Fracture Healing (including nonunion)

Radiographic findings may include:

  • a linear or curvilinear decreased density dividing a bone into two or more segments
    • ill-defined margins or well-defined with or without sclerotic margins
  • periosteal reaction (ill-defined, fluffy, or well-defined)

Podcast

The following enhanced podcast includes images. Save it to your computer (right-click→Save As...). (Left-clicking on the podcast link will only play the audio portion with no images.)

Here are presentations of fracture healing and related pathology (with *interpretations):

  • Case 1
  • *Case 1
  • Case 2
  • *Case 2
  • Case 3
  • *Case 3
  • Case 4a
  • *Case 4a
  • *Case 4b
  • Case 5a
  • Case 5b
  • *Case 5a
  • *Case 5b
  • Case 6
  • *Case 6
  • Case 7
  • *Case 7
  • Case 8
  • *Case 8
  • Case 9
  • *Case 9
1 Fracture Healing 1 2 Fracture healing 2 3 Fracture healing 3
1 Fracture healing 1 marked 2 Fracture healing 2 marked 3 Fracture healing 3 marked

Dorsoplantar views.
1) At the initial injury, a faint, linear decreased density runs across the third metatarsal distal metaphysis; discontinuity is visible along the lateral aspect.
2) Approximately three weeks later, ill-defined and fluffy periosteal reaction is seen at the fracture margins; additionally, bone resorption has occurred within the fracture site, which makes the fracture line appear more visible. There has been no gross change in positioning of the fracture segments relative to one another.
3) Approximately eight weeks after the initial study, there has been remodeling of the periosteal reaction that was seen in the second study; it is now well-defined, and no evidence of discontinuity is evident.
Diagnosis: 1) impaction fracture third metatarsal; 2) fracture healing; 3) fracture healed.

1 Nonunion fracture serial 1 2 Nonunion fracture serial 2
1 Nonunion fracture serial 1 marked 2 Nonunion fracture serial 2 marked

Dorsoplantar views.
1) At 5 weeks postop, findings include a curvilinear, somewhat ill-defined decreased density (arrowheads) running transversely across the first metatarsal proximal one-third diaphysis. It is surrounded by exuberant and fluffy periosteal new bone (P), which is a result of movement at the osteotomy site. Other findings (when compared to the preop study, which is not provided) include absence of the first metatarsal medial eminence as well as the hallux proximal phalanx proximal one-half; in its place is a semi-opaque implant device; the stem is not fully within the remaining diaphysis, and the articular surface does not fully appose the metatarsal head.
2) At one-year postop, the periostitis (P) is now remodeled and well-defined. However, there is also a fairly well-defined, linear decreased density with sclerotic margin running across the osteotomy site.
Diagnosis: 1) bunionectomy with hemiphalangectomy and silastic hemi-implant; 2) elephant foot hypertrophic nonunion of osteotomy.

1 Fracture "bridging" 2 fracture "bridging" 2
1 fracture "bridging" 1 marked 2 fracture "bridging" 2 marked

1) Dorsoplantar and 2) medial oblique views, same date.
Beware when looking for trabecular or cortical "bridging" to assess fracture healing. What appears to be bony "bridging" in the dorsoplantar view is actually superimposition due to the x-ray beam not being tangent to the fracture line. There is clearly no evidence of union in the medial oblique view. These images were obtained 16 weeks post injury, and the fracture eventually resulted in nonunion. Diagnosis: delayed union (based upon the number of weeks post injury).

midshaft nonunion postop
nonunion postop marked

Dorsoplantar view.
This image was obtained approximately one year after the surgery was performed. The osteotomy margins are well-defined and bounded by sclerotic margins (arrowheads). Diagnosis: horse hoof hypertrophic nonunion.

bone scan nonunion

Bone scintigraphy, 3rd phase ("bone scan"), anterior and medial images.
This study is from a different patient, but demonstrates what might be seen if ordered on this patient. The arrows point to the osteotomy site, which displays less uptake than seen at the periphery of the osteotomy both proximal and distal to it.

pseudarthrosis dp view
pseudarthosis lateral view
pseudarthrosis dp view marked

Dorsoplantar view.
A fairly well-defined, linear decreased density runs across the second metatarsal middle one-third diaphysis. This is surrounded by scrotic margins (S) centrally and well-defined, remodeled periosteal reaction at the periphery. (See *Case 5b for diagnosis.)

pseudarthrosis lateral view marked

Lateral view.
As in the dorsoplantar view (*Case 5A), a fairly well-defined, linear decreased density runs through the second metatarsal middle one-third diaphysis. A sclerotic margin (S) is also evident. However, upon clinical examination, there was some sagittal plane motion between the two segments; notice the signifiant angulation between them.
Diagnosis: pseudarthrosis, horse hoof hypertrophic nonunion.

1 malunion tibia 2 bone scan tibia 3 bone scan medial leg
1 malunion tibia marked 2 bone scan marked 3 bone scan 2 marked

1) Mortise view and 2-3) bone scintigraphy (third phase bone scan).
1) There is apparent osseous union between the distal and proximal tibial segments (arrows). Notice the gross lateral displacement and slight medial angulation of the distal segment relative to the proximal.
2-3) A bone scan was obtained to verify osseous union. The anterior and medial images demonstrate focal uptake at the the fracture site (white line).
Diagnosis: malunion fracture, tibia.

horse hoof nonunion
horse hoof nonunion marked

Medial oblique view.
There is an oblique, well-defined decreased density running through the distal metaphysis of the fibula. A sclerotic margin (S) is evident as is remodeled periosteal reaction or bone callus (c).
Diagnosis: horse hoof hypertrophic nonunion.

oligotrophic nonunion
oligotrophic nonunion marked

Dorsoplantar view.
This patient sustained an avulsion fracture of the 5th metatarsal years before this image was obtained. Finding include well-defined margins with little evidence of bone production.
Diagnosis: oligotrophic hypertrophic nonunion.

defect nonunion
defect nonunion markled

Dorsoplantar view.
This patient had a portion of the distal one-third diaphysis removed many years prior to this image. The margins of bone are well-defined. There is no evidence of bone production; in fact, the bone ends are tapered and separated from one another.
Diagnosis: atrophic, defect nonunion.

Should a radiographic study be ordered to assess fracture healing?

Definitely yes. Generally speaking, if the patient's progress has been unremarkable clinically, then images can be obtained at monthly intervals. However, if there has been anything out of the ordinary (unusual amount of pain, reinjury, signs of infection, for example), then images should be obtained immediately.

What are the best views to order?

At a minimum order DP (or AP & mortise, if ankle) and lateral views. Oblique views are not necessary but can be valuable when evaluating the following anatomic area:

  • calcaneus: medial and lateral obliques
  • talus: medial oblique
  • ankle joint: medial oblique

CT may be necessary for pathology that is inconclusive on plain films.

Other information

Bone scintigraphy can be valuable for distinguishing between delayed union and nonunion.

References:

  1. Christman RA: Foot and Ankle Radiology, 2nd edition, Lippincott Williams & Wilkins, 2015.