History
A 5-month-old 145-kg (319-lb) Holstein heifer calf was referred to the Iowa State University Food Animal and Camelid Hospital because of a 14-day history of lameness and tibiotarsal joint swelling in the right hind limb. The calf had no history of trauma or infection and had been treated on the farm with meloxicam (1 mg/kg [0.45 mg/lb], PO, q 24 h for 3 days) with no resolution of clinical signs. On physical examination, the calf was weight-bearing on the right hind limb but had a short stride with an arched back during movement (lameness grade,1 2/5). Also, in the right hind limb, the tarsus (hock) was diffusely warm to the touch and the tibiotarsal joint had marked effusion. Results of flexion tests on the right hind limb identified no further abnormalities, and the remaining findings from physical examination were within reference limits. Radiography of the right hock was performed (Figure 1).
Dorsoplantar (A), lateromedial (B), dorsolateral-plantaromedial oblique (C), and dorsomedial-plantarolateral oblique (D) radiographic images of the right tarsus (hock) of a 5-month-old 145-kg (319-lb) Holstein heifer calf with a grade 2/5 lameness in the right hind limb.
Citation: Journal of the American Veterinary Medical Association 259, 4; 10.2460/javma.259.4.357
Dorsoplantar (A), lateromedial (B), dorsolateral-plantaromedial oblique (C), and dorsomedial-plantarolateral oblique (D) radiographic images of the right tarsus (hock) of a 5-month-old 145-kg (319-lb) Holstein heifer calf with a grade 2/5 lameness in the right hind limb.
Citation: Journal of the American Veterinary Medical Association 259, 4; 10.2460/javma.259.4.357
Dorsoplantar (A), lateromedial (B), dorsolateral-plantaromedial oblique (C), and dorsomedial-plantarolateral oblique (D) radiographic images of the right tarsus (hock) of a 5-month-old 145-kg (319-lb) Holstein heifer calf with a grade 2/5 lameness in the right hind limb.
Citation: Journal of the American Veterinary Medical Association 259, 4; 10.2460/javma.259.4.357
Diagnostic Imaging Findings and Interpretation
A well-demarcated, round, focal area of increased lucency was identified near the distomedial aspect of the talus, calcaneus, or both (Figure 2). Whether the radiolucent lesion communicated with an articular surface was unclear. Additionally, there was moderate soft tissue swelling but no evidence of fracture or osseous proliferation. The primary differential diagnosis for this lesion and location was a subchondral bone cyst or focal osteolysis secondary to synovial infection.
Same images as Figure 1. A well-demarcated, round, focal area of increased lucency (arrows) is near the distomedial aspect of the talus, calcaneus, or both. Moderate soft tissue swelling is evident. There is no evidence of fracture or osseous proliferation.
Citation: Journal of the American Veterinary Medical Association 259, 4; 10.2460/javma.259.4.357
Same images as Figure 1. A well-demarcated, round, focal area of increased lucency (arrows) is near the distomedial aspect of the talus, calcaneus, or both. Moderate soft tissue swelling is evident. There is no evidence of fracture or osseous proliferation.
Citation: Journal of the American Veterinary Medical Association 259, 4; 10.2460/javma.259.4.357
Same images as Figure 1. A well-demarcated, round, focal area of increased lucency (arrows) is near the distomedial aspect of the talus, calcaneus, or both. Moderate soft tissue swelling is evident. There is no evidence of fracture or osseous proliferation.
Citation: Journal of the American Veterinary Medical Association 259, 4; 10.2460/javma.259.4.357
Arthrocentesis of the tibiotarsal joint was performed, and synovial fluid analysis revealed that the total nucleated cell count was 14,200 cells/µL (reference range, < 1,000 cells/µL) and total protein concentration was 4.4 g/dL (reference range, < 2.5 g/ dL).2 Cytologic examination of the synovial fluid revealed 89% neutrophils (reference range, 10% to 20%), 8% lymphocytes (reference range, 0% to 2%), and 3% mononuclear cells (reference range, 0% to 2%).2 Neutrophils were predominately nondegenerate. Synovial samples were obtained for aerobic and anaerobic bacterial cultures and mycoplasma PCR assay, and CT was recommended to better determine the anatomic location of the lesion and whether there was articular involvement.
The calf was sedated with xylazine (0.02 mg/ kg [0.009 mg/lb], IV), and a 16-slice multidetector system was used for CT of both hocks (for comparative anatomic structure) with transverse 0.7-mm slice thickness in algorithms for bone (window level, 500 HU; window width, 2,000 HU) and soft tissue (window level, 50 HU; window width, 350 HU) from the middle of the tibial diaphysis to the middle of the diaphysis of the fused third and fourth metatarsal bones on each limb. Images were reformatted in dorsoplantar and sagittal planes and revealed a hypoattenuating, focal defect (approx 9 X 7 X 6 mm) at the articular surface of the right calcaneus (Figure 3). This subchondral lesion was surrounded by sclerosis and appeared to communicate with the proximal inter-tarsal joint. In a further attempt to identify whether the lesion communicated with the joint cavity, CT arthrography (not shown) was performed after injecting 35 mL of a diluted solution of contrast medium (iohexol [350 mg I/mL] diluted 50% with saline [0.9% NaCl] solution) into the tibiotarsal joint with a dorsomedial approach. Contrast enhancement of the tibiotarsal joint was achieved; however, diffusion into the proximal intertarsal joint did not occur.
Dorsoplantar (A), sagittal (B), and transverse (C) plane CT images of the right hock of the calf described in Figure 1. A hypoattenuating, focal bone defect (arrows) with surrounding sclerosis, consistent with a bone cyst, is at the distal articular surface of the right calcaneus and appears to communicate with the proximal intertarsal joint.
Citation: Journal of the American Veterinary Medical Association 259, 4; 10.2460/javma.259.4.357
Dorsoplantar (A), sagittal (B), and transverse (C) plane CT images of the right hock of the calf described in Figure 1. A hypoattenuating, focal bone defect (arrows) with surrounding sclerosis, consistent with a bone cyst, is at the distal articular surface of the right calcaneus and appears to communicate with the proximal intertarsal joint.
Citation: Journal of the American Veterinary Medical Association 259, 4; 10.2460/javma.259.4.357
Dorsoplantar (A), sagittal (B), and transverse (C) plane CT images of the right hock of the calf described in Figure 1. A hypoattenuating, focal bone defect (arrows) with surrounding sclerosis, consistent with a bone cyst, is at the distal articular surface of the right calcaneus and appears to communicate with the proximal intertarsal joint.
Citation: Journal of the American Veterinary Medical Association 259, 4; 10.2460/javma.259.4.357
Treatment and Outcome
Aerobic and anaerobic bacterial cultures yielded no growth, and results were negative for mycoplasma PCR assay. On the basis of these findings, aseptic synovitis was determined most likely. Meloxicam (1 mg/kg, PO, q 24 h) was continued, and joint lavage with sterile saline solution was performed. The calf's lameness improved to grade 1 within 36 hours after the procedure. Possible treatment protocols to support the affected joint included continued conservative management, steroid injection into the lesion, placement of a lag screw into the cyst, or treatment with autologous conditioned serum (ACS), also known as interleukin-1 receptor antagonist protein [IL-1ra or IRAP]) serum. Surgery as a first-line treatment was not elected. Steroid injection into the cyst was rejected because of the possibility of potentiating any underlying infection. Intra-articular injection of ACS as a means to reduce intra-articular inflammation was elected.
Thus, the calf was sedated with xylazine (0.02 mg/kg, IV) for radiographic guidance of an injection of 4 mL of ACS into the right proximal intertarsal joint. The right tibiotarsal joint was also injected with 4 mL of ACS but without radiographic guidance. After treatment, the calf continued to improve and was considered sound for breeding use 12 months later.
Comments
Our presumptive diagnosis for the subchondral bone cyst of the calcaneus in the calf of the present report was a congenital bone cyst, as opposed to a lesion caused by an underlying infection. It is unknown whether congenital bone cysts are common in immature cattle, and the cause, including whether there is a genetic inheritance pattern, is unknown. Long-term effects of subsequent lameness on performance (eg, milk production or rate of gain) are also unknown; however, extrapolation from other orthopedic disorders suggests that a subchondral bone cyst would produce chronic pain, which could negatively affect the production and thus the value of the animal.
Delineating an accurate location and dimensions of a bone cyst and demonstrating whether there is articular communication are difficult with radiography alone, as was the case in the calf of the present report. Therefore, we used CT to accurately identify the affected structures and the anatomic features of the bone cyst. This allowed us to better assess the lesion and treatment options. Further evaluation with CT arthrography was attempted; however, the inability to deliver sufficient volume of contrast medium into the proximal intertarsal joint limited additional the procedure's diagnostic benefits.
Intra-articular administration of ACS is widely used in the treatment of joint inflammation in humans and horses3 but, to our knowledge, has not been reported previously in cattle. The mechanism of ACS is thought to be from the high concentration of the anti-inflammatory cytokine IL-1ra limiting the cellular effects of pro-inflammatory cytokines, such as interleukin-1β.3
Bone cysts should be considered as a differential diagnosis for lameness in cattle. In the calf of the present report, diagnostic imaging included radiography and CT, both of which identified a cystic bone lesion; however, with CT, we clearly identified that the bone cyst was in the calcaneus. Compared with radiography, CT better delineated the bone cyst location and size and further contributed to a more accurate prognosis and optimal treatment plan for the calf of the present report.
References
- 1. ↑
Sprecher DJ, Hostetler DE, Kaneene JB. A lameness scoring system that uses posture and gait to predict dairy cattle reproductive performance. Theriogenology 1997;47:1179– 1187.
- 2. ↑
Cornell University College of Veterinary Medicine. eClinpath synovial fluid page. Available at: eclinpath.com/cytology/synovial-fluid/. Accessed Mar 15, 2019.
- 3. ↑
Hraha TH, Doremus KM, McIlwraith CW, et al. Autologous conditioned serum: the comparative cytokine profiles of two commercial methods (IRAP and IRAP II) using equine blood. Equine Vet J 2011;43:516–521.
