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Flat FeetNCT05643079

Medial Displacement Calcaneal Osteotomy and FDL- Transfer - With a Human, Allogeneic Cortical Bone Screw

An observational study of Flat Feet and Flexor Tendon Rupture, run by Orthopedic Hospital Vienna Speising at 1 site in Austria.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial summary

The goal of this observational study is to compare the use of a screw made of human bone (Shark-Screw®, Surgebright-GmbH) with the metal/Bio-Tenodesis screw (Arthrex) in the treatment of the symptomatic flatfoot using the medializing calcaneus osteotomy with flexor digitorum longus transfer (FDL) in adult patients. Read more about this study

Who is it for?
Ages 18 years and older
What is being tested?
medializing calcaneal osteotomy and/or transfer of the flexor digitorum longus tendon (FDL) with metal/Bio-Tenodesis screws and medializing calcaneal osteotomy and/or transfer of the flexor digitorum longus tendon (FDL) with Shark Screws®
Type of treatment
Surgery or procedure
How many people
40 participants
Where
1 siteAustria
Study dates
10 Feb 2022to Feb 2028
Phase
Observational
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Study population: adult patients with an indication for the use of a metal/Bio-Tenodesis screw or human bone screw in medializing calcaneus osteotomy with/without FDL transfer. The patient has the choice of the treatment method after explanation advantages and disadvantages for each surgery method

Who may be able to join

  • Indication for the use of a metal/Bio-Tenodesis screw or human bone screw in medializing calcaneus osteotomy with FDL transfer.
  • BMI< 40 kg/m²

Who cannot join

  • Insufficient knowledge of German
  • Alcohol and drug abuse
  • Pregnant woman or nursing mother
  • Foreseeable compliance problems
  • Neoplastic diseases, malignant bone tumors, rheumatoid arthritis
  • Active osteomyelitis
Show all 11Show fewer
  • History of foot surgery
  • Advanced osteoarthritis of the lower ankle joint
  • Ulcerations in the skin of the surgical area
  • Immunosuppressive medications that cannot be discontinued
  • BMI >40

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Florian Wenzel-Schwarz, MD contact

+43180182 ext. 3081

florian.wenzel-schwarz@oss.at

Austria1 site, 1 recruiting

  • Abteilung für Kinderorthopädie und Fußchirurgie Orthopädisches Spital Speising

    Vienna, 1130

    Florian Wenzel-Schwarz, MD, +43180182 ext. 3081, florian.wenzel-schwarz@oss.at

    Florian Wenzel-Schwarz, MD

    Recruiting

Other trials in Austria

About this study

Official title: Medial Displacement Calcaneal Osteotomy and FDL- Transfer - a Prospective Comparative Study Between Metal/Bio-Tenodesis Screw (Arthrex) and the Human, Allogeneic Cortical Bone Screw (Shark Screw®️, Surgebright-GmbH)

The goal of this observational study is to compare the use of a screw made of human bone (Shark-Screw®, Surgebright-GmbH) with the metal/Bio-Tenodesis screw (Arthrex) in the treatment of the symptomatic flatfoot using the medializing calcaneus osteotomy with flexor digitorum longus transfer (FDL) in adult patients. The advantage of the human bone screw is that after surgery no hardware removal is necessary. The screw is transformed from the body to normal bone.

The main questions it aims to answer are:

Read more
  • Can the human bone screw achieve union rates like the metal/Bio-Tenodesis screw?
  • Is the time to union similar between the different screws?
  • Is the complication rate similar between the different screws?
  • Are the activity scores American Orthopaedic Foot and Ankle Society (AOFAS), Foot and Ankle Outcome Score (FAOS) and Foot Function Index (FFI) after surgery similar in the compared patient groups?

Participants will have

  • the surgery
  • follow-ups at 6 weeks, 6 months, 1 and 2 years.
  • X-rays are performed at each follow up.
  • CT-scans are performed after 6 months.
  • activity scores are collected at the follow up after 6 months, 1 year and 2 years.
Read the detailed description

Symptomatic flatfoot deformity in adults often occurs as a result of dysfunction of the Tibialis posterior tendon (TPTD), with a prevalence of 3.3%. Structured non-surgical treatment programs with orthotics and physiotherapy can achieve a high level of long-term subjective and functional satisfaction, with surgery being avoided in 70-89% of cases. Surgical intervention is indicated for progressive or uncontrolled symptoms. Flexible flatfoot deformity, stage II classified by Johnson and Strom, can be treated with a joint-preserving strategy, which usually includes a medializing calcaneal osteotomy, debridement of the tibialis posterior tendon, and transfer of the flexor digitorum longus (FDL) tendon. 87% satisfaction after ten years was observed in both pain relief and foot function and alignment.

Metal screws have been used for decades to treat bone fractures. The removal is the major disadvantage of conventional osteosyntheses and requires a second operation, with all the resulting risks of complications for each patient. The use of the bone screw from allogeneic cortical bone would reduce costs substantially, with a significant reduction in the average complication rate to 0.3%.

The idea of stabilizing fractures using compact bone instead of metal is not new. Obwegeser published the clinical use of 796 screw implants of allogeneic bone and reported that the only complication was the fracture of 6 screws (<1%) and three screw loosening (<0,5%).

Since 2016, the human, allogeneic cortical bone screw(Shark Screw®) has been used by two tissue banks, the Austrian Austrian tissue bank Surgebright-GmbH and the German Institute for Cell and Tissue Replacement (DIZG). The Shark Screw® graft was approved by the competent Austrian authority (AGES) in 2016. The bone graft immediately creates a solid, purely bony connection. This leads to bone remodeling, bone incorporation and optimal reparation in the surgical area. Depending on the loads and requirements, the bone connection adapts for the future. The bone grafts undergo a certified sterilization procedure at the DIZG, which was developed in 1985 at the Berlin Charité.

Due to the lack of further systematic investigations to objectively confirm the theoretically given and subjectively experienced product advantages, this observational study is now being conducted.

The aim of the present study is to evaluate the application of the human allogeneic cortical bone screw (Shark Screw®) and the metal/Bio-Tenodesis screw in the surgical treatment (medializing calcaneus osteotomy with FDL transfer) of symptomatic flatfoot and to systematically document corresponding clinical and radiological parameters before and after surgery.

Being tested
medializing calcaneal osteotomy and/or transfer of the flexor digitorum longus tendon (FDL) with metal/Bio-Tenodesis screws, medializing calcaneal osteotomy and/or transfer of the flexor digitorum longus tendon (FDL) with Shark Screws®
Keywords
human allogeneic cortical bone screw, Shark Screw®, flat foot deformity, FDL Transfer, Tibialis posterior dysfunction, metal screw, Bio-Tenodesis screw, flat foot
Medical subject headings
Flatfoot, Posterior Tibial Tendon Dysfunction, Foot Deformities

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • medializing calcaneal osteotomy and/or transfer of the flexor digitorum longus tendon (FDL) with metal/Bio-Tenodesis screwsProcedure or surgery

    Also called Metal/Bio-Tenodesis screw intervention

    The calcaneus osteotomy is performed dorsal proximal to plantar distal with caution of the peroneal tendons and sural nerve. After mobilization the dorsal fragment is displaced medially by~10mm. Thereafter, a guide wire is placed from plantar-lateral into the ventral portion of the calcaneus under fluoroscopic control. After stab incision and length measurement, the osteotomy is fixed with a Metal/Bio-Tenodesis screw(MBS). The lateral projection of the edge is straightened. Opening of the tendon sheath of the FDL muscle and dissection distally to Henry's node. Settling of the tendon and arming with a "shuttle suture". Tendon diameter measurement. Place a guide wire at os naviculare directed from plantar to dorsal in 20°proximal guidance. Pull through the FDL tendon from plantar to dorsal and fixation with an MBS in 20°of pointed foot position and inversion with appropriate desired tension. The tendon is then sutured to the stump of the tibialis posterior tendon, retinaculum sutures.

  • medializing calcaneal osteotomy and/or transfer of the flexor digitorum longus tendon (FDL) with Shark Screws®Procedure or surgery

    Also called Shark Screw® intervention

    The calcaneus osteotomy is performed dorsal proximal to plantar distal with caution of the peroneal tendons and sural nerve. After mobilization the dorsal fragment is displaced medially by approx.10mm. Thereafter, a guide wire is placed from plantar-lateral into the ventral portion of the calcaneus under fluoroscopic control. After stab incision and length measurement, the osteotomy is fixed with a Shark Screw®. The lateral projection of the edge is straightened. Opening of the tendon sheath of the FDL muscle and dissection distally to Henry's node. Settling of the tendon and arming with a "shuttle suture". Tendon diameter measurement. Place a guide wire at os naviculare directed from plantar to dorsal in 20°proximal guidance. Pull through the FDL tendon from plantar to dorsal and fixation with the Shark Screw® in 20°of pointed foot position and inversion with appropriate desired tension. The tendon is then sutured to the stump of the tibialis posterior tendon, retinaculum sutures.

Study groups in NCT05643079
Study groupRoleWhat they receive
metal/Bio-Tenodesis groupmedializing calcaneal osteotomy, debridement of the tibialis posterior tendon, and/or transfer of the flexor digitorum longus (FDL) tendon with the following screws: Metal-/Bio-Tenodesis screw (Arthrex, Naples, Florida, USA) Metal-Screw: ø 6,7 mm length: 40-60 mm Bio-Tenodesis screw: ø 4,00 mm, length: 10 mm ø 4,75 mm, length: 15 mm ø 5,50 mm, length: 15 mm
Receives: Procedure: medializing calcaneal osteotomy and/or transfer of the flexor digitorum longus tendon (FDL) with metal/Bio-Tenodesis screws
human, allogeneic cortical bone screw (Shark Screw®)medializing calcaneal osteotomy, debridement of the tibialis posterior tendon, and/or transfer of the flexor digitorum longus (FDL) tendon with the following screws: Shark Screw® (Surgebright-GmbH, 4040 Lichtenberg, Austria) Versions used: Shark Screw® diver ø: 5,0 mm, length: 35 mm Shark Screw® diver ø: 5,0 mm, length: 45 mm Shark Screw® tendon ø: 5,0 mm, length: 15 mm
Receives: Procedure: medializing calcaneal osteotomy and/or transfer of the flexor digitorum longus tendon (FDL) with Shark Screws®

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. x-ray qualitative evaluation of changes in bony union of calcaneus osteotomy

    bony union will be evaluated

    Measured: 6 weeks, 6 months, 1 year, 2 years

  2. CT-scan qualitative evaluation of changes in bony union of calcaneus osteotomy

    bony union will be evaluated

    Measured: 6 months, 1 year

Secondary outcomes (7)

  1. changes in AOFAS score in comparison to presurgery

    The American Orthopedic Foot and Ankle Score (AOFAS) units in percent (%), the higher the better

    Measured: 6 months, 1 year and 2 years

  2. changes in Foot and Ankle Outcome Score (FOAS) score in comparison to presurgery

    Foot and Ankle Outcome Score units in percent (%), the higher the better

    Measured: 6 months, 1 year and 2 years

  3. changes in FFI score in comparison to presurgery

    Foot Function Index units in percent (%), the higher the better

    Measured: 6 months, 1 year and 2 years

  4. changes in Vas-Pain score in comparison to presurgery

    Visual Analog Scale Pain Score values between 0 and 10, 0= no pain, 10 sever pain

    Measured: 6 weeks, 6 months, 1 year and 2 years

  5. complications

    Complications will be recorded during surgery and the kind of complication described, number of patients with complications are given

    Measured: during surgery, 6 weeks, 6 months, 1 year and 2 years

  6. reoperations

    Reoperations will be recorded when needed and the kind of re-operation and number of patients with reoperations are given

    Measured: during surgery, 6 weeks, 6 months, 1 year and 2 years

  7. pseudoarthrosis

    Pseudarthrosis will be recorded at the follow up at 2 years and number of patients with Pseudarthrosis are given

    Measured: during surgery, 6 months, 1 year and 2 years

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted8 Dec 2022
  2. Study start10 Feb 2022
  3. Primary completionFeb 2027 (estimated)
  4. Study completionFeb 2028 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Observational
Observational model
Case-control
Time perspective
Prospective
Enrolment
40 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05643079
Sponsor's protocol ID
FDLTransferSharkScrew
Status last verified
Mar 2025
First submitted
21 Oct 2022
Last updated
20 Mar 2025
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No: due to the sensibility of the row data individual data will only be available on request

Publications

  • Pastl K, Pastl E, Flory D, Borchert GH, Chraim M. Arthrodesis and Defect Bridging of the Upper Ankle Joint with Allograft Bone Chips and Allograft Cortical Bone Screws (Shark Screw(R)) after Removal of the Salto-Prosthesis in a Multimorbidity Patient: A Case Report. Life (Basel). 2022 Jul 11;12(7):1028. doi: 10.3390/life12071028.

    PubMed 35888116

  • Pastl K, Schimetta W. The application of an allogeneic bone screw for osteosynthesis in hand and foot surgery: a case series. Arch Orthop Trauma Surg. 2022 Oct;142(10):2567-2575. doi: 10.1007/s00402-021-03880-6. Epub 2021 Apr 8.

    PubMed 33834287

  • Brcic I, Pastl K, Plank H, Igrec J, Schanda JE, Pastl E, Werner M. Incorporation of an Allogenic Cortical Bone Graft Following Arthrodesis of the First Metatarsophalangeal Joint in a Patient with Hallux Rigidus. Life (Basel). 2021 May 24;11(6):473. doi: 10.3390/life11060473.

    PubMed 34073841

  • Johnson KA, Strom DE. Tibialis posterior tendon dysfunction. Clin Orthop Relat Res. 1989 Feb;(239):196-206.

    PubMed 2912622

  • Obwegeser JA. [Absorbable and bioconvertible osteosynthesis materials in maxillofacial surgery]. Mund Kiefer Gesichtschir. 1998 Nov;2(6):288-308. doi: 10.1007/s100060050077. German.

    PubMed 9880999

  • Hanslik-Schnabel B, Flory D, Borchert GH, Schanda JE. Clinical and Radiologic Outcome of First Metatarsophalangeal Joint Arthrodesis Using a Human Allogeneic Cortical Bone Screw. Foot Ankle Orthop. 2022 Jul 29;7(3):24730114221112944. doi: 10.1177/24730114221112944. eCollection 2022 Jul.

    PubMed 35924004

  • Amann P, Pastl K, Neunteufel E, Bock P. Clinical and Radiologic Results of a Human Bone Graft Screw in Tarsometatarsal II/+III Arthrodesis. Foot Ankle Int. 2022 Jul;43(7):913-922. doi: 10.1177/10711007221081533. Epub 2022 Apr 2.

    PubMed 35373594

  • Sailer S, Lechner S, Flossmann A, Wanzel M, Habeler K, Krasny C, Borchert GH. Treatment of scaphoid fractures and pseudarthroses with the human allogeneic cortical bone screw. A multicentric retrospective study. J Orthop Traumatol. 2023 Feb 10;24(1):6. doi: 10.1186/s10195-023-00686-7.

    PubMed 36765020

  • Krasny C, Radda C, Polke R, Schallmayer D, Borchert GH, Albrecht C. A human, allogeneic cortical bone screw for distal interphalangeal joint (DIP) arthrodesis: a retrospective cohort study with at least 10 months follow-up. Arch Orthop Trauma Surg. 2023 Jul;143(7):4557-4564. doi: 10.1007/s00402-023-04785-2. Epub 2023 Feb 9.

    PubMed 36757467

Questions about this trial

What is this clinical trial studying?

An observational study of Flat Feet and Flexor Tendon Rupture, run by Orthopedic Hospital Vienna Speising at 1 site in Austria.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 2 inclusion and 11 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: looking for participants now, as of the sponsor's last update on 20 Mar 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Austria. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Florian Wenzel-Schwarz, MD (+43180182 ext. 3081, florian.wenzel-schwarz@oss.at), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

x-ray qualitative evaluation of changes in bony union of calcaneus osteotomy (time frame: 6 weeks, 6 months, 1 year, 2 years). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05643079, which also lists 9 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Mar 2025.

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