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Anterior Cruciate Ligament (ACL) Reconstruction

Anterior Cruciate Ligament (ACL) Reconstruction


The anterior cruciate ligament (ACL) is important for maintaining the stability of the knee joint, especially during activities that involve braided rotations or kicks. A ruptured ACL can make the knee unstable, and the joint may become more damaged over time. ACL reconstruction is surgery Choose to restore knee stability.

Non-surgical treatment is preferred when a patient has:

  • Is older than 35 years old
  • No or slight anterior tibial subluxation
  • Has no additional intra-articular injury
  • Is not highly active

Surgical treatment is preferred when a patient has:

  • Is younger than 25 years old
  • Has a marked anterior tibial subluxation
  • Has additional intra-articular damage
  • Is highly active

Most patients fall between these two sets of criteria, so treatment should always be assessed on an individual basis.

General principles of ACL reconstruction


  • Restore stability
  • Maintain full active range of motion
  • Isometric ligament function

The goal of reconstructive surgery is to restore stability and maintain full active ROM. A normal ACL provides functional stability against both anteroposterior translation and rotational subluxation.

Reconstruction techniques vary depending on the available graft material. Options for surgical treatment may vary depending on the patient’s symptoms and their level and type of activity. That is, if their motion involves rotational motion. Conservative management is an option, but in the long run The prognosis is poor [2].

There is no gold standard for ACL reconstruction. Every surgeon has different techniques and preferences. Results shown by recent techniques are still inconclusive about long-term outcomes [3]. Different techniques including arthroscopic and open surgery intra- and extra-articular Reconstruction of the femoral tunnel placing the number of grafts in single-bundle versus double-bundle and fixation methods. [3] Extra-articular reconstruction has been used to address critical displacement and has been shown to be more effective than that provided by intra-articular reconstruction, but lacks the residual stability. Intra-articular became the preferred method, but it did not restore normal knee kinematics. Double bundles are considered more anatomical and supportive, especially during rotational loading. It is able to replicate the anteromedial and posterolateral bundles using the gracilis and posterolateral bundles Semiganglion cyst. The single-beam approach (AM part) has been reported to have spinner instability over longer periods of time. [4] To achieve long-term stability, all ligament and capsular constraints are equidistant within the intact ROM. The isometric function of [5] The ACL is achieved through the configuration of its 2 fiber bundles (anteromedial and posterolateral) and their appendages. [6] The ACL is not a single cord, it has bundles of individual fibers that are helical and spread over a broad area of connection. Due to its complex structure The ligament attachment site should not be altered during reconstruction [7].

Techniques for ACL reconstruction

There are two different techniques for ACL reconstruction:

  • Extra-articular
  • Intra-articular

Extra-articular reconstruction

In the 1970s and 1980s, extra-articular surgery was commonly performed on anterior tibial subluxation to remove any pivotal displacement. However, it has fallen out of favor due to residual instability and subsequent degenerative changes. Extra-articular reconstruction has been used for Isolate or add intra-articular reconstruction. Intra-articular reconstruction becomes the first choice, but does not fully restore knee kinematics. [8] Intra-articular reconstruction creates static constraints and is therefore usually accompanied by attachment of the lateral femur Epicondyle of Gerdy’s tubercle, collagen constraint parallel to the intra-articular course of the ACL. This also avoids the problem of insufficient blood supply for intra-articular reconstruction. Most of these procedures use the iliotibial band or the iliotibial band that connects the outside Femoral epicondyle of Gerdy’s tubercle. The optimal attachment point for extra-articular reconstructions with anterolateral rotational instability was found to be Gerdy’s node. This procedure is also primarily used in conjunction with severe anterior intra-articular reconstruction Instability results from injury or late stretching of secondary stable capsular structures or the lateral side of the knee. [9]


  • Maclntosh method (iliotibial band tenodesis)
  • Maclntosh, modified by Loseen method
  • Andrews method


  • Reduces anterolateral rotational subluxation but does not restore normal ACL anatomy and function.
  • High failure rate when used alone.

Intra-articular Procedure

Advances in arthroscopic surgery have resulted in better outcomes in ACL injury rehabilitation. The procedure may involve a facet arthrotomy incision that leaves the medial oblique muscle on the patella. The procedure can use endoscopic techniques or Double incision arthroscopy technique.

Various tissues/grafts have been used to anatomically reconstruct a torn ACL, including parts of the extensor mechanism[10][11] patellar tendon iliotibial band[12][13] semitendinosus tendon[14][ 15] Gracilis tendon [16] and meniscus [17]. These can all be used in autografts, i.e. grafts from those who underwent surgery. Other approaches include the use of allografts and synthetic ligaments. [18][19]. This process has the following steps:

  • Graft selection: The graft to be used depends on the length of the procedure. The most commonly used autografts are patella grafts and hamstring tendon grafts (semitendinosus and gracilis).
  • Diagnostic arthroscopy: performed in conjunction with any necessary meniscal debridement or repair. Note the status of the partial thickness tear displaced handle tear and the articular surfaces including the patellofemoral joint.
  • Graft Harvest: A small incision extending from the distal end of the patella to 2.5 cm below the tibial tubercle is used to obtain the graft. After retracting other structures, the graft to be removed is clearly outlined and a micro-oscillating saw blade is used to harvest the graft/bone plug. a triangular bone A plug profile is usually obtained.
  • Graft Preparation: Grafts are shaped into 10mm tubulars for femoral drilling and 11mm tubulars for tibial tunnels.
  • Intercondylar incision preparation and incision plasty: Perform an incision plasty with a 5.5 mm burr from the front of the intercondylar incision back and from distal to proximal and strip away any residual tissue. Actively debride the tissue with an arthroscopic razor. if in Small intercondylar or incision areas followed by further modifications.
  • Tibial Tunnel Placement: The tibial tunnel should be placed so that the graft does not impinge on the top of the intercondylar notch and should be in the middle third of the anterior ACL insertion site.
  • Femoral Tunnel Placement: Following tibial tunnel placement, femoral tunnel placement is completed for normal ACL-like graft placement.
  • Graft Placement: After tunnel placement, the graft is slid through the tunnel with the arthroscopic grasper. The graft can be rotated before the tibia is fixed.
  • Graft fixation: The graft is then fixed to the bone and tunnel using nitinol needles. The graft can be rotated prior to tibia fixation because the ACL has been shown to have approximately 90 degrees of external rotation within its fibers. The magnitude of the graft tension generated during fixation directly affects Implications for ACL rehabilitation.
  • Wound Closure: Before closing the graft collection site, a bolus injection of 0.25% Macaine was given and injected intra-articularly. The wound is closed with absorbable sutures and the knee is bent. ACL reconstruction is one of the most common orthopaedic procedures and usually involves Degeneration of articular cartilage.
  • Gross collateral ligament rupture and full-thickness cartilage damage were seen on MRI.
  • Patellar tendon surgery: involves the central third of the ipsilateral patellar tendon. Fix the bone fragments in the tibia and femur.
  • Hamstring Tendon Surgery: Four-layer fold of the gracilis and semitendinosus tendons.
  • Surgery was performed 10 weeks after the injury.

Double bundle reconstruction: The semitendinosus is used with autografts through 2 tunnels in the tibia and femur. The autograft method is a bone-to-bone graft using a hamstring/semitendinosus muscle graft. Three tunnels can also be used, 2 through the tibia and 1 through the femur.

The most common procedure for such reconstruction:

  • Autologous bone-to-patella and tendon-to-bone grafts
  • Autologous quad hamstring graft

For bone-to-patella and tendon-to-bone grafts, several bone fragments were taken from the patella and tibial tuberosities. This procedure causes more anterior knee pain than a semitendinosus graft. In the second procedure, the graft is obtained from the distal end of the semitendinosus and Gracilis tendon.

Other procedures are LARS artificial ligament (Ligament Advanced Strengthening System) iliotibial band allograft cadaveric allograft synthetic materials and grafts from living related donors, but all materials have their drawbacks. There is a possibility of cross infection and damage Chronic effusion and recurrent instability of the immune response [20]

Single- and double-bundle ACL reconstruction:

A kinematic study [21] has shown that standard single-bundle ACL reconstruction does not produce the same kinematics as an intact ACL during normal activity. Only the front and rear stability seems to be rebuilt. Abnormal tibial rotation of the knee joint occurs when the leg rotates. single bundle ACL reconstruction does not restore the normal rotation of the knee joint.

In contrast, anterior translation after double-bundle reconstruction was comparable to the intact ACL at 0° of flexion, but the most stable positions of the knee were at 15° and 75° of flexion.

Watch this video to learn more about ACL reconstruction using the patellar tendon


Clinically Relevant Anatomy

Anatomy of the femoral and tibial tunnels:

Femoral tunnel:

The tunnel on the sagittal side of the knee extends to the top of the femoral cortex and intercondylar notch.

Tibial Tunnel:

The tibial tunnel must first be created in a way that prevents the graft from hitting the top of the intercondylar notch. The tibial tunnel should be oriented towards the Blumensaat line. This line starts from the tibial tuberosity and the posterior side should be towards the tibial tuberosity line. flower seed

Which Graft?


Various tissues/grafts have been used for anatomical reconstruction of torn ACLs.

There are 4 types of grafts:

  • Autografts from the patient’s own body, including parts of the extensor mechanism[24][25] Patellotibial band[26][27] Semitendon[28][29] Gracilis tendon[30] and meniscus [31].
  • Allograft: Graft taken from a cadaver. [32][33].
  • Xenograft: A graft taken from an animal. In particular, bovine xenografts are associated with high complication rates [34].
  • Synthetic Materials: These can be further divided into 3 categories of biodegradable (carbon fiber) permanent prostheses (Gore-Tex and Dacron) and ligament augmentation devices.

The most commonly used are autografts (patella and hamstrings) and sometimes allografts. There is no consensus in the literature as to which provides the most stability. [35] Each of these options has advantages and disadvantages.


Patellar Tendon

When a patellar tendon graft is taken, the central 1/3 of the patellar tendon is removed (approximately 9 or 10 mm) and a piece of bone where the patella and tibia attach.


  • Very similar to the structure to be replaced. The length of the patellar tendon approximates the length of the ACL, and the bony end of the graft can be placed in the bony attachment of the ACL.
  • Early bone-to-bone healing takes about 6 weeks. Bone-to-bone healing is considered stronger than soft-tissue-to-bone healing, as with hamstring grafts.


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

Hamstring Tendon


This graft option has become increasingly popular with improvements in multi-bundle graft preparation techniques.


  • The 4-bundle graft is stronger than the patellar tendon.
  • There is no risk of anterior knee pain like the patellar tendon.
  • Smaller incision.
  • Immediate postoperative pain is less.


  • Graft harvesting can be difficult, especially for those with smaller muscles.
  • Attaching the graft to the bone requires additional “hardware,” the screws.
  • Soft tissue-to-bone grafts take longer to heal, 10-12 weeks.
  • Donor site morbidity. The patient may have difficulty regaining full strength in the donor hamstrings. [37]

Allograft (Donor Tissue)

Allografts are most commonly used in patients with lower needs or those undergoing revision ACL surgery. Biomechanical studies have shown that allografts (donor tissue from cadavers) are not as strong as the patient’s own tissue (autologous grafts). However, for many patients ACL reconstruction using an allograft is sufficient for their needs. Therefore, it may be a good option for patients who do not plan to participate in high-demand sports such as football and basketball.


  • Decreased operation time
  • No need to remove other tissue for transplantation
  • Smaller incisions
  • Less post-operative pain


  • Risk of disease transmission.
  • Transplantation reduces the strength of the tissue by killing living cells.
  • Longer graft to bone incorporation time.
  • Not readily available
  • Expensive


Many surgeons have preferred techniques for different reasons. Patellar tendon or hamstring grafts are approximately equal in strength. There is no right answer as to which is best, at least not proven in orthopaedic studies. The strength of the allogeneic tissue is less than Other grafts, but the strength of the patellar and hamstring tendon grafts exceeds that of a normal ACL.

Successful anterior cruciate ligament reconstruction depends on a number of factors, including the patient’s choice of surgical technique, postoperative rehabilitation and associated secondary restraint ligament instability. Errors in the method of tensioning or fixation of graft selection tunnel placement Selection can also lead to graft failure. Comparative studies in the literature suggest that outcomes are similar regardless of the graft chosen. The most important aspect of surgery is tunnel placement, and the choice of graft is accidental. [38]

The 2011 Cochrane Review [39] described the following:

  • All knee stability tests supported patellar tendon grafts.
  • Conversely, people had more pain in the front of the knee and knee discomfort after patellar tendon reconstruction.
  • More people lose the ability to straighten their legs after patellar tendon reconstruction.
  • In contrast, more people had a decreased ability to flex their legs after hamstring reconstruction.

A recent study concluded that ipsilateral autografts continue to show excellent outcomes in terms of patient satisfaction, symptom, functional activity level, and stability. However, the use of HT autografts did show better outcomes than PT autografts in all of these outcome measures. also After 15 years, ACL reconstructed with HT grafts showed a lower incidence of radiation osteoarthritis [40].

Outcome Measures

  • International Knee Documentation Committee Subjective Knee Table (IKDC)
  • Knee Injury Osteoarthritis Outcome Score (KOOS)
  • Tegner Lysholm Knee Scoring Scale

Physiotherapy Management

Anterior Cruciate Ligament (ACL) Rehabilitation


  • What are the best graft options for ACL reconstruction?
  • A randomized trial in the treatment of acute anterior cruciate ligament tears
  • The anterior cruciate ligament was reconstructed with a synthetic abrasive sheet. literature review

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