Your own tendons are the usual source of a new ligament in an ACL reconstruction. The three main options are the hamstring tendons, the patellar tendon and the quadriceps tendon above your kneecap.
The quadriceps tendon is a strong, thick graft that can be harvested through a small incision. Studies comparing it with other grafts have generally found similar failure rates, and it can be a useful choice in particular situations.
At a Glance
- In Australia, the hamstring tendons are the most common ACL graft, followed by the patellar tendon.
- The quadriceps tendon is broad and long, so the graft size is more predictable than with hamstrings.
- It tends to cause less pain at the front of the knee and less trouble kneeling than a patellar tendon graft.
- Rehabilitation needs to focus on restoring quadriceps strength.
- It may be preferred with an MCL injury, in hamstring-dominant sports and in revision surgery.
What graft options are there for ACL reconstruction?
The most common graft choice for an ACL reconstruction in Australia is the hamstring tendon graft. Usually two hamstring tendons, the gracilis and semitendinosus, are harvested and combined to form the new ligament.
A less common choice is the patellar tendon. The central part of the tendon is harvested with a block of bone from the kneecap and the shin bone. This graft is strong and has a low re-rupture rate in many studies. However, it can cause pain at the front of the knee, difficulty kneeling and numbness near the incision, and it can weaken your ability to straighten the knee.
What are the benefits of a quadriceps tendon graft?
The quadriceps is the main muscle group at the front of your thigh. Its four muscles join to form the quadriceps tendon, which attaches to the top of your kneecap.
A quadriceps tendon graft uses a central strip of this tendon. Sometimes a small block of bone is also taken from the top of the kneecap.
Because the quadriceps tendon is broad and long, the graft size can be planned using sizing instruments. Hamstring graft size is less predictable, and small grafts can occur even in well-built people.
The quadriceps tendon is often compared with the patellar tendon. Its tissue is reported to contain about 20% more collagen fibrils, the scaffold of the graft. Because the quadriceps tendon is much larger, harvesting a graft weakens it proportionally less, and people tend to have less pain at the front of the knee. Quadriceps weakness can still occur, so rehabilitation focuses on restoring the strength to straighten the knee.
The graft is taken through a small incision above the kneecap. Pain at the harvest site and kneeling tend to be less troublesome than with a patellar tendon graft. A graft diameter of more than 8 mm is readily achieved, and larger grafts have been associated with a lower risk of re-injury.
When does Dr Vishal Pai consider a quadriceps tendon graft?
When the medial collateral ligament (MCL) is also injured
The MCL stabilises the inner side of the knee, and the hamstrings also help support this side. If you have both an ACL and an MCL injury, Dr Vishal Pai may use a quadriceps graft so that the hamstrings are preserved.
If you play a hamstring-dominant sport
The hamstrings are important for sprinting, jumping and kicking. If you regularly take part in these activities, it can make sense to preserve the hamstrings and use the quadriceps tendon instead.
If you need revision surgery after a previous ACL graft has failed
Revision ACL surgery has traditionally used a patellar tendon graft, which has the drawbacks described above, although its bone blocks can be useful in some revision situations. Some surgeons use hamstrings from the uninjured knee. Dr Vishal Pai prefers not to reuse the same type of graft in revision surgery, because the quality of the original graft may have contributed to its failure. The quadriceps tendon is an alternative that also avoids harvesting tissue from the uninjured knee.
These are Dr Vishal Pai’s preferences rather than universal rules. The best graft for you depends on your injury, activities and anatomy.
Summary
The quadriceps tendon is an autograft option that uses your own tissue to reconstruct the ACL. Studies comparing graft types have generally found similar failure rates, although results vary between studies and patient groups. It is a reasonable alternative to discuss when choosing your graft.
If you would like to discuss how this applies to your knee, you can book a consultation with Dr Vishal Pai.
Choosing a graft for your ACL reconstruction?
Dr Vishal Pai performs ACL reconstruction with hamstring, patellar tendon and quadriceps tendon grafts. He can discuss each option and tailor the choice to your knee and activities.
Written by Dr Vishal Pai
Vishal is an experienced knee surgeon based in Bayside, Melbourne. He consults at Sandringham Orthopaedic Specialists and operates at The Avenue Hospital and Calvary Holmesglen Private Hospital. His practice focuses on sports knee surgery, including ACL reconstruction and meniscal repair, as well as robotic knee replacement.