Subtalar Arthroereisis

Number 7.01.104

Effective Date November 20, 2014

Revision Date(s) 11/10/14; 11/11/13; 11/13/12; 10/11/11; 11/09/10; 10/13/09; 06/10/08; 08/14/07; 04/11/06

Replaces N/A


Subtalar arthroereisis is considered investigational.

Related Policies



Policy Guidelines




Extra-osseous subtalar joint implant for talotarsal stabilization


Arthrodesis; subtalar


Unlisted procedure, foot or toes



Arthroereisis, subtalar

Note: This policy only applies to subtalar arthroereisis (sinus tarsi implant or stent) surgery, a corrective operation to limit range of motion at the subtalar joint in cases of excessive mobility.

*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.


Arthroereisis (also referred to as arthroisis) is the limitation of movement across a joint. Subtalar arthroereisis (STA) or extraosseous talotarsal stabilization (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.


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

  • number of implants have received marketing clearance through FDA’s 510(k) pathway. For example:
  • HyProCure® Subtalar Implant System/Extra Osseos Fixation Device (GraMedica) received marketing clearance in 2004 (K042030)
  • SubFix™ arthroereisis implant (Memometal Technologies, Bruz, France) received FDA marketing clearance in 2010 (K093820)
  • Arthrex ProStop Plus™ (Arthrex, Naples, FL) received marketing clearance in 2008 (K071456)
  • 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 before 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)
  • 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.
  • devices include:
  • Osteomed Talar-Fit™ (K031155)
  • Orthopedics Subtalar Peg (K032902, K033046)
  • Implant Talus of Vilex (TOV, K041289)
  • (K080280), Wright Medical Smith Sta-Peg (K792670). FDA product code: HWC


Medical policies are systematically developed guidelines that serve as a resource for Company staff when determining coverage for specific medical procedures, drugs or devices. Coverage for medical services is subject to the limits and conditions of the member benefit plan. Members and their providers should consult the member benefit booklet or contact a customer service representative to determine whether there are any benefit limitations applicable to this service or supply. This medical policy does not apply to Medicare Advantage.

Benefit Application



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 non-validated 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 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.

One case series that was not confounded by adjunctive procedures and that had a relatively long follow-up 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 five 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 one 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, six (9%) Achilles tendon lengthening, and four (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, under correction, 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 to 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 to 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 weight-bearing 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 under correction (odds ratio [OR], 1.175) or residual transverse plane-dominant 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.


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.


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 subtalar 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 long-term 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 October 16, 2014.
  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. Dec 2011; 32(12):1127-1139. PMID 22381197
  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. Jan-Feb 2012; 51(1):23-29. PMID 22196455
  4. Vedantam R, Capelli AM, Schoenecker PL. Subtalar arthroereisis for the correction of planovalgus foot in children with neuromuscular disorders. J Pediatr Orthop. May-Jun 1998; 18(3):294-298. PMID 9600551
  5. Nelson SC, Haycock DM, Little ER. Flexible flatfoot treatment with arthroereisis: radiographic improvement and child health survey analysis. J Foot Ankle Surg. May-Jun 2004; 43(3):144-155. PMID 15181430
  6. Needleman RL. A surgical approach for flexible flatfeet in adults including a subtalar arthroereisis with the MBA sinus tarsi implant. Foot Ankle Int. Jan 2006; 27(1):9-18. PMID 16442023
  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. Sep-Oct 2008; 47(5):385-391. PMID 18725117
  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. Dec 2008; 92(3):145-148. PMID 19082522
  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. Apr 2010; 3(2):67-72. PMID 20400415
  10. Brancheau SP, Walker KM, Northcutt DR. An analysis of outcomes after use of the Maxwell-Brancheau Arthroereisis implant. J Foot Ankle Surg. Jan-Feb 2012; 51(1):3-8. PMID 22196453
  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. Sep 2007; 3(2):177-181. PMID 18751791
  13. Saxena A, Nguyen A. Preliminary radiographic findings and sizing implications on patients undergoing bioabsorbable subtalar arthroereisis. J Foot Ankle Surg. May-Jun 2007; 46(3):175-180. PMID 17466243
  14. Cook EA, Cook JJ, Basile P. Identifying risk factors in subtalar arthroereisis explantation: a propensity-matched analysis. J Foot Ankle Surg. Jul-Aug 2011; 50(4):395-401. PMID 21708340
  15. National Institute for Clinical Excellence (NICE). Sinus Tarsi Implant Insertion for Mobile Flatfoot: Interventional Procedure Guidance 305. 2009. Available online at: Last accessed October 7, 2014.
  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. Nov-Dec 2004; 43(6):341-373. PMID 15605048
  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. Mar-Apr 2005; 44(2):78-113. PMID 15768358
  18. Blue Cross Blue Shield Association (BCBSA) Medical Policy Reference Manual, Subtalar Arthroereisis. Medical Policy Reference Manual, Policy 7.01.104, 2014.







Extra-osseous subtalar joint implant for talotarsal stabilization



Arthrodesis; subtalar



Unlisted procedure, foot or toes

ICD-9 Diagnosis


Flat foot, acquired



Congenital pes planus

(effective 10/01/15)

M21.40 - M21.42

Flat foot, acquired code range

(effective 10/01/15)


Surgical, lower joints, supplement, tarsal joint, open, synthetic substitute, right and left codes



Surgical, lower joints, supplement, tarsal joint, percutaneous, synthetic substitute, right and left codes



Surgical, lower joints, supplement, tarsal joint, percutaneous endoscopic, synthetic substitute, right and left codes



Arthroereisis, subtalar

Type of Service



Place of Service









Add to Surgery Section - New Policy


Disclaimer and Scope update - No other changes


Replace policy - Policy updated with literature review; references added. No change in policy statement.


Code Updated - CPT code 28725 was deleted and added 28735.


Replace policy - Policy updated with literature search; no change to the policy statement. Reference added.


Replace policy - Policy updated with literature search; no change to the policy statement. Reference added.


Replace policy - Policy updated with literature review through July 2010; references added and reordered. The policy statement remains unchanged.


Replace policy – Policy update with literature review through July 2011; reference 11 added; policy statement unchanged. ICD-10 codes added to policy.


Codes updated; CPT 28725 and 29907 removed from the policy as they do not apply.


Replace policy - Policy guidelines revised with addition of clarification for Arthroereisis (joint implant) surgery vs. Arthrodesis (joint fusion) surgery. Rationale section revised based on literature review through June 2012 and; clinical input. References 2, 3, 10, 14-16 added; others renumbered or removed. Policy statement unchanged.


Replace policy. A literature review through August 13, 2013 did not prompt the addition of any new references. Policy statement unchanged. Codes 0335T (new code), 28735 and 28899 added to the policy.


Coding Update. Code 81.18 was removed per ICD-10 mapping project; this code is not utilized for adjudication of policy.


Annual Review. Policy updated with literature review through July 25, 2014 Reference 11 added; others renumbered/removed. Policy statement unchanged.

Disclaimer: This medical policy is a guide in evaluating the medical necessity of a particular service or treatment. The Company adopts policies after careful review of published peer-reviewed scientific literature, national guidelines and local standards of practice. Since medical technology is constantly changing, the Company reserves the right to review and update policies as appropriate. Member contracts differ in their benefits. Always consult the member benefit booklet or contact a member service representative to determine coverage for a specific medical service or supply. CPT codes, descriptions and materials are copyrighted by the American Medical Association (AMA).
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