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OTA Comprehensive Fracture Course for Residents
MODULE FACULTY, PRINCIPLES, AND SCHEDULES
DIAPHYSEAL MODULE
Principles:
Primary/Secondary Bone Healing
1. Primary and secondary bone healing are different, but equal in value in achieving fracture union.
2. Internal fixation of fractures alters the biology of fracture healing.
3. Primary bone healing occurs through Haversian remodeling. A tip of osteoclasts drills a tunnel into
dead bone. Behind the tip, osteoblasts for new bone.
4. Primary bone healing occurs with absolute stability techniques.
5. Absolute stability techniques include lag screw with neutralization plate or compression plating.
6. Secondary bone healing occurs through callus.
7. Stages of secondary bone healing are inflammation, soft callus, hard callus, remodeling.
8. Secondary bone healing occurs with relative stability techniques.
9. Relative stability techniques include external fixation, intramedullary nailing, and bridge plating.
10. Vascular supply to the callus derives from surround soft tissue, so strip only what is
necessary.
11. Complex multifragmentary fractures tolerate more motion between the fragments
than simple ones.
12. Strain conditions taken into account when judging whether bony bridging or
nonunion will occur.
Intramedullary Nailing
13. Intramedullary nailing is a form of relative stability.
14. In the lower extremity, exact anatomical reconstruction of diaphysis is not required
for normal limb function. Restoration of correct length, axis, and rotation are
necessary.
15. Intramedullary nail fit is good in diaphysis, poor in metaphysis. Placement of the nail
will not assist in metaphyseal reduction.
16. Techniques to hold reduction in metaphyseal fractures being treated with
intramedullary nailing include unicortical plates and screws, clamps, or external
fixator.
17. Strength of nail proportional to fourth power of radius of implant.
18. Slotted nails have less rotational strength than non-slotted nails.
19. Reaming allows placement of larger implant in the intramedullary canal.
20. Working length is distance between proximal point of good contact between nail and bone and
distal point of good contact between nail and bone. Bending strength is related to the inverse of
working length.
21. Nails without interlocking screws are unlocked nails. Nails with interlocking screws proximal and
distal to the fracture are locked statically when the interlocking screws are placed in static holes.
Nails can be locked dynamically by placing one interlocking screw in a dynamic [elongated] hole on
one side of the fracture (stable in rotation but less so in length) or by not placing an interlocking
screw on one side of the fracture (unstable in rotation and length).
22. Damage occurs to the endosteal blood supply of the bone with reaming. This is reversible.
23. Design of reamers influences intramedullary pressure and temperature.
24. Starting points for nailing can be off-axis, or in line with the intramedullary canal
(retrograde femur).
25. Off-axis starting points are eccentric to the intramedullary canal (i.e. off the anatomic axis which is
the center/center position of the intramedullary canal) (e.g. tibia).
Plating Mechanics
26. Absolute stability reduces strain at fracture site and allow for direct bone healing.
27. A lag screw provides compression across a fracture, which increases friction and
decreases motion at the fracture site.
28. Lag screw should be perpendicular to plane of the fracture to get compression without sliding of
the fracture fragments.
29. To act as a lag screw the cortex screw requires a gliding hole in the near cortex.
30. A lag screw cannot resist axial loading, bending and torsional forces well over time.
31. Locked screw heads screw into opposing threads on plate hole. Locked plating occurs in different
mechanical forms though (e.g. caps which screw onto the screw head, etc). This is dependent upon
the implant design.
32. Lag or position screws should be placed before locking screws.
33. A plate’s job depends on how you use it and is not defined by design.
34. A neutralization plate will resist axial loading, bending and torsional forces around a fracture,
protecting the lag screw.
35. A bridge plate spans the fracture with screws proximal and distal to the fracture. Individual fracture
fragments are not always exposed or reduced. Rather than an anatomic reduction (perfect
apposition of all fragments), the goal is to achieve length, alignment, and rotation.
36. Compression plating uses the design of the plate to achieve compression across the fracture.
Plating with compression can occur by using adjunctive techniques that do not rely on the plate
holes [e.g. articulated tensioning device, clamp placed into hole of plate and around screw outside
of plate, universal distractor placed in compression mode, etc.)
37. Articular fractures require anatomical reduction and stable fixation.
38. In the forearm anatomical reduction is typically chosen to improve the chances of good function by
recreating the radial bow and the relative lengths of the radius and ulna.
Failed Fixation
39. Loosening of cortical and cancellous screws is induced by micromotion.
40. Locked constructs fail catastrophically.
41. Nonunion is often defined as fracture that has not healed with sequential observation over a
prolonged period, and likely requires intervention to get it to heal.
42. Treatment of nonunions is highly individualized.
43. Thoughtful approach to why nonunion occurred is helpful in determining a treatment plan that will
address all factors.
44. Be suspicious for infection in any nonunion.
45. Atrophic nonunions occur because of inadequate blood supply. Techniques to treat atrophic
nonunions involve introducing biology to the nonunion site.
46. Hypertrophic nonunions occur because of excessive motion at the fracture site. Techniques to treat
hypertrophic nonunions involve stabilizing the fracture.
47. In an infected nonunion, devitalized bone is a sequestrum and must be removed.
Schedule:
Lectures/Case Presentations (30 minutes each): THESE ARE ALL COVERED IN THE PRECOURSE LECTURE
VIDEOS. APPLICATION OF THE PRINCIPLES THROUGH CASE DISCUSSIONS OR QUESTIONS WOULD BE
EXCELLENT TO ENSURE THEY ANALYZE, REFLECT UPON, AND TRY TO APPLY WHAT THEY LEARNED IN
THE PRECOURSE SECTION
1. Primary bone healing vs. Callus
2. Intramedullary nail mechanics
3. Plate mechanics
4. Failed fixation
Labs
1. Intramedullary nailing proximal tibia fracture
2. Open reduction internal fixation forearm fracture
Sequence
1. Primary bone healing vs. Callus lecture/case presentation 30 minutes
2. Intramedullary nailing mechanics lecture/case presentation 30 minutes
3. Intramedullary nailing proximal tibia laboratory 45 minutes
Simple proximal tibial model without soft tissue envelope
Infrapatellar approach
provide plate/unicortical screws as well as clamps for reduction tools
sure-shot for simulated interlocking screw placement 4. Break 15 minutes
5. Plate mechanics lecture/case presentation 30 minutes
6. Plating lab 45 minutes
lag screw/compression plating radius
bridge plating ulna
7. Failed Fixation lecture/case presentation (Probe) 30 minutes
8. Break 15 minutes