Quad Tendon Autografts: A Prime Choice for ACL Reconstruction

The optimal tendon for an anterior cruciate ligament (ACL) autograft is still up for debate. Results from the Multicenter Orthopaedic Outcomes Network (MOON) support use of the patellar tendon, especially in young athletes and patients with high-grade laxity. The hamstring tendon is another popular option.

But Cleveland Clinic orthopaedic surgeon and sports medicine specialist Michael Scarcella, MD, says the quadriceps tendon deserves more consideration. While a robust tendon — a good source for an ACL autograft — the quadriceps tendon hasn’t been used or researched as much as other graft sources. In 2010 only 2.5% of ACL reconstructions were performed with the quad tendon. By 2014 the number had increased to 11%, according to a study in Knee Surgery, Sports Traumatology, Arthroscopy. An informal survey of surgeons at a recent national meeting found that quad graft use may be closer to 20% in primary ACL reconstructions.

“The quad tendon’s popularity is slowly increasing,” says Dr. Scarcella, who was introduced to the technique as a surgeon in the U.S. Navy. “After learning from one of my partners who had been using quad tendon autografts for years, I took the plunge and tried the technique on a patient referred to me for revision ACL. It had good results, so I started using quad tendon autografts for primary ACL reconstructions too. Those patients had less postop pain, less longer term anterior knee pain and less numbness. It seemed like they were recovering faster and moving their knees earlier, which was important for an active duty population.”

When Dr. Scarcella joined Cleveland Clinic in 2020, he brought his experience with the technique. Since then, Cleveland Clinic surgeons have been using quad tendon autografts more routinely, including for primary reconstruction.

More favorable tensile properties

Compared to patellar tendons, quad tendons offer a thicker graft with more favorable tensile properties, including:

• Increased load to failure.
• More collagen and higher fibroblast density.
• Stronger remaining tendon after harvest.

MRI demonstrating potential thickness of quad and patellar tendon grafts. Quad tendon thickness = 9.5 mm. Patellar tendon thickness = 4.2 mm

In addition, studies of quad tendon reconstruction have reported less anterior knee pain and numbness at 55-month follow-up, but equivalent stability and functional outcomes compared to patellar tendon reconstruction.

That’s not to say that quad tendon autografts are right for all patients. Graft choice should be individualized, based on imaging and a discussion of the patient’s goals and concerns, says Dr. Scarcella. History of tendonitis or tendonosis in any potential graft tissue is cause to rule it out as a graft option.

Tips for quad tendon autograft surgery

For surgeons considering use of quad tendon autografts for ACL reconstruction, Dr. Scarcella recommends these tips:

• Harvest the full thickness of the tendon. To avoid underharvesting, resulting in a graft that is too small or too thin, harvest the full thickness of the graft and then approximate or repair any defect remaining in the knee joint capsule. Separating the tendon from the capsule is difficult because they are densely adherent, and the graft can be stripped thinner than intended. Taking a full-thickness graft poses minimal extra risk to the patient. Risk of quad weakness or defect is extremely low. Outcomes with full-thickness quad tendon grafts are comparable to those with partial-thickness grafts.
• Gradually work on minimizing harvest-site incision. “Today I harvest the tendon through a 2 cm incision somewhat hidden in skin folds around the knee, but I didn’t start out that way,” says Dr. Scarcella. For a surgeon’s first few quad tendon harvests, allow for greater visibility of the anatomy and orientation of the tendon. When harvesting, it’s important to see the angulation of the medial quadriceps muscle and stay close to the medial border while not penetrating the muscle.
• Prevent hematoma formation with good visualization. Harvest only the tendon. Bleeding can occur if the harvest site inadvertently extends into the muscle.
• Prevent synovial cysts by handling the remaining defect carefully. Close the tendon gap loosely so as not to over tighten the tendon.
• Follow the same postoperative care and rehabilitation protocol as for other autograft techniques. Maintain a straight leg in the postanesthesia care unit, with no pillow under the knee. No brace is needed for isolated ACL reconstruction. Apply compression with a thigh-high thromboembolism deterrent. Use ice and pain medication as needed. Apply weight (with crutches) as tolerated.

Prepped graft, 10 mm thickness.

Harvest incision, 2 cm within natural skin crease.

Strong, reliable and readily available

Over the last five to 10 years, surgical instrumentation has made harvesting tendon autografts easier and more precise.

“We’re getting accurate sizes and quality length, and we have good devices to attach and suspend the graft in place while it heals into or around the bone tunnels,” says Dr. Scarcella. “Quad tendon grafts are strong, reliable, readily available and a lot thicker than the patellar tendon — and can be harvested through a tiny incision. Outside of the biomechanical advantages of the graft and the reduced complications, the smaller harvest site can lead to a more aesthetically pleasing postoperative appearance.”

Seven weeks after quad tendon ACL reconstruction.