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Equine veterinary journal2025; doi: 10.1111/evj.14495

Computed tomography of the equine temporohyoid joint: Association between imaging changes and potential risk factors.

Abstract: Temporohyoid osteoarthropathy (THO) is characterised by bone proliferation and cartilage ossification caused by infectious and degenerative conditions, amongst others. Objective: To describe the variable appearance of the temporohyoid joint (THJ) on computed tomography (CT) and investigate associations between CT changes and potential risk factors. Methods: Cross-sectional study. Methods: Head CT examinations were assessed. A grading system was developed for osseous proliferation (grade 0 [normal] to 3 [severe]) and tympanohyoid cartilage change (grade 0 [normal] to 3 [complete ossification]). Grades were also summed to create an overall sum grade. Ordinal logistic regression was performed to produce a multivariable model that assessed the association between THJ grade and signalment, presenting signs, CT features, and final diagnosis. Results: The horses included (n = 424) most commonly presented for dental and sinus disorders (37.7%). The most frequently observed (mode) bone grade, cartilage grade and overall grade were 2 (41.9%), 0 (52.6%) and 2 (27.0%), respectively. Bone proliferation was most common medially and caudally. Soft tissue swelling (OR 1.9, 95% CI 1.2-3.1, p < 0.05) and temporal bone fragmentation (OR 26.6, 95% CI 5.1-141.4, p < 0.05) were associated with increased bone grade. There was no correlation between increased grade and any presenting sign. Increased sum grade was significantly associated with increased age (OR per year 1.1, 95% CI 1.0-1.1, p < 0.05), Arabians (OR 4.2, 95% CI 1.3-14.0, p < 0.05) and Thoroughbreds (OR 2.9, 95% CI 1.5-5.4, p < 0.05) relative to Warmbloods. Conclusions: Following training, a single observer evaluated images. Conclusions: Moderate caudomedial osseous proliferation of the THJ is common in horses presented for unrelated disease. Cartilage mineralisation, soft tissue swelling, and temporal bone fragmentation may serve as markers of disease. Thoroughbreds and Arabians are at increased risk of greater THJ remodelling. Increased THJ change was associated with age but not otitis, suggesting THO is predominantly degenerative. Unassigned: Die Temporohyoid‐Osteoarthropatie (THO) ist durch Knochenproliferation und Verknöcherung des Knorpels gekennzeichnet, welche unter anderem durch infektiöse und degenerative Erkrankungen verursacht werden. Unassigned: Beschreibung des variablen Erscheinungsbildes des Temporohyoidgelenks (THJ) in der Computertomographie (CT) und Untersuchung von Zusammenhängen zwischen CT‐Veränderungen und möglichen Risikofaktoren. Methods: Querschnittsstudie. Methods: CT‐Untersuchungen des Kopfes wurden ausgewertet. Es wurde ein Bewertungssystem für die knöcherne Proliferation (Grad 0 [normal] bis 3 [schwerwiegend]) und die tympanohyoidale Knorpelveränderung (Grad 0 [normal] bis 3 [vollständige Verknöcherung]) entwickelt. Die Grade wurden auβerdem addiert, um einen Gesamtsummengrad zu erhalten. Es wurde eine logistische Ordinalregression durchgeführt, um ein multivariables Modell zu erstellen, das den Zusammenhang zwischen Grad des THJ und des Signalements, Vorstellungsgrund, CT‐Merkmalen und der endgültigen Diagnose beurteilte. Unassigned: Die einbezogenen Pferde (n = 424) wurden am häufigsten wegen Zahn‐ und Kieferhöhlenerkankungen vorgestellt (37,7%). Der am häufigsten beobachtete Knochengrad, Knorpelgrad und Gesamtsummengrad waren 2 (41,9%), 0 (52,6%) und 2 (27,0%). Knochenproliferationen traten am häufigsten medial und kaudal auf. Weichteilschwellungen (OR 1,9, 95% CI 1,2‐3,1, p < 0,05) und Knochenfragmentierung des Os Temporale (OR 26,6, 95% CI 5,1‐141,4, p < 0,05) waren mit einem erhöhten Knochengrad verbunden. Es gab keine Korrelation zwischen erhöhtem Grad und einem der Vorstellungsgründe. Ein erhöhter Summengrad war signifikant mit einem höherem Alter (OR pro Jahr 1,1, 95% CI 1,0‐1,1, p < 0,05), Arabern (OR 4,2, 95% CI 1,3‐14,0, p < 0,05) und Vollblütern (OR 2,9, 95% CI 1,5‐5,4, p < 0,05) im Vergleich zu Warmblütern verbunden. HAUPTEINSCHRÄNKUNGEN: Nach dem Training wurde ein einzelner Beobachter eingesetzt. Unassigned: Eine mäβige kaudomediale knöcherne Proliferation des THJ ist bei Pferden, die wegen einer nicht im Zusammenhang stehenden Krankheit vorstellig werden, häufig. Knorpelmineralisierung, Weichteilschwellung und Fragmentierung des Os Temporale können als Marker für Erkrankung dienen. Vollblüter und Araber haben ein erhöhtes Risiko für eine stärkere Umbildung des THJ. Vermehrte Veränderungen des THJ wurden mit dem Alter, nicht aber mit einer Otitis in Verbindung gebracht, was darauf hindeutet, dass die THO überwiegend degenerativ ist.
© 2025 The Author(s). Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.
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Publication Date: 2025-05-05 PubMed ID: 40322953DOI: 10.1111/evj.14495Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research looked at the variables and potential risk factors of Temporohyoid osteoarthropathy (THO), a degenerative bone disease found in horses. Study was based on horse CT scans and developed a grading system to evaluate bone proliferation and joint changes. It found factors like breed and age of the horse did influence the severity of the osteoarthropathy, but there was no association between higher grading and the presenting sign of illness.

Study Overview

  • This research used a cross-sectional study model, where a group of 424 horses were sampled once and observed for potential signs and risk factors related to THO, a degenerative joint disease that can affect horses.
  • The researchers used computed tomography (CT) scans of the horse’s heads and analyzed the temporohyoid joint (THJ), a small but integral joint that connects the skull with the first vertebra and aids the horse in head movement and stability.
  • A grading system was developed for evaluating osseous (bony) proliferation and changes in tympanohyoid cartilage, ranging from normal (0) to severe (3). These grades were then summed to create an overall score for THJ changes in each horse.

Findings

  • Most horses in the study were seen for dental or sinus disorders. The most frequently observed bone grade was 2 (41.9%), indicating moderate bone changes, while the cartilage grade was most often 0 (52.6%) implying normal cartilage. The combined sum grade was most typically also 2 (27.0%).
  • Bone modifications were most often seen on the medial (towards the middle) and caudal (towards the back) aspects of the joint.
  • Increased bone grade was significantly associated with soft tissue swelling and temporal bone fragmentation. But there was no link found between an elevated grade and any presenting sign of disease in the horse at the time of the CT scan.
  • Increased overall grade was significantly associated with an increase in the age of the horse, with each additional year of age increasing the chances of a higher THJ change.
  • Certain breeds (Arabians and Thoroughbreds) were more prone to THJ remodelling compared to others.

Conclusions

  • The study concluded moderate caudomedial (rear and middle) bone proliferation of the THJ is common in horses presented for unrelated disease.
  • Cartilage mineralisation, soft tissue swelling, and temporal bone fragmentation can serve as potential markers of the disease.
  • The research suggested that THO is predominantly degenerative as its relationship to age was confirmed but there wasn’t any association with any disease signs at the time of the CT scan.

Cite This Article

APA
Dash RF, Perkins JD, Chang YM, Morgan RE. (2025). Computed tomography of the equine temporohyoid joint: Association between imaging changes and potential risk factors. Equine Vet J. https://doi.org/10.1111/evj.14495

Publication

Equine veterinary journal
ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English

Researcher Affiliations

Dash, Rupert F
  • The Royal Veterinary College, Equine Referral Hospital, North Mymms, Hertfordshire, UK.
Perkins, Justin D
  • The Royal Veterinary College, Equine Referral Hospital, North Mymms, Hertfordshire, UK.
Chang, Yu-Mei
  • The Royal Veterinary College, Equine Referral Hospital, North Mymms, Hertfordshire, UK.
Morgan, Rhiannon E
  • IVC Evidensia UK, The Chocolate Factory, Bristol, UK.

References

This article includes 19 references
  1. Sisson S, Grossman JD, Getty R. The anatomy of the domestic animals. Vol 1. 5th ed. Philadelphia: W B Saunders Company; 1975.
  2. Naylor RJ, Perkins JD, Allen S, Aldred J, Draper E, Patterson‐Kane J. Histopathology and computed tomography of age‐associated degeneration of the equine temporohyoid joint. Equine Vet J 2010;42(5):425–430.
  3. Moore KL, Dailey AF, Agur AMR. Moore's: clinically oriented anatomy. 7th ed. Alphen aan den Rijn: Wolters Kluwer; 2013.
  4. Divers TJ, Ducharme NG, de Lahunta A, Irby NL, Scrivani PV. Temporohyoid osteoarthropathy. Clin Tech Equine Pract 2006;5(1):17–23.
  5. Walker AM, Sellon DC, Comelisse CJ, Hines MT, Ragle CA, Cohen N. Temporohyoid osteoarthropathy in 33 horses (1993–2000). J Vet Intern Med 2002;16(6):697–703.
  6. Koch C, Witte T. Temporohyoid osteoarthropathy in the horse. Equine Vet Educ 2014;26(3):121–125.
  7. Whitty JA, Miller AV, Miller AD, Carney PC, Scrivani PV. Associations between styloid process sheath CT sizes and age, body weight, and breed in horses. Vet Radiol Ultrasound 2022;63(4):436–449.
  8. Tanner J, Spriet M, Espinosa‐Mur P, Estell KE, Aleman M. The prevalence of temporal bone fractures is high in horses with severe temporohyoid osteoarthropathy. Vet Radiol Ultrasound 2019;60(2):159–166.
  9. Inui T, Yamada K, Itoh M, Yanagawa M, Higuchi T, Watanabe A. Computed tomography and magnetic resonance imaging findings for the initial stage of equine temporohyoid osteoarthropathy in a Thoroughbred foal. J Equine Sci 2017;28(3):117–121.
  10. Blythe LL. Otitis media and interna and temporohyoid osteoarthropathy. Vet Clin North Am Equine Pract 1997;13(1):21–42.
  11. Blythe LL, Watrous BJ, Pearson EG, Walker LL. Otitis media interna in the horse: a cause of headshaking and skull fractures. Proc Am Assoc Equine Pract 1990;517–528.
  12. Palus V, Bladon B, Brazil T, Cherubini GB, Powell SE, Greet TRC. Retrospective study of neurological signs and management of seven English horses with temporohyoid osteoarthropathy. Equine Vet Educ 2012;24(8):415–422.
  13. Belmudes A, Pressanti C, Barthez PY, Castilla‐Castaño E, Fabries L, Cadiergues MC. Computed tomographic findings in 205 dogs with clinical signs compatible with middle ear disease: a retrospective study. Vet Dermatol 2018;29(1):45.
  14. Pownder S, Scrivani PV, Bezuidenhout A, Divers TJ, Ducharme NG. Computed tomography of temporal bone fractures and temporal region anatomy in horses. J Vet Intern Med 2010;24(2):398–406.
  15. Saito Y, Amaya T. Symptoms and management of temporohyoid osteoarthropathy and its association with crib‐biting behavior in 11 Japanese Thoroughbreds. J Equine Sci 2019;30(4):81–85.
  16. Aleman M, Spriet M, Williams DC, Nieto JE. Neurologic deficits including auditory loss and recovery of function in horses with temporohyoid osteoarthropathy. J Vet Intern Med 2016;30(1):282–288.
  17. Johns IC, Finding EJT, Ciasca T, Erles K, Smith K, Weller R. Intracranial botryomycosis in a mature horse. Equine Vet Educ 2014;26(6):294–298.
  18. Omori K, Ishikawa K, Obinata M, Mishima K, Fukusato S, Ohsaka H. Significance of the vacuum phenomenon in patients with trauma evaluated by whole‐body computed tomography. Am J Emerg Med 2015;33(2):282–285.
  19. Gohil I, Vilensky JA, Weber EC. Vacuum phenomenon: Clinical relevance. Clin Anat 2014;27(3):455–462.

Citations

This article has been cited 1 times.
  1. Hartl B, Strohmayer C, Vali Y, Lyrakis M, Kneissl SM. Computed tomographic signs of hyoid apparatus disease in 165 horses. Front Vet Sci 2025;12:1631185.
    doi: 10.3389/fvets.2025.1631185pubmed: 41049149google scholar: lookup
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