Not Just Trauma: Why Bone Sequestra in Camelids Behave Differently

JAVMA 2013

Author

Obi Veterinary Education
January 22, 2026

Marjolaine Rousseau, DMV, MS; David E. Anderson, DVM, MS, DACVS; Andrew J. Niehaus, DVM, MS, DACVS;
Matt D. Miesner, DVM, MS, DACVIM; Sylvain Nichols, DMV, MS, DACVS

Background

Osseous sequestration is increasingly recognized in alpacas and llamas, yet available literature prior to this study was limited to case reports and conference abstracts. Unlike other livestock species, sequestra in camelids appear to occur predominantly in animals under 2 years of age and often in the absence of trauma. The condition has been proposed to arise from hematogenous osteomyelitis rather than direct injury. This study aimed to comprehensively describe clinical presentation, diagnostic findings, treatment approaches, complications, and long-term outcomes in a large cohort of camelids with osseous sequestration.

Methods

A retrospective case series was conducted using medical records from two veterinary teaching hospitals. Alpacas and llamas treated for osseous sequestration between January 1999 and December 2010 were included, excluding cases where sequestra arose from contiguous spread of infection (eg, tooth root abscesses or otitis). Data collected included signalment, history, physical examination findings, imaging results, treatments, surgical details, bacterial culture results, complications, and follow-up outcomes. Descriptive statistics were used, and age differences between trauma- and non–trauma-associated cases were analyzed statistically.

Results

Thirty-six camelids (27 alpacas and 9 llamas) were identified, with a predominance of young, sexually intact males. Median age was under 1 year for most animals, particularly those without a history of trauma. Only 7 of 36 cases were associated with reported trauma; non–trauma-associated cases occurred in significantly younger animals. Common clinical signs included lameness, firm swelling over affected bones, and draining sinuses, although only one-third of camelids had external drainage. Radiography established the diagnosis in most cases, with CT aiding diagnosis in select axial or irregular bone lesions. Long bones were most frequently affected, but axial skeleton involvement was also observed. Thirty-four camelids underwent sequestrectomy, all surviving to discharge. Long-term follow-up (≥ 12 months) was available for 24 camelids, of which 83% recovered without long-term complications.

Limitations

The retrospective design limited standardization of diagnostic testing, imaging protocols, antimicrobial regimens, and follow-up. Long-term outcome data were unavailable for one-third of cases. Not all camelids underwent comprehensive clinicopathologic testing or advanced imaging, and bacterial cultures were not obtained in every case, limiting definitive conclusions regarding etiology.

Conclusions

Osseous sequestration in alpacas and llamas most commonly affects young animals and is frequently unrelated to trauma, distinguishing it from the condition in other livestock species. Hematogenous osteomyelitis is the most likely underlying mechanism in nontraumatic cases. Radiography is typically sufficient for diagnosis, with CT providing added value in complex cases. Sequestrectomy is an effective treatment with a favorable long-term prognosis. Clinicians should consider osseous sequestration in juvenile camelids presenting with lameness, draining tracts, or localized bony swelling.

Radiographic images of the left forelimb of a 3-month-old male alpaca with osseous sequestration. A—Dorsopalmar view obtained by the referring veterinarian 7 days after the cria began to have signs of lameness in the affected limb. Notice the soft tissue swelling surrounding the proximal aspect of the left fused metacarpal bones without evidence of bony lesions. B—Dorsopalmar view of the same left forelimb (LF) 13 days later, revealing a cortical sequestrum of the dorsomedial aspect of the fused metacarpal bones. C—Lateromedial view obtained at the same time as the view in panel B. Physical examination of the cria failed to reveal signs of trauma.

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