Diagnosis and Treatment of ACL Injuries

Jeff Martin DO

Author has no conflicts of interest to disclose

Improve knowledge and treatment of ACL tears from injury through treatment and rehabilitation.

Goals:

Introduction

• 150,000-400,000 ACL tears annually• Chronic ACL deficient knees associated with – chondral injuries– complex unrepairable meniscal tears– relation with arthritis is controversial

• 2nd most commonly tested topic on yearly Orthopedic resident inservice test over the last ten years

The Female Athlete • Women athletes have 4-6x rate of ACL injuries

then males– Increased Q angle – Valgus Leg alignment– Effects of estrogen– Small ACL width– Narrow femoral notch– Increased Joint Laxity – Jump patterns (extended knee with greater hip

adduction moments)• Focus of ACL injury prevention programs which have shown

decreased incidence of ACL tears

Prevention

Level 2 evidence shows that high intensity plyometrics coupled with balance training and strengthening improves neuromuscular feedbackThis reduces ligamentous strain during pivoting

and landing activitiesFor the training regimen to be effective, a

minimum of 1 session per week for 6 weeks needs to be implemented

• neuromuscular training / plyometrics (jump training)

• land from jumping in less valgus and more knee flexion

• increasing hamstring strength to decrease quadriceps dominance ratio

Anatomy

• Primary function is to prevent anterior translation of the tibia

• Secondary role in preventing internal rotation of tibia

Anatomy of ACL ACL attachments:

Arises from posteromedial corner of the lateral femoral condyle in the intercondylar notch

Broad insertion at anterior intercondylar portion of the tibia

length of 38 mm (range 25 to 41 mm) width of 10 mm (range 7 to 12 mm)

ACL is intra-articular and extra-synovial

Blood supply is the middle genicular artery Due to relatively poor blood supply, ACL has little

intrinsic capacity to heal

ACL composed of Two Bundles

Anteromedial • Tight in Flexion 45-60• Controls anterior

Translation

Posterolateral • Tight in Extension • Rotator Stability and

anterior motion

Mechanism of Injury

• typically, the ACL is torn in a noncontact deceleration situation that produces a valgus twisting injury

• this usually occurs when the athlete lands on the leg and quickly pivots in the opposite direction

• Other Mechanisms - hyperextension- marked internal rotation of tibia on femur- pure deceleration

Presentation

• Classic “pop”• 70 - 80% of acute hemarthroses are secondary

to ACL injury

Physical Exam ACL• Quadriceps avoidance gait– most patients will alter their gait in

order to avoid anterior displacement of the tibia which occurs with quadriceps contraction• between 0 to 45 deg of flexion,

contraction of the quadriceps will cause anterior translation of the tibia (which is normally resisted by the ACL)

• Lachman (most sensitive)• Anterior drawer• pivot shift (most specific, usually

done under anesthesia)

• Classic O’Donoghue Triad (Terrible Triad) rare – ACL, MCL, medial meniscus

• Lateral meniscus– Acute

• Medial meniscus– Chronic

• At the time of injury approximately 1/3 of patients will have meniscal tears

Imaging ACL Tear• Plain radiograph– Segond (capsular sign)• Small fracture at periphery of proximal lateral tibia

Imaging• MRI• ACL Tear best seen on sagittal view• Osteochondral contusion @ middle third of the lateral femoral

condyle and posterior third of the lateral tibial plateau• 50% injuries

Treatment• Nonoperative– low demand patients with decreased laxity– increased meniscal/cartilage damage linked to• loss of meniscal integrity• frequency of buckling episodes• High level of activity (e.g. jumping, cutting, side-to-side

sports, heavy manual labor)

Operative (ACL reconstruction)

• Indications• in younger, more active patients (reduces

incidence of mensical or chondral injury)• older active patients (Age >40 is not

contraindication if high demand athlete)• ACL reconstruction failure• Attempted ligament "repair" has high failure

rate

Surgical Techniques

• 2006 study with BTB (minimum 13 year follow up) showed 79% of patients had radiographic evidence of degenerative changes

• 2007 meta-analysis reported only 33-41% normal knee scores after ACL reconstructions

Tunnel Placement • Transtibial Technique has tendency to place femoral tunnel

vertical=less rotational stability• Anatomic ACL reconstructions- place tunnnels in native

femoral and tibial attachment sites

Double Bundle vs Single Bundle

• Some biomechanical evidence suggests that double bundle reconstructions result in better restoration of knee stability

• No clinical evidence of difference

Surgery

• Arthroscopic Assisted ACL Reconstruction with Patellar tendon Autograft– 1) If certain ACL is nonfunctional (side to side

difference of >5mm), harvest autograft before the arthroscopy. If not certain, evaluate the knee arthroscopically first.

Surgery

• 2) The middle third (~10mm) of the patellar tendon is harvested with bone plugs from the tibia and patella. Bone plugs are trimmed to facilitate passage through the osseus tunnel. Holes are drilled in the bone plugs to pass nylon sutures. Arthroscopy.

Surgery

• 3) Arthroscopic Soft tissue debridement of ACL attachment sites

• 4) Position and prepare osseus tunnels– Length of tibial tunnel is calculated– Cannulated core drill used to create

a tibial tunnel and then a femoral tunnel for transtibial technique

– Accessory medial portal can do tibial or femoral tunnel first.

• 5) Graft implantation and fixation– Pin is retrograded through

tunnels and out anterolateral thigh

– suture on graft is threaded through the pin and the suture and graft are pulled through tunnel into the joint

– Bone plugs are fixed by interference screws and inserted flush with the bone tendon junction

Surgery

• 6) Knee flexed through full ROM, pivot and lachman tests performed– Core of bone from the tibial tunnel used to fill bony defect

of the patella– Patellar tendon loosely re-approximated to prevent any

palpable gaps w/out shortening the patella tendon– Peritenon, subcutaneous tissue, skin closed in separate

layer

Graft Options in ACL Reconstruction

Autograft

Bone-patella tendon-boneHamstringQuadriceps

AllograftBone-patella tendon-boneHamstring Quadriceps Tibialis anterior Tibialis posterior Achilles tendonFascia lata Peroneus longus

ACL AutograftsAdvantages:

No issue regarding cost and availability of graft

No risk of disease transmission

Good potential of bone-graft interface

No tissue rejection

DisadvantagesMore wound painMore prominent scarLonger surgical timeDonor site morbidity

ACL AutoGrafts Load to Failure

• Native ACL 2160N• 10mm BTB 2977N• Quadrupled Hamstring

4090N• Quadriceps 2352 N

1 N = 1 kg m/s2⋅

Bone-patella tendon-bone

For past few decades, Gold Standard for ACL Reconstruction

Clinical Studies have not shown significant differences between grafts Ease of harvestBone-to-bone healing

with secure fixation

Bone-patella tendon-bone

DisadvantagesPotential negative effect on

the knee extensor mechanism

Anterior knee pain / kneeling pain

Risk for patella fractureAnterior knee numbness

Hamstring tendonCombined semitendinosus

and gracilis hamstring tendons

Less anterior knee pain, no disruption of knee extensor mechanism, and less risk for patella fracture

Quadrupled Hamstring strongest Graft 4090N nearly double native ACL

Hamstring tendon

• Potential Limitations:• Slower soft-tissue graft-tunnel healing (when

compared to bone-to-bone healing with patella tendon grafts)

• Potential for tunnel widening and graft laxity • Functional hamstring weakness from graft

harvesting• Some studies show lower return to pre-injury

activity levels

Quadriceps tendonNoted to be more

difficult to harvestPotential for anterior

knee painPersistent quadriceps

weakness?Thicker then patellar

tendon

Graft Selection in Anterior Cruciate Ligament Reconstruction Walter R. Shelton, MD Bryan C. Fagan, MD JAAOS 2011;19: 259-264

AllograftsWide range of graft sources and availabilityAvailability of larger graftsQuicker surgical timeNo donor site morbidityLower incidence of post-operative arthrofibrosisFaster immediate post-operative recovery and less post-

operative painEasier rehabilitationUseful in revision ACL reconstruction procedures

ACL Allografts

DisadvantagesExpensive ($1500)Risk (minimal) of tissue rejectionRisk (minimal) of disease transmissionRelatively longer healing time of the graftVariability in mechanical properties of ACL allograftsIn some studies higher failure rates

When irradiated and chemically processed grafts were excluded, then failure rates were no longer statistically significant

Gamma Irradiation of ACL Allografts One of the most widely utilized forms of secondary graft sterilization is

gamma irradiation Known pathogens include HIV, hepatitis, bacteria, and fungus

Susceptibilities: Non-spore-forming bacteria: 0.5 Mrad Bacterial spores: 2.1 Mrad Yeast/Mold: 0.8 Mrad HIV: 1.5 – 4 Mrad

Irradiation doses > 2 Mrad have demonstrated decreases in biomechanical properties of the allograft Increased elongation and decreased stiffness, maximum force, strain, and maximum

stress Disruption of collagen organization and cleaving of polypeptide bonds

Studies have shown that lower irradiation levels (1.0 – 2.0 Mrad) do not compromise graft biomechanical properties These doses will not eliminate HIV, hepatitis, and spore-forming bacteria.

Demonstrates the importance of adequate screening

ACL Tears in Children• Treatment in Children (< 14 yrs with open physis)– strongly consider operative• activity limitation impractical• transphyseal soft tissue grafts rarely lead to growth

disturbances• avoid transphyseal metallic fixation• Fixation outside the physis (over the top techniques)

RehabROM

Immediate ROM is more beneficial to a healing graft than delayed motion

Immediate ROM and CPM have not been shown to endanger ACL grafts

ROM helps prevent scar tissue formation in the intercondylar notch and elsewhere

Knee extension loss is one of the more common complications after ACL reconImmediate, full, passive, terminal extension is required

RehabWeight Bearing

At least partial weight bearing should begin initially to ensure that proper gait sequence and cadence can be performedImmediate weight bearing has been shown to decrease

incidence of anterior knee painPain should be controlled to allow progression to full

weight bearing (avoids quadriceps avoidance gait)Some protocols limit weight bearing after soft-tissue

fixation methods

– early rehab • focus rehab on exercises that do not place excess stress on

graft – appropriate rehab

» isometric hamstring contractions at any angle» isometric quadriceps, or simultaneous quadriceps and

hamstrings contraction» active knee motion between 35 degrees and 90 degrees of

flexion» emphasize closed chain (foot planted) exercises

– avoid » isokinetic quadricep strengthening (15-30°) during early rehab » open chain quadriceps strengthening

OutcomesAn evaluation of NFL wide receivers and running

backs after ACL reconstruction showed only 80% of the athletes returned to playOf those returning, there was a 30% decrease in

statistical performanceRevision reconstructions result in 60% return to

athletic activity, but with decrease level of performanceMost common reason for ACL recon failure?

Technical failure (tunnel placement)Single stage vs two stage revisions are dictated by

tunnel quality and degree of osteolysis

Complications

• Infection – septic arthritis

• Staph aureus most common

– treatment • immediate arthroscopic I&D• often can retain graft with multiple I&Ds and abx (6 weeks minimum)

• Loss of motion & arthrofibrosis – preoperative prevention

• be sure patient has regained full ROM and swelling gone before you operate

– operative prevention • proper tunnel placement is critical to have full range of motion

– postop prevention • aggressive cryotherapy (ice)

• Infrapatellar contracture syndrome• Patella Tendon Rupture• RSD (complex regional pain syndrome)• Patella fracture• Hardware failure• Tunnel osteolysis• Late arthritis

– Thought to be related to meniscal integrity • Local nerve irritation

– saphenous nerve • Cyclops lesion

– fibroproliferative tissue blocks extension– "click" heard at terminal extension

Thank You

References• Graft Selection in Anterior Cruciate Ligament Reconstruction Walter R.

Shelton, MD Bryan C. Fagan, MD J Am Acad Orthop Surg 2011;19: 259-264Copyright 2011 by the American Academy of Orthopaedic Surgeons.BiomechanicsMay 2011, Vol 19, No 5259Review Article

• Does ACL Reconstruction Alter Natural History? A Systematic Literature Review of Long-Term Outcomes Chalmers P et al. J Bone Joint Surg Am, 2014 Feb 19;96(4):292-300.

• MR Imaging of Complications of Anterior Cruciate Ligament Graft Reconstruction. Bencardino J et al. Radiographics, 2009 Nov Vol 29 2115-2127

• Nonsurgical or Surgical Treatment of ACL Injuries: Knee Function, Sports Participation, and Knee Reinjury The Delaware-Oslo ACL Cohort Study. Grindem H et al. Bone Joint Surg Am, 2014 Aug 06;96(15):1233-1241.

• Comparison of Functional Outcome Measures After ACL Reconstruction in Competitive Soccer Players, A Randomized Trial. Mohammadi F et al. Bone Joint Surg Am, 2013 Jul 17;95(14):1271-1277.

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