Free Bone Plug Quadriceps Tendon Harvest and Suspensory Button Attachment for Anterior Cruciate Ligament Reconstruction

Abstract

The most commonly used autografts for anterior cruciate ligament reconstruction are the bone–patellar tendon–bone and hamstring tendons. Each has its advantages and limitations. The bone–patellar tendon–bone autograft can lead to more donor-site morbidity, and the hamstring autograft can be unpredictable in size. The quadriceps tendon, with or without a bone block, has been described as an alternative graft source and has been used especially in revision cases, but in recent years, it has attracted attention even for primary cases. We report a technique for harvesting a free bone quadriceps tendon graft and attaching an extracortical button for femoral fixation for anterior cruciate ligament reconstruction.

The most commonly used autografts for anterior cruciate ligament (ACL) reconstruction are the bone–patellar tendon–bone and hamstring tendons. Recently, there has been an increase in interest in the quadriceps tendon as an autologous graft option for ACL reconstruction.¹ Among the proposed advantages are low morbidity at the harvest site2, 3, 4; predictable size and great versatility; and the ability to harvest grafts in different widths, thicknesses, and lengths.⁵ The quadriceps tendon graft can be harvested with6, 7 or without a bone block.⁸ To completely avoid possible patellar fracture and reduce morbidity at the harvest site, a free bone plug graft is the solution. We present our preferred method of free quadriceps graft harvest for ACL reconstruction and describe how we use a suspensory fixation device for femoral fixation with this type of graft. The harvest method is based on the technique described by Fulkerson and Langeland,⁹ but to our knowledge, the cortical button technique has not been described previously.

Surgical Technique

Under general or spinal anesthesia, the patient is positioned supine on the operating table and the knee flexed to 90°. The skin incision starts from the proximal pole of the patella and extends proximally, in a longitudinal midline fashion, for about 3.5 to 4 cm (Fig 1). After skin and subcutaneous fat incision, the underlying quadriceps tendon is visualized. Medial dissection is carried out until the fibers of the vastus medialis oblique muscle can be seen. The first incision in the tendon starts 1 cm lateral to the vastus medialis oblique muscle at the proximal pole of the patella and runs about 4 cm proximally. The surgeon should try not to incise into the suprapatellar pouch. We prefer harvesting partial-thickness graft, usually using a 7-mm-deep incision. The depth of the No. 10 scalpel blade is 7 mm and can be used as a reference for this¹⁰ (Fig 2). The next incision starts 10 to 11 mm lateral to the previous incision running parallel. Then, a curved hemostat is introduced into the first incision, through the tendon, and out the lateral incision, thus defining the graft width and thickness (Fig 3). The tendon is first released from the patella by sharp incision, and the hemostat is pushed distally to free the tendon insertion (Fig 4). This end of the graft is whipstitched about 2 cm in a standard fashion using two No. 2 high-strength sutures (Hi-Fi [ConMed Linvatec, Largo, FL] or UltraBraid [Smith & Nephew, Andover, MA]). Then, the dissection is carried proximally, maintaining the depth and width of the graft using the scalpel and scissors and manipulating the graft using the previously placed sutures (Fig 5). After the end of the quadriceps tendon is reached, the release is performed with the scissors. This way, we obtain an average length of the graft of about 9 cm (Fig 6). The proximal part of the graft is then whipstitched in a standard fashion with two No. 5 polyester sutures. Pretensioning of the graft is required to remove slack from the sutures. The high-strength sutures placed initially will be used to attach the extracortical button for femoral fixation (Video 1). We use either an XO Button (ConMed Linvatec) with the appropriate loop dimension or an EndoButton CL (Smith & Nephew). We tie knots using the high-strength sutures through the button loop (4 alternating half-hitches) and then twice around the loop with 3 alternating half-hitches (Fig 7). Tibial-side fixation is achieved with an interference screw.

Fig 1.

Landmarks for the skin incision for harvesting the free quadriceps tendon graft. The proximal pole of the patella is marked, and the skin incision is outlined (arrow). A left knee is shown, with the patient positioned supine and the knee flexed to 90°.

Fig 2.

The depth of the No. 10 scalpel blade measures 7 mm and can be used as a reference for the depth of the incision in the quadriceps tendon.

Fig 3.

A curved hemostat is placed through the medial incision in the quadriceps tendon, through the tendon at the desired depth, and out the lateral incision. This defines the thickness and width of the graft. A right knee is shown, with the patient positioned supine and the knee flexed to 90°.

Fig 4.

After the release of the quadriceps graft from the patellar insertion with the scalpel, the hemostat is pushed distally to complete the release. A left knee is shown, with the patient positioned supine and the knee flexed to 90°.

Fig 5.

By use of the whipstitched sutures placed in the distal end, the graft is manipulated and the dissection is carried out proximally with the scissors. A left knee is shown, with the patient positioned supine and the knee flexed to 90°.

Fig 6.

Free bone quadriceps tendon after harvest on the back table; it measures 9 cm in this case. High-strength sutures are seen whipstitched on one end.

Fig 7.

Knots are tied through the button loop with the high-strength sutures placed initially to secure the button to the graft. We recommend placing 4 knots through the loop in alternating fashion and then 6 knots around the loop also in alternating fashion to achieve a very secure fixation.

Discussion

Our technique has several advantages (Table 1). The quadriceps tendon is consistent in size, having the anatomic characteristics to produce a graft whose length and volume are both reproducible and predictable.¹¹ Using a free bone–harvesting technique eliminates the risk of iatrogenic patellar fracture and has minimal donor-site morbidity. This technique does not require any special instruments and is relatively minimally invasive. The extracortical button fixation described is very secure and time-saving. There are also some risks and limitations with this procedure that should be taken into consideration. During the harvesting part of the procedure, there is a risk of penetrating the joint. If this happens, the fluid will leak during the arthroscopy. This is not a serious problem; in our experience the arthroscopy is not impaired by this. However, using the No. 10 scalpel blade for incising the quadriceps tendon during harvest can help maintain a constant depth and avoid this complication because the blade depth is 7 mm. If the joint is penetrated, the defect in the suprapatellar pouch can be repaired with a resorbable suture after the graft is harvested. In addition, there is a potential risk of harvesting an incomplete graft that is too short. During the learning curve, we recommend making a slightly longer skin incision to see and measure the length of the graft before making the proximal, final release. The minimum length recommended is 7 cm. If these pearls are adhered to, complications should not be encountered (Table 2). After observing excellent results with this technique, we are using it as our main graft option in primary ACL reconstruction.

Table 1.

Advantages of Our Procedure for Anterior Cruciate Ligament Reconstruction

The quadriceps tendon is consistent in size (width, length, depth).

The harvest technique is straightforward and requires no special instruments.

Minimal morbidity is seen at the harvest site.

There is no additional risk of patellar fracture.

The extracortical button fixation described for the femoral side is very secure.

Table 2.

Technical Pearls and Pitfalls

Pearls

Accurate landmark identification is required for skin incision, using the proximal pole of patella with the knee flexed to 90°.

Medial dissection is performed until the VMO fibers are seen.

The first incision in the tendon is the medial incision; it should be made about 1 cm lateral to the VMO.

The surgeon should use a No. 10 scalpel blade to perform the incisions in the tendon; its 7-mm depth can be used as a reference.

The surgeon should measure the length of the graft before releasing proximally.

Careful pretensioning of the sutures is required to prevent button displacement after the knots are tied.

Pitfalls

Penetration of suprapatellar pouch during graft harvest and fluid extravasation during arthroscopy

Graft harvested with inadequate length, width, or depth

Button displacement from sutures

VMO, vastus medialis oblique.

Supplementary Data

Video 1

Technique for harvesting a free bone quadriceps graft for anterior cruciate ligament reconstruction and attachment of a suspensory device for femoral fixation. The operation is shown in a left knee. An intra-articular view is shown in a right knee (starting at 3:18) with the 30° arthroscope in the anterolateral portal.