SA Ortho - Patellar Lux Flashcards

1
Q

Congenital patellar luxation
Occurs in
Placement

A

Small toy breeds
Medial lux is most common

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2
Q

Traumatic patellar lux
Common group
Placement

A

Large breeds
Lateral lux is most common

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3
Q

Anatomy of medial pat lux

A

Patella is a sesamoid bone in quad tendon & patellar lig

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4
Q

Pathogenesis of medial pat lig

A

Unknown
May result from abnormal hip conformation

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5
Q

Another mechanism malfunction that could lead to med pat lux

A

Displacement of quadriceps mechanism could lead to pat lux

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6
Q

Angle of inclination to will most likely lead to medial pat lux

A

Coxa Vera - problem of angulation in hip expressed in stifle joint.

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7
Q

Secondary changes in limb of med pat lux

A

Med displacement of quads
Lateral bowing of femur
Torsion of distal femur
Shallow trochlear groove
Stifle instability
Medial displacement of tibial tuberosity

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8
Q

Clinical signs
(Can increase w grades)

A

Hoping lameness
Crouched - bow legged
Lameness could increase w development of DJD

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9
Q

Diagnosing pat lux

A

Using clinical signs/presentation
Physical exam findings
Radiographs

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10
Q

Grading pat lux
Grade 1

A

Patella can be manually luxation, but reduces spontaneously
Rarely lame, occasional skip
Minimal medial tibial rotation

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11
Q

Grading pat lux
Grade 2

A

Patella luxates spontaneously, reduced spontaneously with rotation of the tibia
Lameness varies - occasionally skip /WB lameness
Medial tibial rotation - up to 30*

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12
Q

Grading pat lux
Grade 3

A

Patella is luxated but can reluctantly be reduced
Chronic lameness
Medial tibial rotation of 30-60*
Moderate angular or torsional deformity

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13
Q

Grading pat lux
Grade 4

A

Patella is luxated continually and cannot be manually reduced
Limb is carried /crouched stance
Medial tibial rotation of 60-90*
Marked angular and torsional deformities

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14
Q

Radiograph shots for diagnosis of MPL

A

Skyline with rotation/angulation

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15
Q

Radio graphic signs of MPL

A

Displacement of patella on craniocaudal view
Shallow trochlear groove
Secondary OA

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16
Q

Patellar lux - surgery

A

Realign extensors apparatus
Normalize forces acting on physis/cartilage
Stabilize the patella in trochlear groove

17
Q

Components of Patlux repair

A

Soft tissue reconstruction
Bone reconstruction

18
Q

Aspects of soft tissue reconstruction

A

Imbrication of lateral retinacular fascia
Patellar and tibial anti rotational sutures
Medial release (Desmotomy)

19
Q

Aspects of bone reconstruction for pat lux

A

Tibial tuberosity transposition
- transpose laterally for medial
- transpose medially for lateral
Corrective osteotomies of femur/tibia

20
Q

Trochleoplasty techniques

A

Sulcoplasty
Wedge recession
Block recession
Chondroplasty

21
Q

Trochleoplasty

A

Deepening of trochlear groove to depth of 1/2 patella thickness

22
Q

Trochleoplasty block recession

A

Preserves more cartilage
Better for articular contact
Improved depth proximally

23
Q

Prognosis for Pat lux surgical repair

A

Improves limb function
DOES NOT prevent progression of OA
Reluxation is common
-48%
- however usually mild