## Protocol Section
### Identification Module
**NCT ID:** NCT05643079

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

**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)

#### Organization Study ID Info
**ID:** FDLTransferSharkScrew
#### Organization
**Class:** OTHER
**Full Name:** Orthopedic Hospital Vienna Speising
### Status Module
#### Completion Date
**Date:** 2028-02

**Type:** ESTIMATED

#### Expanded Access Info
#### Last Update Post Date
**Date:** 2023-03-27

**Type:** ACTUAL

**Last Update Submit Date:** 2023-03-23

**Overall Status:** RECRUITING

#### Primary Completion Date
**Date:** 2027-02

**Type:** ESTIMATED

#### Start Date
**Date:** 2022-02-10

**Type:** ACTUAL

**Status Verified Date:** 2023-03

#### Study First Post Date
**Date:** 2022-12-08
**Type:** ACTUAL
**Study First Submit Date:** 2022-10-21
**Study First Submit QC Date:** 2022-12-01
### Sponsor Collaborators Module

#### Lead Sponsor

**Class:** OTHER

**Name:** Orthopedic Hospital Vienna Speising

#### Responsible Party

**Investigator Affiliation:** Orthopedic Hospital Vienna Speising

**Investigator Full Name:** Forian Wenzel-Schwarz

**Investigator Title:** Senior Physician Dr. med.

**Type:** PRINCIPAL_INVESTIGATOR

### Oversight Module

**Is FDA Regulated Device:** False

**Is FDA Regulated Drug:** False

### Description Module

**Brief 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. 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:

* 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.

**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.

### Conditions Module

**Conditions:**

- Flat Feet

- Flexor Tendon Rupture

- Tibialis Posterior Dysfunction

- Deformity, Foot

**Keywords:**

- human allogeneic cortical bone screw

- Shark Screw®

- flat foot deformity

- FDL Transfer

- Tibialis posterior dysfunction

- metal screw

- Bio-Tenodesis screw

- flat foot

### Design Module

#### Design Info

**Observational Model:** CASE_CONTROL

**Time Perspective:** PROSPECTIVE

#### Enrollment Info

**Count:** 40

**Type:** ESTIMATED

**Study Type:** OBSERVATIONAL

### Arms Interventions Module

#### Arm Group 1

**Description:** medializing 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

**Intervention Names:**

- Procedure: medializing calcaneal osteotomy and/or transfer of the flexor digitorum longus tendon (FDL) with metal/Bio-Tenodesis screws

**Label:** metal/Bio-Tenodesis group

#### Arm Group 2

**Description:** 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

**Intervention Names:**

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

**Label:** human, allogeneic cortical bone screw (Shark Screw®)

### Interventions

#### Intervention 1

**Arm Group Labels:**

- metal/Bio-Tenodesis group

**Description:** 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.

**Name:** medializing calcaneal osteotomy and/or transfer of the flexor digitorum longus tendon (FDL) with metal/Bio-Tenodesis screws

**Other Names:**

- Metal/Bio-Tenodesis screw intervention

**Type:** PROCEDURE

#### Intervention 2

**Arm Group Labels:**

- human, allogeneic cortical bone screw (Shark Screw®)

**Description:** 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.

**Name:** medializing calcaneal osteotomy and/or transfer of the flexor digitorum longus tendon (FDL) with Shark Screws®

**Other Names:**

- Shark Screw® intervention

**Type:** PROCEDURE

### Outcomes Module

#### Primary Outcomes

**Description:** bony union will be evaluated

**Measure:** x-ray qualitative evaluation of changes in bony union of calcaneus osteotomy

**Time Frame:** 6 weeks, 6 months, 1 year, 2 years

**Description:** bony union will be evaluated

**Measure:** CT-scan qualitative evaluation of changes in bony union of calcaneus osteotomy

**Time Frame:** 6 months, 1 year

#### Secondary Outcomes

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

**Measure:** changes in AOFAS score in comparison to presurgery

**Time Frame:** 6 months, 1 year and 2 years

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

**Measure:** changes in Foot and Ankle Outcome Score (FOAS) score in comparison to presurgery

**Time Frame:** 6 months, 1 year and 2 years

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

**Measure:** changes in FFI score in comparison to presurgery

**Time Frame:** 6 months, 1 year and 2 years

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

**Measure:** changes in Vas-Pain score in comparison to presurgery

**Time Frame:** 6 weeks, 6 months, 1 year and 2 years

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

**Measure:** complications

**Time Frame:** during surgery, 6 weeks, 6 months, 1 year and 2 years

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

**Measure:** reoperations

**Time Frame:** during surgery, 6 weeks, 6 months, 1 year and 2 years

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

**Measure:** pseudoarthrosis

**Time Frame:** during surgery, 6 months, 1 year and 2 years

### Eligibility Module

**Eligibility Criteria:** Inclusion Criteria

* 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

Exclusion Criteria:

* 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
* 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

**Minimum Age:** 18 Years

**Sampling Method:** NON_PROBABILITY_SAMPLE

**Sex:** ALL

**Standard Ages:**

- 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

### Contacts Locations Module

#### Central Contacts

**Contact 1:**

**Email:** florian.wenzel-schwarz@oss.at

**Name:** Florian Wenzel-Schwarz, MD

**Phone:** +43180182

**Phone Ext:** 3081

**Role:** CONTACT

#### Locations

**Location 1:**

**City:** Vienna

**Contacts:**

***Contact 1:***

- **Email:** florian.wenzel-schwarz@oss.at

- **Name:** Florian Wenzel-Schwarz, MD

- **Phone:** +43180182

- **Phone Ext:** 3081

- **Role:** CONTACT

***Contact 2:***

- **Name:** Florian Wenzel-Schwarz, MD

- **Role:** PRINCIPAL_INVESTIGATOR

**Country:** Austria

**Facility:** Abteilung für Kinderorthopädie und Fußchirurgie Orthopädisches Spital Speising

**Status:** RECRUITING

**Zip:** 1130

#### Overall Officials

**Official 1:**

**Affiliation:** Abteilung für Kinderorthopädie und Fußchirurgie Orthopädisches Spital Speising, Vienna, Austria

**Name:** Florian Wenzel-Schwarz, MD

**Role:** PRINCIPAL_INVESTIGATOR

### IPD Sharing Statement Module

**Description:** due to the sensibility of the row data individual data will only be available on request

**IPD Sharing:** NO

### References Module

#### References

**Citation:** 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.

**PMID:** 35888116

**Citation:** 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.

**PMID:** 33834287

**Citation:** 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.

**PMID:** 34073841

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

**PMID:** 2912622

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

**PMID:** 9880999

**Citation:** 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.

**PMID:** 35924004

**Citation:** 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.

**PMID:** 35373594

**Citation:** 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.

**PMID:** 36765020

**Citation:** 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.

**PMID:** 36757467

## Derived Section

### Condition Browse Module - Ancestors

- ID: D000014947

- Term: Wounds and Injuries

- ID: D000070558

- Term: Talipes

- ID: D000005531

- Term: Foot Deformities, Acquired

- ID: D000009140

- Term: Musculoskeletal Diseases

- ID: D000005532

- Term: Foot Deformities, Congenital

- ID: D000038061

- Term: Lower Extremity Deformities, Congenital

- ID: D000017880

- Term: Limb Deformities, Congenital

- ID: D000009139

- Term: Musculoskeletal Abnormalities

- ID: D000005534

- Term: Foot Diseases

### Condition Browse Module - Browse Branches

- Abbrev: BC16

- Name: Diseases and Abnormalities at or Before Birth

- Abbrev: All

- Name: All Conditions

- Abbrev: BC26

- Name: Wounds and Injuries

- Abbrev: BC05

- Name: Musculoskeletal Diseases

- Abbrev: BC17

- Name: Skin and Connective Tissue Diseases

### Condition Browse Module - Browse Leaves

- ID: M12

- Name: Congenital Abnormalities

- Relevance: HIGH

- As Found: Deformity

- ID: M15241

- Name: Rupture

- Relevance: HIGH

- As Found: Rupture

- ID: M8543

- Name: Flatfoot

- Relevance: HIGH

- As Found: Flat Foot

- ID: M8654

- Name: Foot Deformities

- Relevance: HIGH

- As Found: Deformity, Foot

- ID: M24664

- Name: Posterior Tibial Tendon Dysfunction

- Relevance: HIGH

- As Found: Tibialis Posterior Dysfunction

- ID: M8656

- Name: Foot Deformities, Congenital

- Relevance: LOW

- As Found: Unknown

- ID: M17685

- Name: Wounds and Injuries

- Relevance: LOW

- As Found: Unknown

- ID: M6255

- Name: Clubfoot

- Relevance: LOW

- As Found: Unknown

- ID: M586

- Name: Talipes

- Relevance: LOW

- As Found: Unknown

- ID: M8017

- Name: Equinus Deformity

- Relevance: LOW

- As Found: Unknown

- ID: M8655

- Name: Foot Deformities, Acquired

- Relevance: LOW

- As Found: Unknown

- ID: M12097

- Name: Musculoskeletal Diseases

- Relevance: LOW

- As Found: Unknown

- ID: M24718

- Name: Lower Extremity Deformities, Congenital

- Relevance: LOW

- As Found: Unknown

- ID: M20062

- Name: Limb Deformities, Congenital

- Relevance: LOW

- As Found: Unknown

- ID: M12096

- Name: Musculoskeletal Abnormalities

- Relevance: LOW

- As Found: Unknown

- ID: M8658

- Name: Foot Diseases

- Relevance: LOW

- As Found: Unknown

### Condition Browse Module - Meshes

- ID: D000005413

- Term: Flatfoot

- ID: D000005530

- Term: Foot Deformities

- ID: D000037081

- Term: Posterior Tibial Tendon Dysfunction

- ID: D000000013

- Term: Congenital Abnormalities

- ID: D000012421

- Term: Rupture

### Misc Info Module

- Version Holder: 2024-05-24
