Related Experiment Video
Updated: Jan 20, 2026
06:41
A Minimally Invasive Model to Analyze Endochondral Fracture Healing in Mice Under Standardized Biomechanical Conditions
Published on: March 22, 2018
8.6K
Approach to the Perpendicular Fixation of a Scaphoid Waist Fracture-A Computer Analyzed Cadaver Model
Shai Luria1, Samih Badir1, Yonatan Schwarcz1
1Department of Orthopedic Surgery, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
The Journal of Hand Surgery
|August 28, 2019
Summary
Perpendicular screw fixation of scaphoid waist fractures is feasible. Specific approaches in different wrist positions allow for optimal screw placement, potentially improving biomechanical outcomes for horizontal oblique and transverse fractures.
Area of Science:
- Orthopedic surgery
- Biomechanics
- Radiology
Background:
- Scaphoid fracture fixation often uses screws placed along the bone's long axis.
- This standard placement is not perpendicular to common fracture planes (oblique or transverse).
Purpose of the Study:
- To assess the feasibility of placing screws perpendicular to the fracture plane in scaphoid waist fractures.
- To identify optimal surgical approaches for perpendicular screw fixation.
Main Methods:
- Computed tomography (CT) scans of 12 cadaver wrists were analyzed.
- 3D models simulated horizontal oblique (60°) and transverse (90°) scaphoid waist fractures.
- Screw placement feasibility and deviation from perpendicularity were evaluated in wrist flexion, neutral, and extension.
Main Results:
- Proximal-dorsal (flexion) or transtrapezial (neutral/extension) approaches enabled perpendicular screw placement in horizontal oblique fractures.
- Proximal-dorsal/transtrapezial (flexion/neutral) or distal (extension) approaches worked for transverse fractures.
- Perpendicular placement (<10° deviation) in the fracture center was achievable in all specimens.
Conclusions:
- Perpendicular screw fixation is feasible for scaphoid waist fractures (horizontal oblique and transverse).
- Specific approaches (proximal-dorsal, transtrapezial, distal) are viable depending on fracture type and wrist position.
- This technique offers potential biomechanical advantages for scaphoid fracture healing.
Related Concept Videos
01:16Perpendicular-Axis Theorem
4.5K
The perpendicular-axis theorem states that the moment of inertia of a planar object about an axis perpendicular to its plane is equal to the sum of the moments of inertia about two mutually perpendicular concurrent axes lying in the plane of the body.
Consider a circular disc of mass M and radius R lying along an x-y plane. The origin lies at the center of the disc, and the z-axis is perpendicular to the disc's plane. All three axes coincide at the disc's center. The moment of inertia of this...
Consider a circular disc of mass M and radius R lying along an x-y plane. The origin lies at the center of the disc, and the z-axis is perpendicular to the disc's plane. All three axes coincide at the disc's center. The moment of inertia of this...
4.5K
01:03Fixation and Sectioning
7.5K
Two basic types of preparation are used to visualize specimens with a light microscope: wet mounts and fixed specimens.
The simplest type of preparation is the wet mount, in which the specimen is placed in a drop of liquid on the slide. A liquid specimen can be directly deposited on the slide using a dropper. Solid specimens, such as skin scraping, can be placed on the slide before adding a drop of liquid to prepare the wet mount. Sometimes the liquid is simply water, but stains are often added...
The simplest type of preparation is the wet mount, in which the specimen is placed in a drop of liquid on the slide. A liquid specimen can be directly deposited on the slide using a dropper. Solid specimens, such as skin scraping, can be placed on the slide before adding a drop of liquid to prepare the wet mount. Sometimes the liquid is simply water, but stains are often added...
7.5K
01:28Carbon-dioxide Fixation
656
Carbon dioxide fixation in prokaryotes enables the assimilation of inorganic carbon into organic molecules, supporting biosynthetic pathways, sustaining ecosystems, and contributing to the global carbon cycle. It also has industrial applications in carbon capture and bioproduct synthesis. Autotrophic organisms rely on this process to utilize CO₂ as a carbon source in diverse environments.The Calvin CycleThe Calvin cycle is the most widespread carbon fixation mechanism, primarily used by...
656
01:27Fractures: Bone Repair
5.1K
Treatment for a fracture is based on the type of break, the bone affected, and the patient's age.
Minor fractures with no bone displacement are treated by immobilizing the fractured bone using a cast or splint. However, in the case of fractures with displaced bones, the broken bones are repositioned before immobilization to ensure successful healing without deformation and loss of function. The realignment of fractured bone ends is performed through a process called reduction. If the...
Minor fractures with no bone displacement are treated by immobilizing the fractured bone using a cast or splint. However, in the case of fractures with displaced bones, the broken bones are repositioned before immobilization to ensure successful healing without deformation and loss of function. The realignment of fractured bone ends is performed through a process called reduction. If the...
5.1K
01:15Model Approaches for Pharmacokinetic Data: Physiological Models
250
Physiological models in pharmacokinetics are instrumental in understanding the distribution and elimination of drugs within the body. These models describe the drug concentration within target organs, influenced by factors such as drug uptake, tissue volume, and blood flow. Drug uptake is governed by the partition coefficient, which signifies the drug concentration ratio in tissue to that in the blood. The blood flow rate to a specific tissue is expressed as Qt, and the rate of change in tissue...
250
01:14Model Approaches for Pharmacokinetic Data: Compartment Models
534
Compartmental analysis is a widely adopted approach to characterizing drug pharmacokinetics. It uses compartment models that conceptualize the body as a collection of reversibly communicating compartments, each representing a group of tissues exhibiting similar drug distribution characteristics. The movement rate of the drug between these compartments is typically described by first-order kinetics.
Two primary types of compartment models are recognized: mammillary and catenary. The more...
Two primary types of compartment models are recognized: mammillary and catenary. The more...
534