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Question 1

Luxation

Answer 1

Luxation = displacement of articular surfaces from the normal position within a joint.
Subluxation = Partial dislocation from the normal position within a joint.

Question 2

True or False luxations and subluxations can be congenital or acquired

Answer 2

True.

Question 3

How can Luxation and Subluxation be repaired?

Answer 3

Repaired via open or closed reduction

Question 4

What is closed reduction - how is it performed?

Answer 4

Closed reduction is done by manipulating the joint into correct anatomical alignment. This should be carried out under general anaesthesia due to pain felt under sedation. X-rays should be taken afterwards to ensure the reduction was successful

Question 5

What is open reduction

Answer 5

Open reduction is the surgical approach where the luxated bones are visualised and manipulated back into the joint.

Question 6

Closed reduction patients should have what applied? and for how long?

Answer 6

A VALPEAU or EHMER should be applied and kept on for 5-7 days

Question 7

How long should exercise be restricted for, for a luxation?

Answer 7

3-4 weeks

Question 8

What is an Ehmer sling?

Answer 8

Ehmer sling is used to support the hind limb following reduction of hip luxation.

Question 9

What is a Valpeau sling?

Answer 9

This is used to support the shoulder joint following luxation, bursitis, and non-displacement fracture of the scapula or humerus.

Question 10

What is the most common luxation

Answer 10

Patella luxation

Question 11

What is a patella luxation

Answer 11

A luxating patella is a condition in which the patella dislocates and moves out of the trochlear grove causing pain and discomfort to the patient.

Question 12

What is a luxating patella commonly found in?

Answer 12

Small cats and dogs - basset hounds are prone due to the abnormal shape of the femour and tibia - The curves of the bones work with the forces of the quadriceps muscles to displace the patella.

Question 13

Where is the patella found? and how does it work?

Answer 13

The patella is found on the cranial surface of the stifle; it sits in the trochlear groove and is held in place by tendons and ligaments. It moves every time the knee bends or straightens

Question 14

What part of the body is affected by a luxating patella?

Answer 14

Hind legs - can affect one or both

Question 15

Clinical Signs

Answer 15

1. Intermittent lameness
2. Pain
3. Affected limb may temporarily lock into place
4. Skipping gait

Question 16

What causes a luxating patella

Answer 16

Congenital abnormality in the formation of the patellar groove. The trochlear groove fails to develop normally, and is too shallow. This can be apparent as early as four months old. The other cause is due to trauma.

Question 17

Name the 4 grades involved with luxating patellas

Answer 17

Grade 1: The patella is positioned normally but can be luxated with slight manual pressure
Grade 2: Spontaneous luxation occurs, however it can reduce spontaneously or can be replaced manually
Grade 3: The patella is luxated most of the time, however it can be replace manually
Grade 4: The patella cannot be reduced manually

Question 18

Diagnosis of the patella involves?

Answer 18

Examined by the vet
Sedated xrays to evaluate alignment
Arthrocentesis - aspirate synovial fluid for analysis of infections

Question 19

How can a luxating patella be managed?

Answer 19

Medical treatment or surgery for patellas graded 2-4

Question 20

What surgerys are there for luxating patellas?

Answer 20

Abrasion Trochleoplasty
Trochlear Wedge Sulcoplasty/ Recession
Trochlear Block Sulcoplasty/ Recession
Tibial Tuberosity Transposition

Question 21

What is Abrasion Trochleoplasty? + instruments needed

Answer 21

This involves the removal of the articular cartilage and subchondral bone from the trochlea sulcus. It is less technically demanding than other surgical repair options. Instrumentation required: Gelpies, Rongeurs/or Bone Rasp.

Question 22

What is Trochlear Wedge Sulcoplasty/ Recession? + instruments needed

Answer 22

This involves the removal of a ‘V shaped’ wedge of bone and cartilage from the femoral trochlear sulcus, followed by replacement of the original wedge in a recessed position. This surgical approach is more technically demanding. Instrumentation required: Fine toothed hand saw blade, Rongeurs and the Gelpies.

Question 23

What is Trochlear Block Sulcoplasty/ Recession? + instruments needed

Answer 23

This involves the removal of a block from the femoral trochlea sulcus. This surgical approach provides a bigger proximal recession, which may provide more stability for the patient. It is a technically demanding surgery. Instrumentation required: Fine tooth hand-saw blade, modular osteotome, Mallet, Rongeurs, and the Gelpies.

Question 24

What is Tibial Tuberosity Transposition? + Instruments needed

Answer 24

This surgical approach is used to improve alignment of the patellar mechanisms for patients who have an abaxially displaced tibial tuberosity. This involves cutting the tibial tuberosity and transpositioning laterally to achieve neutral orientation of the patella ligament. Instrumentation required: gelpies, mallet, rongeurs, Bone Rasp, IM Pins (K wire), Jacobs chuck handle and key, sagittal saw, listen bone cutters, modular osteotome, cerclage wire, wire twisters (possibly lag screw).

Question 25

How is the clipping performed?

Answer 25

1. dorsal or lateral recumbency
2. Place non sterile glove over foot of the limb needing surgery
3. Wrap in a non sterile bandage or micropore tape and hang this to an iv pole so the limb is elevated prior to the surgical prep.

Question 26

Where do you clip?

Answer 26

Best practice to clip the fur from the hip to the tarsus circumferentially, this is so that the surgeon can move and manipulate the leg without contaminating the surgical field

Question 27

Prep

Answer 27

Linear scrub is preferred

Question 28

Surgical positioning

Answer 28

dorsal recumbency however some vets request lateral recumbency with the affected limb uppermost

Question 29

Instruments

Answer 29

Four quarter drape
General surgical kit
Rongeurs 
Gelpies
Fine tooth hand saw