Medical Apparatus: Imaging Guide to Orthopedic Devices

Orthopedic Devices

Joint Arthroplasty

Conservative Fracture Treatment

Internal Fixation - pins, wires, and screws

Internal Fixation - plates

Internal Fixation - rods and nails

Internal Fixation - bone grafts and bone substitutes

Carbon Fiber Implants

Fracture Fixation References

Joint Arthroplasty References




Fracture Fixation

by Tim B Hunter, MD, MSc



Bone fractures can be complete or incomplete, simple or comminuted, closed or open. Comminuted fractures comprise more than two bone fragments, and open fractures are associated with an open skin wound (Ruedi, 2007). Many fractures are treated non-operatively. However, a large number of fractures require operative treatment. If a fracture that requires operative treatment is not treated, nature tries to stabilize the mobile fragments by pain-induced contraction of the surrounding muscles, which may lead to bone shortening. The end result of this process frequently is the lack of proper bone alignment and impaired function, malunion or nonunion (Ruedi, 2007; Benjamin, 1994; Wiss, 2013; Berquist, 1995; Freiberg, 2001; Hunter, 2001).

Stability (stiffness) represents the displacement between fixed fracture fragments when a physiologic load is applied. A stable fracture does not displace under a physiological load. Stability is a principal determinant of whether a fracture is treated conservatively or operatively (Bartolotta, 2019).

The basic goals of fracture fixation are to stabilize the fractured bone, enable fast healing of the injured bone, and return early mobility and full function to the injured extremity. For lower extremity fractures, stability for weight bearing is the main goal. In the upper extremity, restoration of functional hand and arm motion is most important. For diaphyseal fractures, proper alignment of the fracture fragments is all that is needed for adequate function and prompt healing of the fracture, whereas intra-articular fractures require precise anatomic reduction with articular congruency being paramount.

Direct or primary bone (fracture) healing occurs when absolute stability is maintained after an anatomic reduction is achieved, and the fracture ends are compressed together. Direct bone healing requires there be no gap or motion at the fracture site.  In this mode of bone healing, the standard bone turnover process continues as if no fracture is present. The fracture heals directly with new bone formation. The hallmark of this type of healing is the fracture line disappears without the formation of callus.

Indirect or secondary bone (fracture) healing occurs through a cartilage intermediate. Motion at the fracture site creates a micro-environment which causes healing to proceed through several phases: a) inflammation, b) soft callus formation which is predominated by cartilage that helps reduce the motion/strain at the fracture allowing for bone deposition with c) transition to hard callus formation, and finally d) bony remodeling. 

There are two main types of fracture fixation: internal and external. All internal and external fixation methods that allow appreciable interfragmentary movement under functional weight bearing are considered flexible fixation. Techniques that use compression are considered rigid fixation (Ruedi, 2007; Benjamin, 1994; Wiss, 2013).



Conservative Fracture Treatment



Author contact information

Tim Hunter

All Rights Reserved

Publisher Contact Information

Main office: USA (New York)
Cambridge University Press
32 Avenue of the Americas
New York, NY 10013-2473

Phone: (212) 337-5000