Chapter 82 - Arthrodesis tx Flashcards
What are the indications for arthrodesis of DIP
1.severe osteoarthritis
2.injuries to the collateral ligaments that result in joint instability,
3.luxation of the DIP joint after rupture of the deep digital flexortendon at the level of the distal sesamoid bone
4.chronic intraarticular fractures
5.septic arthritis
dewscribe the Lag technique
Lag technique, shown on a lateralcondylar fracture of the distal MTIII.
(A) The cis-cortexis overdrilled.
(B) The insert drill bit is placed intothe glide hole and advanced past the fracture plane,and the concentric thread hole is drilled across thetrans-cortex.
(C) A depression for the screw headis prepared with the countersink.
(D) The requiredlength of the screw is determined with the depth gauge.
(E) The threads are cut into the thread holewith the tap.
(F) The screw of predetermined lengthis inserted and solidly tightened with the hexagonal tipped screw driver.
What are the surgical approach for DIP joint?
- Dorsal hoof wall approach
- Dorsal approach using plate and screws
- Palmar/Plantar approach
Describe the dorsal hoof wall approach
LAG SCREW technique through a dorsal hoof wall approach, under IVRP
Remove superficial horn with rasp
*5.5mm cortex screws
*LR - uppermost
*The articular cartilage is removed arthroscopicallyusing a 5.5 mm spherical burr through both a dorsal and a palmar/plantar approach (80% can be removed)
*10mm drill bit to do guide holes in hoof wall - 1 axial, 1 dorsolat, 1 dorsomed
*5.5mm glide, up to the distal aspect of middle phalanx dorsodistal-palmaroproximal aimed o the center of distal articular surface
*4.0 mm glide hole all the way
*5.5 hand tap
*5.5mm cortex screwtightened in weight bearing position
*hoof wall defects filled withpolymethyl methacrylate impregnated with 1 g gentamicin sulfate + surface edges sealed with cyanoacrylate
*recovery in a halflimb cast, maintained for 2 months
When is the horse sound and walking?
Complete fusion of the joint and sound at walk takes 8 to 12 months.Techniques Dorsal Hoof Wall Approach
Arhtrodesis of the DIP joint using three parallel 5.5 mm cortex screws placed in lag fashion
Describe the surgical approach of palmar/plantar
*Alternative, more invasive technique *Cartilage scrape throughdorsal open approach
Semicircumferential horizontal skin incision 1cm proximal and parallel to the coronary bandExtended through the common/long digital extensor tendon into the dorsal pouch of the DIP joint
*Through the joint capsule,transecting the collateral ligaments, allowing subluxation of thejoint
- alternative, more invasive technique Transection of DDFT through the dorsal aspectStab incision to the palmaroplantar straight sesamoidean lig and SDFT branches each side to place the 5.5mm Lag Screws
Dorsal incision is closed in 3 layers (extensor tendon, joint capsule, subcut, skin) and the palmar is closed in 2 layers DDFT unable to appositionate - tendon sheath and sucbut in 1 layer followed by skin
Half-limb cast
describe the surgical dorsal approach of DIP using plates and screws
Aiming device with fluoro or CT essential
Articular cartilage removed with 5.5 mm spherical burr through dorsal or palmar approach
2 abaxial 5.5 mm cortex screws are inserted in lag fashion through the dorsal arthro portals across dip joint in a dorsoproximal - palmarodistal direction
2-3 cm long incision dorsal midline just proximnal to the coronary band
extensor tendon is split in the sagittal plane and osteome or plate-passing device is inserted to prepare the plate bade between coronary band and the dorsal aspect of the distal phalanx
Narrow 3-hole 4.5 mm LCP
8 mm drill hole prepared in the dorsal hoof wall
5.0 LHS is inserted routine technique in distal hole
5.5 mm cortex screw is inserted in load position through proximal most plate hole to achieve compression across joint
Middle hole a 5.0 mmm LHS is implanted engaging the distal sesamoid as well.
What are the advantages of the dorsal hoof wall approach over palmar/plantar approach?
minimal soft tissue damage
greater purchase of the screws
much more stable construct.
What is the disadvantage?
disadvantage of both dorsal approaches is associated with the hoof wall holes that have to be prepared and may lead to infection.
How do you approach de DIP joint by arthro?
DR or LR
Joint extension for dorsal and joint flexion for palmar/plantar compartment
The abaxial margins of the common/long digital extensor tendon are key landmarks for arthroscope entry 2 -3 cm proximal to the coronary band and** abaxial to the sagittal midline**
Palmar/plantar landmarks: the proximal margin ofthe collateral cartilage, and the palmar/plantar digital neurovascular bundle 5 mm vertical skin incsiion
What are the indications for arthrodesis for PIP joint?
osteoarthritis (high ringbone),
comminuted fractures of the proxima or middle phalanx,
luxation or subluxation of the PIP joint
What are the PIP techniques?
- Facilitated chemically induced ankylosis
- Laser-assited minimally invasive
- Internal fixation lag tx
- Combination of plate and lag tx
- Dorsal 3-hole narrow DCP or LCP combined with 2 transarticular abaxial 5.5 mm cortex screws
- 2x3.5 mm broad DCP, 5 hole, 4.5 mm narrow DCP plate
Single intraarticular injection of 70% ethanol in the PIP joint of normal horses did not consistently fuse this joint. What is the preferred tx for tx of OA?
Therefore the recommended treatment for osteoarthritis (OA) of the PIP joint remains surgical arthrodesis.
What percentage of horses in the retrospective study experienced complications, including inflammatory reactions and increased lameness, following a single intraarticular injection of 75.5% ethanol in the PIP joints?
12% of horses
What is the median time until horses returned to work after an average of three intraarticular ethanol injections, spaced one month apart, as reported in the study?
The median time until horses returned to work after an average of three intraarticular ethanol injections, spaced one month apart, was 8 months, as reported in the study.
What are the different types of fracture of the middle phalanx?
i) osteochondral chip fractureoriginatingfrom the axial aspect of the palmarproximal border ofthe bon
e; (ii) uniaxialfracture of the medial or lateralpalmar (plantar) eminence;
(iii) biaxialeminencefracture;
(iv) comminutedmiddle phalangeal fracture.
Biaxial eminence fracture of the middle phalanx in hindlimb with plantar luxation of the PIP and distal collape of the proximal phalanx into the fracture line.
Describe the technique of facilitated laser ankylosis
Removal of cartilage usingpercutaneous laser delivery followedby lag screw arthrodesis.
The technique is only suitable forcases with advanced OA +symmetric joint space collapse
Needles are placed in the dorsal and palmar/planter PIP joint pouches and laser energy from a diode laser used to** vaporize** the cartilage and contract the periarticular soft tissues.
Three 5.5 mm cortex screws are then inserted using lag technique through stab incisions,under fluoroscopic or radiographic control
The arthrodesis is accomplished using minimally invasive approaches, and laser‐assisted cartilage removal has been described to reduce postoperative lameness.
describe the surgical approach in the picture
Lateromedial and dorsoplantar 1-year postoperative radiographs of an arthrodesis of the PIP joint using three cortex screws inserted in lag fashion in a foal that was 4 months old at the time of the intervention.
Tx in young foals and demands long time of cast. Use conventional open approach so cas s required
Which is the state of the art technique for arthrodesis of PIP?
Dorsal three hole LCP with two abaxial 5.5 mm transarticular cortex screws placed in lag fashion using open aproach
Describe the approach to the arthrodesis of the PIP
inverted-T skin incision- sagittal vertical incision is extended to the level of the MCP/MTP joint and ends with horizontal incision made 2 cm proximal to the coronary band.
An inverted-V tenotomy of the common/long digital extensor tendon, just distal to the insertion of the extensor branches of the suspensory ligament, allows access to the joint.
The distal part of the tendon is reflected distally, whereas the proximal part is still in its original position.
Incise dorsal PIP joint capsule,** transect collateral ligaments** and joint is disarcticulated.
REmove cartilage with curette.
Osteostixis of both SC bone plates with 5 mm intervals using 2.5 or 3.2 diameter drill bit
Describe the arthrodesis tx of PIP after incision
Contourned the distal aspect of LCP to be weel adapted to the bone surface.
Drill sleeve for 5.0 mm LHS is fastened to the stacked combi-hole (distal hole) and this is placed axially over the proximal aspect of the middle phalanx
With joint open in with good view the **4.3 mm thread hole is drilled **across bone and followed by insertion of **5.5 LHS using power-tapping tx The screw is not tightened
With phalanges in neutral position the transarticular screws location are marked on either side of the plate on the distal aspect of the proximal phalanx
With joint opened drilling of the 5.5 mm glide hole** for the 1st transarticular screw inserted in 1 side of the plate start perpendicular to the bone and gradual redirection to desire oblique direction
Drill is continued until drill bit enter the joint into the palmar/plantar aspect of middle phalanx. **COuntersink
Joint is closed and plate is aligned axially between glide holes
Load drill guide is place in the dynamic compression unit (DCU)** of the proximal combi hole of the plate
Perpendicular 3.2 mm thread hole is prepared across proximal phalanx (tap,depth gauche). Insert monocortical 4.5 mm cortex scrw but not fully tightened on the proximal end of the plate.
The thread hole for one of transarticular screw is drilled,** tapped** and the screw inserted and tightened. The second transarticular is also placed.
Finally the** 5.0 mmm LHS screw** is inserted orthogonally across the bone through the thread part of remaining empty combi-hole and tightened.
Why do you palce a staggered monocortical 4.5 mm cortex screw in the proximal end of the plate?
The rationale for inserting the most proximal screw monocortically is to stagger the stress riser that might arise at the proximal end of the plate between the dorsal and palmar/plantar cortices of the proximal phalanx.
eminence fracture first reduced with lag screw
get the distal end in P2 once in place
Place cortex screw in load position on the proximal plate (pink) monocortical
abaxial transarticular scrws
Slight degree of flexion in the joint and when
Tight P1 load screw (pink)** increases the compression in the joint itself**
Place the other lock screws
what would you do different in this tx in case of heavy warmblood in the arthrodesis of the PIP?
In heavy Warmblood horses additional stability may be achieved by using two additional 5.5-mm screws inserted in lag fashion across the joint
What is the closure and after care considerations?
Closure of the V-plasty of the tendon is accomplished with size USP 1 polydioxanone suture simple continuous
skin is apposed using a combination of size USP 0 polypropylene
Skin staples
Standard distal limb cast that is removed in 2 weeks and after Robert Jones half-limb bnadage
Discharg 3 weeks postop
6 weeks hand grazing
Progressive hand walking on second 6 weeks
First radio control at 3 months postop
Which of the following fracture characteristics differentiate the need for double plate fixation?
a) uniaxial eminence fracture
b) disruption of the palmar/plantar support structures of the PIP joint
c) PIP joint involvement
d) DIP joint involvement
e) none above
b)disruption of the palmar/plantar support structures of the PIP joint
The eminences have to be stabilized lag screw axially (plates abaxial)
So for unstable fracture what is the double plate fixation technique?
You place the** screws AXIAL** in the fragments in lag fashion
the rest is the same with** 2 plates ABAXIAL**
Place the screw proximal to P2 with LHS followed by proximal screws in the plates and you finish your fixation with LHS in the rest of the scrws
What is the technique for minimally invasie application of LCP?
Horses with fairly advanced OA with significant cartilage loss
*Lateromedialand dorsopalmar/-plantar burr with a 5.5-mm drill for adequate cartilage destruction
*The two 5.5-mm transarticularscrews are first placed
*LCP placed with device through small dorsal stab incisions through the tendon
*It has been reported that osseous fusion of the joint with this type of arthrodesis progresses more slowly than that seen with the traditional open technique
*Lameness remains for several weeks, requiring castcoaptation for more than 6 weeks.
In case of comminuted fractures of P2 what do you have to consider?
*implants for surgical arthrodesis is not recommended in the acute stage because of increased risk of a generalized infection of the implants.
Immobilize with cast or transfixation cast with agressive debridement of the joint cancellous bone graft AB sytemic and local
What is the prognosis for PIP joint arthrodesis
*87% returned to intended use with asuccess rate of 81% for forelimb arthrodesis and 95% for hindlimb
What are the types of fracture you can find in P1?
- short incomplete
- long incomplete
- complete uniarticular
- complete biarticular
- dorsal complete biarticular
- palmar/plantar eminence
- multrifragmentary
- transverse body
What is the tx of DOF?
Arthroscopy
Extenson of the MCP joint and distend with fluid 35 mL
The site for the laterally placed arthroscopic portal is in theproximolateral quadrant created by distending the joint maximally, lateral to the common digital extensor tendon
How to approach a short incomplete sagital fracture?
WHERE? sagittal plane
ORIGINATED? in the articular surface of the sagittal groove of P1
CENTERED dorsally but not usually bicortical Many tx conservativly box 2 months and 1 month handwalking
SURGERY reserved for the ones that do not healafter 3 months of conservative
what is the surgical approach for short incomplete sagital fractures? is more on forelimbs or hindlimbs?
FL 94% HL 88%
Insert 3.5 mm or 4.5 mm cortical screws in lag technique in triangular screw configuration
Distal to lateral colateral ligament
FIRST INCISION is proximal to extensor branch of extensor suspensory ligament
SECOND just distal to theextensor branch THIRD in the distal end of the fragment Because of the special cross sectional shape of the boné theproximal screwshould not be exactly inserted in the center of the bone as viewed from aside
Such location would result in excessive compression of the palmar córtex andcouldopen the dorsal córtex.
Therefore the ideal screwplacement is placement slightly dorsal as shown on the redline.
What plate you use for athrodesis of fetlock?
10 hole to 14 hole broadlockingcompressionplate
5.5 mm cortex screws
5.0 mm lockingscrews
1.7 mm cable
Large wire passer
What are the indications for arthrodesis of the fetlock?
- OA
- Severe comminuted complex proximal sesamoid bones
- any major lesion of the suspensory apparatus
describe the surgical approach of LCP placement
Incision over the lateral digital extensor tendon from proximal MC to mid pastern
Elevate all soft tissues as envelpe (extensor tendon, periosteum, joint capsule, collaterals)
Preparation ofjoint surface with curette and multiple osteostixis holes drilled across SCbone with 1 mm deep with 3.2 mm drill
Describe application of tension band
4-mm hole is drilled from lateral to medial atphyseal scar level of MCIII/MTIII and the proximal phalanx, respectively.
Pass the cable 1.7 mm or cerclage 1.25 mm diameter and make a figure 8 with wire or cable passeracross the palmar/plantar aspect of the joint.
Test the angle you want the fetlock to be 10 -15º once you pass the cable through the crimp the cable
Secure the crimping tool and cut the cable off
Describe the application of the plate
Drill 5.5 mm glide holes for transarticular screws before placing the plate on to see the a
Angle one 5.5-mm cortex screw is placed in lag fashion from the dorsal aspect of the distal MCIII or MTIII into each proximal sesamoid bone.
10-14 hole broad 5.5 mm LCP plate is slight bent between 4th and 5th holes about 10 degrees
Align the plate to dorsal surface of P1 and MCIII
1 cortex screw is inserted through the DCU-portion of the combi hole next to the stacked comi-hole and solidly tightened 5.5 mm cortex screw
The two adjacent plate holes (distal in P1) are filled with LHS and attach the plate firmly onto the proximal phalanx
Place a plate tension device in the proximal hole in the MCIII
Start introducing the 5.5 cortex screws to allow the plate to be firmly pressed onto the bone surface in the remaing holes.
Be cautious with the tension band otherwise you will have to restart again
Place the transarticular screws in the glide holes previously prepared 5.5 mm lag fashion
Figure 82-10. Immediate postoperative lateromedial (A) and dorsopalmar (B) radiographs of a PIP joint arthrodesis in a 3-year-old Warmblood horse with traumatic luxation of the PIP joint. The arthrodesis was accomplished with a three-hole narrow 4.5/5.0-mm PIP arthrodesis LCP and two abaxial 5.5-mm cortex screws. The plate used two 5.0-mm LHS and a single unicortical (unicortical to reduce stress concentration in the middle of the bone) 4.5-mm screw in the proximal hole (inserted under load). The two transarticular 5.5-mm cortex screws were inserted in lag fashion to provide plantar compression. The 2-year follow-up lateromedial (C) and dorsopalmar (D) radiographs show complete fusion of the joint, with negligible periarticular new bone formation. (
what happened?
Transarticular screws touched the tension band
What can you add to the plate in the end of arthrodesis of the fetlock?
polymethylacrylate with 5 mL (250mg/ml) amikacine and mix and introduce all over the plate while is liquid next to the plate everywhere but avoid the screw heads.
Do you need a cast for arthrodesis of the fetlock?
No, it is strictly for the soft tissue support specially if swollen. Recovery was done with head and tail rope or pool-raft recovery system
What is the angle over the dorsal joint?
195º angle
Accordingly to Chapman et al VS 2019 what is the prognosis of this tx?
All horses survived to discharge
No complications or infections of implants, only cast sores
Good/Excellent long-term outcomes for pasture and breeding soundness in horses with OA
What can cause worse prognosis according to Chapman et al VS 2019?
Traumatic disruption of the suspensory apparatus is associated with significant soft tissue trauma, including injury to the vasculature of distal limb and reperfusion injury
Ex vivo study of minimally invasive procedures for cartilage removal from MCP or MTP joint and for fetlock tension band application from Farfan et al 2019 used first a distraction screw to create space on the joint. What screw? What drill was used for the cartilage?
5.5 mm cortical screw
4.5 mm drill
Accordingly to Farfan et al 2019 4 stab incisions were performed? How much % of cartilage was removed?
68% for MCP joint
59.5% for the two sesamoid bones
more cartilage removed LATERAL vs medial
What are the surgical indications for arthrodesis of the carpus?
1) Tx of comminuted carpal fractures (salvage for non athletic purpose)
2) Luxations or subluxations
In the case of OA of the CMC joint what tehcnique you can apply with good results (88% return to work)?
Technique1
-4.5 drill bit inserted through four entry points and moved in a fanning fashion
Technique2
- 5.5 drill bit inserted thtough** two entry points** to creat drill tracts
- More even distribution of art damage than technique 1
Technique3
- 4.5 drill bit inserted through two entry points to create three drill tracts
- 1and 2 were more effective
When is indicated each partial or pancarpal arthrodesis?
Partial carpal arthrodesis:
- Distal carpal row is injured and/or one major joint involved OA
- Certain amount of flexion is possible
Pancarpal arthrodesis:
- All 3 joints are fused
- No flexion possible
This horse has severe omminuted fracture of C4 and ulnar carpal, intermediate will get a pancarpal arthrodesis
What is the goal of the partial carpal arthrodesis?
Involves wither fixing the proximal row of carpal bones tothe distal row and MC or fixing the distal row of carpal bones to the MC
What are the plates used in partial arthrodesis?
Various plates can be used LCP prefered
- Choice depends : horse size , availability , surgeonpreference
- 68 holes used
-Recently 4.5 LCP T place is ideal
Describe the surgical technique for partial carpal arthrodesis
- Dorsal or lateral recumbency
- Full flexion
- Carpus approached through 2 vertical skin and subcutaneous incisions on either side of the extensor carpi radialis
Incisions extended through the joint capsule of the affected joint
-** Art. cartilage should be removed **to facilitate fusion with arthroscopy or blindly - Osteotixis+ cancellous bone graft or alternative osteoinductive material are indicated to enhance fusion
- In comminuted carpal bone fractures, interfragmentary screws inserted in lag fashion across large bony fragments improvestability
- Prudent to apply** 2/3 plates across the joints to maintain alignment**
- Also for subluxation with avulsion fractures or bone’s displacement
Preoperative management is important, how should you stability?
Place the horse in Robert Jones from elbow to the fetlock with lateral and plantar splint
How are the plates used for Pancarpal arthrodesis?
Use of broad DCPs or LCPs for comminuted fractures involving both rows and for degenerative carpal joint disease inolder horses
- Purpose of the plates is to stabilize and maintain straigh axis
-5.5/5.0 LCP and dynamic hip screw (DHS) or dynamic condylar screw (DCS) are excelent options stronger than DCP
-Plate luting recommended whe using DCP
Describe the surgical technique for pancarpal arthrodesis
DR - full flexion for destruction of the cartilage
Place the leg in extension with traction to reduce the fracture
Incision of 40 cm vertical skin incision dorsal aspect of the limb centered over the carpus
Make a tunnel under tendon and capsule between ECR and LDE
Use a passer and place the plate in contact with the bone
Use **7 to 8 hole broad LCP **that is introduced slightly dorso lat
Place drill guides in all holes and start
LATERAL plate should be placed as lateral as possible palmarolateral
Place all drill guides at same time and guide with radio your screws positions to place you LHS
Figure 82-19. Lateromedial radiograph depicting pancarpal arthrodesis used to repair a comminuted carpal fracture. A 12-hole broad DCP bone-lengthening plate was applied to the dorsocranial aspect of the limb, and a narrow 12-hole DCP was applied laterally. Cortex screws were used to provide interfragmentary compression across slab fractures.
Figure 82-17. (A) Dorsopalmar, (B) lateromedial, and (C) dorsolateral-palmeromedial radiographs of a second carpal bone fracture in a 2-year-old Warmblood gelding treated by means of partial carpal arthrodesis using two two broad (six- and seven-hole) and one narrow (six-hole) 4.5/5.0-mm LCPs to treat the fracture.
Figure 82-18. (A) Dorsomedial-palmarolateral preoperative radiograph of a multifragment fourth carpal bone fracture in a 7-year-old mare; (B) dorsopalmar radiograph of the partial carpal arthrodesis performed on the horse using two narrow LCPs (six and seven hole) and one LCP T-plate (six hole). (
What is important in the closure of carpal arthrodesis?
facilitate skin closure, several towel clamps can be used to fatigue the skin edges. In extreme cases, a relief skin incision is made at a location distant to the main skin incision, avoiding an area where pressure necrosis may develop under the splint or cast
What is important for the recovery of carpal arthrodesis?
Use a cast for the recovery and after you can place a Robert Jones
Can you perform a minimally invasive approach?
Yes using LCP plate fixation tx for partial and pancarpal joint with good success.
You have to drill the joint surface through stab incisions
What are the major surgical complications?
supporting limb lameness,
incisional infections,
implant infection.
What are the indications for scapulohumeral joint arthrodesis?
Advance OA persistent luxations or subluxations
May treat miniature or small horses breeds to relieve from painfull lameness
Notwell suited for horses
Thereis one report where it was sucessfull in a paint horse w/2 LCPs
What the position of the horse and landmarks of muscles?
**Lateral recumbency **w/ affected limb up
- Curvilinear incision through skin and subcutaneous tissue from midscapula to midhumerous
-Incisionis continued at the
- caudal border of the brachiocephalicus mm
- through the omotransversus to expose biceps tendon
- supraspinous is transected at level of inserion on the GT of humerus
-
suprascapular n. ID
-** biceps tendon transected distal to the supraglenoid tubercle and reflected to expose the shoulder joint. - Joint capsule is incised - curettage
- intermediate tubercle is** removed** with oscillating saw
Describe the placement of the plate in the scapulohumeral joint
- 10 - 12 hole 4.5 DCP or 4.5 LCP
- Contoured to the cranial surface of the scapula and humerus ,** angle of 120º**
- Plateis compressed using two 4.5 cortical screws proximal and distal tothe joint
- One or two plate holes located over the joint should be filled withtransarticular screws in lag
-There maining holes are filled with locking screws
Craniocaudal radiographic view of a SH joint subluxation in a Miniature horse stallion. (B) Lateromedial radiographic view of the SH joint arthrodesis performed in this patient. A 16-hole 3.5-mm LCP was applied to the cranial aspect of the joint region. Over the joint, transarticular screws were implanted through the plate, providing additional stability to the fixation.
What are the tarsus indications for arthrodesis?
- OA of the TMT and DIT unresponsive to medical tx
- Ocasional luxation involving TMT or DIT
-Talocalcanealarthrodesis has been described as a tx fortalocalcaneal OA
What are the described techniques for ankylosis of the tarsus?
Chemical induced ankylosis
Laser-facilitated ankylosis
Transarticular drilling technique
Fixation techniques using T-plate
What are the two agents used to induce ankylosis in the tarsal region?
*monoiodoacetate (MIA) and ethylalcohol.
What is the acton of monoiodoactetate (MIA)?
100 to 250 mg of MIA,a chemical compound that causes cartilage death and stimulates fusion, wasintroduced as a treatment for osteoarthritis of the TMT and DIT joints
What are the complications of this procedure MIA?
severity of discomfort of the horseimmediately after treatment,
postinjection soft tissue swelling,
progression ofosteoarthritis in the PIT joints,
severe soft tissue necrosis that can occurwith extraarticular injection,
variable length of convalescence, andinconsistent outcome
Mechanism of action of the ethyl alcohol
*is through nonselective protein denaturation and cell protoplasm precipitation and dehydration
*neurolytic agent that results in asensory innervation blockade at the intraarticular level *neurolytic properties andnonselective destruction of proteins contribute to its success at disruptingthe cartilaginous matrix, causing necrosis of the chondrocytes and facilitatingarthrodesis
indicate the landmarks for transarticular drilling of distal tarsal joints
*LR expose dorsomedial aspect of the tarsus involved.
*3-cm vertical skinincision is made on the dorsomedial aspect and centeredover the TMT and DIT joints.
*The sites for drill bit entry are midwaybetween a line extending from the groove between the proximal MTII and MTIII,and the most dorsal aspect of the distal tarsus (at the level of the TMT andDIT joints)
ID TMT and DIT with needles and intraop radio
4.5 mm drill bit is passed into the joint space in 3 directions from single entry point on the dorsomedial aspect of the tarsus creating a fan-like pattern
a 20-mm-long tract is directed toward themost lateral palpable extremity of the MTIV;
second, a 20-mm tract angled 30degrees to the first in a plantar direction;
third, a 35-mm tract angled 30degrees to the first in a dorsal direction.
Drilling too deply my lead to what complication?
penetration of the tarsal canal,resulting in unnecessary periosteal reaction or profuse hemorrhage fromdisruption cranial tibial artery
What is the rate of success of this tx?
47-85%
Describe the technique of placement of T plate for arthrodesis
4.5/5.0-mm LCP T-plate over thedorsomedial aspect of the tarsal region
3-cm longitudinal skin incision ismade at the dorsomedial aspect of the distal tarsal join(adjacent to plantar margin of saphenous vein)
medial branch of the tibialis cranialismuscle is then dissected to expose the TMT and the DIT joint
Drill of cartilage of TMT and DIT
Fill the holes with bone graft plug harvested from the proximal tibia or the tuber coxae
Four hole 4.5/5.5 mm LCP T-plate is applied dorsomed through skin incision - minimal contour
screws in the MTIII are inserted through stab incisions
intraop imaging in multiple directions is important for adequate placement of 4.5/5.5 mm LCP T plate
Insert 5.5 mm cortex screw into the central tarsal bone to compress the plate firmly onto bone
Second cortex screw in load position is place through the most distal stacked combi-hole in the plate into MTIII
Remaining plate holes are filled with LHs
What are the considerations postoperativly?
*Postoperatively, the limb is keptunder a bandage for 2 to 3 weeks.
*Lameness can persist for severalmonths *Rehabilitation must be conductedgradually over several months.
In case of luxation of the distal tarsal joints where should you place the palte?
Plantarolateral plate application
Where is the skin incision for the plate insertion?
*skin incision extends from the topof the calcaneus to the mid-MTIII on the plantarolateralaspect.
*subcutaneous tissues are separatedto expose the bone and the luxated joint
Asmuch cartilage as possible is removed from the affected joint using a curette
What is the surgical tx for plate insertion?
Cartilage removed from affected joint
Then the luxation is reduced andthe head of the MTIV is trimmed with a chise
OR alternative approach involvesremoving the entire MTIV.
*appropriate plate spans the area ofinstability and extends from the proximal calcaneus to the midmetatarsalregion
Depending on the size of the horse, thisis typically a 9- to 16-hole broad DCP or LCP platecontoured to the bones
*plate is fixed with two corticalscrews using the dynamic properties of the plate to compress the area ofinstability
*At this stage, the unaffecteddistal tarsal joints are drilled focally (as described earlier) to encourage transarticularnew bone formation
*remaining screw holes are filledwith 5.5-mm cortex screws or LHSs respectively
*Solid purchase of each screw in healthybone and engaging both corticals isof great importance with this fixation.
*If possible, several oblique transarticularscrews are inserted across the luxated joint to provide additional stabilityand support across the major portion of affected joint
*In locations that requiresubstantial screw angulation through the plate, 4.5-mm screws may be used.
*For luxationsof the distal tarsal joints with dorsomedial instability, a 4.5/5.0-mm LCPT-plate is applied to the medial or dorsomedial aspect of the distal tarsus
What is the postoperative considerations?
FULL LIMB cast applied for 2 weeks period and after Robert Jones for 2-3 additional weeks
When do you start hand walking and light riding?
Handwalk 2 months
Light work 3 months
(A) Craniocaudal radiographic view of a TMT luxation in a pony. (B) Oblique postoperative radiographic view of the tarsal region after application of a nine-hole narrow 4.5/5.0-mm LCP to the plantarolateral aspect of the calcaneus and proximal MTIII region.
Figure 82-22. Graphic illustration of the drilling technique for tarsal arthrodesis. The sites for drill bit entry are midway between a line extending from the groove between the proximal MTII and MTIII, and the most dorsal aspect of the distal tarsus (at the level of the TMT joint and DIT joint). Three diverging drill holes are made along the articular surfaces of the distal tarsal joints using intraoperative imaging.
Figure 82-23. Graphic illustration of a tarsal arthrodesis with a four-hole 4.5/5.0-mm LCP T-plate applied dorsomedially.
Figure 82-24. Minimally invasive approach for placement of a 4.5/5.0-mm four-hole LCP T-plate. Intraoperative regional perfusion of antimicrobials can be performed in an attempt to reduce the risk for postoperative infection in distal tarsal joint arthrodesis.
Figure 82-25. Intraoperative imaging is important for optimal placement of a four-hole 4.5/5.0-mm LCP T-plate to the dorsomedial aspect of the DIT joints. The plate is contoured to the bone to facilitate skin closure. (A) DLPMO view shows the contouring of the plate and the position of the screw holes; (B) DMPLO view is required to adjust the position of the T-bar in relation to the joint space of the PIT joint.
Figure 82-27. (A) Lateromedial, (B) dorsomedial-
plantarolateral, (C) dorsolateral-plantaromedial, and (D) dorsoplantar radiographs of an arthrodesis of the distal tarsal joints using a four-hole 4.5/5.0-mm LCP T-plate in a 7-year-old Warmblood mare with chronic lameness because of severe osteoarthritis.
Figure 82-26. (A) Intraoperative DLPMO view of the 4.5/5.0-mm LCP T-plate at the dorsomedial aspect of the distal tarsal joints. Tension across the DIT joints and the TMT joint is achieved by inserting a second cortex screw in loading position in the MTIII. (B) A cortex screw is being inserted across the DIT joints to counteract rotational forces.
Figure 82-28. (A) Intraoperative DMPLO radiographic view of a 560-kg Warmblood stallion with a plantar instability in the DIT joint. A 12-hole broad DCP is contoured to the bone and two 4.5-mm cortex screws are applied using the dynamic compression properties of the plate to compress the DIT joint. (B) Stable fixation is achieved using six screws proximal and six screws distal to the subluxated DIT joint. The horse made an uneventful recovery and could be used as a breeding stallion.
Figure 82-29. (A) Craniocaudal radiographic view of a TMT luxation in a pony. (B) Oblique postoperative radiographic view of the tarsal region after application of a nine-hole narrow 4.5/5.0-mm LCP to the plantarolateral aspect of the calcaneus and proximal MTIII region.
Figure 82-30. Oblique postoperative radiographic view of a talocalcaneal arthrodesis performed through three converging 5.5-mm cortex screws inserted in lag fashion across the lateral facet of the talocalcaneal joint. Washers were used in the two proximal screws to increase the contact area of the implants and reduce stress concentration at the bone–screw head junction.
Talocalcaneal arthrodesis you prepared the limb how for surgery?
LR with affected limb uppermost
Describe the surgical technique for talocalcaneal arthrodesis
lateral aspect of the calcaneus** aslightly **curved incisio**n is made from the m**idpoint of the bone to its distal end**
tissues are sharply divided down tothe bone.
** *Needle markers** are used to determine the **correct angulation **of the future screws under **fluoroscopic guidance**
**drill bit** is** aimed** toward the **plantaromedial **aspect of the **medial trochlear** **ridge of the talus**, avoiding penetration of the **tarsocrural joint** at the **intertrochlear groove.**
**Two or three 5.5-mm cortex screws areinserted in** lag fashion** across the lateral facet using routine technique
What are the complications of this surgery for the talocalcaneal?
Complications of arthrodesis include:
postoperative infection,
implantfailure,
laminitis in the opposite limb,
long-term lameness,
development ofangular limb deformities
*Accidental insertion of bone screwsinto a joint space can provide a continuous source of pain and should beavoided
What can you add to avoid weakening of the calcaneal bone?
Washers
