Radiology Packet 43

Equine Phalanges

3 yr old STDB Gelding

• HX = presented for an acute onset of lameness in the left fore that occurred immediately after racing, the horse is sensitive to hoof testers in the left fore foot

3 yr old STDB Gelding

3 yr old STDB Gelding

• RF

– In the DP view there is a linear lucency in the lateral aspect of P3, this line is approximately parallel to midline and is oriented in a different direction than the normal vascular channels.

– The DLPMO view provides better visualization of the lucent line.

– This line can be seen extending into the distal inter-phalangeal joint.

– The opaque material seen along the medial surface in the DP and DLPMO views is debris on the surface of the hoof.

• RD

– Articular fracture of the lateral aspect of P3 (Type II)

13 yr old Appaloosa Gelding“Joker”

• HX = history of right forelimb lameness and a noticeably large pastern

13 yr old Appaloosa Gelding“Joker”

13 yr old Appaloosa Gelding“Joker”

• RF– Marked narrowing of the proximal interphalangeal joint.

– Marked osteophyte formation around the dorsal, medial, and lateral margins of P1-2, involving the distal periarticular margins of P1 and the proximal margins of P2.

– The osteophytes extend well beyond the articular margins, to include the distal half of P1 and the proximal half of P2.

– Enthesophytes are noted along the palmar surface of mid P1, the site of distal suspensory ligamentous attachment.

– On the DP radiograph note the very mottled bone opacity of distal P1 due to the large amount of new bone.

• RD– Severe degenerative joint disease of the right front proximal interphalangeal joint, known as

high ringbone

– Since the bony reaction extends well beyond the articular margins and includes mid P2, non-articular ringbone is also present

2 yr old STDB Colt

• HX = grade 3 of 4 lame in the right hindlimb

2 yr old STDB Colt• RF

– There is a subchondral lucency in the proximomedial aspect of the middle phalanx.

– The lucent area is irregularly marginated and surrounded by sclerotic bone.– In the lateral view the lucent area is not seen as a distinct structure but there is

an appearance of mixed opacity in the dorsoproximal middle phalanx.– Careful evaluation (hotlight) shows an irregular periosteal response on the dorsal

aspect of the second phalanx which seems to be located at the distal margin of the lucent lesion.

• RD– Subchondral bone cyst of the proximal middle phalanx

• Next– Surgical curettage could be considered, however with a cyst in this location,

secondary osteoarthritis will likely occur and the prognosis for soundness is fairly poor.

4 yr old Grade Gelding“Bobby”

• HX = presented for evaluation of bilateral forelimb lameness

4 yr old Grade Gelding“Bobby”

• RF– The osseous structures of the right forelimb (left film) are normal in appearance.– In the left forelimb there is osteophyte formation at the extensor process of the

third phalanx (right film).

• RD– Degenerative joint disease (osteoarthritis) of the distal interphalangeal joint of the

left forelimb (low ringbone)

3 yr old Arabian Colt

• HX = presented for evaluation of a left forefoot lameness that has been going on for three weeks

3 yr old Arabian Colt• RF

– There is a large round lucency located centrally within the distal phalanx.– A sclerotic margin surrounds the area of lucency.– In the lateral view remodeling of the dorsoproximal third phalanx is evident.– This has resulted in change in shape of the extensor process and narrowing of

the distal interphalangeal joint dorsally.• RD

– Subchondral bone cyst of the third phalanx• Next

– Surgical curettage

1 yr old Belgian Filly“Candy”

• HX = the filly is grade 4 of 5 lame in the left hindlimb and has been for one month

1 yr old Belgian Filly“Candy”

• RF– There is a sibchondral lucency in the distomedial aspect of the proximal phalanx.– A rim of sclerotic bone surrounds the lucency.– In the DP view the lucency appears to extend to the articular surface of the bone.

• RD– Subchondral bone cyst of the distal proximal phalanx

• Next– Surgical curretage, however with a cyst in this location, secondary osteoarthritis

will likely occur and the prognosis for soundness is fairly poor.

6 yr old Hanoverian Stallion“Twol”

• HX = acute RF lameness isolated to the foot

6 yr old Hanoverian Stallion“Twol”

6 yr old Hanoverian Stallion“Twol”

• RF– A large, wide radiolucent line is present in the medial quarter/heel of P3 on the DP view.

– Lucent curvilinear shadow seen on the lateral view from the edge of P3 coursing to near the navicular bone.

– The DMPLO view nicely shows the linear lucency, extending from the solar margin to the very edge of the joint.

– A large, ovoid osseous bony structure is present associated with the extensor process of P3 on the lateral view.

– Mild periarticular osteophyte formation on the dorsoproximal surface of P2 is present.

• RD– Non-articular Type I fracture of the medial wing of right front P3

– Type IV P3 fracture, an extensor process fracture

– Mild degenerative joint disease of the P1-2 joint

3 yr old STDB Colt

• HX = acutely non-weight bearing lame in left hindlimb at the end of a race, a cast was applied to the limb prior to transporting the horse

3 yr old STDB Colt• RF

– Fracture lines are seen extending from the sagittal groove of the proximal phalanx and coursing in a disto-lateral direction.

– The fracture exits at the plantaro-lateral aspect of the articular surface of the bone.

– The fracture is minimally displaced.– In the DP view 2 fracture lines are visible in the proximal portion of P1, this is

actually a single fracture line with 2 surfaces (dorsal and plantar), because the x-ray beam is not exactly aligned with the fracture, both surfaces are visible.

– Cast materials surrounds the limb making evaluation of the soft tissues difficult.• RD

– Non-displaced sagittal fracture of the proximal phalanx extending from the articular surface of the metatarsophalangeal joint to the articular surface of the proximal interphalangeal joint

9 yr old Canadian Hunter Mare“Jessica”

• HX = foot abscess

9 yr old Canadian Hunter Mare“Jessica”

• RF

– There is a discrete well-circumscribed lucent defect in the lateral margin of the third phalanx.

– The bone adjacent to the defect is slightly irregular in appearance.

– The areas of increased opacity associated with the soft tissues of the hoof are debris on the solar surface.

• RD

– Osteomyelitis of the third phalanx

6 mo old Belgian Filly“Imperial Julie”

• HX = swollen left hind fetlock

6 mo old Belgian Filly“Imperial Julie”

6 mo old Belgian Filly“Imperial Julie”

• RF– Several various sized osteochondral fragments associated with the proximal mid-

sagittal ridge of distal MT3.– The sagittal ridge is irregular here, indicating a bed from which the fragments

arose.– Soft tissue swelling of the fetlock joint is noted.

• RD– OCD of the sagittal ridge of left metatarsal 3

• Next– Radiographic examination of the remaining fetlocks, as well as the tarsi.

5 yr old STDB Gelding“Blu Meadow Chance”

• HX = acute RF lameness isolated to the foot, two views were taken at the time of injury, plus a DP view 6 months later

5 yr old STDB Gelding“Blu Meadow Chance”

5 yr old STDB Gelding“Blu Meadow Chance”

• RF– The first films show the presence of a linear lucency traversing from the solar

margin of P3 laterally toward the corner of the distal interphalangeal joint.– The recheck film shows this lucent line is still quite evident.

• RD– Type II RF P3 fracture– The follow up films show a fracture line, however P3 fractures often heal by

fibrous, not osseous union, so it may be as healed as it will ever be and if the horse is sound nothing further needs to be done

10 yr old Morgan Mare“Emma”

• HX = The horse fell in a ditch on a trail ride, after the accident she was non-weight-bearing lame on the right hind for 3 days. The lameness improved to a grade 4 of 5 but has gotten no better.

10 yr old Morgan Mare“Emma”

• RF

– There is a fracture extending from the dorsomedial margin to the extensor process of the third phalanx.

– In the lateral view there is osteophyte formation on the extensor process of the third phalanx.

– Irregular periosteal response is present on the dorsal margin of the second phalanx.

• RD

– Fracture of the third phalanx (Type III)

– Degenerative joint disease of the distal interphalangeal joint