Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
VMD 460 Orthopedics
Veterinary Orthopedics
| Question | Answer |
|---|---|
| Characterize cortical bone | *limited blood supply *strong dense bone *good implant holding *slow healing |
| Characterize cancellous bone | *excellent blood supply *weaker porous bone *good healing potential *close to bone ends |
| Structural properties of a bone are dependent on what factors? | *size and shape *load *deformation *stiffness |
| What does the slope of the linear portion of a Load-Displacement Curve represent? | stiffness of the bone |
| The point at which the linear portion of Load-Displacement curve levels off is called _____. What does it represent? | *it is called the yield *it represents some structural change to the bone in response to load |
| What is the elastic region of the Load-Displacement curve? | *the region over which displacement of the bone will return to normal once the load is removed *this is the portion of the curve before the yield |
| What is the plastic region of the Load-Displacement curve? | *the region over which displacement of the bone will not return to normal (there is structural change to the bone) *this is the portion of the curve after the yield |
| Yield energy | The energy required to get to the yield point (where the bone's structure starts to get altered in response to load) |
| Failure energy | The energy required to get to the failure point (where the bone breaks) |
| Material properties of bone | Strain Stress Modulus of elasticity Anisotropy Viscoelasticity |
| Strain | *the change in length that is associated with tension (pulling) or compression forces (pushing) *unitless entity |
| Stress | *force per area |
| What does Wolf's law state | *bone will adapt to loads *if loading increases -> bone will remodel to resist loading *if loading decreases -> bone will become weaker due to turnover |
| Anisotropy | *material (bone) response depends on force direction *Structure of the bone determines its response to forces in different directions |
| Viscoelasticity | *response to load varies with rate of loading *high speed vs. low speed impacts cause different types of fractures |
| Stress risers | *things that potentiate stress and decrease bone strength *e.g. geometric irregularities **holes, notches, edges of implants *especially prominent under torsional loading |
| What does Wolf’s law state? | *Bone adapts to forces **Increasing forces -> bone becomes bigger **Decreasing forces -> bone becomes smaller |
| what parameters are tested in material properties | *Stress and strain *Modulus of elasticity (slope) *Anisotropy *viscoelasticity |
| what parameters are tested in structural properties | *size and shape *load *deformation *stiffness (slope) |
| How is the neutral axis defined during bending of a structure? | It is the plane at which there is zero force. |
| Where are tension and compression forces the largest during bending of a long bone (in relation to the neutral axis)? | The further away from the neutral axis, the greater the force (and the greater the bone's response, which is to remodel) --always put plate on tensile side-- |
| Why is it important to appreciate the viscoelastic property of a bone? | Viscoelastic properties predict varying response of bone to hi and lo energy forces: faster loading (hi speed forces, a bullet) causes bone to store more energy, which when released, causes more damage to bone and surrounding soft tissue |
| What are the three factors that may influence the moment of inertia of a bone or implant? | *Shape of the implant *Position of the implant **further away from the Neutral axis = greater resistance to bending *Bone remodeling **Distribution of bone around the neutral axis **X-sectional area of the bone |
| What are the 5 steps in fx management? | patient assessment, fx description, fx assessment, fx fixation method/plan, intra/post op fx assessment |
| Always take _______________ views of a fx. | orthogonal |
| What 3 general factors determine the fx assessment? | biological, mechanical and practical factors |
| Name some of the biological and mechanical factors involved in fx assessment. | biological- age, ST damage, closed v open, systemic dz, nutrition status mechanical-communition, bone loss, intrinsic stability, weight, #limbs affected, controlled v excessive activity, early v delayed fx repair |
| What are the 4 As of your intra-and post-op fx assessment? | *alignment *apposition *apparatus *activity |
| What are the 4 fx healing phases | coagulation (hematoma), inflammatory, repair, remodeling |
| What are the 5 impt factors in bone healing? | animal age, location of fx, stability of fx, vascularity, interfragmentary distance |
| How do interfragmentary strains relate to bone formation? | Greater interfragmentary strain, the greater the risk of nonunion. Response varies between nonunion, granulation tissue formation, cartilage formation/endochondral ossification, and primary healing (<2%) |
| How is bone healing related to fx gap? | Fx gap size dictates whether it will heal via primary or secondary healing |
| What complication may occur if vascularity, stability, or distance are unfavorable? | nonunion, delayed union, infected non-union |
| What is the most common technique to stimulate bone healing? | cancellous bone grafts |
| Describe the rad assessment of a fx. | Obtain 2 views, assess quality and posn of rads, assess surrounding ST, perform stress rad if jt instability is suspected, describe the fx |
| what is the open fracture classification system? | A method to assess open fractures suggesting tx options and prognosis. Based SOLELY on the amt of surrounding ST damage. |
| What are 3 impt plat fxns? | *Compression (DCP- compress 2 fx ends together *neutralization- spans fx to removes load on fx; transmits load thru plate instead (not a specfic type) *buttress/bridging- both used to stabilize; buttress at end of long bones, bridging mid-diaphyseal |
| What are 5 impt implant property requirements? | *stiffness(stress shielding) *strength (repeated load resistance) *ductility (contouring the plate to the need for the fx) *corrosion resistance (think about material properties) *biocompatibility (avoid allergies, immune rxns, etc) |
| Why is post-op rad assessment impt? 6 reasons. | 1. fx mvmt 2. bone inactivity 3. bone resorption 4. bone infection 5. loss of allignment or opposition 6. implant loosening |
| Name 2 properties of a cancellous bone graft. | osteoconductive, osteoinductive |
| Which bacterial pathogen is often associated with iatrogenic infxn? | Staphylococcus aureus |
| What are the signs and symptoms of post-op infxn of fx repair? | Acute- pain, swelling, erythema, inc temp, no rad signs, look for disruption/draining Chronic-draining, muscle atrophy, fibrosis, contracture, lameness, rad changes |
| What is a glycocalyx? | *a carbohydrate film that is laid by the bacteria around an implant with the purpose of protecting itself from antibiotics, antibodies and phagycytosis |
| What does the open fx classification desribe? | *just the extent of surrounding soft tissue damage (nothing to do with the type of fx) and what options are good for those circumstances |
| What forces contribute to a butterfly fragment? Where are the compression and tensile forces relative to bending environment. | ??? |
| If you see a fracture that has a gap between the displaced bones, what type of healing will occur? What if you put in a plate? | If you can see the gap then there will be secondary bone healing. If you put a plate in there, you will get <2% interfragmentary strain (hopefully) and get primary bone healing. |
| what is the purpose of tendons? | to distribute power exerted by more proximally located muscles to the carpus/tarsus |
| How are tendons and ligaments commonly injured? | *direct trauma *repetitive strain *single "Bad step" |
| How are tendon and ligament injuries diagnosed? | US |
| What are some results of tendon and ligament injuries | *prolonged disability *failure to restore normal morphology and fxn *loss of use during convalescence *reduced performance *increased risk of reinjury |
| What are the benefits of US in Dx of ligament and tendon injuries | * sensitive and specific * cost effective (no anesthesia) * early detection of lesions * early intervention |
| What are the tendons and ligaments of the equine metacarpus (cannon bone)from superficial to deep? | *superficial digital flexor tendon *deep digital flexor tendon *inferior check ligament *suspensory ligament |
| Histological and chemical characteristics of tendons | *more mature *type I collagen *fewer cells *less GAGs *organized collagen x-linking |
| Histological and chemical characteristics of ligaments | *more immature *Type III collagen *more cells *more GAG's *less organized x-linking *more rapid adaptation? |
| Summarize causes of OA | *primary OA (humans & cats)- wear & tear (chronic use, aging, obesity) and genetics *secondary OA (dogs)- developmental/congenital (elbow, hip dysplaisa, OCD), mechanical (CCL rupture), traumatic (intraarticular fx) |
| Describe basic pathway in OA development | art cart is highly specialized, gets damaged (collagen&aggregans disrupted)water/matrix protein degraded->integrity of art cart lost->matrix breakdown initiates release of products into jt fluid->inflammation->more enzymes released->more degredation->etc |
| List primary sources of OA pain | OA pain is stiff & uncomfortable. Synovium, jt capsule, subchondral bone all have nerve endings, so its the periarticular changes that cause pain. |
| Describe common clinical findings of OA | muscle atrophy, decreased ROM, pain on manipulation, jt effusion, +/-crepitation/grinding |
| Flexor tendon fxn | support during stance phase flexion during swing phase |
| Extensor tendons | advance limb in prep of stance phase |
| Bursa | large bony protuberance low motion of tendon over joint |
| tendon sheaths | high motion joint small bony protuberance retinacula and annular ligaments |
| Ligament fxn | provide link btw bones support load provide stability to joint |
| Pathophys of tendon/ligament injury in athletes | multifactorial cyclical loading, repetitive weakening excercise accelerates degenerative change no CS increased type III collagen and GAGs |
| pathophys of tendon/ligament injury in non-athletes | sudden overloading degeneration (e.g. degenerative suspensory ligament desmitis) CS: pain, heat, swelling, synovial |
| palpation of tendon/ligament injury | heat swelling pain/sensitivity synovial structures palpable |
| definition of OA | Syndrome that affects synovial jt causing pain and dysfxn. Caused by degeneration of articular cartilage and changes in periarticular tissues. |
| Lameness exam with tendon/ligament injury | may be mild and transient, even with moderate injury hard work --> swelling --> quickly abates doesn't mean it's not injured abnormal limb position, happens in more severe injuries |
| What is the diff visually of normal and damaged articular cartilage? | normal- white, smooth, continuous, shiny damaged-rough, can see underlying structures, see proliferation of synovium (synovitis) |
| what are the basic parameters of tendon/ligament US | X-sectional area Echogenicity fiber pattern |
| what does an injured tendon/ligament look like on US | increased x-sectional area decreased echogenicity disruption of normal fiber pattern |
| CS of mild tendon/ligament injury | mild transient lameness +/- heat and sensitivity |
| CS of moderate tendon/ligament injury | heat and swelling increased lameness peritendinous/periligamentous swelling |
| CS of severe tendon/ligament injury | severe swelling heat lameness +/- abnormal limb position joint instability |
| With OA, what is the one radiographic change you will see? | osteophytosis (bone spurs) but if see OA on rads, then means it is endstage OA |
| How does OA affect pt? | art cart is lost, then fxn of jt is lost->secondary periarticular changes which cause pain and dysfxn. |
| response to acute tendon/ligament injury | fiber disruption -> hemorrhage, edema and fibrolysis inflammatory cells -> proteases & collagenases -> further fibrolysis |
| compartment syndrome | pressure from the hemorrhage, edema and fibrolysis of tendon injury --> pressure necrosis of fibers worst case scenario of an acute injury |
| early healing of tendon/ligament (1-6mo) | granulation tissue replaces fibrin clot fibroblasts produce more type III collagen -weaker than type I -fibers not well aligned with longitudinal axis |
| remodeling phase of tendon/ligament healing (>6mo) | type III collagen gradually replaced by type I some Type III persists fibers gradually realign along long axis may take years |
| how long does repair and remodeling of tendon/ligaments take | 9-12mo if there are no setbacks or if it's not a severe injury |
| what do peritendon/ligament calcifications signify | chronic strain injury |
| traumatic injuries involving synovial structures | req aggressive med and or sx tx guarded prognosis |
| what are some differentials for tendon/ligament injury | peritendinous/periligamentous inflammation w/o tendon/ligament injury secondary joint dz +/- fibrosis of joint capsule tumoral calcinosis calcinosis circumscripta neoplasia |
| goals of treating tendon and ligament injuries | decrease inflammation in acute phase maintain tendon length and strength decrease adhesion formation return to previous level of performance without reinjury |
| how do you decrease inflammation in tendon/ligament injury | hydrotherapy standing bandages NSAIDS (1-2wks) Corticosteroids (limit to 1-2 doses) |
| Tendon splitting | decompression of acute core lesion reduces pressure necrosis use only if US evidence of anechoic lesion |
| Superior check ligament desmotomy | transection of the SCL to elongate the superficial digital flexor tendon makes it less susceptible to reinjury |
| Annular ligament desmotomy | (annular ligament may compress the tendon) to tx severe tendinitis in the distal metacarpal region increases patient comfort |
| How does OA cause poor fxn? | *painful, lose fxn *stiff due to fibrosis, osteophytosis, lose smooth mvmt |
| How can you prevent OA? | *stop breeding dogs with dysplasia, OCD, CCL ruptures *dx and tx early |
| What is current OA tx? | 1. set goal with owner for what is expected fxn 2. do conservative measures 3. if conservative measures don't work OR OA has progressed too far already, do salvage sx procedures |
| How do you dx OA? | 1. PE, Hx, Sig, CS, rads 2. r/o more severe dz like neoplasia, septic arthritis, immune-mediated arthropathy (these are scary, don't miss them) |
| OA CS | Stiffness, difficulty getting up, reluctance to exercise, +/- lameness, may present as behavioral changes |
| Sx repair of severed or ruptured tendons/ligaments | debride devitalized portions suture with enough bite to hold, but not to strangle the vascular supply |
| What does acoustic shock wave therapy do? | pressure waves generated outside the body are focused at a specific site and release kinetic energy increase cell permeability stimulate cell division stimulate cytokine production neovascularization at tendon-bone jxn |
| should you completely immobilize a patient recovering from a tendon/ligament injury? | no, it will result in loss of tendon strenght |
| rehab of SA patients with tendon/ligament injuries vs LA patients | SA - passive range of motion exercises LA - controlled exercise program and stall rest |
| what are the benefits of controlled exercise programs for tendon/ligament rehab? | stimulates maturation of granulation tissue encourages longitudinal alignment of fibers decreases adhesion formation (which increase risk of reinjury) |
| what affects the prognosis of a tendon/ligament injury | severity of initial injury and structure affected adherence to controlled exercise program desired use of the animal attitude and behavior of P and O |
| What is osteochondrosis? | A condition of cartilage and bone; a failure of endochondral ossification (remember this is when cartilage is laid first then replaced with bone) |
| What is OCD? | Thickened cartilage where have the cartilage flap |
| Where does osteochondrosis occur? | |
| how do we dx osteochondrosis? | |
| how do we tx osteochondrosis? | |
| how do we prevent it without developing other problems in the breed? | |
| What is the process of osteochondrosis to the point of a jt mouse? | failure of endochondral ossification (bone not replacing cartilage)-> cartilage thickens->get cartilage folds->get cartilage flaps (OCD)->flap free in jt is a jt mouse |
| what things contribute an animal to having developed the dz? | multifactorial- nutrition, genetics(dogs and horses), biomechanical (some interactions playing a role in disrupting blood supply), growth rate (rapidly growing animals), gender (males are more prone to developing osteochondrosis) |
| where does osteochondrosis occur in a pig? | most common- end of femur, humerous also in shoulder, hip, hock "weak leg syndrome" |
| where does osteochondrosis occur in a dog? | -male, large breeds -most common site: shoulder, cranial aspect of humeral head; elbow, stifle, hock |
| where does osteochondrosis occur in a horse? | most serious- shoulder hock, stifle, fetlocks |
| what things contribute an animal to having developed the dz? | multifactorial- nutrition, genetics(dogs and horses), biomechanical (some interactions playing a role in disrupting blood supply), growth rate (rapidly growing animals), gender (males are more prone to developing osteochondrosis) |
| where does osteochondrosis occur in a pig? | most common- end of femur, humerous also in shoulder, hip, hock "weak leg syndrome" |
| where does osteochondrosis occur in a dog? | -male, large breeds -most common site: shoulder, cranial aspect of humeral head; elbow, stifle, hock |
| where does osteochondrosis occur in a horse? | most serious- shoulder hock, stifle, fetlocks |
| What would you use to detect if there is synovitis? | Joint tap- should have nice stringy characteristic; if inflammation, will be watered down. |
| if suspect osteochondrosis, what is the first thing you want to do diagnostically? | radiographs, and always do both side bc often osteochondrosis is bilateral |
| what is the classic site for osteochondrosis in a dog shoulder? | caudal humeral head see a loss of articular cartilage |
| most common site in horse for osteochondrosis? | lateral trochlear ridge of distal femur |
| How do you image art cart? | Rads, double contrast study (to ID flap location, MRI (but hard to do, U/S (esp stifle OCD), arthroscopy (look directly) |
| When, if signs of osteochondrosis, do you radiograph all limbs? | when the fetlock (metacarpal, metatarsal) jts are invovled |
| How do you tx osteochondrosis? | 1. prevent it from happening? 2. if clinical, do sx: arthrotomy (open approach to jt), arthroscopy (smaller incision and visualize with camera), |
| What do you do if you dx osteochondrosis in a young foal/puppy? | If you are seeing early lesions, let them go on to grow. They usually heal as they grow. |
| Prevention for osteochondrosis. | 1. don't breed affected animals, but be careful in horses bc performance and osteochondrosis is related 2. nutrition 3. prevent xs traumatic or heavy exercise in young animals |
| Sx repair of severed or ruptured tendons/ligaments | debride devitalized portions suture with enough bite to hold, but not to strangle the vascular supply |
| What does acoustic shock wave therapy do? | pressure waves generated outside the body are focused at a specific site and release kinetic energy increase cell permeability stimulate cell division stimulate cytokine production neovascularization at tendon-bone jxn |
| should you completely immobilize a patient recovering from a tendon/ligament injury? | no, it will result in loss of tendon strenght |
| rehab of SA patients with tendon/ligament injuries vs LA patients | SA - passive range of motion exercises LA - controlled exercise program and stall rest |
| what are the benefits of controlled exercise programs for tendon/ligament rehab? | stimulates maturation of granulation tissue encourages longitudinal alignment of fibers decreases adhesion formation (which increase risk of reinjury) |
| what affects the prognosis of a tendon/ligament injury | severity of initial injury and structure affected adherence to controlled exercise program desired use of the animal attitude and behavior of P and O |
Created by:
modonnell