Reconstruction of the Reconstruction of the Ligaments of the KneeLigaments of the Knee

ContentsContentsACL reconstruction

EvaluationSelectionEvolutionGraft issuesNotchplastyTunnel issues

MCL PCLPosterolateral ligament complexCombined injuries

Evaluation & ImagingEvaluation & ImagingClinical examRoutine xrays: AP/lateral (avulsion fxs)Special xrays: sunrise/tunnel; Rosenberg viewMRI: 90% sensitive (acute ACL)

Not good for partial tears (<50%)Identify associated injuriesSensitive for PCL except chronic tears

Who is a candidate for Who is a candidate for ACL reconstruction?ACL reconstruction?

Young; athleteSymptoms of instability & painRisk of further meniscal & articularcartilage injuryPresence of degenerative changes

NonsurgicalNonsurgical treatment treatment for ACL deficiencyfor ACL deficiency

Sedentary patients; knees with advanced degenerative changesFunctional bracingRehab: full ROM, closed kinetic chain strengthening, focus on hamstrings (quads & gastroc), proprioceptive re-edBehavior modification

Evolution of ACL surgeryEvolution of ACL surgeryDirect repairExtraarticular (nonanatomic) reconstrucProsthetic replacement (40-80% failure)Repair with LAD (no better than repair)Arthroscopically assisted reconstruction

AutograftAllograft

Graft choicesGraft choicesAutografts

Bone-patellar tendon-boneQuadrupled hamstrings (Grac & Semi-T)Quadriceps tendon

AllograftsBone-patellar tendon-boneAchilles’ tendonHamstringsQuadriceps tendonFascia lata

AutograftAutograft vs. Allograftvs. AllograftViral disease transmission (1:1million)

Deep freezing leaves some cells (10%)Freeze-drying & cryo weaken graft; limited self-life

Graft incorporation & remodeling is faster with autografts. (graft is weakest @ 8-12wks)Donor site morbidity with autografts?more creep with allografts

Graft selectionGraft selectionGraft strength: patellar tendon (150% of ACL); 4-HT (150-200%); auto>allo,earlyBone/bone vs. tendon/bone fixation & healingHamstrings > tunnel wideningHamstring weakness- clinically not a problemPatellar tendon > anterior knee pain (10-40%); fracture risk (2%); 10% decrease in quad strength is usual

Graft Pros & ConsGraft Pros & Cons

The The notchplastynotchplastyImproves visualization of femoral tunnel & creates clearance for the graftCurrent trend is to minimize the plastyMinimizing decreases postop pain, swelling, bleeding, & potential regrowth.Too much may lateralize the femoral insertion & lead to abnormal kinematics.A recent study > histopathologic changes in cartilage @ 6mo c/w early DJD100 pts > no short-term benefit w/ plasty

Tunnel placementTunnel placementTibial tunnel @ postero-

medial footprint.Femoral tunnel @ 10-11

or 1-2 o’clock.Leave 1-2mm ofposterior wall.

Tunnel misplacementTunnel misplacementTibial tunnel

Anterior (most common)> graft impingement, loss of extensionPosterior > continued pathokinematics

Femoral tunnelAnterior (most common)> high strains in flexion, loss of flexion, inc graft stretchingPosterior (over-the-top)> blow-out, tight in extension, inc AP laxity in flexion

Tunnel techniqueTunnel techniqueTibial tunnel @ 45-55degree

angle toward footprint;longer grafts (b-pt-b) may need higher angles.

Femoral tunnel drilled w/ 100-120degrees of knee flexion to avoid blow-out.

Intraop lateral xray

The graft: The graft: intraopintraop pointspointsPreconditioning (tensioning): 20-80N

Decreases up to 30% soon after fixationExcessive > restrict motion; accel arthrosisInadequate > continued instability

FixationType > interference screws (tit/bio), endo, transfixTechnique > at joint line; avoid divergence (>15*)

Rotating graft by 90deg or more increases strength by approx. 20%

Graft fixationGraft fixationSingle-incision Double-incision

Blunt-threaded bioabsorbable screws allow fixationat the joint line on both sides.

Fixing the graftFixing the graftSnug fit b/w graft and tunnel

Underdrill & dilate-up7mm & 9mm screws

Avoid screw divergencePlace femoral screw @ 100-120deg flexionPlace femoral screw through tibial tunnel

? of knee positionSlight flexion > least AP laxity, tightest LachmanFull extension > limits risk of flexion contracture

Results of ACL recon.Results of ACL recon.Most series show 88-95% good to excellent results @ 3-5yr f/u.Objectively stable knees

Instrumented laxity less than 3mmPivot shift less than 1+

Subjective success in 80-92% @ 3-5yrsFull return to preinjury activity levels w/o significant symptoms

Meniscal resection & cartilage damage adversely effect results.Better rates of meniscal healing w/ ACL surg.

Medial Collateral Medial Collateral LigLig..Grades: medial opening in 30deg flex

1 = 1-5mm2 = 6-10mm3 = 11-15mm

Nonsugical rx is the mainstayBracing & crutches (b/w 2-6wks)Rehab: early quad & hamstring strength

Combined injuries (post capsule,cruciate)Nonsurg & surgical rx have been recommendedHigher risk of stiffness w/ proximal injuries

Posterior Posterior CruciateCruciate LigLig..Pt c/o pain rather than instability.Chronic (10-20yr) PCL deficiency

Medial & PF compartment arthrosisCadaver study > inc contact pressures

Nonsurg rx focuses on quad strength? true isolated injuries

Usually partial tears (do well)Serial bone scans > early cartilage damage? missed combined injuries (60% have posterolatcomplex)

Surgery for PCLSurgery for PCLRecommended w/in first 2 weeksExam > 3+ posterior drawer, increased ER @ 30 & 90deg flexion20% of athletes go on to reconstruction2 distinct bundles > not isometricGrafts

Achilles tendon allograftPatellar & quad tendon autografts

Increasing interest in a 2-bundle techniquePostop rehab: much less aggressive than ACL rehab.

Tunnel placement: PCLTunnel placement: PCLAnterolateral bundle

is the focus ofreconstruction.

•Larger & stronger•Taut in flexion

PosterolateralPosterolateral ComplexComplexIT band, biceps femoris, LCL, fabello-fibular lig, arcuate lig, popliteus tendon, & posterolateral capsuleSpectrum of injury; assoc w/ PCL & bicruciateinjuryc/o instability, esp. descending stairs>10% incidence of peroneal nerve injuryIncreased lateral comp translation & medial comp compression (inc adduction moment in varus knees)

PosterolateralPosterolateral complex complex surgerysurgery

Direct primary repair for acute injuriesavulsion fxs, ie. fibulaw/in first few weeks; lateral approachaddress all injured structures

Reconstruction for chronic injuriesTraditional procedures (mixed results)

Biceps tenodesis (Clancy), arcuate lig advancementAnatomic procedures (results pending)

Popliteal lig. & LCL reconstruction (auto & allograft sling)HTO before reconstruction in pts w/ varusthrust

Results of PL complex Results of PL complex repair/reconstructionrepair/reconstruction

Few reports or seriesFanelli et.al. (recent retrospective study)

64% restoration of PL stability w/ arcuatecomplex bony recession78% success rate w/ Achilles tendon allograft loop reconstruction of the LCL

Combined injuriesCombined injuriesMCL & ACL

Reconstruct ACL; brace for MCLMay need early MCL repair for grade 3 injuries w/ opening in full extension.

Increased risk of postop stiffness

MCL & PCLGrossly unstable kneesEarly MCL repair w/ PCL reconstructionMay consider bracing x4-6wks, then PCL recon.

Tibia must remain reduced in the brace.