Medical Policy: 07.01.34 

Original Effective Date: December 2006 

Reviewed: July 2021 

Revised: July 2021 



This policy contains information which is clinical in nature. The policy is not medical advice. The information in this policy is used by Wellmark to make determinations whether medical treatment is covered under the terms of a Wellmark member's health benefit plan. Physicians and other health care providers are responsible for medical advice and treatment. If you have specific health care needs, you should consult an appropriate health care professional. If you would like to request an accessible version of this document, please contact customer service at 800-524-9242.


Benefit Application:

Benefit determinations are based on the applicable contract language in effect at the time the services were rendered. Exclusions, limitations or exceptions may apply. Benefits may vary based on contract, and individual member benefits must be verified. Wellmark determines medical necessity only if the benefit exists and no contract exclusions are applicable. This medical policy may not apply to FEP. Benefits are determined by the Federal Employee Program.


This Medical Policy document describes the status of medical technology at the time the document was developed. Since that time, new technology may have emerged or new medical literature may have been published. This Medical Policy will be reviewed regularly and be updated as scientific and medical literature becomes available.



This policy only applies to subtalar arthroereisis (sinus tarsi implant or stent) surgery.

  • Arthroereisis is a surgical procedure that limits movement across a joint. Subtalar arthroereisis also called extraosseous talotarsal stabilization is designed to correct excessive talar displacement and calcaneal eversion by reducing pronation across the subtalar joint.
  • The stabilization procedure is performed by placing an implant in the sinus tarsi, which is a canal located between the talus and the calcaneus.


Arthrodesis describes a surgical fusion of a joint so that the bones grow together. Subtalar arthrodesis (joint fusion) surgery is not addressed in this policy.


Clinically Valid

The technology must detect presence or absence of a condition (flat foot), the risk of developing a condition in the future or treatment response (beneficial or adverse).


Clinically Useful

A procedure is clinically useful if it improves the net health outcome of care. The net health outcome can be improved if patients receive correct therapy, or more effective therapy, or avoid unnecessary therapy, or avoid unnecessary testing.    


Flat Foot

Flatfoot (also known as pes planus) is often a complex disorder, with diverse symptoms and varying degrees of deformity and disability. Common characteristics of flat foot are a partial or total collapse of the arch.


Flexible flatfoot is a common disorder, anatomically described as excessive pronation during weight-bearing due to anterior and medial displacement of the talus. It may be congenital, or it may be acquired in adulthood due to posterior tibial tendon dysfunction, which in turn may be caused by trauma, overuse, inflammatory disorders, and other factors. Symptoms include dull, aching and throbbing, cramping pain, which in children may be described as growing pains. Additional symptoms include refusal to participate in athletics or walking long distances.


Conservative treatments include orthotics or shoe modifications, stretching exercises and medication. Various surgical techniques of subtalar arthroereisis have been used in the treatment of patients who have failed conservative treatment.


Arthroereisis is the limitation of excessive movement across the joint. Subtalar arthroereisis is designed to correct the excessive talar displacement and calcaneal eversion by placing an implant in the sinus tarsi, a canal located between the talus and the calcaneus. Subtalar arthroereisis has been performed for a number of years, with a variety of implant designs and compositions. The value of subtalar arthroereisis in the management and treatment of flatfoot deformity has not been established.



The relevant population of interest is individuals with flatfoot.



The therapy being considered is subtalar arthroereisis (also called extraosseous talotarsal stabilization).



Conservative treatments include over the counter (OTC) and prescription drug therapy, physical therapy, orthotics or shoe modifications. Surgical approaches for painful flatfoot deformities include tendon transfers, osteotomy, and arthrodesis.



The outcomes of interest are symptoms, functional outcomes, and quality of life. The average length of follow-up was 18 to 24 months.



Graham et al (2012) published a case series that was not confounded by adjunctive procedures and had a relatively long follow-up This study reported mean 51-month follow-up of talotarsal stabilization in 117 feet using the HyProCure device. Patients who received adjunctive procedures affecting the talotarsal joint were excluded from analysis. Adults who met the inclusion and exclusion criteria were invited to participate in the study. Eighty-three patients gave consent to participate, and 78 completed the Maryland Foot Score Questionnaire. Five patients did not complete the questionnaire because they had 7 (6%) implants removed. There were 16 revision surgeries with HyProCure. Nine of the surgeries called for the repositioning of a partially displaced device, or a change in the size of the device altogether. Of the patients who retained the device, 52% reported complete alleviation of foot pain, 69% had no limitations in their foot functional abilities, and 80% reported complete satisfaction with the appearance of their feet. This case series is notable for its assessment of functional outcomes at medium-term follow-up in patients who did not have adjunct procedures.


Metcalfe et al (2011) published a systematic review of the literature on subtalar arthroereisis for pediatric flexible flatfoot. Seventy-six case series (none controlled) or case reports were identified. Ten of the studies (756 feet) provided a clinician-based assessment of the surgical result graded from “excellent to poor” with follow-up between 36 and 240 months. Six studies (212 feet) included estimates of overall patient satisfaction using nonvalidated outcome measures, while 1 study (16 feet) found significant improvement using a validated foot-specific patient outcome measure. Data from 15 studies that reported radiographic values were combined for analysis. Although 8 of 9 radiographic parameters showed statistically significant improvements following arthroereisis procedures, the relation between radiographic and clinical outcomes is uncertain. The procedure was associated with several complications including sinus tarsi pain, device extrusion, and under correction. Complication rates ranged from 4.8% to 18.6%, with unplanned removal rates between 7.1% and 19.3% across all device types. The influence of adjunctive procedures on outcomes was not addressed in this review.


Summary of Evidence: Flat Foot

Currently, updated guidelines and randomized high-quality studies are lacking. There are no randomized, prospective controlled studies that evaluate the safety and efficacy of subtalar arthroereisis in combination with other surgical procedures.  Limitations of the published data is the lack of long-term outcomes, particularly important since the procedure is often performed in growing children, and the difficulty in separating the effect of this procedure from that of other adjunctive treatments. In addition, some publications report high rates of complications and implant removal. There is a lack of consistency with conservative treatments in the available literature where efficacy is shown with the subtalar arthroeisis procedure. Defining the true treatment population in the treatment of childhood and adult flatfoot lack a clear consensus.


Talotarsal Joint Dislocation

Talotarsal joint dislocation means that the joint surfaces of the talus are abnormally aligned on the heel and/or navicular bones. The purpose of subtalar arthroereisis in patients who have talotarsal joint dislocation is to provide a treatment option that is an alternative to or an improvement on existing therapies.



The relevant population of interest is individuals with talotarsal joint dislocation.



The therapy being considered is subtalar arthroereisis.



Alternative surgical approaches for talotarsal joint dislocation.



The outcomes of interest are symptoms, functional outcomes, and quality of life. The follow-up was up to one year.



Bresnahan et al (2013) reported on a prospective study of talotarsal stabilization using HyProCure in 46 feet of 35 patients diagnosed with recurrent and/or partial talotarsal joint dislocation. No procedures besides insertion of the HyProCure device were performed to address the talotarsal joint dislocation. At 1 year postoperatively, scores on the Maryland Foot Score (on a score out of 100) for 30 patients had improved from 69.53 preoperatively to 89.17 postoperatively. Foot pain decreased by 37.0%, foot functional activities improved by 14.4%, and foot appearance improved by 29.5%. Implants were removed from 2 feet with no unresolved complications.


Summary of Evidence: Talotarsal Joint Dislocation

Currently there are not published control trials comparing talotarsal stabilization with extra-osseous subtalar joint implant and nonsurgical treatment or alternative surgical techniques.  Although improvements in pain and function were observed, the current evidence on the use of subtalar arthroereisis for treatment of talotarsal joint dislocation is insufficient to determine that the technology results in an improvement in the net health outcome.


Practice Guidelines and Position Statements

(2009) National Institute for Clinical Excellence (NICE)

Guidance from the United Kingdom’s National Institute for Clinical Excellence concluded that current evidence on the safety and efficacy of sinus tarsi implant insertion for mobile flatfoot is inadequate in quality and quantity. Therefore, this procedure should only be used with special arrangements for clinical governance, consent and audit, or research.


(2020) American College of Foot and Ankle Surgeons (ACFAS)

The ACFAS published a consensus statement on the appropriate clinical management of adult-acquired flatfoot deformity (AAFD). The consensus statement stated that the following is neither appropriate nor inappropriate: subtalar arthroereisis should not be considered as a single corrective procedure for stage IIB AAFD. There is limited literature demonstrating the use of a subtalar implant alone to address pronation of the foot in type IIa deformity. The ACFAS also stated that the most identified complication is sinus tarsi pain due to presence of the implant; explanation resolves the pain.


(2004) American College of Foot and Ankle Surgeons (ACFAS)

The ACFAS guideline on pediatric flatfoot states: "proponents of this procedure (arthroereisis) argue that it is a minimally invasive technique that does not distort the normal anatomy of the foot. Others have expressed concern about placing a permanent foreign body into a mobile segment of a child’s foot. The indication for this procedure remains controversial in the surgical community."


Regulatory Status

Several implants have been cleared for marketing by the U.S. Food and Drug Administration (FDA) through the 510(k) process and are summarized/listed below. In general, these devices are indicated for insertion into the sinus tarsi of the foot, allowing normal subtalar joint motion while blocking excessive pronation.


Other subtalar implants include but are not limited to:

  • Arthrex Prostop and Arthrex Prostop Plus Subtalar Arthroeresis Implant
  • Bioarch Subtalar Arthroereisis Implant
  • BioBLOCK Resorbable Subtalar Implant
  • BioPro Horizon Subtalar Implant
  • Conical Subtalar Implant (CSI)
  • Disco Subtalar Implant
  • Futura Angled Subtalar Implant 
  • Futura Conical Subtalar Implant
  • HyProCure Subtalar Implant System
  • IFS Subtalar Implant
  • Kalix II
  • Life Spine Subtalar Implant System
  • Lundeen Subtalar Implant
  • Maxwell-Brancheau arthroereisis (MBA) Implant
  • MBA Resorb Implant
  • MetaSurg BioArch Subtalar Implant System
  • Nexa Orthopedics Subtalar Peg
  • Normed Vario Subtalar Screw
  • NuGait Subtalar Implant System
  • OsteoMed Talar-Fit Subtalar Implant System
  • OsteoSpring FootJack Subtalar Implant System
  • Smith Subtalar Arthroereisis Implant
  • SubFix Arthroeisis Implant
  • Sub-Talar Lok Arthroereisis Subtalar Implant System
  • Subtalar Maxwell-Brancheau Arthroereisis (MBA) Implant System
  • Talus of Vilex (TOV) Subtalar Implant
  • Trilliant Surgical Subtalar Implant
  • Twist Subtalar Implant.


Prior Approval:

Not applicable



Subtalar arthroereisis/extra-osseous subtalar joint implant is considered investigational for all indications.


The evidence is insufficient as the technology does not improve net health outcomes.


Procedure Codes and Billing Guidelines:

To report provider services, use appropriate CPT* codes, Modifiers, Alpha Numeric (HCPCS level 2) codes, Revenue codes, and/or diagnosis codes.

  • S2117 Arthroereisis, subtalar
  • 0335T Insertion of sinus tarsi implant
  • 0510T Removal of sinus tarsi implant
  • 0511T Removal and reinsertion of sinus tarsi implant
  • 28899 Unlisted procedure, foot or toes


Selected References:

  • Nelson SC, Haycock DM, Little ER. Flexible flatfoot treatment with arthroereisis: radiographic improvement and child health survey analysis. J Foot Ankle Surg. 2004;43(3):144-55. PubMed 15181430 [PMID].
  • Husain ZS, Fallat LM. Biomechanical analysis of Maxwell-Brancheau arthroereisis implants. J Foot ankle Surf. 2002 Nov-Dec;41(6):352-8.
  • Needleman RL. Current Topic Review: Subtalar Arthroereisis for the Correction of Flexible Flatfoot. Foot & Ankle Int. 2005 April;26(4):336-346.
  • Vora AN, Tien TR, Parks BG. Correction of moderate and severe acquired flexible flatfoot with medializing calcaneal osteotomy and flexor digitorum longus transfer. J Bone & Joint Sug. AM. 88:1726-1734, 2006.
  • Harris EJ, Vanore JV, Thomas JL, Kravitz SR, Mendelson SA, Mendicino RW, Silvani SH, Gassen SC; Clinical Practice Guideline Pediatric Flatfoot Panel. Diagnosis and treatment of pediatric flatfoot. J Foot Ankle Surg. 2004. Nov-Dec;43(6):341-73.
  • Lee MS, Vanore JV, Thomas JL, Catanzariti AR, Kogler G, Kravitz SR, Miller SJ, Gassen SC. Diagnosis and treatment of adult flatfoot. J Foot Ankle Surg 2005 Mar-Apr;44(2):78-113.
  • Needleman RL, A surgical approach for flexible flatfeet in adults including a subtalar arthroeresis with the MBA sinus tarsi implant. Foot Ankle Int. 2006 Jan;(1)9-18.
  • ECRI. Institute Subtalar Arthroereisis Implants for Treatment of Flexible Flatfoot Deformity. Plymouth Meeting (PA): ECRI Institute; 2006 Dec 28. 8p. [ECRI hotline response.
  • Saxena A, Nguyen A, Preliminary radiographic findings and sizing implications on patients undergoing bioabsorbable subtalar arthroeresis. J Foot Ankle Surg. 2007 May-June;46(3)175-80.
  • National Institute for Health and Clinical Excellence (NICE). Sinus tarsi implant insertion for mobile flatfoot. Interventional Procedure Guidance 305. July 2009.
  • ECRI. Subtalar Arthroereisis Implants for Treatment of Flexible Flatfoot. Plymouth Meeting (PA): ECRI Institute 2011 July 19. [Hotline Response].
  • Gross C, Erickson BJ, Adams SB, Parekh SG. Ankle arthrodesis after failed total ankle replacement: A systematic review of the literature. Foot Ankle Spec. 2015;8(2):143-151.
  • Chong DY, Macwilliams BA, Hennessey TA, et al. Prospective comparison of subtalar arthroereisis with lateral column lengthening for painful flatfeet. J Pediatr Orthop B. Jul 2015;24(4):345-353. PMID 25856275
  • Harris EJ, Vanore JV, Thomas JL, et al. Clinical Practice Guideline Pediatric Flatfoot Panel:American College of Foot and Ankle Surgeons (ACFAS). Diagnosis and treatment of pediatric flatfoot. J Foot Ankle Surg. Nov-Dec 2004;43(6):341-373. PMID 15605048
  • Lee MS, Vanore JV, Thomas JL, et al. Clinical Practice Guideline Adult Flatfoot Panel: American College of Foot and Ankle Surgeons (ACFAS). Diagnosis and treatment of adult flatfoot. J Foot Ankle Surg. Mar-Apr 2005;44(2):78-113. PMID 15768358
  • Sullivan MP, Firoozabadi R. Current management of talar fractures. Instr Course Lect. 2017;66:39-49.
  • Bernasconi, A., Lintz, F., Sadile, F. The role of arthroeisis of the subtalar joint for flatfoot in children and adults. EFFORT Open Rev 2017; 438-446. 
  • Walley KC, Greene G, Hallam J, et al. Short- to mid-term outcomes following the use of an arthroereisis implant as an adjunct for correction of flexible, acquired flatfoot deformity in adults. Foot Ankle Spec. 2018 Apr 1.
  • Caravaggi P, Lullini G, Berti L, et al. Functional evaluation of bilateral subtalar arthroereisis for the correction of flexible flatfoot in children: 1-year follow-up. Gait Posture. 2018;64:152-158. 
  • Indino C, Villafañe J, et. al. Effectiveness of subtalar arthroereisis with endorthesis for pediatric flexible flat foot: a retrospective cross-sectional study with final follow up at skeletal maturity. Foot Ankle Surg. 2018 Dec 21. pii: S1268-7731(18)30505-8. doi: 10.1016/j.fas.2018.12.002
  • Viladot Voegeli A, Fontecilla Cornejo N, Serrá Sandoval JA, Alvarez Goenaga F, Viladot Pericé R. Results of subtalar arthroereisis for posterior tibial tendon dysfunction stage IIA1. Based on 35 patients. Foot Ankle Surg. 2018 Feb;24(1):28-33. 
  • Metcalfe SA, Bowling FL, Reeves ND. Subtalar joint arthroereisis in the management of pediatric flexible flatfoot: a critical review of the literature. Foot Ankle Int. Dec 2011; 32(12): 1127-39. PMID 22381197
  • Graham ME, Jawrani NT, Chikka A. Extraosseous talotarsal stabilization using HyProCure(R) in adults: a 5-year retrospective follow-up. J Foot Ankle Surg. Jan-Feb 2012; 51(1): 23-9. PMID 22196455
  • Bresnahan PJ, Chariton JT, Vedpathak A. Extraosseous talotarsal stabilization using HyProCure(R): preliminary clinical outcomes of a prospective case series. J Foot Ankle Surg. Mar-Apr 2013; 52(2): 195-202. PMID 23313499
  • Piraino JA, Theodoulou MH, Ortiz J, et al. American College of Foot and Ankle Surgeons Clinical Consensus Statement: Appropriate Clinical Management of Adult-Acquired Flatfoot Deformity. J Foot Ankle Surg. 2020 Mar-Apr;59(2):347-355. doi: 10.1053/j.jfas.2019.09.001. PMID: 32131002.


Policy History:

  • July 2021 - Annual Review, Policy Revised
  • July 2020 - Annual Review, Policy Revised
  • July 2019 - Annual Review, Policy Revised
  • July 2018 - Annual Review, Policy Revised
  • July 2017 - Annual Review, Policy Revised
  • July 2016 - Annual Review, Policy Renewed
  • August 2015 - Annual Review, Policy Renewed
  • September 2014 - Annual Review, Policy Revised
  • October 2013 - Interim Review, Policy Revised
  • May 2013 - Annual Review, Policy Renewed
  • May 2012 - Annual Review, Policy Renewed
  • June 2011 - Annual Review, Policy Renewed

Wellmark medical policies address the complex issue of technology assessment of new and emerging treatments, devices, drugs, etc.   They are developed to assist in administering plan benefits and constitute neither offers of coverage nor medical advice. Wellmark medical policies contain only a partial, general description of plan or program benefits and do not constitute a contract. Wellmark does not provide health care services and, therefore, cannot guarantee any results or outcomes. Participating providers are independent contractors in private practice and are neither employees nor agents of Wellmark or its affiliates. Treating providers are solely responsible for medical advice and treatment of members. Our medical policies may be updated and therefore are subject to change without notice.


*CPT® is a registered trademark of the American Medical Association.