Lameness Flashcards
Which of the following proteoglycans predominates in immature bone in horses? A. Chondroitin sulphate-containing proteoglycans. B. Thrombospondin. C. Decorin. D. Biglycan.
A. Chondroitin sulphate-containing proteoglycans. Proteoglycans form about 10% of the non-collagenous ECM protein. Most of the proteoglycans in immature bone are large chondroitin sulphate containing proteoglycans, as in cartilage, but as the bone matures these are replaced with the small proteoglycans, decorin and biglycan. Ref: Equine Sports Medicine and Surgery, 2nd Edn, Hinchcliff, Geor and Kaneps, 2014.
Collagens and proteoglycans are the two main constituents of the extracellular matrix of cartilage. These two substances have very different turnover times. What is the turnover time of collagen in mature cartilage? A. 300 days. B. 20 years. C. 25 days. D. 350 years.
D. 350 years. Ref: Equine Sports Medicine and Surgery, 2nd Edn, Hinchcliff, Geor and Kaneps, 2014.
Tendons with different functional requirements differ in their mechanical properties as a result of differences in composition. How do the molecular composition of the mature equine superficial digital flexor tendon (SDFT) and the mature common digital extensor tendon (CDET) differ? A. The SDFT has higher water content, higher glycosaminoglycan content and higher cellularity. B. The CDET has higher water content, higher glycosaminoglycan content and higher cellularity. C. The main crosslink in the SDFT is histidinohydroxymesodesmosine (HHMD). D. The main crosslink in the CDET is hydroxylysylpyridinoline (HP).
A. The SDFT has higher water content, higher glycosaminoglycan content and higher cellularity. Ref: Equine Sports Medicine and Surgery, 2nd Edn, Hinchcliff, Geor and Kaneps, 2014.
The digital flexor tendons of the horse are contained within synovial sheaths in regions where they pass over high motion joints. This is a mechanism which is designed to protect the tendons from shear damage, however may also limit the ability of the tendon to heal as paratenon is absent within the confines of the synovial sheath. Why is the paratenon believed to be important in tendon healing? A. This thick surrounding layer of extra-synovial tendon provides a scaffold which maintains structural integrity of the tendon and limits movement during healing. B. The paratenon is highly vascularised and facilitates blood supply to injured tendon regions. C. The paratenon is an important source of fibroblasts capable of repairing injured tendon regions. D. The paratenon provides a physical barrier which limits fluids transposition into the injured tendon and further disruption of tendon fibres as they attempt to re-organise and heal.
C. The paratenon is an important source of fibroblasts capable of repairing injured tendon regions. Ref: Equine Sports Medicine and Surgery, 2nd Edn, Hinchcliff, Geor and Kaneps, 2014.
Which of the following materials has the lowest shock reduction ability when placed on horse feet? A. Aluminium. B. Steel. C. Visco-elastic pads. D. High density rubber pads.
B. Steel. Compared to the reference steel shoe, shock reduction was higher for light shoes made of a polymer and/or aluminium alloy which had lower stiffness values and density than steel. The use of visco-elastic pads contributed to shock reduction and attenuated the high frequency vibrations up to 75%. Ref: Equine Sports Medicine and Surgery, 2nd Edn, Hinchcliff, Geor and Kaneps, 2014.
Which of the following biomechanic factors is important for producing an extended trot in dressage horses? A. Having an inclined scapula i.e. a steeper angle to the scapula. B. Storage of elastic strain energy in the fetlock and hock. C. Storage of elastic strain energy in the pelvis and stifle. D. Positive diagonal advanced placement of the feet i.e. each hindlimb contacts the ground before the diagonal forelimb in the trot.
A. Having an inclined scapula i.e. a steeper angle to the scapula. B, C and D are all features of collected trot. Ref: Equine Sports Medicine and Surgery, 2nd Edn, Hinchcliff, Geor and Kaneps, 2014.
Which of the following is an anti-inflammatory action of exogenous hyaluronte in horses? A. Promotion of granulocyte and macrophage phagocytosis. B. Promotion of macrophage and granulocyte chemotaxis. C. Binding to the HA binding domain of the proteoglycan molecule at the chondrocyte cell surface to supress IL-1β and TNF-α-induced proteoglycan degradation. D. Interaction with the CD40 cell receptor of neutrophils inhibiting neutrophil-mediated degradation and PGE2 production.
C. Binding to the HA binding doman of the proteoglycan molecule at the chondrocyte cell surface to supress IL-1β and TNF-α-induced proteoglycan degradation. HA inhibits granulocyte and macrophage phagocytosis and chemotaxis. D is incorrect as it is the CD44 receptor. Ref: Equine Sports Medicine and Surgery, 2nd Edn, Hinchcliff, Geor and Kaneps, 2014.
Ground surface is influential in fracture development in horses. Select the option below in which the type of ground surface and the most common type of fracture that occurs on Thoroughbred horses racing on that surface are correctly paired. A. Sand; lateral condylar fractures of the third metacarpal bone. B. All-weather surface; proximal phalanx fractures. C. Turf; medial condylar fractures of the third metacarpal bone. D. Dirt; bi-axial proximal sesamoid bone fractures.
D. Dirt; bi-axial proximal sesamoid bone fractures. On all-weather and dirt tracks, bi-axial proximal sesamoid bone fractures are most common, whereas in horses jumping on turf tracks, lateral condylar fractures of the third metacarpal bone are most common, and in flat turf races, proximal phalanx fractures are most common. Ref: Equine Sports Medicine and Surgery, 2nd Edn, Hinchcliff, Geor and Kaneps, 2014.
The above 8 year old Quarter horse mare presents to you for evaluation of a right hindlimb lameness. Her owners report that they have been away for five days and got home this morning to find her toe-touching lame in the paddock. You palpate the limb and detect heat, pain and swelling from the mid cannon to the coronary band. You suspect cellulitis, however are also concerned about potential fetlock effusion and fetlock sepsis. You discuss the risks of performing arthrocentesis through cellulitic tissue with the owners as well as the risks of failure to diagnose joint sepsis in a timely manner, and with reference to the in vitro study performed by Smyth et al, 2015 you tell them:
A. Only large-gauge needles are capable of carrying sufficient S. aureus form cellulitic tissue into a joint to cause joint sepsis, so you will now take a sample of joint fluid from the fetlock using a 19-gauge needle.
B. The risk of sepsis is negligible when performing arthrocentesis through cellulitic tissue, so it is safer to perform arthrocentesis today to rule out or confirm joint sepsis than leave it a few days until the swelling in the leg has gone down.
C. Sepsis can occur from iatrogenic joint contamination when performing arthrocentesis through cellulitic tissue, however this risk is minimal when aseptic preparation of the skin surface and a small-gauge needle are used, therefore you will now clip and perform an aseptic preparation of the skin and take a sample of joint fluid from the fetlock using a 22-gauge needle.
D. Although the bacterial load varies with needle size, needles of 19-22-gauge diameter are all capable of translocating sufficient S. aureus to the joint to cause sepsis when passed through cellulitic tissue, therefore you will not tap the joint today, but will instead institute medical therapy for cellulitis and will re-consider tapping the fetlock joint at a later time based on the horse’s response to therapy.
D. Although the bacterial load varies with needle size, needles of 19-22-gauge diameter are all capable of translocating sufficient S. aureus to the joint to cause sepsis when passed through cellulitic tissue, therefore you will not tap the joint today, but will instead institute medical therapy for cellulitis and will re-consider tapping the fetlock joint at a later time based on the horse’s response to therapy.
Ref: Smyth et al, Am J Vet Res, 2015; 76:877-881.
You attend a sale of 2-year old Thoroughbred racehorses in training in California with a client who is interested in buying a particular colt. You look at the repository radiographs for this horse and note the only abnormal lesions present to be patellar osteophytes in the right hindlimb. What do you advise your client is the significance of this lesion in terms of future performance, according to the findings of Meagher et al, 2013?
A. This lesion is not associated with poor performance, and in fact was associated with improved performance in terms of lifetime earnings, maximum purse, number of 3-year old starts and number of 3-year old earnings than horses with no lesions.
B. This lesion is associated with fever 3-year old starts than horses with no lesions, however was not associated with any other negative impacts on performance.
C. This lesion was associated with lower lifetime earnings and fewer starts compared to horses with no lesions.
D. Horses with this lesion were less likely to earn >$25,000 lifetime earnings than horses with no lesions.
A. This lesion is not associated with poor performance, and in fact was associated with improved performance in terms of lifetime earnings, maximum purse, number of 3-year old starts and number of 3-year old earnings than horses with no lesions.
Overall, career length, number of starts, and earnings did not differ between horses with and without lesions. However, the presence of proximal phalangeal dorsoproximal articular margin chip fractures was associated with lower lifetime earnings and flattening of the medial femoral condyle was associated with fewer 3-year-old starts. Horses that had a 1-furlong presale workout time <11 seconds were more likely to have lifetime starts, lifetime earnings, maximum purse, 2-year-old earnings, and 3-year-old starts and earnings above the threshold.
Ref: Meagher et al, J Am Vet Med Assoc, 2013;242:969-976.
You are called to evaluate a 4 year old Thoroughbred mare who has pulled up during gallop training and is non-weight bearing lame on the right forelimb. You diagnose a P2 fracture. The horse is extremely valuable and the owner elects surgical repair and post-operative management in your clinic’s intensive care unit. The initial surgery goes well but during the next week the mare develops complications associated with the cast. Luckily, you had discussed all possible complications with the owner prior to surgery and she elected to proceed despite the risks! What had you told her, according to Janicek et al, 2013?
A. Your surgeons will reduce the risk of a complication occurring in this case by using a bandage cast, for which the complication rate is 23%, as opposed to 43% for traditional casts.
B. Your surgeons will reduce the risk of a complication occurring in this case by casting the limb in a flexed position, as the risk of complication is lower with the limb in this position than when the leg is cast in an extended or neutral position.
C. The most common complication in horses wearing casts is increased lameness severity, and this occurs in 45% of cases.
D. Cast complications are common and occur in 49% of horses wearing casts. The majority of these complications occur within 14 days of cast application.
D. Cast complications are common and occur in 49% of horses wearing casts. The majority of these complications occur within 14 days of cast application.
The vast majority of these are cast sores. Risks of complication are higher for traditional casts (52%) than bandage casts (34%). For horses with traditional casts the risk of complication is higher if the limb is cast flexed (71%) than neutral (48%) or extended (47%).
Ref: Janicek et al, J Am Vet Med Assoc, 242:93-98.
Impingement of the dorsal spinal processes of the thoracic vertebrae (‘kissing spines’) can be a performance limiting lesion in performance horses. Subtotal ostectomy performed under general anaesthesia has shown to be successful in treating this condition. Brink, 2014, reported 23 cases of subtotal ostectomy for treatment of kissing spines in standing, sedated patients. One reported complication following this procedure was development of dystrophic mineralisation dorsal to the resected dorsal spinal processes. What was the clinical significance of this radiographic finding?
A. Not clinically significant.
B. Not clinically significant in 50% of horses but associated back pain in 50% of horses.
C. Not clinically significant in 67% of horses but associated back pain in 33% of horses.
D. Associated with back pain in 100% horses.
C. Not clinically significant in 67% of horses but associated back pain in 33% of horses.
Ref: Brink, P., Vet Surg, 2014; 43:95-98.
The above 10 year old Paso Fino gelding presents to your clinic for evaluation of progressive, bilateral hindlimb lameness. You advise euthanasia on the ground of animal welfare following locomotory exam in which his fetlocks sink to the point of contact with the ground, and ultrasound examination. The owner has frozen semen from before she gelded him and asks you whether or not she should use this semen. What do you tell her?
A. This condition is likely hereditary, therefore it would not be advisable to use the semen as she may breed affected offspring.
B. This condition is not hereditary, it likely occurred secondary to performance-related injuries, therefore she can safely use his semen to breed unaffected offspring.
C. There is a genetic test for this condition, so you can send off blood or hair from the horse and based on those results she can make an informed decision.
D. This condition is hereditary but it is very rare, so the chance of breeding to a mare that carries the gene is very low, and she can probably use the semen without breeding affected offspring.
A. This condition is likely hereditary, therefore it would not be advisable to use the semen as she may breed affected offspring.
This horse has degenerative suspensory ligament desmitis. It is prevalent is specific horse breeds, and in some families of Peruvian pasos the prevalence is as high as 40%. There is not yet a specific genetic test, but a recent paper identified abnormalities in TGFβ-signaling. The genes affected by the pathology indicate that it is associated with a generalized metabolic disturbance, since some of those most markedly altered in DSLD cells (ATF3, MAPK14, ACVRL1 (ALK1), SMAD6, FOS, CREBBP, NFKBIA, and TGFBR2) represent master-regulators in a wide range of cellular metabolic responses. These findings supported an earlier paper in which abnormal proteoglycan accumulation were noted not just in the suspensory ligament, but also in the superficial and deep digital flexor tendons, patellar and nuchal ligaments, cardiovascular system and sclerae.
Ref: Luo et al, PLoS One, 2016; 11:11 and Halper et al, BMC Vet Red 2006; 2:12
Therapeutic ultrasound is becoming increasingly popular in veterinary medicine. Therapeutic effects are classified as thermal and non-thermal. According to Montgomery et al, 2013, in which tissue is does application of therapeutic ultrasound at a frequency of 3.3 MHz and intensity of 1.0 W/cm2 for 10 minutes result in achievement of therapeutic temperatures?
A. Epaxial muscles.
B. Gluteal muscles.
C. Suspensory ligament.
D. Deep digital flexor tendon.
D. Deep digital flexor tendon.
Mean temperature rise was 3.5°C in the SDFT and 2.5°C in the DDFT at the end of the 1.0 W/cm2 treatment and 5.2°C in the SDFT and 3.0°C in the DDFT at the end of the 1.5‐W/cm2 treatment. Mean temperature rise in epaxial musculature was 1.3°C at a depth of 1.0 cm, 0.7°C at 4.0 cm, and 0.7°C at 8 cm.
Ref: Montgomery et al, Vet Surg, 2013; 42:243-249.
Palmar/plantar digital neurectomy (PDN) is frequently performed in horses with chronic foot pain due to a variety of different lesions. According to Gutierrez-Nibeyro et al, 2015, for which of the following clinical conditions is PDN contradicted?
A. Focal radiolucency of the navicular bone.
B. Core lesions of the deep digital flexor tendon.
C. Grade 4 ossification of the ungular cartilages.
D. Chronic fractures of the palmar or plantar process of the distal phalynx.
B. Core lesions of the deep digital flexor tendon.
PDN can improve or resolve lameness in horses with foot pain unresponsive to medical therapy without serious post operative complications. However, horses with core or linear lesions of the DDFT should not be subjected to PDN as these horses experience residual lameness or early recurrent lameness after surgery.
Ref: Gutierrez-Nibeyro et al, Equine Vet J, 2015; 47:160-164.
The above horse presents to your clinic with anterior enteritis and clinical evidence of a systemic inflammatory response syndrome and laminitis. You wish to perform cryotherapy to reduce the risk of progression of laminitis in this case but find that all bags and boots which you normally use for this purpose do not fit around the feet of this 920kg patient! You consider multiple contraptions and come up with this solution after reading the paper by van Eps and Orsini, 2016, which proved that hoof wall surface temperature was successfully reduced to the goal range for laminitis prevention (5-10°C) after 8 hours of treatment with:
A. Ice packs wrapped around the coronary band.
B. Ice and water immersion with the foot in a 5L fluid bag to at least the level of the pastern.
C. Ice packs wrapped around the distal limb from mid cannon to coronary band.
D. Ice packs wrapped around the distal limb and incorporating the foot.
B. Ice and water immersion with the foot in a 5L fluid bag to at least the level of the pastern.
Seven methods of cooling were compared. The median (range) HWST lowest for the ice and water immersion methods that included the foot and extended proximally to at least include the pastern: 5.2°C for the fluid bag and 2.7°C for the ice boot. An ice boot that included the distal limb but not the foot resulted in a median HWST of 25.7°C. Dry interface applications (ice packs) confined to the foot only resulted in a median HWST of 21.5°C for the coronet sleeve and 19.8°C for a commercial ice pack. For the dry interface applications that included the foot and distal limb, the median HWST was much higher for the ice pack device, 19.9°C (18.7–23.1°C), compared with the perfused cuff prototype of 5.4°C (4.2–7°C).
Ref: van Eps and Orsini, Equine Vet J, 2016; 48:120-124.
A farmer sends you this picture of his daughter’s 18 year old Paint show horse. He went out to feed the cows 2 days ago and found her like this. She is eating and drinking pretty well but hasn’t moved from that spot in the paddock at all since he first saw her. Which of the following injuries could have caused the abnormal stance in this horse?
A. Flipping over backwards and striking the dorsal aspect of his rump.
B. A nail penetrating the foot.
C. A stake injury to the proximal medial thigh.
D. A kick to the lateral aspect of the distal femur.
D. A kick to the lateral aspect of the distal femur.
This horse has peroneal nerve paralysis. This branch of the nerve is most vulnerable to injury where it crosses the lateral condyle of the femur and paralysis is usually secondary to kicks or lateral recumbency. In actual fact it had a penetrating injury over the hock which caused an abscess to develop that tracked cranially and caused inflammation of the nerve.
