Sinus Tarsi Implant as an Adjuvant Procedure to Medial Displacement Calcaneal Osteotomy in the Treatment of Mobile Adult Acquired Flatfoot Deformity

NCT06211504 | Recruiting Phase 4 FDA Device

• 1 other identifier: 2023-02892-01
• Study Type: interventional
• Target: 130
• Locations: 1 country
• Sites: 10

Brief Summary

Background: Adult acquired flatfoot deformity (AAFD) is a deformity of the foot which leads to pain and an altered gait pattern. There are several different surgical interventions available for treatment of AAFD. One of the most common treatments for mobile AAFD is medial displacement calcaneal osteotomy (MDCO) with or without adjuvant soft tissue procedures. However, the medial displacement of the calcaneus only aims to correct the deformity in one plane despite AAFD being a deformity of three planes with hypereversion of the calcaneus, anterior translation of the talus over the calcaneus and tilting/drop of the calcaneal head. Because of these multiple forces, the healing of MDCO in the intended position can sometimes be hard to achieve and medial soft tissue is still stressed leading to recurring deformity. The investigators believe that adjuvant insertion of a sinus tarsi implant (STI) could work as an internal splint, protecting soft tissue procedures on the medial side, reversing anterior translation of the talus, opposing calcaneus eversion, and lifting talar head. This additional procedure will create a better correction of the deformity with enhanced appearance of the foot and better long-term functional results. Methods: This is a multi-center randomized controlled trial designed to assess the efficacy of STI as an adjuvant procedure to MDCO in patients with mobile AAFD (Stage II). Patients aged 16 to 75 years, referred to one of the orthopedic centers involved in this study, will be invited to participate if they fulfil the trials eligibility criteria. In total, 130 patients who provide informed consent will be randomized to either MDCO with STI or MDCO without STI (65 patients in each group). The included patients will be clinically and radiographically examined. They will also fill out a form before surgery and 4-5 months, 1 year and 2 years postoperatively. The form will include Self-Reported Foot and Ankle Score (SEFAS) and Euro-QoL 5 Dimensions (EQ-5D). The trials primary outcome will be change in Meary's angle. Secondary outcomes include additional radiographic changes, change in SEFAS score, EQ-5D index, pain according to visual analog scale (VAS), satisfaction assessment, clinical outcome measures, the length of postoperative sick-leave and rate of complications. Discussion: This is the first randomized controlled trial assessing the efficacy of a sinus tarsi implant as an adjuvant procedure to MDCO.

Conditions

Acquired Adult Flatfoot Deformity; Flat Foot; Flexible Flatfoot

Keywords

AAFD; RCT; clinical trial; surgical intervention; arthroereisis; sinus tarsi implant

Outcome Measures

Primary Outcomes (1)

• Meary's angle

  Change in degrees of Meary's angle

  From baseline/preoperatively (max 6 months preoperatively) to 12 months postoperatively

Secondary Outcomes (20)

• Meary's angle

  From baseline/preoperatively (max 6 months preoperatively) to 4-5 and 24 months postoperatively

• Calcaneal inclination angle

  From baseline/preoperatively (max 6 months preoperatively) to 4-5, 12, and 24 months postoperatively

• Talar declination angle

  From baseline/preoperatively (max 6 months preoperatively) to 4-5, 12, and 24 months postoperatively

• Talar-2nd metatarsal angle

  From baseline/preoperatively (max 6 months preoperatively) to 4-5, 12, and 24 months postoperatively

• Talar coverage angle

  From baseline/preoperatively (max 6 months preoperatively) to 4-5, 12, and 24 months postoperatively

Study Arms (2)

MDCO without STI

ACTIVE COMPARATOR

1. For patients with preoperative gastrocnemius-soleus complex tightness, defined as a preoperative dorsal extension of the ankle less than 5 degrees, with the knee completely extended, a Strayer´s procedure will be performed before the other procedures. 2. MDCO will be performed where the distal aspect of the calcaneus is separated from the proximal aspects, slided medially and fixed with two screws. 3. After the MDCO, FDL will be transferred to the navicular bone. 4. The spring ligament will be assessed. If ruptured, it will be reconstructed. If not ruptured, it will be tightened. 5. A plantarflexing open wedge osteotomy of the medial cuneiform (Cotton osteotomy) will be performed if pre-/perioperative findings indicate it.

Procedure: Conventional surgery

MDCO with STI

EXPERIMENTAL

1. In patients with preoperative gastrocnemius-soleus complex tightness, defined as a preoperative dorsal extension of the ankle less than 5 degrees, with the knee completely extended, a Strayer´s procedure will be performed before the other procedures. 2. Thereafter, an STI (ProStop® Arthroereisis Subtalar Implant, Arthrex GmbH, Munich, Germany) will be inserted into the sinus tarsi. 3. MDCO will be performed where the distal aspect of the calcaneus is separated from the proximal aspects, slided medially and fixed with two screws. 4. After the MDCO, FDL will be transferred to the navicular bone. 5. The spring ligament will be assessed. If ruptured, it will be reconstructed. If not ruptured, it will be tightened. 6. A plantarflexing open wedge osteotomy of the medial cuneiform (Cotton osteotomy) will be performed if pre-/perioperative findings indicate it.

Device: ProStop, sinus tarsi implant (STI); Procedure: Conventional surgery

Interventions

ProStop, sinus tarsi implant (STI) DEVICE

Insertion of a sinus tarsi implant (ProStop from Arthrex) in sinus tarsi

Also known as: arthroereisis

MDCO with STI

Conventional surgery PROCEDURE

MDCO - medial displacement calcaneal osteotomy FDL transfer - flexor digitorum longus tendon transfer to the navicular bone Spring ligament repair - reconstruction of the spring ligament Strayer's procedure - gastrocnemius recession (if necessary) Cotton osteotomy - medial cuneiform opening wedge osteotomy (if necessary)

MDCO with STI; MDCO without STI

Eligibility Criteria

• Age: 16 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

• Patients with AAFD stage II, in whom the talonavicular uncoverage is not considered by the treating surgeon to require an additional lateral column lengthening
• Age 16-75 years, either sex
• Failed non-surgical treatment including 3 months of physiotherapy

You may not qualify if:

• Previous ipsilateral surgery for AAFD
• General hypermobility (Beighton score \> 6)
• Osteoarthritis in the hindfoot joints, ankle joint or first tarsometatarsal joint
• Rheumatoid arthritis
• Inability to answer patient-reported outcome measures (PROMs) due to language difficulties or cognitive disorder
• Current smoker
• Current pregnancy
• Severe medical illness
• Known abuse of drugs and/or alcohol
• Previous ipsilateral hindfoot fracture including Lisfranc injury

Sponsors & Collaborators

• Region Skane: lead

Study Sites (10)

Department of Orthopedics - Hässleholm Hospital

Hässleholm, Skåne County, 281 38, Sweden

RECRUITING

Department of Orthopedics - Skåne University Hospital Malmö

Malmo, Skåne County, 214 28, Sweden

NOT YET RECRUITING

Capio Ortho Center

Malmo, Skåne County, 215 32, Sweden

RECRUITING

Capio Ortho Center Göteborg

Gothenburg, Västra Götaland County, Sweden

RECRUITING

Department of Orthopedics - Eksjö Hospital

Eksjö, 575 81, Sweden

NOT YET RECRUITING

Department of Orthopedics - Falun Hospital

Falun, 791 82, Sweden

NOT YET RECRUITING

Department of Orthopedics - Sahlgrenska University Hospital

Mölndal, 431 80, Sweden

NOT YET RECRUITING

Department of Orthopedics - Östersund Hospital

Östersund, 831 83, Sweden

RECRUITING

Department of Orthopedics - Uppsala University Hospital

Uppsala, 751 85, Sweden

RECRUITING

Department of Orthopedics - Växjö

Vaxjo, 352 34, Sweden

NOT YET RECRUITING

Related Publications (12)

• Ellis SJ, Yu JC, Williams BR, Lee C, Chiu YL, Deland JT. New radiographic parameters assessing forefoot abduction in the adult acquired flatfoot deformity. Foot Ankle Int. 2009 Dec;30(12):1168-76. doi: 10.3113/FAI.2009.1168.

  PMID: 20003875 BACKGROUND

• Iossi M, Johnson JE, McCormick JJ, Klein SE. Short-term radiographic analysis of operative correction of adult acquired flatfoot deformity. Foot Ankle Int. 2013 Jun;34(6):781-91. doi: 10.1177/1071100713475432. Epub 2013 Feb 5.

  PMID: 23386748 BACKGROUND

• Jordan TH, Rush SM, Hamilton GA, Ford LA. Radiographic outcomes of adult acquired flatfoot corrected by medial column arthrodesis with or without a medializing calcaneal osteotomy. J Foot Ankle Surg. 2011 Mar-Apr;50(2):176-81. doi: 10.1053/j.jfas.2010.12.008.

  PMID: 21354002 BACKGROUND

• Mattesi L, Ancelin D, Severyns MP. Is subtalar arthroereisis a good procedure in adult-acquired flatfoot? A systematic review of the literature. Orthop Traumatol Surg Res. 2021 Oct;107(6):103002. doi: 10.1016/j.otsr.2021.103002. Epub 2021 Jun 30.

  PMID: 34216843 BACKGROUND

• Mercun A, Kovacic B, Suhodolcan L, Drobnic M. Patient Outcomes Following Extra-Osseous Talo-Tarsal Stabilization for Foot Hyperpronation. J Foot Ankle Surg. 2022 Mar-Apr;61(2):318-322. doi: 10.1053/j.jfas.2021.09.002. Epub 2021 Sep 9.

  PMID: 34600818 BACKGROUND

• Myerson MS, Badekas A, Schon LC. Treatment of stage II posterior tibial tendon deficiency with flexor digitorum longus tendon transfer and calcaneal osteotomy. Foot Ankle Int. 2004 Jul;25(7):445-50. doi: 10.1177/107110070402500701.

  PMID: 15319100 BACKGROUND

• Osbeck I, Coster M, Montgomery F, Atroshi I. Surgically treated adult acquired flatfoot deformity: Register-based study of patient characteristics, health-related quality of life and type of surgery according to severity. Foot Ankle Surg. 2023 Jun;29(4):367-372. doi: 10.1016/j.fas.2023.03.003. Epub 2023 Mar 15.

  PMID: 36948921 BACKGROUND

• Ozan F, Dogar F, Gencer K, Koyuncu S, Vatansever F, Duygulu F, Altay T. Symptomatic flexible flatfoot in adults: subtalar arthroereisis. Ther Clin Risk Manag. 2015 Oct 16;11:1597-602. doi: 10.2147/TCRM.S90649. eCollection 2015.

  PMID: 26527876 BACKGROUND

• Reilingh ML, Beimers L, Tuijthof GJ, Stufkens SA, Maas M, van Dijk CN. Measuring hindfoot alignment radiographically: the long axial view is more reliable than the hindfoot alignment view. Skeletal Radiol. 2010 Nov;39(11):1103-8. doi: 10.1007/s00256-009-0857-9. Epub 2010 Jan 9.

  PMID: 20062985 BACKGROUND

• Saxena A, Via AG, Maffulli N, Chiu H. Subtalar Arthroereisis Implant Removal in Adults: A Prospective Study of 100 Patients. J Foot Ankle Surg. 2016 May-Jun;55(3):500-3. doi: 10.1053/j.jfas.2015.12.005. Epub 2016 Feb 11.

  PMID: 26874830 BACKGROUND

• Viladot Voegeli A, Fontecilla Cornejo N, Serra Sandoval JA, Alvarez Goenaga F, Viladot Perice R. Results of subtalar arthroereisis for posterior tibial tendon dysfunction stage IIA1. Based on 35 patients. Foot Ankle Surg. 2018 Feb;24(1):28-33. doi: 10.1016/j.fas.2016.10.006. Epub 2016 Nov 5.

  PMID: 29413770 BACKGROUND

• Walley KC, Greene G, Hallam J, Juliano PJ, Aynardi MC. Short- to Mid-Term Outcomes Following the Use of an Arthroereisis Implant as an Adjunct for Correction of Flexible, Acquired Flatfoot Deformity in Adults. Foot Ankle Spec. 2019 Apr;12(2):122-130. doi: 10.1177/1938640018770242. Epub 2018 Apr 12.

  PMID: 29644885 BACKGROUND

MeSH Terms

Conditions

Flatfoot

Condition Hierarchy (Ancestors)

Talipes; Foot Deformities, Acquired; Foot Deformities; Musculoskeletal Diseases; Foot Deformities, Congenital; Lower Extremity Deformities, Congenital; Limb Deformities, Congenital; Musculoskeletal Abnormalities; Congenital Abnormalities; Congenital, Hereditary, and Neonatal Diseases and Abnormalities

Study Officials

• Ida Osbeck, MD

  Region Skane

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Ida Osbeck, MD

CONTACT

+46 708 49 73 79; ida.osbeck@skane.se

Isam Atroshi, MD, PhD

CONTACT

+46 44 309 12 60; isam.atroshi@skane.se

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: November 13, 2023
• First Posted: January 18, 2024
• Study Start: July 31, 2024
• Primary Completion (Estimated): December 31, 2027
• Study Completion (Estimated): December 31, 2029
• Last Updated: December 2, 2025

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will not share

Locations

SE (10)