Anterior Cruciate Ligament (ACL) Reconstruction

Original Editors - Dorien Scheirs

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Definition/Description

The Anterior Cruciate ligament injury ( ) means that there is a joint instability of the knee that leads to decrease of activity. It is caused by a twist of the knee.

The reconstruction of the anterior cruciate ligament is one of the most common orthopedic surgery, at commonly there is a articular cartilage degeneration.

Clinically Relevant Anatomy

The anatomy of the femoral and the tibial tunnel:

Femoral tunnel:

The tunnel at the sagittal side of the knee goes to the cortex of the femur and the roof of the intercondylar notch.
Tibial Tunnel:

First the tibial tunnel has to be created at the correct way, to prevent impingement of the grafts against the roof of the intercondylar notch. The tibial tunnel should be oriented at the Blumensaat line. This line goes from the tibial tuberosity and the posterior side should be oriented to the line of Blumensaat

Which Graft?

Anterior cruciate ligament (ACL) reconstruction can be done with several different graft choices. These include patellar tendon, hamstring tendon, and donor tissue (allograft). Each of these choices has advantages and disadvantages.

Patellar Tendon

When a patellar tendon graft is taken, the central 1/3 of the patellar tendon is removed (about 9 or 10 mm) along with a block of bone at the sites of attachment on the kneecap and tibia.

Advantages:

• Closely resembles what needs reconstruction.  The length of the patellar tendon is about the same as the ACL, and the bone ends of the graft can be placed in to the bone where the ACL attaches.
• Early bone to bone healing at 6 weeks.  Bone to bone healing is considered to be stronger than soft tissue to bone healing as with a hamstring graft.

Disadvantages:

• Harvest site morbidity of Patellar_Tendinitis and anterior knee pain.
• Patellofemoral joint tightness with late chondromalacia.
• Late patella fracture
• Late patellar tendon rupture
• Loss of range of motion
• Injury to the infra-patellar branch of the saphenous nerve.
  

Hamstring Tendon

With the improvement in the technique of the preparation of the multiple bundle graft, this graft choice has become more popular.  

Advantages:

• 4 bundle graft is stronger and stiffer than the patellar tendon.
• No risk on anterior knee pain as with the patellar tendon.
• Smaller incision.
• Pain in the immediate post-operative period is less.

Disadvantages:

• Graft harvest can be difficult expecially in those with small muscles.
• Graft fixation to bone requires additional 'hardware' i.e. screws, endobutton.

• Graft healing of soft tissue to bone takes longer to heal, 10-12 weeks.  
• Donor site morbidity.

Allograft (Donor Tissue)

Allograft is most commonly used in lower demand patients, or patients who are undergoing revision ACL surgery. Biomechanical studies show that allograft (donor tissue from a cadaver) is not as strong as a patient's own tissue (autograft). For many patients, however, the strength of the reconstructed ACL using an allograft is sufficient for their demands. Therefore this may be an excellent option for patients not planning to participate in high-demand sports (e.g. soccer, basketball, etc.).

Advantages:

Decreased operative time

• No need to remove other tissue to use for the graft
• Smaller incisions
• Less post-operative pain. 

Disadvantages:

• Risk of disease transmission.
• Graft preparation to kill the living cells decreases the strength of the tissue.
• Longer graft to bone incorporation time.
• Not readily available
• Expensive

Summary

Many surgeons have a preferred technique for different reasons. The strength of patellar tendon and hamstring grafts is essentially equal. There is no right answer as to which is best, at least not one that has been proven in orthopedic studies. The strength of allograft tissue is less than the other grafts, but the strength of both the patellar tendon and hamstring tendon grafts exceed the strength of a normal ACL.

Successful anterior cruciate ligament reconstruction is dependent on a number of factors including: patient selection, surgical technique, postoperative rehabilitation, and associated secondary restraint ligamentous instability. Errors in graft selection, tunnel placement, tensioning, or fixation methods chosen may also lead to graft failure. The comparison studies in the literature show that the outcome is almost the same irregardless of the graft choice. The most important aspect of the operation is to place the tunnels in the correct position. The choice of graft is really incidental.

Outcome Measures

The surgery of the ACL has a good to excellent outcome. Only 15 % remains elusive. Although some patient have artistic changes. Even if the ligament is reconstructed

Examination

The reconstruction of the anterior cruciate ligament is one of the most common orthopedic surgery, at commonly there is a articular cartilage degeneration.

A total collateral ligament rupture and a full-thickness cartilage lesion would be visualized by an MRI.
                 - There is a patella tendon procedure: involves the central third of the ipsilateral patellar tendon. There is a                          fixation of the bone blocks within the tibia and femur
                - There is a hamstring-tendon procedure: four-layer, fold-up M. gracilis en M. semitendinosus tendons.

                  This means that the take a part of the patella tendon or M. gracilis or M. semitendinosus for the                                       reconstruction of the anterior cruciate ligament. The surgery takes places at 10 weeks after the injury.

The reconstruction of the Anterior Cruciate ligament is compared with other treatments. A central aspect of the treatment is a physical therapist. But it’s not always offered.

Double-bundle reconstruction:
The semitendinosus is used with the autograft trough 2 tunnels in both tibia and femur. The autograft method: bone-to-bone ( BTB) and hamstrings/ semitendinosus grafts. They also can use 3 tunnels: 2 tunnels through the tibia and 1 tunnel through the femur.

There are 2 important procedures for the reconstruction.

The first procedure is the autologous bone-patella tendon-bone graft and the autologous four-strand hamstrings graft. These are the 2 most popular procedures.

By the bone-patella tendon-bone graft, they take a couple of bone blocks from the patella and the tibial tubercle. This procedure causes more anterior knee pain than the semitendinosus graft. By the second procedure, they take the distal end of the semitendinosus and the gracilis tendon.

Other procedures are: the LARS artificial ligament,( Ligament Advanced Reinforcement System )iliotibial tract allografts, cadaveric allografts, synthetic materials and grafts from living related donor people. But all materials have their drawbacks: cross-infections, breakage, immunological responses, chronic effusions, recurrent instability, …¹

Autograft vs allograft reconstruction of the anterior cruciate ligament

Autograft: patellar tendon grafts and Achilles tendon grafts. Standard anterolateral and anteromedial portals were created. A 3-4 cm incision was made into the tibial tunnel over the proximal part of the tibia. Then the ACL beath pin was drilled into the cortex of the femur and proximally out of the skin. At last the ACL reamer is placed over the pin trough the tibial tunnel.
The allograft method: When they used this method, they’ve taken materials from cadavers. But this method isn’t that reliable as the autograft method. And it needs a longer time to revascularize.

Postoperative treatment and rehabilitation : ²

Anti-inflammatory medication, a treatment for the swelling for 5 days after the surgery. After 3 days the patient can do straight leg raising exercises for about 200 times a day. This is necessary for strengthen the Quadriceps and to prevent other muscles to shorten.
              - After 2 – 3 weeks: active flexion and extension and plantair flexion
              - After 4 weeks: exercises for proprioception
              - After 2 -3 months: exercises for proprioception and anti-resistance training.

KINEMATICS ³

The kinematics of the single- bundle ACL reconstruction: the kinematics showed that the standard single-bundle ACL reconstruction doesn’t create the same kinematics as the intact ACL in normal activities. Only the anteroposterior stability seems to be reconstructed . When the knee turns, there is an abnormal tibial rotation in the knee. So the single-bundle ACl reconstruction does not recreate a normal rotation in the knee.

The kinematics of the double-bundle ACL recontstruction: the kinematics of the double-bundle ACL reconstruction are better than the kinematics of the single-bundle ACL reconstruction. The anterior translation is comparable with the intact ACL at 0° flexion. But the most stable position of the knee is 15° and 75°.

Medical Management

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Physical Therapy Management

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Key Research

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Resources

1) R. B. FROBELL, Ph. D. E.V. ROOS, … “A randomized trial of treatment for acute anterior cruciate ligament tears” , The new England journal of medicine, july 2010 http://www.nejm.org/doi/full/10.1056/NEJMoa0907797#t=article

2) D.L SHI, “Effect of anterior cruciate ligament reconstruction on biomechanical features of knee in level walking: a meta-analysis” , Chinese medical journal,2010
http://www.cmj.org/Periodical/paperlist.asp?id=LW2010113338438408321&linkintype=pubmed

3) A.B. MEYERS, A.H. HAIMS, ‘Imaging of anterior cruciate ligament repair and its complications’, American Journal of roentgen logy. Febuary 2010 http://www.ajronline.org/cgi/reprint/194/2/476 

4) C. LEGNANI, A. VENTURA, ‘Anterior cruciate ligament reconstruction with synthetic grats. A review of literature’, January 2010, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2903133/?tool=pubmed

5) J.M. HUAN, ‘Cruciate ligament reconstruction using LARS artificial ligament under arthroscopy: 81 cases report’, Chinese medical journal, 2010 http://www.cmj.org/Periodical/paperlist.asp?id=LW2010120595905909751&linkintype=pubmed

6) E. TSUDA , I. YASUYUKI, “Comparable results between lateralized single- and double- bundle ACL reconstructions”, Hirosaki university graduate school of medicine, october 2008http://www.cmj.org/Periodical/paperlist.asp?id=LW2010120595905909751&linkintype=pubmed

7) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2650066/?tool=pubmed  level of evidence is II, therapeutic study

Clinical Bottom Line

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Recent Related Research (from Pubmed)

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References

^{1 C. LEGNANI, A. VENTURA, ‘Anterior cruciate ligament reconstruction with synthetic grats. A review of literature’, Januari 2010}

^{2 J.M. HUAN, ‘Cruciate ligament reconstruction using LARS artificial ligament under arthroscopy: 81 cases report’, Chinese medical journal, 2010}

^{3 A.B. MEYERS, A.H. HAIMS, ‘Imaging of anterior cruciate ligament repair and its complications’, American Jrounal of roentgenology. Febuari 2010}