What are ACL Graft Choices?

There are several tendon graft options for patients undergoing anterior cruciate ligament (ACL) reconstruction. The first choice is deciding whether the graft is harvested from the patient (autograft) or harvested from a cadaver (allograft). Several factors will affect the choice of which graft to use, particularly patient age and activity level. In the past, many surgeons utilized allografts for most patients undergoing ACL reconstruction, but these were found to fail at a higher rate. Therefore, in the last decade, autografts have been more frequently used, as they yield better results compared to an allograft.

Autograft tendon choices for ACL Reconstruction include:

• Patellar tendon – Harvesting the central third of one’s patellar tendon has long been used for ACL reconstruction and has a history of long term success. However, because the patellar tendon is a short tendon, a portion of the bone of the knee cap and a portion of the bone of the tibia have to be harvested along with the tendon. Because of this, there is a higher incidence of pain with kneeling in someone who has had their ACL reconstruction with a patellar tendon graft. There is also a slightly higher risk of sustaining a patella fracture after surgery following this graft harvest because the patella has been weakened.
• Hamstring tendon – The hamstring tendon autograft is another good choice for ACL reconstruction. One or two of the hamstring tendons, namely the semitendinosus and usually the gracilis tendons are commonly harvested. These tendons are then doubled over to create a 4 stranded graft (although there are ways to create up to a 6 stranded graft which is even larger in diameter). Like the patellar tendon, this graft has demonstrated good results. However, there can be some residual hamstring weakness particularly with hip extension and terminal knee flexion. In addition, this graft is more prone to re-tear or stretch out compared to other graft choices, especially in female athletes.
• Quadriceps tendon – Harvesting the central part of the quadriceps tendon is a very good graft choice and Dr. Cunningham’s preferred graft for the last 10 years for several reasons. The quad tendon is nearly twice as thick as a patellar tendon, thus making it stronger. The quad tendon is a longer tendon than the patellar tendon, and thus there is no need to take a section of bone from the patella or tibia, resulting in less kneeling pain long term. The quad tendon can also be harvested through a smaller incision compared to a patellar tendon. Finally, the quad tendon is a stiffer and a stronger graft than a hamstring tendon graft, thus being less likely to stretch out or re-tear. For a quad tendon ACL reconstruction, the reinjury rate is 2 – 3%, compared to 13 – 23% for hamstring ACL reconstructions.

What is a Quad Tendon Graft?

Anterior cruciate ligament reconstruction with quadriceps tendon autograft is a great autograft option for many patients. For over a decade, the ACL Doctor, Dr. Richard Cunningham, has utilized the quadriceps tendon for ACL reconstruction almost exclusively in his practice. Numerous orthopedic studies support the quad tendon graft technique in comparison to both patellar tendon and hamstring tendon autografts for ACL reconstruction.

There are many benefits of a quad autograft including:

• High success rate compared to all other graft options
• Very low reinjury rates compared to hamstring grafts
• Thickest, strongest graft option.  Twice the cross-sectional area of a patellar tendon graft
• Equal success rate to patellar tendon, but with a lower incidence of kneeling pain and a smaller incision
• Excellent results for athletes who do high demand sports and activities

What is a Hamstring Tendon Graft?

Hamstring tendon autograft for ACL reconstruction is completed by harvesting the patient’s semitendinosis and gracilis tendons. These tendons are then doubled over, resulting in a 4 stranded graft. There are also techniques to create a 5 or 6 stranded hamstring graft. The results of ACL reconstruction with a hamstring graft are good. However, there may be prolonged hamstring weakness. In addition, there is a higher incidence of hamstring graft stretching or retears.

What is a Patella Tendon Graft?

Patella tendon autograft for ACL reconstruction is completed by taking the middle one-third of the patella tendon along with a one inch long bone plug taken from the patella and another bone plug taken from the tibia and left attached to each end of the tendon.  This graft has historically been used in young athletes who compete in high level cutting and pivoting sports as well as in professional athletes with good results. A larger incision along the anterior aspect of the knee is required to harvest this graft compared to a quad harvest.  There can be some residual numbness along the anterolateral aspect of the knee due to the incision cutting some small, superficial sensory nerve fibers.  The most common complaint with bone-patellar tendon-bone grafts is pain along the front of the knee with kneeling and this pain may be permanent.

Quad Tendon Graft vs. Hamstring Graft

Making the decision between a quadriceps tendon autograft versus a hamstring tendon autograft versus a patella tendon autograft, is done with the expertise of the ACL surgeon and the patient’s input. There are several factors that may impact the graft choice.  These include the patient’s age, patient sex, activity level, lifestyle, and post-surgical expectations. Dr. Cunningham utilizes primarily quad tendon in his practice. However, in older patients (over the age of 55), an allograft may be considered. In young athletic females of smaller stature, a hamstring graft would be suboptimal as the hamstring tendons may be too small in diameter to afford a good, strong graft. In patients who kneel a lot in their sport or work (ie. a carpenter), a patellar tendon would be discouraged given the higher incidence of kneeling pain with this graft choice.

Coupled with a high rate of success with ACL reconstruction using a quad tendon graft, the benefits of a quad tendon harvest are:

• No bone plug required compared to patella tendon graft
• Minimally invasive incision over the harvest site
• Thicker graft, and greater cross-sectional area
• Reduced complications (ie. a lower incidence of patella fracture than a patellar tendon graft)
• Flexibility on determining graft length that is required during the harvest

For ACL surgery patients, the quadriceps tendon graft is a good alternative with distinct biomechanical and recovery advantages.

How Long is Recovery Take After ACL Surgery?

Patients are instructed to ice and elevate the knee for the first few days after surgery, but physical therapy is started immediately after surgery. Patients will get up on crutches with a physical therapist in the recovery room. A hinged knee brace is used to support the leg until the musculature can support the knee. Patients can remove their dressings and take a shower over the wound sites 3 days after surgery. A post-op office visit occurs with Dr. Cunningham within 7-10 days.

Outpatient Physical therapy is prescribed with patients going 2-3 days per week immediately after surgery. In addition to PT, patients will also do a home exercise program, to maximize the rehabilitation timeline. Patient compliance during the recovery process will help ensure complete healing and an optimal outcome. Initially, PT is focused on restoring knee range of motion and reducing swelling. A patient will remain in the post-operative knee brace until they are able to achieve acceptable quadriceps activation and control which typically takes 2-3 weeks. Patients ride a stationary bike within 1-2 weeks from surgery. At 6 weeks from surgery, some gentle quad strengthening is begun. Patients can ride a bike outdoors at 3 months and start running at 4 months. A full return to high level cutting and pivoting sports may take 9 months.