Orthopedics Flashcards
Name the four zones of the physis from the epiphysis to the metaphysis
RPH-PO
Reserve zone
Zone of proliferation
Zone of hypertrophy
Zone of provisional ossification
Zone of the physis where most fractures occur
Hypertrophic Zone
Tendons that contribute to the Achilles tendon
Gastrocnemius (major component), superficial digital flexor + common tendon (gracilis, semitendinosis and biceps femoris)
What is the classification system utilized for external skeletal fixators? describe
Type Ia: (Unilateral, uniplanar), composed of a single bar and clamps through which pins are introduced.
Type Ib: (unilateral, biplanar), composed of two bars located on the same side (i.e. frontal plane) with pins penetrating the bone from two different sides (i.e. craniolateral and craniomedial angles)
Type II (bilateral, uniplanar), composed of two bars on opposite sides of the limb. Further subdivided into “maximal” (all full pins) and “minimal” (full and half pins)
Type III (bilateral, biplanar), typically composed of three or more bars with pins protruding into the limb from three or more different planes.
Major factors contributing to fracture nonunions (3)
• Instability: Typically caused by poor technical judgement and/or execution on the part of the surgeon. Examples include the use of external coaptation in distal radial fractures, IM pins without added constraints against rotational and axial forces, ExFix with insufficient stiffness and loose cerclage wire.
• Poor biological environment: fracture location (small muscle envelope), extensiveness of soft tissue damage (high energy trauma) and surgical trauma may affect blood supply and prolong the debridement phase delaying healing.
• Nutrition: Adequate supply of protein, calcium, vitamin C and D are essential for bone healing and must derive from a well-balanced diet. Supplements are rarely indicated except for malnourished patents.
What are the types of a viable fracture nonunions?
• Vascular nonunion: characterized by cartilage and fibrous tissue formation within the fracture line. Radiographically characterized by a lucent line through the fracture observed on sequential radiographs.
• Hypertrophic nonunion: similar to vascular, but characterized by the presence of a prominent non-bridging callus.
Three properties of cancellus bone graft and their basic physiology
• Osteogenic property: synthesis of new bone from donor cells, which include MSC’s, osteoblasts and osteocytes.
• Osteoinductive property: MSC’s from donor site are recruited to produce chondroblasts and osteoblasts which produce new bone through endosteal ossification. The process is mediated by growth factors such as bone morphogenic proteins (BMP) ad platelet-derived growth factor (PDGF).
• Osteoconductive property: implanted scaffold passively allows ingrowth of host capillaries , perivascular tissue and MSC’s.
Describe the three phases of acceptance of a free skin graft
• Imbibition – (first 24-48 hours) thin film of fibrin and plasma separate the graft from recipient site, providing oxygenation and nutrition (although poorly). After 48 hours a fine vascular network begins to form withing the fibrin layer.
• Inosculation – (day 2 to 3 ) capillary buds interface with the deep surface of the dermis and provide more robust oxygenation and nutrition.
• Revascularization – (day 3 to 5 ) new blood vessels either directly invade the graft or anastomose with to open dermal vascular channels, establishing a permanent vascular supply.
Describe the aetiopathogenesis of Renal Secondary Hyperparathyroidism. What and where lesions are typically found?
The condition is known as Renal Secondary Hyperparathyroidism, characterized by elevated parathormone levels (PTH) secondary to Chronic Renal Disease. PTH is naturally degraded and excreted by the kidneys, and its production is limited by calcitriol (negative feedback inhibition). Calcitriol, the active form of vitamin D, is produced by renal tubular cells. The relative deficiency of Calcitriol induced by renal disease leads to persistently high PTH, which increases calcium resorption from bone and leads to osteopenia.
Bones of the skull and mandible are most commonly affected. Severe demineralization leads to softening to the point that the jaw is bendable (“rubber jaw”). Facial deformity, swelling and pain typically develop.
Most common sign of juvenile hip dysplasia
exercise intolerance
Name the five overlapping stages of secondary bone healing
- Inflammation
- Intramembranous ossification
- Soft Callus Formation (chondrogenesis)
- Hard Callus formation (endochondral ossification)
- Bone remodeling
Describe the sequence of events that take place during the Inflammatory phase of secondary bone healing, from the moment of fracture until the beginning of intramembranous ossification (second phase). State the end product of this phase.
- Inflammation: Loss of vascular integrity leads to hemorrhage and reduction of local oxygen tension. Primary hemostasis occurs and platelets release cytokines and growth factors, recruiting macrophages, neutrophils and other inflammatory cells. Fibroblast and platelet growth factors activate progenitor mesenchymal cells within periosteum, muscle and soft tissues. These progenitor cells will differentiate into osteoprogenitor cells, modulate inflammation and provide anabolic factors to encourage bone healing. Secondary hemostasis produces a hematoma composed of fibrin matrix, which provide further degranulating platelets and serves as a scaffold for mesenchymal cell infiltration as well as macrophages, endothelial cells and fibroblasts. The end result of this phase is the production of a provisional cell, growth factor and matrix-rich scaffold along the cortex, medullary cavity and periosteum into adjacent soft tissues. This scaffold is eventually remodeled into granulation tissue to form a reparative granuloma, termed external callus.
Describe the events that take place during the second stage of secondary bone healing (intramembranous ossification). State the end product of this phase.
- Intramembranous ossification: Mimics the process of skeletal development. Progenitor cells from the overlaying periosteum proliferate and differentiate into osteoblasts to start new bone production adjacent to the fracture gap, between the periosteum and cortex (no cartilaginous intermediate). This leads to the formation of an early hard callus, but is insufficient to bridge and stabilize the fracture.
Describe the events that take place during the third stage of secondary bone healing (soft callus formation/chondrogenesis).
- Soft Callus Formation (chondrogenesis): Starts as soon as a robust bed of granulation tissue is formed across the fracture gap (external callus). Granulation tissue transitions to fibrovascular tissue and finally to fibrocartilage containing collagens type I and III over several weeks. The matrix is initially avascular as resembles the proliferative zone of the physis. The persistent tissue hypoxia, presence of growth factors and cell-matrix interaction cause stem cell population to differentiate into chondrocytes. These chondrocytes produce extracellular matrix rich in collagen Type II, aggrecan and other cartilage-specific proteins. The resulting callus is termed “soft callus” and bridges the fracture gap. This callus is fragile, however, and remains insufficient to decrease strain to a level that permits osteoblast survival.
Name the four bone envelopes?
periosteal, endocortical, trabecular and intracortical
Discuss the fifth phase of secondary bone healing, explaining the role of bone multicellular units (BMU) as it pertains to the production of this phase’s final product (name and explain it).
- Bone remodeling: This final phase of bone healing lasts months to years. The abnormally large and misshapen woven bone produced during ostechondral ossification is weaker than primary bone, and therefore gradually replaced by lamellar bone. Resorption occurs withing each of the four bone envelopes (periosteal, endocortical, trabecular and intracortical). Osteoclasts and osteoblasts work together as Bone Multicellular Units (BMU) is a continuous process of activation, resorption, reversal, formation and quiescence. The end result of the formation of Osteon, a structure composed of concentric layers of bone enclosed by a cement line with a central Harversian canal.
Explain the Wolff’s Law and how it relates to mechanotransduction.
Bone remodeling is strongly influenced by Wolff’s Law, which states that bone in a healthy animal will adapt to the loads under which it is placed. This occurs through the process of mechanotransduction. Bone generates a small electrical potential when it deforms, with an electropositive environment on the concave surface (compression) and electronegative environment on the convex side (tension). Electropositivity is associated with an increase in osteoclastic activity, whereas electronegativity induces osteoblastic activity. This justifies the fact the cortical bone under compression (concave surface) typically appears osteopenic on radiographs, while bone under tension (convex side) appears sclerotic.
Define area moment of inertia
A structural property that describes a structure or material’s ability to resist deformation
How is implant compliance calculated (give formula)? Which factor can be changed with the highest degree of influence on the overall compliance of the contract? How does this apply to a juvenile bone fracture?
Compliance = L3 / I x E
L= functional length (distance between the two innermost screws), multiplied to the third power
I= Area Moment of Inertia (a material or structure’s ability to resist deformation)
E= Elastic modulus of the plate material (inherent to the type of material used in the making of the implant)
Changing the distance between screws (functional length) affects compliance the most, and is typically under the surgeon’s control.
In young patients the physes are still developing and continuously elongating. They are composed of an anastomosed network of medullary vasculature and robust periosteal blood supply with periosteum membrane that acts as an external split. The cortices remain thin and exhibit low stiffness and strength, although have high ductility compared to adult bone. Implants typically fail at the screw-bone interface because the implant is to step in comparison to the juvenile bone. This leads to high stress at the screw-bone interface and eventually implant failure. The use of more pliable constructs, term “elastic osteosynthesis”, has been proposed as a means to distribute stress along the entire plate, limiting stress at the screw-bone interface and minimizing the chance of implant failure.
Define “elastic osteosynthesis” and how it applies to juvenile bone fractures
The use of more pliable constructs, term “elastic osteosynthesis”, has been proposed as a means to distribute stress along the entire plate, limiting stress at the screw-bone interface and minimizing the chance of implant failure.
Define interfragmentary strain and how it determines the kinds of tissues that can be supported within a fracture gap
• Interfragmentary strain: The formation of various tissue types during bone healing is directly dependent on the degree of interfragmentary strain. Strain is defined as the effect of loading on a fracture gap. Practically it is calculated by dividing the resulting length of the gap after loading by the original length. Smaller fracture gaps experience greater strain (concentrate strain) than large gaps. Granulation tissue can withstand almost 100% deformation, and is therefore the tissue found it to be formed within fracture gaps undergoing significant strain. As strain is reduced, tissues region collagen can develop and form a soft callus. Specifically, fibrocartilage is capable of accommodating 10 to 15% deformation. Osteoblasts and osteocytes can only survive in a very low strange environment, and bone can only tolerate 2% deformation.
Give three possible approaches to a distal humeral intercondylar fracture (T-Y fracture) And discuss the pros and cons of each
“A variety of surgical approaches can be used to gain access for accurate fracture reduction of the articular surface. A surgical approach by osteotomy of the tuber olecrani72,81 provides good exposure,2,6,21,106 but complications with repair of the olecranon osteotomy can occur in up to 37% of cases.2,6,39,76 Alternatively, tenotomy of the tendon of the triceps brachii muscle can be performed23,100; this may be advantageous in immature animals because it avoids damage to and possible premature closure of the proximal ulnar growth plate. Intracondylar fractures can also be approached via separate lateral and medial approaches.64 Combined medial and lateral approaches enable exposure of the whole distal part of the humeral diaphysis for fractures with supracondylar comminution. The combined approach avoids risk of damage to the proximal ulnar growth plate in immature dogs.”
Excerpt From
Veterinary Surgery: Small Animal Expert Consult
Spencer A. Johnston VMD, DACVS & Karen M. Tobias DVM, MS, DACVS
https://books.apple.com/us/book/veterinary-surgery-small-animal-expert-consult/id1250368401
This material may be protected by copyright.
Classification scheme for Medial Patella Luxation, expected anatomical abnormalities and clinical signs
Grade 1: the patella can be manually luxated during stifle extension but tends to spontaneously reduce itself. Typically asymptomatic incidental finding.
Grade 2: Spontaneous luxation occurs with clinical signs ranging from non-painful “skipping” lameness to mild discomfort. Mild deformities typically exist, consisting of internal tibial rotation and abduction of the hock.
Grade 3: The patella is permanently luxated by can be manually reduced. More severe bony deformities are usually present, including marked internal tibial rotation, distal femur varus and a shallow troclear groove. The patient usually stands with a “crouched” posture due to internal rotation of the stifle.
Grade 4: The patella is luxated and cannot be manually reduced. Similar anatomical abnormalities as for Grade 3, but more severe. The tibia is internally rotated between 60 and 90 degrees relative to the sagittal plane. Severe mobility impairment present, similar to grade 3 but more severe.
Pelvic fractures: how many sites are typically fractured? In order a frequency, where are the fractures most commonly located?
 “Of 556 cases of pelvic fractures in dogs and cats, 76% of cases had fractures at three or more sites. The pubis was the most frequently fractured bone, followed, in order of frequency, by the ischium, sacroiliac joint, ilium, acetabulum, and pubic symphysis.”
Excerpt From
Veterinary Surgery: Small Animal Expert Consult
Spencer A. Johnston VMD, DACVS & Karen M. Tobias DVM, MS, DACVS
https://books.apple.com/us/book/veterinary-surgery-small-animal-expert-consult/id1250368401
This material may be protected by copyright.
How are acetabular fracture‘s classified according to location of involvement of the articular surface? Fractures affecting which areas demand anatomical reconstruction?
“Fractures of the acetabulum are classified as cranial, central, or caudal according to the location of involvement of the articular surface. The cranial and central portions of the acetabulum are the weight-bearing areas, and fractures of these areas should be anatomically reduced and rigidly fixed for optimal function. Caudal fractures are less demanding but may result in degenerative joint disease with conservative treatment.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Approximately what percentage of pelvic fractures will have bilateral iliac body fractures, acetabular fractures or acetabular fracture’s coupled with contralateral iliac body fracture?
“approximately one-fourth of pelvic fractures involve bilateral iliac body fractures, bilateral acetabular fractures, or acetabular fractures coupled with a contralateral iliac body fracture. ”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
What are the three zones of contact in the elbow?
- Caudomedial aspect of the radial head
- Distomedial aspect of the articular surface of the trochlear notch, extending into the radial incisure
- Craniolateral surface of the proximal portion of the trochlear notch
What are the main contraindication for PAUL, CUE and Sliding humeral osteotomy?
OA affecting the lateral compartment for the elbow
Describe a Monteggia fracture
When fracture of the proximal part of the ulna is associated with a radial head luxation, it is referred to as a Monteggia fracture.”
Excerpt From
Veterinary Surgery: Small Animal Expert Consult
Spencer A. Johnston VMD, DACVS & Karen M. Tobias DVM, MS, DACVS
https://books.apple.com/us/book/veterinary-surgery-small-animal-expert-consult/id1250368401
This material may be protected by copyright.
Describe how to perform the Barden test
“With the patient in lateral recumbence, place the thumb and index finger of the upper hand on the greater trochanter. Gently grasp the flexed stifle joint with the lower hand with the thumb on the lateral aspect and the remaining fingers extended on the distal aspect of the femur. Press laterally with the fingers of the lower hand to lever the femoral head out of the acetabulum. Alternately, press down on the greater trochanter to reduce the femoral head back into the acetabulum. A normal hip joint should have little to no subluxation. Juvenile hip dysplasia may result in up to two centimeters of lateral subluxation.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
What are the 4 planning steps in the selection of an appropriate fracture repair?
“The process of selecting an appropriate method of fracture repair includes the following steps:
(1) patient assessment,
(2) fracture assessment,
(3) fracture assessment scoring, and
(4) selection of the fracture repair method.
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
What is the difference between Mechanical and Biological Fracture Assessment as it pertains to fracture scoring?
“Mechanical assessment estimates the strength of implant necessary. Biological assessment estimates the length of time implants must be functional (i.e., time to bone union). ”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Fracture Scoring: Define High, Moderate and Low score fractures. Give examples of type of repairs that can be employed for each case
Low Scores (1 to 3): Generally, these are nonreducible fractures in older animals in which healing will be affected by other extenuating circumstances. Implants must bridge these fractures and therefore must have sufficient strength to prevent permanent bending or breakage for more than 6 weeks. Suggested implants (or combinations of implants) with sufficient strength and stiffness to function at the lower end of the fracture assessment scale are lengthening bone plates (see p. 1022), locking bone plates, bone plate–intramedullary (IM) pin combinations (“plate-rod”) (see p. 1022), interlocking nails (see p. 1011), or type III external fixators (see p. 998). These patients are not candidates for casts, IM pin, and cerclage wire fixation. Bone grafting should be considered in patients with low fracture assessment scores.
Moderate Scores (4 to 7): Overlapping biological and mechanical factors affect healing and implant selection when the fracture assessment score moves toward midscale. For example, in an older dog with a transverse fracture, the implant and bone share the load after surgery, and the implant will be subjected to less stress, but healing may be delayed. Alternatively, in an immature dog with a nonreducible fracture, the biological assessment may indicate early callus formation, despite “the implant being subjected to high initial loads as it functions to bridge the fracture. In both situations, less implant strength and endurance are required than in patients with low assessment scores because of either immediate load sharing or early callus formation. Suggested implants include bone plates, type II external skeletal fixators, IM pin–external skeletal fixator combinations, and interlocking nails. Bone grafting may be considered in patients with moderate fracture assessment scores.
High Scores (8 to 10): When the fracture assessment score is high, mechanical assessment indicates minimal implant stress because of load sharing, and biological assessment indicates enhanced healing potential. Immediate load sharing between the bone-implant construct and rapid bone union are expected. Suggested implants include type I external skeletal fixators, IM pin–cerclage wires, and external coaptation. Bone grafting is rarely indicated in patients with high fracture assessment scores.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Define “positive” and “negative” radio-ulnar incongruence
‘Positive” and “negative” refer to the ulna.
“Positive” radio-ulnar incongruence = ulna too long
“Negative” radio-ulnar incongruence = ulna too short
Describe the caudal approach to the ulna as utilized to repair a Monteggia fracture
“For a caudal approach to the proximal ulna, make an incision through skin and subcutaneous tissue over the caudoproximal ulna. (B) Elevate the flexor carpi ulnaris and the deep digital flexor muscles to expose the bone surface. (C) Reflect the origin of the flexor carpi ulnaris muscle to expose the trochlear notch.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Describe the technique for proximal ulnar osteotomy, including recommended angles
“In the proximal third of the ulna, perform an oblique osteotomy; the angle of the osteotomy should be caudoproximal to craniodistal (Fig. 34.45A) and craniolateral to caudomedial (Fig. 34.45B). Reappose the periosteum with 3-0 absorbable suture in a simple continuous pattern. Close the deep fascia in a simple continuous pattern with absorbable suture. Apply a bandage for 3 to 5 days to aid in patient comfort.”
23 deg on lateral plane and 30 deg on caudal plane (in relation to anatomical axis of the ulna)
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Describe the technique for distal segmental ulnar ostectomy
“Make a 3-cm longitudinal incision over the lateral aspect of the distal third of the ulna, ending at the distal ulnar physis. Dissect between the tendon of the lateral digital extensor muscle and the tendon of the ulnaris lateralis muscle to expose the diaphysis of the ulna. Incise and elevate the periosteum, and isolate the ulna with Hohmann retractors. Remove a 5-mm-length section of the ulna with an osteotome, rongeur, or bone saw. Reappose the periosteum with 3-0 absorbable suture in a simple continuous pattern. Close the deep fascia in a simple continuous pattern with absorbable suture. Apply a soft bandage for 3 to 5 days to aid in patient comfort. Various locations for the distal ulnar osteotomy have been used. Elevation of the interosseous ligament off the ulna aids in distal migration of the ulna; however, it may lead to significant hemorrhage.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Describe the postoperative care for a patient immediately afterward and for the first 8 to 12 weeks after ulnar osteotomy
“Immediate postoperative radiographs should be made. The limb may be bandaged after surgery for up to 1 week to provide soft tissue support, and the animal should be confined for 4 to 8 weeks. Repeat radiographs are recommended 6 weeks after surgery. Physical rehabilitation may be beneficial in management of osteoarthritis and in improving the range of motion (see Table 34.7). After surgery, cryotherapy, passive range of motion, and controlled leash walks are the primary methods of physical rehabilitation.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Surgical treatment of elbow MCD is meant to decrease pain and inflammation by decreasing stimulation of exposed subchondral bone. How can this be accomplished (categories of surgical treatment)
“Surgical treatments of MCD are intended to decrease pain and joint inflammation by decreasing stimulation of nerve endings located in the subchondral bone. This may be accomplished by removal of the coronoid (subtotal coronoidectomy), decreasing transarticular loads (sliding humeral osteotomy [SHO], radial osteotomy, ulnar osteotomy), or replacing the bearing surface (total elbow replacement).”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Breed most commonly affected by idiopathic or immune-mediated carpal joint collapse
“Shetland sheepdogs, are overrepresented for idiopathic or immune-mediated collapse of the carpal joints.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Describe the 3 categories of carpal hyperextension injuries
Category I injuries are subluxations or luxations of the antebrachial carpal joint.
Category II injuries include subluxation of the middle carpal and carpometacarpal joints and are associated with disruption of the accessory carpal ligaments, palmar fibrocartilage, and palmar ligaments of the middle carpal and carpometacarpal joints. Dorsal displacement of the free end of the accessory carpal and ulnar carpal bones occurs.
Category III injuries are disruptions of the accessory carpal ligaments, carpometacarpal ligaments, and palmar fibrocartilage. However, in these injuries subluxation of the carpometacarpal joint occurs without disruption and displacement of the accessory carpal and ulnar carpal bones.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
What are the two most common causes for progressive collapse of the carpal joints?
“Differential diagnoses for progressive collapse of the carpal joints include any form of polyarthritis or joint collapse due to chronic steroid administration.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Discuss the anatomy of the carpus. Include names of bones, articulations, anatomical divisions (joints) and important ligaments. Discuss the importance of the accessory carpal bone.
“The carpus consists of seven bones arranged in two rows. The radiocarpal and ulnar carpal bones make up the proximal row, and the first, second, third, and fourth carpal bones make up the distal row. The accessory carpal bone lies caudally and articulates with the ulnar carpal bone. The radiocarpal and ulnar carpal bones articulate with the radius and styloid process of the ulna to form the antebrachial carpal joint. The middle carpal joint, formed by articulation of the proximal and distal rows of carpal bones, has the greatest movement—accounting for 10% to 15% of carpal motion. Very little motion occurs in the carpometacarpal and intercarpal joints. Palmar support is from the flexor retinaculum proximally and palmar fibrocartilage distally. Multiple small ligaments cross the intercarpal articulations between carpal bones to provide additional collateral and palmar support. Two accessory ligaments originate from the free end of the accessory carpal bone and insert onto the palmar surface of the fourth and fifth metacarpal bones. The caudal position of the free end of the accessory carpal bone, in conjunction with the accessory carpal ligaments, acts as a moment arm to balance the vertical force produced when the paw strikes the ground.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
List three possible options for the stabilization of a stifle with a CAUDAL cruciate ligament rupture
“Joints with caudal cruciate ligament injury are treated with resection of the remnants of the ligament and stabilized by one of several extracapsular reconstruction techniques: suture stabilization, redirection of the medial collateral ligament, or popliteal tendon tenodesis. Suture stabilization consists of imbrication of the caudomedial joint capsule and placement of a medial or lateral stabilizing suture. Redirection repair uses existing autogenous tissue, such as the medial collateral ligament.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Describe the function of the stifle collateral ligaments and their status (tension/relaxation) during the different phases of the gait
“The medial and lateral collateral ligaments function in concert to limit varus-valgus motion of the stifle joint. This is most important when the stifle joint is extended and both the medial and lateral collateral ligaments are taut. As the stifle joint flexes, the medial collateral ligament remains tight, but the lateral collateral ligament relaxes to allow internal tibial rotation. This motion permits the foot to turn inward beneath the body during ambulation. As the stifle joint extends, the lateral collateral ligament becomes taut once again to assist in external rotation of the tibia. This motion aligns the foot into proper position for weight bearing.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
In what position should the stifle be held when evaluating the integrity of the medial and lateral collateral ligaments?
“Be sure to hold the stifle joint in extension when assessing the medial and lateral restraints.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Describe how you would repair a midsubstance medial collateral ligament rupture
“If the ligament injury is an intrasubstance tear, perform primary repair by suturing the ligament ends; use a locking-loop suture pattern with small, nonabsorbable suture (see p. 1283). Supplement the primary repair with screws or bone anchors and figure-eight support (Fig. 34.134C). After repair of the collateral ligament, carefully reconstruct the meniscocapsular ligaments and joint capsule using interrupted sutures of small, nonabsorbable suture material (polypropylene or nylon).”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Describe the possible relationship between hit luxation/FHO and patellar luxation
“Careful examination of the hip joint is essential because some patients with patellar luxation also have avascular necrosis of the femoral head (see p. 1255) or hip dysplasia (see p. 1209). Shortening of the limb because of hip luxation (see p. 1220) or FHO (see p. 1213) will cause laxity of the quadriceps mechanism, enabling luxation of the patella in some cases. This usually resolves with treatment of the hip luxation and with time after FHO.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
When is surgical correction of a patellar luxation indicated?
“Surgery is advised in symptomatic immature or young adult patients because intermittent patellar luxation may prematurely wear the articular cartilage of the patella.73–75 Surgery is indicated at any age in patients showing lameness and is strongly advised in those with active growth plates because skeletal deformity may worsen rapidly. The surgical techniques used in actively growing animals should not adversely affect skeletal growth. Owners of dogs with bilateral grade IV patellar luxations should be warned of the likely need for multiple surgeries and probable continued lameness even after successful surgery because of the severity of the underlying long bone abnormalities.74”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
What is the primary causative abnormality of patellar luxation? Why does it matter from a surgical point of view?
“It is important to understand that the primary abnormality is biomechanical, whereby the patella within the straight quadriceps mechanism fails to align with the trochlear groove. Surgeries that involve only deepening of the trochlear groove, capsule and fascial release, and imbrication are more prone to failure, as the patella and trochlear groove have not been permanently realigned.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Where is Stifle OCD most commonly observed?
“With OCD of the stifle, a piece of cartilage and subchondral bone is usually observed that involves the medial surface of the lateral femoral condyle (most frequently affected) or the medial femoral condyle. The condition is often bilateral.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Typical signalment for patients affected by Legg-Perthes disease
“Legg-Perthes disease is diagnosed in young, small-breed dogs (i.e., <10 kg). The peak incidence of onset is 6 to 7 months with a range of 3 to 13 months, and males and females are equally affected. This condition occurs bilaterally in 10% to 20% of affected animals.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Legg-Perthes disease results in collapse of the femoral epiphysis due to interruption of blood flow. Explain the pathophysiology of this process
“The vascular supply to the femoral head in young animals with open proximal femoral physes is derived solely from epiphyseal vessels; metaphyseal vessels do not cross the physis to contribute to femoral head vascularity. Epiphyseal vessels course extraosseously along the surface of the femoral neck, cross the growth plate, and penetrate bone to supply nourishment to the femoral epiphysis. Synovitis or sustained abnormal limb position may increase intraarticular pressure enough to collapse the fragile veins and inhibit blood flow. An autosomal recessive gene has been proposed as a genetic cause for the development of aseptic necrosis of the femoral head. After cell death occurs, the reparative processes begin. The bone substance is weakened mechanically during the revascularization period, and normal physiologic weight-bearing forces may cause collapse and fragmentation of the femoral epiphysis. When this happens, incongruence of the femoral epiphysis and acetabulum results in DJD. Fragmentation (fractures) of the femoral epiphysis and osteoarthrosis cause pain and resulting lameness.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
When should the capital femoral physis close? From which physis does the femur derive most of its growth?
“The capital physis functions to provide femoral neck length until the animal is approximately 8 months of age. The distal physis functions to provide most of the femoral length.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Typical signalment for a patient dog or a cat) with a femoral capital physeal fracture?
“Most affected animals are younger than 10 months. Young male dogs are more likely to sustain trauma resulting in femoral physeal fracture, probably because of their tendency to roam. Young heavy male cats that have been neutered before 6 months of age are also at risk.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Describe the surgical treatment of femoral capital physeal fractures (repair type, implants)
“Surgical treatment of physeal fractures consists of anatomic reduction and stabilization with K-wires or small pins that are smooth so as to not interfere with any residual physeal function. These fractures heal rapidly, and smooth implants are generally sufficient. In animals that are close to maturity, threaded implants may be used to increase the stability of the fixation. Anatomic reduction is critical for optimal outcome with capital physeal fractures. Mechanically, prevention of movement of the reduced capital physeal and distal physeal fractures is assisted by the shape of the fractured physeal surfaces. If separated, the physis of the greater trochanter must also be anatomically reduced and stabilized with a tension band to counteract the distractive forces of the gluteal muscles.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
What are the main differences on the approach to treatment of patellar fractures between dogs and cats?
“Conservative management is indicated in cats if minimal displacement of the patellar segments occurs. Conservative management (i.e., rest or passive physical therapy) is not indicated in dogs if a transverse or comminuted fracture has separated the proximal and distal poles of the patella. Fibrous union may occur, but the stability afforded is insufficient to allow normal activity. Small fragments near the proximal or distal pole may be managed conservatively if they do not interfere with motion of the patellofemoral joint.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
What is the prognosis and complication rate for feline patellar fractures treated surgically?
“Feline patellar fractures treated with pin and tension band fixation have a high complication rate, with greater than 85% of cases resulting in additional fracture and fragment displacement. Transverse proximal tibial fractures may occur in cats with chronic nonunion of transverse patellar fractures.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
What is the prognosis for surgically-treated patellar fractures in dogs
“Return to athletic function in dogs depends on adequate healing and reduction of the articular surface. Radiographic evidence of degenerative joint disease will usually develop. Functional prognosis is good to excellent if postoperative instructions are followed closely and if the integrity of the patellofemoral joint is maintained. ”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
What is the prognosis for patellar fractures managed conservatively in cats?
“Most cats with patellar fractures progress to a fibrous or functional nonunion, with many cats exhibiting intermittent lameness. Osteoarthritis and peripatellar ossification are commonly seen in cases given long-term follow-up.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
What are two of the most common chronic muscle strains observed in dogs? (Although both are relatively rare)
“Chronic muscle strains (e.g., bicipital tenosynovitis, iliopsoas muscle injury) occasionally occur in dogs.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
What are the definitions of muscle “contusion” and “strain”?
A contusion is a bruise of the muscle with varying degrees of hemorrhage and fiber disruption.
A strain is a longitudinal stretching or tearing of muscle fibers or groups of fibers.
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Lameness exacerbated by exercise. Hyperextension of one digit. Where is the lesion?
“Dogs with chronic tendon lacerations have lameness exacerbated by exercise. Those with isolated deep digital flexor tendon lacerations have characteristic hyperextension of one digit.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Describe the appropriate surgical repair of a muscle laceration
“Thoroughly debride the wound edges to fresh, bleeding muscle (Fig. 35.3). Debride carefully to prevent excess removal of tissue, which makes apposition of the severed ends difficult. Place interrupted sutures in the outer muscle sheath around the circumference of the muscle. Support the appositional sutures with heavy stent sutures placed in a cruciate pattern.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
What suture material (material properties) would you look for when selecting Sutures for the repair of a muscle laceration versus a tendon laceration?
“Nonabsorbable or absorbable suture material may be used to repair muscle, provided the material maintains its mechanical strength for 3 to 4 weeks. Nonabsorbable suture material is recommended for tendon repair. Swaged-on needles are helpful in limiting tissue trauma during suturing.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
What is the recommended postop activity restriction after the repair of a muscle laceration?
“After muscle repair, the limb should be immobilized for 5 days, followed by 4 to 6 weeks of protected activity. ”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
What is the recommended activity/load restriction after the surgical repair of a major Tendon?
“After tendon repair, the limb should be immobilized for 3 weeks with the use of rigid external coaptation, protective orthotics, or external fixation with the joint positioned to release stress on the repaired tendon (see p. 981). When the splint is removed, the limb should be semirigidly immobilized for an additional 3 weeks with a heavy padded bandage or a half cast (i.e., one side of a split cast applied cranially or caudally to the limb). ”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Breed affected by bilateral idiopathic Achilles tendon degeneration
“Doberman pinschers may have idiopathic bilateral common calcanean tendon degeneration.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Describe the medical management for complete and for partial common calcaneal tendon ruptures. What is the success rate?
Trick question :)
“Surgical repair of completely ruptured tendons is indicated; medical management is not. External coaptation may be tried with partial rupture, but results are usually unsatisfactory.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Describe the surgical repair of acute and chronic Achilles tendon ruptures
“Make an incision over the site of injury on the caudolateral surface of the limb. If the injury is acute, identify the three tendons composing the Achilles complex, and suture each tendon separately with an interrupted far-near, near-far pattern (see Fig. 35.4) using nonabsorbable, small-diameter (3-0 to 4-0, depending on the size of the animal) monofilament suture. If the injury is chronic and identification of individual tendon units is not possible; continue surgical dissection to expose the circumference of the thickened fibrous band. Then sequentially remove sections of scar tissue from the center of the mass. Remove enough tissue so that tension is present in the Achilles complex when the stifle joint is in a normal standing position and the tarsus is slightly extended. Be careful to avoid removing too much of the proliferative fibrous tissue. If excess fibrous tissue is excised, apposition of the cut ends will be difficult. Suture the cut ends with a three-loop pulley pattern (see Fig. 35.4).”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
What diagnostic and therapeutic option is recommended for all cases of presumed supraspinatus or biceptal tenosynovitis? Why?
“Disease of the biceps and the supraspinatus may occur together, and thickening of the supraspinatus may displace the biceps tendon, resulting in inflammation and pain.2 In the most severe cases, other diseases of the shoulder (e.g., instability, osteoarthritis) may also be identified; thus shoulder arthroscopy should be performed in dogs with suspected supraspinatus tendinopathy. Radiographic mineralization is a common incidental finding and is not associated with clinical lameness; therefore accurate determination of the cause of the lameness is critical.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
What is the most common ultrasound finding in patients with supraspinatus tendinopathy?
“The most common ultrasound finding in dogs with supraspinatus tendinopathy is enlargement of the tendon of insertion”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
You are presented with a middle-age large breed dog with a history of recurring exercise induced forelimb lameness. On radiographs observe mineralization of the supraspinatus muscle tendon insertion. You suspect supraspinatus tenosynovitis. List 4 other possible differential diagnosis.
“Mineralization of the supraspinatus tendon must be differentiated from other shoulder diseases, including biceps tendinopathies. Differential diagnoses include biceps tenosynovitis, osteochondritis dissecans, shoulder instability, and shoulder osteoarthritis.”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
Describe the medical management of supraspinatus or bicipital tenosynovitis. What are the risks of corticosteroid injections? What are their injectable therapies can be considered? Physical Therapy options? Benefits?
“Medical management of supraspinatus mineralization is often attempted first. Glucocorticoid injections combined with rest are often attempted and may provide temporary relief. Injection of glucocorticoids into the tendon may cause tendon degeneration; therefore multiple injections are not recommended. The use of PRP in the treatment of supraspinatus tendinopathy is currently being investigated (see Chapter 31).”
“Physical rehabilitation for mineralization includes cryotherapy and passive range of motion. Therapeutic ultrasound may aid in eliminating mineral deposits in the muscle (see Chapter 11).”
Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.
You are presented with a 10 month-old pug with a history of progressive left hind limb lameness. These are his radiographs. What is your diagnosis?
Legg-Calve-Perthes disease
Define Plate Screw Density (PSD)
Plate screw density is the quotient formed by the number of screws inserted and number of the plate holes (From Gautier E, Sommer C: Injury 34(Suppl 2), 2003).
Young cat presented with retained deciduous teeth and stifle pain. Name the condition.
Feline knees and teeth syndrome
