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MP 7.01.104

Subtalar Arthroereisis

Medical Policy    
Original Policy Date
Last Review Status/Date
Reviewed with literature search/9:2014
  Return to Medical Policy Index


Our medical policies are designed for informational purposes only and are not an authorization, or an explanation of benefits, or a contract.  Receipt of benefits is subject to satisfaction of all terms and conditions of the coverage.  Medical technology is constantly changing, and we reserve the right to review and update our policies periodically. 


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 in nature 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. Surgical approaches for painful flatfoot deformities include tendon transfers, osteotomy, and arthrodesis. Arthroereisis with a variety of implant designs has also been investigated. Arthroereisis (also referred to as arthroisis) is the limitation of movement across a joint. STA or EOTTS is designed to correct excessive talar displacement and calcaneal eversion by reducing pronation across the subtalar joint. Extraosseous talotarsal stabilization is also being evaluated as a treatment of talotarsal joint dislocation. It is performed by placing an implant in the sinus tarsi, which is a canal located between the talus and the calcaneus.

STA has been performed for more than 50 years, with a variety of implant designs and compositions. The Maxwell-Brancheau Arthroereisis (MBA) implant is the most frequently reported, although other devices such as the HyProCure, STA peg, and Kalix are also described in the medical literature. The MBA implant is described as reversible and easy to insert, with the additional advantage that it does not require bone
cement. In children, insertion of the  MBA implant may be offered as a standalone procedure, although children and adults often require adjunctive surgical procedures on bone and soft tissue to correct additional deformities.

Regulatory Status

A number of implants have received marketing clearance through the U.S. Food and Drug Administration’s (FDA) 510(k) pathway. For example, the HyProCure® Subtalar Implant System/Extra Osseos Fixation Device (GraMedica) received marketing clearance in 2004 (K042030), the SubFix™ arthroereisis implant (Memometal Technologies, Bruz, France) received FDA marketing clearance in 2010 (K093820) and the Arthrex ProStop Plus™ (Arthrex, Naples, FL) received marketing clearance in 2008 (K071456). The MBA® implant (now owned by Integra LifeSciences Corp., Plainsboro, NJ) received 510(k) marketing clearance in 1996 (K960692) because it was substantially equivalent to products on the market prior to device regulation. According to the FDA summary, the primary indication for the Subtalar MBA device is “as a spacer for stabilization of the subtalar joint. It is designed to block the anterior and inferior displacement of the talus, thus allowing normal subtalar joint motion but blocking excessive pronation and the resulting sequela.” (1) The MBAResorb Implant received 510(k) marketing clearance in 2005 (K051611). This implant employs the same basic mechanical features as the predicate MBA implant but is composed of a material (poly l-lactic acid) that is resorbed by the body. Predicate devices include the Osteomed Talar-Fit™ (K031155), Nexa Orthopedics Subtalar Peg (K032902 and K033046), Arthroereisis Implant Talus of Vilex (TOV, K041289), Instrateck (K080280), and Wright Medical Smith Sta-Peg (K792670).  FDA product code: HWC


Subtalar arthroereisis is considered investigational.

Policy Guidelines

There is no specific CPT code for this procedure. It is possible that physicians may be using any of the following codes to describe subtalar arthroereisis:

28899: Unlisted procedure, foot or toes

28725: Arthrodesis; subtalar.
(Arthrodesis describes joint fusion)

28735: Arthrodesis, midtarsal or tarsometatarsal, multiple or transverse; with osteotomy (e.g., flatfoot correction)

28740: Arthrodesis, midtarsal or tarsometatarsal, single joint

29907: Arthroscopy, subtalar joint, surgical; with subtalar arthrodesis

On October 1, 2005, the following HCPCS S code became available:

S2117: Arthroereisis, subtalar

Effective January 1, 2014, there is a category III code for insertion of the HyProCure® device –

0335T: Extra-osseous subtalar joint implant for talotarsal stabilization.

Benefit Application
Blue Card/National Account Issues

State or federal mandates (e.g., the FEP) may dictate that all FDA-approved devices may not be considered investigational and thus these devices may be assessed only on the basis of their medical necessity.


Periodic literature searches of the MEDLINE database on subtalar arthroereisis (STA) have identified minimal published studies, primarily consisting of single institution case series and individual case reports. The most recent literature review, using the MEDLINE database, was performed through July 25, 2014. Following is a summary of the key literature to date.  

There are no controlled trials of STA compared with alternative treatments. The evidence base consists entirely of single-arm case series that report on success rates following this procedure. Interpretation of the current case series evidence is limited by the use of adjunctive procedures in addition to STA, creating difficulties in determining the extent to which each modality contributed to the outcomes. The evidence base is also limited by the lack of long-term follow-up, which may be particularly important for a procedure performed in children.


In 2011, Metcalfe et al published a systematic review of the literature on STA for pediatric flexible flatfoot.(2) Seventy-six case series or case reports (no controlled trials) were identified. Ten of the studies (756 feet) provided 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 relationship between radiographic and clinical outcomes is uncertain. The procedure was associated with a number of complications including sinus tarsi pain, device extrusion, and undercorrection. 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.

One case series that was not confounded by adjunctive procedures and that had a relatively long followup was published by Graham et al in 2012. This study reported mean 51-month follow-up of talotarsal stabilization in 117 feet using the HyProCure device.(3) Patients who received adjunctive procedures affecting the talotarsal joint were excluded from the analysis. Adult patients who met the inclusion/exclusion criteria were invited to participate in the study. Eighty-three patients gave consent to
participate, and 78 completed the Maryland Foot Score Questionnaire; 5 patients who had 7 implants (6%) removed did not complete the questionnaire. There were 16 revision surgeries with HyProCure; 9 involved repositioning of a partially displaced device or a change in size of the device. 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.

Other case series generally did not exclude the use of other adjunctive treatments. For example, in 1998 Vedantam et al reported on a series of 78 children (140 feet) with neuromuscular disease who underwent STA with an STA-peg.(4) The stem of this implant is placed into the calcaneous with the collar abutting the inferior surface of the lateral aspect of the talus, thus limiting motion. All but 5 of the children had additional procedures to balance the foot. Satisfactory results were reported in 96.4% of patients, although the contribution of the STA-peg cannot be isolated. In 2004, Nelson et al reported on 37 patients (67 feet) who underwent Maxwell-Brancheau Arthroereisis (MBA) implant with an average of 18.4 months of follow-up.(5) While this study reported various improvements in anatomic measurements, there were no
data on improvement in symptoms. Another series from 2006 reported significant improvements in pain and function in 78% of patients (23 patients, 28 feet) with use of a subtalar implant as a component of reconstructive foot and ankle surgery.(6) However, because results were not compared with controls receiving reconstructive surgery without STA, the contribution of the implants to these outcomes is unclear. In addition, the authors reported an overall complication rate of 46%, with surgical removal of
39% of the implants due to sinus tarsi pain. The authors also commented that postoperative sinus tarsi pain was unpredictable.

Cicchinelli et al reported on radiographic outcomes in a retrospective analysis of 28 feet in 20 pediatric patients treated with STA combined with gastrocnemius recession or with STA combined with gastrocnemius recession and medial column reconstruction.(7) Lucaccini et al analyzed clinical and radiographic results of 14 patients (16 feet) with hallux valgus in abnormal pronation syndrome treated with distal osteotomy of the first metatarsal bone and STA performed in 1 stage.(8) In a 2010 study,
Scharer et al conducted a retrospective radiographic evaluation of 39 patients (68 feet) who had received the MBA implant for the treatment of painful pediatric flatfoot deformities.(9) The average age of the patients at the time of surgery was 12 years (range, 6-16 years). Additional procedures included 12 (18%) gastrocnemius recessions, 6 (9%) Achilles tendon lengthening, and 4 (6%) Kidner procedures. At an average 24-month follow-up (range, 6-61 months), there had been 10 (15%) complications requiring reoperation, including implant migration, undercorrection, overcorrection, and persistent pain. The implants were exchanged for either a larger or smaller implant. These case series do not allow comparison with nonsurgical interventions or with other surgical interventions.

An example of a case series with longer follow-up is a 2012 retrospective study by Brancheau et al, which reported mean 36-month follow-up (range, 18-48 months) in 35 patients (60 feet) after use of the MBA implant with adjunct procedures.(10) The mean age of the patients was 14.3 years (range, 5-46 years). Significant changes were observed in radiographic measures (talocalcaneal angle, calcaneocuboid angle, first to second intermetatarsal angle, calcaneal inclination angle, and talar declination angle). Seventeen percent of patients reported that 9 implants (15%) were removed after the initial surgery. Of the 24 patients (68.6%) who answered a subjective questionnaire (in person or by telephone at a mean of 33 months postoperatively), 95.8% reported resolution of the chief presenting complaint, and 79.2% said they were 100% satisfied with their surgical outcome. The contribution of the MBA implant to these results cannot be determined by this study design.

Talotarsal Joint Dislocation

In 2013, Bresnahan et al reported a prospective study of talotarsal stabilization using HyProCure® in 46 feet of 35 patients diagnosed with recurrent and/or partial talotarsal joint dislocation.(11) Patients who had the following characteristics were included: deformity characterized by talar displacement medially, plantarly, and/or anteriorly; collapse of the medial longitudinal arch; hyperpronation about the subtalar joint axis; ability to manipulate the foot to correct the deformity; a prolonged period of pronation or delayed resupination and/or flattening of the arch; and anteroposterior/dorsoplantar and lateral weightbearing radiographs revealing talotarsal  misalignment. 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 had improved from a preoperative score of 69.53 to a postoperative score of 89.27 of 100 (n=30). 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.

Adverse Events

Complications are frequently reported in the literature. Scher et al reported 2 cases of extensive implant reaction in 2 children 2 years after a STA-peg procedure.(12)
Due to the commonly seen complication of severe postoperative pain with failure to reconstitute the longitudinal arch on weight bearing and a residual flatfoot deformity, the authors do not recommend STA in the treatment of painful flexible flatfoot in children. A radiographic study on a bioabsorbable STA found poor outcomes in 3 of 6 patients who met the inclusion criteria and consented to additional imaging.(13) Two patients requested implant removal; a third patient had persistent pain but refused explantation. Radiographic measurement (magnetic resonance imaging or computed tomography) found that these 3 patients had smaller tarsal canal widths than the diameter of the inserted interference screw. The authors noted that the implant length also had to be reduced before implantation. They concluded that the current width and length of commercially available implants may need to be modified and that more research and long-term clinical study are needed.

Cook et al conducted a retrospective case-control study to identify factors that may contribute to failure (explantation) of titanium arthroereisis implants.(14) All patients who required removal of a self-locking wedge-type STA (n=22) were compared in a 1:2 ratio (n=44) with patients with nonexplanted arthroereises who were treated during the same time period. Subjects were matched for preoperative radiographic measurements, age, gender, presenting diagnosis, and length of follow-up. Multivariate
logistic regression showed no significant effect of age, gender, implant size, shape, length of follow-up, implant position, surgeon experience, or concomitant procedures. Patients who required explantation had slightly greater odds of radiographic undercorrection (odds ratio [OR], 1.175) or residual transverse planedominant deformities (OR=1.096). The percentage of explantations in this retrospective analysis was not described.

Clinical Input Received From Physician Specialty Societies and Academic Medical Centers

While the various physician specialty societies and academic medical centers may collaborate with and make recommendations during this process through the provision of appropriate reviewers, input received does not represent an endorsement or position statement by the physician specialty societies or academic medical centers, unless otherwise noted.

2009 Vetting

In response to requests, input was received through 1 physician specialty society (3 reviews) and 5 academic medical centers while this policy was under review in 2009. The input of reviewers was mixed regarding the medical necessity of arthroereisis.

2012 Vetting

In response to requests, input was received through 2 physician specialty societies and 2 academic medical centers while this policy was under review in 2012. Input was mixed, with most reviewers considering this procedure to be investigational.

Summary of Evidence

The evidence in the published medical literature on subalar athroereisis (STA) is inadequate to permit scientific conclusions. The main limitation is the lack of controlled studies comparing use of the implants with other surgical procedures, alone or in combination. Other limitations of the published data is the lack of long-term outcomes, particularly important because 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. Therefore, STA is considered investigational.

Practice Guidelines and Position Statements
2009 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.(15) Therefore this procedure should only be used with special arrangements for clinical governance, consent and audit, or research.

The American College of Foot and Ankle Surgeons (ACFAS) published practice guidelines for the diagnosis and treatment of adult and pediatric flatfoot in 2004 and 2005 (these are not included in the ACFAS library of current clinical practice guidelines).(16,17)

The ACFAS guideline on adult flatfoot states:

“In the adult, arthroereisis is seldom implemented as an isolated procedure. Because of the longterm compensation and adaptation of the foot and adjunctive structures for flatfoot function, other ancillary procedures are usually used for appropriate stabilization. Long-term results of arthroereisis in the adult flexible flatfoot patient have not been established. Some surgeons advise against the subtalar arthroereisis procedure because of the risks associated with implantation of a foreign material, the potential need for further surgery to remove the implant, and the limited capacity of the implant to stabilize the medial column sag directly.”

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.”

U.S. Preventive Services Task Force Recommendations
STA is not a preventive service.

Medicare National Coverage
There is no national coverage determination (NCD). In the absence of an NCD, coverage decisions are left to the discretion of local Medicare carriers.


  1. U.S. Food and Drug Administration. Summary for Kinetikos Medical Incorporated (KMI) Subtalar MBA System™. Available online at: Last accessed August, 2013.
  2. 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 2011; 32(12):1127-39.
  3. Graham ME, Jawrani NT, Chikka A. Extraosseous talotarsal stabilization using HyProCure(R) in adults: a 5-year retrospective follow-up. J Foot Ankle Surg 2012; 51(1):23-9.
  4. Vedantam R, Capelli AM, Schoenecker PL. Subtalar arthroereisis for the correction of planovalgus foot in children with neuromuscular disorders. J Pediatr Orthop 1998; 18(3):294-8.
  5. 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.
  6. Needleman RL. A surgical approach for flexible flatfeet in adults including a subtalar arthroereisis with the MBA sinus tarsi implant. Foot Ankle Int 2006; 27(1):9-18.
  7. Cicchinelli LD, Pascual Huerta J, Garcia Carmona FJ et al. Analysis of gastrocnemius recession and medial column procedures as adjuncts in arthroereisis for the correction of pediatric pes planovalgus: a radiographic retrospective study. J Foot Ankle Surg 2008; 47(5):385-91.
  8. Lucaccini C, Zambianchi N, Zanotti G. Distal osteotomy of the first metatarsal bone in association with sub-talar arthroerisis, for hallux valgus correction in abnormal pronation syndrome. Chir Organi Mov 2008; 92(3):145-8.
  9. Scharer BM, Black BE, Sockrider N. Treatment of painful pediatric flatfoot with Maxwell-Brancheau subtalar arthroereisis implant a retrospective radiographic review. Foot Ankle Spec 2010; 3(2):67-72.
  10. Brancheau SP, Walker KM, Northcutt DR. An analysis of outcomes after use of the Maxwell-Brancheau Arthroereisis implant. J Foot Ankle Surg 2012; 51(1):3-8.
  11. 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
  12. Scher DM, Bansal M, Handler-Matasar S et al. Extensive implant reaction in failed subtalar joint arthroereisis: report of two cases. HSS J 2007; 3(2):177-81.
  13. Saxena A, Nguyen A. Preliminary radiographic findings and sizing implications on patients undergoing bioabsorbable subtalar arthroereisis. J Foot Ankle Surg 2007; 46(3):175-80.
  14. Cook EA, Cook JJ, Basile P. Identifying risk factors in subtalar arthroereisis explantation: a propensity-matched analysis. J Foot Ankle Surg 2011; 50(4):395-401.
  15. National Institute for Clinical Excellence (NICE). Sinus Tarsi Implant Insertion for Mobile Flatfoot: Interventional Procedure Guidance 305. 2009. Available online at: Last accessed August, 2013.
  16. 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 2004; 43(6):341-73.
  17. 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 2005; 44(2):78-113.




CPT    No specific code (see Policy Guidelines)
ICD-9 Diagnosis  734  Flat foot, acquired 
  754.61  Congenital pes planus 
ICD-9 Procedure  81.18  Subtalar joint arthroereisis 
HCPCS  S2117  Arthroereisis, subtalar 
ICD-10-CM (effective 10/1/15)    Investigational for all diagnoses  
  M21.40-M21.42 Flat foot, acquired code range  
ICD-10-PCS (effective 10/1/15) 0SUH0JZ, 0SUJ0JZ Surgical, lower joints, supplement, tarsal joint, open, synthetic substitute, right and left codes  
   0SUH3JZ, 0SUJ3JZ Surgical, lower joints, supplement, tarsal joint, percutaneous, synthetic substitute, right and left codes  
    0SUH4JZ, 0SUJ4JZ Surgical, lower joints, supplement, tarsal joint, percutaneous endoscopic, synthetic substitute, right and left codes 


Arthroereisis, Subtalar
Extraosseous Talotarsal Stabilization
MBA Implant, Subtalar
Subtalar Arthroereisis

Policy History


Date Action Reason
12/14/05 Add policy to Surgery section New policy
04/17/07 Replace Policy Policy update with literature review; reference 4 added; no change in policy statement.
05/08/08 Replace policy  Policy update with literature review; reference 5 added; no change in policy statement. 


Replace policy Policy updated with literature review; reference numbers 6 to 9 added; clinical input reviewed, no change in policy statement.
09/16/10 Replace policy Policy update with literature review through July 2010; references added and reordered; policy statement unchanged
09/01/11 Replace policy Policy update with literature review through July 2011; reference 11 added; policy statement unchanged
9/13/12 Replace policy Policy update with literature review through June 2012; references 2, 3, 10, 14-16 added; clinical input reviewed; policy statement unchanged
9/12/13 Replace policy Policy update with literature search through August 13, 2013; policy statement unchanged
9/11/14 Replace policy Policy updated with literature review through July 25, 2014; reference 11 added; policy statement unchanged