History
A 14-month-old 63-kg neutered male Saint Bernard was presented for investigation of a chronic and gradually left thoracic limb lameness of several months’ duration. Oral administration of meloxicam (Metacam; Boehringer Ingelheim), 0.2 mg/kg every 24 hours for 7 days, and osteopathic treatment failed to improve the lameness.
The dog has been referred for further examinations and a surgeon’s second opinion. At the presentation, the dog had a severe weight-bearing lameness (grade 3 using a 0 to 5 scale).1 Moderate pain was elicited on the shoulder’s hyperflexion test and elbow Campbell test (the elbow is held in flexed position and the carpus is rotated externally to lead to a compression of the medial compartment of the elbow by the medial collateral ligament. In the case of medial compartment disease, the test is often accompanied by pain). Moreover, cracking of the joint was audible during manipulation of the elbow; the rest of the orthopedic examination and clinical review findings were otherwise unremarkable. Computed tomography (Figure 1) and arthroscopic evaluation (Figure 2) were performed on the left elbow.
Computed tomography multiplanar reformation images of the left elbow in transverse, sagittal, and frontal planes of a 14-month-old 63-kg neutered male Saint Bernard presented for evaluation of chronic left forelimb lameness. Window settings: 500-2500 HU window (window width: 2000 HU; window level: 1500 HU), and 1.2-mm slice thickness.
Citation: Journal of the American Veterinary Medical Association 262, 9; 10.2460/javma.24.04.0246
Arthroscopic evaluation of the left elbow of the same dog as presented in Figure 1, at the level of the ulnar trochlear notch (A) and inside the humeroulnar space (B).
Citation: Journal of the American Veterinary Medical Association 262, 9; 10.2460/javma.24.04.0246
Diagnostic Imaging Findings and Interpretation
On CT images, a slight sclerosis of the subchondral bone was noted next to the ulnar notch. A lack of articular congruence was present at this level, objectified by the presence of a gap between the humerus and the trochlear notch (Figure 3). A large ulnar notch defect was confirmed by arthroscopy. A remarkable 1-cm-length joint mice was associated with this defect that looked like osteochondritis lesion (Figure 4).
Same CT multiplanar reformation images as in Figure 1. Subchondral bone sclerosis is present at the level of the trochlear notch of the ulna (red arrows). The trochlear notch surface is irregular with a focal increased space between the humerus and ulna and incongruency at this level (yellow arrows).
Citation: Journal of the American Veterinary Medical Association 262, 9; 10.2460/javma.24.04.0246
Same arthroscopic images as in Figure 2. A well-delimited defect of cartilage and subchondral bone was present on the trochlear notch of the ulna (red arrow). Peripheric cartilage of the lesion was remodeled (black arrows). A free joint mouse of approximately 1 cm was present in the joint, corresponding to the ulnar bone and cartilage defect (blue arrow).
Citation: Journal of the American Veterinary Medical Association 262, 9; 10.2460/javma.24.04.0246
Other lesions were seen on both CT and arthroscopic evaluation. The left medial coronoid process of the ulna was highly remodeled. A hypoattenuating line was noted next to its extremity, delimiting an oval fragment of 11-mm by 6 mm, with very little displaced cranially. Smooth and regular bone productions were noted at the articular margins. Moreover, signs of chronic panosteitis were present on CT evaluation (endosteal bone productions into medullar cavities of humerus, ulnas, and radius, centered on the nutrient foramen.)
Treatment and Outcome
Arthroscopic evaluation of the elbow was associated with a focal treatment of lesions of the medial coronoid process and ulnar trochlear notch. Fragments of medial coronoid process were removed with an arthroscopic-hand alligator forceps and asubtotal coronoid process ostectomy was performed to complete treatment. Joint mice was removed and abrasion of the bed of the lesion on the ulna was performed with a motorized 3-mm burr to promote bone healing.
Recovery was uneventful. The patient was discharged with anti-inflammatory, painkiller, antibiotics and strict rest. Twelve days after surgery, for the suture removal, lameness still existed but support on the limb was sufficient. Two months postoperatively, lameness remained but was slightly better, and manipulation as walking was painless. An owner interview performed 1 year later revealed chronic lameness with a global improvement following surgery. The owner declined further clinical or imaging follow-up.
Comments
The authors reported here an unusual localization of an osteochondrosis lesion in the trochlear notch of the ulna of a dog. In this case, several lesions were diagnosed on the same limb: panosteitis of the ulna and humerus, medial coronoid process fragmentation, and osteochondrosis dissecans of the ulnar trochlear notch. This association of several lesions prevented the authors from concluding about the predominancy of the osteochondrosis lesion or another one in the lameness and pain of the dog. This case report is mainly worth the value of describing a new localization of osteochondrosis and make veterinarians aware of its existence for future elbow evaluations.
Widely reported and accepted sites of synovial osteochondrosis in dogs are the humeral head, medial aspect of the humeral condyle, lateral or medial femoral condyle, and medial or lateral trochlear ridge of the talus.1 Localization of an osteochondrosis lesion in the trochlear notch of the ulna has not ever been described in the veterinary literature at the time of writing.
Radiography is the most common way to investigate osteoarticular lesions, particularly osteochondrosis.2 It typically demonstrates disruption of the subchondral bone, flattening or concavity of its normal contour, and sometimes sclerotic margins of the lesion. A cartilage flap is sometimes seen within the subchondral defect if it is mineralized. If separated from the cartilage surface and mineralized, a joint mice that have migrated within the joint space can be seen. Adjunctive intraarticular contrast injection allows more information concerning articular cartilage including cartilage flap and joint mice. The x-ray must be perpendicular to the lesion to be seen on images.2 The authors do not know if the osteochondritis described herein could be seen on radiographic evaluation because of bone superposition in the elbow that might hide lesions on images. Moreover, fragmentation of the medial coronoid process is often associated with subchondral bone sclerosis of the ulna, and a risk of focusing on the medial coronoid disease and misdiagnosing the ulnar osteochondrosis might happen with radiographic evaluation in this case.
More precise imaging modalities such as CT or RMI may be useful if radiographs have failed to make the diagnosis.3 In the case presented herein, the authors elicited a CT exam in a first attempt as signalment of the dog and clinical exam was consistent with elbow dysplasia. Computed tomography is currently considered the gold standard way to evaluate elbow dysplasia.3 Associated arthroscopy allows complementary evaluation of articular cartilage surface and may allow complementary focal treatment of the disease during the same procedure.4 The joint mice was not seen on CT exam in this case, probably because it was not mineralized. As CT showed an erratic localization of the osteochondrosis lesion, arthroscopy was useful to evaluate more precisely the bed of the lesion on the ulnar trochlear notch, and the joint mice that had followed cartilage flap detachment from the bone. Palpation of the articular cartilage surface with an arthroscopic probe was made to ensure the absence of another cartilage flap detached from the bone. Then, the joint mice was removed, and the bed of the osteochondrosis lesion was treated with a motorized burr to promote bone healing.
A presumptive diagnosis of osteochondrosis was made on imaging modalities (CT and arthroscopy). Histopathologic evaluation of both the joint mice and the bed lesion on the ulnar trochlear notch would have been interesting to confirm this suspicion. The authors did not have a histopathologic analysis of the lesion. It should have been interesting to have information about subchondral bone vasculature, cartilage disruption, and cartilage necrosis to know more about the etiology of the lesion encountered in the dog.
An association of several lesions is frequent in dogs suffering from elbow dysplasia. Computed tomography is particularly interesting to evaluate the joint and a complete diagnosis. The association of osteochondrosis of the humeral condyle and medial coronoid disease is a frequent finding and did not worsen the postoperative prognosis as compared with medial coronoid disease found alone in a retrospective study.5 The authors did not know if this observation could be extrapolated with a localization of the osteochondrosis lesion to the ulnar trochlear notch.
Acknowledgments
The authors would like to thank Mathieu Harel, DVM, DECVDI, for interpretation of CT images.
Disclosures
The authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.
Funding
The authors have nothing to disclose.
ORCID
B. Vedrine https://orcid.org/0000-0003-1118-0919
References
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