Coverage Policy Manual
Policy #: 1998151
Category: Surgery
Initiated: August 2017
Last Review: February 2019
  Arthroereisis for Pes Planus (Flat Feet) (Subtalar stabilization)

Pes planus is estimated to occur in 1% of children, and is usually corrected with orthotics.  One to two percent of children with pes planus do not correct with orthotics, and continue to have difficulty, including clumsiness, pain in the legs, arch pain, and athletic abstinence.
Surgical procedures have been developed to correct the deformity for those in whom orthotics fail. Surgical approaches fall into four basic categories:
    • Soft-tissue procedures;
    • Bony procedures with osteotomies and arthrodeses;
    • Arthroereisis procedures that affect the subtalar joint motion or axis or motion; and
    • Combinations of the three approaches.
Arthroereisis procedures have been performed since 1946, utilizing the concept of realigning the subtalar joint and holding it neutral should allow for restabilization of the midtarsal joint. Many approaches and prosthetic devices have been used since the original description by Chambers, and are divided by Volger into three categories:
    • Self-locking wedge;
    • Axis altering; and
    • Direct impact.
The self-locking wedge includes the valgus stop prosthesis, the Viladot umbrella, the Addante sphere, the Johnson freeform, the Valenti threaded, and the Subotnick custom-carved plug. The axis altering includes the Smith STA-peg and the Lundeen modified STA-peg. Direct impact includes the Sgarlato mushroom and the Pisani composite screw. The MBA implant was not available when Volger did this classification, but has been likened to the STA-peg device by podiatrists.
The SubFix™ arthroereisis implant (Memometal Technologies, Bruz, France) received U.S. Food and Drug Administration (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.”  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).
There is no CPT code specific for this procedure.  It is appropriately billed with 28899.
On October 1, 2005, the following HCPCS S code became available:
S2117: Arthroereisis, subtalar

Arthroereisis has been performed by the Podiatric profession for 50 years, but unfortunately there are no long-term outcome studies on any of the various techniques.  Arthroereisis is not covered based on benefit certificate primary coverage criteria that there be scientific evidence of effectiveness.

For contracts without primary coverage criteria, arthroereisis is considered investigational.  Investigational services are an exclusion in the member certificate of coverage.

Treatment of pes planus is an exclusion in the member certificate of coverage.

A review of the literature finds no randomized controlled trials and no comparative studies for effectiveness.
2006-2007 Update
A search of the MEDLINE database for the period of September 2005 through January 2007 found no evidence to prompt a change in the policy statement. Several retrospective case series were published. One of these 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. (Needleman, 2006) However, since results were not compared with controls receiving reconstructive surgery without subtalar arthroereisis, 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. No prospective controlled studies were identified.
2008 Update
A search of the MEDLINE database for the period of February 2007 through March 2008 identified one radiographic study of bioabsorbable subtalar arthroereisis. (Saxena, Nguyen 2007) Six patients met the inclusion criteria and consented to additional imaging with an average follow-up of 14 months (range of 12-50 months). Two patients requested implant removal; a third had persistent pain but refused explantation. Radiographic measurement (MRI or CT) 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 prior to 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. Subtalar arthroereisis has not been shown to be as beneficial as established alternatives and the policy statement remains unchanged.
2012 Update
The policy is being updated with a literature search using the MEDLINE database through July 2012.  There was no new literature identified that would prompt a change in the coverage statement.
Several case series with small numbers of patients were identified reporting outcomes of a combination of surgical interventions in which STA was one component. For example, Adelman and colleagues, in a study from the United States, reported on a retrospective analysis of 10 patients (Adelman, 2008). The authors described this as a pilot study, and they reported on changes in 7 radiographic measurements. Cicchinelli et al. in a study from Spain, also 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 (Cicchinelli, 2008).  The authors reported that gastrocnemius recession had a notable effect on correction of transverse plane deformity when used as an adjunct to STA; however, medial column reconstruction had a negative impact on the degree of correction in the transverse plane when used as an adjunct to STA and gastrocnemius recession. In another study from Europe, 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 (Lucaccini, 2008).  In a U.S. study from 2010, Scharer and colleagues conducted a retrospective radiographic evaluation of 39 patients (68 feet) who had received the MBA implant for the treatment of painful pediatric flatfoot deformities (Scharer, 2010). 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.
Cook et al. reported a retrospective case-control study in 2011 to identify factors that may contribute to failure (explantation) of titanium arthroereisis implants (Cook, 2011).  All patients who required removal of a self-locking wedge-type subtalar arthroereisis (n=22) were compared in a 1:2 ratio (n=44) to 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 plane-dominant deformities (OR: 1.096). The percentage of explantations in this retrospective analysis was not described.
2013 Update
A literature search conducted using the MEDLINE database through July 2012 did not identify any new information that would prompt a change in the coverage statement. The following is a summary of the key identified literature.
In 2011, Metcalfe et al. published a systematic review of the literature on subtalar arthroereisis for pediatric flexible flatfoot. (Metcalfe, 2011)  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 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.
A retrospective study was published in 2012 (Brancheau, 2012) which reported mean 36-month follow-up (range 18 to 48 months) in 35 patients (60 feet) after use of the Maxwell-Brancheau Arthroereisis (MBA) implant with adjunct procedures. 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.
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 (Graham, 2012). 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 on their foot functional abilities, and 80% of cases 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.
2014 Update
A literature search conducted through August 2014 did not reveal any new information that would prompt a change in the coverage statement. The key identified literature is summarized below.
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 (Bresnahan, 2013). 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
2016 Update
A literature search conducted through January 2016 did not reveal any new information that would prompt a change in the coverage statement. The key identified literature is summarized below.
In 2015, Chong and colleagues reported a small prospective nonrandomized trial that compared STA with lateral column calcaneal lengthening for the treatment of 24 painful flatfeet in children (Chong, 2015). Seven children (13 feet) enrolled at the Primary Children’s Medical Center were treated with arthroereisis and 8 children (11 feet) enrolled at the Shriners Hospital for Children were treated with lateral column lengthening. Children who underwent STA had a small incision with insertion of the implant and were placed in below-knee walking casts for 3 weeks. Children treated with lateral column lengthening had an opening wedge osteotomy with insertion of a wedge of cadaveric bone and were placed in non-weight-bearing casts for 1 month and walker type boots for another month. Outcomes at a mean of 12.7 months after surgery included radiographs, foot pressure, kinematic analysis and the Oxford Ankle-Foot Questionnaire for Children. The 2 groups showed similar improvements in the lateral talo-first metatarsal angle and talonavicular coverage and in kinematics. Both groups showed a statistically significant lateralization of the hindfoot and midfoot center of pressure (p<0.01). There were no between-group differences in any of the clinical or functional outcomes. On within-group comparison, only the STA group had a statistically significant reduction in time on the hindfoot (p=0.01). Both groups had improvements in the parental and child scores on the Oxford questionnaire, but only the STA group had a statistically significant improvement in this small sample. There were 2 complications in each group, with removal of the hardware in 1 patient and removal of the implant in 2 patients. The improvement in pain and foot position was retained following implant removal.
Ongoing and Unpublished Clinical Trials
A search of in January 2016 did not identify any ongoing or unpublished trials that would likely influence this review.
2018 Update
Annual policy review completed with a literature search using the MEDLINE database through February 2018. No new literature was identified that would prompt a change in the coverage statement.
2019 Update
Annual policy review completed with a literature search using the MEDLINE database through January 2019. No new literature was identified that would prompt a change in the coverage statement.

0335TExtra-osseous subtalar joint implant for talotarsal stabilization
0510TRemoval of sinus tarsi implant
0511TRemoval and reinsertion of sinus tarsi implant
28446Open osteochondral autograft, talus (includes obtaining graft[s])
28899Unlisted procedure, foot or toes
S2117Arthroereisis, subtalar

References: Adelman VR, Szczepanski JA, Adelman RP.(2008) Radiographic evaluation of endoscopic gastrocnemius recession, subtalar joint arthroereisis, and flexor tendon transfer for surgical correction of stage II posterior tibial tendon dysfunction: a pilot study. J Foot Ankle Surg 2008; 47(5):400-8.

Brancheau S, Maxwell J, Ritchey KL, et al.(1996) The Valenti STJ Arthroereisis Implant: A Ten-Year Retrospective Study. Reconstructive Surg Foot Leg; Update 1996; Chapter 8; pp 44-53.

Brancheau SP, Walker KM, Northcutt DR.(2012) An analysis of outcomes after use of the Maxwell-Brancheau Arthroereisis implant. J Foot Ankle Surg 2012; 51(1):3-8.

Bresnahan PJ, Chariton JT, Vedpathak A.(2013) Extraosseous talotarsal stabilization using HyProCure®: preliminary clinical outcomes of a prospective case series. J Foot Ankle Surg. Mar-Apr 2013;52(2):195-202. PMID 23313499

Chong DY, MacWilliams BA, Hennessey TA, et al.(2015) Prospective comparison of subtalar arthroereisis with lateral column lengthening for painful flatfeet. J Pediatr Orthop B. Jul 2015;24(4):345-353. PMID 25856275

Cicchinelli LD, Pascual Huerta J, Garcia Carmona FJ et al.(2008) 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.

Cohen-Sobel E, Giorgin R, Velez Z.(1995) Combined Technique for Surgical Correction of Pediatric Severe Flexible Flatfoot. J Foot Ankle Surg 1995; 34:183-94.

Cook EA, Cook JJ, Basile P.(2011) Identifying Risk Factors in Subtalar Arthroereisis Explantation: A Propensity-matched Analysis. J Foot Ankle Surg 2011; 50(4):395-401.

Graham ME, Jawrani NT, Chikka A.(2012) Extraosseous talotarsal stabilization using HyProCure(R) in adults: a 5-year retrospective follow-up. J Foot Ankle Surg 2012; 51(1):23-9.

Lee MS, Vanore JV, et al.(2005) Diagnosis and treatment of adult flatfoot. J Foot Ankle Surg, 2005; 44:78-113.

Lucaccini C, Zambianchi N, Zanotti G.(2008) 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.

Metcalfe SA, Bowling FL, Reeves ND.(2011) Subtalar joint arthroereisis in the management of pediatric flexible flatfoot: a critical review of the literature. Foot Ankle Int 2011; 32(12):1127-39.

Needleman RL.(2006) A surgical approach for flexible flat feet in adults including a subtalar arthroereisis with the MBA sinus tarsi implant. Foot Ankle Int, 2006; 27:9-18.

Saxena A, Nguyen A.(2007) Preliminary radiographic findings and sizing implications on patients undergoing bioabsorbable subtalar arthroereisis. J Foot Ankle Surg, 2007; 46:175-80.

Scharer BM, Black BE, Sockrider N.(2010) Treatment of painful pediatric flatfoot with Maxwell-Brancheau subtalar arthroereisis implant a retrospective radiographic review. Foot Ankle Spec 2010; 3(2):67-72.

Smith SD, Ocampo RF.(1997) Subtalar Arthroereisis and Associated Procedures. Clin Podiatr Med Surg 1997; 14:87-98.

Group specific policy will supersede this policy when applicable. This policy does not apply to the Wal-Mart Associates Group Health Plan participants or to the Tyson Group Health Plan participants.
CPT Codes Copyright © 2019 American Medical Association.