Skeletal traction is a type of traction where the force is applied directly to the bone by inserting metal pins/screws in the bone.
This is in contrast to the skin traction which applies the force on the limb through the skin surface.
Traction is one of the oldest orthopedic treatment methods used for fracture, pain control, and deformity correction.
With advances in surgical methods, the use of traction is not that common but is still an indispensable part of orthopedic treatment.
The main goals of traction are
- Pain control
- Fracture fragment alignment
- Prevention and correction of the deformity
Traction and Countertraction Concept
Traction is often applied to part of the body to negate the effect of the forces causing the deformity. To be effective, the traction should act on the deformity and not the whole body. To counter the effect on the whole body we need another force that acts in opposite direction.
This is countertraction.
If we pull a person’s hand ad there is no resistance it would result in pulling a person toward you. However if a person holds him from the elbow, all your force is transferred to the forearm only. This is another example of traction and countertraction forces,
In orthopedic practice,countertraction may be obtained by altering the angle of the body-weight force in relation to the pull of traction, such as by elevating the foot of the bed with blocks to enable body weight to act as a counterforce.
Countertraction is an important aspect of traction treatment.
The absence of counteraction not only results in ineffective traction but also in the discomfort of the patient.
Pins and Screws for Skeletal Traction
Skeletal traction requires pins or wires to be driven into the bone which allows putting traction directly on the skeleton. Therefore, it is an invasive procedure. It requires greater skill and expertise than applying the skin traction.
Skeletal traction is used in cases where a heavier pull is required or when skin traction is not appropriate for the body part needing treatment.
Following pins and screws are commonly used in skeleton traction
- Steinman pin
- Denham pin [similar Steinman pin but threaded in the middle
Inserting a pin or screw is a surgical procedure and requires all sterile precautions. It also requires extensive care after the procedure for the prevention of complications like infection.
Screws are used in metacarpal and olecranon traction mainly.
It is important to place the pins correctly. The pins must be clean to avoid infection. Damage may result if the alignment and weights are not carefully calibrated.
Skeletal traction is most commonly employed in lower limbs and is rarely employed for upper limb problems.
Steinman pin is commonly used for insertion in the bone and the upper tibial site is the most common site.
Different Types of Skeletal Traction
Skeletal traction can be a fixed type or sliding type. Fixed skeletal traction is traction between two points whereas sliding traction uses the patient’s weight as countertraction.
Various types of skeletal tractions have been devised depending on the issue they address. Most of them are known by the names of their inventors.
Important ones are described below.
Skull calipers are applied in cervical injury and also after surgeries on the cervical spine. Many types of calipers are available which differ in their design and application but achieve the same purpose.
Gardener-Wells tongs and Crutchfield tongs are most commonly used.
The calipers are designed to insert in the outer cortex of the skull and this is done after sterile preparation about 1 cm above and in line with the pinna bilaterally. The cord is tied on the other end of the tong and passed over the pulley and weights are attached.
The weight applied will vary with the injury level.
It is a type of fixed traction used in cervical injuries and immobilization. It is a device that consists of a ring that encircles the head and is attached to it via pins to the outer portion of the skull. The ring is connected to a vest-like splint. the combination allows the mobility of the patient along with providing traction.
This traction is used for acetabular fractures, hip fractures, and proximal femur fractures especially when there is a ligament injury to the knee.
Steinmann pin for traction is inserted at the lower end of the femur slightly proximal to the adductor tubercle. The direction of insertion of the Steinman pin is from the medial to the lateral side.
The traction bow is used to transmit the weight to produce traction with an upward force. The leg is supported with U-Loops to keep it horizontally lifted. This creates a position of 90 degrees flexion at the hip and knee both, hence the name.
There could be various modifications depending on the requirement of the traction.
Proximal Tibial Traction
Proximal tibial traction is indicated for
- Hip fractures
- Acetabular fractures
- Femoral shaft fractures
- Subtrochanteric fractures
Steinmann pin or Denham pin is inserted below the tibial tuberosity and is inserted from the lateral to the medial side. Denham pin is threaded in the middle for better cortical hold.
The stirrup is attached and the cord is tied to distal weights. Again using various combinations of splints, proximal tibial traction can be modified to achieve the desired results.
Both, the distal femur and proximal tibia pin traction do not control rotational alignment.
Distal Tibial Traction
This is used in fractures distal to the knee such as Upper tibial fractures.
The pin is inserted about 5 cm proximal to the ankle joint from the medial to the lateral direction to protect the posterior tibial artery.
This is used for fractures of the tibia in the middle and distal third region. The pin is inserted from medial to lateral to avoid injury to the posterior tibial neurovascular bundle which sits posteroinferiorly to the medial malleolus.
A line is drawn from the tip of the medial malleolus to the tip of the calcaneum. The distance is divided into 4 parts. The entry is the junction of one-fourth distance from the tip of the calcaneum and three-fourths from the medial malleolus.
Potential risk includes damage to the medial calcaneal nerve and stiffness of the subtalar joint.
Olecranon and other upper limb skeletal tractions are rarely used now because of better surgical methods available and better implant dynamics. Early surgery allows ambulation and mobilization and that prevents joint stiffness.
Olecranon traction is mainly used for fracture of the distal end of the humerus and shaft of the humerus.
A sturdy K-wire or cancellous screw is inserted about 3 cm distal to the tip of the olecranon.
The K-wire is passed medial to lateral perpendicular to the longitudinal axis of the ulna and connected to the traction setup.
Metacarpal skeletal traction is used rarely nowadays.
For metacarpal traction, K-wire is passed 2.5 cm proximal to the metacarpophalangeal joint. They were used for forearm fractures and distal radius fractures.
Care and Complications of Skeletal Traction
Most of the complications unique to skeletal traction are due to the insertion of the pin.
These are quite rare but can happen. The injury can occur to the vessel or nerve in the vicinity. If it occurs appropriate measures for arterial or nerve injuries should be taken.
The aid of fluoroscopy to mark the direction and the pin can reduce the risk.
Thermal necrosis of the bone can occur if high-speed drills are used to pierce and advance the pin in the bone and should be avoided.
Insertion of the pin causes a breach in the skin and bone. Moreover, it creates a conduit for infections to travel from the surface to the bones.
An intraarticular pin can lead to septic arthritis.
It is best to prevent the infection. The pins need frequent cleaning to drain any accumulated fluid. There should not be any crust or adhesion of the tissue to the pin and one should be able to move the skin pin interface. chlorhexidine swabbed gauze or sponge should be placed around the pin site and the pin should be regularly monitored.
Superficial infection is tackled with aggressive cleaning and antibiotics. Often oral antibiotics are enough.
Deep infections may require iv antibiotics.
Infection that results in osteomyelitis or loosening of pin warrants pin removal.
The insertion of a pin creates cortical defects that act as stress risers to the bone and may lead to fractures. The pins inserted in proper sites reduce the chances of this. This is a unique complication of skeletal traction.
Stiffness and Joint Contracture
The limb on the traction needs to be exercised for individual joint motion otherwise stiffness and joint contractures may occur.
Therefore, a regular exercise schedule should be explained to the patient and monitored. The patient should be regularly evaluated for joint motion and suppleness.
Premature Physeal Closure
Premature physeal closure in children can occur if the pin inserted for skeletal traction causes injury to the physis or the infection causes damage to the physis.
Obey MR et al, Lower-Extremity Skeletal Traction Following Orthopaedic Trauma, JBJS Reviews: November 2019 – Volume 7 – Issue 11 – p e4 doi: 10.2106/JBJS.RVW.19.00032 [Abstract]