Lecture 10: Collateral and Multiple Ligament Injury/Meniscal Injury

collateral ligament injury

complete or partial tear of medial or lateral collateral ligament

ligament injury =

sprain

muscle tendon unit =

strain (no grading)

what is the function of the medial and lateral collateral ligament?

limit varus-valgus motion of stifle joint

injuries to medial or lateral collateral ligaments occur with

injury to other primary and secondary restraints of stifle joint

multiple ligament injuries result from

severe trauma to stifle joint

PE findings for collateral ligament injury

• based on palpation

• stifle joint extended to examine for collateral injury

the valgus stress test evaluates the

medial collateral ligment

the varus stress test evaluates the

lateral collateral ligament

valgus stress test

• patient in lateral recumbency

• one hand stabilizes femur while other hand grasps distal tibia and applies upward force (abduction)

• if medial joint restraints are torn → see opening of medial joint line

varus stress test

• patient in lateral recumbency

• one hand stabilizes femur while the other hand grasps distal tibia and applies inward force (adduction)

• if lateral restraints are torn → see opening of lateral joint

radiographs for collateral ligament tear

determines if bone fragments are associated with ligament damage

craniocaudal and medial-lateral radiographs confirm

presence of absence of bony avulsions

what is this showing?

valgus stress applied to joint → MCL injury

differential diagnosis for collateral ligament tear

• muscle strains

• cranial or caudal cruciate ligament tears

• nondisplaced physeal fractures in immature animals

conservative or surgical treatment for isolated collateral ligament injury is based on

degree of injury

what is an indication for conservative treatment/1st degree sprain?

minimal swelling and only slight opening of joint space with stress test

what indicates greater injury to collateral restraints/2nd to 3rd degree sprains?

moderate to severe swelling and significant opening of joint space with stress test

surgical treatment for 2nd or 3rd degree sprains?

reconstruction of collateral ligaments, meniscocapsular ligaments, and joint capsule

primary repair of collateral ligaments is done if

• point of failure is origin or insertion of ligament

• an intrasubstance tear with large segments of ligament intact

preoperative management to prevent additional damage to articular cartilage or menisci

• place modified robert jones bandage on limb

• limit activity to leash walking

preop management for patients with injuries by HBC

thoracic, cardiovascular, and abdominal evaluation

perioperative antibiotics and preemptive pain management

• NSAIDs

• opioids

• epidural analgesia

medial collateral ligament anatomy

• originates from medial femoral epicondyle

• runs distally to insert onto proximal tibial metaphysis

• as ligament crosses medial joint line → strong attachment to joint capsule and medial meniscus

• lies deep to caudal sartorius muscle

lateral collateral ligament anatomy

• originates from oval area on lateral femoral epicondyle

• runs distally to insert onto fibular head

• lies deep to fascia lata

what do you need to preserve when dissecting near the lateral collateral ligament?

peroneal (fibular) nerve

peroneal nerve

• branch of sciatic nerve

• obliquely crosses distal aspect of stifle joint

• superficial to gastrocnemius muscle

• sends articular branch to lateral collateral ligament

patient positioning for lateral collateral ligament injury

lateral recumbency with affected leg up

patient positioning for medial collateral ligament injuries

dorsal recumbency

patient positioning for multiple ligament tears

• dorsal recumbency to facilitate exposure to both sides of limb

• suspend limb and prepare for aseptic surgery

where should the incision go for repair of a medial restraint injury?

the insertion of the caudal head of sartorius muscle and deep fascia along craniomedial border of proximal tibia

if ligament injury is intrasubstance tear

• primary repair by suturing ligament ends with locking-loop suture pattern

• supplement primary repair with screws and figure-eight support

repair of a lateral restraint injury

• craniolateral approach to expose lateral collateral ligament

• make proximal to distal parapatellar incision through fascia lata

• continue incision distally 4cm below tibial crest parallel to joint line → protect peroneal nerve

• reflect fascia lata caudally → expose collateral ligament and lateral joint capsule

• repair ligament as described for MCL

prognosis for isolated collateral ligament tears

good to excellent

prognosis for multiple ligament tears

fair

multiple ligament injuries

• injuries where cranial or caudal cruciate ligaments and collateral ligaments are damaged simultaneously

• caused by HBC or other major trauma

surgical anatomy of multiple ligament tears

• moderate to severe swelling and bruising of soft tissue surrounding joint seen

• torn collateral ligaments difficult to identify because often encased in edematous connective tissue

• menisci often displaced from normal positions and folded cranially or caudally

what structures are commonly injured with multiple ligament derangement of the stifle joint?

cranial and caudal cruciate ligaments and disruption of the medial restraints

common triad of multiple ligament injuries include

• cranial and caudal cruciate ligament tears

• failure of primary and secondary medial restraints

• peripheral medial meniscal tears

deranged stifle

• when there are multiple ligamentous injuries

• often with meniscal injury → resulting in luxation of stifle joint

locations of release of medial meniscus

• transection of meniscotibial ligament

• transection of midbody of meniscus

meniscal release

• means of protecting medial meniscus following surgical stabilization of stifle

• developed in association with TPLO

• uncertain efficacy

by transecting the meniscus, the function of the meniscus is

compromised by elimination of hoop stresses

midbody release or transection of meniscotibial ligament

• femoral condyle increases contact with articular cartilage of tibial plateau → contributes to OA

• impairs functions of meniscus to provide stability and congruence

no clinical studies demonstrate efficacy of meniscal release in

decreasing incidence of post TPLO meniscal injury, but technique remains in widespread use

why is conservative treatment not an option for meniscal injuries?

• continued back and forth sliding of torn meniscus → causes severe pain, will not improve

• accelerates DJD

methods of surgical treatment for meniscal injuries

• partial meniscectomy

• primary repair of peripheral meniscal injuries

• total meniscectomy

medial meniscectomy is easiest to perform through a

medial surgical approach

partial meniscectomy

• removal of torn section of meniscus

• experimentally → carries less morbidity than a total meniscectomy

• treatment of choice for bucket handle tears of medial meniscus

primary repair of peripheral meniscal injuries in dogs

• reserved for peripheral tears

• uncommon

total meniscal removal induces

severe DJD in stifle

total meniscectomy

• considered only when peripheral rim of meniscus is so damaged that primary suturing of meniscocapsular tissue not possible

• the more meniscal tissue removed, the more rapidly OA develops