Orthopaedic disease Flashcards

Question

Corrective ostectomy

Answer 1

Reconstruction Foals with closed growth plates or severe diaphyseal deformities Very rarely done

Answer 2

Abnormal angulation of the limb in the sagittal plane (flexed or extended) Primarily soft tissue vs. ALD primarily bone Forelimbs most often affected Can be in one or more limbs

Answer 3

Persistent hyperflexion Can have tendon contracture as a result of scarring from tendon injury—seen in adults and rare in foals

Answer 4

Elongation of tendinous unit in relation to bone Congenital · Birth up to 1 month · Carpus or MCPJ most commonly · Teratogenic · Intrauterine positioning · Genetics Acquired · 1-6 months · DIPJ and MCPJ most commonly · Nutrition · Trauma · Infections

Answer 5

Mostly multifactorial and difficult to explain Intrauterine malpositioning with large foals Diseases acquired by the mare in pregnancy: □ Locoweed/hybrid sudan grass □ Gene mutation in sire □ Influenza □ Defects in cross linking of elastin and collagen □ Glycogen branching enzyme deficiency (QH foals)

Answer 6

Good prognosis if can straighten and no osseous changes—guarded if not

Answer 7

Rads: helps rule out any bony abnormalities Conservative: □ Mild cases usually resolve with limited exercise □ Need further treatment if don’t improve or unable to stand ® Splints/casts ® Toe extensions – be careful! ® Analgesics ® IV Oxytetracycline: ◊ Popular treatment to relax tendons (Possibly via Inhibition of collagen gel contraction by myofibroblasts) ◊ Very useful in mild to moderate cases—not as rewarding with severe cases

Answer 8

Fetlock dropped and toe may rise; severe if plantar/palmar region on the ground Can range from mild to severe Caused by flaccid flexor muscles Corrects often within a few weeks with increased muscle tone

Answer 9

If needed protect skin place heel extensions mild exercise

Answer 10

DIPJ - distal interphalangeal joint MC/MT - metacarpa/metatarsal

Answer 11

Due to DDFT Stage 1: wall not passed vertical plane Stage 2: wall passed vertical; worse prognosis

Answer 12

Controlled exercise with Physiotherapy Analgesics—address underlying cause of pain Elevate heel to ease DDFT tension; Toe extension may be useful or cause more pain Surgery: □ ALDDFT desmotomy if unresponsive to medical treatment □ DDFT tenotomy if very bad or doesn’t respond to all other treatments first

Answer 13

May be due to DDFT or SDFT (palpate which under tension—difficult)

Answer 14

Controlled exercise with Physiotherapy Analgesics—address underlying cause of pain Elevate heel to ease DDFT tension; Toe extension may be useful or cause more pain +/- splints with caution (can cause sores) Surgery: □ If no response to medical treatment or >180* □ ALDDFT desmotomy and/or AL SDFT

Answer 15

Enlarged physis Usually painful on palpation Variable lameness; may be reluctant to stand

Answer 16

Clinical signs

Answer 17

Irreguar/wide growth plate; may see sclerosis

Answer 18

Stall rest/restrict exercise Nutritional balance/no gain NSAIDs

Answer 19

A number of conditions often related that affect the immature skeleton Includes: ○ OC/OCD, SCBC ○ ALD/FLD ○ Physitis ○ Cervical vertebral malformations

Answer 20

Occurs at transition from weight bearing to non weight bearing Causes clinical disease in 5-25% of cases High incidence in TB, WB, SB OCD (OC Dissicans occurs when cartilage and/or subchondral bone loose or detaches from joint)

Answer 21

Found underneath the cartilage in a weight bearing area of joint Caused by in folding of weakened cartilage

Answer 22

Complex aetiology and not well understood Essentially a disturbance of endochondral ossification § Causes cartilage in joints to form abnormally § Cartilage and subchondral bone become irregular in thickness and weak § May develop cartilage and bone flaps that may remain partially attached to the bone or break off and float around in the joint - OC to OCD § causes inflammation in the joint and over time may lead to the development of arthritis. Dynamic lesions and change over time

Answer 23

Age: young Genetics: Risk of OCD may be partially inherited Rapid growth and large body size Nutrition: Diets very high in energy or have an imbalance in trace minerals (low copper diets) Metabolic activity/Hormonal imbalances: Insulin and thyroid hormones Trauma and exercise: Trauma (including routine exercise) is often involved in the formation and loosening of the OCD flap

Answer 24

Often have no clinical signs and found on screening radiographs incidentally Persistent joint effusion in a young horse May occur when very young or only when into work Lameness, if present, varies with location and severity (usually sound at a walk)

Answer 25

Clinical signs Radiographs § Often bilateral (>50% of cases) § always radiograph the opposite limb § Various radiographic signs Ultrasound § Some lesions may not be seen on radiographs if only cartilage is affected

Answer 26

Tarsocrural joint Femoropatellar joint Fetlock

Answer 27

1. Distal intermediate ridge of the tibia (DIRT) 2. lateral trochlear ridge 3. medial malleolus More common in SB and WB ○ Can be ID arthroscopically without radiographic evidence Treatment ○ Arthroscopic removal ○ Early better so not OA Prognosis ○ Fair to good

Answer 28

Femoropatellar joint: 1. Lateral trochlear ridge (best seen on lateral oblique view) 2. Medial trochlear ridge 3. Distal patella More common in TB Radiographs ○ Often, flattening of trochlear ridges US ○ Can be useful for MTR lesions that cannot be seen radiographically Treatment ○ Generally lesions monitored until >9 months and then possibly surgery - arthroscopic debridement Prognosis ○ Better prognosis with lesions <2cm; worse with >4cm

Answer 29

Fetlock 1. Sagittal ridge of distal MC/MT III 2. Dorsoproximal P1 (considered traumatic in origin) 3. Palmar/plantar P1 (considered traumatic in origin) HL and FL affected Radiographs ○ Fragments and flattening Prognosis depends on location - dorsal good, palmar/plantar poor

Answer 30

Can only be expected to be successful in either very young animals or in very mild cases (Single small lesions without effusion or lameness) Rest, controlled exercise, +/- NSAIDs, +/- IA corticosteroids

Answer 31

Arthroscopic debridement □ Horses >1 year ideally (to give some lesions a chance to heal; sooner may debride too much bone) Surgery indicated if horse meets two of the following criteria □ Joint effusion □ Lameness localised to the joint □ Radiographic evidence

Answer 32

Part of osteochondrosis complex Found underneath the cartilage in a weight bearing area of joint vs. at transition zone for OC Caused by in folding of weakened cartilage

Answer 33

Stifle (medial femoral condyle) Phalanges Can be found anywhere

Answer 34

TB : Mostly young at onset of training (1-3y) WB: Often with OA—poorer prognosis

Answer 35

Often present with lameness with or without effusion Size of lesion and amount of cartilage involved correlated with clinical signs and prognosis

Answer 36

Often block with IA anesthesia Radiographs: □ Radiolucent areas of bone often accompanied by thin sclerotic rim □ Size of lesions vary from flattening, to slight indentation, to round lesions □ Always radiograph both limbs or other joints that are effusive □ Usually able to ID, but may need CT

Answer 37

Rest, NSAIDs IA or Intralesional corticosteroids (under US or arthroscopic guidance)

Answer 38

Moderate to severe cases Newer techniques: □ Trans cyst lag screw placement: Thought to compress and stimulate bone formation—recently much better success with improved technique using this method □ Absorbable Implants: Very promising success with improved soundness

Answer 39

Joint instability ○ soft tissue injury Intra articular fracture Synovitis/capsulitis Synovial sepsis Subchondral bone disease Previous OCD/Bony cysts

Answer 40

Disorder of movable joints Characterised mainly by articular cartilage degeneration and loss ○ With or without changes to the synovium or subchondral bone ○ Result of complex biological and mechanical processes Abnormal mechanical load, inflammation and metabolic tissue failure (anabolic repair overwhelmed by catabolic process)

Answer 41

Low grade, chronic, often bilateral lameness Lameness may improve with work Joint effusion typically present (not the TMTJ) +/- decreased range of motion +/- positive to flexion

Answer 42

Periarticular enthesophytes and osteophytes ○ Enthesophytes - at the attachment of a tendon or ligament ○ Osteophyte - at the joint margin Narrow joint space Subchondral bone sclerosis or lysis May see osteochondral fragments along with osteoarthritic changes if fragments are potentially chronic/diagnosed late

Answer 43

Distal interphalangeal joint (DIPJ-coffin joint) Metacarpophalangeal joint (MC/MTPJ-fetlock joint) Proximal interphalangeal joint (PIPJ-pastern joint) Carpus Tarsus Stifle

Answer 44

Relatively common cause of forelimb lameness May be due to extensor process fracture of P3, septic arthritis

Answer 45

Often bilateral, mildly positive to distal limb flexion Worst on the inside of a hard circle Effusion at coronary band Mature sports horses and leisure horses Common FL Improve to a PDNB, sound after ASNB

Answer 46

Often block to a PD but sometimes blocked out with Abaxial Most specific diagnosis blocking to the DIPJ Radiographs often display subtle changes to extensor process

Answer 47

“High ringbone” Moderately common cause of forelimb lameness (can also occur in hind limb) Young horses may have induced by OC Sport horses, heavy breeds, hunters

Answer 48

Often palpable enlargement of PIPJ Insidious onset unless secondary to fracture; usually gets worse with work Less commonly bilateral Worst on the inside of a hard circle Positive to distal limb flexion Firm bony enlargement of pastern (not effusion)

Answer 49

Often blocks to abaxial sesamoid Radiographs display OA changes often Usually negative PDNB, positive ASNB PIPJ block most diagnostic

Answer 50

Common in athletic horses; often race horses Can be caused by OC, fragmentation from OCD or SCBL § Dorsoproximal P1 § Dorsal sagittal ridge Can be caused by traumatic fracture § Palmar/plantar General wear and tear

Answer 51

Usually forelimb, usually effusion usually palpable Can lead to moderate-severe unrelenting lameness Often bilateral

Answer 52

Blocks usually to fetlock IA Rads: Can cause development of periarticular osteophytes, enthesophytes and joint space collapse (usually medially) Consider developmental diseases too!

Answer 53

Specific osteoarthritic/subchondral bone disease of the fetlock Results from accumulated stress and sclerosis during racing Sclerosis in palmar region of condyle Moderate to severe lameness Predisposes to condylar fracture

Answer 54

Radiographs: · Sclerosis of some kind present within the palmar aspect of the condyle · Can see intense sclerosis of the palmar region of the condyle, potentially deep to a lytic lesion · can appear as variously shaped palmar defects with or without secondary arthritis changes present Scintigraphy · Sensitive for detecting early stress fracture and bony deposition forming the sclerotic zone within the palmar region of the condyle · Early recognition helpful to reduce sclerosis and allow remodeling vs. progression into condylar fracture CT and MRI · More sensitive means vs. rads for detection early

Answer 55

Rest with controlled exercise Corticosteroids IA

Answer 56

Very common in currently racing or previously raced TB, more rare in other breeds (older typically) Radiocarpal (RC) and middle carpal (MC) joints most commonly - Less commonly CMC - Affects the two high motion joints of the carpus

Answer 57

Usually chronically thickened joint capsule and decreased ROM Moderate to severe lameness

Answer 58

Often very performance limiting as progress to chronic OA quickly Can be acute trauma related, but often due to chronic stress and adaptive remodeling Dorsal distal radiocarpal bone most common May find palmar fragments (more often due to overt trauma)

Answer 59

Osteoarthritic process Due to chronic stress and adaptive remodeling Sclerosis of the radial facet of C3 Often progresses to slab fracture, which leads to chronic OA Usually can diagnose on CS and radiographs, but sometimes NS or CT assists for earlier diagnosis and prevention of further injury

Answer 60

Easily localised with intra-articular blocks

Answer 61

OA of the distal hock joints in the most common cause of hindlimb lameness in the horse Distal intertarsal joint (DIT) and tarsometatarsal (TMT) joint most common = “Bone Spavin” Less common PIT (if occurs, typically associated with trauma/fractures/previous sepsis)

Answer 62

Sport horses, western performance and standardbreds most prone Poor conformation a contributing factor (Often sickle hocked) - causes abnormal loading of small tarsal bones Foals can be predisposed due to incomplete ossification of tarsal bones poorly managed

Answer 63

May present as a back problem or poor performance Mild-severe lameness □ Most lame on the inside of a hard circle □ Sometimes undetectable because bilateral □ Sometimes history undetectable lameness but deterioration of attitude Toe dragging/reluctant to flex tarsus Short cranial phase of stride Pain on back palpation May appreciate new bone formation, but hard to appreciate any joint distension May warm out of it May be positive to flexion

Answer 64

Clinical signs Blocks: TMT joint local anesthetic has been shown to diffuse into the DIT joint, therefore some clinicians only block and treat this joint □ Complete resolution may not occur with blocking and a 50% improvement is considered significant Radiographs: □ Commonly bilateral so radiograph both □ Lameness can exist with little to no radiographic changes □ Also there can be extensive changes with no lameness □ May see osteophytosis or sclerosis and/or lysis □ Poor sensitivity, so believe the blocks NS: correlates well with MRI lesions MRI: very useful for tarsus as rads often have a low sensitivity

Answer 65

All breeds and types Occurs typically secondary to trauma or injury

Answer 66

Very positive to proximal limb flexion Most lame on outside of a soft circle IA blocks § Should block all three compartments (MFT, LFT, FP) Radiographic changes typically seen later in the disease § First sign often osteophyte formation of the medial tibial plateau and intercondylar eminence § Narrowing of joint space interpreted with caution due to positioning of radiograph May need diagnostic arthroscopy to make a diagnosis § Blocks to IA anesthesia or scintigraphy positive, but rad/US negative good candidates Evaluate for possible initiating cause § ie. Meniscal tears § may need US or diagnostic arthroscopy

Answer 67

NSAIDs IA corticosteroids Weak anti-inflammatories Autologous biologics/'regenerative' medicine

Answer 68

Phenylbutazone, firocoxib Risks of toxicity -> right dorsal colitis Only palliative and should be limited to acute phase; firocoxib likely more safe for long term use

Answer 69

Justifiable and clinically effective form of joint medication Can have detrimental effects on normal cartilage (suppress chondrocyte activity) Not the case in inflamed or abnormal joints (chondroprotective in low doses) Methylprednisolone acetate (Depo-Medrone) - used least Triamcinolone acetonide (Adcortyl) - used most Often expect about 3-6 months of pain relief or longer ideally—not uncommon for horses to be injected twice yearly Caution § Iatrogenic sepsis: § Corticosteroid induced laminitis Dosing recommendations: □ Triamcinolone - 18mg - 2000 cases treated with 20-45mg of triamcinalone = 0.15% cases of laminitis (all but 1 were ponies) □ Methylprednisalone - 200mg

Answer 70

IA hyaluronic acid (HA) - notmal component of joint fluid - never given on its own PSGAGs - IM/SQ - Chondroitin sulfate Pentosan (Pentosan or cartrophen) - beechwood hemicellulose

Answer 71

Evidence is poor Unlikely to work if corticosteroids didn't Consider for laminitis risk horses IRAP (interleukin receptor antagonist protein) PRP (platelet rich plasma) Stem cells (allogenic or autogenic)

Answer 72

Diagnostic arthroscopy Surgical arthroscopy Abrasian arthroplasty Microfracture Ankyloisis/atrodesis

Answer 73

Used commonly for the stifle as other diagnostics can be limiting Allows for the simultaneous diagnosis and treatment of some pathology (i.e. cartilage fibrillation, meniscal tears) Only an option for high motion joints

Answer 74

Removal of OC fragments if present Articular cartilage debridement Reconstruction of IA fractures Joint resurfacing

Answer 75

Stimulates endogenous repair Debridement of SCB plate disease tissue to allow for healing Replaced with fibrocartilage

Answer 76

Fusion of the joint

Answer 77

Rids the bone of diseased and unstable articular cartilage in order to fuse the bones together—this alleviated instability and pain Salvage procedures Warranted in horses with OA that are no longer responsive to medical management or have overt damage or pain that may be alleviated with fusion intervention.

Answer 78

Destroying articular cartilage to encourage self fusion Low motion joints typically (i.e. distal hock joints>>PIPJ) Goal = athletic performance Types: – Chemical: Ethyl alcohol - Trans-articular surgical drilling/curettage of cartilage

Answer 79

Destroying articular cartilage and surgical stabilization to aid in fusion Can perform in low or high motion joints Much more expensive than ankylosis Complication rates much higher Reasons to perform: - Performed with OA in some cases (PIPJ common) - Performed with soft tissue injury, septic arthritis, fractures Types: - Transarticular screws alone screw/plate