H.Mousavi Tadi,MDDepartment of orthopaedicEsfahan medical schoolFeb,2013

Anterior Cruciate Ligament Injuries

Anterior cruciate ligament (ACL) tearing

200,000 are torn each year, and 100,000 anterior cruciate ligament reconstructions are done each year in the United States.

Higher in people who participate in high-risk sports, such as basketball, football, skiing, and soccer.

50 percent of ACL injuries occur in combination with damage to the meniscus, articular cartilage, or other ligaments.

ANATOMY Surrounded by synovium,

extrasynovial ACL inserts on the tibial

plateau, medial to the insertion of the anterior horn of the lateral meniscus in a depressed area anterolateral to the anterior tibial spine.

The tibial attachment site is larger and more secure than the femoral site. The ligament is 31 to 35 mm in length and 31.3 mm2 in cross section.

Anatomy Anteromedial bundle

Smaller, tight in flexion Posterolateral bundle

Larger, tight in extension Both bundles parallel in

extension In flexion posterolateral

insertion moves forward Bundles cross in flexion Posterolateral bundle

loosens

BIOMECHANICS Of ACL Primary restraint to anterior tibial

displacement. AM band is tight in flexion. PL bulky portion of this ligament is

tight in extension. The PL bundle the principal

resistance for hyperextension. Tension is least at 30 to 40 degrees

of knee flexion. Secondary restraint on tibial

rotation and varus-valgus angulation at full extension.

Mechanism 70% non-contact mechanisms,

deceleration, jumping, cutting Twisting Hyperextension 30%direct contact A pop is frequently heard or

felt The patient usually has fallen

to the ground and is not immediately able to get up

Hemarthrosis : 70% acl tearing

PHYSICAL EXAMINATION of ACL

The Lachman test is the most sensitive test for anterior tibial displacement (95% sensitivity)

The pivot shift test requires a relaxed patient and an intact medial collateral ligament

Radiographic finding Segond fracture Avulsion fracture

MRI

Accuracy: 95% to 100%

Sagittal plan external rotation knee 15 degrees

Bone bruises: 80%

NATURAL HISTORY 50% -70% ACL injuries occur in combination with damage to

the meniscus, Osteochondral damage 21% to 31%.

Abnormal loading and shear stresses in ACL–deficient knee, the risk of late meniscal injury is high .

With chronic instability, up to 90% of patients will have meniscus damage 10 or more years after the initial injury.

Prevalence of articular cartilage lesions increases up to 70 % in patients who have a 10-year-old ACL deficiency.

ACL injury more common in female athlete:

Neuromuscular forces and control Landing biomechanics (conditioning and strength) play

biggest role females land in more extension, higher vaglus

moment Notch dimensions Ligament size Hormone levels Ligament laxity Valgus leg alignment Increased posterior tibial slope

Notch width index notch ratio was

0.231

Factors correlated with the need for surgery:

Younger, more active patients (reduces incidence of mensical or chondral injury)

Presence of associated ligamentous, chondral and meniscal conditions

Activity level/occupation Sports participation Older active patients (age >40 is not

contraindication if high demand athlete)

Surgical Procedure

Before any surgical treatment, the patient is usually sent to physical therapy.

Patients who have a stiff, swollen knee lacking full range of motion at the time of ACL surgery may have significant problems regaining motion after surgery.

It usually takes three or more weeks from the time of injury to achieve full range of motion. It is also recommended that some ligament injuries be braced and allowed to heal prior to ACL surgery

Graft Selection Autograft:

Bone-patellar tendon-bone

Quadrupled semitendinosus/ gracilis tendon

Bone quadriceps tendon

Allograft:

Achilles tendon Bone-patellar

tendon-bone Hamstring tendons Tibialis posterior

Ultimate tensile load

Bone–patellar tendon–bone graft

Recommended for high-demand athletes and patients whose jobs do not require a significant amount of kneeling.

most studies show equal or better outcomes in terms of postoperative tests for knee laxity

Postoperative pain behind the patella

Pain with kneeling Slightly increased risk

of postoperative stiffness

Low risk of patella fracture

Bone–patellar tendon–bone graft

Quadruple-stranded semitendinosus-gracilis tendon graft

ultimate tensile load reported to be as high as 4108 N.

Fewer problems with anterior knee pain or pain after surgery

Less postoperative stiffness problems

Smaller incision Faster recovery

Quadruple-stranded semitendinosus-gracilis tendon graft

Lack of bone to bone healing

Graft elongation (stretching)

Decreased hamstring strength

Quadriceps tendon autograft

Failed ACL reconstruction.

High association with postoperative anterior knee pain and a low risk of patella fracture

Graft OptionsBTB Hamstring Graft site morbidity Increased post op pain Pain with kneeling Scar length Quad weakness Osteoarthritis

More susceptible to graft elongation (stretching)

Allografts Advantages : No donor morbidity Decreased surgery time and

smaller incisions. Disadvantagrs: Risk of infection: Bacterial infection higher failure rate :23% to

34.4% in young, active patients returning to high-demand sporting activities.

Autograft failure rates ranging from 5% to 10%.

SYNTHETIC MATERIALS FORLIGAMENT RECONSTRUCTION

Gore-Tex Ligament :permanent load-bearing implant Stryker Dacron Ligament :function

as a permanent prosthesis Kennedy Ligament Augmentation

Device :function as a load-sharing implant to protect a biologic graft while it heals

No long-term studies of the artificial ligaments currently used support their routine use.

Use cautiously and to reserve them for salvage procedures when autogenous grafting and reconstructive procedures have failed.

Arch Orthop Trauma Surg. 2012 Sep;132(9):1287-97. doi: 10.1007/s00402-012-1532-5. Epub 2012 Jun 3

A systematic review of randomized controlled clinical trials comparing hamstring autografts versus bone-patellar tendon-bone autografts for the reconstruction of the anterior cruciate ligament.

CONCLUSIONS: ACL reconstruction with HT autografts or BPTB autografts achieved similar postoperative effects in terms of restoring knee joint function. HT autografts were inferior to BPTB autografts for restoring knee joint stability, but were associated with fewer postoperative complications.

Graft Placement.

Femoral site are more critical because of the proximity to the center of axis of knee motion

Femoral tunnel that is too anterior will result in lengthening of the intraarticular distance between tunnels with knee flexion. The practical implications of this anterior location are “capturing” of the knee and loss of flexion or stretching and perhaps clinical failure of the graft as flexion is achieved.

Isometric” femoral position limits changes in graft length and

tension during knee flexion and extension, which possibly may lead to overstretching or failure of the graft

normal anterior cruciate ligament is not isometric.bundles of the anterior cruciate ligament are under variable stress during knee motion.

The anteromedial bundle undergoes higher stress during flexion

posterolateral bundle undergoes higher stress during extension.

Tibial Tunnel Currently, most surgeons

advocate placement of the graft at the posterior portion of the ACL tibial insertion site near the posterolateral bundle position for best reproduction of the function of the intact ACL. This location also decreases graft impingement against the roof of the intercondylar notch with knee extension

Tibial Tunnel

< 70-75° from horizontal (in the coronal plane)

femoral tunnel Place the femoral

tunnel lower on the lateral wall toward the 10- or 2-o’clock position or even lower, which more accurately reproduces the femoral attachment site of the ACL and provides rotational stability

Single bundle versus double-bundle

Two bundles VS one Bundle

Disadvantage of 2 Bundles: Numbers of femoral tunnels Operative time Femoral condyle osteonecrosis,

chondrolysis More technically demanding Complicate revision procedure.

.Clin Orthop Relat Res. 2012 Mar;470(3):824-34. doi: 10.1007/s11999-011-1940-9

Single- versus double-bundle ACL reconstruction: is there any difference in stability and function at 3-year followup?

CONCLUSION: Double-bundle reconstruction of the ACL did not

improve function or stability compared with single-bundle reconstruction.

Arthroscopy. 2013 Feb;29(2):357-65. doi: 10.1016/j.arthro.2012.08.024.

Outcomes of Anterior Cruciate Ligament Reconstruction Using Single-Bundle Versus Double-Bundle Technique: Meta-analysis of 19 Randomized Controlle

CONCLUSIONS: Meta-analysis of random controlled trials revealed that

double-bundle anterior cruciate ligament reconstruction resulted in significantly better anterior and rotational stability and higher IKDC objective scores compared with single-bundle reconstruction. However, the meta-analysis did not detect any significant differences in subjective outcome measures between double-bundle and single-bundle reconstruction, as evidenced by the Lysholm score, Tegner activity scale, and IKDC subjective score.

Knee. 2013 Jan 7. pii: S0968-0160(12)00236-0. doi: 10.1016/j.knee.2012.12.004

Single-bundle or double-bundle for anterior cruciate ligament reconstruction: A meta-analysi

CONCLUSION: Our meta-analysis demonstrated the superiority of

double-bundle over single-bundle anterior cruciate ligament reconstruction. The double-bundle ACL reconstruction technique has better outcomes in rotational laxity (pivot-shift test, KT grading and IKDC grading). However, for functional recovery, there was no significant difference between single-bundle and double-bundle reconstruction technique

RESULTS OF ACL RECONSTRUCTION

Goals: Restore normal joint motion Return full function Prevent secondary injury Prevent joint arthrosis

Am J Sports Med. 2010 Nov;38(11):2201-10. doi: 10.1177/0363546510373876. Epub 2010 Aug 16

Knee function and prevalence of knee osteoarthritis after anterior cruciate ligament reconstruction: a prospective study with 10 to 15 years of follow-up.

CONCLUSION: An overall improvement in knee function outcomes was

detected from 6 months to 10 to 15 years after ACL reconstruction for both those with isolated and combined ACL injury, but significantly higher prevalence of radiographic knee osteoarthritis was found for those with combined injuries.