Orthopedic Teaching Cases 2023, Jan, 20 | 12:00 am

tension band wire construct

You are consulted to evaluate the right elbow of a 38-year-old female who was involved in a motor vehicle collision earlier in the day. History reveals that she is left-hand–dominant and that she works as a chemistry professor at a local university. Physical examination demonstrates significant swelling about the left elbow with

abrasions posteriorly about the olecranon but no deep open wounds. She is unable to actively extend her elbow and has significant pain with passive elbow range of motion. Imaging shows a displaced transverse fracture of the olecranon. Pre- and postoperative lateral radiographs of the elbow are shown in Figure 6–13A and B, respectively.

 

 

 

Figure 6–13 A–B

 

What is the mechanical basis for this method of fracture fixation?

  1. Absolute stability of the fracture is achieved through multiple points of rigid fixation.

  2. There is controlled distraction of the fracture at the articular surface with elbow extension.

  3. The construct acts as an internal splint providing relative stability of the fracture at the articular surface allowing for secondary bone healing.

  4. Conversion of the triceps extensor force to a dynamic compressive force at the articular surface during elbow flexion.

Discussion

The correct answer is (D). A tension band wire (TBW) construct achieves static fixation dorsally with dynamic compression at the articular surface allowing for primary bone healing. Tension band wiring can be done where there are clear tension and compression surfaces of a bone, such as the olecranon or the patella and can use either K-wires or screws in combination with wire or a robust suture. The concept involves tensioning the wire (or suture) over the tension surface of a bone such that the distracting forces exerted on that surface are then converted to compressive forces on the opposite side.

What is the most important technical factor in preventing K-wire migration (backing out) when using a TBW construct?

  1. Ensuring proximal bent wire ends are buried beneath the triceps fibers

  2. Proper tensioning of the wire knots on either side of the construct

  3. Achieving bicortical purchase with the K-wires

  4. The quality of the articular surface reduction

 

Discussion

The correct answer is (A). While bicortical purchase does improve fixation, the most important factor is burying the proximal wire ends beneath the triceps. There is also risk associated with overpenetration of the anterior ulnar cortex, where the AIN and ulnar artery are in close proximity, and the proximal radioulnar articulation is potentially violated. While TBW constructs are very successful in achieving fracture union, with rates higher than 90% reported in the literature, they are frequently irritating and require removal of hardware for this reason after fracture healing as often as 33% to 80% of the time.

Which of the following would be a contraindication to using a tension band wire (TBW) construct to fix an olecranon fracture?

  1. A transverse fracture pattern

  2. The presence of fracture comminution

  3. An open fracture of the olecranon

  4. A short oblique fracture which does not extend past the midpoint of the trochlear notch

Discussion

The correct answer is (B). Comminution is a contraindication for the use of a tension band wire construct due to the potential to overcompress and cause narrowing of the greater sigmoid notch. A TBW also risks inadequate stabilization of the fracture in the setting of comminution. Mild to moderate comminution is an indication for plate fixation, as is the presence of articular fragment impaction. Another indication for plate fixation is a long oblique fracture which extends past 50% of the greater sigmoid notch, as these fractures are poorly controlled with a TBW construct.

What is the preferred treatment of a severely comminuted fracture of the olecranon where achieving a congruent joint surface is unlikely to be achieved with internal fixation?

  1. Splinting or casting in 45 to 90 degrees of flexion and neutral forearm rotation until early fracture consolidation

  2. A bridge plate construct over the defect/comminution to promote secondary bone healing

  3. Total elbow arthroplasty with reattachment of the triceps to the implant

  4. Fragment excision with triceps advancement

 

Discussion

The correct answer is (D). The primary goal in fixation of an olecranon fracture is to achieve a congruent joint surface. When this is not possible due to severe comminution of the fracture or due to bone loss, and also in some less severely comminuted cases involving elderly individuals with lower demands, excision of the proximal olecranon fragment with advancement of the triceps tendon is an acceptable treatment option. It has been suggested in the literature that as much as 50% to 75% of the olecranon articular surface can be excised without leading to gross elbow instability, provided that the coronoid process remains intact. Even when the triceps tendon is reattached in a dorsal position on the remaining olecranon to maximize triceps extension strength, it is reported that at least 24% of extension strength is lost.

 

Objectives: Did you learn...?

 

 

Indications for and potential complications with the use of tension band wiring? Technical considerations in creating a tension band wire construct?

 

When the use of plate and screw fixation or fragment excision is appropriate?