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Toronto Notes 2019 Knee Quadriceps/Patellar Tendon Rupture
Mechanism
• suddenforcefulcontractionofquadricepsduringanattempttostop
• morecommoninobesepatientsandthosewithpre-existingdegenerativechangesintendon
■ DM, SLE, RA, steroid use, renal failure on dialysis
Clinical Features
• inabilitytoextendkneeorweight-bear
• possibleaudible“pop”
• patellainlowerorhigherpositionwithpalpablegapaboveorbelowpatella,respectively • mayhaveaneffusion
Investigations
• askpatienttostraightlegraise(unablewithcompleterupture)
• kneeX-raytoruleoutpatellarfracture,MRItodistinguishbetweencompleteandpartialtears
• lateralview:patellaaltawithpatellatendonrupture,patellabaja(infera)withquadricepstendon
rupture
Treatment
• non-operative
■ indication: incomplete tears with preserved extension of knee ■ immobilizationinbrace
• operative
■ indication: complete ruptures with loss of extensor mechanism
• earlysurgicalrepair:betteroutcomescomparedwithdelayedrepair(>6wkpost-injury) • delayedrepaircomplicatedbyquadricepscontracture,patellamigration,andadhesions
Dislocated Knee
Mechanism
• highenergytrauma
• bydefinition,causedbytearsofmultipleligaments
Clinical Features
• classifiedbyrelationoftibiawithrespecttofemur ■ anterior, posterior, lateral, medial, rotary
• kneeinstability
• effusion
• pain
• ischemiclimb
• Schenckclassification
Investigations
• X-ray: AP, lateral, skyline
• associatedradiographicfindingsincludetibialplateaufracturedislocations,proximalfibularfractures,
and avulsion of fibular head
• ABI(abnormalif<0.9)
• arteriogramorCTangiogramifabnormalvascularexam(suchasabnormalpedalpulses)
• assessmentofperonealnerve,tibialartery,andligamentousinjuries
Treatment
• urgentclosedreduction
■ complicated by interposed soft tissue
• assessmentofperonealnerve,tibialartery,andligamentousinjuries
• emergentoperativerepairifvascularinjury,openfractureordislocation,non-reducibledislocation,
compartment syndrome
• kneeimmobilizationx6-8wk
Specific Complications
• highincidenceofassociatedinjuries • poplitealarterytear
• peronealnerveinjury
• capsulartear
• chronic:instability,stiffness,post-traumaticarthritis
Orthopedics OR35
Patellaalta=highridingpatella Patellabaja(infera)=lowridingpatella
Schenck Classification
Type 1: Single ligament injury (ACL or PCL) Type 2: Injury to ACL and PCL
Type 3: Injury to ACL, PCL
and either MCL or LCL
Type 4: Injury to ACL, PCL, MCL, LCL Type 5: Multiligamentous injury
with periarticular fracture