Ligament Injuries Flashcards
ACL PCL MCL LCL PLC Knee dislocation Proximal tibfib dislocation
Describe the epidemiology of acl injuries?
- Mechanism is non contact pivoting injury
- Often assoc w meniscal injury
- 50% lateral meniscal tear w acute acl injury
-
>female athelete 4.5:1
- neuromuscular forces ( more quads dominant)
- Landing biomechnics- females land in >extension, higher valgus moment
- Genetics= COL5A1 gene assoc w reduced risk ACL tears
- smaller ligaments
- hormone levels
What are chronic ACL deficient knees assoc with?
- Chondral injuries
- Complex unrepairable meniscal tears
- relation with arthritis is contraversial
Describe the ACL anatomy?
- Provides stability to prevent anterior translation of tibia cf femur
- 2 bundles
- anteriomedial- tight in flexion
- posteriolateral- tight in extension, contributes most to rotational stability
- Blood supply - Middle geniculate artery
- innervation- Post articular nerve
- Composition
- 90% type 1 collagen
- 10% type 2 collagen
Describe the presentation of an ACL lig injury?
- Presentation
- felt a pop
- pain deep in knee
- immediate swelling 70%- haemarthrosis
- O/E
- effusion
- quads avoidance gait- dont’actively extend knee
- Lachman test
- a= firm endpoint, B= no endpoint
- grade1 <5mm translation
- grade 2 5-10 mm translation
- grade 3 >10mm translation
- PCL may give false lachman test due to posterior subluxation
- Pivot shift
- extension, int rotation and then flexion
- lateral tibia is subluxed anteriorly, when flexed to 30 degree spontaneously reduces- due to IT band changing from extensor to flexor moment at knee
- mimics the actual giving way
What is seen on xray of ACL Iiagment injury?
- Xrays
- usually normal
- Segong fx - avulsion fx of prox lateral tibia
- usually normal
What is seen on MRI of ACL injury?
- tear best seen on Sagittal view
-
bone brusing occurs in > 1/2 acute ACL tears
- middle 1/3 of LFC ( sulcus terminalis)
- Posterior 1/3 of lateral tibial plateau
What is the tx for ACL?
- Non operative
- Physio and lifesyle modifications
- low demand pts
- increased meniscal damage linke dto
- loss of meniscal integrity
- freq of buckling episodes
- level 1/11 activity- jumping, heavy manual labour
- Physio and lifesyle modifications
Operative
- ACL reconstruction
- younger more active ( reduces risk of chondral /meniscal injury)
- prior acl repair
- children
- _ w assoc MCl injury_
- allow mcl to heal then preform ACL recon
- varus/valgus instability can jeopardise graft
-
w assoc Meniscal tear
- preform mensical repair same time as ACL
- increased healing rate when repaired together
-
w assoc Postlat corner injury
- reconstruct same time as ACL or 1st as 2 stage revision
- Ligament Repair- hgh failure rate
-
Revision acl reconstruction
- failed prior acl recon
Describe the technique of acl reconstruction?
-
Femoral tunnel placement
- sagittal plane
- 1-2mm of rim bone between tunnel and post cortex of femur
- coronal plane
- at 9-10 o’clock position lateral wall- more horizontal graft
- sagittal plane
-
Tibial Tunnel placement
- sagittal plane
- centre of tunnel into joint should be 10-11mm infront of anterior border of PCL
- Coronal plane
- tunnel trajectory 75degree from horizontal
- obtain by moving tibial starting point 1/2 between tibial tubercle and post medial edge of tibia
- tunnel trajectory 75degree from horizontal
- sagittal plane
-
Graft placement
- graft preconditioning- reduce stress relaxation by 50%
- graft tensioning at 20N/40N no clinical outcomes
Which graft is used in acl reconstruction?
-
Bone patellar bone autograft
- adv
- pt own bone
- most common source of graft
- faster incorporation
- less immune reaction
- long hx of use
- bone to bone healing
- ability to rigidly fix at joint line
- max load to failure =2600N (nor acl 1725N)
- dis
- highest incidence of ant knee pain 10-30%
- Patella fx
- Patella tendon rupture
- adv
-
Quadruple hamstring autograft
- adv
- smaller incision, less perio pain, less ant knee pain
- fixation strength <bone>
</bone><li>MAx load to failure =<strong> 4000N</strong>
</li>
- adv
</li>
<li>reduced peak flexion strength at 3 yrs cf BPB</li>
<li>concern about hamstring weakness in female athletes-> increase rerupture</li>
</bone>
* Allograft
* useful in revisions
* longer incoportion time
* risk of disease transmission
* ? re-rupture in atheletes
* Graft preparation
* Radiation- >3Mrads to kill HIV ( however this reduces the structural/mechanical properties of the graft
* Freezing: destroys cells but no effect on strength
Describe the rehab post acl reconstruction?
Early post-op
- immediate
- Ice
- Immediate WB- reduce patellofemoral pain
- Full passive extension
- Early rehab
- exercises thay don’t place excess stress on graft
- isometric hamstrng contractions at any angle
- isometric quads and hamstring contraction
- active knee motion 35-90 degrees flexion
- emhasized close chain( foot planted ) excerises
- svoid
- isokinetic quads strengthening
- open chain quads strenthening
What is the main complications of acl resconstruction?
-
Tunnel malposition
- most common cause of failure = 70%
-
Femoral tunnel
-
vertical femoral tunnel placement ( coronal plane)
- by starting tunnel at vertical position in notch = 12 o’clock lateral wall cf 9-10 o’clock
- will -> rotational instability, identified by a positive pivot shift
-
Anterior tunnel placement ( sagittal plane)
- -> knee that tight in flexion and loose in extension
- caused by failure to clear residents ridge
-
Posterior tunnel placement
- lax in flexion, tight in extension
-
vertical femoral tunnel placement ( coronal plane)
-
Tibial tunnel malposition
- __Anterior misplacement-> knee tight in flexion w impingment in extension
- Posterior misplacement -> acl impinges with PCL
Name the other causes of acl reconstruction complications?
- Indequate graft fixation
-
Tunnel osteolysis
- tx w observation
-
Missed diagnosis
- combined ACL, PLC injuries- failure to tx PLC_> failure of ACL
- Overaggressive rehab
-
Infection
- septic arthritis- satph aureus most common
- urgent joint aspiration+ gram stain & culture
- immediate athroscopic I&D
- Can often retain graft w mutliple I&D and Antibiotics for 6 wks minimum
-
Loss of motion and arthrofibrosis
- preop- ensure pt gained full rom be surgery
- proper tunnel placement criticial to full rom
- tx <12 wks aggressive Physio & serial splinting
- tx >12 wks lysis of adhesions/MUA
-
Infrapatella contracture syndrome
- increased knee stiffness post surgery
- Patella tendon rupture
- Patella fx
- complex Regional Pain Syndrome
- hardware failure
- Late arthritis
- local nerve irriatation- saphenous n
-
Cyclops lesion
- fibroproliferative tissue blocks extension
- click heard at terminal extension
What is epidemioogy and mechanism of PCL injuries?
- 5-20% of all knee ligamentous injuries
- mechanism
- direct blow to proximal tibia with a flexed knee ( dashboard injury)
- noncontact hyperflexion w plantar-flexed foot
- hyperextension injury
What is the mechanism of PCL?
- Primary restraint to posterior tibial translation
- functions to prevent hyperflexion/sliding
- isolated injuries cause the greatest instability at 90 degrees of flexion
Name associated injuries of PCL?
- PCL and posterior lateral corner
- Multiligamentous knee injury
- knee dislocation
What is the prognosis of a PCL def knee?
- PCL deficiency -> increased contact pressures in the Patellofemoral and Medial compartments of the knee due to varus alignment
- contraverisal whether late patellar and MFC chondrosis will develop
Describe the anatomy of the PCL?
- origin- Posterior tibial sulcus below the articular surface
- inserts anteriomedial femoral condyle
- broad, crescent shaped footprint
- PCL is 30% larger than ACL
- 2 bundles
-
anterolateral- tight in flexion
- most important for post stability at 90degrees of felxion
- ***NB PAL- PCL has AnteroLat bundle
- posteromedial- tight in extension
-
anterolateral- tight in flexion
-
Lies between 2 ligaments
- Ligament of Humphrey and ligament of wrisberg ( post)
- Middle Geniculate artery
Describe the classification of PCL injury?
- based on posterior subluxation of the tibia relative to femoral condyles ( w knee at 90 of flexion)
-
Grade 1- partial
- 1-5mm post tibial translation
-
Grade 2 complete isolated
- 6-10 mm post tibial translation
-
Grade 3
- >10mm post tibial translation
What is the presentation of a pt with PCL injury?
Symptoms
- Posterior knee pain
- instability
O/E
-
varus/valgus stress
- laxity at 0 degrees = MCL/LCL & PCL injury
- laxity at 30 degrees alone= MCL/LCL injury
-
Post sag sign- knees at 90 degrees
- medial tibial plateau rests 10mm ant to medial femoral condyle
- Post draw test- knee 90o post direct force applied and translation quantified- most accurate maneouver for dx PCL injury. abn >5mm translation
-
Dial test
- >10 degrees ER asymmetry at 30o and 90o = PCL and PLC injury
- >10 degrees ER asymmetry at 30 o only = PCL only
What is seen on imaging of PCL injury?
- AP and supine lateral
- Lateral stress view
- apply stress to ant tibia w knee flexed to 70o
- asymmetric post tibial displacement = PCL injury
- MRI
- cofirms dx
What is the tx of PCL injury?
Non operative
-
Protected WB & rehab
- for grade 1 / 2 injuries
- quads rehab w knee extensor strengthening
- return sport 2-4 wks
-
Relative immobilisation in extension 4 wks
- isolated grade 3 injuries
- young adults/ bony injury- surgery
- extension brace w limited daily rom
Operative
-
PCL repair of bony avulsion fx or PCL reconstruction
- for combined injuries PCL+ACL +PLC
- PCL grade 3 MCL/LCL, isolated grade 3 w bony avulsion, isolated PCL w unstable knee
- ORIF for bony avulsion
- Recon options
- Tibial inlay vs transtibial methods
- single bundle vs double bundle
- autograft vs allograft
- allograft used when mutilple lig to recon
- achilles, bone patella bone, hamstring, anterior tibialis
What is the outcomes of pcl repair for bony avulsion and reconstruction?
- Good results achieved w primary repair of bony avulsions
- primary repair of midsubstance rupture not successful
- Results of pcl recon ** less successful than ACL** and residual post laxity often exists
- successful reconstruction depends on addressing concomitiant ligament injuries
- no outcomes studies clearly support one recon technique over another
What is the tx of chronic PCL injuries?
-
High tibial osteotomy
- consider medial wedge osteotomy to treat both varus maliagnment and PCL deficiency
- Increasing the tibial slope helps reduce the posterior sag of the tibia
Describe the surgical techniques of PCL reconstruction?
-
Transtibial approach arthroscopic
- standards portals & accessory posteriomedial portal
- placed 1cm prox to joint line post to MCL
- avoid injury to branches of saphenous n
- postmedial corner of knee best visualises w 70o arthrocope thru notch or postermedial portal
- transtibial drilline anterior to posterior
- fix graft in flexion
- risk injury to popliteal vessels
- standards portals & accessory posteriomedial portal
-
Open ( tibial inlay)
- Posteromedial incision between medial head of gastronemius and semimebranosus
- used for ORIF bony avulsion
- screw fixation is within 20 mm of popliteal arrtery
-
Single bundle
- arthroscopic or open
- reconstruct anterolateral bundle
- tension at 90o flexion
-
Double Bundle
- Arthroscopic or open
- Anterolateral bundle tensioned at 90 o flexion
- postriomedial bundle tensioned in extension
Describe the rehab for PCL recon ?
- POst op care
- Immobilise in extension early and protect against gravity
- early motion is prone position
- Rehab
- Focus on quads rehab
- avoid resisted hamstring exercises ( hamstring curls)
- as hamstring create a aposterior pull on the tibia which increases stress on the graft