◊ 3-Hind Limbs ◊

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II-LAMENESS IN THE HIND LIMB

AFFECTIONS OF THE HIP AND THIGH

1-Azoturia or Monday morning disease

Definition: -

Severe muscular destruction of horses kept on full feed (mainly grains) when they are not worked, and the affected muscles are usually iliopsoas, quadriceps, triceps, gluteal, and biceps femoris.

Etiology: -

Release of high amount of lactic acid from the accumulated muscular glycogen that destroys muscles with release of myoglobin, and the later alters renal function.

Signs: -

Few minutes after starting the work (15 minutes)

1-Pain, stiffness, incoordination, muscular tremor, sweating, and inability to stand.

2-Affected muscles become firm and painful in palpation.                               

3-Dark coffee urine.

Diagnosis: -

1-History and signs

2-Differential diagnosis from thromboembolism (no coffee urine, relieve by rest, and poor circulation by palpation of femoral pulsation or by rectal palpation of iliac arteries).

Treatment: -

1-Immediate rest and tranquilization                   

2-Reduction of acidity and flushing of the kidney

3-Anti-inflammatory

2-Tying-up syndrome or Cording up

Definition: -

It is muscular myopathy that occurs few minutes after the end of severe muscular exertion like racing. Affected muscles are iliopsoas, quadriceps, and gluteal. It is recurrent, associated with muscular cramp, caused by accumulation of lactic acid, and causes no muscular necrosis.

Etiology: -

1-Deficiency of vitamin E and selenium 

2-Reduction of blood supply to muscles with accumulation f lactic acid

Signs: -

Few minutes after the end of severe muscular exertion

1-Stiffness with abnormal flexion of the hind limb

2-Rigid back with motion like back pain                

3-Pain on pressing iliopsoas rectally

4-Pain on pressing loin region, longissimus dorsi in lumbosacral junction, iliopsoas muscle, and in severe cases quadriceps and gluteal muscles

5-Mild myoglobinuria                                            

6-Relieve on motion for few minutes

Diagnosis: -

1-History               

2-Clinical signs              

3-Examination

Treatment: -

1-Reduction of 50% of grains 24 hours before racing               

2-Same line of treatment as azoturia

3-Walk for 30 minutes                                                                

4-Muscle relaxants

Prognosis: -

*Good

3-Myositis of psoas and longissimus dorsi muscles

Definition: -

Sequelae of azoturia or tying-up, characterized by pain in the loin region after severe muscular exertion similar to kidney trouble

Etiology: -

Trauma from muscular strain

Signs: -

1-Stiff attitude of the back and both hind limbs                    

2-Pain on pressing loin                

3-Pain on pressing psoas muscle rectally

4-Rigid abdomen

Diagnosis: -

1-History

2-Signs               

3-Examination 

4-Diferential diagnosis from

a-Injury to sacroiliac or lumbosacral junction, or overlapping of dorsal spinous processes (seldom response permanently to treatment)

b-Tying-up (doesn’t last several days)

Treatment: -

1-Rest up to 3 weeks post disappearance of signs         

2-Vitamin E and selenium         

3-Corticoid

4-Overlapping of thoracic and/or lumbar dorsal spinous processes

Lameness is due to pain caused by pressure on vertical spines by enlarged proximal ends of spinous processes, and signs appear 2-3 years post injury

Etiology: -

Trauma

Signs: -

1-The animal resents saddling and grooming                    

2-Bucking and lying down after saddling

3-Discomfort after tightening cinch                                    

4-Pain on manual pressure over the back

5-Palpation of the summits of spinous processes reveals irregularity

Diagnosis: -

1-History

2-Signs              

3-Examination 

4-Radiographs (diminished space) 

5-Differential diagnosis from tying up syndrome and arthritis of spine

Treatment: -

1-Surgical removal of spine                   

2-Rest for 2 months                    

3-Hand walk for month

Prognosis: -

*Guarded

5-Subluxation of the sacroiliac joint

During Subluxation, pain develops as a result of spasm of muscles and on healing; scar tissue replaces the healthy one and predisposes to re-injury.

Etiology: -

Twisting or high stress over the joint as a result of trauma

Signs: -

Highly variable

1-Variable degree of stiffness and pain in the hind limbs

2-Short anterior stride

3-Pain on pressing tuber coxae for rotation of the pelvis or movement of the joint

4-Pain on pressing the joint or the surrounding tissue with fingers as a result of spasm of muscles for re-establishing joint rigidity

5-Prominence of tuber sacrale over the rump in old cases (hunter’s bumps), or movement of the tuber sacrale in recent cases

6-Crepitation on pressing the joint, or on rectal palpation during motion

Diagnosis: -

1-History

2-Signs              

3-Examination 

4-Injection of the joint with local analgesic

5-Differential diagnosis from pelvic fracture

Treatment: -

1-Rest for a month

2-Injection of the joint and the ventral sacroiliac ligament with irritant to stimulate scar formation

Prognosis: -

*Guarded

*Favorable if the joint is solid and the injury is old with no lameness

6-Fracture of the pelvis

Most commonly affecting shaft of the ilium, tuber coxae, symphisis pubis, or obturator foramen  

Etiology: -

Trauma

Signs: -

Vary according to site of fracture and death may occur if iliac artery is severed

► A-Tuber coxae

1-Very little lameness            

2-Knocked down hip          

3-Protrusion of bone through skin wound

► B-Shaft of the ilium

1-Severe lameness                                                                                       

2-Lifting foot off ground

3-Overriding of fragments causes shortening of the limb                           

4-Short anterior stride

5-Similar signs of hip lameness during motion especially if acetabulum is involved

► C-Symphisis pubis

1-Short anterior phase of stride                                                 

2-Lameness in both hind limbs

Diagnosis: -

1-History

2-Signs              

3-Examination 

4-Differential diagnosis form Subluxation of sacroiliac joint

5-Rectal examination during motion or rotation of pelvis may reveal crepitation or hematoma

Treatment: -

No treatment

1-Rest and slinging 6-8 weeks             

2-Surgical removal of bone sequestrum of tuber coxae

3-Euthansia after one year if the animal is valuable and shows no healing

Prognosis: -

*Guarded

7-Thrombosis of posterior aorta, iliac arteries, or femoral artery

Etiology: -

Strongylus vulgaris

Signs: -

Vary according to size of thrombus

1-Intermittent lameness increases with exercise and decreases with rest

2-Onset of lameness depends upon size of thrombus. Large one causes early lameness after exercise (similar to azoturia), while small one needs excessive exercise to be evident

3-Sweating, pain, and anxiety during lameness                                 

4-No sweating of affected limb

5-Collapsed veins of the affected side

6-Affected limb is cooler with weaker pulsation of femoral artery

7-Supporting leg lameness if the thrombus is bilateral in aorta

Diagnosis: -

1-History

2-Signs              

3-Examination 

4-Rectal examination for strength of pulsation and presence of thrombus

5-Differential diagnosis form azoturia (stiff hard quadriceps muscle and coffee color urine)

Treatment: -

1-Prophylactic anti parasitic             

2-Contracton of thrombus with time                   

3-Euthansia

Prognosis: -

*Guarded

*Unfavorable in case of bilateral involvement or if the condition worsens

8-Dislocation of the hip joint

Equines, opposite to cattle, have high incidence of fracture of the ilium than dislocation of the hip joint. The horse has both accessory and round ligaments of the hip joint, and dislocation ensues as a result of tearing of the later

Etiology: -

Severe trauma as the head of the femur is large and the acetabulum is deep

Signs: -  

1-The femur luxates upward and forward

2-Out ward turning of toe and stifle, and inward turning of the hock

3-Short anterior phase of stride                                               

4-Shortening and dangling of the limb

5-Prominence of greater trochanter                                         

6-Crepitation

7-Luxation of the head of the femur can be detected by rectal examination

Diagnosis: -

1-History

2-Signs              

3-Examination 

Treatment: -

1-Recent cases can be treated by surgical reduction of the head of the femur into acetabulum, and if it remains in place for 3 months, the muscle will keep it in place

2-Euthansia in chronic cases or invaluable animals

Prognosis: -

*Guarded to unfavorable

9-Rupture of round ligament of hip joint

Definition: -

Tearing of the round ligament leading to greater motion of the head of the femur and osteoarthritis without Luxation

Etiology: -

Trauma 

Signs: -

Very similar to Luxation but the limb is of the same length

1-Toe-out, stifle-out, and hock-in

2-Crepitation as a result of increased movement of the femur head or osteoarthritis

Diagnosis: -

1-History

2-Signs              

3-Examination 

4-Differential diagnosis from luxation              5-Rdaiographs

Treatment: -

Stabilization of the joint with toggle pin apparatus for horses not used for running, or for cattle

Prognosis: -

*Unfavorable

10-Trochanteric bursitis or Whorlbone lameness

Definition: -

It is a true bursistis due to inflammation of the cartilage of the great trochanter, the bursa over the cartilage of the great trochanter, and the strong flat tendon of the middle gluteus muscle as it passes over the convexity of the trochanter major to inserts into the crest of the femur

Etiology: -

1-Trauma and bruising of the bursa              

2-Straining of the tendon

Signs: -

1-The limb is flexed at rest                         

2-Atrophy of the gluteal muscle in old cases

3-The horse carries the leg inward and sets it down in a line between forelimbs

4-Wearing of the inside of the toe

5-Short stride of the affected limb forces the hind quarters to move toward sound side, so the horse travels in dog fashion

6-If the lesion is traumatic, with fracture of he bone or the cartilage of trochanter major, persistent lameness is present

7-Pain ensues on pressing the great trochanter

Diagnosis: -

1-History

2-Signs              

3-Examination 

4-Infiltration analgesia over trochanter major

5-Differential diagnosis from inflammation of the hip joint, fracture of acetabulum, or spavin

Treatment: -

1-Injection of corticoid                                

2-Injection of Lugol’s iodine into and around the bursa

3-Hot Packs over affected area to relieve pain

4-Surgery or injection of irritant is indicated in case of bone or cartilage fracture, or periostitis

Prognosis: -

*Guarded to unfavorable

11-Femoral nerve paralysis or Crural paralysis

Definition: -

Paralysis of quadriceps femoris muscles (rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius muscles), which covers the anterior and side of the femur and inserts into the patella, as a result of injury to the femoral nerve

Etiology: -

1-Azoturia  

2-Trauma                                       

3-Overstretching during kicking

Signs: -

1-Unable to bear weight                              

2-Atrophy of quadriceps muscles in old cases    

3-Flexion of all joints                                  

4-Dificulty in advancing limb (only by flexed hock)

Diagnosis: -

1-History

2-Signs              

3-Examination 

4-Differential diagnosis from;

a-Lateral (true) luxation of the patella (palpation)

b-Rupture of quadriceps femoris muscle (palpation)             

c-Avulsion of tibial crest (radiographs)

Treatment: -

No treatment

1-Rest          

2-Injection of selenium and vitamin E          

3-Massage of muscles to prevent atrophy

4-Mild exercise when partial retention of nerve function is obtained or in case of azoturia

Prognosis:

*Guarded to unfavorable

AFFECTIONS OF THE STIFLE

1-Upward patellar fixation

Definition: -

Permanent or temporary fixation of the patella, over the medial ridge of the femoral trochlea, between the medial and middle patellar ligaments

Etiology: -

1-Bad conformation as straight-leg conformation

2-Overstretching of the patellar ligaments from injury to the leg

3-Sudden taken out of the animal of training and confined to a stall (in equine). The sudden loss of tone of stifle muscles and ligaments allows for increase range of movement of the patella with resultant fixation

4-Excessive contraction of quadriceps muscle during hyperextension of the limb. This may occurs in slipping, jumping, kicking or forcibly pulling out of the limb from a stock.  

Signs: -

1-Hind limb locked with extension of stifle and hock, and flexion of fetlock

2-Catching of the patella especially on short circle turning toward the affected limb

3-Dragging the front of the hoof                                     

4-Low arc of foot flight

5-Short anterior phase stride                                           

6-Snapping sound on release of the patella

7-In chronic cases, presence of gonitis (characterized by excess fluid or thickening of joint capsule) or chondromalacia of the patella

Diagnosis: -

1-History

2-Signs              

3-Examination 

4-Locking of the patella by upward outward forcing 

5-Differential diagnosis from stringhalt (examination, and absence of catching of the patella)

Treatment: -

Medial patellar desmotomy

Medial patellar desmotomy is the treatment of choice. It means transaction of the medial patellar ligament at its tibial attachment. The gait is slightly altered and 3-6 weeks should be allowed for accommodation to the functional loss of this ligament.

-The surgery is performed in standing position but also can be performed in recumbent position.

-The area over the medial and middle patellar ligaments is clipped and prepared aseptically for surgery. Subcutaneous and deep infiltration with 10 mL of 2% lignocaine-hydrochloride was performed over the medial and middle patellar ligaments close to their insertion on the tibial crest. A 2 cm linear incision is made 0.5 cm lateral to the medial patellar ligament near its insertion on the tibial tuberosity. A blunt-end, curved bistoury is inserted vertically. The bistoury is rotated 90 degrees and the distal aspect of the medial patellar ligament is severed with a short sawing motion. The medial patellar ligament could no longer be palpated under the skin. The skin edges are opposed with #2 monofilament nylon

Prognosis: -

*Favorable if it is treated before gonitis

2-Medial and lateral luxation of the patella

This condition is usually met in dog, rarely observed in horse and cattle.

Etiology: -

1-Hereditary predisposition

2-Rupture of the medial or lateral collateral patellar ligament

Signs: -

-Flexion of the stifle joint with inability to put weight on the affected limb.

-The trochlear ridge can be palpated free from the patella

-The patella can be palpated medial or lateral to the stifle joint

Treatment: -

1-The patella can be fixed in its normal place by using silk sutures instead of ruptured collateral patellar ligament

2-Opening of the femoro-patellar joint and rasping of the shallow groove between the trochlear ridges to keep the patella in place

3-Chondromalacia of the patella

Definition: -

Degeneration of the articular cartilage of the patella

Etiology: -

1-Pressing the patella against medial trochlea of the femur during upward patellar fixation, leading to erosion of the surface of the cartilage and gonitis, and in chronic cases, thickening of the stifle joint capsule ensues

2-Trauma to the joint

3-Ligamentus tears like rupture of the anterior cruciate or medial collateral ligaments

Signs: -

1-Gonitis and mild stifle lameness

2-The hip will elevate during trotting similar to hock or stifle lameness

3-Reduced flexion of the stifle and hock                                                

4-Short anterior phase stride

5-Dragging of the toe                                      

6-Thickening and distention of the stifle joint capsule

7-Crepitation or locking of the patella when forced outward upward during extension

8-Mild reaction to spavin test as a result of gonitis

Treatment: -

Remove the cause and reduce inflammation

1-Corticoid injection 

2-Medial patellar desmotomy with 6 months rest for regeneration of cartilage

3-No treatment of advanced cases

Prognosis: -

*Guarded, but if relief ensue after 6 months, the horse may remain sound

4-Gonitis or inflammation of stifle joint

Definition: -

Serous arthritis, osteoarthritis, or suppurative arthritis of stifle joint

Etiology: -

1- Mainly trauma as in: -

-Sprain of medial or lateral collateral ligaments

Mild sprain to sprain fracture predisposing to gonitis. Rupture of the medial collateral ligament causes incapacitation and osteoarthritic changes of the joint, and damage to medial meniscus

-Injury to anterior or posterior cruciate ligaments

Rupture of anterior cruciate ligament predispose to damage of medial meniscus as a result of instability of the joint

-Osteochondritis dissecans (aseptic necrosis)

-Upward fixation of the patella 

It causes gonitis, chondromalacia, and roughening of the medial trochlea of the femur

2-Infectious arthritis: -

-Septicemia in foals with damage to the joint that appears later when the horse put to work

-Penetrating wound

Signs: -

-The medial side of the joint affected more frequently than the lateral part

-Degree of lameness varies according to severity of injury. Lameness is severe when meniscus and cruciate ligament, or collateral ligaments are involved.

-Signs of gonitis (it is swinging and supportive leg lameness)

a-Raised heel                     

b-Forward pushing of the fetlock                

c-Short anterior phase stride

d-Low arc foot flight                                                            

e-Flexion of the stifle during progression     

-Rupture of collateral or cruciate ligaments predisposes to anterior-posterior movement and crepitation of the tibia, and persistent severe lameness

-Exploratory puncture of swollen warm joint will reveal presence of pus (in case of joint ill in foal or suppurative arthritis)

Diagnosis: -

1-History

2-Signs              

3-Examination 

a-Swelling and thickening of the joint capsule 

b-Examination for tearing of collateral ligaments or cruciate ligament

4-Exploratory puncture of warm, painful distention of the stifle indicating suppurative arthritis or navel ill

5-Radiography for horses under 3 year-old for detection of osteochondritis dissecans

6-Mild reaction to spavin test

Treatment: -

1-No treatment if the condition is due to rupture of cruciate or collateral ligaments, or osteoarthritic changes or fracture within the joint

2-Sprain and injury to joint capsule or to ligamentous attachment without rupture can be treated by;

a-Corticoid injection 3 times at week interval, and rest                                      

b-Blistering, firing, or injection of ligaments with irritant like sodium morrhuate

3-If it is suppurative arthritis injection of antibiotic can be attempted

Prognosis: -

*Favorable when gonitis is due to patellar fixation with no chondromalacia

*Guarded to unfavorable in all other cases 

5-Osteochondrosis of tibial tuberosity or Osgood Schlatter disease

Etiology: -

1-Trauma to tibial crest or tension on patellar ligament attached to tibial crest

2-Avulsion of the crest due to upward patellar fixation

Signs: -

1-Sweeling, tenderness, and pain of tibial crest after exercise

2-Trotting like dog as a result of short stride

3-When it is bilateral, short stride and low arc foot in flight cause the toe to be dubbed off

4-Radiographs will show partial avulsion of the crest with bone islets on the cartilage indicating incomplete separation

Diagnosis: -

1-History

2-Signs              

3-Examination 

 4-Radiographs

Treatment: -

1-Rest for 3 months                                              

2-Drilling of tibial crest to induce inflammation

3-Subcutaneous injection of Lugol’s iodine to hasten recovery

Prognosis: -

*Guarded

 

AFFECTIONS OF THE GASKIN AND HOCK

1-Fracture of fibula

It is unusual and rare condition and most of cases blamed to have fracture of the fibula, were merely incomplete fusion of the proximal and distal segments of the fibula

2-Rupture of Peroneus Tertius

Definition: -

It is a rupture of the Peroneus Tertius tendon (peroneus tertius or fibularis tertius) that lies between the long digital extensor and tibialis cranialis muscle. The tendon originates in common with long digital extensor from the extensor fossa of the femur, and inserts on the anterior aspect of the proximal extremity of the 3rd metatarsal bone, and fibular and 4th tarsal bones. The tendon is responsible for flexion of the hock when the stifle is flexed. When it is rupture flexion of the stifle does not cause flexion of hock joint

Etiology: -

1-Overextension of hock joint                                 

2- Rupture is also seen during exertion in a fast start

Signs: -

►During rest

When the limb is put down, horses will have no trouble in bearing weight and show little pain

►During progression

1-Portion of the limb below the hock is carried forward giving the appearance of being fractured

2-Normal flexion of stifle with very little flexion of hock         

3-Dimpling of the Achilles tendon

►Manual examination

4-Dimpling of the Achilles when the limb is lift and extended manually

5-The hock can be extended manually without extension of the stifle

Diagnosis: -

1-History              

2-Signs                  

3-Examination

Treatment: -

-Healing may occur spontaneously by rest for 4-6 weeks, followed by light exercise the next two months

-Tendon suture

Prognosis: -

*Guarded to favorable

3-Rupture of Achilles tendon

Definition: -

Achilles tendon is a convenient name for the aggregates tendons in the distal part of the leg which are attached to the tuber calcis. The structures that comprise the Achilles tendon are the gastrocnemius tendon, superficial flexor tendon, semitendinosus and biceps femoris tendon (tarsal insertion of the last two muscles).

Etiology: -

1-Trauma as kick from another animal                                                              

2-Lacerated wounds

3- Over-stretching of the tendons during jumping

Signs: -

1-Limbs can’t support weight                              

2-Great difficulty in advancing the limb

3-The hock drop to the ground or near it and the hock has excessive angulation

4-Skin and tendon wounds when the cause is sharp trauma

5-Close rupture is characterized by firm painful swelling over the calcaneus

Treatment: -

1- Cast and sling for 2 months                              

2- Carbon fiber implantation in light weight animal

2-Euthansia in old cases

Prognosis: -

*Unfavorable

4-Rupture of gastrocnemius tendon

Apparently, it ruptures before the superficial flexor tendon

Etiology: -

1-Trauma                 

2-Strenuous efforts at stopping        

3-Great stress to extend the hock

Signs: -

1-The horse can walk and the limb can be advanced but with abnormal hock angle

2-Dropping of the hock to the ground with excessive angulation of the hock

3-Inability to straighten the hind limbs when it is bilateral

4-If the entire Achilles is involved the limb can’t support weight

Treatment: -

1-Cast (Thomas splint) and rest with sling                                     

2-Euthansia

Prognosis: -

*Unfavorable

5-Fibrotic myopathy and ossifying myopathy

Definition: -

Old injury to semitendinosus, semimembranosus, and/ or biceps femoris muscles, leading to adhesion between semimembranosus and semitendinosus medially, or semitendinosus and biceps femoris muscles laterally

A-Fibrotic lesion of semitendinosus is the most important as a result of adhesion between it and semimembranosus and biceps femoris muscles, which limits the action of semitendinosus leading to abnormal gait 

B-Ossifying myopathy is an ossification (metaplasia of fibroblasts to osteoblasts) of fibrotic myopathy lesion with the same signs of lameness as fibrotic myopathy, and it can occur in the forelimb

Etiology: -

Trauma 

Signs: -

1-The lameness is not clear during walking

2-The affected limb is suddenly pulled posteriorly 7-10 cm, during anterior phase of stride, before contacting the ground

3-Short anterior phase of stride

4-Presence of area of firmness at the posterior surface of the limb at the level of stifle joint and above it

Diagnosis: -

1-Signs                 

2-Examination 

3-Diffrential diagnosis from stringhalt (anterior pulling of the limb toward the abdomen)

Treatment: -

Surgical removal of 10 cm of semitendinosus tendon (5 cm from the tendon and 5 cm from the muscle) at the level of stifle and this portion should be removed at the junction of the muscle belly before the tendon divides. Then the adhesion between muscles should be separated

6-Stringhalt

Definition: -

Involuntary flexion of the hock during progression. The condition may affect one or both hind limb

Etiology: -

1-Nervous disease, degeneration of sciatic and/ or peroneal nerves, or affection of spinal cord

2-Involvement of the lateral digital extensor

a- Trauma                               

b- Adhesion as the tendon crosses the lateral surface of the hock

Signs: -

1-Mild flexion of the hock to severe jerking of the foot toward the abdomen (anterior surface of fetlock hits the abdomen) during progression. It may be in every step or spasmodic

2-Signs increase with cold weather and decrease with warm one

Diagnosis: -

1-Signs 

2-Differential diagnosis;

a-Upward patellar fixation (locking and releasing of patella when forced upward and outward on trochlea)    

b-Fibrotic myopathy (sudden downward backward jerking of the foot before being put to ground)

Treatment: -

Surgical removal of a portion of the lateral digital extensor tendon from just above the lateral malleolus of the tibia to just before it joins the long extensor

Prognosis: -

*Guarded to favorable

7-Shivering

Definition: -

Involuntary muscular movement of both hind limb and tail

Etiology: -

Unknown, may be nervous or neuromuscular disease

Signs: -

Difficult to be detected in mild cases as it occurs at irregular intervals

1-When attempts are made to back the horse, he will jerk the hind foot from ground and hold it in flexed abducted position

2-Limb shakes violently while the tail is elevated and quivers, for short time, then return to normal. Signs recur on re-backing of the animal 

3-Same signs may occur for some horses when they turned, forced to step over an object, or the foot is raised from the ground by hand

4-The eyelids and ears may flicker and the lips may be drawn backward

5-If the forelimbs are involved, the limb will be raised, abducted, and the carpal will be flexed, and muscles above the elbow will quiver until signs disappear

Treatment: -

No treatment

Prognosis: -

*Unfavorable as the signs increase over the time

8-Bone spavin

Definition: -

Osteoarthritis (progressing to ankylosing arthritis with osteitis and periostitis) usually affects the medial aspect of proximal end of 3rd metatarsal and medial aspect of 3rd and central tarsal bones. It causes ankylosis of distal intertarsal and tarsometatarsal joints

Jack spavin is a bone spavin of large proportions

High spavin is bone spavin of higher location than ordinary site

Etiology: -

1-Poor conformation like sickle hock or cow hock (that predispose to great stress on medial aspect of hock joint), or narrow and thin hocks

2-Trauma, especially that produced by quick stops                                          

3-Miniral deficiency or imbalance

Signs: -

1-Periodinc flexion of the hock in spasmodic manner during rest

2-Lameness is clear at beginning of work and the animal warm out of lameness if it is mild spavin, but if it is severe spavin, lameness increase with exercise

3-Low arc of foot flight (improper flexion)                                            

4-Short anterior phase stride

5-Landing on outside of the toe and wearing of outside of toe due to dragging (as the horse attempts to place most of weight on outside of the foot to relieve pain) leading to low toe and high heel             

6-Hiking             

7-New bone growth and enlargement on medial aspect of the hock

8- The spavin test (trotting after hock flexion for 60 sec) may be a useful aid to diagnosis but is not specific for this condition or even this joint

Diagnosis: -

1-History

2-Signs                                                   

3-Examination                   

4-Blocking posterior tibial and deep peroneal nerves

5-Articular analgesia of lower tarsal joints               

6-Radiographs

7-Differential diagnosis from;

a-Gonitis or affections of stifle (by careful examination)

b-Enlarged head of 2nd metatarsal bone (palpation, location, and radiographs)

Treatment: -

The best results can be obtained after ankylosis

1-Cunean tenectomy: removal 2-4 cm of cunean tendon (the medial insertion of tibialis cranialis muscle), followed by 2 months rest. It removes the pressure of the tendon on the affected area

3-Blistering, but it is useless as it causes superficial inflammation

4-Firing into distal tarsal bones with or without previous cunean tenectomy, to stimulate ankylosis

5-Neurectomy of posterior tibial and deep peroneal nerves

6-Corrective shoeing: Raise the heels (swaged-up heel) and roll the toe

7-Arthrodesis: destroys the cartilage in the joint to initiate new growth between the upper and lower bones of the joint. At least 60% of the articular cartilage should be destroyed.

Prognosis:

*Guarded always                             

*Unfavorable in case of bony changes in tibiotarsal articulation

9-Bog spavin

Definition: -

Chronic distention of tibiotarsal joint capsule leading to formation of 3 swellings, one on the anteriormedial aspect of the hock, and one on either side of the posterior surface of the hock at the junction of the tibial tarsal and fibular tarsal bones 

Etiology: -

1-Faulty conformation (straight behind)    

2-Miniral and vitamin deficiency (up to 6-24 month old)

3-Trauma

a-Quick stops or quick turns   

b- Injury to joint capsule or tarsal ligament

c- Chip fracture of hock joint (unilateral)

d- Osteochondritis dissecans (unilateral)

Signs: -

1-Lameness is clear if spavin is traumatic (with heat and pain), or due to osteochondritis dissecans

2-Three fluctuating swellings, one on the anteriormedial aspect (usually the largest) and one on either side of the posterior surface of the hock at the junction of the tibial tarsal and fibular tarsal bones. Level of these swellings is lower than thoroughpin, and application of pressure on any of them causes increasing in the size and tension of the other two swellings

3-No bone change in uncomplicated bog spavins, either manually or radiologically

Diagnosis: -

1-History

2-Signs                         

3-Examination                          

4-Radiographs for detection of chip fracture 

Treatment: -

Only those of traumatic or nutritional origin, can be treated

1-When it is traumatic with no fracture, it can be treated by 3 corticoid injections, week interval, into the anteriormedial swelling, followed by pressure bandage and rest for 3 weeks after subsidence of lameness

2-When it is chronic, it can be treated by blistering, firing, or subcutaneous injection of irritants, but the later may predispose to suppuration

3-Nutritional cases can be treated by correction of diet and cure will ensue 4-6 weeks later on

Prognosis: -

*Guarded in traumatic and nutritional cases

*Unfavorable in case of bad conformation

10-Blood spavin

Enlarged saphenous vein crossing bog spavin

11-Occult spavin or blind spavin

Definition: -

Disease originally within the hock joint, causes typical spavin lameness, shows no palpable or radiological changes, and it is the least common form of spavins

Etiology: -

1-Trauma 

2-Intra articular lesion that is not evident in radiological examination 

a-Ulcer of articular cartilage                          

b-Injury to small interosseous ligament of tarsal bones

Signs: -

Same as bone spavin with no physical changes

1-Low arc of foot in flight (improper flexion)                                    

2-Short anterior phase of stride

3-Draging of the toe leading to wearing of the toe of the hoof wall

4-Same rolling action of the hip as bone spavin                                 

5-Positive spavin test

6-No physical or radiological changes

Diagnosis: -

1-History

2-Signs                         

3-Examination                         

4-Differential diagnosis from

a-Bone spavin (by physical changes and radiology)       

b-Bursitis of cunean tendon                     

c-Gonitis

5-Block anesthesia by peroneal and tibial nerve block, and block of the lower tarsal joint

Treatment: - 

Treatment is too difficult as the lesion is not evident radiographically

1-Injection with corticoid and rest

2-Blistering and firing of joint or cunean tenotomy are of no value

3-Surgical arthrodesis of distal tarsal and tarsometatarsal joints, if it is early bone spavin

Prognosis: -

*Unfavorable to guarded

12-Chip fracture of the tibial tarsal bone

Definition: -

Fracture either in one trochlea or in the portion of the bone articulating in the proximal intertarsal joint, or in the distal end of tibia

Etiology: -

1-Sever stress on the hock joint                    

2-Osteochondoritis dissecans of the trochlea

Signs: -

1-Same as bog spavin            

2-Variable lameness (none to severe)

Diagnosis: -

1-History

2-Signs                         

3-Examination                         

4-Radiographs (differentiation between bog spavin, fracture, or osteochondritis lesion of tibial tarsal bone)

Treatment: -

1-Surgical removal of small fragment according to location

2-Surgical fixation of large fragment near distal aspect of the bone

3-Rest in case of osteochondritis dissecans with no avulsion

Prognosis: -

*Favorable when fragment doesn’t involve the articular surface of trochlea

*Guarded to unfavorable in all cases 

13-Thoroughpin (tenosynovitis or tenovaginitis)

Definition: -

Tenosynovitis of tarsal sheath enclosing the deep digital flexor tendon

Etiology: -

1-Trauma (unilateral)                

2-Hard work (mild bilateral swelling - classified as wind puff)

Signs: -

Small to large swelling at a level approximately the same as that of point of the hock

Diagnosis: -

1-Signs and examination

2-Differential diagnosis from bog spavin that causes swellings on medial and lateral sides of hock joint 5 cm lower than location of thoroughpin (swelling of the tarsal joint capsule)

Treatment: -   

1-Injection with corticoid 2-3 times weekly                 

2-Contraindicated to make blistering or firing

14-Bursitis of cunean tendon

Signs: -

1-Lameness of hock similar to bone spavin                  

2-Swelling of bursa over cunean tendon

Diagnosis: -

1-Signs and examination                                 

2-Local analgesia for differentiation from spavin

Treatment: -  

Cunean tenectomy

15-Curb

Definition: -

Enlargement at the planter aspect of the fibular tarsal bone due to inflammation and thickening of the planter ligament

Etiology: -

►1-Predisposing factors

Appear few days after birth as sickle hock or curby hock

►2-Exciting factors

a-Violent exertion                

b-Trauma and kicking         

c-Violent extension of hock

Signs: -

► A-Acute cases

1-Enlargement on planter surface of fibular tarsal bone over the planter ligament

2-When it is accompanied with suppuration the swelling increases with cellulites in the surrounding areas

3-Swelling doesn’t reduced with exercise and lameness increased

4-Periostitis with new bone growth in that area (in traumatic cases)

5-Lameness and signs of inflammation                     

6-Rising heel on rest

► B-Chronic cases

1-Scar tissue in the surrounding                 

2-Permanent blemish                      

3-No lameness

Diagnosis: -

1-Signs and examination                                  

2-radiographs

2-Differential diagnosis from enlarged head of the 4th metatarsal

a-Examination reveals swelling lateral to planter ligament not on it                   

b-Radiographs

Treatment: -  

► A-Acute cases

1-Local corticoid (no infection), rest, cold application, and bandage

2-Cold application and antiphlogistic

► B-Chronic cases

Blister or firing (not before 10 days of appearance)

Prognosis: -

*Favorable if it is not congenital and inflammation respond to corticoid injection

*Unfavorable if it is congenital

16-Capped hock (Bursitis of the hock)

Etiology: -

Trauma (acquired) & kicking

Signs: -

1-Firm swelling at the point of hock                   

2-Mild lameness                  

3-Permanent blemish

4-May be associated with curb (extensive with edema when it is severe)

Treatment: -  

► A-Recent cases

Injection of corticoid into the cavity and tissue for several times a week, after withdrawal of synovia, and application of pressure bandage

► B-Fibrosed or large blemishing cases

Surgical removal with lateral incision, cross tying, and bandage

17-Weak flexor tendons

Definition: -

Congenital weak flexor tendons that may allow the fetlock to hit the ground and the toe will be off the ground

Etiology: -

Congenital

Signs: -

Mild to severe and may be associated with sickle hocks

Treatment: -   

1-The limb may be strengthen in few days without treatment

2-Support the foot with trailer shoe by ordinary triangular door hinges (12 cm long) one on medial and one on lateral sides of the foot. Bandage by plaster cast to the hoof wall for few days. Flat steel piece 5 cm X 12 cm X 4mm

Prognosis: -

*Favorable in fetlock that hasn’t been injured