World Health Organization using weightbearing computed tomography (WBCT).

METHODS

WBCT data of the noninvolved side of patients presenting with unilateral foot and ankle problems or healthy candidates from September 2014 to October 2022 were extracted from a single referral hospital. Forty-four cases in each of 5 obesity classes were selected sequentially. Two orthopaedic surgeons measured foot and ankle offset, forefoot arch angle (FAA), hindfoot moment arm, percentage of uncoverage of the middle facet of the subtalar joint, talonavicular angle (TNA), navicular-medial cuneiform angle, medial cuneiform-first metatarsal angle, talus-first metatarsal angle (TMT1A), first tarsometatarsal subluxation (TMT1S), talonavicular coverage angle, navicular floor distance (NFD), and NFD per height. Positive values indicate plantar collapse. Intra- and interobserver reliabilities were assessed using intraclass correlation coefficients. One-way analysis of variance tests were performed for parametric data with equal variances, and Welch's test for unequal variances. Kruskal-Wallis test was performed for nonparametric data. Post hoc analysis was performed for statistically significant parameters. Correlation analysis between body mass index (BMI) and 12 parameters were performed using Pearson test.

RESULTS

Intraobserver and interobserver reliability were excellent, except for TMT1S. The TNA and TMT1A showed a statistically significant difference. FAA (r = -0.2), TNA (r = 0.182), TMT1A (r = 0.296), and NFD (r = -0.173) showed a statistically significant correlation with BMI.

CONCLUSION

In nonsymptomatic feet, we found that the talonavicular joint, as measured by the TNA, to be influenced by obesity classification. Obesity and increased BMI was associated with a negative influence on the MLA.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Automatic anatomical foot and ankle coordinate toolbox

Accurate analysis of bone position and orientation in foot and ankle studies relies on anatomical coordinate systems (ACS). Reliable ACSs are necessary for many biomechanical and clinical studies, especially those including weightbearing computed tomography and biplane fluoroscopy. Existing ACS approaches suffer from limitations such as manual input, oversimplifications, or non-physiological methods. To address these shortcomings, we introduce the Automatic Anatomical Foot and Ankle Coordinate Toolbox (AAFACT), a MATLAB-based toolbox that automates the calculation of ACSs for the major fourteen foot and ankle bones. In this manuscript, we present the development and evaluation of AAFACT, aiming to provide a standardized coordinate system toolbox for foot and ankle studies. The AAFACT was evaluated using a dataset of fifty-six models from seven pathological groups: asymptomatic, osteoarthritis, pilon fracture, progressive collapsing foot deformity, clubfoot, Charcot Marie Tooth, and cavovarus. Three analyses were conducted to assess the reliability of AAFACT. Firstly, ACSs were compared between automatically and manually segmented bone models to assess consistency. Secondly, ACSs were compared between individual bones and group mean bones to assess within-population precision. Lastly, ACSs were compared between the overall mean bone and group mean bones to assess the overall accuracy of anatomical representation. Statistical analyses, including statistical shape modeling, were performed to evaluate the reliability, accuracy, and precision of AAFACT. The comparison between automatically and manually segmented bone models showed consistency between the calculated ACSs. Additionally, the comparison between individual bones and group mean bones, as well as the comparison between the overall mean bone and group mean bones, revealed accurate and precise ACSs calculations. The AAFACT offers a practical and reliable solution for foot and ankle studies in clinical and engineering settings. It accommodates various foot and ankle pathologies while accounting for bone morphology and orientation. The automated calculation of ACSs eliminates the limitations associated with manual input and non-physiological methods. The evaluation results demonstrate the robustness and consistency of AAFACT, making it a valuable tool for researchers and clinicians. The standardized coordinate system provided by AAFACT enhances comparability between studies and facilitates advancements in foot and ankle research.

Metatarsophalangeal and interphalangeal joint angle measurements on weight-bearing CT images

BACKGROUND

The aim of this study was to present and evaluate methods of measuring toe joint angels using joint-surface based and inertial axes approaches.

METHODS

Nine scans of one frozen human cadaveric foot were obtained using weight-bearing CT. Two observers independently segmented bones in the forefoot and measured metatarsalphalangeal joint (MTPJ) angles, proximal and distal interphalangeal joint (PIPJ and DIPJ) angles and interphalangeal angles of the hallux (IPJ) using 1) inertial axes, representing the long anatomical axes, of the bones and 2) axes determined using centroids of articular joint surfaces.

RESULTS

The standard deviations (SD) of the IPJ/PIPJ and DIPJ angles were lower using joint-surface based axes (between 1.5˚ and 4.1˚) than when the inertial axes method was used (between 3.3˚ and 16.4˚), for MTPJ the SD's were similar for both methods (between 0.5˚ and 2.6˚). For the IPJ/PIPJ and DIPJ angles, the width of the 95% CI and the range were also lower using the joint-surface axes method (95% CI: 2.0˚-4.1˚ vs 3.2˚-16.3˚; range: 3.1˚-7.4˚ vs 3.8˚-35.8˚). Intra-class correlation coefficients (ICC) representing inter- and intra-rater reliability were good to excellent regarding the MTPJ and IPJ/PIPJ angles in both techniques (between 0.85 and 0.99). For DIPJ angles, ICC's were good for the inertial axes method (0.78 and 0.79) and moderate for the joint-surface axes method (0.60 and 0.70).

CONCLUSION

The joint-surface axes method enables reliable and reproducible measurements of MTPJ, IPJ/PIPJ and DIPJ angles. For PIPJ and DIPJ angles this method is preferable over the use of inertial axes.

The Controversial Definition of Normal Toe Alignment

"Normal" and "abnormal" are frequently used in surgical planning and to evaluate surgical results of the forefoot. However, there is no objectifiable value of metatarsophalangeal angles (MTPAs) 2-5 in the dorsoplantar (DP) view with which to objectively evaluate lesser toe alignment. We aimed to determine which angles are considered to be "normal" by orthopedic surgeons and radiologists. Thirty anonymized radiographs of feet were submitted twice in randomized order to determine the respective MTPAs 2-5. After six weeks, the anonymized radiographs and photographs of the same feet without apparent affiliation were presented again. The terms "normal," "borderline normal," and "abnormal" were assigned by the observers. Viewers considered MTP-2 alignment from 0° to -20° to be normal, and below -30° abnormal; MTP-3, 0° to -15° to be normal and below -30° abnormal; MTP-4, 0° to -10° normal and below -20° abnormal. Between 5° valgus and 15° varus was the range of MTP-5 recognized as normal. High intra-observer but low interobserver reliability with overall low correlation of clinical and radiographic aspects was observed. The assessment of the terms "normal" or "abnormal" are subject to a high degree of variation. Therefore, these terms should be used cautiously.

Lateral column lengthening (LCL) using a rectangular shape graft for managing symptomatic flexible flatfoot showed acceptable early functional and radiological outcomes

PURPOSE

We aimed to report the results of performing lateral column lengthening (LCL) using a rectangular-shaped graft to correct the flat foot deformity.

METHODS

A total of 28 feet of 19 patients (10 males, 9 females) having an average age of 10 ± 3.2 years who were unresponsive to conservative management underwent flat foot deformity correction through LCL procedure supplemented with rectangular-shaped graft harvested from the fibula. Functional assessment was performed according to the American Orthopedic Foot and Ankle Society (AOFAS) scale. The radiographic assessment consisted of four parameters, Meary's angle in both anteroposterior (AP) and lateral (Lat.) views, calcaneal inclination angle (CIA), and calcaneocuboid angle (CCA).

RESULTS

After an average of 30.2 ± 8.1 months, the AOFAS improved significantly from 46.7 ± 10.2 preoperatively to 86.7 ± 9.5 at the last follow up (P < 0.05). All the osteotomies showed healing at an average of 10.3 ± 2.7 weeks. All the radiological parameters showed significant improvement at the last follow up compared to the preoperative measurements, CIA from 6.3 ± 2.8-19.3 ± 3.5, Lat. Meary's angle from 19.3 ± 4.9-5.8 ± 2.5, AP Meary's Angle from 19.3 ± 5.8-6.1 ± 3.1, and CCA from 23.9 ± 8.2-6.8 ± 4.5, (P < 0.05). No pain at the site of the fibular osteotomy was reported in any of the patients.

CONCLUSION

Lateral column lengthening using a rectangular graft effectively restores bony alignment with good radiological and clinical results, high patient satisfaction, and acceptable complications.

Definitions and Measurements of Hindfoot Alignment and Their Biomechanical and Clinical Implications

This article presents a critical review of the past and the current state of the art in defining and measuring hindfoot, ankle, and subtalar alignment. It describes the transition occurring at present from two-dimensional to three-dimensional (3D) alignment measurements, which accompany the emergence of new, functional, high-resolution imaging modalities such as the weight-bearing cone-beam computerized tomography (CT) imaging. To ease and enhance the transition and acceptability of 3D alignment measurements, new acceptable standards for different clinical application are highly desirable.

Clinical, Radiographic and Gait Parameters Associated with Medial Arch Pain in the Flexible Pediatric Flatfoot

Pain in the flexible flatfoot is a common complaint, if present it is important to find its exact location and causes Therefore, the study aimed to find differences between children with and without medial arch pain and relate them to the reduction of pain following surgical treatment. Children with idiopathic flexible flatfeet were retrospectively included in the study. All children underwent a clinical, radiographic, and gait examination. The feet were subdivided into 2 groups: asymptomatic and those with medial arch pain. Factors associated with medial arch pain were identified via t test. Significant radiological and gait parameters were correlated to the change in medial arch pain score following surgery. Included were 322 feet belonging to 177 children, with the mean age of 11.8 (SD = 2.2) years. The pain was perceived in 52% of the feet, of these, 74% in the medial arch. In the group with pain, 31 feet received a gait analysis following surgery. The radiological parameters, talus-1 and -2 metatarsal angles and the gait parameter, calcaneal lateral shift during walking showed a significant difference (p ≤ .004) between the no pain and pain groups and were associated (R² ≥0.14, p ≤ .04) with the reduction in pain following surgery. The increased talus-1 and -2 metatarsal angles and the calcaneal lateral shift may cause increased tension on the soft-tissues along the medial side of the foot and may produce pain. Therapies aiming at improving the medial arch pain should be directed to normalize the talus-1 or -2 metatarsal angles and the calcaneal lateral shift.