Chapter 102 - Femur and pelvis Flashcards
Postoperative radiographic view of the femoral head region of a foal. Three 4.5-mm cortex screws were inserted in lag fashion into the capital femoral epiphysis. The trochanteric osteotomy used for the surgical approach to the joint was repaired with screws and tension band wires. There also was a radiolucent tension band placed under one washer.
What types of horses are primarily affected by disorders of the femur and pelvis?
A. Only young horses
B. Only racehorses
C. Horses of any age, breed, or activity
D. Only older horses
C. Horses of any age, breed, or activity
What are the most common surgically treatable conditions of the femur and pelvis?
A. Arthritis and ligamentous injuries
B. Fractures or coxofemoral luxations
C. Muscle tears and tendonitis
D. Joint dislocations
B. Fractures or coxofemoral luxations
In which age group do proximal (head and neck) femur fractures most commonly occur?
A. Foals and weanlings
B. Adult horses
C. Elderly horses
D. Yearlings
A. Foals and weanlings
What is a common cause of proximal femoral fractures in adult horses?
Severe traumatic events
What is usually palpable with manipulation in cases of distal or diaphyseal femur fractures?
Crepitus
How are diagnostic radiographs usually performed in larger horses?
Under general anesthesia
What is the prognosis for surgical treatment of proximal femoral fractures in foals?
Good
What are the techniques for surgical resolution of proximal (head+neck) fractures?
Techniques:
1.Screws inlag fashion
2.Cannulated screws
3.Dynamic hip screwplate (DHS chapter 72)
What is the favored surgical approach for proximal (head and neck) fractures?
Craniodorsal
What technique is used to enhance exposure during surgery for proximal femoral fractures?
A. Tenotomy of the middle or deep gluteal muscle
-Expose the femur by doing tenotomy of the tendon of the middleglutealmuscle atthe caudal greater trochanter (GT)
-OR tenotomy of the tendon of the deepglutealmuscle atthe cranial great trochanter (GT)
Describe the surgery after tenotomy performed
-Osteomy of GT selected?
Drill holes for later tension-band repairshould be prepared before transecting the bone
-Oscillatingsaw or Gigli wireto cut GT from disto lateral to proximo-medial position
What does the trochanteric osteotomy allow to move?
Trochanteric osteotomy allows middle gluetal muscle to be retracted proximally andmedially exposing theproximal aspect of the fémur and femoral head
What is the prognosis of proximal head+neck fractures?
Guarded
What can happen if you cut too deep the trochanteric osteotomy?
Damage the femoral head
How should you prepare the great trochanter for placement of screws after and washers?
5.5 mm screwslag fashion
* Glide hole is drilled before reduction
- allow to check central position before entering ephiphysis withthread hole
* Combo of miminal lenght glide hole + central position of the bit = maximize the number ofthreads engaged in smallerfragment
- Washer s recommended
- screw 5.5 mm do not sink in soft cortical bone
Alignement is critical to prevent damage of articular surface
What is the nerve that lies immediately caudal to the acetabulum and cannot be mobilized?
sciatic nerve
How do you insert the screws following the GT removal?
3.2 mm drill bit to drill the thread hole through the lateralfemur upthe femoral neck and into the center of the femoral metaphysis.
Fracture is then reduced and the epiphysis drilled.
To prevent penetration of the articularsurface finger is placed in expected exit.
Drilling and tapping this initial hole while maintaining fracture reductionare difficult.
Loss of reduction makes it difficult toreposition and relocatethe 3.2 mm hole.
Leaving the initial drill bit in place tomaintain reduction à while drilling + inserting a second cancellous screw= is the most effective method forestablishing fixation without losing the reduction.
The guidepins in the 7.3 mm cannulated screw system achieve the same temporary fixation. Prior to tapping the hole, a depth gauge is used to determine the appropriate‐length screw and a 4.0 mm drill bit is used to expand and form a glidehole in the cortical bone of the lateral cortex. It is not necessary to enlarge this holethrough the entire metaphysis.
The cancellous tap will not easily pass through the lateral cortex, but will readily penetrate the metaphyseal bonealong the path ofthe 3.2mm drill.
The hole depth is determined from the millimeter gradations on the tap,allowing the surgeon toanticipate when the articularsurface is being approached, as well as to confirm the length of screw thatwill be necessary.
The cancellous tap is used to tap thehole within the epiphysis until it nears the surface of thearticular cartilage.
Insert 2 or 3 of 6.5mm cancellous screw
apply suction drain deep within the site
What is the advantage of cannulated screws?
the reduction is maintained by the guide wire during entire procedure and you see depth
Disadvantage: bend easily
Which fractures are considered the most difficult femoral fractures to diagnose without radiographs?
Proximal (head and neck) fractures
Which implant provides more stability in femoral fracture repair according to the text?
Double plating
What is the primary location for third trochanter fractures?
Lateral aspect of the proximal third of the femur
What is a proposed mechanism of injury for third trochanter fractures?
Avulsion
What is the initial degree of lameness observed in horses with third trochanter fractures?
Moderate to severe
What diagnostic tool is often best for identifying third trochanter fractures?
Nuclear scintigraphy
What is the commonly elected management for third trochanter
fractures in horses?
Conservative management with fibrous union
How long is exercise restriction typically advised for horses with third trochanter fractures?
1 month of stall rest followed by 1-2 months of hand walking
What is the prognosis for return to soundness after a third trochanter fracture?
Fair to good
Which muscle serves as an insertion for the third trochanter at the apex?
Gluteus superficialis
What is the main symptom in the acute phase of a third trochanter fracture?
Mild swelling over the fracture region
What is the most common type of fracture encountered in the femur?
Middiaphyseal fractures
What is the typical shape of middiaphyseal fractures?
Spiral or long oblique
Where is the skin incision typically made for surgery on middiaphyseal fractures?
Laterally over the bone
What anatomical landmarks are identified after the fascia lata is incised during surgery?
Vastus lateralis and biceps femoris muscles
In the case of severe comminution, what method is used to reduce small fragments?
3.5-mm cortex screws in lag fashion
What is often used to prevent splitting the bone during reconstruction of a barrel stave fracture?
Cerclage wires or cables
Lateromedial radiographic view of a multifragment femoral fracture in a foal.
Lateromedial radiographic view of a multifragment femoral fracture in a foal.(C) and(D) Immediate postoperative radiographic views depicting the fracture repaired with two DCPs, one laterally and one cranially. Several fully threaded cancellous screws were used in the metaphyses. The arrow points toward the proximal end of the suction drain.
(E) Three-month follow-up radiographic view showing good fracture healing with substantial callus formation. A small fragment is visible at the cranial aspect of the bone.
How is the fracture usually reconstructed before reduction barrel stave fracture?
Into two main pieces
What technique is often used to maintain reduction during the progression of surgery barrel stave fracture?
Use of nylon cable ties or heavy cerclage wires
What types of plates are typically used for the repair of these fractures barrel stave fracture?
4.5- or 5.5-mm locking compression plates
How is the incision closed after surgery?
In at least three layers
What is an alternative technique mentioned for simple diaphyseal fractures?
Insertion of an interlocking intramedullary nail
What does the axial position of the intramedullary nail afford?
Excellent bending stability
What type of screws are placed through the bone and the intramedullary nail?
5.5-mm cortex screws
What is one major complication of interlocking intramedullary nails?
Fracture through the screw holes
What is a common outcome even in suboptimal repairs of femoral fractures?
Development of large calluses
What are the major advantages of using the locking compression plate (LCP) in femoral fracture repairs?
Enhanced stability and compression
How is a fracture reduced in the case of a long oblique fracture?
By clamping in an overriding position
What technique is applied in plate screws for additional compression and stability?
Lag technique
What must be done to prevent interference of screws in both plates?
Stagger the plates and insert screws perpendicularly
What is fundamental in the apposition of the plates in the lateral and cranial femur?
90º angle provides maximum stability and neutralizes the bending forces at fracture site
What is required to place the bone in alignment?
Vigourous traction so you need to attach the poney or foal to the table
Where are the gaps in the plate holes next to the screws typically filled with? A. Bone cement
B. Autologous cancellous bone
C. Antibiotic eluting material
D. Metal spacers
Antibiotic eluting material
Why is closed suction drainage essential in femoral fracture surgeries?
A. To minimize the risk of infection
B. To reduce swelling
C. To minimize accumulation of serum
D. To enhance healing
C. To minimize accumulation of serum
What is a critical step in the preparation for inserting an interlocking intramedullary nail?
Enlarging the medullary cavity
What is the main advantage of using interlocking intramedullary nails?
Excellent rotational and bending stability
How is the nail length preselected for an interlocking intramedullary nail insertion?
Using the length of the contralateral intact bone
What is a major complication associated with interlocking intramedullary nails?
Development of a fracture through the screw holes
How are cortex screws placed when using an interlocking intramedullary nail?
Perpendicular to the nail
What is the usual recommendation for follow-up radiographs in cases of femoral fractures?
6 weeks post-surgery
What age group is most commonly affected by distal femoral fractures?
Weanlings and yearlings
Where is the metaphyseal fragment usually positioned in most distal femoral fractures?
Caudally
Salter-Harris type II fracture of the distal femur. Lateromedial
caudocranial (C) radiographic views showing the repaired fracture. A DCS plate was applied laterally and augmented with a five-hole narrow DCP containing long screws penetrating the medial condyle. One single screw was buried in the articular surface to provide additional stability to the cranial aspect of the reconstruction. Longitudinally placed screws should augment the plate fixation. (