Ortho Hindlimb Flashcards
How many tarsal bones are there? List them
7
- calcaneus
- talus (tibiotarsal bone)
- central tarsal bone
- 1st, 2nd, 3rd, 4th tarsal bones
What are the parts of the talus?
- Body with 2 ridges to form trochlea
- Head articulates with central tarsal bone (distal portion)
What are the parts of the calcaneus?
- tuber calcanei - connects with cancaneal tendon
- sustentaculum tali - medial side
What are the articulations of the tarsus and what do they connect?
- tarsocrural – talus to tibia
- talocalcaneal – talus to sustentaculum tali
- talocalcaneal central – talus/sustentaculum tali to central tarsal
- calcaneoquartal – calcaneus to 4th tarsal bone
- centrodistal (aka inter tarsal) – central tarsal to T1-3
- tarsometatarsal (aka proximal inter tarsal) – tarsal bones to metatarsals
What additional sesamoid bones are present in the Greyhound breed?
- Lateral plantar tarsometatarsal 50%
- small medial inter tarsal tarsometatarsal 27%
Normal standing angle of tarsus in dog vs. cat
Dog = 135 - 145 degrees
Cat = 115 - 125 degrees
What is the range of motion of the tarsus in dog vs cat
Dog = 39 deg flexion, 164 deg extension
Cat = 22 deg flexion, 167 deg extension
What is the prognosis of fracture of talus?
Guarded d/t severe OA
What are 4 fracture patterns of calcaneus?
- Midbody (comminution)
- Slab fractures (dorsomedially or laterally)
- Avulsion involving plantar ligaments
- SH I - avulsion of proximal epiphysis
Prognosis for calcaneal fracture repair?
Good.
Greyhounds good for function, poor for return to racing
What stance may be seen with fracture of calcaneus?
Pseudo-plantigrade stance
What breed commonly gets central tarsal bone fractures?
Greyhounds. RIGHT side
accounts for 79% of tarsal injuries
List 5 patterns of central tarsal bone fracture
- Non-displaced dorsal slab
- Displaced dorsal slab
- Large displaced medial slab
- Medial slab with dorsal slab
- Comminuted
List treatment and prognosis for central tarsal bone fractures
- extension splint to prevent collapse
- screws in lag fashion optimum for types I-IV
- can do conservative for I-II
- arthrodesis?
- Prognosis can be good with successful surgery
What are treatment options for tarsal collateral ligament rupture? Prognosis?
Prognosis for short collateral rupture?
- primary repair with locking loop +/- internal splint (bone anchors, screws and washers, nylon, monofilament wire)
- transosseous tunnels to place suture w/o metal
- Prognosis - fair to guarded if medial and lateral instability
- Short collateral - good
What tendons make up the calcaneal tendon?
- Paired gastrocnemius
- Gracilis
- Semitendinosus
- Biceps femoris
- Superficial digital flexor
What are the 2 most common disruptions of the calcaneal tendon?
Of the latter, what breeds are over represented?
- Traumatic complete tear
- Partial separation of the gastrocnemius
- Labradors, Doberman Pinscher
With disruptions of the gastrocnemius insertion, why do you see knuckling in stance?
stretching of the SDFT over the calcanei from hyper flexion of tarsocrural joint
What signalment for cats have partial disruption of calcaneal tendon?
What is the prognosis?
- cats >5 years
- females outnumbering males 6:1
- Prognosis = good to excellent; cats success rate 84% (72-94%)
What are the breeds seen with luxation of the tendon of SDFT?
Which direction does it go?
What is the treatment?
- Shetland Sheepdogs, collies, Greyhounds
- LATERAL
- desmotomy on side of luxation, repair damaged retaining tissue with 8-10 simple interrupted non-absorbable suture
- immobilize 4 weeks
For arthrodesis of tarsus, what are places to apply plate? Preferred side?
Plantar, dorsal, medial, lateral
plantar = most biomechanically sound BUT dorsal or medial = most common
For dorsal approach to tarsus, cartilage on tibia should be cut at ___ degrees to long axis and ___ degree osteotomy on condylar surface of talus?
90 degrees on tibia
45 degrees on talus
What ancillary treatment can be added to a tarsal arthrodesis plate?
calcaneotibial screw
What is complication rate and outcome of pantarsal arthrodesis?
What is most common complication of medial plating?
complication 30-70%
good outcome 50-70%
medial plate –> plantar necrosis
What are treatment options to arthrodese calcaneoquartal and tarsometatarsal joints?
Outcomes?
cross pins, cross pins & IM pin, ESF, lateral plate
good outcome for both
What are origin / insertion of cranial & caudal cruciate ligaments?
Cranial
- caudomedial aspect of lateral condyle
- insert cranial intercondylar area
Caudal
- lateral surface of medial condyle
- insert medial edge of popliteal notch
What separates the lateral collateral ligament from the lateral meniscus?
popliteus tendon
What is hoop stress?
radial force resisted by tensile stress in circumferentially arranged collagen fibers of tissue
What ligament attaches the body of meniscus to tibia/femur?
coronary
What are the layers of meniscus / alignment of fibers?
surface - random orientation
deeper - innermost 1/3 = radial - deals with compression
deeper - outer 2/3 = circumferential - deals with tension
What is Mow biphasic theory?
mechanical behavior of meniscus under load depends on solid matrix phase & interstitial fluid phase (compressive load carried by fluid)
What are 3 blood supply zones of meniscus?
What % menisci get blood supply?
What blood vessels give the supply?
- Red-red zone (peripheral)
- White-white zone (axial)
- Red-white zone (intermediate)
15-25% of periphery
medial/lateral genicular artery
Under static load, menisci carry ___% load
40-70%
List if taut or loose with flexion/extension?
MCL
LCL
CrCL
CdCL
MCL - taut in flexion, taut in extension
LCL - lax in flexion, taut in extension
CrCL craniomedial band - taut in flexion and extension
CrCL caudolateral band - lax in flexion, taut in extension
CdCL cranial band - taut in flexion, lax in extension
CdCL caudal band - lax in flexion, taut in extension
What is the median flexion/extension angle of the stifle?
Flexion = 41 degrees
Extension = 161 degrees
120 degrees of ROM
Pozzi found (2010) medial meniscal release led to ___ % increase in peak contact pressure & decreased ___ % contact area
140% increase in peak contact pressure
50% decrease in contact area
Pozzi (2010) also found smaller ___% radial width partial meniscectomies had minimal effects. But ___% led to significant effects
<30%
75%
What is the Slocum & Slocum active model?
magnitude of thrust depends on compressive loads and slope of tibial plateau
What is the treatment for avulsion of the CrCL?
Epiphysiodesis – K wire in center of cranial intercondylar area of tibia directed parallel to tibia shaft
What are changes seen with histopath for CrCL?
- loss of fibroblasts from core
- decreased # of typical fusiform & ovoid fibroblasts
- increased # cells undergoing chondroid metaplasia
- decreased birefringence & elongation of crimping
What factors have been implicated with CrCL?
- synovial ab
- breed
- age (<2yr)
- sex = females
- neuter status
- BCS
- TPA conformation
- lack of fitness
What is the reported % rupture of CrCL in contralateral limb?
22-54%
What PE factor has been associated with bilateral CrCL disease?
bilateral stifle effusion
What are differences between postliminary and latent meniscal tears?
Postliminary = after initial procedure (from stable instability)
Latent = present at initial procedure but not identified because of failure of diagnosis at time of surgery
What is sensitivity and specificity of meniscal click?
Sensitivity = 50%
Specificity = 90%
Accuracy = 80%
What is specificity, sensitivity, and accuracy of a stifle with pain on flexion and meniscal click
Sensitivity = 85%
Specificity = 57%
Accuracy = 76%
Probing with arthrotomy ___x more likely to diagnose meniscal tear?
Probing with arthroscopy ___x more likely to diagnose meniscal tear?
2.1-2.6x (arthrotomy)
8x (scope)
Classify the meniscal tears
- Vertical longitudinal tears
- Oblique or flap tears
- Radial tears
- Horizontal tears
- Complex tears
- Degenerative tears
What are the 2 types of medial meniscal release?
Midbody
Caudal (via caudal meniscotibial ligament)
For lateral fabellar suture, what are the methods of tensioning/securing?
Tension
- Square knot
- Sliding knot
- Self-locking
- Tension device
Securing
- Square knot
- Sliding knot + square
- Self-locking + square
- Metallic crimp
What are the best tibial points to be most isometric of femur point on very caudal edge of lateral condyle just next to distal pole of fabella
Adjacent to extensor groove + PL attachment point
What is tightrope Arthrex made of?
Ultra high molecular weight polyethylene polyester
What is the advantage of Swivelock?
secured within blind-ended bone tunnel with interference screw suture anchor – NO knots!!
Also, decreases risks of intra-articular placement
What is the outcome for lateral suture?
good - 87% success rate
What has been associated with increased complication with lateral suture?
- high body weight
- young age with surgery
What are outcomes and complications of fibular head transposition?
69% excellent, another report says 51%, another one less than that…
- fibular fracture, tearing of LCL, post-op instability, seroma
For iota-articular CrCL reconstruction, what are the types of grafts/materials?
Autograft
- bone-patellar tendon-bone
- hamstring – tendon of semitendinosus, gracilis
- quadriceps femoris
Allografts
- all of the above
- Achilles
Synthetics
- dacron
- silk
- ligament augmentation device (LAD)
What is ligamentization?
inflammation from necrosis of fibroblasts due to ischemia causes fibroblasts vein filtration along collagen scaffold & secretion of new collagen during subsequent revascularization
What are the different osteotomy procedures to treat CrCL?
- CCWO
- triple tibial osteotomy
- TPLO
- TTA
- TTA 2
- TTA rapid
- Modified Maquet TTA
- CBLO
- TPLO/CCWO
What are advantages to doing cranial closing wedge?
- doesn’t need special saw
- can be done with open physis
- can decrease TPA to then use for TPLO
- can treat patella alta
- can address angular deformity w/o loss of bone apposition
What has been found to be associated with increased patellar ligament thickening on TPLOs?
- lower post-op TPA (<6 degrees)
- increased BW
What is the reported complication rate for TPLOs?
~7-28%
What are technical errors described for TTA?
- osteotomy fragment too small
- osteotomy cut too low
- not allowing proximal shift of tuberosity with advancement
- malalignment of tuberosity in frontal plane medially
- orienting plate so forks are too far away from loading edge of bone
- orienting plate so after advancement distal end lies caudal to tibial shaft
For TTA, what is re-operation rate?
Overall complication rate?
9.8% re-operation
19-59% complication
For triple tibial osteotomy, what is the wedge angle?
2/3 of angle between PL & line perpendicular to TP slope
WA = 0.6 x CA + 7.3
CA = angle of correction of PTA needed to achieve 90 degrees
List advantages/disadvantages to triple tibial osteotomy?
Advantages
- minimal change to orientation femur-tibial articulating surfaces
- small osteotomy gap
- no loss of limb length
- low technical difficulty
Disadvantages
- additional fixation/metal
- variability of post-op patellar-tendon-TP angle
List anatomic abnormalities associated with MPL (10)
- malalignment quadriceps mechanism
- coxa vara
- femoral varus
- genu varum
- shallow trochlear groove w/ poor developed/absent medial ridge
- hypoplasia of medial femoral condyle
- medial displacement of tibial tuberosity
- internal rotation of tibia relative to femur
- proximal tibial varus
- internal rotation of foot despite distal external tibial torsion
What age do you do trochlea chondroplasty?
<6 months
What % medium dogs have patella luxation? What % are medial?
~81%
Any sex predilection for medium-to-large dogs for patella luxation?
males > females
If torsion > __ degrees, don’t do a DFO to treat MPL
> 27 degrees
What is prognosis for deranged stifle? What are major complications?
good function with reconstruction/stabilization
arthrofibrosis and recurrent instability (most lose 30-40 degrees flexion after successful treatment)
What are classifications of patella fractures?
- non-displaced or minimally displaced
- apical
- basilar
- body
- displaced transverse body
- comminuted
How can you augment/assist repair of patellar ligament rupture?
What is prognosis?
- autogenous fascia lata graft
- transarticular splint
- transarticular ESF
- patellar ligament plating
Px = poor to good
Where in stifle does OC happen?
Prognosis?
axial (medial) part of lateral condyle (96%)
fair to poor, OATS promising
What are most common breeds for stifle OC?
Great Dane, Labrador, Golden Retriever, Newfoundland
For stifle arthrodesis, bone plate must span ___% of both long bones
60-70%
What angle do you place K wires to guide osteotomy for stifle arthrodesis?
90 degrees to long axis then 2 more 20 degrees to each of those
What causes pes varus in tibia? What breed commonly gets it?
eccentric medial closure of distal tibia physis –> slow medial growth
DOXIES