An observational study in Flat Feet, Flexor Tendon Rupture and Tibialis Posterior Dysfunction, sponsored by Orthopedic Hospital Vienna Speising. Recruiting at 1 site in Austria. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-03-20.
Sponsored by Orthopedic Hospital Vienna Speising · Observational
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:
Participants will have
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.
173 studies on the registry are indexed under Flatfoot; 44 are open to participants now.
This study's planned enrollment of 40 is below the median of 47 across 48 observational studies indexed under Flatfoot.
Browse Flatfoot studies →Orthopedic Hospital Vienna Speising is the lead sponsor of 9 studies on the registry; 2 are open to participants now.
Counted across the registry records on this site, refreshed daily.
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
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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
Procedure: medializing calcaneal osteotomy and/or transfer of the flexor digitorum longus tendon (FDL) with metal/Bio-Tenodesis screws
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
Procedure: medializing calcaneal osteotomy and/or transfer of the flexor digitorum longus tendon (FDL) with Shark Screws®
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.
Also known as: 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 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.
Also known as: Shark Screw® intervention
x-ray qualitative evaluation of changes in bony union of calcaneus osteotomy
bony union will be evaluated
Time frame: 6 weeks, 6 months, 1 year, 2 years
CT-scan qualitative evaluation of changes in bony union of calcaneus osteotomy
bony union will be evaluated
Time frame: 6 months, 1 year
changes in AOFAS score in comparison to presurgery
The American Orthopedic Foot and Ankle Score (AOFAS) units in percent (%), the higher the better
Time frame: 6 months, 1 year and 2 years
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
Time frame: 6 months, 1 year and 2 years
changes in FFI score in comparison to presurgery
Foot Function Index units in percent (%), the higher the better
Time frame: 6 months, 1 year and 2 years
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
Time frame: 6 weeks, 6 months, 1 year and 2 years
complications
Complications will be recorded during surgery and the kind of complication described, number of patients with complications are given
Time frame: during surgery, 6 weeks, 6 months, 1 year and 2 years
reoperations
Reoperations will be recorded when needed and the kind of re-operation and number of patients with reoperations are given
Time frame: during surgery, 6 weeks, 6 months, 1 year and 2 years
pseudoarthrosis
Pseudarthrosis will be recorded at the follow up at 2 years and number of patients with Pseudarthrosis are given
Time frame: during surgery, 6 months, 1 year and 2 years
Plan to share: No — due to the sensibility of the row data individual data will only be available on request
Started Feb 2022 (actual). Primary completion is estimated for Feb 2027, 60 months after the start.
Of 16 observational studies under Flatfoot, half reached primary completion within 6 months of starting (the median), counting those still running; a quarter within 2 and three quarters within 25. This study's planned 60 months is above that.
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Orthopedic Hospital Vienna Speising