Paratenon-Sparing Quad Tendon Graft Harvest

Abstract

Background:

In recent years, the quadriceps tendon has gained popularity for primary anterior cruciate ligament (ACL) reconstruction surgery due to its robustness, easy access, and ability to be tailor-made to each patient. However, concerns remain regarding potential complications associated with quadriceps tendon harvest, including impaired healing and damage to the extensor mechanism.

Indications:

Preserving the quadriceps paratenon, which is a source of blood supply, nutrients, and therapeutic cells during ACL reconstruction surgery, may improve postoperative outcomes by mitigating potential adverse effects associated with quadriceps harvest. As a result, it may also facilitate the quadriceps healing process and postoperative rehabilitation.

Technique Description:

The incision area is marked approximately 1 cm below to 3 cm above the proximal patellar pole, and the skin is dissected from the underlying tendon, exposing both the quadriceps and its paratenon. Once the tendon insertion to the patella's proximal pole is visualized, a double-blade knife is used to make a full-thickness 2-cm longitudinal cut, taking care not to cut over 2 cm of the overlying paratenon. Then, the distal end of the tendon is safely detached from the patella followed by placing continuous whip sutures, which are then loaded on a graft harvesting system and cannula. The cannula is gently plunged underneath the paratenon while applying tension on the whip sutures with the knee flexed to 90°. Then, the cannula is twisted repeatedly under the paratenon until the desired length of 61/2 to 7 cm is reached. Again, care is taken not to lever the tendon and to harvest it along its anatomic course. Finally, the quad tendon cutter is used to transect the quad at its proximal end. During the procedure, knee extension and flexion are used to aid visualization and access to the tendon's ends.

Results:

Preservation of the quadriceps paratenon during its harvest for ACL reconstruction surgery can potentially improve postoperative outcomes by facilitating healing and reducing friction between the tendon and neighboring tissue.

Discussion/Conclusions:

Preserving the quadriceps paratenon during ACL reconstruction surgery is a technique that can be easily performed and has the potential to improve postoperative outcomes. By preserving the paratenon, surgeons can reduce potential adverse effects associated with quadriceps harvest, such as impaired healing and damage to the extensor mechanism. Based on our experience and the available literature, we believe that preserving the paratenon during quadriceps tendon harvest is a valuable technique that surgeons should consider when performing ACL reconstruction surgery.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Graphical Abstract

This is a visual representation of the abstract.

Video Transcript

The following video presents the surgical technique for harvesting the quadriceps tendon while preserving the paratenon during anterior cruciate ligament (ACL) reconstruction surgery. The procedure is presented by the lead surgeon, Dr Seth Lawrence Sherman, and his team at Stanford University.

Our goal is to present the preservation of the quadriceps paratenon during ACL reconstruction surgery.

In this presentation, we will offer an overview of various graft options, outline the surgical technique involved, and summarize our thoughts on the procedure.

Background and Indications

ACL reconstruction can be performed using either an allograft or an autograft. The selection of the graft type continues to be a subject of significant debate, as highlighted by numerous studies.^1,2,7,9 Within each category, surgeons have various options to choose from, with the 3 main autografts currently utilized being bone–patellar tendon–bone (BTB), hamstring tendons, and quadriceps tendon.^1,3,7,9,14

Each graft option carries its own set of advantages and disadvantages. It is important to consider the patient factors and expectations, as well as the surgeon's skills and preferences.^1,3,7,9,14 While quadriceps tendon autografts have been historically used primarily for revision surgeries, they have recently become a viable choice for primary reconstruction procedures. This shift is attributed to their durability, convenient accessibility, and the ability to customize them according to each patient's needs.^1,3,9 Unlike BTB and hamstring tendon autografts, the surgeon can adjust the graft thickness without requiring folding to control its size. Compared to BTB, the quadriceps tendon has a significantly larger volume, nearly twice the thickness, and eliminates concerns about bone-related complications. However, therefore it does not facilitate bone-to-bone healing.^1,3,9,14

The potential disadvantages and risks to consider during quadriceps tendon harvesting include deviating from the intended route, inadvertently cutting the tendon, or entering the muscle belly.^1,3,7,9,14 This might shorten the tendon or cause muscle damage that can also compromise the extensor mechanism. Additional complications include pain at the graft site, dysfunction or weakness of the quadriceps muscle, numbness at the graft site or lateral side of the knee, anterior knee pain, quadriceps muscle defect, and others.^6,8 Preoperative magnetic resonance imaging (MRI) inspection and assessment of the tendon's course and thickness can help minimize this risk.

The surgical approach, fixation method, and tendon harvest methods may vary because of the quadriceps tendons’ unique anatomy, which consists of 2 distinct superficial and deep layers. This can range from a mid-central incision to a horizontal incision, all-inside fixation versus hybrid fixation, and a partial harvest while preserving a portion of the deep layer to a full-thickness harvest. Each technique has its advantages and disadvantages, allowing for the customization of the graft.^5,8 Theoretically, a partial-thickness graft should mitigate the aforementioned complications but is less robust and has lower biomechanical strength than a full-thickness graft. However, there appears to be no significant difference in outcomes or complications between partial-thickness or full-thickness quadriceps tendon autografts in primary ACL reconstruction. Both types yield successful outcomes with a low graft failure rate and complications.^5,8

Impaired quadriceps healing is another adverse outcome that may lead to delayed rupture during rehabilitation or unfavorable scarring that affects the patella movement, such as patella alta.

Contraindications for quadriceps graft harvest are associated with quadriceps pathologies, including tendinitis, previous trauma to the affected area, and radiation exposure. Actively screening for these conditions can help prevent potential complications.^1,3,9,14

One major contributing factor to tendon healing is an intact paratenon. Similar to other tendons, such as the Achilles tendon, the quadriceps tendon is also surrounded by a paratenon, which is a source of blood supply, nutrients, and cells that contribute to the healing process.^2,4,10-13 Another important function of the paratenon is to reduce friction between the tendon and neighboring tissue. Thus, preserving the paratenon during quadriceps harvest is theoretically important for optimal postoperative outcomes, as it may facilitate healing. We hypothesize that preserving the paratenon can mitigate potential adverse drawback and improves postoperative healing and recovery.

The following video displays the technique of quadriceps tendon harvesting with paratenon preservation during ACL reconstruction surgery. The demonstration depicts a case of primary ACL reconstruction following an acute ACL tear. The patient underwent preoperative physical therapy, achieving full knee extension and 110° of flexion.

Technique Description

During this surgery, we used a standard arthroscopy set, a quad tendon graft harvesting system, and a cannula. The patient was positioned supine in the operating room and received regional block and general anesthesia. Clinical examination showed positive grade 2B Lachman and second-degree anterior drawer test, as well as a grade 2 pivot shift. Prior to draping, the quadriceps route was estimated based on the direction of the quadriceps muscle to aid in the subsequent graft harvest.

The operated leg was then draped in a sterile fashion. An S mark was applied, followed by a tourniquet. Based on the mechanism of injury, clinical examination, and MRI findings confirming a complete ACL tear, the surgical procedure began with harvesting the quadriceps tendon.

The incision area was marked roughly 1 cm below the proximal patellar pole extending 3 cm above in the direction of the quad tendon. Prior to the skin incision, local anesthesia was administered at the intended site, and the operated leg was ranged from flexion to extension to identify the patella's proximal pole.

Next, the skin was dissected from the underlying layers of the tendon using a surgical pad, exposing both the quad and the paratenon. A key elevator can also be used to facilitate the separation.

Once the layers were separated and the quad tendon was visible, the patella's proximal pole and the tendon insertion were palpated and visualized using retractors. The harvest began by employing a double-blade 9-mm or 10-mm knife. Starting at the center of the patella's proximal pole, the blade was placed and gradually moved proximally, creating a 2-cm full-thickness incision from the bone to the quadriceps tendon, eventually plunging underneath the paratenon.

Special attention must be paid to not cutting over 2 cm of the overlying paratenon so that its integrity is not violated. Additionally, visualizing the Q angle and the path of the rectus femoris is crucial during the harvest to minimize the risk of a false route or iatrogenic tear. Taking the knee through extension and flexion can help with visualization and gain better access to the tendon's ends.

Once the full-thickness cut is confirmed, the distal end of the tendon can be safely peeled and detached from the proximal patella using pickups and a knife.

Next, continuous loops of multistranded suture are utilized to create a whip suture, starting proximately 1 to 1.5 cm from the graft's end while ensuring the needle remains secure. During the placement of the whip stitches, it is recommended to shape the tendons as tubular as possible. Better control can be achieved by pulling the suture instead of the needle.

Next, the diameter of the harvested tendon is measured to ensure it is of the desired size. If necessary, the proximal cut can be widened or narrowed accordingly. The needle is then safely loaded onto the graft harvesting system's cannula, plunging it gently underneath the paratenon while applying tension on the whip sutures and stabilizing the knee in flexion to facilitate the harvest.

The cannula is gently twisted repeatedly, in a back-and-forth motion, until the desired length is reached. Attention must be made to harvest the tendon along its anatomic course without leveraging the cannula. Once a length of approximately 61/2 to 7 cm is obtained, the harvest cannula is carefully withdrawn, and a quad tendon cutter is used to transect the proximal end of the tendon. It is crucial to stay on the tendon to prevent any violation of the paratenon or deviating from its path.

The tendon graft is prepared for an “all-inside” technique using an adjustable-loop suspensory device for the femoral side and a button for the tibial side. Additionally, the graft is augmented for internal bracing. During ACL surgery, the outer wound layer is deliberately left open to prevent the accumulation of fluids. A Raytech sponge is then inserted and monitored, allowing for only minimal fluid extravasation. Later, the sutures will be placed to encompass the full thickness of both sides of the tendon, including the paratenon. If additional reinforcement is needed, single sutures can be added. It is essential to avoid forcibly closing the distal end of the tendon to prevent excessive tension, as it may result in scarring and patella alta.

Afterward, we turn our attention to the arthroscopy and ACL reconstruction.

The postoperative protocol is similar to the BTB ACL reconstruction protocols and includes immediate full weightbearing as tolerated using crutches, immediate passive full range of motion, and the use of a knee brace for 6 weeks. The brace is locked until quadriceps control is obtained.

Discussion

To the best of our knowledge, no published literature compares quadriceps harvest with peritenon preservation to nonperitenon preservation. The authors believe this procedure can further improve the healing process and reduce the associated complications such as quadriceps dysfunction or defect. It may also alleviate postoperative pain and expedite rehabilitation time. However, this assumption remains to be investigated.

In summary, the quadriceps tendon autograft is a robust graft that can be successfully used in primary ACL reconstruction and revision surgeries. It can be tailor-made to each patient with a minimally invasive incision. However, a precise surgical technique based on the quadricep's anatomy is crucial to avoid complications and promote optimal healing. Finally, we emphasize the importance of preserving the paratenon to enhance the healing process.

Thank you for your attention.