Long-Term Results of Subtalar Arthroereisis for Symptomatic Flexible Flatfoot in Pediatrics

doi:10.21203/rs.3.rs-5206489/v1

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Research Article

Long-Term Results of Subtalar Arthroereisis for Symptomatic Flexible Flatfoot in Pediatrics

https://doi.org/10.21203/rs.3.rs-5206489/v1

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Purpose:

Subtalar arthroereisis (STA) is a clinical intervention used for the correction of flexible flatfoot (FFF) in the pediatric population. This study aims to evaluate the radiographic, clinical, and patient-reported outcomes of STA for symptomatic FFF in pediatric patients with a minimum follow-up period of nine years.

Methods:

A cohort of 19 patients (38 feet) who underwent STA for FFF treatment between 2011 and 2015 was analyzed. This study featured a minimum follow-up period of nine years and involved comprehensive radiographic measurements. Clinical function assessment included footprint analysis classified using the Viladot classification, the Foot and Ankle Outcome Score (FAOS), and the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale. We calculated the association between preoperative and postoperative angles and functional results. Receiver operating characteristic (ROC) curve analyses were conducted to establish the optimal threshold to predict good clinical outcomes.

Results:

The average age at the time of surgery was 11 ± 1.79 years, and the mean duration of follow-up was 10 ± 1.4 years. After the surgical intervention, all foot angles showed statistically significant improvements. Normal foot alignment according to the Viladot classification was noted in 71% of patients. Good to excellent functional outcomes, as measured by both the AOFAS-hindfoot score and FAOS score, were reported in 84.2% of patients. Significant correlations were found between the preoperative and postoperative angles and functional results. Based on ROC curve analysis, the cut-off values were determined to be 28.5 degrees for the talonavicular coverage angle, 19.5 degrees for Meary’s angle, and 37.5 degrees for the talar declination angle.

Conclusion:

Our study indicates that STA is an effective procedure for durable deformity correction in pediatric patients with FFF. Restoring the medial longitudinal arch and correcting forefoot abduction are essential for improving functional outcomes. Both preoperative and postoperative angles were significantly associated with functional results, and the identified preoperative cut-off values are helpful for selecting surgical candidates.

Flexible flatfoot

Pediatrics

Subtalar arthroereisis

Talar-fit

Flexible flatfoot (FFF), also known as pes planus, is a common orthopedic condition in pediatric populations and is often asymptomatic.[1] Treatment is indicated for patients experiencing early fatigue, gait disturbance, and pain. Satisfactory outcomes for FFF can often be achieved using orthoses and Achilles tendon stretching exercises.[1, 2] Surgical intervention, including subtalar arthroereisis (STA), osteotomies, tendon lengthening, and transfer, is considered when conservative management fails to correct the deformity.[2]

STA, involving the insertion of an implant into the sinus tarsi, limits excessive eversion of the subtalar joint. Due to its minimal invasiveness, STA has been widely adopted clinically to correct the flatfoot deformity.[3–5] Previous literature has demonstrated advantages including three-dimensional correction, minimal invasiveness and rapid postoperative recovery.[6, 7] However, the evidence has been limited to short- to mid-term retrospective studies. Only one study reported satisfactory long-term results in 15-year follow-up in patients who underwent STA with a bioabsorbable implant.[8]

The goal of this study is to report the long-term radiographic and clinical outcomes of a series of patients who underwent STA with a nonabsorbable implant for symptomatic FFF.

Study design and patient selection

This is a single-center, retrospective cross-sectional investigation. Electronic medical records were reviewed after obtaining the approval of the institutional review board (IRB number 1110703). This study was conducted in compliance with the Health Insurance Portability and Accountability Act and the Declaration of Helsinki.[9]

Between 2011 and 2015, we identified 68 potential participants who had undergone STA for symptomatic FFF. We included patients whose age at the time of surgery was between 9 and 13 years old. Exclusion criteria encompassed patients with rigid flatfoot, sequelae of clubfoot, a history of prior lower limb trauma or surgery, neurogenic or neuromuscular disorders, generalized joint hyperlaxity, those who underwent associated procedures other than Achilles tendon lengthening or accessory navicular removal, and individuals with incomplete radiographic assessments.

A total of 50 patients were selected and contacted via phone, explaining the purpose of this additional examination and requesting participant consent. Ten patients were unreachable. Twenty patients were unavailable for a face-to-face clinic visit. Outpatient appointments for clinical and radiographic assessments were scheduled for the remaining twenty patients for both clinical and radiographic assessment. One patient was excluded from the study due to an underlying history of cerebral palsy.

Prosthesis

Two different implant designs were used in this study: the titanium alloy Talar-Fit (Osteomed, Addison, TX, USA) and the polyethylene disk and peg implant (STA-Peg, Wright Medical). The Talar-fit is a cone-shaped implant designed to adapt to the anatomical features of the sinus tarsi. It is cannulated to facilitate accurate implant positioning, with deep threaded patterns claimed to promote tissue ingrowth and enhance stability. The STA-Peg fits into the dorsal surface of the calcaneus just anterior to the posterior facet and is secured with a stem inserted into a prepared hole in the calcaneus. Both implants were designed to prevent excessive eversion of the talus, correct heel valgus, and increase the medial longitudinal arch.

Surgical techniques for Talar-fit

A skin incision was made 1 cm anterior and 1 cm inferior to the level of the lateral malleoli. Blunt dissection was performed to expose the tarsal sinus. A guide pin was inserted into the sinus tarsi and passed through the tarsal canal. Implant trials were inserted in a sequential sizing manner with the subtalar joint inverted. Once the appropriate size was determined, the implant trial was removed, and the appropriate implant was inserted. The implant position and range of motion (ROM) of the subtalar joint were confirmed using fluoroscopy. The wound was irrigated, closed in layers, and dressed appropriately with a compression dressing.

Surgical techniques for STA-peg

A curved skin incision was made over the sinus tarsi, followed by blunt dissection to expose the tarsal sinus. The foot was supinated to reveal the edge of the posterior articular facet of the calcaneus. A hole was then created just in front of the posterior facet of the calcaneus using the STA-Peg guide and drill. Sizers were employed to determine the appropriate implant size. Once the correct size was determined, a STA-Peg implant was cemented into position. The implant's position and the ROM of the subtalar joint were confirmed using fluoroscopy. The wound was irrigated, closed in layers, and dressed appropriately with a compression dressing.

Postoperative protocol

A short leg splint was applied to immobilize the ankle joint in a neutral position for all patients during the initial four weeks postoperatively. Gradual weight-bearing as tolerated was permitted immediately postoperatively. Patients received outpatient department (OPD) follow-up appointments at 2, 4, and 8 weeks after the operation.

Radiographic evaluation

Preoperative and immediate postoperative standard weight-bearing anteroposterior and lateral radiographs of the operated foot were retrieved from our digital database. Standard weight-bearing radiographs in both anteroposterior and lateral views were obtained during the last outpatient department (OPD) visit. The following measurements were taken on the anteroposterior view: talonavicular coverage angle, talar–1st metatarsal angle, Kite's angle(antero-posterior talocalcaneal angle) and fibular axis calcaneal offset (FACO), as shown in Figs. 1 and 2.. On the lateral view, we measured Meary's angle (lateral talar–1st metatarsal angle), calcaneal inclination, talar declination, talocalcaneal angle, and the Moreau-Costa-Bartani angle, as shown in Fig. 3. [3] All the measurement details are described in Table 1.

Table 1

Description of radiological measurements relevant to pes planus
Measurement	Descripition
Measure from a weight-bearing antero-posterior (AP) foot radiograph.
Talonavicular coverage angle	The angle formed between a line connecting the edges of the articular surface of the talus and the articular surface of the navicular
Antero-posterior talar–1st metatarsal angle	The angle formed from a line through the mid-axis of the talus and the long axis of the 1st metatarsal
Antero-posterior talocalcaneal angle (Kite’s angle)	The angle formed by a line bisecting the head and neck of the talus and a line along the lateral border of the calcaneus
Measure from a weight-bearing antero-posterior (AP) ankle mortise radiograph.
fibular axis calcaneal offset (FACO)	The widest horizontal distance between the mid-fibular axis and the calcaneal wall just inferior to the peroneal tubercle.
Measure from a weight-bearing lateral foot radiograph.
Lateral talar–1st metatarsal angle (Meary’s angle)	The angle formed from the bisection of the long axis of the talus and the 1st metatarsal
Calcaneal inclination	The angle formed between a line from the plantar surface of the calcaneus to the inferior distal articular surface and the transverse plan
Lateral talocalcaneal angle	The angle formed between a line bisecting the talus and a line from the plantar surface of the calcaneus to the inferior distal articular surface
Moreau-Costa-Bartani angle	The angle formed between a line from the inferior posterior calcaneal tuberosity to the inferior border of the talonavicular joint and a line from the medial sesamoid to the inferior border of the talonavicular joint
Talar declination	The angle formed between a line drawn along the long axis of the talus and the transverse plane

Functional evaluation and patient-reported outcomes

The degree of plantar collapse was classified according to the Viladot’s classification (grades 0 to 4) using podoscope.[10, 11] Functional outcomes were evaluated using the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot scale during the last OPD visit.[12] The AOFAS scale comprises three aspects: pain, function, and alignment, with a maximum score of 100 points. Scores of 85–100 are considered excellent, 75–84 as good, 65–74 as fair, and less than 65 as poor.

Patient-reported outcomes were documented using the Foot and Ankle Outcome Score (FAOS) during the last OPD visit.[13, 14] The FAOS score has a maximum of 100 points and results were categorized as 'excellent' (100 − 90), 'good' (89 − 80), 'fair' (79 − 70), and 'poor' (< 70).

Statistical Analysis

We presented the results of radiographic angles, AOFAS ankle-hindfoot scale, and FAOS as mean values and standard deviations (SD). Preoperative and postoperative radiographic angles were compared using the paired Student's t-test. Additionally, subgroup analysis was performed to compare results between males and females, considering both radiographic and functional outcomes.

To assess the influence of various variables on long-term functional outcomes, including age at the initial surgery, preoperative radiographic measurements, postoperative radiographic measurements, and the angle change between postoperative and preoperative measurements, we calculated and analyzed Pearson correlation coefficients.

Receiver operating characteristic (ROC) curves for the talonavicular coverage angle, Meary's angle, and talar declination angle were obtained to find the optimal cutoff value for good clinical outcomes, with an AOFAS score higher than 85 points and an FAOS score higher than 80 points. The area under the ROC curve (AUC) was computed for each angle. The optimal cutoff point was determined using the Youden index, defined as (sensitivity + specificity − 1).[15] By utilizing the cutoff points determined from assessing the ROC curves, the positive and negative predictive values of the diagnostic tests were calculated.

Data analysis was performed using SPSS 23.0 (IBM, Armonk, NY, USA), and a p-value of < 0.05 was considered statistically significant.

General demographics

A total of 68 potential participants were initially identified. Four patients were excluded due to incomplete medical records, and eight patients were excluded because they were older than 13 years of age. Among the remaining participants, 25 (45%) were female, and 31 (55%) were male. The mean age at the time of surgery was 11.3 years (range, 9–13 years). Bilateral feet were affected in 52 (92%) patients, while 45 (80%) patients underwent STA with Talar-Fit implantation, and 11 (20%) patients underwent STA with STA-Peg implantation. Four feet required implant removal due to irritation, and another four feet required implant removal because of implant dislodgement.

Among the 19 patients (38 feet) included in our study, 10 (52%) were female, and 9 (48%) were male. The mean age at the time of surgery was 11 years old (range, 9–13 years). All patients underwent bilateral STA, with 16 (84%) undergoing STA with Talar-Fit implantation and 3 (16%) undergoing STA with STA-Peg implantation. The mean follow-up time was 10 years (range, 9–13 years). Additionally, all patients underwent STA alone without adjunctive procedures.

Radiographic outcomes

Comparison of radiographic outcomes on standard weight-bearing anteroposterior radiographs revealed significant decreases in the talonavicular coverage angle (mean decrease of 16, p < 0.001), talar–1st metatarsal angle (mean decrease of 9.6, p < 0.001), and talar–1st metatarsal angle (mean decrease of 8.6, p < 0.001).

On standard weight-bearing lateral radiographs, there were significant decreases in the talar–1st metatarsal angle (mean decrease of 10.0, p < 0.001), talar declination (mean decrease of 7.6, p < 0.001), lateral talocalcaneal angle (mean decrease of 4.1, p < 0.001), Moreau-Costa-Bartani angle (mean decrease of 12.9, p < 0.001) and FACO (mean decrease 3.1, p < 0.001). Calcaneal inclination increased significantly by 3.7 degrees (p < 0.001).

Functional and patient-reported outcomes

According to Viladot classification, 27 feet were classified as normal, nine feet as grade I and two feet as grade II. At the final follow-up, the mean AOFAS score was 88.6 (range: 54–100). Fifteen patients were graded as excellent, one patient as good, two patients as fair, and one as poor. The mean FAOS score at the final follow-up was 91.3 (range: 72–100). Twelve patients were graded as excellent, four patients as good, and three patients as fair.

Subgroup analysis

When comparing the male and female groups, no significant differences were observed in the angle changes between postoperative and preoperative measurements. The AOFAS score (Male: 94.2, Female: 83.7, p = 0.06) and FAOS score (Male: 94.8, Female: 87.7, p = 0.08) were slightly higher in the male patient group, but these differences were not statistically significant.

Correlation analysis

The correlations between the listed variables and functional results are summarized in Table 2. Age exhibited no significant correlation with either the AOFAS score or FAOS score.

Table 2

Odds ratios for prediction of AOFAS score or FAOS score by univariate logistic regression
Preoperative
		Talonavicular coverage angle	Antero-posterior talar–1st metatarsal angle	Antero-posterior talocalcaneal angle	FACO	Meary’s angle	Talar declination	Calcaneal inclination	Lateral talocalcaneal angle	Moreau-Costa-Bartani angle
AOFAS	Odds ratio	-0.6954	0.1478	-0.394	0.08212	-0.6506	-0.4026	0.3534	-0.3799	-0.1645
AOFAS	p value	< 0.01	0.2615	0.02	0.6662	< 0.01	0.01	0.03	0.02	0.33
FAOS	Odds ratio	-0.4986	-0.2462	0.003101	0.05539	-0.4865	-0.4402	0.2606	-0.4446	0.0302
FAOS	p value	< 0.01	0.1478	-0.4672	0.7713	< 0.01	< 0.01	0.1248	< 0.01	0.8612
Postoperative
AOFAS	Odds ratio	-0.6478	0.1045	-0.295	0.05355	-0.5112	-0.4918	-0.09368	-0.3054	-0.1362
AOFAS	p value	< 0.01	0.5324	0.07214	0.7495	< 0.01	< 0.01	0.5759	0.06226	0.4148
FAOS	Odds ratio	-0.5042	0.009472	-0.468	-0.06207	-0.5782	-0.6324	-0.05581	-0.3641	-0.1691
FAOS	p value	< 0.01	0.955	< 0.01	0.7112	< 0.01	< 0.01	0.7393	0.02	0.3101
AOFAS, American Orthopedic Foot and Ankle Score; FAOS, Foot and Ankle Outcome Score; FACO, fibular axis calcaneal offset

Regarding preoperative radiographic measurements, several key correlations were observed with the AOFAS score and FAOS score. Notably, the talonavicular coverage angle (r = -0.70, p < 0.01), antero-posterior talocalcaneal angle (r = -0.39, p = 0.01), lateral talar–1st metatarsal angle (r = -0.65, p < 0.01), talar declination angle (r = -0.40, p = 0.01), calcaneal inclination (r = 0.35, p = 0.03), and lateral talocalcaneal angle (r = 0.38, p = 0.02) exhibited significant correlations with the AOFAS score. Similarly, for the FAOS score, significant correlations were identified with the talonavicular coverage angle (r = -0.50, p < 0.01), lateral talar–1st metatarsal angle (r = -0.48, p < 0.01), talar declination angle (r = -0.44, p < 0.01), and lateral talocalcaneal angle (r = -0.44, p < 0.01).

When considering postoperative radiographic measurements, significant correlations with the AOFAS score were observed for the talonavicular coverage angle (r = -0.65, p < 0.01), lateral talar–1st metatarsal angle (r = -0.51, p < 0.01), and talar declination (r = -0.49, p < 0.01). For the FAOS score, the talonavicular coverage angle (r = -0.50, p < 0.01), antero-posterior talocalcaneal angle (r = -0.47, p < 0.01), lateral talar–1st metatarsal angle (r = -0.57, p < 0.01), talar declination (r = -0.63, p < 0.01) and lateral talocalcaneal angle (r = -0.36, p = 0.02) exhibited significant correlations.

Regarding the angle change between postoperative and preoperative measurements, the lateral talar–1st metatarsal angle change (r = -0.44, p < 0.01) and calcaneal inclination change (r = 0.37, p = 0.02) were correlated with the AOFAS score. Interestingly, no significant correlation was found between angle change and the FAOS score.

ROC curve

The data presented in Table 3, derived from the ROC curves, distinguishes between "Excellent" and "inferior outcomes" in AOFAS scores, as well as between "Good to Excellent" and "inferior outcomes" in FAOS scores. Notably, the cutoff values for talonavicular coverage, Meary’s angle, and talar declination on the ROC curve remained consistent at 28.5 degrees, 19.5 degrees, and 37.5 degrees, respectively, across both AOFAS and FAOS scores.

Table 3

Cut-off values for the talonavicular coverage angle, Meary's angle, and talar declination angle, calculated from the ROC curve.
	Cut-off value	AOFAS score	FAOS score
Talonavicular coverage angle	28.5 degrees	AUC: 0.74 Sensitivity: 55% Specificity: 92.5%	AUC: 0.9 Sensitivity: 83.3% Specificity: 90%
Meary’s angle	19.5 degrees	AUC: 0.69 Sensitivity: 50% Specificity: 88.5%	AUC: 0.93 Sensitivity: 83.3% Specificity: 83.3%
Talar declination	37.5 degrees	AUC: 0.69 Sensitivity: 50% Specificity: 82.15%	AUC: 0.77 Sensitivity: 67% Specificity: 82.8%
AOFAS, American Orthopedic Foot and Ankle Score; FAOS, Foot and Ankle Outcome Score; AUC, area under the receiver operating characteristic curve

In terms of AOFAS score, the AUCs were 0.74 (95% CI: 0.63–0.85) for talonavicular coverage, 0.70 (95% CI: 0.56–0.84) for Meary’s angle, and 0.70 (95% CI: 0.61–0.79) for talar declination angle. For the FAOS score, the AUCs were 0.90 (95% CI: 0.86–0.94) for talonavicular coverage, 0.93 (95% CI: 0.89–0.97) for Meary’s angle, and 0.77 (95% CI: 0.68–0.86) for talar declination angle.

Complications

At final follow-up, three patients complained of the presence of pain in the sinus tarsi. However, none of these patients request implant removal.

The treatment of FFF in the pediatric population using STA remains controversial due to the limited availability of long-term studies investigating outcomes and complications.[3, 4, 16] Therefore, the goal of this study was to present the long-term results of using non-absorbable endo-orthosis for the treatment of FFF in the pediatric population. Our study demonstrates the effectiveness of STA in deformity correction radiographically and the overall improvement in functional performance, as documented through AOFAS and FAOS scores. Additionally, we conducted an analysis to identify potential predictors associated with improved functional outcomes and to establish safe thresholds for performing STA to ensure favorable outcomes.

All radiographic parameters measured in this study showed significant improvement following STA treatment. Many previous studies have demonstrated the effectiveness of radiologic correction after STA in short-term and mid-term follow-ups.[17–20] Indino et al. conducted a retrospective cross-sectional study with a final follow-up at skeletal maturity, enrolling a total of 56 consecutive patients (112 feet). Standard weight-bearing radiographs were used to measure various parameters such as the anteroposterior talonavicular angle, talonavicular uncoverage percent, lateral talocalcaneal angle, calcaneal pitch angle, and Meary’s angle. Their study showed that deformity correction after STA can be maintained even after skeletal maturity.[17] Another retrospective cross-sectional investigation, carried out by Mazzotti et al., focused on the long-term results of patients who underwent STA using bioabsorbable polymeric endo-orthotic implants for the treatment of symptomatic FFF. With an average follow-up of 15 years, they observed significant improvements in all radiographic parameters at the final follow-up.[8] Our study aligns with these findings, indicating that the effects of deformity correction following STA can be sustained over the long term.

The Viladot classification, known for its excellent intra- and interobserver agreement, is widely used to objectively interpret and classify the severity of medial longitudinal arch collapse in clinical practice.[21] Mazzotti et al. found that, in the long-term results, 73.4% of patients had a physiologic footprint (Viladot grade 0), and 20.3% were classified as Viladot grade I at the final follow-up.[8] These results indicate a significant improvement in the medial longitudinal arch, with the majority of patients maintaining a near-normal footprint. Our study yielded similar findings, with footprint assessment showing that 71% of patients achieved a physiologic footprint (Viladot grade 0), while 23% were classified as Viladot grade I at the final follow-up. These results demonstrate the long-term effectiveness of STA in restoring and maintaining the medial longitudinal arch in pediatric patients with FFF.

With respect to clinical outcomes, 84% of our patients reported good to excellent performance in both AOFAS and FAOS scores. This finding aligns with a systematic review and meta-analysis by Tan et al., where 88% of patients reported good to excellent performance in their postoperative outcomes.[6] Similarly, Mazzotti's study revealed that 88.2% of patients expressed satisfaction with the procedure and would choose to undergo STA again in the absence of fatigue, pain, or discomfort.[8] These findings highlighted that a significant majority of patients experienced substantial improvements in pain levels and functional capabilities postoperatively. Interestingly, we found that lower preoperative and postoperative talonavicular coverage angles, Meary’s angle, and talar declination angles were significantly associated with better functional outcomes.

Previous research by Prachgosin et al. focused on the biomechanics of the medial longitudinal arch (MLA), comparing normal feet with untreated flat feet.[22] The MLA deformation angle (MLAD), which indicates the flexibility of the MLA, is one of the key indicators for evaluating windlass mechanism function. MLAD was found to be significantly smaller in the flatfoot group. Additionally, they observed significantly greater eversion deforming forces and abnormal ground reaction forces during gait cycles in the flatfoot group, reflecting functional deficits. When treating flexible flatfoot deformities, surgeons aim to correct the medial arch collapse, hindfoot valgus, and forefoot abduction. Our findings suggest that lower preoperative talonavicular coverage angles, Meary’s angle, and talar declination angles are significantly associated with better functional outcomes. Therefore, establishing thresholds for these angles in preoperative assessments is imperative to ensure better outcomes during consultations.

Based on ROC curve analysis, the cut-off values were determined to be 28.5 degrees for the talonavicular coverage angle, 19.5 degrees for Meary’s angle, and 37.5 degrees for the talar declination angle. These threshold levels can assist surgeons in evaluating whether STA is a suitable surgical option and in setting numerical expectations for patients. However, values beyond these thresholds do not provide additional guidance for surgical decisions.

We must acknowledge several limitations in our study. Firstly, our data were collected retrospectively from a single institution, which may introduce potential selection bias and limit the generalizability of our findings due to the small sample size. Secondly, we did not include a comparison of STA with other treatment modalities, such as osteotomies or tendon transfers, which may limit the broader context of our results. Additionally, other significant factors, such as the type, size, and material of the implant, were not considered in our analysis. Therefore, it is prudent to interpret our findings with caution. To further validate our results, larger, high-quality, prospective, and randomized studies are needed.

In conclusion, our findings suggest that STA may be a valid option for providing durable deformity correction and improving functional performance in the treatment of FFF in pediatric patients. Both preoperative and postoperative angles were highly predictive of functional outcomes, and the reported preoperative cut-off values offer valuable prognostic information for selecting surgical candidates. Restoration of the medial longitudinal arch and correction of forefoot abduction appear to be crucial aspects of deformity correction, potentially contributing significantly to improved functional outcomes.

Funding: This study was not funded.

Consent for publication: Not applicable

Ethics approval: This study was performed in line with the principles of the Declaration of Helsinki and was approved by the Institutional Review Board. (IRB number 1110703)

Consent to participate: The informed consent was obtained from all subjects.

Author Contribution

JHW and YYC contribute to conceptualization and methodology. JHW and HCC perform formal analysis and investigation. JHW was a major contributor in writing the manuscript. Writing - review and editing was done by CHC, and YYC. All authors read and approved the final manuscript.

Acknowledgement

We thank Ms. Qian-Yi Huang and Chiu-Ching Chiang(Department of Orthopedic Surgery, Show Chwan Memorial Hospital, Changhua, Taiwan) for their assistance with this project.

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Wang S, Chen L, Yu J, Zhang C, Huang JZ, Wang X, Ma X (2021) Mid-term Results of Subtalar Arthroereisis with Talar-Fit Implant in Pediatric Flexible Flatfoot and Identifying the Effects of Adjunctive Procedures and Risk Factors for Sinus Tarsi Pain. Orthop Surg 13:175-184. DOI 10.1111/os.12864
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No competing interests reported.

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Long-Term Results of Subtalar Arthroereisis for Symptomatic Flexible Flatfoot in Pediatrics

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Version 1

Abstract

Purpose:

Methods:

Results:

Conclusion:

Figures

Introduction

Material and methods

Study design and patient selection

Prosthesis

Surgical techniques for Talar-fit

Surgical techniques for STA-peg

Postoperative protocol

Radiographic evaluation

Functional evaluation and patient-reported outcomes

Statistical Analysis

Results

General demographics

Radiographic outcomes

Functional and patient-reported outcomes

Subgroup analysis

Correlation analysis

ROC curve

Complications

Discussion

Declarations

Author Contribution

Acknowledgement

References

Additional Declarations

Status:

Version 1