Chapter 99 - Tarsus Flashcards
Which ligament maintains the two bones of the tarsus in close proximity in the talocalcaneal joint?
Intertarsal ligaments
Which joint of the tarsus is mainly responsible for its movement during ambulation and weight bearing?
Tarsocrural
For diagnostic and therapeutic purposes, which joints are often injected in the tarsus?
TMT and DIT
What is the special relationship of the facets in the talocalcaneal joint that prevents motion?
they have strong interosseous ligament
Which tendon spans the entire dorsal tarsal region and is maintained by retinacula?
LDE
What forms the cranial part of the reciprocal apparatus in the tarsus?
Fibularis (Peroneus) tertius tendon
What bursa is located between the superficial digital flexor and the gastrocnemius tendon proximally and distally?
Intertendinous calcaneal bursa
What is the function of the tarsus in weight bearing?
To transform axial loading into oblique forces
Where does the tendon of the medial digital flexor muscle traverse within the tarsal region?
Medially
What ensures that when one of the major joints of the rear limb is flexed, all others flex?
Intact reciprocal apparatus
Which joints show communication after injections in the tarsus, potentially affecting medication effects?
Distal intertarsal and tarsometatarsa
What percentage of joints showed communication between the TMT and DIT joints in a study?
38%
What are the joints most affected by OA?
TMT and DIT
vWhat are the poor conformations that predispose to OA?
Bowlegged and sickle-hocked conformation
Dysmature foals with crushing of central and 3rd metatarsal bone
What is the most common clinical sign of OA in TMT and DIT?
Lameness + toe dragging + short cranial phase of the stride
How to perform the diagnosis?
Lameness work up and many times:
*Lameness can be excerbated with inside limb in tight circles
*Flexion tests often positive
*Check shoes for uneven wear
What are the radiographic findings in OA of hock?
Common findings:
Periarticular enthesophytes
Periosteal new bone formation
*Subchondral bone lysis and/or sclerosisDecreased corticomedullary demarcationNarrowing or loss of joint space
*Spur at 3rd metatarsal bone is frequent
*Early changes occur
The medial and lateral collateral ligaments of the tarsus each consist of two
ligaments:
long and a short ligament.
what are the connections of long collateral ligament
long collateral ligaments
connect the distal tibia to the proximal metatarsal region,
but they also have attachments to the talus and small tarsal
bones
what are the connections of short collateral ligament
short collateral ligament consists of a superficial,
middle, and deep part and originates from the medial or lateral
malleolus, respectively, cranial to the origin of the long collateral
ligaments, and attaches to the talus and calcaneus
short collateral ligaments are tense in
flexion and loose in extension
The tarsus is composed of five joints, name them
the tarsocrural (TC),
proximal intertarsal (PIT), distal intertarsal (DIT), tarsometatarsal
(TMT), and talocalcaneal (TCa) joints
How many joints of tarsus are immobile?
4
In a study the communication btw TMT and DIT was %, TMT % DIT and PIT with % had communication btw DIT joint and tarsal canal
100% TMT and DIT
DIT and PIT 2%
14% DIT and tarsal canal
The fibularis tertius tendon is penetrated by the tendon of the
tibialis cranialis muscle, which then divides into three branches, the medial, middle, and lateral branches, before inserting on the central, third, and fourth tarsal bones as well as the proximal metatarsal region
medial branch is better known as the
cunean tendon, which at one time was thought to be responsible for the development of spavin
The gastrocnemius muscle and tendon form the
caudal part
The superficial digital flexor tendon is attached to the abaxial aspects of the calcaneus via the medial and lateral retinacula and continues distad to the
digit
voluminous intertendinous calcaneal bursa is located between the superficial digital flexor and the
gastrocnemius tendon proximally, and between the superficial digital flexor tendon and the long plantar ligament distally.
What are the treatments for distal intertarsal joints (medical and sx)?
1) Corrective shoeing - wider outside branch
2) Extracorporeal shcokwave therapy (middle high energetic 0.2-0.4 mJ/mm2) 2 to 3 s every 3 w
3) Medical management with steroids, anti-inflammatories
4) surgical management
4.1 Cunenan tenectomy
4.2 Wamberg technique
4.3 Laser facilitated ankylosis
4.4 Arthrodesis with drilling
4.5 Arthrodesis with LCP T plate
4.6 Ethanol injection
What does corrective shoe do to the medial patellar ligament and medial side of the tarsal joint? MT?
Aleviates tension to the medial patellar and tarsal joint
Increases pressure of MTP
A - subcutaneous bursa
B - intertendinous bursa
C- gastrocnemius bursa
Dorsoplantar flexed view - skyline
Figure 99-14. Graphic illustration of the arthroscope portal site for examining the plantar pouch and visualizing the plantar aspect of the trochlear ridges of the distal tibia. The arthroscope is placed contralateral, and the instrument is placed ipsilateral to the lesion. a, Long digital extensor tendon; b, lateral digital extensor tendon; c, deep digital flexor tendon.
Figure 99-1. Graphic illustration of a lateral (A), dorsoplantar (B),
plantarodorsal (C), and medial (D) view showing the anatomic structures
associated with the tarsal region. a, Distal tibia; b, talus; c, calcaneus; d,
third metatarsus (MTIII); e, MTIV; f, long digital extensor muscle and
tendon; g, lateral digital extensor tendon; h, lateral digital flexor muscle
(together with “v” form the deep digital flexor tendon); i, soleus tendon;
j, Achilles tendon; k, superficial digital flexor tendon; l, short lateral collateral
ligament; m, long lateral collateral ligament; n, plantar ligament; o, long
part of the medial collateral ligament; p, medial part of the tibialis anterior
tendon (cunean tendon); q, middle part of the tibialis cranialis tendon;
r, branch of the fibularis tertius tendon; s, medial digital flexor tendon;
t, medial plantar ligament between the talus and calcaneus; u, short part
of the medial collateral ligament; v, tendon of the tibialis caudalis muscle;
w, fibularis tertius muscle; x, main branch of the fibularis tertius tendon.
Figure 99-1. Graphic illustration of a lateral (A), dorsoplantar (B),
plantarodorsal (C), and medial (D) view showing the anatomic structures
associated with the tarsal region. a, Distal tibia; b, talus; c, calcaneus; d,
third metatarsus (MTIII); e, MTIV; f, long digital extensor muscle and
tendon; g, lateral digital extensor tendon; h, lateral digital flexor muscle
(together with “v” form the deep digital flexor tendon); i, soleus tendon;
j, Achilles tendon; k, superficial digital flexor tendon; l, short lateral collateral
ligament; m, long lateral collateral ligament; n, plantar ligament; o, long
part of the medial collateral ligament; p, medial part of the tibialis anterior
tendon (cunean tendon); q, middle part of the tibialis cranialis tendon;
r, branch of the fibularis tertius tendon; s, medial digital flexor tendon;
t, medial plantar ligament between the talus and calcaneus; u, short part
of the medial collateral ligament; v, tendon of the tibialis caudalis muscle;
w, fibularis tertius muscle; x, main branch of the fibularis tertius tendon.
Figure 99-3. Graphic illustration of the injection site for the distal intertarsal (DIT) joint. The DIT joint is injected medially in the proximal aspect of the space that exists between the central tarsal bone (e), third tarsal bone (d), and fused first and second tarsal bone (c). The entrance to this space can often be felt with firm palpation and is found at the distal border of the cunean tendon (a), approximately 2 cm caudal to a vertical line extending distad from the medial malleolus. The location for needle entry can also be located along a line between the distal tubercle of the talus (b) and the palpable space between the second metatarsus (MTII) (f) and MTIII, where it intersects the cunean tendon.
Figure 99-2. Marked enlargement at the dorsomedial aspect of the distal tarsal region (arrows) in a horse suffering from osteoarthritis of the distal two tarsal joints (bone spavin). Excessive new bone formation is responsible for this appearance.
Figure 99-5. DLPMO radiographic view of the tarsus. There is an advance stage of ankyloses in the TMT and the DIT joints. The needle is inserted in the TMT joint.
Figure 99-5. DLPMO radiographic view of the tarsus. There is an advance stage of ankyloses in the TMT and the DIT joints. The needle is inserted in the TMT joint.
Figure 99-4. DLPMO radiographic view of the distal tarsal joints showing periosteal new bone formation, subchondral bone lysis and sclerosis, reduced corticomedullary definition, and narrowing or loss of the joint space.
Figure 99-6. Lateromedial radiographic view of the tarsal region of a 2-month-old foal that was born with incomplete ossification. The central tarsal bone is partially collapsed dorsally. This foal is at high risk to develop juvenile osteoarthritis.
Figure 7.23(b) Dorsoplantar (fl exed) view of the same hock
as Figure 7.23a. Lateral is to the right. Note the irregular
contour of the surface of the sustentaculum tali (arrow) over
which the deep digital fl exor tendon passes, and the poorly
defi ned opacities in the soft tissues medial to the calcaneus.
Figure 7.23(a) Plantarolateral-dorsomedial oblique view of a
hock. There is considerable modelling of the sustentaculum
tali (arrow) which was associated with distension of the tarsal sheath and severe lameness.
Figure 99-7. Positive contrast arthrogram after injection into the TMT joint, showing communication of the tarsometatarsal joint with the proximal intertarsal and tarsocrural joints and the extensor digital sheath
Describe cunean tenectomy
Under sedation + local anesthesia
▫Decreases rotational forces on the tarsus that occur when cunean tendon tightens (obliquely)▫V shape line block from chestnut to saphenous v.
▫4 cm vertical skin incision over tendon5 cm dorsal to chestnut
▫4cm tendon removed w/ n.15 scalpel bladeskin sutured
▫Compression bandage
▫Sutures removed 14th day
Usually performed with LCP T plates
Stall rest 12 days + limited hand walkingWalking increased after suture removal3weridingFull work at 6 wks
Describe Wamberg technique
Complements cunean tenotomy
▫Grid like incisions over medial aspect of the tarsus down to bone
▫Performed ar 3.5 mm intervals▫
Completes neurectomy of this region ▫Abandoned technique
Driiling ankylosis mention the landmarks. Be specific
Neodymium:yttrium aluminum garnet or (Nd :YAG) or diode laser
LR with acess to medial side or DR if bilateral
After routine preparation of the surgical site, a 3-cm vertical skin incision is made on the dorsomedial aspect and centered over the TMT and DIT joints. 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 and DIT joints) (Figure 82-22). This is adjacent to the plantar margin of the saphenous vein, which has to be displaced dorsally to avoid iatrogenic trauma. Placement of a Penrose drain around the vein facilitates its manipulation during the surgical procedure. The TMT and DIT joints** are identified with hypodermic needles using intraoperative radiographs or fluoroscopy.
A 4.5-mm drill bit is passed into the joint space in three directions from a single entry point on the dorsomedial aspect of the tarsus, creating a fan-like pattern of holes. The tracts are best drilled in pairs (TMT and DIT): first, a 20-mm-long tract is directed toward the most lateral palpable extremity of the MTIV; second, a 20-mm tract angled 30 degrees to the first in a plantar direction; and third, a 35-mm tract angled 30 degrees to the first in a dorsal direction. For intraoperative imaging, it is important to orient the x-ray beam perpendicular** to the drill tract and to angle as necessary in a distal-to-proximal direction to bring the joint margins into convergence. The number of images can be reduced if two drill bits are used and tracts in the TMT and DIT joints are imaged simultaneously.
Is the cunena tenectomy good?
cunean tenectomy has been debated, but there are no controlled clinical studies or experimental evidence in the literature (83% improvement by owners). Today, cunean tenectomy as a sole procedure is rarely performed. It is, however, performed together with an arthrodesis using locking compression plate (LCP) T-plates (see later and Chapter 82).
what is the theory behind the laser technique for arthrodesis?
The theory behind this technique is that by superheating and vaporizing synovial fluid, chondrocyte death should follow
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.
was the average destruction of joint surface with drilling in %?
The average destruction of joint surface was 18.0% (14.5%–23.8%) for the proximal MTIII and 21.7% (15.1%–30.4%) for the proximal third tarsal bone, respectively
what you have to be careful when drilling the DIT and TMT?
Drilling too deeply may lead to penetration of the tarsal canal, resulting in unnecessary periosteal reaction or profuse hemorrhage from disruption of the perforating branch of the cranial tibial artery
Hoaglund et al, 2019 Comparing the clinical success rate of dorsolateral approach to the medial approach for injection of the centrodistal joint in the horse concluded that a high percentage of injections end up perivascular. What %?
65% resulted in extensive perivascular subcutaneous contrast deposition after infiltration into tarsal canal. Dorsalt approach was equivalent to teh medial approach when tradional tx
Radiographic guidance improves medial approach but not lateral approach
US assisted injection of the centrodistal joint in the horse by Samson and Russell EVJ 2020 what was the accuracy injecting?
Had 70% of accuracy injecting
Name the medication you could administer in the joints
Triamcinolone acetatehigh motion joints , VS. methyl prednisolone acetate low motion joints
*44% used 18 - 40 mg of triamcinolone acetate as the total body dosage
*Hyaluronan & polysulfated glycosaminoglycan (PSGAG; Adequan ) are used to improve joint environment and reduce inflammation in high motion joints
*Although hyaluronan was frequently combined with corticosteroids, PSGAGs were primarily injected IV not that effective (compared to steroids)
You should be careful during the drilling preparation by placing a penrose why?
- CAUTION: adjacent to the plantar margin of the saphenous vein . The latter has to be displaced dorsally to avoid trauma - Placementof a Penrose drain
What is the prognosis for surgical arthrodesis?
Favorable
REturn in 66-85% for DIT and TMT
What is the mechanism of action of ethyl alcohol?
Mechanism of action through nonselective protein denaturation and cellcytoplasm precipitation and dehydration
- Neurolytic results in a sensory innervation blockade at the intraarticular level
- Disrupts cartilage matrix , causes necrosis of chondrocytes and facilitates arthrodesis
Prognosis for ethanol injection
50% normal horses injected w 70% ethanol and radio fusion in 4mo is 94%
After surgical ankylosis of TMT and DIT joints the horses are free of lameness in how much time?
In 3 to 4 months
What is the postoperative treatment following arthrodesis of the TMT and DIT joints
Hand walking exercise is started 3 to 4 weeks after surgery. Administratration of AINS and AB
OA of talocalcaneal joint the clinical signs are not specific, waht are the best methods for diagnosis?
Radio and scintigraphy
When do you judge if the TMT and DIT ankylosis worked?
12 months after procedure
what is the prognosis for undergoing arthrodesis of the DIT and TMT joints? does PIT have influence?
66.7% to 85% of horses undergoing arthrodesis of the DIT and TMT joints.
Yes PIT worsens the prognosis due to communication with TC joint
Injection with MIA what is the prognosis?
The prognosis following chemical fusion of the distal tarsal joints with MIA is favorable.
When do you judge the horses with MIA tx?
Some horses show dramatic improvement in the original level of lameness within 1 week after treatment, even though fusion might not be apparent radiographically for 3 to 6 months
What is the % of success of MIA tx of the distal tarsal joints?
100%)horses had radiographic fusion of the treated distal tarsal joints, and 12 of 16 75% were free of lameness and the treatment was considered successful
describe in detail the surgical placement of T - plate for arthrodesis
A 3-cm longitudinal skin incision is made at the dorsomedial aspect of the distal tarsal joints, which is consistently adjacent to the plantar margin of the saphenous vein. Use Penrose drain to deviate the vein.The medial branch of the tibialis cranialis muscle is then** dissected to expose the TMT and the DIT joint.** Any exuberant exostoses are partially removed with an osteotome and mallet. This facilitates identification of the joint spaces involved, provides a greater plate-bone contact area, and reduces the amount of plate contouring needed. The **PIT joint space is identified through placement of two hypodermic needles or two 2-mm drill bits using intraoperative imaging technique.
Cartilage of the TMT and the DIT joint is partially removed using the drilling technique described previously. These holes may be filled with a bone graft plug harvested from the proximal tibia or the tuber coxae. Placement of such a plug, hydroxyapatite granules, or biodegradable bone cement will enhance osseous union of the two articulations by means of spot welds.
The selected four-hole 4.5/5.0-mm LCP T-plate is applied dorsomedially through the skin incision. Minimal contouring is usually required. The T-plate is placed minimally invasively by pushing it distally between the skin and the dorsomedial aspect of MTIII. The screws in the MTIII are inserted through stab incisions** (Figure 82-24).
Intraoperative imaging in multiple projections is important for adequate placement of the 4.5/5.0-mm LCP T-plate (Figure 82-25). The thread hole for the** central hole** of the horizontal bar of the T-plate is drilled with the 4.0-mm drill bit protected by the corresponding drill sleeve within the body of the central tarsal bone, parallel to the joint surfaces. In smaller horses, 4.5-mm screws may be used instead of 5.5-mm screws. In that case, a 3.2-mm thread hole is prepared. (It is important to use 5.5-mm cortex screws whenever possible, because they resist cyclic loading better than 4.5-mm screws. Screws 4.5 mm in diameter often fail in an adult horse.)
After tapping the thread hole, the 5.5-mm cortex screw is inserted into the central tarsal bone and tightened to compress the plate firmly onto the bone. At this point, limited adjustment of the T-plate is still possible to align the T-bar parallel to the proximal intertarsal joint. Compression across the DIT and TMT joint is achieved by inserting a **second cortex screw **in load position through the **most distal stacked combi-hole in the plate into the MTIII **(Figure 82-26, A). If the DIT and TMT joints are to be fused, screws are inserted next to the T-plate across the TMT joint or across the DIT joint, respectively. The remaining plate holes in horizontal and vertical bars are filled with LHSs (Figure 82-27). It is possible to use two LHSs in the horizontal bar and two in the vertical bar to save some cost by using cortex screws in the remaining holes.
After **flushing the surgical site, **the subcutaneous tissues and the skin are closed in routine fashion. Intraoperative regional perfusion of antimicrobials is recommended.111 The surgical site is covered with a bandage.
what is the postoperative care of arthrodesis of TMT and DIT with T plate?
kept under a bandage for 2 to 3 weeks. The skin sutures or staples are removed 10 days after the surgery. Lameness can persist for several months. Rehabilitation must be conducted gradually over several months.
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 82-26. (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 82-27. (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 82-27. (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.
Conservative therapy of OA talocalcaneal joint is an option?
Unrewarding
describe the ligaments of TCa joint
Ligaments of talocalcaneal zone:
1. medial,
2. lateral,
3. proximal,
4. interosseous talocalcaneal
What are the surgical treatment of OA talocalcaneal?
Partial tibial and fibular neurectomy not recommended – poor results
▫Osteotixis also doesn’t improve
▫Arthrodesis of TCa - 3 techniques
Neurectomy of fibular and tibial nerves for TCa is an option?
No. Surgical treatment involving partial tibial and fibular neurectomy cannot be recommended because of the poor results
Conservative tx of TCa is an option? What are the tx?
Conservative therapy is usually unrewarding. Stall rest, pasture exercise, and intraarticular corticosteroids with or without hyaluronan or PSGAG did not bring about consistent improvement of the lameness.
Figure 99-9. Scintigraphic images (A–C) and lateromedial radiograph (D) of a horse with 3/5 lameness right hind. There is a marked radiopharmaceutical uptake in the area of the talocalcaneal joint of the right hindlimb. LM radiograph view of osteoarthritic changes located in the talocalcaneal joint (arrows).
Figure 99-9. Scintigraphic images (A–C) and lateromedial radiograph (D) of a horse with 3/5 lameness right hind. There is a marked radiopharmaceutical uptake in the area of the talocalcaneal joint of the right hindlimb. LM radiograph view of osteoarthritic changes located in the talocalcaneal joint (arrows).
Describe the surgical technique for TCa arthrodesis
GA - LR - affected limb uppermost - tourniquet optional
At the lateral aspect of the calcaneus a slightly curved incision is made from the midpoint of the bone to its distal end. The tissues are sharply divided down to the bone.
Needle markers are used to determine the correct angulation of the future screws under fluoroscopic guidance. Computer-assisted guidance greatly facilitates preparation of the drill holes (see Chapter 13). The 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 are inserted in lag fashion across the lateral facet using routine technique (Figure 82-30). There is an adequate amount of solid bone present to achieve stable transarticular compression. By slightly diverging the direction of the screws, an increased compressive effect can be achieved. To prevent weakening of the calcaneal bone, **washers **may be applied, which negate the need for countersinking. Alternatively, the screws may be inserted through a plate contoured to the calcaneal surface. Once the screws are in place and solidly tightened, the incision is closed using routine
technique.
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.
Figure 7-27 A, Dorsoplantar radiograph showing large and smaller intraarticular fractures of the lateral malleolus of
the tibia. B, External view of position of arthroscope and instrument to remove fragmentation of the lateral malleolus
of tibia.
Figure 99-10. Lateromedial radiograph showing a large fracture fragment including the distal intermediate ridge of the tibia (A). This fracture was fixed with two cortical lag screws across the fracture
plain (B).
Figure 99-11. Dorsoplantar (A) and lateromedial (B) radiograph of a large fracture fragment in the distal tibia including the medial malleolus. Arthroscopy of the tarsocrural joint shows the displacement of the fracture in the distal tibia (C). Fixation was achieved with two cortical lag screws and a LCP plate using 4.5- and 5.5-mm cortical screws (D, E)
Figure 99-11. Dorsoplantar (A) and dorsolateral plantaromedial oblique (B) radiographThe three most distal screws of the plate were inserted in lag fashion. Reduction of the fracture is visualized arthroscopically (F).
Figure 99-12. (A) A large, slightly displaced slab fracture of the lateral trochlear ridge. (B) The fracture was repaired with three 3.5-mm cortex screws inserted perpendicular to the fracture plane. The screws were inserted from the articular surface, and the screw heads were countersunk below the surface.
(C) A 2-year follow-up revealed no osteoarthritis in the joint. The horse was successfully competing in show jumping events.
Figure 7-18 Diagram of position of arthroscope and instrument
during operations involving an osteochondritis dissecans lesion
of the medial trochlear ridge using arthroscopic and instrument
approaches from the same side of the joint. LDE, Long digital
extensor tendon; PT, peroneus tertius; TC, tibialis cranialis.
Figure 7-14 Larger osteochondritis dissecans (OCD) lesion of lateral trochlear ridge (LTR) of the talus. A, Radiograph
showing fragmentation at distal aspect and defect extending 3 cm up LTR. B, Arthroscopic view of OCD flap
delineated by cleft that probe is in. C, Use of probe to separate OCD flap and define limits. D, After removal of flap
evaluating defective tissue underneath. E, After debridement of osteochondrotic tissue down to healthy, bleeding bone
and smooth edges of cartilage, which is still attached to the bone.
Figure 99-13. Lateromedial radiographic view showing a teardrop lesion or fragmentation originating from the distal aspect of the distal medial trochlear ridge of the talus. This finding is usually incidental and rarely has any clinical significance.
Figure 7-29 A, A skyline radiograph of the tarsus showing a fracture of the proximal plantar aspect of the medial trochlear
ridge (arrow) in a 2-year-old Percheron-cross filly. The fracture resulted from a kick 2 months before radiography. B, An
oblique flexed lateral radiograph projects the proximoplantar extent of the medial trochlear ridge and the fracture (arrow).
Figure 99-15. (A) Avulsion fracture of the lateral aspect of the distal talus with PIT articular involvement. The horse was managed conservatively with rest for 1 year and eventually fracture repair with 3.5 mm cortex screws after
Figure 99-15. (A) Avulsion fracture of the lateral aspect of the distal talus with PIT articular involvement. The horse was managed conservatively with rest for 1 year. (B) Marked joint distention visible in the TC and PIT joints. a, Dorsomedial pouch; b, plantarolateral pouch; c, lateral aspect of the proximal intertarsal joint. (C) Postoperative radiographic view showing the fixation of the fracture with two 3.5-mm cortex screws. Six months later, the horse competed successfully in show jumping events.
Figure 99-15. (A) Avulsion fracture of the lateral aspect of the distal talus with PIT articular involvement. The horse was managed conservatively with rest for 1 year. (B) Marked joint distention visible in the TC and PIT joints. a, Dorsomedial pouch; b, plantarolateral pouch; c, lateral aspect of the proximal intertarsal joint. (C) Postoperative radiographic view showing the fixation of the fracture with two 3.5-mm cortex screws. Six months later, the horse competed successfully in show jumping events.
Figure 99-17. DLPMO radiographic view of the tarsal region of a foal (100 kg bodyweight) with a transverse fracture of the calcaneus (A).
Figure 99-17. DLPMO radiographic view of the tarsal region of a foal (100 kg bodyweight) with a transverse fracture of the calcaneus (A). The fracture was reduced and fixed with a lag screw across the fracture plane. Subsequently, a 6-hole LCP plate with locking screws was applied plantarolaterally (B). The foal made an uneventful recovery and the fracture healed.
Describe how would go and remove this fragment
Plantar pouch of TC
The plantar pouch is excellent to visualize also the L and M trochlear ridges not visualized by dorsal approach
*Joint distention is critical ** & can be performed dorsally or by placing a needle in center of plantar pouch
*Skin portal is made in center of plantar outpouching with tarsus flexed at 90 degrees
Introduction of scope through a plantaro medial/plantarolateral portal **puts scope immediately **dorsal to tarsal synovial sheath surrounding DDFT & plantar to trochlea rridges **of talus Evaluation of plantar aspects of medial & lateral trochlear ridges of talus, trochlear groove,distal tibia (plantar aspect of intermediate ridge), articular portion of tendon sheath containing DDFT
Extending joint to approx 120 degrees - medial & lateral dorsalcul-de-sacs of joint can be observed more easily
More flexion an enhanced examination of proximal areas of medial & lateral trochlear ridges is possible
Diagram of arthroscopic field A and arthro view B of the plantar pouches of the right TC joint using plantarolateral entry
With the horse in DR the IRT is uppermost and the LTR and MTR are visible. An egress canula has been insterd in the plantaromedial cul-de-sa of the joint and used to caudally retract the DDP within the tarsal sheath
What if you have ti remove a fragment from the medial malleolus of the tibia?
Medialmalleolus
*Dorsomedial portal as DIRT but mademore distal
▫To minimize risk of pulling the arthroscope out of the joint during visualisationInstrument portal slightly axial and distal
Fig 2: Transverse computed tomography image (bone window) of the left tarsus
of Case 1, illustrating a typical fracture configuration. Dorsal is on top, medial on
the right. A fracture line (black arrow) is running in the sagittal plane through the
central tarsal bone (os tarsi centrale; OTC). This line exits the plantar cortex in
the indentation (white arrow) between the articular surface to the fused first and
second tarsal bone (I + II) and the articular surface to the fourth tarsal bone (IV).
Note the marked sclerosis of the central tarsal bone around the fracture line,
especially in the dorsal aspect.
Figure 29.20 A two-year-
old
Thoroughbred with acute onset lameness after racing. It presented five days after injury, and there was
moderate distension of the tarsocrural joint. (a) DM-PLO
radiograph demonstrating a slab fracture of the dorsolateral aspect of the central
tarsal bone. (b) Transverse CT image demonstrating fracture configuration. (c) Intra-operative
DM-PLO
radiograph with needle placement to
guide repair. (d) Intra-operative
DM-PLO
radiograph following screw placement. (e) DM-PLO
radiograph 10-months
post-operatively
demonstrating fracture healing. The colt first raced five months post-operatively
and subsequently seven times with three wins and one place.
Fig 4: Dorsomedial-plantarolateral oblique radiograph of the right tarsus of Case
5 obtained 14 months after surgery. A 50 mm long 4.5 mm cortical screw was
inserted in lag fashion in a plantaromedial to dorsolateral direction. The implant
is intact. Mild osteophyte formation is evident at the dorsolateral aspect of the
distal intertarsal joint (white arrow). This was a common finding at long term
follow-up. No other complications are identified. In this horse, slight narrowing of
the joint space of the tarsometatarsal joint (white arrowhead) was present
preoperatively and remained unchanged over time.
Figure 29.16 Transverse schematic
illustrating areas of the sustentaculum tali
which communicate with (red) or are out
with (yellow) the tarsal sheath. Source:
Adapted from McIlwraith et al. [6].
dorsoplantar A and lateromedial B radiographic views of tarsal region showing suture screws inserted into the lateral and proximal aspect of the calcaneus to facilitate the repair of the ruptured retinaculum
Dorsoplantar (flexed) oblique view of the hock of a 3-week-oldThoroughbred foal with a malformed hock. Lateral is to the right. There is flatteningof the sustentaculum tali (arrow).
Figure 99-22. (A) Lateromedial radiographic view showing osseous proliferation of the distal aspect of the sustentaculum
tali. (B) Note the substantial new bone formation on the skyline view of the sustentaculum tali. These lesions are associated with chronic irritation and inflammation of the sheath of the deep digital flexor tendon
Figure 99-23. DMPLO (A) and skyline (B) radiographic view illustrates chronic calcification in the deep digital flexor tendon and in its tendon sheath at the medial aspect of the tarsus.
diagnosis
Figure 85-10. Three-week-old Quarter Horse foal with an avulsion of the gastrocnemius muscle.
(A) Weight-bearing results in marked flexion of the tarsus and hyperextension of the stifle. (B) Application of a tube cast over the tarsus allows the foal to bear weight.
What are the types of fracture in distal tibia?
Adults
Lateral and medial malleoli**
**DIRT
Larger incl. more tibia Other articular tibial #
*Foals
- Salter Harris
–>**Types III, IV **Combinations
Figure 99-10. Lateromedial radiograph showing a large fracture fragment including the distal intermediate ridge of the tibia (A). This fracture was fixed with two cortical lag screws across the fracture
plain (B).
what to do?
Figure 35.1 (A) Craniocaudal and (B) lateromedial radiographs
depicting highly comminuted diaphyseal fracture of the tibia in an adult horse. Attempts at repair are futile.
Figure 35.2 (A) Craniocaudal and (B) lateromedial radiographs
depicting simple spiral diaphyseal fracture of the tibia in a foal.
Double plate repair can be successful in most foals.
Figure 35.11 Repair of type II fracture of the proximal tibial physis
shown in Figure 35.3, using two narrow 4.5 mm dynamic compression
plates. Craniocaudal radiographs (A) immediately postoperatively and
(B) four months postoperatively showing healed fracture
Tibial tuberosity fractures how to repair?
Conservative crosstying to prevent recumbency or if displaced (figure) open reduction and internal fixation. Figure 35.14 Large distracted intraarticular tibial crest fracture in a nine‐year‐old Thoroughbred. (A) Preoperative lateromedial radiograph
showing effects of tension from the patellar ligament insertions on the fractured tibial crest. (B, C) Repair of the fracture using three
6.5 mm partially threaded lag screws, and supplemented with two broad 4.5 mm locking compression plates attached with a combination
of cortical screws and locked screws.
Figure 35.12 The 4.5 mm locking compression T‐plate suitable for
repair of proximal tibial physeal fractures in foals.
Figure 35.15 Smaller nonarticular tibial crest fracture in a 13‐year‐old Warmblood repaired using tension band screws and wire.
(A) preoperative lateromedial radiographs showing the tibial crest fracture (arrows). (B, C) Lateromedial and craniocaudal radiographs
seven days after repair using 5.5 and 4.5 mm screws, washers, and tension band wires. Note that the screws have already deformed,
indicating marginal stability. Healing was uneventful.
can repair of diaphyseal tibial fractures be performed?
Not in adults, only in small breeds of horse such as ponies and miniature horses
describe surgery according to Lambert 2018
MIPO or open approach
LR with affected limb down for unila arthod
Needle inserted in the medial aspect of PIT, DIT and TMT confirmed via fluoro
3.2 mm drill bit in fanning tx removed articular cartilage of DIT and TMT and drill holes packed with **synthetic bone putty
MIPO using LCP plate at the level of central tarsal bone make incision 5 cm distal to TMT **and place subcut the plate in distal-to-proximal direction
Screw through stab incisions
**LCPT, a 5-hole, 4.5mm plate was used and once plate positioning confimed via fluoroscopy, plate was contoured using plate benders and with push-pull device the plate was affixed to the MTIII through the second most distal combi-hole in longitudinal axis of the plate
3.2 mm thread hole drilled in the central tarsal bone in the central hole of the transverse axis of the plate
Measurement with depth gauge
Hand tap using 4.5mm tap and insertion of 4.5 mm cortical screw** of appropriate length
Cortical screw in LOAD position in the **third hole from the top
Locking drill guid affixed to the threaded portion of the stacked hole** at the dorsal aspect of transverse segment of the plate
4.3mm drill bit used to drill through central tarsal bone.
The hole was measured using depth gauge and a** 5.0mm LHS inserted**
The remainder of the plate holes were secured with LHS
The distal shaft of the LCP T‐plate
is manufactured in 4‐, 6‐, 8‐, and 10‐hole lengths, providing
different sizes to accommodate varying configurations
of the proximal fracture and increased‐sized
foals
