Hygroma
of Knee:
It is the synovial swelling over the
dorsal surface of the carpus.
Mostly acquired bursitis from trauma.
The tendon of the sheath of extensor
carpi radialis or common digital extensors may be involved.
A synovial hernia of the antebrachiocarpal
or mid carpal joint capsule can occur.
Acquired bursitis shows an evenly
distributed swelling over the surface of carpus.
Etiology:
Trauma, exercise on hard ground, hitting
carpus on the wall.
Signs:
Swelling on the dorsal surface of the carpus.
Diagnosis:
Explore by needle to drain the fuild for
cytological exam.
In Acute Hygroma – serous type of fluid,
and in chronic case synovial type of fluid.
Treatment:
Injection of corticosteroids followed by
elastic bandage counter pressure 3-5 times at weekly intervals.
In acute cases ,drainage by 4 cm
vertical incision , fibrin removed from inner surface with 3 % iodine with
penrose drainage.
Open-Knee:
Irregular profile of the carpal joints
when viewed from the side.This shows as if carpal joints are not fully closed.
This is in young horses (1-3yrs of age ), accompanied by epiphysitis.This is
weak confirmation leading to carpal injury.
Bleemish
Knee:
1.Backward
(palmar) deviation of carpal joints ( CalfKnee or Sheep Knee)
Weak confirmation, seldom sound under
heavy work.
Strain on carpal and radial check
ligaments, and proximal,middle and distal accessory carpal and palmar carpal
ligaments.
Palmar reflection of the
antebrachiocarpal joint capsule.
Increased compression on the dorsal
aspect of the carpal bones.
Chip # of 3rd ,radial and
intermediate carpal bones common and small chip # of radius.
2.Forward (Dorsal) deviation of the
carpal joints(Bucked knees or knee sprung) also goat knee or over in the knees.
By contraction of the carpal flexors,
i.e., ulnaris lateralis, flexor carpi ulnaris, and flexor carpi radialis.
Extra strain on sesamoid bone, the
superficial flexor tendon, extensor carpi radialis and suspensory ligament.
Forward deviation of carpal joints may
be accompanied by enlarged epiphysis or distal metaphysis of the radius.
3.Medial deviation of the carpal
joints(Knock knees)
4.Lateral deviation of the carpal
joints(Bow legs)
5.Tied in knees:
When viewed from the side, the flexor
tendons appear to be too close to the cannon bone just below carpus and ventral
aspect looks as if notched.
6.Cut out under knees:
Cut out appearance just below the carpus
on the dorsal surface of the cannon bone. It is fundamentally weak
conformation.
Fracture
of carpal bone:
Common in race horses, young thorough
breds of 2-4 years of age.
Factors disposing for fracture are
speed, immaturity, longer limb length, position of jockey, distances run which
generate tremendous concussive forces on dorsal surface of carpal bones.
Fractures can be simple chip fractures,
slab fracture or comminuted fracture.
Most common sites of fracture are
radial, 3rd, intermediate carpal bones and distal end of radius.
Collateral fracture by weigth on one
side because of the # in another side.
Counter clock wise direction of racing
by position of rider leads to chip # of right forelimb, and by clock wise
direction racing left forelimb chip #.
Slab # extends through full thickness of
the bone from proximal to distal, commonly 3rd, intermediate and
radial carpal bones.
Communited # commonly radial,
intermediate and 4th carpal bones.
Etiology
of the # of carpus:
1.Trauma from repeated concussion and
external blows.
2.Fatique creates abnormal compression
on the dorsal surface of the carpal bones.
3.Faulty conformation leads to calf
kneed predisposed to carpal #.
4.Improper trimming and shoeing result
in imbalanced foot and unequal distribution of weight will affect carpus.
Signs:
Intra-articular chip # within carpus
result in varying degrees of heat, pain, joint distension and lameness.
By physical exam, synovial distension of
the antebracheal(radiocarpal) joint or mid carpal joint.
In acute chip fracture, synovitis is
diffuse at first, eventuallybecome more localized in soft tissues over chip
fracture, over dorsomedial surface of the carpal joints.
By 3rd carpal bone fracture,
swelling is seen on mid carpal joint.
Degree of lameness depends on extent,
location, duration of the fracture and the amount of degenerative joint
disease.
The assessment of the degree of carpal
flexion and the carpal flexion test can be valuable tools in the diagnosis of
carpal lameness.
Palpation of the dorsal border of each
carpal bone in both joints is important diagnostic tool.
Diagnosis:
Carpal lameness confirmed by
intra-synovial anaesthesia, by injecting 5-10ml of local anaesthetic into
antebrachiocarpal or midcarpal joints after equal amount of synovial fluid
removed.
If the fluid withdrawn is homogenous
dark red fluid, no local anesthetic to be given, as it could be a #.
After 20-30min of injection, lameness is
reevaluated.
Treatment:
Chip Fracture: Decide for conservative
management or surgical removal.
Selection of treatment depends on
physical findings, the size and shape of the chip and its location.
Small Chip # are firmly attached to
parent bone are handled conservatively with a period of rest.
On physical exam they will show mild
pain and lameness.
For large acute chip # with displacement
and free floating that affects weight bearing, treat only by surgery.
Joint more painful on flexion/palpation.
Arthroscopy allows to remove chips
without arthrotomy.
NSAIDS to reduce acute inflammatory
process.
Intrasynovial sodium hyaluronate reduces
synovitis, progressive cartilage destruction and formation of osteophytes.
After chip # is removed, pressure
bandage for 3-4 days, Antibiotics and phenyl butazone for 7 days.
Accessory
carpal bone fracture:
Most common in thorough breds, show
jumpers.
Most common fracture in vertical plane
through lateral groove formed by long tendon of ulnaris lateralis muscle.
The pull of the flexor muscles results
in a constant distraction and the instability with movement results in a fibro cartilagenous
nonunion.
Etiology:
1.Direct external trauma from a kick.
2.Asynchronus contraction of flexor
carpi ulnaris and ulnaris lateralis muscles.
3.Bow string effect of flexor carpi
ulnaris & ulnaris lateralis muscles and flexortendon created when horse
lands on a partially flexed forelimb.
4.Bone caught between 3rd
metacarpal and radius in a nut cracker fashion.
Signs:
Signs of lameness not acute.
Most prominent sign of lameness is
distension of carpal sheath, marked pain with rapid flexon of the carpus.
Abnormal lateral and medial movement of the accessory carpal bone.
Diagnosis:
When carpal sheath is distended, pain on
flexion, lateral radiograph will show up fracture.
Treatment:
Three types of treatment.
1.Conservative treatment—Rest in box
stall for 3-6 months.
2.Internal fixation by lag screw principal.
Two 4.5 mm ASIF screws for interfragmentary compression of the fracture.
3.Removal of the fracture of accessory carpal
bone for vertical fracture and ulnar
neurectomy.
Carpal hyperextension and carpal
arthrosis observed.
Prognosis:
Guarded dependent on fracture, duration
and method of repair and intended use of horse.
Good result by internal fixation for
interfragmentary compression.
Contracted
flexor tendons (knuckling at the fetlock)
Three degrees of the condition.
1.The phalanges are almost vertical.
2.Perpendicular let fall from the front
of the fetlock, strikes the front of hoof.
3.Striking in front of hoof.
In
young animals—
Cause:
Insufficient nutrition to dam.
Muscular debility by confinement to
stable.
Insufficient food.
Digestive troubles.
Muscular rheumatism
Rickets.
The condition more in front legs.
In muscular weakness, patient stands
over knees.
Symptoms:
Complete flexion of affected joints or
some degree of flexion.
Horse stumbles when trotted, leading to
open wound and septic arthritis.
Prognosis:
Congenital – recovers easily.
Acquired – due to some systemic defect,
prognosis guarded.
Treatment:
Aim of treatment is to make toe of the
foot to bear weight.
Splints/POP bandage to maintain foot in
position.
Friebels apparatus to keep fetlock in
position and application of sling for easy recovery.
In
Adults—
Cause:
1. Excess flexion by tendon contraction
folloeing chronic tendinitis.
2.Shortening of structures by ring bone, osteoperiostitis of pastern, chronic
synovitis, contracted foot and corn.
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