DARTHROPLASTY – Practical Training – Wet Labs 11-12th November 2016 – Warsaw and Legionowo, Poland. Legwet Veterinary Clinic, Centro de Cirurgia Veterinária de Loures and KK-Art held a practical training on 11-12th of November 2016, in Warsaw and Legionowo – Poland. It was attended by veterinary doctors from several countries. You can see the slideshow presentation by Dr. Rafael Lourenço Part 1

1. WARSAW
11-12 November 2016
PART 1
www.darthroplasty.com

2. “Dogs are born with normal hips”
1
Alexander, J.W. (1992) The Veterinary Clinics of North America. Vol 22, Number 3

3. “Embryonically, the hip is laid down
as a single unit from mesenchymal tissue,
and it develops normally as long as the
components are left in full contact”
2
Strayer LM (1943) “The embriology of the human hip joint” Yale J Biol Med 16: 13-26

4. Human 25 mm embryo (8 weeks)
3

5. 4
12 days
2 months
8 months
1 month
4 months
2 years

6. 5

7. 6
• 87 dogs from birth to 30 days of age were
dissected.
• In 3 of these dogs (all were 30 days old)
he found an oedematous femoral head
ligament with a few torn fibers with dots of
haemorrhage at the point of the tears.
Riser, W (1975) The Dysplastic Hip Joint: Radiologic and
Histologic Development Vet Pathol 1975 12: 279

8. 7
• In dogs that were 30 to 60 days of age
the first signs detected by radiography
were femoral head subluxation and a
retardation in the development of the
craniodorsal acetabular rim.
Riser, W (1975) The Dysplastic Hip Joint: Radiologic and
Histologic Development Vet Pathol 1975 12: 279

9. 8
5 month old German Shepherd

10. 9
• Lust et al used a lineage of Labrador Retrievers
with high risk for dysplasia (90% dysplastic
offspring) to study the early stage of the disease.
• Most joints studied were from 3 to 6 month old
dogs.
• He found a proliferative synovitis (from mild
to severe) in all joints studied from the high
risk group. In the control group (Labrador
Retrievers) 50% of the joints had synovitis, all
in the mildest form.
Lust, G; Summers, B. (1981) Early, asymptomatic stage of
degenerative joint disease in canine hip joints.
Am J Vet Research, vol 42, nr 11, pg 1849-1855.

11. 10
“This study provides evidence that
synovial fluid and round ligament volume
increase early in the course of osteoarthritis
in dogs with incipient hip dysplasia.”
“Microscopically, studies of the synovial
membranes support the view that these
changes result from inflammation.”
Lust, G; Summers, B. (1981) Early, asymptomatic stage of
degenerative joint disease in canine hip joints.
Am J Vet Research, vol 42, nr 11, pg 1849-1855.

12. Synovitis
Cartilage
damage
Radiographic
signs of disease
11
The data points to a time sequence of events:
It is therefore very likely that ALL of our patients
at the time of radiographic diagnosis have some
level of cartilage damage.
Lust, G; Summers, B. (1981) Early, asymptomatic stage of
degenerative joint disease in canine hip joints.
Am J Vet Research, vol 42, nr 11, pg 1849-1855.

13. 12
At arthroscopy 96% of the joints
had some form of cartilage lesion
50% of the joints had either deep fissuring
or full thickness cartilage loss
81% had partial tearing of the femoral head
ligament and 7% a complete rupture
93% of the joints had lesions of the labrum
(tearing in 44% and avulsion in 49%)
Holsworth, IG, et al (2005) Comparison of arthroscopic and
radiographic abnormalities in the hip joints of juvenile dogs
with hip dysplasia JAVMA, vol 227, nr 7: 1091-1094
The authors studied 52 dogs (age 5½ to 15½ months old);
Total number of hips = 70
Radiographically, 43% of the joints had NO signs of DJD
and 33% considered to have mild signs

14. 13
Hip Fluid Seal
during distractive forces
helps to generate negative
intra-articular pressure
resulting in a stabilizing force
– Hip Fluid Seal or Suction Seal –
The acetabular labrum constrains the fluid in the joint,
sealing it from fluid extravasion.
during loading
action over intra-articular
fluid pressure

15. 14
Ferguson et al. (2003) An in vitro investigation of the
acetabular labral seal in hip joint mechanics.
Journal of Biomechanics 36 (2003) 171–178
Hydrostatic fluid pressurisation
within the intra-articular space
is greater with the labrum than
without it.
Cartilage consolidation is
quicker without the Labrum
The Labrum adds an extra resistance to the flow path
for interstitial fluid expression

16. 15
• Resistance to rotation, which reflects
articular cartilage friction, was significantly
increased following focal labrectomy at 1-3
times Body Weight loading, and following
complete labrectomy at all load levels.
• The acetabular labrum appears to maintain
a low friction environment, possibly by
sealing the joint from fluid exudation.
Yongnam Song et al (2012) Articular cartilage friction increases in
hip joints after the removal of acetabular labrum.
Journal of Biomechanics 45 (2012) 524–530

17. 16
Nepple et al (2014) The hip fluid seal - Part II: The effect of an acetabular
labral tear, repair, resection, and reconstruction on hip stability to
distraction. Knee Surg Sports Traumatol Arthrosc (2014) 22: 730–736

18. 17
• Surgically executed unilateral eversion of the
labrum in 20 Mongrel puppies, 6 week old.
• He observed dysplastic characteristics
(subluxation, shallow acetabuli) and gross
cartilage abnormalities in all operated joints.
• In his words: “despite the tight closure of the
joint capsule after eversion of the acetabular
labrum, acetabular dysplasia with subluxation
of the femoral head gradually developed
following surgery”.
Young-Hoo Kim (1984) Acetabular dysplasia and osteoarthritis
developed by an eversion of the acetabular labrum.
Yonsei Medical Journal vol 25, nr 2, 1984

19. 18
Coxofemoral joints in
which subluxation
was demonstrated
radiographically had
greater synovial fluid
and round ligament
volumes compared
with non-subluxated,
normal joints.
• Low prevalence line of dogs:
usually free of dysplasia at 9 months of age
• High-dysplastic line: 90% dysplastic at 9 months of age
Lust, G et al (1980) A Relationship between degree of laxity and
synovial fluid volume in coxofemoral joints of dogs predisposed
for hip dysplasia. Am J Vet Research, vol 41, nr 1, pg 55-60

20. 19
Lust, G et al (1980) A Relationship between degree of laxity and
synovial fluid volume in coxofemoral joints of dogs predisposed
for hip dysplasia. Am J Vet Research, vol 41, nr 1, pg 55-60
Subluxation was observed only in the presence of greater
than normal synovial fluid and round ligament volumes.
These data indicate that increased synovial fluid volume is one
biomechanical component of abnormal laxity and subluxation.

21. 20
Riser (1975) Surgically Induced Hip Dysplasia
Vet Pathol 12 : 306-315 (1975)
• In 5 dogs the tendons of the obturators
(int and ext) and the gemelli were surgically
severed at 4 months of age.
• All operated hips became severely dysplastic.
Muscular component destruction
also creates dysplasia

22. There are several mechanisms acting
together and contributing to stability
… …
labrum
fluid seal
capsule
muscle / tendon
units
neurological
networks
21

23. 22
Pountney, T; et al (2006) Hip dislocation in cerebral palsy.
BMJ vol 332, 1 APRIL 2006
• In children with cerebral palsy the hip is
normal at birth but the effects of delayed
motor development lead to dysplasia.
Asymmetrical activity of the muscles
surrounding the hip and lack of load bearing
affect bone development and are the main
causes of subluxation and dislocation.
• Lateral migration of the hip (subluxation or
partial dislocation) occurs in 30-60% of
children with cerebral palsy who are not
walking independently at 5 years.

24. • 92 young dogs (less than 12 months old), hip dysplasia prone on
the basis of genealogical records were studied at necropsy
• observed DJD of the Hip in 71%; of the Stifle in 22%
and of the Shoulder in 38%
• 40% had Multiple Joints Involved (excludes dogs with only same
joint bilaterally affected)
• and the ELBOW was not studied
• “Possibly, there is a systemic basis for joint degeneration with
variable expression in different joints”
• This can link hip dysplasia to the other disease that are caused
by abnormal progression of endochondral ossification (Shoulder
OCD, Elbow Dysplasia, etc ...)
Olsewski, J M; Lust, G; et al (1983) Degenerative Joint Disease:
Multiple Joint Involvement in Young and Mature Dogs.
Am J Vet Research, 1983, vol 44, nr 7
23

25. Birgit Lieser (2003); Morphological and biomechanical properties of the hip joint
in the Dog (Canis familiaris); Dissertation for the veterinary doctorate - Veterinary
Faculty of the Ludwig Maximilian University of Munich
24
BODY WEIGHT
25% 50% 75% 100%
150% 200% 250% 300%
400%

26. 25
Birgit Lieser (2003); Morphological and biomechanical properties of the hip joint
in the Dog (Canis familiaris); Dissertation for the veterinary doctorate - Veterinary
Faculty of the Ludwig Maximilian University of Munich
• At low loads and physiological angulation contact areas were
mainly found at the peripheral margin of the cranial and
caudal part of the facies lunata and caput ossis femoris
• At the cranial roof of the acetabulum a joint space was evident
in the loaded specimens up to 75% body weight.
Under increasing loads the contact areas expanded towards
the joint centre.
• The results of this study established proof of the
inhomogeneous load distribution in the canine hip joint.
For the first time it was shown that the canine hip joint is not
congruous as commonly assumed but maintains a
physiological incongruence.
This guarantees for an optimal load distribution in the joint and
for a better nutrition of the joint cartilage

27. 26
The physiological
incongruence
may contribute to
optimal load
distribution
specially on
higher load values
Birgit Lieser (2003); Morphological and biomechanical properties of the hip joint
in the Dog (Canis familiaris); Dissertation for the veterinary doctorate - Veterinary
Faculty of the Ludwig Maximilian University of Munich

28. 27
• Micro-fractures of the
acetabular rim (Riser)
• Capsule stretching
and tearing
• Inflammation
In the young dog
pain has been attributed to:
• Degenerative joint
disease and its
consequences in
cartilage and
subchondral bone
In the older dog
pain has been attributed to:

29. 28
C.H. Huang, et al. (2013) The Innervation of Canine Hip Joint Capsule:
An Anatomic Study Anat. Histol. Embryol. 42 (2013) 425-431
• The canine hip joint capsule receives
multiple innervations from articular
branches of 4 nerves.
They are articular nerve fibres of femoral,
obturator, cranial gluteal and sciatic
nerves from the cranioventral, caudoventral,
craniolateral and dorsolateral directions of
the joint, respectively

30. 29
C.H. Huang, et al. (2013) The Innervation of Canine Hip Joint Capsule:
An Anatomic Study Anat. Histol. Embryol. 42 (2013) 425-431

31. • Does it have an effect on full thickness
cartilage loss and nociception by the
subchondral bone? NO
• Does it have an effect on the total
innervation of the hip capsule? NO
• Is re-inervation a possibility? YES
30
Hip denervation has been proposed
as a palliative measure for hip dysplasia
These questions and others we must ask
of the DARTHROPLASTY

32. In my opinion there is a class of hip dysplasia affected dogs
that should be called compensated cases on a clinical basis.
31
Conservative treatment

33. 32
Conservative treatment

34. 33

35. WARSAW
11-12 November 2016
END OF PART 1
www.darthroplasty.com