Nails and rods are intramedullary (IM) fixation devices for long bones that have varying definitions from different sources with no uniform definition
IM nail (IMN): variably described as
Rigid, straight, hollow IM device
Has proximal and distal holes to allow locking into place
Driven into position by specialized tool
Requires reaming of marrow cavity to allow placement
IM rods: variably described as
Solid IM device; may be curved &/or flexible
No interlocking function
Does not require reaming or specific driver
In general, wide-bore IM device that nearly fills marrow space at midportion = IMN; narrow device that is often used in multiples = rod
Antegrade placement: placed from proximal end of bone to distal end of bone; most common direction of insertion
Retrograde placement
Placed in distal aspect of bone and directed proximally
Indications for retrograde insertion in femur
Distal femur fractures to achieve better control/reduction
Obese patients in whom entry point in proximal femur will be difficult to reach
Polytrauma patients to minimize surgical time
Concepts of Nail/Rod Placement and Use
Used to treat long bone fractures
Share load, allowing for early weight bearing
Unlocked and dynamic locking allow micromotion, which stimulates healing
Insertion with minimal soft tissue dissection compared to plates
Antegrade vs. retrograde determined by site of fracture, ease of access to desired entry site
Removed after healing achieved in children/young adults
Static locking
Rod locked at proximal end and distal ends
Provides axial and rotational stability
Allows immediate weight bearing
Risk is overdistraction, which can lead to delayed healing
Used for unstable fractures
Prevents collapse at fracture, which could lead to limb-length discrepancy
Dynamic locking
Interlocking screw, locked at 1 end only
To dynamize means to remove 1 set of screws of static (proximal and distal) locked rod
Dynamizing allows natural compression across fracture to promote healing
Used for transverse or shallow oblique fractures with minimal comminution
Reaming: removing IM contents to allow passage of IMN, appropriate size of tunnel
Reamed nails usually larger, provide greater stability
May ↑ risk of fat embolism
Provides degree of natural bone graft at fracture site
Disrupts internal blood supply, ↑ infection risk
Flexible rod: Ender, Lottes
Used in immature skeleton to avoid growth plate
Less rigid; may require additional stabilization, such as splint/cast
Usually place multiple rods via multiple entry sites in metaphysis
Usually leave small portion outside bone to enable subsequent retrieval
Cephalomedullary nail (CMN)
Femoral IMN coupled with fixed-angle device that extends up femoral neck into head
Component for head: large screw, 2 smaller screws, or spiral blade
Larger screw may function similar to dynamic hip screw
Currently used for most peritrochanteric fractures
"Gamma nail" was original CMN; no longer in use today
Short and long versions exist
Lengthening nail
IMN devised to combine with osteotomy/corticotomy to lengthen bone
Uses external magnets to elongate nail
In setting of congenital or posttraumatic limb shortening
Fusion nail
Long version in use to fuse knee; extends from proximal femur to distal tibia
Hindfoot nail: short IMN to fuse hindfoot and ankle, inserted retrograde
IMAGING
General Features
Radiographic Findings
CT Findings
MR Findings
CLINICAL ISSUES
Presentation
Selected References
Hosny GA: Limb lengthening history, evolution, complications and current concepts. J Orthop Traumatol. 21(1):3, 2020
Poutoglidou F et al: Flexible intramedullary nailing in the treatment of forearm fractures in children and adolescents, a systematic review. J Orthop. 20:125-30, 2020
Gausden EB et al: Biomechanics of periprosthetic fixation: plates, nails, cables, and allografts. J Orthop Trauma. 33 Suppl 6:S1-4, 2019
Hake ME et al: Modern implant options for the treatment of distal femur fractures. J Am Acad Orthop Surg. 27(19):e867-75, 2019
Allen H et al: Orthopaedic fixation devices used in children: a radiologist's guide. Semin Musculoskelet Radiol. 22(1):12-24, 2018
Virkus WW et al: Intramedullary nailing of periarticular fractures. J Am Acad Orthop Surg. 26(18):629-39, 2018
Horwitz DS et al: Nail length in the management of intertrochanteric fracture of the femur. J Am Acad Orthop Surg. 24(6):e50-8, 2016
Georgiannos D et al: Subtrochanteric femoral fractures treated with the long Gamma3 nail: a historical control case study versus long trochanteric Gamma nail. Orthop Traumatol Surg Res. 101(6):675-80, 2015
Queally JM et al: Intramedullary nails for extracapsular hip fractures in adults. Cochrane Database Syst Rev. 9:CD004961, 2014
Study to prospectively evaluate reamed intramedullary nails in patients with tibial fractures investigators et al: randomized trial of reamed and unreamed intramedullary nailing of tibial shaft fractures. J Bone Joint Surg Am. 90(12):2567-78, 2008
Gadegone WM et al: Proximal femoral nail - an analysis of 100 cases of proximal femoral fractures with an average follow up of 1 year. Int Orthop. 31(3):403-8, 2007
Wood GW 2nd: Intramedullary nailing of femoral and tibial shaft fractures. J Orthop Sci. 11(6):657-69, 2006
Related Anatomy
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Related Differential Diagnoses
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References
Tables
Tables
KEY FACTS
Terminology
Imaging
Clinical Issues
TERMINOLOGY
Definitions
Nails and rods are intramedullary (IM) fixation devices for long bones that have varying definitions from different sources with no uniform definition
IM nail (IMN): variably described as
Rigid, straight, hollow IM device
Has proximal and distal holes to allow locking into place
Driven into position by specialized tool
Requires reaming of marrow cavity to allow placement
IM rods: variably described as
Solid IM device; may be curved &/or flexible
No interlocking function
Does not require reaming or specific driver
In general, wide-bore IM device that nearly fills marrow space at midportion = IMN; narrow device that is often used in multiples = rod
Antegrade placement: placed from proximal end of bone to distal end of bone; most common direction of insertion
Retrograde placement
Placed in distal aspect of bone and directed proximally
Indications for retrograde insertion in femur
Distal femur fractures to achieve better control/reduction
Obese patients in whom entry point in proximal femur will be difficult to reach
Polytrauma patients to minimize surgical time
Concepts of Nail/Rod Placement and Use
Used to treat long bone fractures
Share load, allowing for early weight bearing
Unlocked and dynamic locking allow micromotion, which stimulates healing
Insertion with minimal soft tissue dissection compared to plates
Antegrade vs. retrograde determined by site of fracture, ease of access to desired entry site
Removed after healing achieved in children/young adults
Static locking
Rod locked at proximal end and distal ends
Provides axial and rotational stability
Allows immediate weight bearing
Risk is overdistraction, which can lead to delayed healing
Used for unstable fractures
Prevents collapse at fracture, which could lead to limb-length discrepancy
Dynamic locking
Interlocking screw, locked at 1 end only
To dynamize means to remove 1 set of screws of static (proximal and distal) locked rod
Dynamizing allows natural compression across fracture to promote healing
Used for transverse or shallow oblique fractures with minimal comminution
Reaming: removing IM contents to allow passage of IMN, appropriate size of tunnel
Reamed nails usually larger, provide greater stability
May ↑ risk of fat embolism
Provides degree of natural bone graft at fracture site
Disrupts internal blood supply, ↑ infection risk
Flexible rod: Ender, Lottes
Used in immature skeleton to avoid growth plate
Less rigid; may require additional stabilization, such as splint/cast
Usually place multiple rods via multiple entry sites in metaphysis
Usually leave small portion outside bone to enable subsequent retrieval
Cephalomedullary nail (CMN)
Femoral IMN coupled with fixed-angle device that extends up femoral neck into head
Component for head: large screw, 2 smaller screws, or spiral blade
Larger screw may function similar to dynamic hip screw
Currently used for most peritrochanteric fractures
"Gamma nail" was original CMN; no longer in use today
Short and long versions exist
Lengthening nail
IMN devised to combine with osteotomy/corticotomy to lengthen bone
Uses external magnets to elongate nail
In setting of congenital or posttraumatic limb shortening
Fusion nail
Long version in use to fuse knee; extends from proximal femur to distal tibia
Hindfoot nail: short IMN to fuse hindfoot and ankle, inserted retrograde
IMAGING
General Features
Radiographic Findings
CT Findings
MR Findings
CLINICAL ISSUES
Presentation
Selected References
Hosny GA: Limb lengthening history, evolution, complications and current concepts. J Orthop Traumatol. 21(1):3, 2020
Poutoglidou F et al: Flexible intramedullary nailing in the treatment of forearm fractures in children and adolescents, a systematic review. J Orthop. 20:125-30, 2020
Gausden EB et al: Biomechanics of periprosthetic fixation: plates, nails, cables, and allografts. J Orthop Trauma. 33 Suppl 6:S1-4, 2019
Hake ME et al: Modern implant options for the treatment of distal femur fractures. J Am Acad Orthop Surg. 27(19):e867-75, 2019
Allen H et al: Orthopaedic fixation devices used in children: a radiologist's guide. Semin Musculoskelet Radiol. 22(1):12-24, 2018
Virkus WW et al: Intramedullary nailing of periarticular fractures. J Am Acad Orthop Surg. 26(18):629-39, 2018
Horwitz DS et al: Nail length in the management of intertrochanteric fracture of the femur. J Am Acad Orthop Surg. 24(6):e50-8, 2016
Georgiannos D et al: Subtrochanteric femoral fractures treated with the long Gamma3 nail: a historical control case study versus long trochanteric Gamma nail. Orthop Traumatol Surg Res. 101(6):675-80, 2015
Queally JM et al: Intramedullary nails for extracapsular hip fractures in adults. Cochrane Database Syst Rev. 9:CD004961, 2014
Study to prospectively evaluate reamed intramedullary nails in patients with tibial fractures investigators et al: randomized trial of reamed and unreamed intramedullary nailing of tibial shaft fractures. J Bone Joint Surg Am. 90(12):2567-78, 2008
Gadegone WM et al: Proximal femoral nail - an analysis of 100 cases of proximal femoral fractures with an average follow up of 1 year. Int Orthop. 31(3):403-8, 2007
Wood GW 2nd: Intramedullary nailing of femoral and tibial shaft fractures. J Orthop Sci. 11(6):657-69, 2006
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