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How To Perform: Traction Knot and Traction Weight

How To Perform: Traction Knot and Traction Weight

Omar F. Rahman, MD, MBA
Orthopedic Surgery Resident Physician, PGY-5
Lenox Hill Hospital – New York, NY

OK, so you have now successfully placed a proximal tibial or distal femoral skeletal traction pin. The hard part is now done. But what are the next steps? How do you create a traction knot on a rope? How do you apply weight to the skeletal traction pin? And how much weight is enough to add? These skills are rarely taught in textbooks and are learned on-the-job usually from more senior orthopedic residents. In this article, we will break down these questions and demonstrate how to create a perfect traction knot. While there are many different types of knots in terms of stability and security, the traction knot described is reproducible, simple, and effective. This knot does not slip, allows for easy tie and untie, and has the ability to hold an adequate amount of weight. Who knows, mastering this knot may bring out your inner sailor (or at least a strong interest in arthroscopic knot tying). Onboard! 

1. Cut a portion of traction rope approximately 4 feet in length. 

    1. The length is patient-specific and must be long enough to span the patient’s lower leg in the setting of a distal femur or proximal tibia skeletal traction pin. The length should also be long enough to span the edge of the bed and across the traction pulley apparatus. The length can always be shortened so err on the longer side and cut the excess as needed. 

2. Cross the free end over the rope to create a large oval at the end.

3. Cross the free end up and over the rope.  

4. Bring the free end down and over through the large oval. 

    1. Make sure these movements are large and exaggerated. The knot can be further tensioned later.

5. A top oval is created from this passage. Pass the free end up and through the top oval.  

6. Grab the free end and hold tension on this end along with a finger in the bottom oval hole as a counteracting force.  

7. Tension the rope by holding the free end and applying downward pressure in the bottom oval hole. The knot will now tension. 
8. A large traction knot has been created. This can be enlarged or tightened by holding at the level of the knot and pulling the oval end (to enlarge) or the non-free end (to tighten).

9. Place this knot over the traction bow and tighten the knot to secure it. 
10. Funnel the opposite side of the rope through the traction pulley apparatus and assess length to the floor. 
11. Ensure that rope length is adequate.

    1. Rope length should be long enough to clear the bed. 
    2. Rope length should not be at the level of the floor as weights will need to be added.

12. Repeat the above steps to create a traction knot on the hanging weight side.

13. Apply hooked weights to the second traction knot.

When applying weight to the affected limb, it is important to add weight gradually. Usually, approximately 10 to 20 pounds of weight are added to gain length on the fractured limb and to counteract the deforming soft tissue forces. It is common practice to use approximately 10% of the patient’s body weight as weighted traction.

As a general rule of thumb in medicine: start low and go slow. Weight should also be added in small increments. Most hospitals have weights of 2.5, 5, and 10 pounds. Add weight incrementally and assess if the patient is able to tolerate the pull from skeletal traction. Traction should be applied in a direct line of pull to the injured limb. Ensure that the weight is being pulled directly longitudinal from the injured lower extremity. It is also important to note how much torsional bend is occurring at the traction pin site with the addition of weight.

Some institutions elect for a smaller diameter Kirschner wire (K-wire) as a traction pin for both the tibia and femur. Other institutions may elect for a larger diameter Steinmann pin in the distal femur. Be cognizant of the diameter of the traction pin prior to applying weighted traction. Avoid placing more than 20 pounds of weight through the traction pin to decrease the risk of iatrogenic injury.

It is also important to assess the quality of bone in which skeletal traction is being applied. In the younger, healthy patient, the principles above apply. However, astute clinical judgment for skeletal traction is essential in elderly trauma patients. In the setting of an elderly trauma patient with osteopenic bone, use less weight to avoid further injury at the traction pin site.

Lastly, obtain a post-traction x-ray to determine if more or less weight is needed to obtain fracture length. By following these steps in skeletal traction, the orthopedic resident can experience smooth sailing in rough waters.