Objective—To determine the molecular and histologic characteristics of hyperextension of the metacarpophalangeal and metatarsophalangeal joints in adult llamas.
Animals—12 adult llamas (6 with bilateral hyperextension of the metacarpophalangeal or metatarsophalangeal joints [affected] and 6 age- and sex-matched clinically normal control llamas).
Procedures—Llamas were euthanized, and specimens of superficial digital flexor tendon, deep digital flexor tendon, and suspensory ligament were obtained from 4 areas and snap frozen in liquid nitrogen or suspended in neutral-buffered 10% formalin. Histologic evaluation of collagen fiber orientation, elastin content, and proteoglycan content was performed by use of Masson trichrome, picrosirius red, Verhoeff, and Alcian blue stains. Total RNA was isolated from frozen suspensory ligament specimens. Gene expression of collagen types I and III, lysyl oxidase, and matrix metalloproteinase-13 was evaluated with a real-time quantitative reverse transcriptase PCR assay.
Results—Gene expression of collagen types I and III, lysyl oxidase, and matrix metalloproteinase-13 in suspensory ligaments was similar between affected and control llamas. Collagen orientation and elastin content of the flexor tendons and suspensory ligaments were also similar between the groups. Proteoglycan content was low in most specimens but was focally increased in discrete lesions of suspensory ligaments in 2 affected and 2 control llamas.
Conclusions and Clinical Relevance—Hyperextension of the metacarpophalangeal or metatarsophalangeal joints in llamas did not appear to be caused by degeneration or inflammation of the suspensory ligament. Although focal proteoglycan accumulation existed in the suspensory ligaments of 2 affected llamas, widespread abnormal connective tissue proteoglycan accumulation was not found.
Case Description—A 2-year-old male Suri alpaca was referred for evaluation of severe right forelimb lameness of 2 weeks' duration following a traumatic episode.
Clinical Findings—Examination of the distal aspect of the metacarpus revealed 4 wounds exuding purulent material. On weight bearing, the metacarpophalangeal joint was severely hyperextended with the palmar surface touching the ground. Ultrasonography of the palmar surface of the metacarpus revealed desmitis of the proximal suspensory ligament, a large core lesion of the deep digital flexor tendon at mid-metacarpus, and complete loss of fiber pattern within the deep digital flexor tendon and lateral aspect of the superficial digital flexor tendon distally.
Treatment and Outcome—The alpaca was treated systemically with antimicrobials and anti-inflammatory drugs and underwent repeated antimicrobial intraosseous regional limb perfusion. A bandage and splint were applied to stabilize the affected forelimb in an anatomically correct position, and the alpaca underwent prolonged stall confinement. At the time of hospital discharge 5 days after initial evaluation, clinical evidence of infection at the wound sites was absent. Three months following treatment, the alpaca was moving freely in a small paddock and had moderate hyperextension of the metacarpophalangeal joint.
Clinical Relevance—Treatment of septic flexor tendonitis and suspensory desmitis with antimicrobial intraosseous regional limb perfusion in combination with systemic treatment with antimicrobials and orthopedic support resulted in an excellent outcome in this alpaca. Antimicrobial intraosseous regional limb perfusion is simple to perform and has the potential to be beneficial in the treatment of infections in the distal portion of a limb in camelids.
Objective—To determine the anatomic communications
among compartments within the carpus,
metacarpophalangeal and metatarsophalangeal
joints, stifle joint, and tarsus in llamas.
Sample Population—88 limbs from 22 llamas
necropsied because of reasons unrelated to disease
of the carpus; tarsus; or metacarpophalangeal,
metatarsophalangeal, or stifle joints.
Procedure—1 compartment (randomly assigned) of
each joint was injected with blue latex solution.
Communication between joint compartments was
determined by observation of latex in adjacent compartments
following frozen sectioning.
Results—Of the 44 carpi, 30 (68%) had anatomic
separation between the radiocarpal and middle carpal
joints, whereas the remaining 14 (32%) had communication
between the radiocarpal and middle carpal
joints. In the metacarpophalangeal or metatarsophalangeal
joints, medial and lateral joint compartments
remained separate in 83 of 88 (94%) joints injected.
The tibiotarsal and proximal intertarsal joints communicated
in all tarsi examined, whereas 14 of 38 (37%)
communicated between the proximal intertarsal and
distal intertarsal joints. Communication between the
distal intertarsal and tarsometatarsal joints was
detected in 17 of 25 (68%) specimens; all 4 tarsal
joints communicated in 11 of 42 (26%) specimens
examined. Examination of 33 stifle joints that were
successfully injected revealed communication
between the femoropatellar, medial femorotibial, and
lateral femorotibial joints.
Conclusions and Clinical Relevance—These data
suggest that it is important to determine the joint
communications specific to each llama prior to treatment
of septic arthritis. The metacarpophalangeal or
metatarsophalangeal joint compartments may be
considered separate, although the lateral and medial
compartments infrequently communicate along the
proximal palmar or plantar aspect. (Am J Vet Res 2005;66:1437–1440)
Objective—To evaluate molecular and histologic characteristics of the superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), and suspensory ligament (SL) and assess trace-mineral concentrations in serum, liver, and hair of juvenile llamas with metacarpophalangeal and metatarsophalangeal joint hyperextension.
Animals—12 juvenile llamas (6 with bilateral hyperextension of metacarpophalangeal joints, metatarsophalangeal joints, or both and 6 clinically normal control llamas).
Procedures—Radiography and ultrasonography of metacarpophalangeal and metatarsophalangeal regions were performed. Llamas were euthanized, and SDFT, DDFT, and SL samples were collected for histologic evaluation of collagen and elastin content and orientation, proteoglycan content, and collagen type III immunohistochemistry. Total RNA was isolated from SL tissue, and gene expression of collagen types I and III, lysyl oxidase, and matrix metalloproteinase-13 was evaluated via real-time quantitative reverse transcriptase PCR assay. Liver, serum, and hair samples were evaluated for trace mineral content.
Results—Collagen type III gene expression and proteoglycan content were significantly increased in SL samples of affected juvenile llamas, compared with those of control llamas. No difference was detected in collagen and elastin content and orientation or in gene expression of collagen type I, lysyl oxidase, or matrix metalloproteinase-13 between groups. Affected llamas had significantly increased serum molybdenum and decreased liver cobalt concentrations, compared with values for control llamas.
Conclusions and Clinical Relevance—Increased collagen type III gene expression and proteoglycan content in SL samples of affected juvenile llamas provided evidence of ongoing SL matrix repair. Trace mineral differences may have been attributable to dietary imbalances in affected llamas.
OBJECTIVE To determine and compare mean standing extension and maximum flexion angles of various joints in healthy adult alpacas and llamas, and determine the reliability of goniometric data within and between 2 observers for each joint of interest.
SAMPLE 6 healthy adult llamas and 6 healthy adult alpacas.
PROCEDURES The shoulder joint, elbow joint, carpal, and metacarpophalangeal (MCP) joints of the forelimbs and the hip joint, stifle joint, tarsal, and metatarsophalangeal (MTP) joints of the hind limbs were investigated. Each articulation was measured with a universal goniometer by 2 observers, who each obtained 2 measurements when each joint was maintained in standing extension and in maximal passive flexion. Two sample (unpaired) t tests were performed for comparisons of mean standing extension and maximum passive flexion angles between alpacas and llamas. Intraclass correlation coefficients were calculated for each articulation to assess interobserver and intra-observer reliability of measurements.
RESULTS Llamas had larger mean standing extension angles than alpacas for the tarsal and elbow joint, but there were no significant differences between species for all other joints. For all joints, flexion measurements did not differ significantly between the 2 species. For most joints, the reliability of goniometric data between observers was good to excellent (intraclass correlation coefficients, 0.6 to 0.95)
CONCLUSIONS AND CLINICAL RELEVANCE Except for the elbow joint and tarsus in extension, the angle of limb articulations during flexion and extension can be considered similar for alpacas and llamas. These measurements have relevance for veterinary surgeons when assessing joint mobility and conformation and determining appropriate angles for arthrodesis.
Objective—To determine the morphologic and biochemical characteristics of hyperextension of the metacarpophalangeal and metatarsophalangeal joints in llamas.
Animals—12 adult llamas (6 with bilateral hyperextension of the metacarpophalangeal or metatarsophalangeal joints and 6 age- and sex-matched control llamas).
Procedures—Llamas were evaluated by use of lameness examination, ultrasonography, and radiography. A CBC, serum biochemical analysis, and determination of concentrations of trace minerals in serum and liver samples were performed. Llamas were euthanized, and samples of the superficial digital flexor tendon, deep digital flexor tendon, and suspensory ligament were obtained from 4 areas and snap-frozen in liquid nitrogen or suspended in neutral-buffered 10% formalin. Immunohistochemical evaluation of collagen types I and III and assays for measurement of lysyl oxidase activity were performed.
Results—2 affected llamas had a visible gait deficit associated with metacarpophalangeal joint hyperextension. Radiographic evidence of osteoarthritis was detected in 1 severely affected llama, and ultrasonographic changes of soft tissue mineralization and suspensory desmitis were observed in 2 llamas. Liver concentrations of copper were lower and serum concentrations of zinc higher in affected llamas, compared with values in control llamas. Lysyl oxidase activity and collagen distribution did not differ significantly between groups.
Conclusions and Clinical Relevance—Hyperextension of the metacarpophalangeal or metatarsophalangeal joints in llamas does not appear to be the result of injury or degeneration of the suspensory ligament or flexor tendons. Lower copper concentrations coupled with higher zinc concentrations in affected llamas may be indicative of secondary copper deficiency.
Objective—To determine molecular changes in the
expression of insulin-like growth factor-I (IGF-I) and
transforming growth factor-β1 (TGF-β1) in horses with
osteochondrosis, and to characterize expression of
matrix aggrecan and collagen types I, II, and X in articular
cartilage of affected joints.
Sample Population—Articular cartilage from affected
stifle or shoulder joints of 11 horses with naturally
acquired osteochondrosis and corresponding joints of
11 clinically normal horses.
Procedure—Harvested specimens were snap frozen
in liquid nitrogen, and total RNA was isolated.
Specimens were fixed in 4% paraformaldehyde for
histologic examinations. Expression of matrix molecules
was assessed by analysis of northern blots and
in situ hybridization, using equine-specific cDNA
probes and riboprobes, respectively. Expression of
IGF-I and TGF-β1 was assessed by use of noncompetitive
quantitative polymerase chain reaction, in situ
hybridization, and immunohistochemical analysis.
Results—Cartilage obtained from osteochondrosis
lesions had significantly greater expression of IGF-I,
compared with normal cartilage. Expression of TGF-
β1 and collagen type I were higher, but not significantly
so, in affected tissues. Expression of aggrecan
or collagen types II and X did not differ between
affected and clinically normal cartilage.
Conclusions and Clinical Relevance—Increased
expression of growth factors and collagen type I was
found in cartilage from osteochondrosis lesions.
However, this probably reflects a healing response to
injured tissue rather than a primary alteration.
Therefore, methods aimed at altering concentrations
of growth factors in cartilage of growing horses
would be unlikely to alter the incidence or progress of
the disease. (Am J Vet Res 2001;62:1088–1094)
Objective—To determine the mRNA expression of
bone morphogenetic protein (BMP)-6 and -2 and a BMP
antagonist (Noggin) in horses with osteochondrosis.
Sample Population—Samples of articular cartilage
from affected stifle or shoulder joints of 10 immature
horses with naturally acquired osteochondrosis and
corresponding joints of 9 clinically normal horses of
similar age; additionally, samples of distal femoral
growth plate cartilage and distal femoral articular cartilage
were obtained from a normal equine fetus.
Procedure—Cartilage specimens were snap-frozen in
liquid nitrogen, and total RNA was isolated. Adjacent
specimens were fixed in 4% paraformaldehyde for
histologic examination. Expression of BMP-6, BMP-2,
and Noggin mRNA was evaluated by real-time quantitative
polymerase chain reaction (PCR) assays. Spatial
tissue mRNA expression of BMP-6 was determined
by in situ hybridization.
Results—Nucleotide sequences were obtained for
portions of the BMP-6 propeptide and mature peptide
region, as well as the signal and mature peptide region
of Noggin. Expression of BMP-6, BMP-2, and Noggin
mRNA was found to be similar in cartilage from normal
and osteochondrosis-affected horses. Spatial expression
of BMP-6 correlated with the middle and deep layers
of articular cartilage; no differences were observed
in overall expression between cartilage specimens
from the 2 groups of horses. No expression of BMP-6
was found in the superficial layer, subchondral bone, or
osteochondrosis-affected cleft fibrous tissue.
Conclusions and Clinical Relevance—Although these
signaling peptides may play important roles in cartilage
differentiation, results did not provide evidence to suggest
that they are involved in the disease process of
osteochondrosis. (Am J Vet Res 2004;65:110–115)
Objective—To characterize serum trace mineral, sex steroid hormone, and vitamin D concentrations and identify factors associated with metacarpophalangeal and metatarsophalangeal hyperextension in llamas and alpacas.
Samples—Serum samples from 79 llamas and 15 alpacas and owner survey data for 573 llamas and 399 alpacas.
Procedures—Serum samples were stored at −20°C until analysis and were evaluated for trace mineral, vitamin D, estradiol, progesterone, and testosterone concentrations. Information regarding age of onset, number of affected animals in herd, feed and supplements given, type of housing, and management practices was obtained in an owner survey.
Results—Higher serum zinc and iron concentrations were associated with metacarpophalangeal and metatarsophalangeal hyperextension in camelids, compared with controls. In summer and fall months, vitamin D concentrations were significantly higher in affected camelids than controls. Overall prevalence was 13.3% in llamas, compared with 0.7% in alpacas. No management factors were found to be predictive of this condition. No other factors examined were associated with metacarpophalangeal and metatarsophalangeal hyperextension.
Conclusions and Clinical Relevance—Despite similar supplementation practices and environmental conditions between affected and unaffected animals, an association of high serum zinc, iron, and vitamin D concentrations in affected camelids, compared with controls, may indicate differences of intake or absorption of dietary supplements.