Clean Run Magazine - April 2010 - 33

Diagnosis
Diagnosis is made from the patient history, palpation, and diagnostic imaging (radiographs, CT scan, or MRI). Patellar luxation is graded on a scale from 1 (low) to 4 (more severe), based on severity of the luxation and anatomic bone deformity. The grade of luxation often correlates with the degree of lameness, but not always. •	 Grade 1 luxations are where the kneecap can be manually pushed out of the groove, but otherwise stays in the groove during normal activity. This degree of luxation is often asymptomatic and typically does not require treatment. However, it may become apparent in a performance dog, because the stress on the stifle joint is greater during periods of high speeds and jumping with concurrent tight turns. This manifests as a hesitation to jump or an occasional “skip” stride. Grade 2 luxations float in and out of the joint on their own, but spend more time in the groove than displaced. Patients with this grade of luxation often carry the limb intermittently while walking or going up and down stairs. Grade 3 luxations float in and out on their own, but are displaced from the groove the majority of the time. These cases often are continuously non-weightbearing lame or have a crouched, knock-knee gait. Grade 4 luxations remain displaced from the groove, and cannot be manually replaced within the groove. Grade 4 luxations, especially in large breed dogs with lateral luxations, are often the result of severe bone deformities of both the femur and tibia. Clinically, grade 4 luxations are characterized by an abnormal stance and gait, with a significant amount of weight being transferred to the front limbs. They usually require extensive surgery to be corrected and carry a more guarded prognosis. There are four key components that need to be assessed and corrected if abnormalities are found 1. 2. 3. 4. Integrity of the structures within the stifle Trochlear groove depth Skeletal alignment Joint capsule/retinaculum

•	

•	

The first portion of surgery is usually aimed at assessing the structures of the joint (cranial and caudal cruciate ligaments, menisci) and the trochlear groove. If the groove is shallow, then it is deepened surgically. There are four major ways to deepen the groove. The first is the abrasion trochleoplasty, which involves removing the joint cartilage and deepening the subchondral bone with either a bone rasp or a high-speed burr. While this is the easiest method of deepening the groove, it removes all of the natural cartilage that is in place (hyaline cartilage) and relies on the body’s ability to cover the exposed bone with fibrocartilage. Fibrocartilage does not have the same characteristics as normal cartilage, and the chances of osteoarthritis (OA) development or progression is higher with this procedure. Therefore, this procedure is best reserved for severe cases of eburnated (exposed) bone where there is already an absence of normal cartilage and there is truly nothing left to “preserve.” The next two options involve elevation of the contact portion of the cartilage with the underlying bone in either a wedge or block shape to create a recession. This allows the normal cartilage to remain relatively unharmed, while the underlying subchondral bone is removed. Once an adequate depth has been achieved, the wedge or block is replaced and is “press fit” into the recession or is held in place with a small pin. While both procedures allow for an adequate groove to be developed, research would suggest that the block shape allows for a deeper, wider groove and better contact at the apex of the trochlea, the location at which the patella is most likely to luxate. While this procedure is more technically demanding, it is my preferred method of deepening the trochlear groove. A fourth procedure available is chondroplasty, where a cartilage flap (without the underlying bone) is elevated. However, this procedure can only be performed in dogs less than 4-6 months of age and is rarely used.

•	

Patellar luxation is generally considered a mechanical lameness, in that it is not particularly painful (but is uncomfortable) when the kneecap is out of normal alignment. Lameness results because the dog is physically unable extend the knee in a normal manner. The condition can cause further discomfort because the chronic wearing away of normal cartilage from the ridges of the femur and patella subsequently results in the development of osteoarthritis. Medial patellar luxation also results in internal rotation of the entire knee, which can place additional stress on the cranial cruciate ligament and is a predisposing factor for developing a cruciate tear. Patellar luxation has also been noted secondary to severe hip dysplasia and subluxation (incomplete or partial dislocation) of the coxofemoral (hip) joint.

Treatment
Surgery is not mandatory for all patellar luxations, and recommendations vary from case to case. In our practice, we base the need for surgery on the type of work the dog is asked to do, the degree of lameness, chronicity of the lameness, and the degree of patellar luxation. In general, surgery typically coincides with a grade 2 patellar luxation or greater in a young, active patient.

Patellar luxation is a common condition seen in toy, miniature, and large breed dogs and is characterized by the kneecap dislocating or “floating” out of the trochlear groove. The kneecap can float either to the inside of the knee (medial luxation) or to the outside of the knee (lateral luxation). Medial luxations account for 80%-90% of all cases, regardless of the size or type of dog.
33

April 10

|

Clean Run



Clean Run Magazine - April 2010

Table of Contents for the Digital Edition of Clean Run Magazine - April 2010

Clean Run Magazine - April 2010
Contents
Editorializing: The Benefits of Joining an Agility Club
Tip of the Month
Everything You Always Wanted to Know About Agility…
Backyard Dogs
Applying Groundwork Principles to “Real” Agility Training
CR Central
Salo Jumping Work: The FAQs
Can You Handle It?
Congenital Conditions: Patellar Luxation
Nested Courses for a Small Universe
Building Your Plan: Developing Performance Goals, Part 1
What's My Plan?
Let’s Play! A Fail-safe Plan to Teach Your Dog to Love Toys, Part 2
Train to Maintain: Releases
Skill of the Month
It’s Your Turn! Cue #3: The Front Cross, Part 1
The Strategy of Colors: Orange You Glad You Walked Both Courses?
Technical Skills Can Help You in NADAC or Any Venue
Clean Run Magazine - April 2010 - Clean Run Magazine - April 2010
Clean Run Magazine - April 2010 - 2
Clean Run Magazine - April 2010 - Contents
Clean Run Magazine - April 2010 - 4
Clean Run Magazine - April 2010 - Editorializing: The Benefits of Joining an Agility Club
Clean Run Magazine - April 2010 - Tip of the Month
Clean Run Magazine - April 2010 - Everything You Always Wanted to Know About Agility…
Clean Run Magazine - April 2010 - Backyard Dogs
Clean Run Magazine - April 2010 - 9
Clean Run Magazine - April 2010 - 10
Clean Run Magazine - April 2010 - Applying Groundwork Principles to “Real” Agility Training
Clean Run Magazine - April 2010 - 12
Clean Run Magazine - April 2010 - 13
Clean Run Magazine - April 2010 - 14
Clean Run Magazine - April 2010 - 15
Clean Run Magazine - April 2010 - 16
Clean Run Magazine - April 2010 - 17
Clean Run Magazine - April 2010 - 18
Clean Run Magazine - April 2010 - CR Central
Clean Run Magazine - April 2010 - 20
Clean Run Magazine - April 2010 - 21
Clean Run Magazine - April 2010 - Salo Jumping Work: The FAQs
Clean Run Magazine - April 2010 - 23
Clean Run Magazine - April 2010 - 24
Clean Run Magazine - April 2010 - 25
Clean Run Magazine - April 2010 - 26
Clean Run Magazine - April 2010 - Can You Handle It?
Clean Run Magazine - April 2010 - 28
Clean Run Magazine - April 2010 - 29
Clean Run Magazine - April 2010 - 30
Clean Run Magazine - April 2010 - Congenital Conditions: Patellar Luxation
Clean Run Magazine - April 2010 - 32
Clean Run Magazine - April 2010 - 33
Clean Run Magazine - April 2010 - 34
Clean Run Magazine - April 2010 - 35
Clean Run Magazine - April 2010 - 36
Clean Run Magazine - April 2010 - Nested Courses for a Small Universe
Clean Run Magazine - April 2010 - 38
Clean Run Magazine - April 2010 - 39
Clean Run Magazine - April 2010 - Building Your Plan: Developing Performance Goals, Part 1
Clean Run Magazine - April 2010 - 41
Clean Run Magazine - April 2010 - 42
Clean Run Magazine - April 2010 - 43
Clean Run Magazine - April 2010 - 44
Clean Run Magazine - April 2010 - What's My Plan?
Clean Run Magazine - April 2010 - 46
Clean Run Magazine - April 2010 - 47
Clean Run Magazine - April 2010 - 48
Clean Run Magazine - April 2010 - 49
Clean Run Magazine - April 2010 - 50
Clean Run Magazine - April 2010 - Let’s Play! A Fail-safe Plan to Teach Your Dog to Love Toys, Part 2
Clean Run Magazine - April 2010 - 52
Clean Run Magazine - April 2010 - 53
Clean Run Magazine - April 2010 - 54
Clean Run Magazine - April 2010 - 55
Clean Run Magazine - April 2010 - Train to Maintain: Releases
Clean Run Magazine - April 2010 - 57
Clean Run Magazine - April 2010 - 58
Clean Run Magazine - April 2010 - 59
Clean Run Magazine - April 2010 - 60
Clean Run Magazine - April 2010 - 61
Clean Run Magazine - April 2010 - 62
Clean Run Magazine - April 2010 - Skill of the Month
Clean Run Magazine - April 2010 - 64
Clean Run Magazine - April 2010 - 65
Clean Run Magazine - April 2010 - 66
Clean Run Magazine - April 2010 - It’s Your Turn! Cue #3: The Front Cross, Part 1
Clean Run Magazine - April 2010 - 68
Clean Run Magazine - April 2010 - 69
Clean Run Magazine - April 2010 - 70
Clean Run Magazine - April 2010 - The Strategy of Colors: Orange You Glad You Walked Both Courses?
Clean Run Magazine - April 2010 - 72
Clean Run Magazine - April 2010 - 73
Clean Run Magazine - April 2010 - 74
Clean Run Magazine - April 2010 - 75
Clean Run Magazine - April 2010 - Technical Skills Can Help You in NADAC or Any Venue
Clean Run Magazine - April 2010 - 77
Clean Run Magazine - April 2010 - 78
Clean Run Magazine - April 2010 - 79
Clean Run Magazine - April 2010 - 80
Clean Run Magazine - April 2010 - 81
Clean Run Magazine - April 2010 - 82
Clean Run Magazine - April 2010 - 83
Clean Run Magazine - April 2010 - 84
https://www.nxtbook.com/nxtbooks/cleanrun/1220
https://www.nxtbook.com/nxtbooks/cleanrun/1120
https://www.nxtbook.com/nxtbooks/cleanrun/1020
https://www.nxtbook.com/nxtbooks/cleanrun/0920
https://www.nxtbook.com/nxtbooks/cleanrun/0820
https://www.nxtbook.com/nxtbooks/cleanrun/0720
https://www.nxtbook.com/nxtbooks/cleanrun/0620
https://www.nxtbook.com/nxtbooks/cleanrun/0520
https://www.nxtbook.com/nxtbooks/cleanrun/0420
https://www.nxtbook.com/nxtbooks/cleanrun/0320
https://www.nxtbook.com/nxtbooks/cleanrun/0220
https://www.nxtbook.com/nxtbooks/cleanrun/0120
https://www.nxtbook.com/nxtbooks/cleanrun/1219
https://www.nxtbook.com/nxtbooks/cleanrun/1119
https://www.nxtbook.com/nxtbooks/cleanrun/1019
https://www.nxtbook.com/nxtbooks/cleanrun/0919
https://www.nxtbook.com/nxtbooks/cleanrun/0819
https://www.nxtbook.com/nxtbooks/cleanrun/0719
https://www.nxtbook.com/nxtbooks/cleanrun/0619
https://www.nxtbook.com/nxtbooks/cleanrun/0519
https://www.nxtbook.com/nxtbooks/cleanrun/0419
https://www.nxtbook.com/nxtbooks/cleanrun/0319
https://www.nxtbook.com/nxtbooks/cleanrun/0219
https://www.nxtbook.com/nxtbooks/cleanrun/0119
https://www.nxtbook.com/nxtbooks/cleanrun/1218
https://www.nxtbook.com/nxtbooks/cleanrun/1118
https://www.nxtbook.com/nxtbooks/cleanrun/1018
https://www.nxtbook.com/nxtbooks/cleanrun/0918
https://www.nxtbook.com/nxtbooks/cleanrun/0818
https://www.nxtbook.com/nxtbooks/cleanrun/0718
https://www.nxtbook.com/nxtbooks/cleanrun/0618
https://www.nxtbook.com/nxtbooks/cleanrun/0518
https://www.nxtbook.com/nxtbooks/cleanrun/0418
https://www.nxtbook.com/nxtbooks/cleanrun/0318
https://www.nxtbook.com/nxtbooks/cleanrun/0218
https://www.nxtbook.com/nxtbooks/cleanrun/0118
https://www.nxtbook.com/nxtbooks/cleanrun/1217
https://www.nxtbook.com/nxtbooks/cleanrun/1117
https://www.nxtbook.com/nxtbooks/cleanrun/1017
https://www.nxtbook.com/nxtbooks/cleanrun/0917
https://www.nxtbook.com/nxtbooks/cleanrun/0817
https://www.nxtbook.com/nxtbooks/cleanrun/0717
https://www.nxtbook.com/nxtbooks/cleanrun/0617
https://www.nxtbook.com/nxtbooks/cleanrun/0517
https://www.nxtbook.com/nxtbooks/cleanrun/0417
https://www.nxtbook.com/nxtbooks/cleanrun/0317
https://www.nxtbook.com/nxtbooks/cleanrun/0217
https://www.nxtbook.com/nxtbooks/cleanrun/0117
https://www.nxtbook.com/nxtbooks/cleanrun/1216
https://www.nxtbook.com/nxtbooks/cleanrun/1116
https://www.nxtbook.com/nxtbooks/cleanrun/1016
https://www.nxtbook.com/nxtbooks/cleanrun/0916
https://www.nxtbook.com/nxtbooks/cleanrun/0816
https://www.nxtbook.com/nxtbooks/cleanrun/0716
https://www.nxtbook.com/nxtbooks/cleanrun/0616
https://www.nxtbook.com/nxtbooks/cleanrun/0516
https://www.nxtbook.com/nxtbooks/cleanrun/0416
https://www.nxtbook.com/nxtbooks/cleanrun/0316
https://www.nxtbook.com/nxtbooks/cleanrun/0216
https://www.nxtbook.com/nxtbooks/cleanrun/0116
https://www.nxtbook.com/nxtbooks/cleanrun/1215
https://www.nxtbook.com/nxtbooks/cleanrun/1115
https://www.nxtbook.com/nxtbooks/cleanrun/1015
https://www.nxtbook.com/nxtbooks/cleanrun/0915
https://www.nxtbook.com/nxtbooks/cleanrun/0815
https://www.nxtbook.com/nxtbooks/cleanrun/0715
https://www.nxtbook.com/nxtbooks/cleanrun/0615
https://www.nxtbook.com/nxtbooks/cleanrun/0515
https://www.nxtbook.com/nxtbooks/cleanrun/0415
https://www.nxtbook.com/nxtbooks/cleanrun/0315
https://www.nxtbook.com/nxtbooks/cleanrun/0215
https://www.nxtbook.com/nxtbooks/cleanrun/0115
https://www.nxtbook.com/nxtbooks/cleanrun/1214
https://www.nxtbook.com/nxtbooks/cleanrun/1114
https://www.nxtbook.com/nxtbooks/cleanrun/1014
https://www.nxtbook.com/nxtbooks/cleanrun/0914
https://www.nxtbook.com/nxtbooks/cleanrun/0814
https://www.nxtbook.com/nxtbooks/cleanrun/0714
https://www.nxtbook.com/nxtbooks/cleanrun/0614
https://www.nxtbook.com/nxtbooks/cleanrun/0514
https://www.nxtbook.com/nxtbooks/cleanrun/0414
https://www.nxtbook.com/nxtbooks/cleanrun/0314
https://www.nxtbook.com/nxtbooks/cleanrun/0214
https://www.nxtbook.com/nxtbooks/cleanrun/0114
https://www.nxtbook.com/nxtbooks/cleanrun/1213
https://www.nxtbook.com/nxtbooks/cleanrun/1113
https://www.nxtbook.com/nxtbooks/cleanrun/1013
https://www.nxtbook.com/nxtbooks/cleanrun/0913
https://www.nxtbook.com/nxtbooks/cleanrun/0813
https://www.nxtbook.com/nxtbooks/cleanrun/0713
https://www.nxtbook.com/nxtbooks/cleanrun/0613
https://www.nxtbook.com/nxtbooks/cleanrun/0513
https://www.nxtbook.com/nxtbooks/cleanrun/0413
https://www.nxtbook.com/nxtbooks/cleanrun/0313
https://www.nxtbook.com/nxtbooks/cleanrun/0213
https://www.nxtbook.com/nxtbooks/cleanrun/0113
https://www.nxtbook.com/nxtbooks/cleanrun/1212
https://www.nxtbook.com/nxtbooks/cleanrun/1112
https://www.nxtbook.com/nxtbooks/cleanrun/1012
https://www.nxtbook.com/nxtbooks/cleanrun/0912
https://www.nxtbook.com/nxtbooks/cleanrun/0812
https://www.nxtbook.com/nxtbooks/cleanrun/0712
https://www.nxtbook.com/nxtbooks/cleanrun/0612
https://www.nxtbook.com/nxtbooks/cleanrun/0512
https://www.nxtbook.com/nxtbooks/cleanrun/0412
https://www.nxtbook.com/nxtbooks/cleanrun/0312
https://www.nxtbook.com/nxtbooks/cleanrun/0212
https://www.nxtbook.com/nxtbooks/cleanrun/0112
https://www.nxtbook.com/nxtbooks/cleanrun/1211
https://www.nxtbook.com/nxtbooks/cleanrun/1111
https://www.nxtbook.com/nxtbooks/cleanrun/1011
https://www.nxtbook.com/nxtbooks/cleanrun/0911
https://www.nxtbook.com/nxtbooks/cleanrun/0811
https://www.nxtbook.com/nxtbooks/cleanrun/0711
https://www.nxtbook.com/nxtbooks/cleanrun/0611
https://www.nxtbook.com/nxtbooks/cleanrun/0511
https://www.nxtbook.com/nxtbooks/cleanrun/0411
https://www.nxtbook.com/nxtbooks/cleanrun/0311
https://www.nxtbook.com/nxtbooks/cleanrun/0211
https://www.nxtbook.com/nxtbooks/cleanrun/0111
https://www.nxtbook.com/nxtbooks/cleanrun/1210
https://www.nxtbook.com/nxtbooks/cleanrun/1110
https://www.nxtbook.com/nxtbooks/cleanrun/1010
https://www.nxtbook.com/nxtbooks/cleanrun/0910
https://www.nxtbook.com/nxtbooks/cleanrun/0810
https://www.nxtbook.com/nxtbooks/cleanrun/0710
https://www.nxtbook.com/nxtbooks/cleanrun/0610
https://www.nxtbook.com/nxtbooks/cleanrun/0510
https://www.nxtbook.com/nxtbooks/cleanrun/0410
https://www.nxtbook.com/nxtbooks/cleanrun/0310
https://www.nxtbook.com/nxtbooks/cleanrun/0210
https://www.nxtbook.com/nxtbooks/cleanrun/0110
https://www.nxtbook.com/nxtbooks/cleanrun/1209
https://www.nxtbook.com/nxtbooks/cleanrun/1109
https://www.nxtbook.com/nxtbooks/cleanrun/1009
https://www.nxtbook.com/nxtbooks/cleanrun/0909
https://www.nxtbook.com/nxtbooks/cleanrun/0809
https://www.nxtbook.com/nxtbooks/cleanrun/0709
https://www.nxtbook.com/nxtbooks/cleanrun/comp-demo
https://www.nxtbook.com/nxtbooks/cleanrun/0609
https://www.nxtbook.com/nxtbooks/cleanrun/0509
https://www.nxtbook.com/nxtbooks/cleanrun/0409
https://www.nxtbook.com/nxtbooks/cleanrun/0309
https://www.nxtbook.com/nxtbooks/cleanrun/0209
https://www.nxtbook.com/nxtbooks/cleanrun/0109
https://www.nxtbook.com/nxtbooks/cleanrun/1208
https://www.nxtbook.com/nxtbooks/cleanrun/1108
https://www.nxtbook.com/nxtbooks/cleanrun/1008
https://www.nxtbook.com/nxtbooks/cleanrun/0908
https://www.nxtbook.com/nxtbooks/cleanrun/0808
https://www.nxtbook.com/nxtbooks/cleanrun/0708
https://www.nxtbook.com/nxtbooks/cleanrun/0608
https://www.nxtbook.com/nxtbooks/cleanrun/0508
https://www.nxtbook.com/nxtbooks/cleanrun/0408
https://www.nxtbook.com/nxtbooks/cleanrun/0308
https://www.nxtbook.com/nxtbooks/cleanrun/0208
https://www.nxtbook.com/nxtbooks/cleanrun/0108
https://www.nxtbook.com/nxtbooks/cleanrun/1207
https://www.nxtbook.com/nxtbooks/cleanrun/1107
https://www.nxtbook.com/nxtbooks/cleanrun/1007
https://www.nxtbook.com/nxtbooks/cleanrun/0907
https://www.nxtbook.com/nxtbooks/cleanrun/0807
https://www.nxtbook.com/nxtbooks/cleanrun/0707
https://www.nxtbook.com/nxtbooks/cleanrun/0607
https://www.nxtbook.com/nxtbooks/cleanrun/0507
https://www.nxtbook.com/nxtbooks/cleanrun/0407
https://www.nxtbook.com/nxtbooks/cleanrun/0307
https://www.nxtbook.com/nxtbooks/cleanrun/0207
https://www.nxtbook.com/nxtbooks/cleanrun/0107
https://www.nxtbook.com/nxtbooks/cleanrun/1206
https://www.nxtbook.com/nxtbooks/cleanrun/1106
https://www.nxtbook.com/nxtbooks/cleanrun/1006
https://www.nxtbook.com/nxtbooks/cleanrun/0906
https://www.nxtbook.com/nxtbooks/cleanrun/0806
https://www.nxtbook.com/nxtbooks/cleanrun/0706
https://www.nxtbook.com/nxtbooks/cleanrun/0606
https://www.nxtbook.com/nxtbooks/cleanrun/0506
https://www.nxtbook.com/nxtbooks/cleanrun/0406
https://www.nxtbook.com/nxtbooks/cleanrun/0306
https://www.nxtbook.com/nxtbooks/cleanrun/0206
https://www.nxtbook.com/nxtbooks/cleanrun/0106
https://www.nxtbookmedia.com