Ligaments, luxations, arthrodesis Flashcards
Ligament and tendon structure
Both ligaments and tendons are composites of collagen type I (98%) in a proteoglycan matrix produced by fibroblasts
Tendon blood supply is more resilient as it comes from multiple sources, not just the insertion sites
Tendons
Join muscle to bone
Tough, inelastic
Continuous sheets of fibroblasts with matrix
Fibres in dense, parallel bundles
Ligaments
Joins bone to bone
Strong, elastic
Scattered fibroblasts in matrix
Fibres not arranged in parallel fashion
Healing of tendons and ligaments
Poor blood supply
Heal by formation of scar tissue
Requires initial protection
Followed by controlled mobilisation
Regain around 60% of strength by 6 weeks
Susceptible to re-injury
Orthotics can be invaluable in managing these injuries
Type I ligament sprain
Minimal tearing with some internal haemorrhage
Rest, bandage for 2 weeks
Type II ligament sprain
Partial tearing and stretching of fibres with intrenal and peri-ligamentous haemorrhage
Surgical repair (suture ligament or protect with prosthetic)
External coaptation post op
Type III ligament
Complete rupture or avulsion of attachment
Surgical repair and prosthetic replacement
ESF or cast post op
Arthrodesis indicated in some cases
Common ligament injuries
Cruciate ligaments
Collateral ligaments
Round ligament of the femoral head
Plantar ligament injuries
Carpal ligament injuries
Collateral ligament injuries
Usually traumatic, usually severe
Seen in shoulder, elbow, carpus, stifle, hock, and interphalageal joints
May present with obvious instability or joint luxation
In the shoulder can present as lameness without obvious instability
Investigations of ligament injury
Assessment of stance and gait
Sedated exam of joint stability
Survey radiographs and stressed radiographs
Management of ligament injury
Isolated tears of the medial or lateral collateral ligaments repaired by primary repair or prosthetic replacement
Post operatively apply rigid external coaptation
Prostetics for ligament injury
Prosthetics can be placed using two screws, washers and a figure of eight wire or synthetic monofilament suture such as nylon or polypropylene.
Or alternatively by use of a suture anchor system instead of screws.
Open ligament injuries
Commonly major trauma
Usually affect the distal limb joints
Treatment must allow simultaneous management of the ligament and skin injuries
ESF can be very useful - immobilises the joint
Arthrodesis
Permanent rigid fusion of a joint
Salvage procedure
Indications for arthrodesis
Unrelenting chronic pain from DJD that is not treatable by other means
Untreatable fractures
Chronic joint luxations
Partial neurological injuries
Unreconstructable ligament injuries or instability
Arthrodesis as a salvage procedure
Allows a continuation of the function of the animal, or part of animal, wothout preservation of normal anatomy
Which joints can be arthrodesed?
Distal joints: carpus > tarsus
Elbow and stifle will lead to signifcant gait alteration -> long lever arm -> problems!
Contraindicated in the hip
Can do well after shoulder arthrodesis
How to achieve arthrodesis
Debridement of cartilage
Placement of CBG
Immobilisation of the affected joint
Stabilisation at an appropriate angle
Arthrodesis after plantar/palmar ligament rupture
If there is degeneration or rupture of the plantar or palmar ligaments or fibrocartilage of the tarsus or carpus then repair of these ligaments / fibrocartilage is not usually successful and arthrodesis is the treatment of choice.
Implants used to stabilise the joints vary according to the level of injury.
Calcaneoquartal joint injury (proximal intertarsal subluxations)
A plate applied to the lateral aspect of the tarsus – (from the os calcaneus to the metatarsal bones).
Or a pin and figure of eight tension band wire (8 TBW)
Tarsometatarsal luxations
Lateral bone plate or 2 screws or K wires placed in a cross pin fashion with a figure of 8 TBW
Post-operative management of arthrodesis
Generally some form of external coaptation (cast or splint) should be used for a period of 4-8 weeks post operatively until radiographic evidence of healing is documented.
Prognosis of arthrodesis
With arthrodesis of any of the joints distal to the talocrural (tibiotarsal joint) then the prognosis is good.
Implants may occasionally need removal because of the limited soft tissue coverage in this area.
Arthrodesis after plantar tarsal ligament rupture necessitates a PARTIAL tarsal arthrodesis.
Carpal hyperextansion injuries
Little support from bony integrity.
Ligaments and palmar carpal fibrocartilage are the main supporting structures.
Hyperextension is usually secondary to trauma but can also occur secondary to immune mediated diseases such as rheumatoid arthritis.
The palmar LIGAMENTS and fibrocartilage are the structures most commonly damaged.
Diagnosis of carpal hyperextension injuries
Survey radiographs may show soft tissue swelling, and avulsion fractures.
In chronic injuries evidence of osteoarthritis may be present.
Stressed radiographs are needed in most cases to determine the level of injury.
Radiographs are taken with the carpus stressed in a hyperextended position.
Compare with the opposite limb.
Incidence of carpal joint hyperflexion injuries
ntebrachiocarpal joint – least common
middle carpal joint
carpometacarpal joint - commonest
Treatment for carpal hyperflexion injuries
Arthrodesis
- partial (fusion of middle carpal joint and carpometacarpal joint)
- pan (fusion of all three joint levels)
Plantar ligament rupture
Sometimes traumatic
Also seen in Shetland sheepdogs with no history of trauma, often bilaterally
Treatment of plantar ligament rupture
Tarsal arthrodesis
- partial
- pan
Congenital shoulder luxation
This is an uncommon condition seen only sporadically in
Small breed dogs - toy poodles and shelties
The luxation is commonly medial
The condition may be bilateral.
Clinical signs of congenital shoulder luxation
Present with an abnormal gait when they are several months of age
Diagnosis of congenital shoulder luxation
Mediolateral and craniocaudal radiographs necessary to confirm
In advanced cases the glenoid may be flattened or even convex in shape
Treatment of congenital shoulder luxations
In early cases attempts to reduce the luxation and place a small temporary transarticular pin may be successful.
In more advanced cases then either arthrodesis or excision of part of the glenoid and part of the humeral head to allow a pseudoarthrosis to develop is generally successful.
Some cases can be treated conservatively
Congenital elbow luxation
Uncommon
Campbells classification
Surgical reduction is sometimes possible
Type I elbow luxation
Caudolateral dislocation of the radial head
Probably developmental
Most common in chondrodystrophic breeds
First seen at 4-6months
Usually premature closure of the distal ulna growth plate
Treatment of type I elbow luxation
Three options
○ osteotomy of the ulna,
○ ostectomy of the radius,
○ radial head excision.
Sometimes deformity can be severe, osteotomys of both bones are required; and the prognosis is guarded.
Type II elbow luxation
Lateral dislocation of the ulna
Congenital
Recognised within several weeks of birth
Lateral displacement results in an inability to extend the elbow
Treatment of type II elbow luxation
Reducing the ulna manually and placing a transarticular pin across the joint for 10 to 14 days,
using pins and elastic bands to dynamically reduce the luxation.
The prognosis is guarded for formation of a normal joint but function is usually adequate after treatment.
Type III elbow luxation
Dislocation of both radius and ulna laterally
A more severe luxation and treatment is similar as for type II although the prognosis is more guarded
Acquired luxations
Usually occur after significant trauma
Significant soft tissue damage has to occur to allow a joint to dislocate
There will be ligament ruptures (collaterals) and in severe cases there may be muscle or tendon ruptures as well
Acquired shoulder luxation - breeds affected
Any
Whippets may be over-represented
Acquired shoulder luxation - cause
Fall, knock, dog fight, RTA
Acquired shoulder luxation - presenting signs
Often acute onset severe non weight bearing lameness
Acquired shoulder luxation - physical examination
Limb carried in a flexed position, pain, and crepitation on manipulation
Acquired shoulder luxation - diagnosis
2 orthogonal x-ray views
Check for concurrent trauma e.g. pneumothorax, fractures
Treatment of Acquired shoulder luxation
Closed reduction or surgical reduction
Closed reduction of Acquired shoulder luxation
dog anaesthetised
attempt prior to surgery
Lateral luxations: with leg extended apply medial pressure to humerus and lateral pressure to scapula, if reduction stable through a normal ROM then support with a spica splint for 10 -14 days.
Medial luxations - reduce by extending leg and apply lateral pressure to the proximal humerus and medial pressure to the distal scapula, if reduction stable through a normal ROM then support with a velpeau sling for 10-14 days.
Surgical treatment of acquired shoulder luxation
if closed reduction is unsuccessful then open reduction and stabilisation with capsulorrhaphy or tendon transposition is required
In severe cases with dysplasia or DJD then salvage procedures such as glenoid excision or arthrodesis must be performed.
A surgical approach is made to the joint and the articular surfaces are inspected.
*If the labrum is worn then the prognosis for successful stabilisation is poor.
Prognosis for acquired shoulder luxation
fair, DJD may develop.
Dislocation of the scapula
Very rare
Occurs secondary to severe trauma
Disrupts the attachment of the scapula to the thoracic wall
May be commoner in cats than dogs
Relocated using a heavy gauge wire placed through a small hole in the caudal border of the scapula
Aquired elbow luxation
Traumatic luxation of the elbow is not common.
However when it occurs the direction of the luxation is usually lateral as the medial aspect of the condyle is larger and slopes distally making medial luxation very unlikely.
Acquired elbow luxation - signalment
Any
Acquired elbow luxation - cause
Often trauma e.g. RTA
Acquired elbow luxation - clinical presentation
Non-weight bearing lameness with adduction of the elbow, abduction of the foot and pronation of the foot
Elbow swelling usually present and ROM severely limited
Acquired elbow luxation - investigation
radiography (orthogonal views)
check for the presence of fractures
Acquired elbow luxation - treatment
Attempt closed reduction
If closed reduction successful assess collateral ligament inetgrity
If not successful then attempt surgical repair - primarily using a suture technique like the locking loop pattern
Acquired elbow luxation - post op
Leg should be supported in an extended position using either a bandage up to the axilla or preferably a body bandage or spica splint
External coaptation should not be used for more than 2 weeks or severe stiffness of the elbow joint will result
Acquired elbow luxation - prognosis
after closed reduction alone the prognosis is good with 90% of dogs returning to normal.
The prognosis is worse after surgical reduction (usually the chronic or more severe cases) with only 50% returning to normal and the other 50% staying intermittently or permanently lame.
Monteggia fractures
These are elbow luxations that occur concurrent to fractures of the ulna.
The annular ligament AND interosseous ligament may both be damaged.
The ulna fracture must be repaired.
Reluxation is a common complication secondary to the ligament instability.
It is important to repair/replace the annular ligament or fixate the radius to the ulna (either temporarily or permanently) to minimise the likelihood of reluxation.
Hip luxations
Hip luxations most commonly occur in a cranio-dorsal direction, ventral or caudal luxation is much less common.
Medial luxation may occur in combination with an acetabular fracture.
Diagnosis of hip luxation
Gait: affected animals will be non-weight bearing or markedly lame on the affected limb
Thumb displacement test negative - the thumb will not be displaced if the hip is dislocated craniodorsally
Radiography
Closed reduction for hip luxations
animals should preferably be anaesthetised (or very heavily sedated).
Reduction is achieved by extension of the hip followed by internal rotation of the hip.
A palpable or audible click should be felt when the hip is reduced.
Reduction should be confirmed with further radiography.
Cage confinement or placement of an Ehmer sling should then be used to prevent reluxation.
Why might closed reduction of a hip luxation fail?
Hip dysplasia
Femoral head fracture fragments
Blood clot, fibrous tissue, or infolding of the joint capsule in the acetabulum
Inadequate restriction of exercise post reduction
Indications for surgical reduction of hip luxation
Articular fractures are present
The luxation is chronic
There are other injuries present
Closed reduction is unsuccessful
The joint reluxates
Salvage surgery of hip luxation
(femoral head and neck excision or total hip replacement) should be considered if there is underlying hip dysplasia.
Primary repair of hip luxation
Open reduction, debridement (of ruptured round ligament and fibrin in the acetabulum) and repair of the joint capsule with non-absorbable or slowly absorbable suture material.
Prosthetic (synthetic) capsule technique
after debridement of the acetabulum and reduction of the femoral head two screws & spiked washers (latter to prevent sutures slipping off) are placed in the acetabulum
Sutures are then placed through a hole drilled in the greater trochanter and looped around the screws.
This technique is useful for large and medium sized dogs.
Transarticular pinning for hip luxation
a suitable size intramedullary pin or K wire is driven from the fovea capitis laterally through the neck to exit the lateral femoral cortex distal to the third trochanter.
Following hip reduction the pin is driven through the acetabular wall and 5-6mm into the pelvic canal.
The pin is then cut short but left long enough for ease of removal later.
Post operative exercise reduction (or an Ehmer sling should be applied) and the pin can be removed 2-3 weeks later.
This technique is no longer recommended due to pin breakage and migration.
Iliofemoral suture for hip luxation
after hip reduction a hole is drilled through the pelvis just cranial to the hip at the origin of the rectus femoris muscle.
Another hole is drilled across the greater trochanter.
Suture material (50,80 or 100lb monofilament nylon leader line) is passed through the holes and tied or secured with crimps with the hip held in a internally rotated and slightly abducted position.
Hip toggle for hip luxation
the hip is kept reduced with a toggle pin, placed through a hole in the acetabulum to the medial aspect of the acetabulum and secured with strands of suture fed through a hole in the femural head and neck .
After hip reduction the suture strands are tied around a button along the lateral femoral cortex.
The hip has, postoperatively, a full range of movement, however, as the suture is placed into a very hostile abrasive environment, it will fail eventually.
Prognosisof hip luxation
with closed reduction the success rate is 17-75% (depending on whose paper you read! The success rate after surgery is also variable but around 85% successful.
If the luxation is chronic or recurrent and there is articular cartilage damage then arthritis may develop and a permanent lameness may result.
Salvage options such as FHNE or a THR may have to be considered.
Stifle disruption
multiple ligamentous injury can be seen after severe trauma or catching the foot in a fence.
Most commonly both cruciates and one collateral ligament are ruptured.
Also called stifle derangement.
Stifle luxation - history
non weight-bearing lameness after severe trauma (RTA) or catching a foot in a gate whilst jumping.
Stifle luxation - physical examination
in acute stages the stifle joint will be swollen and painful.
A thorough examination should be carried out with the animal anaesthetised.
Stifle luxation - investigations
examination for instability under anaesthesia – perform cranial draw, varus and valgus stress tests.
Take survey radiographs and stressed radiographs to demonstrate instability.
Comparison with the opposite stifle may be useful.
Stifle luxation - treatment options
surgical repair is usually indicated.
Primary repair of ruptured ligaments is often not possible so a prosthetic replacement is required using polydioxanone (PDS™) or nylon anchored through bone tunnels or around screws and washers.
Wire can be used to splint the repair.
The suture material will likely fail eventually but peri-articular fibrosis will hopefully be sufficient by the time this occurs.
Stifle luxation - post op care
With severe disruption then post-operative external coaptation should be provided with a cast, splint, or ESF for 4-6weeks.
Stifle luxation - prognosis
Variable.
At best a reduction in ROM, and some stiffness will generally result at worst the animal will be permanently lame or non-weight bearing on the limb.
In working animals the prognosis is guarded for an adequate return to function.
Luxation of the metacarpophalangeal joints or interphalangeal joints
Seen most commonly in greyhounds.
The collateral ligaments will be damaged and these need repair using locking loop or mattress sutures of non-absorbable suture material.
Small avulsion fractures can be repaired using a lag screw or wire mattress suture.
Post-operative support in the form of bandaging should be applied for 2-4 weeks post operatively.
