VETcpd - Orthopaedics Peer Reviewed Lameness in the Juvenile Dog - Part 1: Developmental diseases

Developmental diseases, those that cause lameness in the skeletally immature dog, are relatively common. A structured approach is required to achieve a diagnosis, as with the adult dog. However, given the potential for some of these conditions to have an impact on future joint health, prompt diagnosis and treatment may be of greater importance. Differentials for lameness in the skeletally immature dog include hip dysplasia, elbow dysplasia, osteochondrosis and Legg Calve Perthes disease. Surgery to treat hip dysplasia in the juvenile dog may be possible depending on the age of the animal at presentation and the severity of the disease. Similarly, there is an emphasis on early debridement of osteochondrosis or coronoid disease lesions to give superior outcomes. There is little evidence that restriction of exercise Philip Witte will reduce the impact of future osteoarthritis, so the historical emphasis on a BSc BVSc CertAVP(GSAS) combination of rest and analgesia should be considered secondary to achieving DSAS(Orth) MRCVS a prompt diagnosis. RCVS Specialist in Small Animal Surgery Key words: Dog, juvenile, developmental, hip dysplasia, elbow dysplasia, (Orthopaedics) osteochondrosis, avascular necrosis, Legg Calve Perthes, osteoarthritis Philip graduated from the University of Bristol in 2005. He worked in rural Introduction mixed practice prior to completing a This two-part series of articles focus on may negatively influence a young dog’s surgical internship in 2009 and an lameness affecting the forelimbs and/or behavioural development. This first orthopaedic residency at Southern hind limbs of dogs that have not reached article covers the developmental diseases Counties Veterinary Specialists skeletal maturity. Some conditions, such of the canine musculoskeletal system. in 2013. He received the RCVS as those associated with physes, are certificate in advanced veterinary unique to the skeletally immature patient, Approach to the practice (general small animal surgery) whilst for other conditions the treatment skeletally immature dog in September 2013 and the RCVS options and prognosis may differ from with lameness the adult. A number of developmental diploma in small animal orthopaedics History in 2018. He is currently the head diseases are common causes of lameness in the dog. Conditions that cause The approach to lameness in the skeletally surgeon at Cornwall Veterinary immature dog begins (as for any case) with lameness in the juvenile dog have been Referrals. His interests include trauma taking an accurate history. If the onset was grouped for the purposes of these articles management and angular limb acute then a trauma may be suspected. as follows: deformity correction. However, clients will often ascribe • developmental diseases of the lameness to some relatively minor trauma musculoskeletal system, (falling whilst running, for example), • angular limb deformities associated and it is important to recognise that a with physeal disruption, number of dogs presenting this way will • traumatic injuries specific to the have underlying subclinical disease which juvenile dog, may not manifest itself until exacerbated. • miscellaneous conditions (panosteitis, Additionally, a number of conditions metaphyseal osteopathy, physeal that cause lameness in young dogs can dysplasia, osteogenesis imperfecta, affect them bilaterally, which may not hyperparathyroidism and be recognised as a result of its symmetry. craniomandibular osteopathy.) Unilateral lameness is more recognisable for clients but may not be present until It should also be noted that a measured exacerbated, again by relatively minor approach to exercise modulation is trauma to one or other limb. required for the juvenile dog. Strict exercise restriction for extended Gait examination periods is inappropriate, particularly It is useful to ask a client which limb they during the sensitive window relating think is affected by lameness. However, SUBSCRIBE TO VETCPD JOURNAL to the development of confidence and unless they can confidently identify the emotional competence (weeks 3 to limb affected by, for example, intermittent Call us on 01225 445561 14 of life, Morrow et al. 2015). The non-weight-bearing lameness, a gait or visit www.vetcpd.co.uk orthopaedic surgeon should remember examination is critical to identify the limb that limited opportunity for socialisation (most) affected.

Page 32 - VETcpd - Vol 8 - Issue 3 VETcpd - Orthopaedics A B C Definitive diagnosis Triple and (increasingly favoured) double osteoarthritis was significantly lower (or A genetic test is available from Idexx pelvic osteotomy (PO) techniques also absent) for hips treated with double PO Laboratories to detect seven DNA aim to externally rotate the acetabula. compared with untreated hips (Jenkins sequences that have been associated In PO techniques the altered acetabular and others 2020). with canine hip dysplasia in Labrador alignment is achieved through osteotomies of the ilium (which is plated with Elbow dysplasia Retrievers. Note that this test is only For a thorough discussion of elbow relevant to this breed. Use of this test a specific plate and screws inducing torsion) and pubis (the ischium is dysplasia see Craig and Witte 2017a, b, c. alone to select candidates for intervention Elbow dysplasia is a term used to describe (see juvenile pubic symphysiodesis below) also osteotomised in the triple pelvic a few developmental conditions of the has been suggested but is controversial, osteotomy, Figure 2). Candidates for PO elbow which result in osteoarthritis. one perspective being that surgery should are typically over 18 weeks but under 10- • Medial coronoid disease is the most be reserved for dogs with relevant disease, 12 months of age. common form of elbow dysplasia. not a specific complement of genes. Candidates are selected for PO procedures • Osteochondrosis of the medial part of Imaging is typically performed to on the severity of their clinical signs. In the humeral condyle (capitulum) confirm the diagnosis. Coxofemoral addition, the absence of radiographic is reasonably rare, and is often subluxation is analysed in a well- evidence of osteoarthritis is a selection concurrent with medial positioned dorsoventral radiographic view criterion, as this is taken to indicate joints coronoid disease. of the pelvis with hips extended (Figure in which degenerative joint disease has 1) using the Norberg angle and/or the not advanced to such a stage that its • Ununited anconeal process is rare. Figure 1A: The ventrodorsal view of the pelvis with hips extended is used to assess coxofemoral alignment and peri-articular new bone formation. Figure 1B: Measurement • Incongruity refers to either a step in of the Norberg angles is shown: three lines are drawn: two connecting the centre of the femoral heads and cranial acetabular rims, one connecting the centres of percentage of dorsal acetabular coverage clinically relevant progression is imminent both femoral heads. The Norberg angles should be greater than 95o. Figure 1C: The percentage of dorsal acetabular coverage of the femoral heads is shown: an of the femoral head (which should be regardless of any intervention. The the loaded joint surface formed by approximate circle is drawn over the femoral head (blue) and the dorsal acetabular rim identified (red). An estimate is made of dorsal acetabular rim coverage, which greater than half of the femoral head). As severity of laxity is determined prior to the radial head and adjacent coronoid should be greater than 50%. In this case it is significantly below 50% indicating coxofemoral subluxation. osteoarthritis advances, cranial acetabular intervention using a dynamic radiographic process or a mismatch in the radii of rim sclerosis, curvilinear osteophytosis study (such as PennHIP) and the angles curvature of the trochlea (lateral part of on the femoral neck (Morgan line) and of reduction (which give an indication of the humeral condyle) and the trochlea Gait examination for the skeletally reducing again and restoring normal soft tissues which maintain the articulation peri-articular new bone formation are laxity) and subluxation (which gives an (articular groove of the ulna between immature dog follows the same pattern as quadriceps function. between the femoral head and acetabulum. recognised. Where the ventrodorsal hip indication of dorsal acetabular rim wear). the coronoid and anconeal processes). for an adult dog, although the immaturity Coxofemoral reduction is maintained Physical examination extended radiographic view fails to Hips in which moderate to severe laxity is Temporary or permanent incongruity has brings with it additional challenges. The primarily by the soft tissues crossing the present are unlikely to benefit from either The purpose of the physical examination confirm coxofemoral subluxation or been hypothesised to be a link between dog is viewed walking and/or trotting joint and to some degree by hydrostatic is to more specifically identify the source peri-articular new bone formation in of these procedures and, where lameness is some of these conditions, as it has been away from and toward the viewer. Young pressure in the film of joint fluid interposed of discomfort which is to blame for the dogs over four months of age, a dynamic severe, joint replacement (or femoral head theorised that inappropriate loading of the dogs are often boisterous and difficult between the articulating surfaces of the lameness. Physical examination involves hip study may be indicated, such as the and neck ostectomy) may be indicated. articular surfaces may be implicated in the to control on a lead. The most useful femoral head and acetabulum. From palpation of the muscles, bones and joints PennHIP (Pennsylvania Hip Improvement Outcomes for double pelvic osteotomy aetiology. However, this remains highly component of such a gait examination approximately four months of age, laxity followed by manipulation of the joints. Program, Antech Imaging). Manipulative have been reported in a number of recent controversial and the aetiology of these may be the few steps it takes for the dog Palpation of the muscles will determine within the joint begins to become apparent tests such as the Ortolani, Barden and studies, including a recent study showing conditions remains uncertain. to circle the client when turning around whether there is asymmetry between in affected dogs. Barlow manoeuvres are most reliable and that the radiographic progression of to return. It is reasonable to ask the client The consultation forelimbs or hind limbs, in which atrophy welfare-friendly when performed under to repeat a walk a few times in order to The consultation History: Dogs will show forelimb lameness, – or more correctly, depending on the sedation or general anaesthesia and may be be certain which limb is affected. With History: Only in very severe cases which may be most apparent after rest age of the animal, hypotrophy, – gives sufficient to detect coxofemoral laxity. forelimb lameness, the head nods down of coxofemoral laxity, i.e. cases with following exercise. Typically, lameness is information regarding the affected limb when the unaffected (or less affected) subluxation (sometimes termed ‘luxoid Treatment present from around eight months of age; and the severity/duration of the condition. forelimb is placed and the head is lifted hips’), will lameness become apparent Surgical interventions to address hip however, dogs may not present for several Palpation of the elbow, stifle, carpus and up when the affected limb is placed. With around four months of age; dogs more dysplasia in the skeletally immature dog months as a result of the very intermittent/ tarsus, as well as the metacarpophalangeal hind limb lameness the gluteal muscles on typically present from eight to nine are intended to improve loading of the episodic clinical signs. and interdigital joints, may reveal the unaffected limb undergo a greater up months old. However, upon questioning, femoral and acetabular articular surfaces effusion compared with the contralateral Gait examination: forelimb lameness and down excursion (‘hip hike’). clients may be aware of ‘bunny hopping’ by increasing the area of contact and side. Palpation of the bones may reveal may be present. when running and an awkward sitting reducing dynamic reduction/subluxation The appearance of the lameness does not resentment (particularly in cases of elbow effusion posture in which the hips are flexed, suggested to be present with every stride. Physical examination: give any more information than which panosteitis). Manipulation of joints may the stifles extended and the weight Current techniques aim to rotate the is most easily palpated caudo-distal to limb is affected. The belief that a gait reveal resentment. Reduced ranges of born asymmetrically onto one or other acetabulum externally such that more of the lateral part of the humeral condyle. examination can distinguish between motion are unlikely to be present as a ischiatic tuberosity. the acetabular articular surface is located Palpation may also reveal unilateral shoulder and elbow pain, for example, result of osteoarthritis in young dogs since Gait examination: this may reveal hind dorsal to the femoral head. forelimb muscle atrophy, most easily is misplaced. Two exceptions exist: in peri-articular fibrosis is unlikely to have limb lameness and/or bunny hopping at palpated over the shoulder joint where the case of gracilis myopathy (not a developed to any great level. Juvenile pubic symphysiodesis is an option the acromion process may be more condition of the skeletally immature a trot. for young dogs with significant remaining prominent. Manipulation of the elbow, in dog) or in patellar luxation. In the latter Physical examination: palpation may growth potential (less than 18 weeks for Developmental diseases Figure 2: Bilateral single session double pelvic particular extension, may be resented. case, there is sometimes the report of of the canine reveal asymmetry within the gluteal and medium to large breed dogs, Bernarde osteotomy was performed in a six-month-old non-weight-bearing lameness for a few proximal intrinsic muscles of the hind 2010). This procedure aims to halt growth cocker spaniel. At eight-week follow-up, the above Definitive diagnosis strides with the hip and stifle extended musculoskeletal system limbs. Hip manipulation, in particular in the midline of the pelvis through radiograph (ventrodorsal with hind limbs in frog- Imaging is critical in order to confirm prior to resumption of a normal gait. This Hip dysplasia extension, may be resented. See below for electrocautery of the pubic symphyseal leg position) shows union of the ilial osteotomies. elbow dysplasia and diagnose the specific Femoral head coverage should not be evaluated pattern is widely assumed to be associated For a thorough discussion of canine hip the continuation of the examination with cartilage such that continued growth in this view; however, subjectively, it may be condition. Note that in certain breeds with the patella becoming fixed for that dysplasia see Witte and Scott 2016. Canine more specific tests with the dog under dorsally will result in external rotation of appreciated that there is increased ventroversion of (notably English Springer Spaniels, short period in a luxated position, before hip dysplasia is associated with laxity in the sedation or general anaesthesia. the acetabula. the acetabula in comparison with the normal dog. Rottweilers and Labrador Retrievers)

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