Fractures of the olecranon and the patella Published: July 2013 Brian Bernstein, ZA AOT Basic Principles Course

Learning outcomes Explain the tension band principle for fractures of the olecranon and patella Discuss the limitations and complications of tension band wiring (TBW) Describe surgical techniques used in the treatment of patellar and olecranon fractures Define alternative techniques when TBW is not possible

Tension band situation Force applied eccentrically causes tension and compression within the column Tension absorbed/converted by a band Compression absorbed by a strong buttress

Tension band principle “In relation to long bones there is generally a tension side and a compression side.” Pauwels

Tension band principle Conversion of the tensile forces across a fracture into compressive forces Fixation device placed eccentrically on tension side of fracture If we understand the biomechanical principle described by Pauwels in relation to the tension and compression sides of a long bone, and apply this to areas of eccentric muscle action, we will understand the principle behind the tension band wire.

Tension band principle Dynamic or static (“dynamic” absolute stability) Articular fractures where muscle pull will distract the fragments Avulsion fractures Diaphyseal fractures where there is a tension and compression side The application of a tension band to a mobile part of the body confers neither absolute nor relative stability, rather a form of “dynamic” absolute stability whereby contraction causes resultant compression at the fracture site.

How does it work?

What does this mean We can convert destructive forces into constructive forces

Indications Olecranon (dynamic) Patella (dynamic) Tuberosity of humerus (dynamic) Medial and lateral malleoli (dynamic) Trochanter of femur (dynamic) Diaphyseal fractures (static) Common areas where principle applies.

Tension band construct External fixation applied on the tension side of a bone will act as a tension band construct.

Exo / plate

Greater tuberosity Tension band application applying compression to a greater tuberosity fracture

Olecranon and patellar fractures Treatment goals Restoration of articular surface Preservation of power of extension Joint stability Preservation of range of movement Avoidance of complications

Olecranon and patellar fractures Conservative treatment Undisplaced fractures, ie, articular separation < 2 mm No displacement with flexion Active extension BUT: Articular fractures are best treated with absolute stability

Tension band principle

Classification of displaced olecranon fractures AO Müller Schatzker

Olecranon fractures Recent development of anatomical locking plates Tension band wire (TBW)

Olecranon Conversion by TBW

Parallel K-wires Tension on both sides of the band Secure medial buttress

Displaced olecranon—transverse fractures 43-year-old, slipped on ice

Displaced olecranon—oblique fractures Primary fixation with interfragmentary lag screw and supplementary TBW

Displaced olecranon—complex fractures Require tension band plate—one-third tubular/reconstruction plate/locking plate

Displaced olecranon—complex fractures 54-year-old, fell off ladder One-third tubular plate cut at a hole to make spikes

Displaced olecranon—complex fractures One-third tubular plate Additional TBW

Displaced olecranon—complex fractures 29-year-old, motorcycle accident Reconstruction plate

Displaced olecranon—complex fractures Reconstruction plate Postoperative

Displaced olecranon—complex fractures 6 months: Full rotation Full flexion 20°extension Normal function

Displaced olecranon—complex fractures 80-year-old woman Complex and osteoporotic

Anatomical locking plate

Displaced olecranon fractures Management depends on fracture pattern Simple transverse—TBW Simple oblique—TBW + lag screw Complex—tension band plate (locking) + TBW Multifragmentary involving dorsal cortex Fracture distal to articular surface Fracture dislocation

Patellar fractures Articular fractures Part of the quadriceps mechanism Complex fractures may require patellectomy

Patellar fractures

Patellar fracture classification

Patella The tension band principle applies in the same manner as for the olecranon, by converting the distraction force when contracting the quadriceps muscle in dynamic compressive force across the fracture.

TBW using two K-wires Early AO manual operative description.

Displaced patellar fractures

Displaced patellar—transverse, simple fractures 39-year-old, tripped

Displaced patellar—transverse, simple fractures 39-year-old, tripped

Displaced patellar fractures—multifragmentary (stellate)

Displaced patellar fractures—multifragmentary (stellate)

Displaced patellar fractures—multifragmentary (stellate) Alternative fixation with cannulated screws and associated tension band applied through screws.

Displaced patellar fractures—multifragmentary (stellate) 47-year-old, fell on steps

Special application distal pole fractures

Distal pole patellar fractures—repair of patella tendon support

TBW supporting tendon repair

Displaced patellar fractures—partial patellectomy

Displaced patellar fractures Total patellectomy < 25% good/excellent result Preservation of one quarter will improve results References: Scott JC. Fractures of the patella. J Bone Joint Surg Br. 1949 Feb;31B(1):76-81 Einola S, Aho AJ, Kallio P. Patellectomy after fracture. Long-term follow-up results with special reference to functional disability. Acta Orthop Scand. 1976 Aug;47(4):441-7. Wilkinson J. Fracture of the patella treated by total excision. A long-term follow-up. J Bone Joint Surg Br. 1977 Aug;59(3):352-4.

Take-home messages Tension band fixation is a technique not a device and the device required depends upon the fracture type. TBW is recommended for simple transverse fractures, although additional lag screws/cerclage wires will extend its indications. Complex fractures require alternative techniques: Tension band plate Partial patellectomy Avoid total patellectomy