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

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.

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

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

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

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

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?

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

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

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

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

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

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?

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

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

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. 1993 Nov;75(6):921-5.

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

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

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

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

Reamer design Suction-irrigation reamer

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

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

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

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?

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

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)

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

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