Chapter 95 - Carpus fractures Flashcards
name the view
Lateromedial
Lateromedial
name the view
Dorsopalmar
Dorsopalmar
name the view
Dorso 45º lateral-palmaromedial
oblique (D45L-PaMO) (
Dorso 45º medial-palmarolateral
oblique (D45M-PaLO) or palmaro 45º
lateral-dorsomedial oblique
(Pa45L-DMO)
name the view
Dorso 45º medial-palmarolateral
oblique (D45M-PaLO)
name the view
palmaro 45º
lateral-dorsomedial oblique
(Pa45L-DMO)
Radiographic anatomy
of the D45M-PaLO projection of the
carpus.
name the view
Flexed lateromedial (flexed LM)
Flexed lateromedial (flexed LM)
name the view
Dorso 85º proximal-dorsodistal oblique
(D85Pr-DDiO) or ‘skyline’ view of the
distal radius
Dorso 55º proximal-dorsodistal
oblique (D55Pr-DDiO) or ‘skyline’ view
of the proximal row of carpal bones
name the view
Dorso 55º proximal-dorsodistal
oblique (D55Pr-DDiO) or ‘skyline’ view
of the proximal row of carpal bones
Dorso 35º proximal-dorsodistal
oblique (D35Pr-DDiO) or ‘skyline’
view of the** distal row of carpal bones**
How many joints does the carpus contain?
Three
antebrachiocarpal joint,
middle carpal joint,
and carpometacarpal joint
Which joints in the carpus always communicate with each other?
Middle carpal and carpometacarpal
What is a critical consideration when performing regional anesthesia in the proximal palmar metacarpal region?
Risk of puncturing the carpometacarpal joint, palmar outpouchings of the carpometacarpal joint extend distad
In which joint are injuries most commonly found in the carpus of horses?
Antebrachiocarpal joint
Name the proximal row of carpal bones
radius; the proximal row of carpal bones (radial carpal, intermediate carpal, and ulnar carpal bones);
Name the distal row of the carpus
distal row of carpal bones (second,
third, and fourth carpal bones);
Name the bones of the metacarpal region
metacarpal (MC) bones II, III, and IV; the accessory carpal bone; and occasionally a first carpal bone (but rarely a fifth).
Name the ligaments of the carpus and tendons related to the carpus
1.** intercarpal ligaments,
2. collateral ligaments,
3. fibrous joint capsule,
4. palmar carpal ligaments.**
TENDONS
1. extensor carpi radialis and 2.** common digital extensor** tendons as well as their sheaths span the carpus dorsally and dorsolaterally, respectively
3.** lateral digital extensor tendon** courses over the lateral side of the carpus, as does the tendon of the 4. ulnaris lateralis
How are the extensor carpi radialis and common digital extensor tendon are maintained against the surface of the carpus?
surface of the carpus by the extensor retinaculum located at the distal radius approximately at the level of the physeal scar.
What is inside the carpal canal?
The carpal canal, a synovial structure containing the superficial and deep digital flexor tendons (SDFT and DDFT), median artery and nerve as well as the accessory ligament of the superficial digital flexor tendon (ALSDFT), is located palmar and medial to the palmar carpal ligaments. Immediately medial to the carpal canal is the tendon and tendon sheath of the flexor carpi radialis, which is an important surgical landmark for** desmotomy of the ALSDFT.**
Which 2 joints can be acessed palmarly for osteochondral fragments removal?
Arthroscopic evaluation of the palmar aspect of the antebrachial
and middle carpal joints can be accomplished
Areas
that can be accessed via palmar approaches to the antebrachial and
middle carpal joints
caudal medial and lateral radius; the palmar aspects of the radial, ulnar, second, third, and fourth carpal bones dorsal aspect of the accessory carpal bone.
which ligaments can be seen through palmar arthroscopic investigation
palmar bundles of the medial palmar intercarpal ligament (MPICL) are easily recognized, but the palmar bundles of the lateral palmar intercarpal ligament (LPICL) cannot be seen by this approach
which structures prevent lesions by dissipating the axial loading during weight bearing?
The
anatomic position of the carpal bones and the resultant transmission
of forces to the intercarpal ligaments protect the weightbearing
surfaces of the carpal bones during exercise to prevent
injury
whena are the carpal bones visible radiographically?
At about 300 days of gestation, all bones of the carpus and tarsus are visible radiographically. The ulnar styloid process, which is the last ossification center to appear, is still not seen at this time.
Namer the grades of ossification for cuboidal carpal bones
The following four grades have been established:
Grade 1: Some cuboidal bones of the carpus and tarsus have no evidence of ossification.
Grade 2: All cuboidal bones (carpus and tarsus) have some evidence of ossification. The proximal physes of the MCIII/MTIII are open.
Grade 3: All cuboidal bones (carpus and tarsus) are ossified, but small and rounded edges are present. Joint spaces are wide and the lateral styloid process and malleoli are distinctly visible. Proximal physes of MCIII/MTIII are closed.
Grade 4: All criteria of grade 3 are met. Cuboidal bones are shaped like corresponding adult bones and joint spaces have the expected width.
when is the closure of the radial physis?
Name some carpal injuries that can occur in all breeds
Trauma from direct blows/kicks
osteochondral fragments
simple or comminuted fractures
subchondral injuries
lacerations
septic conditions
soft tissue (ligaments/tendons)
Bones: 1- Radius, 1a- body (medial aspect), 1b- styloid process; 2- Third metacarpal bone,
2a- body, 2b- proximal tuberosity; 3- Fourth metacarpal bone;
Joints: 4- Medial collateral ligament; 5- Lateral collateral ligament; 6- Third intermetacarpal
syndesmosis;
Muscles and tendons: 7- Extensor carpi radialis tendon; 8- Extensor carpi obliquus muscle,
8a- body, 8b- tendon; 9- Dorsal (common) digital extensor muscle, 9a- body, 9b- tendon; 10- Lateral
digital extensor muscle, 10a- body, 10b- tendon, 10c- accessory ligament; 11- Accessory digital
extensor tendon; 12- Ulnaris lateralis muscle; 13- Extensor retinaculum
Bones: 1- Radius (distal metaphysis); 2- Lateral styloid process (ulna); 3- Accessory carpal bone;
4- Third metacarpal bone, 4a- body, 4b- proximal tuberosity; 5- Fourth metacarpal bone;
Joints: 6- Lateral collateral ligament, 6a- superficial layer, 6b- deep layer; 7- Third intermetacarpal
syndesmosis;
Muscles and tendons: 8- Extensor carpi radialis tendon; 9- Extensor carpi obliquus muscle,
9a- body, 9b- tendon; 10- Dorsal (common) digital extensor muscle, 10a- body, 10b- tendon;
11- Lateral digital extensor muscle, 11a- body, 11b- tendon, 11c- accessory ligament; 12- Accessory
digital extensor tendon; 13- Extensor retinaculum; 14- Ulnaris lateralis muscle, 14a- body,
14b- short tendon, 14c- origin of the long tendon; 15- Deep digital flexor muscle; 16- Flexor retinaculum;
17- Superficial digital flexor tendon.
Antebrachial bones: 1- Radius, 1a- distal metaphysis, 1b- radial styloid process, 1c- sulcus of the
extensor carpi radialis tendon, 1d- sulcus of the dorsal digital extensor tendon, 1e- radial (antebrachial)
condyle, 1f- dorsal locking glenoid surface; 2- Ulna (distal condyle);
Carpal bones: 3- Radial carpal bone; 4- Intermediate carpal bone; 5- Ulnar carpal bone;
6- Second carpal bone; 7- Third carpal bone, 7a- radial fossa, 7b- intermediate fossa; 8- Fourth
carpal bone;
Metacarpal bones: 9- Third metacarpal bone, 9a- body, 9b- proximal tuberosity; 10- Fourth
metacarpal bone;
Joints: 11- Antebrachiocarpal joint; 12- Mediocarpal joint; 13- Carpometacarpal joint; 14- Medial
collateral ligament; 15- Lateral collateral ligament, 15a- superficial layer, 15b- deep layer; 16- Dorsal
radiointermediate ligament; 17- Dorsal intermedioulnar ligament; 18- Dorsal secondotertius ligament;
19- Dorsal tertioquartal ligament;
Other structures: 20- Extensor carpi radialis distal insertion; 21- Lateral digital extensor tendon;
22- Dorsal antebrachial interosseous artery; 23- Dorsal arterial network of the carpus.
1- Radius (distal metaphysis); 2- Lateral styloid process (ulna); 3- Accessory carpal bone; 4- Lateral
collateral ligament, 4a- superficial layer, 4b- deep layer; 5- Extensor carpi radialis tendon; 6- Dorsal
(common) digital extensor tendon; 7- Lateral digital extensor tendon, 7a- accessory ligament (cut);
8- Extensor retinaculum; 9- Ulnaris lateralis muscle, 9a- body, 9b- short tendon, 9c- long tendon;
10- Deep digital flexor muscle; 11- Antebrachial fascia (cut); 12- Accessoriometacarpal ligament;
13- Palmarolateral recess of the mediocarpal joint; 14- Proximolateral recess of the carpal sheath;
15- Dorsal antebrachial interosseous artery; 16- Dorsal arterial network of the carpus; 17- Palmar
arterial network of the carpus.
Bones: 1- Radius, 1a- medial aspect, 1b- styloid process; 2- Accessory carpal bone; 3- Second
metacarpal bone; 4- Third metacarpal bone; 5- Fourth metacarpal bone;
Joint structures: 6- Medial collateral ligament; 7- Lateral collateral ligament (superficial layer);
Muscles and tendons: 8- Extensor carpi obliquus tendon; 9- Dorsal (common) digital extensor
tendon; 10- Lateral digital extensor tendon, 10a- accessory ligament; 11- Ulnaris lateralis muscle;
12- Flexor carpi ulnaris muscle; 13- Antebrachial fascia, 13a- opening for the dorsal ramus of the
ulnar nerve; 14- Flexor retinaculum; 15- Palmar metacarpal fascia; 16- Superficial digital flexor
tendon; 17- Deep digital flexor tendon; 18- Accessory ligament of the deep digital flexor tendon;
19- Third interosseous muscle (suspensory ligament); 20- Distal radial artery; 21- Cephalic
vein (cut).
what do both palmar intercarpal ligaments?
Both PICLs connect the proximal and distal row of carpal
bones, one medially (MPICL) and one laterally
(LPICL)
where does the medial intercarpal bone comes from to?can you evaluate arthroscopically?
MPICL runs from the radial carpal bone
to the second and third carpal bone has since been
recognized as consisting of two branches. The dorsal aspect of the MPICL can be evaluated
arthroscopically, but the majority of the ligament is
inaccessible
where does the lateral intercarpal bone comes from to?can you evaluate arthroscopically?
ulnar and intermediate carpal bones to the palmar aspect
of the third and fourth carpal bones. The dorsal aspect of
the LPICL can be examined arthroscopically.
What is more common? lesions on the medial or lateral palmar intercarpal ligament?
++++ commonly MPICL - most LPICL lesions are avulsion fractures from ulnar carpal bone
What is the surgical access for removal of avulsion fractures of the lateral palmar intercarpal ligament?
Removal of avulsion fractures of the LPICL is done using a dorsomedial arthroscope portal and a dorsolateral instrument portal with the carpus almost maximally flexed
Figure 27.11 Lateral palmar intercarpal ligament avulsion fracture from the ulnar carpal bone. (A) Dorsolateral to palmaromedial oblique,
(B) dorsal 20° lateral‐palmar medial oblique, and (C) dorsopalmar projections show the varying appearances of the fracture (arrows),
depending on projection. Two fragments are visible in (A) and (C). (D) Arthroscopic images show the pair of fragments (1, 2) associated
with avulsion of the lateral palmar intercarpal ligament (LPICL). (E) Dissection of the fragments. (F) Removal of the fragments with
rongeurs. (G) Fracture bed after fragment removal showing residual intercarpal ligament insertion on the palmar medial corner and
palmar midline portion (arrows) of the ulnar carpal bone.
Which joint is most prone to injury from high-energy impacts like falls or kicks?
Antebrachiocarpal joint
What can lead to cartilage injury and fracture in horses?
Osteochondral fragmentation
What is a common finding in horses with carpal injury due to exercise?
Sclerosis in specific bone areas
What anatomical structures are key to the function of the carpus?
The cuboidal bones and hyaline cartilage
What are the structures contained in the carpal canal?
5 structures
SDFT
DDFT
Median artery
and median nerve
ALSDFT
Immediately medial to the carpal canal what is the name of the structure?
Flexor carpi radialis and its tendon sheath
What is the surgical acess of tenoscopic evaluation of the carpal tendon sheath? Landmarks
Lateral digital extensor
Ulnaris lateralis m.
6-8 cm to radial physis
Figure 4-69 Avulsion fragmentation of the lateral palmar intercarpal ligament (LPICL) origin from the ulnar carpal
bone in the right carpus. A, Dorsolateral-palmaromedial oblique (DLPMO) radiograph shows cystic appearance in
ulnar carpal bone with tell-tale osseous fragments (arrows) in cavity. B, Radiographic projection between DLPMO and
dorsoproximal shows the larger fragment (C). Dorsopalmar projection reveals the cystic origin of the fracture (black
arrow), with fragments adjacent to avulsion bed. D, Arthroscopic view using standard dorsolateral portal (between
ECR and CDE tendons) shows two fragments along palmar surface of the ulnar carpal bone (1,2) and a small residual
intact medial portion of the LPICL. E, Dissection of fragment form LPICL using small 1⁄8” AO elevator. F, Fragment
retrieval can be done with small rongeur, ethmoid rongeur, or mosquito hemostats. G, Residual medial and lateral portions
of the LPICL (arrows) after avulsion removal.
Figure 12-31 Composite tenoscopic view of the carpal sheath contents, with the arthroscope inserted proximolaterally.
The deep digital flexor tendon (DDFT) (D) is the only visible tendon on the lateral side of the flexor
tendon bundle. Repositioning the arthroscope more cranially shows the caudal aspect of the radius (R), including
the slight prominence of the closed distal physis, the cranial aspect of the DDFT, and the radial head of the DDF
(RH). C shows an instrument pressing on the intrusion of the distal limits of the accessory ligament of the superficial
digital flexor over the medial wall of the sheath. The DDFT and the caudal aspect of the radius are also visible. The
arthroscope can be positioned caudally to reveal the caudal surfaces of the DDFT and SDFT (S), as well as the caudal
surface of the tendon sheath (TS).
Can you see the landmarks of the latareal palmar intercarpal ligament in the palmar acess of ACB joint?
NO, but medial palmar intercarpal ligament yes
what structures can be accessed via palmar approaches of antebrachial and middle carpal joints nclude…
medial radius
lateral radius
palmar radial
palmar ulnar
palmar second third adn fourth carpal bones
dorsal aspect of acessory carpal bone
Palmar bundles of the medial palmar intercarpal ligamnet
where do osteochondral fragments develop in the carpus?
dorsolateral and dorsomedial aspects of
the antebrachiocarpal joint
Racing horses develop injury to the middle carpal joints where?
Injury of the middle carpal joint in racing breeds (with the exception of external trauma) nearly always involves the
medial aspect of the joint—that is, the radial facet of the third carpal bone, the distal aspect of the radial carpal bone, and the medial aspect of the distal intermediate carpal bone
Osteochondral fragmentation of the distal radial carpal and proximal third carpal bones is associated with
subchondral bone damage caused by repetitive loading
Osteochondral fragmentation of the distal radial carpal and proximal third carpal bones is associated with _________ prognosis after fragment removal and debridement
These locations are prone to reinjury following arthroscopic fragment removal and débridement, leading to a poor prognosis because of subsequent joint deterioration from cartilage debris and subchondral bone failure
60% of the fractures occurred in the antebrachiocarpal joint and 40% in the middle carpal joint
What is the % carpal fractures per joint affected with OCD in THO ?
60% of the fractures occurred in the antebrachiocarpal joint and 40% in the middle carpal joint
Figure 24.3 Diagram illustrating the arthroscopic approach to
remove a fragment from the distal aspect of the radial carpal
bone. The arthroscope is placed through the lateral portal with
the lens angled proximad and instruments are brought through
the medial portal. Source: McIlwraith et al. [24].
Figure 27.12 Radiographs of multiple palmar osteochondral
fragments (arrows), recognized following recovery from
anesthesia for colic surgery.
Figure 27.14 Palmar fractures of the radial and intermediate carpal bones. (A) Dorsopalmar and (B) lateromedial radiographs identify fractures (arrows) in the palmar aspect of the antebrachiocarpal joint. (C) Preoperative computed tomography shows multiple fractures on the palmar aspect of the radial carpal bone (white arrows), a fracture bed on the proximal aspect of the intermediate carpal bone (black
arrows), and the displaced large fragment off the intermediate carpal bone located in the radial fossa. (D) The surgical procedure starts with exploration and debridement of the dorsal compartment of the antebrachiocarpal joint, which is then temporarily closed with towel clamps, and followed by the palmar medial approach with arthroscope and instrument portals adjacent to each other. (E) Arthroscopic
appearance of cartilage erosion on the dorsal distal aspect of the radius. (F) Palmar fragments being elevated for removal from the radial carpal bone, and (G,H) intermediate carpal bone.
Figure 27.6 (A) Flexed lateral to medial radiograph of distal radial carpal bone fragment; (B) arthroscopic view after the fragment has
been elevated before removal, and (C) following completion of debridement
Figure 95-1. T2-weighted transverse magnetic resonance image of a 3-year-old Quarter Horse filly with increased signal (arrows) consistent with LPICL injury between C3 and C4.
Figure 95-2. Dorsolateral to palmaromedial 45-degree oblique projection of a Thoroughbred with an osteochondral fragment of the distal medial aspect of the radial carpal bone.
Figure 95-3. Dorsomedial to palmarolateral oblique radiograph of the carpus of a Thoroughbred with an osteochondral fragment of the distal lateral aspect of the radius. Note the enthesiophyte formation and subchondral lysis consistent with osteoarthritis.
Arthroscopic landmark for antebrachiocarpal (radiocarpal) joint
Carpus flexed 120-130º
Lateral portalbetween the extensor carpi radialis tendon and the common digital extensor tendona
Medial portal 10 mmmedial to the extensor carpi radialis tendon, to avoid its tendonsheath center of a triangle formed by the extensor carpiradialis, the** distal rim of the radius**, and the dorsal rim of the radial carpal bone
Arthroscopic landmark for middle (intercarpal) joint
Carpus flexed 70º
Lateral portal is halfway between the extensorcarpi radialis tendon and the** common digital extensor tendon**and midway between the two rows of carpal bones
Medial portal 10 mm medial to the extensor carpi radialis tendon, to avoid its tendon sheath,
What is the surgical acess of palmarmedial arthroscopic antebrachiocarpal joint? Landmarks
Flexion of 20-30º
Palmaromedial pouch is more voluminous approached palmar to the medial collateral ligament at the level of **distal radius and dorsal to the tendon insertion** of** flexor carpi radialis** and medial palmar vein
Palmarolateral approach to the antebrachiocarpal joint ismade more complex. How many approachs are? why?
Palmarolateral approach to the antebrachiocarpal joint ismade more complex. How many approachs are? why?
What is the palmarolateral pouch that usually is bigger and accessed easier?
The proximal outpouching between the caudalradius and proximal margin of the accessory carpal bone is largerand provides clinically useful access to the accessoriocarpal radialarticulation. Arthro in proximal portal and distal instrument portals adjacent to articular surfaces
Which area is prone to reinjury following arthroscopic fragment removal and débridement?
Distal row of carpal bones
What is usually associated with avulsion fractures of the vestigial metacarpal bones or distal radius?
Injury to the extensor tendons
What can be challenging to differentiate from lameness originating from other structures of the carpal region?
Lameness caused by structures within the carpal canal
What is the most likely cause of lameness in horses related to carpal chips?
Trauma
Which breeds are particularly prone to carpal chip fractures?
Racing breeds
What can lead to ischemic necrosis of the subchondral bone in the third carpal bone?
Reduction in vascular channels
What clinical signs are used for diagnosing carpal chip-related lameness?
Lameness, painful response to carpal flexion, and joint effusion
What diagnostic tool is recommended when a carpal chip is detected radiographically?
Contralateral radiographs
What is associated with reduced postoperative racing prognosis in horses with carpal chip
Long-standing carpal chips
How are small 2.7-mm cortex screws used in the repair of larger osteochondral fractures of the carpus under arthroscopic guidance?
They are used for joint compression during arthroscopy.
What the most affected place in carpus with osteochondral fragments?
distal aspect of radial carpal bone
At what degree is the carpal flexion typically set for arthroscopy of the dorsal compartment of the middle carpal joint?
70 degrees
arthroscopy of the dorsal compartment of the antebrachiocarpal joint, carpal flexion is
120 to 130 degrees
Factors associated with reduced postoperative racing prognosis
long standing carpal chips, repeated joint injection,reduced response to joint injection, injury early in training, poor preoperative racing record, or previous carpal surgery.
Where are the standard arthroscopy portals for the antebrachiocarpal and middle carpal joints located?
Between the common digital and extensor carpi radialis tendons (lateral portal)
What size should the arthroscopy portals be made to allow egress of fluid without its accumulation in the subcutaneous space?
6-8 mm
What is the recommended postoperative treatment for routine osteochondral carpal arthroscopy?
2 weeks of stall rest, 2 weeks of stall rest with hand walking, and 2 weeks of pasture exercise
What is the angle of projection for the** distal radius?**
What is the projection for the proximal row of the radius?
What is the projection for the distal row of the carpus?
How do you diagnose the stress remodeling and subchondral lucency?
Figure 95-5. Tangential (skyline) projection of the left carpus of a 4-year-old Standardbred demonstrating sclerosis (white arrows) and lucency (black arrows) of the radial facet of the third carpal bone consistent with third carpal bone degeneration. Medial is to the right of the image.
Grade 1 lesion displaying fibrillation at the edge of the defect and full-thickness articular cartilage damage extending less than 5 mm from the fracture line where fragmentation was removed Gaham 2020
Grade 2 lesion demonstrating articular loss extending more than 5 mm from the defect and involvement of up to 30% of thearticular surface
Grade 3 lesion showing loss of 50% or more of the articular cartilage
Grade 4 lesion with significant loss of SCB
diagnosis
Figure 95-9. Lateral radiographic view of the carpus of a Thoroughbred with a minimally displaced, complete frontal plane slab fracture of the third carpal bone (arrow). Notice the osteochondral fragment (trough lesion) at the proximal articular surface.
Figure 95-10. Dorsopalmar (A) and skyline (B) view of a schematic drawing of arthroscope and needle placement for the surgical repair for a third carpal bone slab fracture under arthroscopic guidance. One needle is placed on each end of the fracture, one in the carpometacarpal joint, and one centered over the middle of the slab fracture in the middle carpal joint to serve as guides for the location and direction of screw placement.
Figure 95-12. Lateral radiographic view after repair of a third carpal bone frontal plane slab fracture with a single 3.5-mm cortex screw placed in lag fashion.
extra radiographs needed?
Figure 24.12 Radiographs of a displaced frontal plane slab fracture of the radial facet of the third carpal bone: (a) lateromedial, (b)
dorsolateral–palmaromedial oblique, (c) flexed lateromedial and (d) flexed dorsoproximal–dorsodistal oblique (skyline) projections.
Note the fracture reduction produced by carpal flexion. The dorsopalmar depth of the fracture and bone thickness have been determined (c) in preparation for surgery. S
Ideal radiographs for slab fractures depending on the site
arthroscope position and placement of needles for fixation of a
frontal plane slab fracture of the third carpal bone.
dx and projections
Figure 24.15 Repair of a displaced slab fracture of the radial facet of the third carpal bone using a 4.5 mm cortex screw. (a)
Dorsolateral–palmarolateral oblique. (b) Flexed dorsoproximal–dorsodistal oblique radiographs at presentation. (c) Flexed
lateromedial projection at completion of surgery.
dx and projections
Figure 24.16 Repair of a displaced frontal plane slab fracture of the intermediate facet of the third carpal bone. Fracture identified
on dorsomedial–palmaromedial oblique (a) and flexed dorsoproximal–dorsodistal oblique (b) radiographs. (c) Post-operative
dorsomedial–palmarolateral oblique projection following repair with a single 3.5 mm cortex screw.
Ramzan et al 2019 EVE mentions a new approach for radiograph of sagital fracture of the third carpal bone what is it?
on a dorsoproximal lateral-palmarodistal medial oblique
Figure 95-11. Intraoperative radiographic view of the carpus of a Thoroughbred during surgery for repair of a third carpal bone slab fracture. Notice the placement of the needles to identify the borders of the fracture and the marker drill bits to confirm proper placement and orientation of the implants.
Figure 95-13. Tangential radiographic view of a third carpal bone of a Thoroughbred after repair of a frontal plane fracture (arrows) with two 3.5-mm cortex screws placed in lag fashion.
Figure 95-14. (A) Dorsolateral to palmaromedial oblique radiographic views of a frontal and sagittal plane slab fracture of the third carpal bone of a Thoroughbred. (B) Skyline projection of the same horse. (C) Dorsopalmar projection of the same horse after placement of two 3.5-mm cortex screws in lag fashion to stabilize the multiple plane fracture.
projection and dx
Figure 95-15. (A) Dorsolateral to palmaromedial oblique radiographic view of a frontal plane slab fracture of the radial carpal bone of a Thoroughbred. (B) Flexed lateral radiograph after repair of the radial carpal slab fracture using two 4.5-mm cortex screws placed in lag fashion.
Figure 95-16. (A) Dorsopalmar projection of a 3-year-old racing Thoroughbred with a sagittal plane slab fracture of the medial aspect of the third carpal bone (arrow). (B) Skyline projection of the third carpal bone after repair with a 3.5-mm cortex screw placed in lag fashion to compress the fracture.
Describe how you would place the screws during arthroscopy of third carpal slab fracture
One needle is placed on each end of the fracture, one in the carpometacarpal joint, and one centered over the middle of the slab fracture in the middle carpal joint to serve as guides for the location and direction of screw placement.
Position of the horse for arhtroscopy of the antebrachial joint
Extended joint
Position of the horse for arthroscopy of the middle carpal joint
Flexed 70º
Portal for arthroscopy of the middle carpal joint
projection + diagnosis
Fig 2: a–c) Dorsolateral-palmaromedial oblique view (a),dorsopalmar view (b), and tightly collimated dorsopalmar viewhighlighting the medial aspect of the antebrachiocarpal joint (c)of the left carpus. A well-defined oval osseous cyst-like lesion ispresent within the radial carpal bone (black arrows andarrowheads). A sclerotic rim surrounds the lesion. Note thepresence of small periarticular osteophytes at the medial marginsof the antebrachiocarpal joint consistent with mild degenerativejoint disease (white arrowhead) Hargreaves et al 2019 EVE
treatment
A 1 cm incision was
made over the medial aspect of the radial carpal bone at a
level identified by CT. A 2 mm drill hole was then made to enter
the lesion. A 1.5 mm diameter arthroscopic curette with a
previously conditioned curve placed in the shaft was
introduced and the cystic cavity curetted. An 18 g stainless
steel, 10 cm spinal needle was used to inject 10 mg of
triamcimalone acetonide (1 mL) into multiple sites of the lesions
fibrous lining. Repeat CT was performed to ensure that there
was no collapse of the radial carpal bone. Hargreaves et al 2019 EVE
describe
Fig 1: Bone phase scintigraphic images of the distal limbs, both lateral and dorsal images. Black arrows indicate increased
radiopharmaceutical uptake (IRU) within the left radial carpal bone on both a lateral and dorsal image. Hargreaves 2019 EVE
name the instrument
FIGURE 5 Image of a 1.2-mm-diameter, 65-mm-long needle
arthroscope inserted through its corresponding cannula. Note that the needle arthroscope slightly protrudes out of the cannula (circle) and has a sharp edge. This feature was associated with the presence of mild iatrogenic cartilage damage during phase 2 Kadic et al 2020
projection + dx
F I G U R E 1 Dorsoproximal-dorsodistal oblique (DPr-DDiO) radiograph of the carpus illustrating a complete sagittal fracture of the radial facet of the third carpal bone. The fracture plane curves medially to exit at the articulation between the second and third
carpal bones Tallon et al 2020
Projection and tx
F I G U R E 5 Dorsoproximal-dorsodistal oblique (DPr-DDiO)radiograph of the carpus illustrating placement of a 3.5-mm corticalscrew across the fracture planeR Tallon et al 2020
projection +vdx
F I G U R E 2 Dorsoproximal-dorsodistal oblique (DPr-DDiO)
radiograph of the carpus illustrating an incomplete sagittal fracture of the radial facet of the third carpal bone Tallon et al 2020
F I G U R E 3 Two 20 ga needles positioned percutaneously to
delineate the articulation of the third and second carpal bones
(red), the lateral margin of the fracture (green) and a third needle
positioned along the proposed screw track (blue)
Describe how the screw was placed (Tallon et al 2020)
horse positioned in dorsal recumbency. The
middle carpal joint was examined arthroscopically using standard portal placement. The margins of the fracture and the articulation between C2 and C3 were marked with 20G needles, with a third needle used to mark the proposed plane of a screw. Unlike frontal plane slab fracture repair, the needle was not positioned by externally bisecting the two previous marker needles but was placed so that the plane crossed the third carpal bone by the dorsal medial margin, and crossed a portion of the fracture fragment, as judged by arthroscopic visualisation. It was not possible to position the needle orthogonal to the fracture plane, and thus the screws were positioned obliquely. A fourth needle was placed marking the carpometacarpal joint. An incision was made distal to the needle marking the proposed plane of the screw, and a 3.5-mm hole was then prepared to a depth of 10 mm or more if indicated. The depth was judged from preoperative radiographs. A loss of pressure suggesting the fracture line had been drilled was not appreciated in any case. 3.5 mm drill guide and 3.5 glide hole in the cis cortex followed by 2.5 mm drill guide and 2.5 mm drill bit through for trans cortex. Countersink. Measure in this case was preop. TAp and insertthe 3.5 mm screw. Arthroscopic visualisation would in many cases confirm accurate location of the screw in the dorsal face of the third carpal bone, distal to the articular surfac. However, in some cases, the screw was positioned too distally to be visualised. Intraoperative radiography was used inconsistently; dorsoproximal dorsodistal oblique views were not obtained in earlier cases due to equipment constraints. Any associated fibrillated articular cartilage was debrided, and degenerate osteochondral material was removed by curettage. The joint was lavaged and the incisions
closed with simple interrupted sutures of monofilament nylon
What type of deformity is typically associated with multifragment fractures?
Carpal varus deformity
what is important for the vet to know before sending the horse with possible comminuted carpal fx??
Fiberglass sleeve cast (ideal to support mediolateral instability
Sleeve casts extend from the proximal antebrachium to distal metacarpus, terminating at the level of the metaphysis of the third metacarpal bone.
OR Fabrice advices Robert Jones with palmar and lateral splints
This horse is submitted to pancarpal arthrodesis you can use 3 short 3 compression plate with T plate as wellThis horse is submitted to pancarpal arthrodesis you can use 3 short 3 compression plate with T plate as well
Pancarpal requires all joints fused and longer plates
with sometimes triple
AVOID implant placement in the diaphysis and MC3 because of risk of fracture
what procedure was performed?
Partial arthrodesis because pancarpal does not allow flexion
What is the indication of stabilization before transport in case of suspected comminuted fracture of carpus?
Lateral and plantar splint
Flexion DR the horse is being submitted to aggressive curetage to do a pancarpal or partial carpal arthrodesis
Full flexion DR the horse is being submitted to aggressive curetage to do a pancarpal or partial carpal arthrodesis - IMPORTANT part
Reduction by traction using winch and place 7-8 hole broad LCP. Make sure you are slightly dorso-lat (ICB)
Reduction by traction using winch and place 7-8 hole broad 4.5 LCP. Make sure you are slightly dorso-lat (ICB) - placed between the extensor carpi radialis (ECR) and the common digital extensor (CDE)
Place the drilling guides for the locking head screws with small incision
Step?
Tunneling to be in contact with bone under the tendons and cartilage
Place the lateral plate really lateral
What is very important for the recovery of the horse?
full limb cast is applied and the horses are recovered with head and tail support.
When can you use a T-plate?
T-plate used in the proximal row to do arthrodesis of the
describe the partial arthrodesis according to Curtis et al 2018
LR, flexion and open debridemetn with 4.0-mm drill bit in multiple directions (not possible arthroscopy due to severe OA)
2 cm skin incision over proximal dorsolateral aspect of the third metacarpal bone
Plate passer to create subcut tunnel over dorsolateral aspect of the third metacarpal bone and dorsoat carpus
Plate was countoured by fluoro guidance
6-hole broad LCP procimal round (stacked) hole was centered over intermediate carpal bone
Stab incisions made #10 blade
4.5-mm cortex screw was placed in the second hole of the plate to compress plate to the bone
Tension device applied in the sixth hole of the plate in the midmetacarpus
4.5-mm cortex screw placed in load in the fifth hole of the plate
Removal of tension device and remaining holes were filled with 5.0-mm LHS
15 cm incision over dorsal ascpet through ECR tendon from proximal row of carpal bones until the prox aspect of MCIII
Removal of callus bone and 5-hole narrow LCP was directly contoured to the dorsal aspect and 4.5-mm cortex screws were placed in the second and fourth holes of the palte into the intermediate carpal bone + MCIII to compress the plate to the bones
remaining holes filled with 5.0-mm LHS
6-hole narrow LCP was contoured to the dorsomedial aspect of the limb and 4.5-mm cortex screw placed in the 5th hole to compress palte against the bone
5 remaining holes filled with 5.0-mm LHS
Autologous cancellous bone graft harvested from the left TC was loosely packed into the middle carpal joint
Antibiotic impregnated polymethylmethacrylate placed over exposed plates prior to closure
describe a pancarpal arthrodesis according to Curtiss et al 2018
LR with affected limb uppermost
Radiocarpal and middle carpal exmained with arthro routine fashion and removal of cartilage with manual and motorized instruments
A full-thickness** 20-cm incision was
made on the dorsal aspect of the limb through the extensor carpi radialis extending from the distal radius** to the proximal metacarpus to the dorsal surface of the intermediate and third carpal bones.
Using fluoro and direc observation 3.5-mm cortex screw was placed in lag fashion to reduce and stabilize the fracture of the fourth carpal bone.
7-hole narrow LCP was contoured to the dorsal aspect of he limb and secured to the radius and metacarpus by using a push-pull reduction device .** Two 4.5-mm cortex screws** were placed in the second and sixth holes of the plate in load. The push-pull reduction device was removed, and the remaining 5 holes were filled with 5.0-mm LHS.
A 6-hole narrow LCP was placed on the dorsolateral aspect of the carpus by using the previously described minimally invasive technique and was secured to the limb by using a push-pull reduction device placed through a stab incision.** All 6 holes of the plate were
filled with 5.0-mm LHS** through stab incisions
7-hole narrow LCP was similarly placed dorsomedially after it was contoured to the limb, and** 5.0-mm LHS** were placed in 6 holes of the plate. The** third hole in this plate was left empty because of concern that screw placement in this location would interfere with previously placed screws. Fluoroscopy was used to guide implant placement** and to aid in contour of the plates placed minimally invasively. Prior to closure,** AIPMMA **was applied around all plat
Projection and dx
FIGURE 3 A, Preoperative DP and DMPLO radiographs of case 3. fracture of the second carpal bone (Figure 3A), which was further assessed with a 0.27T standing magnetic resonance system. Marked comminution of the second carpal bone with biarticular involvement was identified, at which time surgical arthrodesis was elected.
surgical tx and projections
Fig 2: Case 1: Partial arthrodesis of the middle carpal and
carpometacarpal joints with 2 plates (one 7-hole broad locking
compression plate dorsomedially and one 7-hole narrow locking
compression plate dorsolaterally) 24 h post-operative radiographs.
(a) Lateromedial projection, (b) DP projection. carpometacarpal
[CMC], middle carpal [MC] joint or antebrachial carpal.
surgical tx and projections
Fig 4: Case 2: pancarpal arthrodesis with 2 plates (one 12-hole, 5.5 mm broad locking compression plate and one 13-hole, 4.5 mm
broad locking compression plate) 36 h post-operative radiographs. (a) Lateromedial projection, (b) dorsopalmar projection, (c)
dorsomedial–palmarolateral oblique projection.
horses with partial carpal arhtrodesis have how much remaining angles? image is the range motion without sx
42-44º in the article of Brandenberg et al 2018 for CMC and MC joints partial arthrodesis. Image from Lischer
