The Rush pin technique is a specialized method of internal fracture fixation that utilizes flexible, elastic intramedullary pins to stabilize certain types of bone fractures, particularly those involving long bones like the femur. It is designed to provide stable yet flexible support, allowing for controlled motion at the fracture site which can aid in healing.
What is the Rush Pin Technique?
The Rush pin technique is a surgical procedure for treating bone fractures, primarily in long bones. It involves the precise insertion of one or more sterile, curved, and flexible metal pins into the medullary canal (bone marrow cavity) of the fractured bone. These pins exert an elastic, three-point fixation, providing stability while still allowing for some micromotion, which can promote bone healing.
Core Principles of the Rush Pin Technique
The fundamental principle behind the Rush pin technique lies in its unique approach to intramedullary fixation:
- Intramedullary Insertion: Sterile bone pins are carefully inserted into the medulla, which is the bone marrow cavity. This internal placement provides excellent biomechanical stability along the bone's main axis.
- Specific Application: While applicable to various long bone fractures, it is notably used for specific conditions, such as fractures in the os. femur, particularly for parts of the proximal fracture.
- Elastic Fixation: Unlike rigid plates or nails, Rush pins are designed to be flexible. When inserted, their inherent curve creates an elastic force against the inner walls of the bone, providing stability through a three-point contact system. This elastic property allows for controlled dynamic compression at the fracture site.
- Reference Pin Use: A key aspect involves the use of two bone pins. One pin is inserted, and a second pin is then utilized as a reference. This allows the surgeon to accurately check the insertion length of the first pin and estimate the precise position of both the proximal and distal ends of the bone, ensuring optimal placement and fixation.
Applications and Advantages
The Rush pin technique is often considered for oblique or spiral fractures, as well as certain transverse fractures in long bones where a degree of flexibility is desirable for healing.
Key Applications:
- Femur Fractures: Particularly effective for certain types of femoral shaft fractures and some proximal femur fractures.
- Tibia Fractures: Used in specific configurations of tibial shaft fractures.
- Humerus Fractures: Applicable for humeral shaft fractures.
- Pediatric Fractures: Often favored in pediatric orthopedics due to its less invasive nature compared to rigid fixation, preserving growth plates.
Advantages of the Rush Pin Technique:
- Minimally Invasive: Often requires smaller incisions compared to open reduction and internal fixation with plates.
- Biological Fixation: The flexible nature of the pins allows for micro-motion at the fracture site, which can stimulate callus formation and promote natural bone healing.
- Load Sharing: The pins share the load with the bone, rather than bearing all the load, which can reduce stress shielding and promote earlier weight-bearing in some cases.
- Early Mobilization: Depending on the fracture type and stability, patients may be able to begin early range of motion exercises or partial weight-bearing.
- Reduced Risk of Infection: Internal placement within the medulla reduces exposure to the external environment, potentially lowering the risk of superficial infections.
Characteristics of Rush Pins
- Material: Typically made from stainless steel or titanium, chosen for their biocompatibility and elastic properties.
- Shape: Characteristically curved, with a beveled or chisel tip to facilitate insertion and reduce bone damage.
- Sizing: Available in various lengths and diameters to accommodate different bone sizes and fracture types.
The Rush pin technique, with its unique biomechanical properties and meticulous insertion method, remains a valuable tool in the orthopedic surgeon's arsenal for treating specific long bone fractures, balancing stability with biological healing potential.
