Case reveal

Nuclear scintigraphy:

  • Multifocal, moderate to marked increased radiopharmaceutical uptake of the left pelvis (mostly centered on the ilium), most pronounced at the level of the left tuber coxa. No overt pelvic asymmetry is noted.
Note the increased radiopharmaceutical uptake (IRU) in the left hemipelvis when compared to the contralateral side.
  • Moderate radiopharmaceutical uptake of the left greater and suspect third trochanter (limited evaluation).

Summary:

  • Given the findings, consider fractures +/- bone contusion to the left pelvis and left greater and possibly third trochanter secondary to unwitnessed trauma.

Pelvic radiographs:

  • Within the body of the left ischium, a well-defined, sharply margined, complete and short oblique fracture is identified (arrows). The fracture is mildly ventrally displaced with a small fracture gap and extends to the caudal aspect of the left acetabulum without clear articular communication.

Conclusions:

  • The radiographs confirms the presence of a minimally displaced left ischial fracture. An articular component cannot be ruled out. Transrectal ultrasound may be considered to further assess the fracture extent.

A little bit more…

  • Nuclear scintigraphy remains a highly valuable imaging modality to screen the evaluation of fractures of the humerus, tibia and pelvis in horses. It’s the only imaging modality currently allowing full body imaging in horses (Spriet et al.). Abnormal regions of increased radiopharmaceutical uptake in the pelvis are nonspecific but may raise concerns for the presence of fractures.
  • To confirm a diagnosis of pelvic fracture(s), radiography is a reliable and readily available diagnostic tool. Acquisition of ventrodorsal and lateral projections with horses under general anesthesia or standing may be considered; however, to eliminate some associated risks, lateral oblique projections in the standing horse has also been described for evaluation of the caudal iliac body, coxofemoral joint and proximal femur (Barrett et al).
Barrett et al.
  • In non-racehorses, the tuber coxa is the most commonly fractured region of the pelvis due to its more superficial position.
  • In horses under more intense training, such as racehorses, stress fractures of the pelvis may occur due to repetitive concussive trauma (Moiroud et al.).
  • Horses will more commonly be moderately to severely lame at a walk. Asymmetry of the pelvis due to fracture displacement and/or regional soft tissue swelling may be observed in some cases.
  • A rectal exam may be considered to palpate for the presence of fractures. Transrectal ultrasonography is also valuable for the identification of pelvic fractures and associated soft tissue changes (Moiroud et al.).
  • In the majority of cases, treatment of pelvic fractures in horses involves conservative management, mostly involving stall rest and pain management. In some instances, horses may need to be tied to prevent them to lay down and cause fracture displacement/worsening. Surgery is rarely performed in mature horses given the complexity and risks of prolonged anesthesia.
  • Severity of lameness, soft tissue swelling, crepitis, muscle atrophy, and skeletal asymmetry have been reported to have no significant relationship with long-term outcome (Rutkowski et al.). However, other studies reports a poorer prognosis in horses with comminuted fractures.
  • The location/pattern of the fracture sites or articular involvement was not found to have any significant correlation with prognosis per Rutkowski et al., while other studies reports have observed a more guarded prognosis if acetabulum involvement was present (Moiroud et al.).

References:

  • Spriet M, Vandenberghe F. Equine nuclear medicine in 2024: use and value of scintigraphy and PET in equine lameness diagnosis. Animals. 2024 Aug 28;14(17):2499.
  • Little C, Hilbert B. Pelvic fractures in horses: 19 cases (1974-1984). Journal of the American Veterinary Medical Association. 1987 May 1;190(9):1203-6.
  • Rutkowski JA, Richardson DW. A retropspective study of 100 pelvic fractures in horses. Equine veterinary journal. 1989 Jul;21(4):256-9.
  • Moiroud CH, Coudry V, Denoix JM. Outcome of pelvic fractures identified in 75 horses in a referral centre: a retrospective study. Veterinary and Comparative Orthopaedics and Traumatology. 2019 Jul;32(04):274-81.
  • Ducharme NG, Nixon AJ. Fractures of the pelvis. Equine fracture repair. 2019 Oct 28:723-33.
  • Barrett EL, Talbot AM, Driver AJ, Barr FJ, Barr AR. A technique for pelvic radiography in the standing horse. Equine veterinary journal. 2006 May;38(3):266-70.
  • Moiroud CH, Coudry V, Denoix JM. Distribution of pelvic fractures in racing and non-racing sport horses: a retrospective study of 86 cases examined in a referral centre. Veterinary and Comparative Orthopaedics and Traumatology. 2019 May;32(03):215-21.