Developmental orthopedic illness (DOD) refers to a radical of conditions caused by congenital and biology factors that impact the appendicular skeleton of young dogs and effect successful lameness.1,2 They tin beryllium identified by considering the patient’s signalment and past and conducting a implicit carnal and orthopedic introspection and a differential diagnosis. Although the diseases that autumn nether the umbrella word alteration wrong the literature, this nonfiction focuses connected the communal developmental conditions that effect successful lameness: panosteitis, hypertrophic osteodystrophy, and endochondral ossification disorders. Hip dysplasia, patellar luxation, and angular limb deformities are beyond the scope of this series.
Panosteitis
Panosteitis is simply a self-limiting inflammatory illness of the marrow of agelong bones that historically has been referred to arsenic eosinophilic panosteitis, juvenile osteomyelitis, enostosis, and shifting limb lameness.2-5 Its etiology is unknown, but it appears that macromolecule accumulation (from fare oregon inflammation), vascular proliferation, and section bony enactment astatine nutrient foramina pb to increases successful intraosseous unit and objective signs.2 The incidence of panosteitis has been estimated astatine 2.6 cases per 1000 patients,2,6 and is highest successful the Northeast and North Central United States, with cases much communal successful summertime and fall.2
Panosteitis chiefly affects ample and elephantine canine breeds but tin impact smaller ones arsenic well. Most patients contiguous with objective signs astatine betwixt 5 and 12 months of age,2-3 and males are much commonly affected than females (4:1 ratio).2 Patients that contiguous with panosteitis are often reported to person a shifting limb lameness. Lameness tin alteration from mild and transient to nonweightbearing lameness, and the forelimbs are much commonly affected than the hindlimbs (4:1 ratio).2,5
Varying degrees of lameness whitethorn beryllium observed upon examination, and sometimes the lameness shifts due to the fact that aggregate agelong bones are affected.2 All agelong bones should beryllium palpated and attraction taken to debar compressing muscular oregon tense structures. Patients typically person marked discomfort connected palpation of affected bones. The astir commonly affected are the ulna (42%), radius (25%), humerus (14%), femur (11%), and tibia (8%).2,3,5
Radiographs should beryllium taken to differentiate panosteitis from different DODs. Radiographic findings alteration based connected the signifier of the disease.2-5 The changes hap successful the diaphysis/metaphysis.2-4 In aboriginal stages (Figure 1), films whitethorn beryllium normal, oregon determination whitethorn beryllium a alteration successful radiodensity adjacent the nutrient foramen.2-4 As the illness progresses (Figure 2), determination is an summation successful medullary opacity with a granular signifier oregon nonaccomplishment of mean trabecular pattern; immoderate patients besides grounds periosteal caller bony formation.2-4 Later on, the medullary canal becomes much diffuse and homogeneous.2-4 After 4 to 6 weeks, the densities regress, and the bony appears to person a courser trabecular pattern.2-4 There is nary correlation betwixt radiographic severity of lesions and objective severity of disease.2,5
Eosinophilia was often reported successful aboriginal descriptions of panosteitis, but consequent studies bespeak that lone 1% to 5% of panosteitis patients person eosinophilia.2,5
Treatment (exercise regularisation and analgesics) is palliative lone and does not power probability of recovery. There is 1 study successful which the usage of benzopyron, a proteolytic substance not disposable successful the US, resulted successful normalization of interosseous unit and objective signs wrong days of administration, but the findings person not been validated.2
Panosteitis episodes tin recur, but severity usually decreases and intervals summation with recurrence.2,5 Overall, the prognosis is excellent, with astir dogs making a implicit recovery.2,3
Hypertrophic osteodystrophy
Hypertrophic osteodystrophy (HOD)—also known arsenic metaphyseal osteopathy, Moeller-Barlow disease, osteodystrophy II, and skeletal, infantile, oregon juvenile scurvy—is seen successful young dogs that are increasing rapidly.2,6,7-8 Its incidence is 2.8 cases per 100,000 patients and is higher successful the US Northeast.2,9 Most commonly, it presents successful the autumn and slightest commonly successful the winter.2
Its etiology is incompletely understood. Vitamin C deficiency, overnutrition, heredity, inflammation/infection, and vaccination person each been proposed, but not validated, arsenic sole causes.2,7-10
Although HOD predominantly affects ample and elephantine breeds, immoderate breed whitethorn beryllium affected.2,7-8 Males are 2.3 times much apt to beryllium affected than females.2
Patients person varying degrees of lameness, from mild to severe, which presents arsenic reluctance to basal and walk.2,7 Palpation of the agelong bones typically reveals warm, achy swelling of the metaphyseal region.2,7 The distal radius, ulna, and tibia are astir commonly affected, but HOD has besides been recovered passim the axial/appendicular skeleton.2,9 It is communal for aggregate bones to beryllium affected.2,7 Systemic signs (inappetence/ anorexia, depression, hyperthermia, and diarrhea) whitethorn travel orthopedic signs.2,7,9
Radiographs corroborate the diagnosis, but objective signs whitethorn look 48 to 72 hours earlier radiographic abnormalities.2 Films (Figure 3) uncover a treble physeal line, a radiolucent enactment successful metaphysis parallel to a constrictive portion of accrued radiodensity instantly adjacent to the physis.2,7-8 Periosteal/endosteal proliferation whitethorn occur.2,7,10 In much precocious cases, radiographs whitethorn amusement excessive enlargement of the metaphyses or, little commonly, irregular widening of the physes.2
HOD is typically self-limiting and resolves wrong days to weeks, but it tin persist for months.2 The prognosis is bully to fantabulous successful mild cases, but decease tin hap successful terrible cases.9 Therapy for the erstwhile includes a balanced diet, oral analgesics, and location care; for the latter, hospitalization and much intensive attraction whitethorn beryllium required. Weimaraners whitethorn respond amended to steroids than to NSAIDs. In 1 study, 100% of Weimaraners treated with oral prednisone (0.75-1.5 mg/kg each 12 hours) achieved objective remission wrong 48 hours, whereas lone 45.5% of those treated with NSAIDs had objective solution wrong the aforesaid clip period.10
One oregon much recurrences of HOD tin make weeks to months aft the archetypal episode. Weimaraners with HOD-affected littermates are much apt to relapse than those without.2,5,8,10
Endochondral ossification disorders
In increasing animals, cartilage wrong the epiphysis and maturation plates becomes bony done a process of matrix mineralization, chondrocyte death, vascularization, and ossification.11-12 In patients with osteochondrosis, the process fails to hap normally.1,11-13 Risk factors for the upset see heredity, accelerated bony growth, diet, and trauma.1,11-13
Although the terminology describing osteochon- drosis is controversial, successful wide terms, it tin beryllium focal oregon multifocal, unilateral oregon bilateral, and asso- ciated with the maturation plates oregon the epiphyses.1,11
It is classified according to severity.13 Osteochondrosis latens lesions are precise aboriginal microscopic abnormalities that tin resoluteness spontaneously without causing important disease.13 Osteochondrosis manifesta lesions are macroscopically and radiographically evident but don’t typically effect successful objective disease.13 Osteochondrosis dissecans lesions hap erstwhile the deformed cartilage separates from the underlying bony and creates flaps successful the joint.13 These lesions, which origin symptom and lameness, are conventionally referred to arsenic osteochondritis dissecans due to the fact that of ensuing synovitis.11,13
Osteochondrosis latens does not necessitate surgical management. Treatment of osteochondrosis manifesta whitethorn beryllium much debatable, but arsenic a sole lesion, it is not typically an denotation for surgery.11 Osteochondritis dissecans is typically a surgical illness and volition beryllium discussed successful Part II of this series.
Jessica R. Kinsey, DVM, DACVS-SA, is simply a 2008 postgraduate of Michigan State University College of Veterinary Medicine. While she considers herself a arrogant Spartan, she presently resides successful New Jersey. Kinsey enjoys each aspects of veterinary surgery, and her circumstantial interests see developmental abnormalities, hepatobiliary surgery, surgical oncology, neurosurgery, and polytrauma/ perioperative absorption of captious cases. In her escaped time, Kinsey enjoys question and outdoor adventures. She shares her location with her husband, daughter, and four-legged companions: Bullwinkle, Gremlin Bear, Sir Tully, and Laser Kittenface.
References
- Richardson DC, Zentek J, Hazewinkel HAW, Nap RC, Toll PW, Zicker SC. Developmental orthopedic illness of dogs. In: Hand MS, Thatcher CD, Remillard RL, Roudebush P, eds. Small Animal Clinical Nutrition. 4th ed. Mark Morris Institute; 2000:505-528.
- Breur GJ, Towle Millard HA. Miscellaneous orthopedic conditions. In: Johnston SA, Tobias KM, eds. Veterinary Surgery: Small Animal. 2nd ed. Elsevier; 2018:1299-1315.
- Montgomery R. Panosteitis. In: Bojrab MJ, Monnet E, eds. Mechanisms of Disease successful Small Animal Surgery. 3rd ed. Teton NewMedia; 2010:570-576.
- Halliwell WH. Tumorlike lesions of bone. In Bojrab MJ, eds. Disease Mechanisms successful Small Animal Surgery. Lea & Febiger; 1993:932-943.
- Lenehan TM, Fetter AW. Panosteitis. In: Newton CD, Nunamaker DM. Textbook of Small Animal Orthopedics. Lippincott; 1985:591-596.
- Johnson JA, Austin C, Bruer GJ. Incidence of canine appendicular musculoskeletal disorders successful 16 veterinary teaching hospitals from 1980 done 1989. Vet Comp Orthop Traumatol. 1994;7(2):56-59. doi:10.1055/s-0038-1633097
- Bellah JR. Hypertrophic osteodystrophy. In: Bojrab J, eds. Disease Mechanisms successful Small Animal Surgery. Lea & Febiger; 1993:858-864.
- Montgomery R. Hypertrophic osteodystrophy successful dogs. In: Bojrab MJ, Monnet E, eds. Mechanisms of Disease successful Small Animal Surgery. Teton NewMedia; 2010:564-569.
- Munjar TA, Austin CC, Breur GJ. Comparison of hazard factors for hyper- trophic osteodystrophy, craniomandibular osteopathy and canine distemper microorganism infection. Vet Comp Orthop Traumatol. 1998;11(1):37-43. doi:10.1055/s-0038-1632606
- Safra N, Johnson EG, Lit L, et al. Clinical manifestations, effect to treat- ment, and objective result for Weimaraners with hypertrophic osteodys- trophy: 53 cases (2009-2011). J Am Vet Med Assoc. 2013;242(9):1260-1266. doi:10.2460/javma.242.9.1260
- Breur GJ, Lambrechts NE. Osteochondrosis. In: Johnston SA, Tobias KM, eds. Veterinary Surgery Small Animal. 2nd ed. Elsevier; 2018:1372-1385.
- Ytrehus B, Carlson CS, Ekman S. Etiology and pathogenesis of osteochon- drosis. Vet Pathol. 2007;44(4):429-448. doi:10.1354/vp.44-4-429
- Ytrehus B, Grindflek E, Teige J, et al. The effect of parentage connected the prevalence, severity and determination of lesions of osteochondrosis successful swine. J Vet Med A Physiol Pathol Clin Med. 2004;51(4): 188-195. doi:10.1111/j.1439-0442.2004.00621.x
English (US)