J Korean Foot Ankle Soc.  2024 Dec;28(4):119-131. 10.14193/jkfas.2024.28.4.119.

Diagnosis and Treatment for Adult Flatfoot Deformity: Progressive Collapsing Foot Deformity

• Cho BK
• Lee Hs
• Park E
• Kim S

• KMID: 2562448
• DOI: http://doi.org/10.14193/jkfas.2024.28.4.119

Abstract

Adult-acquired flatfoot deformity is a progressive, debilitating condition characterized by three-dimensional deformities, including hindfoot valgus, forefoot abduction, forefoot or midfoot varus, peritalar subluxation, and ankle instability. A consensus group recently proposed a new nomenclature for this condition, termed progressive collapsing foot deformity (PCFD), and introduced a new classification system for PCFD. Moreover, with a vigorous investigation into PCFD and the widespread use of new diagnostic tools, including weight-bearing computed tomography, the understanding of PCFD has improved considerably. As the understanding of the various components of PCFD has deepened, a range of treatment options, from conservative management to osteotomy and arthrodesis, have been reported to correct each component. Therefore, this paper provides an overview of the classification systems, diagnostic methods, and various treatment approaches for PCFD.

Keyword

Foot; Flatfoot; Deformities; Diagnosis; Osteotomy

Figure

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  Figure 1 Weight bearing foot anteroposterior radiograph showing talonavicular coverage angle (*) and talonavicular uncoverage percent (**).

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  Figure 2 Weight bearing foot lateral radiograph showing talo-1st metatarsal angle.

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  Figure 3 Weight bearing foot lateral radiograph showing plantar gapping of naviculocuneiform joint (*) and tarsometatarsal joint (**). Sinus tarsi impingement (black arrow) and bony sclerosis around sinus tarsi (white arrow).

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  Figure 4 Weight bearing ankle anteroposterior radiograph showing valgus talar tilt and subfibular impingement (*).

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  Figure 5 Hindfoot alignment view showing hindfoot alignment angle (*) and hindfoot moment arm (**).

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  Figure 6 Weight bearing foot computed tomography showing hindfoot valgus (*) and sinus tarsi impingement (**). Medial column instability on talonavicular joint (black arrow) and tarsometatarsal joint with plantar gapping (white arrow).

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  Figure 7 Foot and ankle offset (FAO). First metatarsal head weight bearing point M1, fifth metatarsal head weight bearing point M5, calcaneus weight bearing point C, and central apex of the talar dome T are marked. “a” refers to the distance from C to the midpoint between M1 and M5, and “b” indicates the distance from T to line “a” FAO (%)=b/a.

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  Figure 8 Photograph of clinical forefoot varus deformity.

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  Figure 9 Medial displacement calcaneal osteotomy to correct hindfoot valgus.

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  Figure 10 Lateral column lengthening to fix forefoot abduction.

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  Figure 11 Preoperative and postoperative plain radiograph of the weight bearing foot anteroposterior, lateral, and hindfoot views of a 20-year-old female patient with a unilateral flatfoot deformity who was performed double calcaneal osteotomy.

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  Figure 12 Pre- and post-operative plain weight bearing foot anteroposterior, lateral, and hindfoot radiographs of a 74-year-old female patient who was underwent subtalar repositional arthrodesis and first metatarsal plantar closing wedge osteotomy.

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  Figure 13 Weight bearing ankle anteroposterior radiograph showing valgus talar tilt after hindfoot arthrodesis (*).

Reference

Henry JK., Shakked R., Ellis SJ. 2019. Adult-acquired flatfoot deformity. Foot Ankle Orthop. 4:2473011418820847. doi: 10.1177/2473011418820847. DOI: 10.1177/2473011418820847. PMID: 35097314. PMCID: PMC8696898.

Smyth NA., Aiyer AA., Kaplan JR., Carmody CA., Kadakia AR. 2017. Adult-acquired flatfoot deformity. Eur J Orthop Surg Traumatol. 27:433–9. doi: 10.1007/s00590-017-1945-5. DOI: 10.1007/s00590-017-1945-5. PMID: 28324203.

Abousayed MM., Alley MC., Shakked R., Rosenbaum AJ. 2017. Adult-acquired flatfoot deformity: etiology, diagnosis, and management. JBJS Rev. 5:e7. doi: 10.2106/JBJS.RVW.16.00116. DOI: 10.2106/JBJS.RVW.16.00116. PMID: 28806265.

Johnson KA., Strom DE. 1989. Tibialis posterior tendon dysfunction. Clin Orthop Relat Res. 196–206. DOI: 10.1097/00003086-198902000-00022.

Bluman EM., Title CI., Myerson MS. 2007. Posterior tibial tendon rupture: a refined classification system. Foot Ankle Clin. 12:233–49. vdoi: 10.1016/j.fcl.2007.03.003. DOI: 10.1016/j.fcl.2007.03.003. PMID: 17561198.

Myerson MS., Thordarson DB., Johnson JE., Hintermann B., Sangeorzan BJ., Deland JT, et al. 2020. Classification and nomenclature: progressive collapsing foot deformity. Foot Ankle Int. 41:1271–6. doi: 10.1177/1071100720950722. DOI: 10.1177/1071100720950722. PMID: 32856474.

Toullec E. 2015. Adult flatfoot. Orthop Traumatol Surg Res. 101:S11–7. doi: 10.1016/j.otsr.2014.07.030. DOI: 10.1016/j.otsr.2014.07.030. PMID: 25595429.

Saltzman CL., el-Khoury GY. 1995. The hindfoot alignment view. Foot Ankle Int. 16:572–6. doi: 10.1177/107110079501600911. DOI: 10.1177/107110079501600911. PMID: 8563927.

de Cesar Netto C., Myerson MS., Day J., Ellis SJ., Hintermann B., Johnson JE, et al. 2020. Consensus for the use of weightbearing CT in the assessment of progressive collapsing foot deformity. Foot Ankle Int. 41:1277–82. doi: 10.1177/1071100720950734. DOI: 10.1177/1071100720950734. PMID: 32851880.

Williamson ER., Chan JY., Burket JC., Deland JT., Ellis SJ. 2015. New radiographic parameter assessing hindfoot alignment in stage II adult-acquired flatfoot deformity. Foot Ankle Int. 36:417–23. doi: 10.1177/1071100714558846. DOI: 10.1177/1071100714558846. PMID: 25380772.

Lôbo CFT., Pires EA., Bordalo-Rodrigues M., de Cesar Netto C., Godoy-Santos AL. 2022. Imaging of progressive collapsing foot deformity with emphasis on the role of weightbearing cone beam CT. Skeletal Radiol. 51:1127–41. doi: 10.1007/s00256-021-03942-1. DOI: 10.1007/s00256-021-03942-1. PMID: 34693455.

de Cesar Netto C., Shakoor D., Roberts L., Chinanuvathana A., Mousavian A., Lintz F, et al. 2019. ; Weight Bearing CT International Study Group. Hindfoot alignment of adult acquired flatfoot deformity: a comparison of clinical assessment and weightbearing cone beam CT examinations. Foot Ankle Surg. 25:790–7. doi: 10.1016/j.fas.2018.10.008. DOI: 10.1016/j.fas.2018.10.008. PMID: 30455094.

de Cesar Netto C., Shakoor D., Dein EJ., Zhang H., Thawait GK., Richter M, et al. 2019. ; Weightbearing CT International Study Group. Influence of investigator experience on reliability of adult acquired flatfoot deformity measurements using weightbearing computed tomography. Foot Ankle Surg. 25:495–502. doi: 10.1016/j.fas.2018.03.001. DOI: 10.1016/j.fas.2018.03.001. PMID: 30321961.

de Cesar Netto C., Schon LC., Thawait GK., da Fonseca LF., Chinanuvathana A., Zbijewski WB, et al. 2017. Flexible adult acquired flatfoot deformity: comparison between weight-bearing and non-weight-bearing measurements using cone-beam computed tomography. J Bone Joint Surg Am. 99:e98. doi: 10.2106/JBJS.16.01366. DOI: 10.2106/JBJS.16.01366. PMID: 28926392.

Apostle KL., Coleman NW., Sangeorzan BJ. 2014. Subtalar joint axis in patients with symptomatic peritalar subluxation compared to normal controls. Foot Ankle Int. 35:1153–8. doi: 10.1177/1071100714546549. DOI: 10.1177/1071100714546549. PMID: 25104749.

Day J, de Cesar Netto C, Nishikawa DRC, Garfinkel J, Roney A, J O'Malley M, et al. 2020. Three-dimensional biometric weightbearing CT evaluation of the operative treatment of adult-acquired flatfoot deformity. Foot Ankle Int. 41:930–6. doi: 10.1177/1071100720925423. DOI: 10.1177/1071100720925423. PMID: 32506953.

de Cesar Netto C., Bang K., Mansur NS., Garfinkel JH., Bernasconi A., Lintz F, et al. 2020. Multiplanar semiautomatic assessment of foot and ankle offset in adult acquired flatfoot deformity. Foot Ankle Int. 41:839–48. doi: 10.1177/1071100720920274. DOI: 10.1177/1071100720920274. PMID: 32441540.

Haleem AM., Pavlov H., Bogner E., Sofka C., Deland JT., Ellis SJ. 2014. Comparison of deformity with respect to the talus in patients with posterior tibial tendon dysfunction and controls using multiplanar weight-bearing imaging or conventional radiography. J Bone Joint Surg Am. 96:e63. doi: 10.2106/JBJS.L.01205. DOI: 10.2106/JBJS.L.01205. PMID: 24740671.

Kunas GC., Probasco W., Haleem AM., Burket JC., Williamson ERC., Ellis SJ. 2018. Evaluation of peritalar subluxation in adult acquired flatfoot deformity using computed tomography and weightbearing multiplanar imaging. Foot Ankle Surg. 24:495–500. doi: 10.1016/j.fas.2017.05.010. DOI: 10.1016/j.fas.2017.05.010. PMID: 29409191.

Evans EL., Catanzariti AR. 2014. Forefoot supinatus. Clin Podiatr Med Surg. 31:405–13. doi: 10.1016/j.cpm.2014.03.009. DOI: 10.1016/j.cpm.2014.03.009. PMID: 24980930.

Lee HY., Barbachan Mansur NS., Lalevée M., Dibbern KN., Myerson MS., Ellis SJ, et al. 2022. ; Progressive Collapsing Foot Deformity Consensus Group. Intra- and interobserver reliability of the new classification system of progressive collapsing foot deformity. Foot Ankle Int. 43:582–9. doi: 10.1177/10711007211058154. DOI: 10.1177/10711007211058154. PMID: 34852647.

Li S., Zhu M., Gu W., Hamati M., Hunt KJ., de Cesar Netto C, et al. 2022. Diagnostic accuracy of the progressive collapsing foot deformity (PCFD) classification. Foot Ankle Int. 43:800–9. doi: 10.1177/10711007221078000. DOI: 10.1177/10711007221078000. PMID: 35301895.

Lalevée M., Barbachan Mansur NS., Lee HY., Ehret A., Tazegul T., de Carvalho KAM, et al. 2023. A comparison between the Bluman et al. and the progressive collapsing foot deformity classifications for flatfeet assessment. Arch Orthop Trauma Surg. 143:1331–9. doi: 10.1007/s00402-021-04279-z. DOI: 10.1007/s00402-021-04279-z. PMID: 34859296.

Chao W., Wapner KL., Lee TH., Adams J., Hecht PJ. 1996. Nonoperative management of posterior tibial tendon dysfunction. Foot Ankle Int. 17:736–41. doi: 10.1177/107110079601701204. DOI: 10.1177/107110079601701204. PMID: 8973895.

Augustin JF., Lin SS., Berberian WS., Johnson JE. 2003. Nonoperative treatment of adult acquired flat foot with the Arizona brace. Foot Ankle Clin. 8:491–502. doi: 10.1016/s1083-7515(03)00036-6. DOI: 10.1016/S1083-7515(03)00036-6. PMID: 14560901.

Alvarez RG., Marini A., Schmitt C., Saltzman CL. 2006. Stage I and II posterior tibial tendon dysfunction treated by a structured nonoperative management protocol: an orthosis and exercise program. Foot Ankle Int. 27:2–8. doi: 10.1177/107110070602700102. DOI: 10.1177/107110070602700102. PMID: 16442022.

Kulig K., Reischl SF., Pomrantz AB., Burnfield JM., Mais-Requejo S., Thordarson DB, et al. 2009. Nonsurgical management of posterior tibial tendon dysfunction with orthoses and resistive exercise: a randomized controlled trial. Phys Ther. 89:26–37. doi: 10.2522/ptj.20070242. DOI: 10.2522/ptj.20070242. PMID: 19022863.

Pell RF 4th., Myerson MS., Schon LC. 2000. Clinical outcome after primary triple arthrodesis. J Bone Joint Surg Am. 82:47–57. doi: 10.2106/00004623-200001000-00006. DOI: 10.2106/00004623-200001000-00006. PMID: 10653083.

Hintermann B., Deland JT., de Cesar Netto C., Ellis SJ., Johnson JE., Myerson MS, et al. 2020. Consensus on indications for isolated subtalar joint fusion and naviculocuneiform fusions for progressive collapsing foot deformity. Foot Ankle Int. 41:1295–8. doi: 10.1177/1071100720950738. DOI: 10.1177/1071100720950738. PMID: 32851856.

Fadle AA., El-Adly W., Attia AK., Mohamed MM., Mohamadean A., Osman AE. 2021. Double versus triple arthrodesis for adult-acquired flatfoot deformity due to stage III posterior tibial tendon insufficiency: a prospective comparative study of two cohorts. Int Orthop. 45:2219–29. doi: 10.1007/s00264-021-05041-1. DOI: 10.1007/s00264-021-05041-1. PMID: 33895880. PMCID: PMC8494666.

Burns PR., Powers NS. 2023. Double versus triple arthrodesis for flatfoot deformity: when, why, and how? Clin Podiatr Med Surg. 40:315–32. doi: 10.1016/j.cpm.2022.11.009. DOI: 10.1016/j.cpm.2022.11.009. PMID: 36841582.

Chadwick C., Whitehouse SL., Saxby TS. 2015. Long-term follow-up of flexor digitorum longus transfer and calcaneal osteotomy for stage II posterior tibial tendon dysfunction. Bone Joint J. 97:346–52. doi: 10.1302/0301-620X.97B3.34386. DOI: 10.1302/0301-620X.97B3.34386. PMID: 25737518.

Niki H., Hirano T., Okada H., Beppu M. 2012. Outcome of medial displacement calcaneal osteotomy for correction of adult-acquired flatfoot. Foot Ankle Int. 33:940–6. doi: 10.3113/FAI.2012.0940. DOI: 10.3113/FAI.2012.0940. PMID: 23131439.

Smith BA., Adelaar RS., Wayne JS. 2017. Patient specific computational models to optimize surgical correction for flatfoot deformity. J Orthop Res. 35:1523–31. doi: 10.1002/jor.23399. DOI: 10.1002/jor.23399. PMID: 27556250.

Bolt PM., Coy S., Toolan BC. 2007. A comparison of lateral column lengthening and medial translational osteotomy of the calcaneus for the reconstruction of adult acquired flatfoot. Foot Ankle Int. 28:1115–23. doi: 10.3113/FAI.2007.1115. DOI: 10.3113/FAI.2007.1115. PMID: 18021579.

Osman AE., El-Gafary KA., Khalifa AA., El-Adly W., Fadle AA., Abubeih H. 2021. Medial displacement calcaneal osteotomy versus lateral column lengthening to treat stage II tibialis posterior tendon dysfunction, a prospective randomized controlled study. Foot (Edinb). 47:101798. doi: 10.1016/j.foot.2021.101798. DOI: 10.1016/j.foot.2021.101798. PMID: 33957531.

Conti MS., Ellis SJ., Chan JY., Do HT., Deland JT. 2015. Optimal position of the heel following reconstruction of the stage II adult-acquired flatfoot deformity. Foot Ankle Int. 36:919–27. doi: 10.1177/1071100715576918. DOI: 10.1177/1071100715576918. PMID: 25948692. PMCID: PMC4747098.

Crawford AW., Haleem AM. 2021. I am afraid of lateral column lengthening. Should I be? Foot Ankle Clin. 26:523–38. doi: 10.1016/j.fcl.2021.06.003. DOI: 10.1016/j.fcl.2021.06.003. PMID: 34332733.

Dinucci KR., Christensen JC., Dinucci KA. 2004. Biomechanical consequences of lateral column lengthening of the calcaneus: part I. long plantar ligament strain. J Foot Ankle Surg. 43:10–5. doi: 10.1053/j.jfas.2003.11.013. DOI: 10.1053/j.jfas.2003.11.013. PMID: 14752758.

Oh I., Imhauser C., Choi D., Williams B., Ellis S., Deland J. 2013. Sensitivity of plantar pressure and talonavicular alignment to lateral column lengthening in flatfoot reconstruction. J Bone Joint Surg Am. 95:1094–100. doi: 10.2106/JBJS.K.01032. DOI: 10.2106/JBJS.K.01032. PMID: 23783206. PMCID: PMC6948803.

Conti MS., Chan JY., Do HT., Ellis SJ., Deland JT. 2015. Correlation of postoperative midfoot position with outcome following reconstruction of the stage II adult acquired flatfoot deformity. Foot Ankle Int. 36:239–47. doi: 10.1177/1071100714564217. DOI: 10.1177/1071100714564217. PMID: 25589542. PMCID: PMC4748705.

Modha RK., Kilmartin TE. 2021. Lateral column lengthening for flexible adult acquired flatfoot: systematic review and meta-analysis. J Foot Ankle Surg. 60:1254–69. doi: 10.1053/j.jfas.2021.02.015. DOI: 10.1053/j.jfas.2021.02.015. PMID: 34253434.

Chan JY., Greenfield ST., Soukup DS., Do HT., Deland JT., Ellis SJ. 2015. Contribution of lateral column lengthening to correction of forefoot abduction in stage IIb adult acquired flatfoot deformity reconstruction. Foot Ankle Int. 36:1400–11. doi: 10.1177/1071100715596607. DOI: 10.1177/1071100715596607. PMID: 26216884.

Grunander TR., Thordarson DB. 2012. Results of calcaneocuboid distraction arthrodesis. Foot Ankle Surg. 18:15–8. doi: 10.1016/j.fas.2011.01.004. DOI: 10.1016/j.fas.2011.01.004. PMID: 22325997.

Haeseker GA., Mureau MA., Faber FW. 2010. Lateral column lengthening for acquired adult flatfoot deformity caused by posterior tibial tendon dysfunction stage II: a retrospective comparison of calcaneus osteotomy with calcaneocuboid distraction arthrodesis. J Foot Ankle Surg. 49:380–4. doi: 10.1053/j.jfas.2010.04.023. DOI: 10.1053/j.jfas.2010.04.023. PMID: 20610204.

Attia E., Heldt B., Roepe IG., Shenava VR., Hill JF. 2021. Does the stabilization of the calcaneocuboid joint with Steinmann pin in Evans osteotomy affect its incidence of arthritis? Foot (Edinb). 49:101846. doi: 10.1016/j.foot.2021.101846. DOI: 10.1016/j.foot.2021.101846. PMID: 34560432.

Siebert M., Hedrick BN., Zide JR., Thomas DM., Shivers C., Pierce WA, et al. 2021. Do we really need to worry about calcaneocuboid subluxation during lateral column lengthening for planovalgus foot deformity? J Pediatr Orthop. 41:e246–51. doi: 10.1097/BPO.0000000000001752. DOI: 10.1097/BPO.0000000000001752. PMID: 33417392.

Adams SB Jr., Simpson AW., Pugh LI., Stasikelis PJ. 2009. Calcaneocuboid joint subluxation after calcaneal lengthening for planovalgus foot deformity in children with cerebral palsy. J Pediatr Orthop. 29:170–4. doi: 10.1097/BPO.0b013e3181982c33. DOI: 10.1097/BPO.0b013e3181982c33. PMID: 19352243.

Bae K., Kwak YH., Kang MS., Huser AJ., Kim D., Kim G, et al. 2024. Postoperative calcaneocuboid joint subluxation and midtarsal joint changes in pediatric idiopathic flexible flatfoot treated with calcaneal lengthening osteotomy: a midterm follow-up study. Foot Ankle Int. 45:1059–67. doi: 10.1177/10711007241256638. DOI: 10.1177/10711007241256638. PMID: 39192664.

Ahn JY., Lee HS., Kim CH., Yang JP., Park SS. 2014. Calcaneocuboid joint subluxation after the calcaneal lengthening procedure in children. Foot Ankle Int. 35:677–82. doi: 10.1177/1071100714528494. DOI: 10.1177/1071100714528494. PMID: 24677218.

Kim S., Cho BK., Choi Y., Ahn J., Lee HS. 2024. Clinical and radiological outcomes of flexible flatfoot correction with double calcaneal osteotomy. J Orthop Surg Res. 19:627. doi: 10.1186/s13018-024-05106-y. DOI: 10.1186/s13018-024-05106-y. PMID: 39367451. PMCID: PMC11453064.

Basioni Y., El-Ganainy AR., El-Hawary A. 2011. Double calcaneal osteotomy and percutaneous tenoplasty for adequate arch restoration in adult flexible flat foot. Int Orthop. 35:47–51. doi: 10.1007/s00264-010-1071-z. DOI: 10.1007/s00264-010-1071-z. PMID: 20556379. PMCID: PMC3014475.

Xu Y., Cao YX., Li XC., Zhu Y., Xu XY. 2017. Double calcaneal osteotomy for severe adolescent flexible flatfoot reconstruction. J Orthop Surg Res. 12:153. doi: 10.1186/s13018-017-0655-3. DOI: 10.1186/s13018-017-0655-3. PMID: 29041945. PMCID: PMC5645836.

Frankel JP., Turf RM., Kuzmicki LM. 1995. Double calcaneal osteotomy in the treatment of posterior tibial tendon dysfunction. J Foot Ankle Surg. 34:254–61. doi: 10.1016/S1067-2516(09)80056-2. DOI: 10.1016/S1067-2516(09)80056-2. PMID: 7550188.

Zanolli DH., Glisson RR., Nunley JA 2nd., Easley ME. 2014. Biomechanical assessment of flexible flatfoot correction: comparison of techniques in a cadaver model. J Bone Joint Surg Am. 96:e45. doi: 10.2106/JBJS.L.00258. DOI: 10.2106/JBJS.L.00258. PMID: 24647512.

Greisberg J., Assal M., Hansen ST Jr., Sangeorzan BJ. 2005. Isolated medial column stabilization improves alignment in adult-acquired flatfoot. Clin Orthop Relat Res. 197–202. doi: 10.1097/01.blo.0000157658.17056.46. DOI: 10.1097/01.blo.0000157658.17056.46. PMID: 15930939.

Johnson JE., Sangeorzan BJ., de Cesar Netto C., Deland JT., Ellis SJ., Hintermann B, et al. 2020. Consensus on indications for medial cuneiform opening wedge (cotton) osteotomy in the treatment of progressive collapsing foot deformity. Foot Ankle Int. 41:1289–91. doi: 10.1177/1071100720950739. DOI: 10.1177/1071100720950739. PMID: 32856482.

Ling JS., Ross KA., Hannon CP., Egan C., Smyth NA., Hogan MV, et al. 2013. A plantar closing wedge osteotomy of the medial cuneiform for residual forefoot supination in flatfoot reconstruction. Foot Ankle Int. 34:1221–6. doi: 10.1177/1071100713487726. DOI: 10.1177/1071100713487726. PMID: 23624906.

Hirose CB., Johnson JE. 2004. Plantarflexion opening wedge medial cuneiform osteotomy for correction of fixed forefoot varus associated with flatfoot deformity. Foot Ankle Int. 25:568–74. doi: 10.1177/107110070402500810. DOI: 10.1177/107110070402500810. PMID: 15363379.

Vacketta VG., Jones JM., Catanzariti AR. 2022. Radiographic analysis and clinical efficacy of hindfoot arthrodesis with versus without cotton osteotomy in stage III adult acquired flatfoot deformity. J Foot Ankle Surg. 61:879–85. doi: 10.1053/j.jfas.2021.12.012. DOI: 10.1053/j.jfas.2021.12.012. PMID: 34987007.

Lutz M., Myerson M. 2011. Radiographic analysis of an opening wedge osteotomy of the medial cuneiform. Foot Ankle Int. 32:278–87. doi: 10.3113/FAI.2011.0278. DOI: 10.3113/FAI.2011.0278. PMID: 21477547.

Steiner CS., Gilgen A., Zwicky L., Schweizer C., Ruiz R., Hintermann B. 2019. Combined subtalar and naviculocuneiform fusion for treating adult acquired flatfoot deformity with medial arch collapse at the level of the naviculocuneiform joint. Foot Ankle Int. 40:42–7. doi: 10.1177/1071100718800295. DOI: 10.1177/1071100718800295. PMID: 30317867.

McCormick JJ., Johnson JE. 2012. Medial column procedures in the correction of adult acquired flatfoot deformity. Foot Ankle Clin. 17:283–98. doi: 10.1016/j.fcl.2012.03.003. DOI: 10.1016/j.fcl.2012.03.003. PMID: 22541526.

Walters JL., Mendicino SS. 2014. Flexible adult flatfoot: soft tissue procedures. Clin Podiatr Med Surg. 31:349–55. doi: 10.1016/j.cpm.2014.03.006. DOI: 10.1016/j.cpm.2014.03.006. PMID: 24980925.

DeVries JG., DeCarbo WT., Scott RT., Bussewitz B., Thompson M., Hyer CF. 2022. Soft tissue reconstruction and osteotomies for pes planovalgus correction. Clin Podiatr Med Surg. 39:207–31. doi: 10.1016/j.cpm.2021.11.010. DOI: 10.1016/j.cpm.2021.11.010. PMID: 35365324.

Spratley EM., Arnold JM., Owen JR., Glezos CD., Adelaar RS., Wayne JS. 2013. Plantar forces in flexor hallucis longus versus flexor digitorum longus transfer in adult acquired flatfoot deformity. Foot Ankle Int. 34:1286–93. doi: 10.1177/1071100713487724. DOI: 10.1177/1071100713487724. PMID: 23613328.

Aronow MS. 2012. Tendon transfer options in managing the adult flexible flatfoot. Foot Ankle Clin. 17:205–26. viidoi: 10.1016/j.fcl.2012.02.001. DOI: 10.1016/j.fcl.2012.02.001. PMID: 22541521.

Den Hartog BD. 2001. Flexor digitorum longus transfer with medial displacement calcaneal osteotomy. Biomechanical rationale. Foot Ankle Clin. 6:67–76. vidoi: 10.1016/s1083-7515(03)00079-2. DOI: 10.1016/S1083-7515(03)00079-2. PMID: 11385928.

Lin JS., Myerson MS. 2011. The management of complications following the treatment of flatfoot deformity. Instr Course Lect. 60:321–34.

Nery C., Baumfeld D. 2021. Current trends in treatment of injuries to spring ligament. Foot Ankle Clin. 26:345–59. doi: 10.1016/j.fcl.2021.03.008. DOI: 10.1016/j.fcl.2021.03.008. PMID: 33990257.

Deland JT., Ellis SJ., Day J., de Cesar Netto C., Hintermann B., Myerson MS, et al. 2020. Indications for deltoid and spring ligament reconstruction in progressive collapsing foot deformity. Foot Ankle Int. 41:1302–6. doi: 10.1177/1071100720950742. DOI: 10.1177/1071100720950742. PMID: 32851857.

Hatic SO 2nd., Philbin TM. 2012. Management of the recurrent deformity in a flexible foot following failure of tendon transfer: is arthrodesis necessary? Foot Ankle Clin. 17:299–307. doi: 10.1016/j.fcl.2012.03.007. DOI: 10.1016/j.fcl.2012.03.007. PMID: 22541527.

Ahmad J., Pedowitz D. 2012. Management of the rigid arthritic flatfoot in adults: triple arthrodesis. Foot Ankle Clin. 17:309–22. doi: 10.1016/j.fcl.2012.03.008. DOI: 10.1016/j.fcl.2012.03.008. PMID: 22541528.

Gentchos CE., Anderson JG., Bohay DR. 2012. Management of the rigid arthritic flatfoot in the adults: alternatives to triple arthrodesis. Foot Ankle Clin. 17:323–35. doi: 10.1016/j.fcl.2012.03.009. DOI: 10.1016/j.fcl.2012.03.009. PMID: 22541529.

Astion DJ., Deland JT., Otis JC., Kenneally S. 1997. Motion of the hindfoot after simulated arthrodesis. J Bone Joint Surg Am. 79:241–6. doi: 10.2106/00004623-199702000-00012. DOI: 10.2106/00004623-199702000-00012. PMID: 9052546.

Taylor R., Sammarco VJ. 2012. Minimizing the role of fusion in the rigid flatfoot. Foot Ankle Clin. 17:337–49. doi: 10.1016/j.fcl.2012.03.010. DOI: 10.1016/j.fcl.2012.03.010. PMID: 22541530.

Conti MS., Ellis SJ. 2021. Spare the talonavicular joint! The role of isolated subtalar joint fusion in the treatment of progressive collapsing foot deformity. Foot Ankle Clin. 26:591–607. doi: 10.1016/j.fcl.2021.05.005. DOI: 10.1016/j.fcl.2021.05.005. PMID: 34332737.

Kitaoka HB., Patzer GL. 1997. Subtalar arthrodesis for posterior tibial tendon dysfunction and pes planus. Clin Orthop Relat Res. 187–94. DOI: 10.1097/00003086-199712000-00027.

Johnson JE., Cohen BE., DiGiovanni BF., Lamdan R. 2000. Subtalar arthrodesis with flexor digitorum longus transfer and spring ligament repair for treatment of posterior tibial tendon insufficiency. Foot Ankle Int. 21:722–9. doi: 10.1177/107110070002100902. DOI: 10.1177/107110070002100902. PMID: 11023218.

Stephens HM., Walling AK., Solmen JD., Tankson CJ. 1999. Subtalar repositional arthrodesis for adult acquired flatfoot. Clin Orthop Relat Res. 69–73. doi: 10.1097/00003086-199908000-00009. DOI: 10.1097/00003086-199908000-00009. PMID: 10627688.

Mangone PG., Fleming LL., Fleming SS., Hedrick MR., Seiler JG 3rd., Bailey E. 1997. Treatment of acquired adult planovalgus deformities with subtalar fusion. Clin Orthop Relat Res. 106–12. DOI: 10.1097/00003086-199708000-00017.

Kim S., Park E., Cho BK., Doh CH., Choi Y., Lee HS. 2024. Isolated subtalar repositional arthrodesis compared with triple arthrodesis for the treatment of progressive collapsing foot deformity. J Foot Ankle Surg. 63:443–9. doi: 10.1053/j.jfas.2024.02.002. DOI: 10.1053/j.jfas.2024.02.002. PMID: 38447799.

Song SJ., Lee S., O'Malley MJ., Otis JC., Sung IH., Deland JT. 2000. Deltoid ligament strain after correction of acquired flatfoot deformity by triple arthrodesis. Foot Ankle Int. 21:573–7. doi: 10.1177/107110070002100708. DOI: 10.1177/107110070002100708. PMID: 10919623.

Friedman MA., Draganich LF., Toolan B., Brage ME. 2001. The effects of adult acquired flatfoot deformity on tibiotalar joint contact characteristics. Foot Ankle Int. 22:241–6. doi: 10.1177/107110070102200312. DOI: 10.1177/107110070102200312. PMID: 11310867.

Röhm J., Zwicky L., Horn Lang T., Salentiny Y., Hintermann B., Knupp M. 2015. Mid- to long-term outcome of 96 corrective hindfoot fusions in 84 patients with rigid flatfoot deformity. Bone Joint J. 97:668–74. doi: 10.1302/0301-620X.97B5.35063. DOI: 10.1302/0301-620X.97B5.35063. PMID: 25922462.

Hyer CF., Galli MM., Scott RT., Bussewitz B., Berlet GC. 2014. Ankle valgus after hindfoot arthrodesis: a radiographic and chart comparison of the medial double and triple arthrodeses. J Foot Ankle Surg. 53:55–8. doi: 10.1053/j.jfas.2013.02.018. DOI: 10.1053/j.jfas.2013.02.018. PMID: 23910739.

Miniaci-Coxhead SL., Weisenthal B., Ketz JP., Flemister AS. 2017. Incidence and radiographic predictors of valgus tibiotalar tilt after hindfoot fusion. Foot Ankle Int. 38:519–25. doi: 10.1177/1071100717690439. DOI: 10.1177/1071100717690439. PMID: 28142248.