Biodegradable Magnesium Screws for Unstable Ankle Fracture Surgery

Magnesium-Based Screws for Syndesmotic Fixation in Unstable Ankle Fractures

Ankle fractures are among the most common injuries that need surgery. When the broken bones make the ankle unstable, surgeons usually fix them with metal screws and plates. Metal hardware holds the bones in place well, but it can cause irritation, can loosen or break, and often has to be removed in a second surgery later.

This study looks at a different kind of screw called the RemeOs magnesium-based screw. It is made from a magnesium alloy and is designed to slowly dissolve and be absorbed by the body over about two to three years after it has done its job of holding the bone together. Because it dissolves on its own, patients may not need a second surgery to remove the hardware. These screws are authorized by the U.S. Food and Drug Administration (FDA) for use in foot and ankle fracture surgery.

The purpose of this study is to learn how well these magnesium screws work and how safe they are when used to repair unstable ankle fractures. The study will enroll at least 25 adults (ages 18 to 80) who have an unstable ankle fracture that needs surgery. All participants will have their fracture repaired with RemeOs screws as part of their normal surgical care.

After surgery, participants will be followed for 12 months. They will return for check-ups at about 6 weeks, 3 months, 6 months, and 12 months. At these visits, the study team will examine the ankle, take X-rays to see how the bone is healing and how the screws are dissolving, ask about any complications, and have participants fill out questionnaires about their ankle function and pain.

The main thing the study measures is ankle function at 12 months, scored using a standard ankle questionnaire (the Olerud-Molander Ankle Score). The study also tracks pain, healing on X-rays, how the screws break down over time, and any complications such as infection, loss of fixation, non-healing, or the need for additional surgery.

The surgery, X-rays, and follow-up visits in this study are the same care patients would receive whether or not they take part. The only research-specific parts are giving consent and filling out the study questionnaires. Taking part is voluntary and does not change the care a patient receives.

Study Overview

• Status: Not yet recruiting
• Conditions: Ankle Fractures; Syndesmotic Injury
• Intervention / Treatment: Device: RemeOs Magnesium-Based Biodegradable Screw

Detailed Description

Background: A substantial proportion of operatively treated lower-extremity injuries are ankle fractures, including unimalleolar, bimalleolar, bimalleolar-equivalent, and trimalleolar patterns, often with associated distal tibiofibular syndesmotic instability. Conventional metallic fixation provides reliable initial stability but carries well-recognized drawbacks, including hardware irritation, implant breakage or loosening, and the frequent need for secondary removal procedures-particularly for syndesmotic screws. Magnesium-based biodegradable implants are designed to provide sufficient mechanical stability during fracture healing while gradually degrading, thereby eliminating routine hardware removal. RemeOs magnesium-based screws (Bioretec), composed of a magnesium-calcium-zinc alloy, are FDA-authorized for fracture fixation in foot and ankle surgery and are absorbed over approximately 2 to 3 years.

Design: This is a prospective, single-arm, interventional, post-market clinical follow-up study. A minimum of 25 patients (planned enrollment of 28 to allow for attrition) will be enrolled at participating Mass General Brigham sites. Fellowship-trained orthopaedic foot and ankle surgeons will perform all procedures.

Intervention: All participants will undergo open reduction and internal fixation (ORIF) of their ankle fracture using RemeOs magnesium-based biodegradable screws for fracture fixation and/or syndesmotic stabilization, in accordance with the device Instructions for Use. RemeOs screw types (Screw LAG, Screw COM, Screw FT, and Screw LAG Solid) may be used at the surgeon's discretion. Fixation of additional fracture components may be supplemented with plates, K-wires, or non-resorbable screws as clinically indicated.

Assessments: Participants are evaluated preoperatively (baseline characteristics, radiographs, and patient-reported outcomes) and postoperatively at 6 weeks, 3 months, 6 months, and 12 months, with an optional 9-month visit if delayed healing or complications are suspected. Each follow-up includes clinical examination, radiographic assessment of healing and screw biodegradation, complication assessment, and patient-reported outcomes.

Primary outcome: Functional recovery measured by the Olerud-Molander Ankle Score (OMAS) at 12 months.

Secondary outcomes: OMAS at 3 and 6 months; radiographic fracture healing and alignment; radiographic evaluation of RemeOs screw biodegradation; complication rates (loss of fixation, infection, non-union, revision surgery); pain intensity (Visual Analog Scale); and PROMIS Physical Function and Pain Interference.

Statistical analysis: Longitudinal OMAS changes will be analyzed using a linear mixed-effects model with time as a fixed effect and subject as a random effect. Secondary outcomes will be summarized descriptively; continuous variables compared with paired t-tests or Mann-Whitney U tests as appropriate; time to revision evaluated by Kaplan-Meier analysis where applicable. A p-value < 0.05 is considered significant.

All clinical procedures (surgery, imaging, follow-up) are standard care delivered regardless of study participation; the only research-specific procedures are informed consent and completion of patient-reported outcome measures.

• Study Type: Interventional
• Enrollment (Estimated): 28
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Mani Eftekhari, BS; Phone Number: 15108506056; Email: meftekhari@mgh.harvard.edu

Study Locations

• United States
  • Massachusetts
    • Boston, Massachusetts, United States, 02114
      • Massachusetts General Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age 18-80 years
• Unstable closed ankle fracture requiring surgical fixation, including unimalleolar, bimalleolar, bimalleolar-equivalent, or trimalleolar fractures
• Fractures may be with or without syndesmotic instability
• Willingness to follow postoperative visits and rehabilitation protocols
• Ability to complete patient-reported outcome measures (PROMs)

Exclusion Criteria:

• Body mass index (BMI) > 40
• Open fractures
• Pathologic fractures
• Active infection at the surgical site
• Known allergy or hypersensitivity to magnesium or implant components
• Severe peripheral vascular disease
• Uncontrolled diabetes mellitus
• Prior ankle surgery on the affected limb
• Concomitant osteochondral lesions requiring treatment
• Neuromuscular disorders affecting the lower extremity
• Worker's compensation cases
• Pregnancy
• Non-adherence concerns or inability to comply with follow-up requirements

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: RemeOs Magnesium Screw Fixation; All participants undergo open reduction and internal fixation (ORIF) of their unstable ankle fracture using RemeOs magnesium-based biodegradable screws for fracture fixation and/or syndesmotic stabilization, in accordance with the device Instructions for Use. Screw type is selected at the surgeon's discretion. Additional fracture components may be supplemented with plates, K-wires, or non-resorbable screws as clinically indicated. Participants are followed for 12 months postoperatively.

Device: RemeOs Magnesium-Based Biodegradable Screw; ORIF performed using RemeOs magnesium-alloy biodegradable screws (Screw LAG, Screw COM, Screw FT, and/or Screw LAG Solid) for fixation of any malleolus and/or for syndesmotic fixation where indicated, per the device Instructions for Use. The screws provide mechanical stability during healing and gradually biodegrade over approximately 2-3 years, eliminating the need for routine hardware removal.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Olerud-Molander Ankle Score (OMAS)	Functional recovery assessed by the Olerud-Molander Ankle Score, a patient-reported instrument scored 0 to 100, where 0 indicates totally impaired and 100 indicates no impairment. Higher scores indicate better ankle function.	12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Radiographic Fracture Healing and Alignment	Radiographic assessment of fracture union and maintenance of anatomic alignment of the ankle mortise on serial postoperative radiographs.	6 weeks, 3 months, 6 months, and 12 months postoperatively
Radiographic RemeOs Screw Biodegradation	Radiographic evaluation of the biodegradation behavior of the RemeOs magnesium-based screws over time, including gas formation and implant resorption.	3 months, 6 months, and 12 months postoperatively
Complication Rate	Proportion of participants experiencing complications, including loss of fixation, infection, non-union, and revision surgery.	12 months
Pain Intensity	Pain intensity measured on a Visual Analog Scale ranging from 0 (no pain) to 10 (worst imaginable pain); lower scores indicate less pain.	Baseline, 6 weeks, 3 months, 6 months, and 12 months postoperatively
PROMIS	PROMIS Physical Function and PROMIS Pain Interference.	Baseline, 6 weeks, 3 months, 6 months, and 12 months postoperatively

Collaborators and Investigators

• Sponsor: Massachusetts General Hospital
• Collaborators: Bioretec Ltd.

Study record dates

Study Major Dates

• Study Start (Estimated): August 1, 2026
• Primary Completion (Estimated): February 1, 2029
• Study Completion (Estimated): March 1, 2029

Study Registration Dates

• First Submitted: July 3, 2026
• First Submitted That Met QC Criteria: July 3, 2026
• First Posted (Actual): July 9, 2026

Study Record Updates

• Last Update Posted (Actual): July 9, 2026
• Last Update Submitted That Met QC Criteria: July 3, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Magnesium-based screw; Biodegradable implant
• Additional Relevant MeSH Terms: Wounds and Injuries; Leg Injuries; Fractures, Bone; Ankle Injuries; Ankle Fractures
• Other Study ID Numbers: 2026P000142

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will be stored within Mass General Brigham and accessed only by IRB-approved study staff. Per the study protocol, data will not be shared outside the institution, and no biological specimens are collected.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No