Analysis of Medial Clear Space Widening in Weber B Ankle Fractures

• Conditions: Weber B Ankle Fractures

• Registration Number: NCT07028944
• Lead Sponsor: University of Utah

Brief Summary

The investigators purpose of this study is to obtain all three standard of care stress views of the ankle (gravity stress, manual stress, weightbearing stress) to compare the amount of tibiotalar joint instability predicted by each to determine if there are significant differences measured by the differing stress techniques.

Detailed Description

Rotational ankle injuries are a commonly encountered injury. Classification of these injuries is most commonly by the Danis-Weber (or Weber) classification and the Lauge-Hansen classification.

Within this classification system exists the isolated Weber B or Lauge-Hansen Supination External Rotation 2/4 (SER 2/4) injury which radiographically involves an isolated spiral fracture of the lateral malleolus at the level of the tibiofibular syndesmosis.

The difference between SER2 (isolated) Weber B injuries and SER4 injuries is disruption of the medial ankle mortise structures, either the medial malleolus (4a) or deltoid ligaments (4b) which then can permit increased talar subluxation with potential to result in tibitotalar joint incongruity.

Standard practice is to proceed with operative fixation of rotationally unstable Weber B or SER4b injuries.

To determine the competence of medial ligamentous structures in isolated fractures of the fibula at the level of the syndesmosis when there is minimal widening of the mortise on non weight bearing films there are three plain x-ray views currently widely used and considered standard of care:

1. manual external rotation stress;

2. gravity assisted stress;

3. and weight-bearing stress radiographs.

Increased widening on one of these views is used to decide whether to treat the fracture with or without surgery.

Globally there is wide variability as to which stress-view radiograph or combination of these are used. To our knowledge, no study to date has compared all three stress-view radiographs concurrently to determine if the three different methods predict equal amounts of tibiotalar joint instability.

The need to understand how these three views compare is crucial, as tibiotalar instability is primary indication for surgical stabilization.

The null hypothesis therefore is the investigators will find no difference in the tibiotalar joint instability between the three stress views.

Study Timeline

• Study Start: 2023-05-25
• Status Verified: 2025-06
• Study First Submitted: 2025-06-03
• Study First Submitted QC: 2025-06-17
• Last Update Submitted: 2025-06-17
• Study First Posted: 2025-06-19
• Last Update Posted: 2025-06-19
• Primary Completion: 2026-05
• Study Completion: 2026-05

Recruitment & Eligibility

• Status: ENROLLING_BY_INVITATION
• Sex: All
• Target Recruitment: 60

Inclusion Criteria

• Patients with a Weber B ankle fracture who are skeletally mature (no open physes) and older than 18 years of age.

Exclusion Criteria

• Medial and/or posterior Malleolar fracture
• Any other lower extremity trauma that limits weight bearing
• Concomitant arthridities/rheumatologic disease (patients with osteoarthritis may be included)
• Prior fracture
• Prior surgery of foot, talus or ankle
• Open fracture
• Initial NWB xrays with a medial clear space (MCS) > 7 mm or medial clear space> superior clear space (SCS) by 2mm, signifying an unstable fracture prior to stress
• Protected populations

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Medial Clear Space (MCS) Widening Under Gravity Assisted Stress	Day 1 Clinic Visit	Measured distance, millimeters(mm) of the fractured fibula at the level of the syndesmosis joint in patients undergoing gravity assisted stress
Medial Clear Space (MCS) Widening Under Manual External Rotation Stress	Day 1 Clinic Visit	Measured distance, millimeters(mm) of the fractured fibula at the level of the syndesmosis joint in patients undergoing manual external rotation stress
Medial Clear Space (MCS) Widening Under Weight-bearing Stress	Day 1 Clinic Visit	Measured distance, millimeters(mm) of the fractured fibula at the level of the syndesmosis joint in patients undergoing weight-bearing stress

Trial Locations

Locations (1)

University of Utah Orthopedics; 🇺🇸 Salt Lake City, Utah, United States