Back To Search Results

Arthroereisis

Editor: Mark A. Dreyer Updated: 6/8/2024 2:01:05 PM

Introduction

The term "arthroereisis" comes from the combination of the Greek words arthro- (joint) and -ereisis (the action of bracing against or pushing against something).[1] Arthroereisis refers to a surgical procedure used to treat flatfoot, aiming to reestablish a medial foot arch and limit but not completely block subtalar joint movement from going into eversion.[2] In 1946, Chambers initially introduced the concept of "manipulation" of the subtalar joint to address flatfoot. This involved the impaction of a wedge-shaped bone block into the anterior border of the posterior facet of the calcaneus, a procedure known as an "abduction block," which prevents excessive forward displacement of the talus upon the calcaneus.[3]

A few years later, Baker and Hill advocated a lateral opening-wedge osteotomy of the posterior joint surface to achieve the same goal.[4] Haraldsson was the first to coin the term "arthrohisis" to describe the insertion of a wedge graft into the sinus tarsi.[5][6] In 1970, Lelièvre first used the term "arthroereisis" to describe a similar technique involving the insertion of a bone graft into the sinus tarsi, secured with a temporary staple.[7] The concept of supporting the talus on the calcaneus by inserting an external synthetic implant in the sinus tarsi quickly evolved. In 1974, Subotnick proposed the first device to achieve this, and since then, various solutions have been introduced, differing in form (block, sphere, screw, cap, cylinder) and composition (polyethylene, silastic, titanium, or a combination of these).[8][9]

Anatomy and Physiology

Register For Free And Read The Full Article
Get the answers you need instantly with the StatPearls Clinical Decision Support tool. StatPearls spent the last decade developing the largest and most updated Point-of Care resource ever developed. Earn CME/CE by searching and reading articles.
  • Dropdown arrow Search engine and full access to all medical articles
  • Dropdown arrow 10 free questions in your specialty
  • Dropdown arrow Free CME/CE Activities
  • Dropdown arrow Free daily question in your email
  • Dropdown arrow Save favorite articles to your dashboard
  • Dropdown arrow Emails offering discounts

Learn more about a Subscription to StatPearls Point-of-Care

Anatomy and Physiology

Flatfoot is a frequently encountered deformity that is characterized by:

  • Abduction of the forefoot
  • Eversion of the hindfoot and calcaneus
  • Collapsed medial arch
  • Medial rotation and plantar flexion of the talus [10][11]

The majority of authors tend to distinguish between pediatric/adolescent flatfoot and adult flatfoot as separate entities.[12]

Pediatric

Distinguishing between rigid and flexible flat feet is crucial. Rigid flatfoot is often symptomatic and associated with conditions such as bony coalitions, rheumatoid or posttraumatic arthritis, neurological or neuromuscular disorders, or other underlying causes. Flexible flatfoot is usually idiopathic and characterized by the restoration of the medial arch during a physical examination when standing on tiptoes or performing the Jack test, where the medial arch rises with passive dorsiflexion of the toes.[13] Flexible flatfoot can often be corrected by arthroereisis as a stand-alone procedure.

There is a general consensus that flatfoot in the first few years of life is considered physiological; it frequently corrects itself by the time a child reaches age 10.[14] However, the deformity can often cause parental concern, leading to further medical referrals. While children with flatfoot may often walk without issues, they may occasionally complain of pain over the distal fibula, the medial portion of the midfoot, the sinus tarsi, and the medial aspect of the heel.[15]

Adult

According to clinical and radiographic criteria developed by Johnson and Strom (applied by Myerson), pes planus in adults is frequently linked to dysfunction of the tibialis posterior tendon, a condition often seen in African-American populations more than Caucasian (38% vs 16%).[16][17]

There are 3 categories of causes:

  • Articular (rheumatoid arthritis, degenerative primary midfoot and hindfoot arthritis, connective tissue disease)
  • Osseous (congenital or posttraumatic)
  • Neurological or neuromuscular diseases

Unlike in children, flatfoot in adults is often a permanent acquired deformity that can cause discomfort during daily activities, difficulty with shoe fitting, and persistent functional impairment related to walking propulsion.[12][18] Without treatment, these symptoms are likely to worsen over time.[19]

Indications

Indications in the Pediatric Population

Subtalar arthroereisis may be utilized as a standalone procedure or in conjunction with tendon releases to address painful congenital flexible flatfoot.[20][21] This technique involves inserting an implant into the sinus tarsi, a space between the talus and calcaneus bones, to restrict excessive subtalar joint movement and correct hindfoot eversion deformities in flat feet. Effective in symptomatic flexible flatfoot cases, where the arch is correctable, arthroereisis aids by stabilizing the foot arch during weight-bearing, restoring it when the foot is not bearing weight. This technique is also commonly employed as an adjunctive treatment for rigid flatfoot conditions associated with tibialis posterior tendon dysfunction, tarsal coalition, and accessory navicular bone syndrome.[22] 

Indications in the Adult Population

In adults, the initial treatment for flatfoot, particularly secondary to tibialis posterior tendon dysfunction, commonly involves the use of insoles, with surgery reserved for cases where conservative measures fail.[23] However, the role of arthroereisis differs in adults compared to pediatric patients due to the structural nature of adult flatfoot. While arthroereisis is rarely performed as a standalone procedure in adults, it is often combined with soft tissue and bony procedures to augment the antipronation effect and support the medial arch and tibialis posterior tendon.[24][25] Despite insights from various specialists, there remains insufficient research to establish arthroereisis as a primary option for adult flatfoot management.[26]

Contraindications

The following are contraindications to arthroereisis:

  • Unstable midtarsal joint
    • This condition, which can occur in flexible flatfoot, is not addressed by arthroereisis. The implant may result in discomfort, subluxation, or arthritis by placing more strain on the midtarsal joint. Consequently, osteotomy or midtarsal arthrodesis may be necessary in these cases.[27]
  • Arthritis
    • Arthroereisis is not recommended for patients with arthritis of the subtalar or midtarsal joints, as the implant may aggravate the inflammation and degeneration of the joint cartilage. Arthroereisis may also interfere with the normal biomechanics of the joint and cause further damage. Arthritis may also affect the implant fixation and stability, increasing the risk of implant failure or migration.[28] Therefore, arthroereisis is unsuitable for arthritic patients and may require alternative treatments such as joint debridement, arthroplasty, or arthrodesis.[29]
  • Rigid equinus
    • Patients with rigid equinus, characterized by a fixed plantarflexion contracture of the ankle joint, typically do not respond favorably to arthroereisis. This condition can lead to excessive stress on the forefoot and impaired performance of the windlass mechanism, potentially resulting in the collapse of the medial longitudinal arch. Since arthroereisis restricts subtalar joint mobility without addressing the equinus deformity, it may exacerbate symptoms in such cases. Therefore, arthroereisis is not recommended as a standalone treatment for rigid equinus and may require a combination with other interventions, such as gastrocnemius recession or Achilles tendon lengthening.[29][30]

Equipment

There are different types of implants and techniques for arthroereisis, such as expandable sinus tarsi implants, lateral calcaneus stop screws, and absorbable implants. A recent study compared the clinical, radiographic, and pedobarographic outcomes of 3 different methods of arthroereisis and found that they all achieved comparable improvements in foot function, alignment, and pressure distribution. However, the study also reported a higher incidence of implant-related complications with sinus tarsi implants than with screw arthroereisis.[31]

Technique or Treatment

The minimally invasive surgical technique is typically preferred for surgeons performing arthroereisis procedures. This method involves making a lateral incision, ranging from 1 to 4 cm, positioned parallel to the skin tension lines and just anterior and inferior to the tip of the lateral malleolus. After debriding the sinus tarsi, the hindfoot is manually supinated to correct the pronated deformity.

For self-locking implants, a probe is inserted to determine the tunnel direction, and successive trial implants are used under fluoroscopy to determine the appropriate size.[2][25] In cases involving impact-blocking instruments like the calcaneo-stop screw, the screw is inserted after drilling a guide wire either in the talus (retrograde approach) or calcaneus (anterograde technique).[32] 

Postoperative instructions and protocols vary among surgeons, with weight-bearing typically postponed for 6 weeks when combined with other operations. Still, immediate weight-bearing may be allowed with or without a cast for 5 to 10 days when performed alone.[33]

Complications

Complications of arthroereisis can be broadly categorized into 4 groups:

  • Implant biomaterial failure (screw loosening, wear, or breakage)
  • Inflammatory reaction (painful sinus tarsitis, peroneal spasm, stiff equinus or fourth metatarsal stress fracture)
  • Technical error (extrusion, malcorrection, overcorrection, or undercorrection)
  • Those related to use in contraindicated cases (unstable midtarsal joint, arthritis, rigid equinus) [34][35]

The most common complication associated with arthroereisis is pain around the sinus tarsi, although this typically resolves upon implant removal.[36] However, there is uncertainty regarding complication and removal rates. As a recent literature analysis indicates, reported complication rates range from 4.8% to 18.6%, while removal rates range from 7.1% to 19.3%.[37] These figures contradict many authors' observations that not all complications require additional surgery and may resolve spontaneously. Earlier studies showed that up to 40% of patients needed implant removal.[38] However, the lack of long-term follow-up and comprehensive analyses underscores the need for thorough prospective research in the future.

Furthermore, case reports have outlined a few rare but potentially severe issues, such as talar fracture and postoperative subtalar fusion. Recent studies, however, indicate a relatively low overall complication rate, ranging from 0% to 11%. Despite this, a 2015 web-based survey revealed surprising data indicating that 33% of American Orthopedic Foot and Ankle Society members who had previously conducted subtalar arthroereisis opted to discontinue the procedure due to its high failure rate and the need for implant removal.[22] This suggests that research on subtalar arthroereisis may be influenced by publication bias, favoring the reporting of positive outcomes. Additionally, the survey states that a greater share of foreign surgeons performs arthroereisis than their American counterparts, potentially influenced by challenges in payment from health insurance companies.[22]

Previous research suggests that implants should remain in place for at least 2 years for proper bone and soft tissue adaptation before removal.[39] Delays of 6 to 18 months have been noted in older literature, particularly when used as an adjunct surgery for adult flatfoot to capitalize on the impact of the implant on other surgical operations.[8] However, there is no precise timeframe for permanent repair. Studies investigating predictors of implant removal in adults indicate significant unplanned explantation rates of up to 30% to 40%. Risk factors include radiographic undercorrection of deformity and larger implant size.[40] In these studies, arthroereisis was often performed as an adjunct operation with various implant types. However, older literature suggests that a higher removal rate does not always correlate with size and radiographic parameters of correction. Establishing a precise correlation between explantation risk and potential risk factors is still necessary.

Clinical Significance

Arthroereisis offers several advantages over traditional open surgery techniques. Firstly, it is minimally invasive, requiring smaller incisions and causing less disruption to soft tissues. This results in a shorter hospital stay, quicker recovery time, and reduced postoperative complications such as edema and pain. Additionally, arthroereisis preserves the natural anatomy and biomechanics of the foot, allowing for future growth and development. Notably, the procedure is reversible, and the implant can be easily removed if necessary, providing flexibility in treatment options. 

Despite its clinical significance, arthroereisis is not without challenges, as implant-related complications and the need for subsequent implant removal may occur. Thus, careful patient selection and postoperative management are crucial to optimizing outcomes. Overall, arthroereisis represents an important therapeutic option in the management of pediatric and adult flatfoot deformities, providing patients with improved foot function and quality of life.

Enhancing Healthcare Team Outcomes

Effective management of arthroereisis requires a collaborative approach involving various healthcare professionals to optimize patient-centered care, outcomes, and safety. Physicians, advanced practitioners, nurses, pharmacists, and other team members must possess the necessary skills and expertise to perform their respective roles effectively. Surgeons need expertise in arthroereisis techniques, including implant placement and postoperative management. Advanced practitioners are crucial in patient assessment, education, and follow-up care, ensuring treatment plans are tailored to individual needs. Nurses provide essential support in perioperative care, monitoring patients for complications and facilitating their recovery. Pharmacists contribute by ensuring appropriate medication management, including pain control and prevention against infection. Physical therapists guide postoperative rehabilitation efforts. 

Interprofessional communication is vital for care coordination and optimizing patient outcomes. Healthcare professionals must communicate effectively to exchange information, coordinate treatment plans, and promptly address concerns or complications. Regular multidisciplinary team meetings can facilitate collaboration, allowing each member to contribute their expertise and insights. Clear communication channels enhance patient safety by minimizing errors and ensuring all team members align with the treatment goals. Additionally, ongoing education and training programs help healthcare professionals stay updated on the latest advancements in arthroereisis techniques and patient care, further enhancing team performance and patient outcomes.

References


[1]

Nevalainen MT, Roedl JB, Zoga AC, Morrison WB. Imaging findings of arthroereisis in planovalgus feet. Radiology case reports. 2016 Dec:11(4):398-404     [PubMed PMID: 27920869]

Level 3 (low-level) evidence

[2]

Ghali A, Mhapankar A, Momtaz D, Driggs B, Thabet AM, Abdelgawad A. Arthroereisis: Treatment of Pes Planus. Cureus. 2022 Jan:14(1):e21003. doi: 10.7759/cureus.21003. Epub 2022 Jan 7     [PubMed PMID: 35154977]


[3]

CHAMBERS EF. An operation for the correction of flexible flat feet of adolescents. Western journal of surgery, obstetrics, and gynecology. 1946 Mar:54():77-86     [PubMed PMID: 21020329]


[4]

BAKER LD, HILL LM. FOOT ALIGNMENT IN THE CEREBRAL PALSY PATIENT. The Journal of bone and joint surgery. American volume. 1964 Jan:46():1-15     [PubMed PMID: 14104310]


[5]

HARALDSSON S. Operative treatment of pes planovalgus staticus juvenilis. Preliminary communication. Acta orthopaedica Scandinavica. 1962:32():492-8     [PubMed PMID: 13952702]


[6]

HARALDSSON S. PES PLANO-VALGUS STATICUS JUVENILIS AND ITS OPERATIVE TREATMENT. Acta orthopaedica Scandinavica. 1965:35():234-56     [PubMed PMID: 14274676]


[7]

LeLièvre J. Current concepts and correction in the valgus foot. Clinical orthopaedics and related research. 1970 May-Jun:70():43-55     [PubMed PMID: 5445732]


[8]

Subotnick SI. The subtalar joint lateral extra-articular arthroereisis: a preliminary report. Journal of the American Podiatry Association. 1974 Sep:64(9):701-11     [PubMed PMID: 4605345]


[9]

Kwiatkowski M, Guszczyn T, Sobolewski A, Sar M, Hermanowicz A. Migration of Subtalar Implants in Paediatric Flatfoot Correction: A Pilot Study in Synthetic Bone Models. Ortopedia, traumatologia, rehabilitacja. 2022 Apr 30:24(2):121-132. doi: 10.5604/01.3001.0015.8374. Epub     [PubMed PMID: 35550354]

Level 3 (low-level) evidence

[10]

Mosca VS. Flexible flatfoot in children and adolescents. Journal of children's orthopaedics. 2010 Apr:4(2):107-21. doi: 10.1007/s11832-010-0239-9. Epub 2010 Feb 18     [PubMed PMID: 21455468]


[11]

Atik A, Ozyurek S. Flexible flatfoot. Northern clinics of Istanbul. 2014:1(1):57-64. doi: 10.14744/nci.2014.29292. Epub 2014 Aug 3     [PubMed PMID: 28058304]


[12]

Arain A, Harrington MC, Rosenbaum AJ. Adult-Acquired Flatfoot. StatPearls. 2024 Jan:():     [PubMed PMID: 31194335]


[13]

Halabchi F, Mazaheri R, Mirshahi M, Abbasian L. Pediatric flexible flatfoot; clinical aspects and algorithmic approach. Iranian journal of pediatrics. 2013 Jun:23(3):247-60     [PubMed PMID: 23795246]


[14]

Vergara-Amador E, Serrano Sánchez RF, Correa Posada JR, Molano AC, Guevara OA. Prevalence of flatfoot in school between 3 and 10 years. Study of two different populations geographically and socially. Colombia medica (Cali, Colombia). 2012 Apr:43(2):141-6     [PubMed PMID: 24893055]


[15]

Houghton KM. Review for the generalist: evaluation of pediatric foot and ankle pain. Pediatric rheumatology online journal. 2008 Apr 9:6():6. doi: 10.1186/1546-0096-6-6. Epub 2008 Apr 9     [PubMed PMID: 18400098]


[16]

Abousayed MM, Tartaglione JP, Rosenbaum AJ, Dipreta JA. Classifications in Brief: Johnson and Strom Classification of Adult-acquired Flatfoot Deformity. Clinical orthopaedics and related research. 2016 Feb:474(2):588-93     [PubMed PMID: 26472584]


[17]

Golightly YM, Hannan MT, Dufour AB, Jordan JM. Racial differences in foot disorders and foot type. Arthritis care & research. 2012 Nov:64(11):1756-9. doi: 10.1002/acr.21752. Epub     [PubMed PMID: 22674897]


[18]

Mehdi N, Bernasconi A, Lintz F. Tarsal coalition in adults. Orthopaedics & traumatology, surgery & research : OTSR. 2024 Feb:110(1S):103761. doi: 10.1016/j.otsr.2023.103761. Epub 2023 Nov 17     [PubMed PMID: 37979676]


[19]

Toullec E. Adult flatfoot. Orthopaedics & traumatology, surgery & research : OTSR. 2015 Feb:101(1 Suppl):S11-7. doi: 10.1016/j.otsr.2014.07.030. Epub 2015 Jan 13     [PubMed PMID: 25595429]


[20]

Wang S, Chen L, Yu J, Zhang C, Huang JZ, Wang X, Ma X. 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. Orthopaedic surgery. 2021 Feb:13(1):175-184. doi: 10.1111/os.12864. Epub 2020 Dec 17     [PubMed PMID: 33332772]


[21]

Nelson SC, Haycock DM, Little ER. Flexible flatfoot treatment with arthroereisis: radiographic improvement and child health survey analysis. The Journal of foot and ankle surgery : official publication of the American College of Foot and Ankle Surgeons. 2004 May-Jun:43(3):144-55     [PubMed PMID: 15181430]

Level 3 (low-level) evidence

[22]

Shah NS, Needleman RL, Bokhari O, Buzas D. 2013 Subtalar Arthroereisis Survey: The Current Practice Patterns of Members of the AOFAS. Foot & ankle specialist. 2015 Jun:8(3):180-5. doi: 10.1177/1938640015578514. Epub 2015 Mar 26     [PubMed PMID: 25813779]

Level 3 (low-level) evidence

[23]

Zhai JN, Qiu YS, Wang J. Effects of orthotic insoles on adults with flexible flatfoot under different walking conditions. Journal of physical therapy science. 2016 Nov:28(11):3078-3083     [PubMed PMID: 27942124]

Level 2 (mid-level) evidence

[24]

Ozan F, Doğar F, Gençer K, Koyuncu Ş, Vatansever F, Duygulu F, Altay T. Symptomatic flexible flatfoot in adults: subtalar arthroereisis. Therapeutics and clinical risk management. 2015:11():1597-602. doi: 10.2147/TCRM.S90649. Epub 2015 Oct 16     [PubMed PMID: 26527876]


[25]

Needleman RL. A surgical approach for flexible flatfeet in adults including a subtalar arthroereisis with the MBA sinus tarsi implant. Foot & ankle international. 2006 Jan:27(1):9-18     [PubMed PMID: 16442023]


[26]

Tao X, Chen W, Tang K. Surgical procedures for treatment of adult acquired flatfoot deformity: a network meta-analysis. Journal of orthopaedic surgery and research. 2019 Feb 21:14(1):62. doi: 10.1186/s13018-019-1094-0. Epub 2019 Feb 21     [PubMed PMID: 30791933]

Level 1 (high-level) evidence

[27]

Bernasconi A, Lintz F, Sadile F. The role of arthroereisis of the subtalar joint for flatfoot in children and adults. EFORT open reviews. 2017 Nov:2(11):438-446. doi: 10.1302/2058-5241.2.170009. Epub 2017 Nov 8     [PubMed PMID: 29218229]


[28]

Szesz A, Małecki K, Sibiński M, Niedzielski KR. An evaluation of subtalar titanium screw arthroereisis for the treatment of symptomatic paediatric flatfeet - early results. BMC musculoskeletal disorders. 2023 Oct 19:24(1):825. doi: 10.1186/s12891-023-06937-2. Epub 2023 Oct 19     [PubMed PMID: 37858058]


[29]

Erard MUE, Sheean MAJ, Sangeorzan BJ. Triple Arthrodesis for Adult-Acquired Flatfoot Deformity. Foot & ankle orthopaedics. 2019 Jul:4(3):2473011419849609. doi: 10.1177/2473011419849609. Epub 2019 Aug 19     [PubMed PMID: 35097328]


[30]

Jay RM, Din N. Correcting pediatric flatfoot with subtalar arthroereisis and gastrocnemius recession: a retrospective study. Foot & ankle specialist. 2013 Apr:6(2):101-7. doi: 10.1177/1938640012470714. Epub 2012 Dec 21     [PubMed PMID: 23263679]

Level 2 (mid-level) evidence

[31]

Vescio A, Testa G, Amico M, Lizzio C, Sapienza M, Pavone P, Pavone V. Arthroereisis in juvenile flexible flatfoot: Which device should we implant? A systematic review of literature published in the last 5 years. World journal of orthopedics. 2021 Jun 18:12(6):433-444. doi: 10.5312/wjo.v12.i6.433. Epub 2021 Jun 18     [PubMed PMID: 34189081]

Level 1 (high-level) evidence

[32]

Usuelli FG, Montrasio UA. The calcaneo-stop procedure. Foot and ankle clinics. 2012 Jun:17(2):183-94. doi: 10.1016/j.fcl.2012.03.001. Epub 2012 Apr 4     [PubMed PMID: 22541519]


[33]

Mazzotti A, Viglione V, Gerardi S, Artioli E, Rocca G, Faldini C. Subtalar arthroereisis post-operative management in children: A literature review. Foot (Edinburgh, Scotland). 2023 Sep:56():102037. doi: 10.1016/j.foot.2023.102037. Epub 2023 May 8     [PubMed PMID: 37167704]


[34]

van Ooij B, Vos CJ, Saouti R. Arthroereisis of the subtalar joint: an uncommon complication and literature review. The Journal of foot and ankle surgery : official publication of the American College of Foot and Ankle Surgeons. 2012 Jan-Feb:51(1):114-7. doi: 10.1053/j.jfas.2011.08.004. Epub 2011 Sep 28     [PubMed PMID: 21956005]


[35]

Scher DM, Bansal M, Handler-Matasar S, Bohne WH, Green DW. Extensive implant reaction in failed subtalar joint arthroereisis: report of two cases. HSS journal : the musculoskeletal journal of Hospital for Special Surgery. 2007 Sep:3(2):177-81. doi: 10.1007/s11420-007-9057-0. Epub     [PubMed PMID: 18751791]

Level 3 (low-level) evidence

[36]

Lui TH. Spontaneous subtalar fusion: an irreversible complication of subtalar arthroereisis. The Journal of foot and ankle surgery : official publication of the American College of Foot and Ankle Surgeons. 2014 Sep-Oct:53(5):652-6. doi: 10.1053/j.jfas.2014.04.005. Epub 2014 May 17     [PubMed PMID: 24846157]


[37]

Metcalfe SA, Bowling FL, Reeves ND. Subtalar joint arthroereisis in the management of pediatric flexible flatfoot: a critical review of the literature. Foot & ankle international. 2011 Dec:32(12):1127-39. doi: 10.3113/FAI.2011.1127. Epub     [PubMed PMID: 22381197]


[38]

Elmarghany M, Abd El-Ghaffar TM, Elgeushy A, Elzahed E, Hasanin Y, Knörr J. Is subtalar extra articular screw arthroereisis (SESA) reducing pain and restoring medial longitudinal arch in children with flexible flat foot? Journal of orthopaedics. 2020 Jul-Aug:20():147-153. doi: 10.1016/j.jor.2020.01.038. Epub 2020 Jan 28     [PubMed PMID: 32025139]


[39]

Smith C, Zaidi R, Bhamra J, Bridgens A, Wek C, Kokkinakis M. Subtalar arthroereisis for the treatment of the symptomatic paediatric flexible pes planus: a systematic review. EFORT open reviews. 2021 Feb:6(2):118-129. doi: 10.1302/2058-5241.6.200076. Epub 2021 Feb 1     [PubMed PMID: 33828855]

Level 1 (high-level) evidence

[40]

Saxena A, Via AG, Maffulli N, Chiu H. Subtalar Arthroereisis Implant Removal in Adults: A Prospective Study of 100 Patients. The Journal of foot and ankle surgery : official publication of the American College of Foot and Ankle Surgeons. 2016 May-Jun:55(3):500-3. doi: 10.1053/j.jfas.2015.12.005. Epub 2016 Feb 11     [PubMed PMID: 26874830]