1. Intramedullary nailing—to ream or not to ream?
Published: September 2013
Bob Vander Griend, US
AOT Basic Principles Course

2. Learning outcomes Discuss the benefits and drawbacks of reaming
Discuss the benefits and drawbacks of intramedullary (IM) nailing without reaming
Teaching points:
Describe the advantages of the newer generation reamers and other techniques to decrease thermal and pressure effects of reaming.

3. Objectives Why ask this question? Historical background
What happens when you ream?
Pathophysiology of IM reaming
What should I do?
Clinical application of available data

4. Gerhardt Kuntscher (1900–1972)
“Preserve” periosteal vascularity
Indirect reduction
IM reaming
“Elastic nailing” and “tight fit”
Cloverleaf nail

5. IM reaming  IM canal diameter  IM nail diameter (stronger nail)
“The nail must be wide enough to occupy the entire cross section of the medullary canal over its entire length” G Kuntscher
 IM canal diameter
 IM nail diameter (stronger nail)
 working length
 fixation stability
Axial forces
Rotation
Bending

6. Interlocked nailing (1980s)
Multi-plane stability
No need for
Large diameter, tight fitting nails
“Extensive” reaming

7. Unreamed nails (1990s) Outcomes of unreamed nailing?
Interlocking techniques
Implants designed for nonreamed insertion
Initially for IM nailing of open fractures
Unreamed nail
Faster
Option to reduce fracture with nail
Less trauma to the bone and body?
Outcomes of unreamed nailing?

8. Pathophysiology of reaming
IM blood supply
Reaming and nail insertion
Elevation of IM pressure
Thermal injury
Effect on bone healing mechanisms

9. Blood supply to cortical bone
Inner 2/3 of cortex
Nutrient medullary artery
Outer 1/3 of cortex
Periosteum
Extra-osseous soft tissues

10. Any manipulation of the IM canal will affect the IM blood supply
Unreamed
Minimal reaming
Extensive reaming

11. Studies: Bone blood flow
Reaming technique
Type of IM fixation?
Technique of blood flow measurement?
Ultrasound
Laser doppler
Microspheres
Injection/perfusion
Histological
Different models
Rat, rabbit, dog
sheep, human
Which bone?
Femur
Tibia
Intact versus fracture model?
Extent of reaming?
Unreamed
Minimal reaming
Extensive reaming

12. Cortical blood flow decreased
unreamed
reamed
Cortical blood flow decreased
Unreamed bone ( 20%) Reamed bone ( 60%)
If nail diameter = canal diameter
there is minimal difference between reamed and unreamed

13. Initial perfusion recovery may be faster in unreamed nail
Compensatory  periosteal blood flow
Revascularization
Remodeling of bone over time
Does reaming have any long-term adverse effects on bone healing?

14. IM pressure IM canal manipulation causes  IM pressure Resting
30–60 mmHG
Opening of canal
200–300 mmHG
Guide wire/1st reamer
500–1000 mmHG
Sequential reaming
Variable
Nail insertion
200 to more than 1000 mmHG

15. Local effects:  IM pressure
Occlusion blood vessels
Efferent veins
Subperiosteal vessels
Debris  Haversian canals and vessels
Fat
Marrow
Bone
Compartment pressure effect?

16. Systemic effects:  IM pressure
Intraoperative trans-esophageal echo
No emboli—60%
Showers—25%
Large emboli—15%
Effect on:
Pulmonary function
Central nervous system?
References:
Pell AC, Christie J, Keating JF, et al. The detection of fat embolism by transoesophageal echocardiography during reamed intramedullary nailing. A study of 24 patients with femoral and tibial fractures. J Bone Joint Surg Br Nov;75(6):921-5.

17. Pulmonary effect Etiology (?): Contributing factors
Embolization
Biochemical
Contributing factors
Preexisting lung pathology
Coexisting lung trauma
ARDS versus FES
Other factors?
Contribution from  IM pressure?
Manipulation of bone (reduction)
Reaming
IM nail insertion

18. Long-bone fractures and lungs
Fixation of long bones beneficial
Effect of reaming and IM fixation
Minimal adverse effect on normal lungs
Effect on injured lungs—YES
Difficult to quantify pulmonary injury
Are there high risk patients? YES:
 Damage Control versus Immediate Total Care

19. Risk factors for  IM pressure
Canal contents (patient variability?)
↑↑ viscosity of metastatic disease
Reaming intact bone
Prophylactic nailing
Closed osteotomy
Infection
Intramedullary hip screw IMHS
Long (and/or narrow) isthmal segment?
  isthmal reaming for proximal/distal fracture

20. Risk factors for  IM pressure
Reamer mechanics
Sharp versus dull
Deep cutting flutes
Reamer head that clears debris
Shaft diameter << head (facilitate clearance)
Clearance
Reaming technique
Rotation speed (faster is better)
Sequential (increase reamer size by 5 mm)
Force of reaming: gentle insertion and removal

21. Reamer design
Suction-irrigation reamer

22. Thermal injury—bone death at 50º C
Same issues as with IM pressure
Tourniquet versus no tourniquet
Heat dissipation??
Solutions
Reamer design and utilization
Proper technique

23. Reaming effect: biological
Internal bone grafting?
Stimulation  blood flow?
Activates greater cellular/humoral response?
Does this enhance fracture healing?
Goal of fixation with IM nails is to achieve stable fixation resulting in indirect fracture healing with callus

24. Reaming effect: mechanical
Facilitates nail insertion
Nail insertion with minimal force
Facilitates use of larger implant
Improved implant mechanical properties: bending R3 torsion R4
Some locking options require a larger nail
Improved fixation stability

25. Unreamed nails Solid unreamed nails Mechanical properties affected by:
 nail diameter
Locking hole size related to nail diameter
 locking screw size
Solid unreamed nails
Better performance (?)
Fixation stability
Patient rehabilitation issues?

26. Clinical application of available data:
Unreamed versus reamed nailing
Multiple studies (more than 1,500 in English)
Most either unreamed or reamed nailing
Most are Level II or III studies
Some Level I studies (eg, SPRINT study)
Femur versus tibia

27. Conclusions from the literature:
Infection: open and closed fractures
No difference between unreamed versus reamed nails
Reamed nails better than unreamed nails
Time to union
Nonunion and delayed union
Reoperation
Implant problems
Femur (reamed nails superior in every study)
Tibia (reamed nails generally have a higher rate of healing)

28. Summary: reaming Increased fracture union with reamed nails
Better mechanical properties of larger implants
Many IM nail systems require reaming to use larger diameter nails with multidirectional locking options
Minimal adverse effects from limited reaming using proper reaming techniques and reamers
Contraindication to reaming also a contraindication to IM fixation

29. Take-home messages To ream or not to ream?
What implant do you want to use? Why?
Know
Advantages and disadvantages
Surgical techniques Do
Procedure(s) correctly
Appropriate aftercare