Lecture 25: Principles of Orthopedic Sx

What are the reasons to perform orthopedic surgery?

1. Stabilize fractured bones

2. Explore, débride, & stabilize injured joints

3. Replace damaged joints

4. Stabilize spinal column injuries

5. Decompress the spinal cord

6. Resect musculoskeletal tumors

7. Repair tendon and ligament injuries

What is bone transplanted from one animal to another of the same species?

allograft

What are apophyseal osteotomies?

procedures to enhance surgical exposure of a joint

What is bone transplanted from one site to another in same animal?

autograft

What is an avulsion fracture?

insertion point of a tendon or ligament is fractured and distracted from rest of the bone

Bridging plates span ________fracture.

comminuted

What is orthopedic wire placed around circumference of bone to compress an oblique fracture?

cerclage wire

What is a fractured bone alignment performed without surgical exposure?

closed reduction

What is a corrective osteotomy?

diaphysis or metaphysis of a bone is cut, realigned and stabilized until union occurs (elective procedures)

What is a positive cranial drawer test? What is it caused by?

abnormal movement of stifle joint elicited during physical exam → caused by tibia sliding cranially in relationship to femur (cranial cruciate ligament deficient stifle)

What is crepitation?

“grating feel” or sound w/ manipulating a fractured bone or arthritic joint

What type of bone union is formed without evidence of callus?

direct

What is endochondral bone formation?

bone formed on cartilaginous precursor

What is external coaptation?

fracture fixation w/ casts or splints

What is external fixation?

fracture fixation in which pins penetrate bone and skin and connected externally

What is a greenstick fracture?

incomplete fracture where portion of cortex is intact

What is hemicerclage wire or interfragmentary wire?

wire placed through predrilled holes in bone

What is the process of restoring fragment & limb alignment by distracting major bone segments (using animal's weight)?

indirect reduction

What is internal fixation?

fracture fixation using internal implants to secure bone

What are intramedullary pins?

implants positioned in the medullary canal of long bones

What is intramembranous bone formation?

direct differentiation of mesenchymal stem cells into osteoblasts, Bone forms without a cartilaginous precursor

What is complete dislocation of a joint?

luxation

What are healed fractures where anatomic bone alignment not achieved or maintained during healing?

malunions

_____________ plates support a reconstructed fracture.

neutralization

What type of fracture requires surgical intervention to create environment conducive to bone healing?

nonunion

What is a pin started at one end of bone, driven to fracture area, then seated at other end of bone?

normograde placement

What is a fracture repair performed after surgical approach to bone?

open (direct) reduction

What is the ortolani maneuver?

manipulation used to subluxate a dysplastic hip

What is an ostectomy?

removal of a segment of bone

What in an inflammatory condition of bone and medullary canal?

osteomyelitis

What is an osteotomy?

procedure where bone is cut into two segments

What is procruvatum?

cranial bowing of a bone

What is a valgus vs varus deformity?

• Valgus deformity - angulation of distal portion of limb laterally

• Varus deformity - angulation of distal portion of limb medially

What are the objectives in treating fractures, nonunions, or bone deformities?

bone union and return to normal function

What are the possible outcomes of improper orthopedic surgical planning?

• implant failure

• delayed healing

• infection

• nonunion

How is a fracture classified?

1. If fracture is closed or open to external environment

2. Degree of damage & displacement of fragments

3. Type of fracture

4. If fracture fragments can be reconstructed to provide load bearing (reducible or nonreducible)

5. Location of fracture

What type of incomplete fracture occurs in immature animals, leaves a portion of the cortex intact, and partially stabilizes bone?

greenstick fracture

What type of fracture occurs when insertion point of tendon or ligament is fractured & distracted from rest of bone and may be nondisplaced or displaced?

avulsion fracture

What type of fracture has a fracture line perpendicular to long axis of bone?

transverse fracture

What is an oblique fracture?

lines run at angle to line perpendicular to long axis of bone

• Short oblique: 45 degrees or less

• Long oblique: >45 degrees to perpendicular to long axis of bone

What type of fracture is similar to long oblique fractures, but wraps around long axis of bone?

spiral fractures

Comminuted fractures have multiple fracture lines and range from:

• 3-piece fractures w/ butterfly fragment (fragment w/ 2 oblique fracture lines resembling butterfly's silhouette)

• To highly comminuted fractures w/ 5 or more pieces

Classify these fractures from left to right.

transverse, oblique, spiral, comminuted reducible, comminuted nonreducible

What is the difference between reducible and nonreducible fractures?

reducible: single fracture line or fractures w/ no more than 2 large fragments

nonreducible: fractures w/ multiple small fragments

What dictates the number of fragments in a fracture and damage to surround soft tissues?

velocity of forces

Open fractures are classified according to:

1. Mechanism of puncture

2. Severity of soft tissue injury

What is a grade I open fracture?

• Small puncture hole located in skin in proximity of fracture caused by bone penetrating to outside

• Typically ~1cm

• Bone may or may not be visible in wound

What grade of open fracture is this?

I

What is a grade II open fracture?

• Variably sized skin wound associated w/ fracture that resulted from external trauma

• More damage to soft tissue w/ grade II than w/ grade I open fractures

• While extent of soft tissue damage varies- fracture is minimally (or not) comminuted

What grade of open fracture is this?

II

What is a grade III open fracture?

• Severe bone fragmentation w/ extensive soft tissue injury (With or w/o skin loss)

• Usually high-velocity comminuted fractures: Gunshot injuries, Shearing type of injuries of distal extremities

What grade of open fracture is this?

III

What are the salter harris classifications of physeal fractures?

• Salter-Harris type I: run through physis

• Salter-Harris type II: run through physis & portion of metaphysis

• Salter-Harris type III: run through physis & epiphysis & generally articular

• Salter-Harris type IV: also articular - running through epiphysis, across physis, & through metaphysis

• Salter-Harris type V: are crushing injuries of physis

• Salter-Harris type VI : describes partial physeal closures from damage to portion of physis - Causing asymmetric physeal closure

What are these two types of salter harris fractures?

IV and V

What is this type of salter harris fracture?

II

What is this type of salter harris fracture?

I

What is this type of salter harris fracture?

III

What type of fracture patterns is the result of bending forces?

transverse

What type of fracture patterns is the result of torsional forces?

spiral

What type of fracture patterns is the result of axial loading forces?

oblique or comminuted, nonreducible if high energy

What type of fracture patterns is the result of bending and axial compresion forces?

comminuted, reducible

What assessment guides the types of implants chosen?

fracture-assessment score that reflects: mechanical factors, biologic factors, and clinical factors

What are the mechanical factors for patient fracture assessment?

Conditions on left (1): nonreducible & multiple limb injury

• Maximum stress on implant system

• Requires careful implant choice & application

Conditions on right (10):

• Less stress to implant system

• Reduced risk of complications

What are the biologic factors for patient fracture assessment?

Patient factors on left do not favor rapid healing:

• Implant system must function for prolonged periods

• old patient, poor health, cortical bone, poor soft tissue envelope, extensive approach, high-velocity injury

Patient factors on right favor rapid healing:

• Implant only needs to function for a short time

• juvenile, excellent health, good soft tissue envelope, cancellous bone, low-velocity injury, closed

What are the clinical factors for patient fracture assessment?

Clinical factors on left require comfortable implant system:

• Requires little postoperative maintenance

• poor client and patient compliance, wimp, high comfort level required

Clinical factors on right use any implant system:

• Regardless of postoperative maintenance

• good client and patient compliance, stoic, comfort level not a consideration

How are FASs scores generally interpreted?

• high = 8-10, moderate = 4-7, low = 1-3

• fractures with high scores heal successfully with few complications

• fractures with lower scores potentially less successful with more complications