Abstract
Background:
Hamstring tendon (HT) autograft for anterior cruciate ligament (ACL) reconstruction has shown equivalent graft failure rates to bone-patellar-tendon-bone (BTB) with decreased prevalence of anterior knee pain. It should be noted that young athletes, particularly females athletes, may have increased graft failure rates with HT versus BTB. Additionally, HT graft diameters <8 mm have shown worse patient-reported outcomes and higher graft failure rates. Five-strand HT autograft offers a method to increase graft size without utilization of allograft tissue or synthetic material.
Indications:
This presentation describes the technique for 5-strand HT autograft reconstruction of the ACL. Tips and tricks on graft prep, tunnel placement, tunnel depth, and avoiding pitfalls in surgery are provided.
Technique Description:
Gracilis and semitendinosus tendon harvest is performed through an L-shaped flap of sartorial fascia. If the 4-strand configuration is <8 mm, the semitendinosus is tripled for a 5-strand configuration. Graft is attached to a 15-mm fixed-length button construct for femoral fixation. The tibial tunnel is typically drilled with the guide through the accessory anteromedial portal. Independent femoral tunnel drilling is then performed via the accessory anteromedial tunnel with the knee in hyperflexion, using an offset guide to aid in tunnel placement. Femoral tunnel is initially reamed to depth of 25 mm and then drilled through the far cortex with a 4.5-mm drill to allow for suspensory fixation. Total length to the lateral cortex is measured and reaming of the tunnel is performed to achieve a 5- to 7-mm difference between total tunnel length to the lateral cortex and reamed tunnel length, assuring room for the button to flip on the femoral cortex. Tibial fixation is achieved by interference fixation versus tying the free suture limbs over a post with a washer.
Results:
Recent studies show the HT autograft to have similar re-rupture rates for ACL reconstruction compared with other autograft options. Additionally, this option has low donor-site morbidity and has demonstrated significant less anterior knee pain and kneeling pain postoperatively.
Discussion/Conclusion:
ACL reconstruction with 5-strand HT autograft has shown to be an effective method to increase the graft diameter with low rates of donor-site morbidity.
This is a visual representation of the abstract.
Keywords
Video Transcript
In this video, we present our technique for an anterior cruciate ligament (ACL) reconstruction with a 5-strand hamstring tendon autograft utilizing both the gracilis and semitendinosus tendons.
The goal of this video is to describe a surgical technique to increase graft size when using hamstring tendon autograft for ACL reconstruction. This description also includes tips and tricks on graft harvesting, graft prep, tunnel management, and graft fixation.
Graft selection is part of the preoperative discussion with all patients electing to proceed with ACL reconstruction. Use of allograft is generally avoided given higher re-rupture rates. Bone-patellar tendon-bone autograft, quadriceps autograft, and hamstring tendon autograft options are discussed with each patient. Numerous studies have demonstrated similar re-rupture rates between these options. However, hamstring tendon autograft is typically not utilized in patients with generalized ligamentous laxity. The hamstring tendon autograft is typically the preferred option in patients who perform repetitive kneeling activities, where the increased anterior knee pain with alternative graft options may have a greater effect on postoperative satisfaction.
Conversion to a 5-strand configuration has shown reproducible diameter increase. This is important as research has shown improved patient-reported outcomes and graft rupture rates with diameter >8 mm.
In this case, we present a 25-year-old recreational soccer player who presented to clinic 3 months after feeling a “pop” with a noncontact knee injury resulting in immediate pain and knee swelling. Examination demonstrated neutral alignment, mild effusion, slight restriction of range of motion of 2° to 135°, positive Lachman, and medial joint line tenderness. X-ray did not demonstrate any significant osseous abnormalities. Magnetic resonance imaging (MRI) showed typical pivot shift bone bruising pattern with complete rupture of the ACL. Additionally, a bucket-handle tear of the medial meniscus was identified.
For the ACL reconstruction, the patient is placed supine with a sandbag taped to the end of the operating bed to allow the knee to be in 90° of flexion. A lateral post is placed at the proximal thigh. No tourniquet is used. Examination under anesthesia confirmed positive Lachman, and pivot shift was limited by the bucketed meniscus. A total of 10 mL of 1% lidocaine with epinephrine is injected at the portal sites and hamstring tendon harvest site.
Incision is made on the anteromedial proximal tibia, centered over the palpable hamstring tendons. Bovie electrocautery is used for hemostasis, and medial and lateral flaps are elevated superficial to the sartorial fascia. Location of the gracilis tendon is palpated, and the horizontal limb of the upside-down L-shaped flap of sartorial fascia is created just proximal to the gracilis with bovie electrocautery. The vertical limb is created off the medial border of the tibial crest, and the sartorial fascia is elevated to identify the adherent gracilis and semitendinosus tendons.
A right-angle clamp is used to develop the plane between the gracilis and sartorial fascia, which is often more apparent proximally. The gracilis is bluntly separated from the sartorial fascia with the right-angle clamp, and a second clamp is used to grasp the gracilis as distally as possible. Metzenbaum scissors are then used to cut the tendon free from the sartorial fascia distally. Heavy nonabsorbable #2 suture is then used to whip stich the end of the tendon. The gracilis is the freed of any adhesions using a Metzenbaum scissors. Once freed, the sutures are held by the assistant, while the semitendinosus tendon is prepared.
Similar steps are taken for semitendinosus harvest. When harvesting the semitendinosus, care must be taken to verify that all adhesions to the medial head of the gastrocnemius have been fully freed, or the graft may be amputated short during harvesting. Digital palpation, in addition to pulling on the graft and verifying the medial head of the gastrocnemius does not get pulled, can aid in confirmation that the graft is adequately free.
Once both grafts have been freed of attaching bands, and a tendon stripper is then used to first harvest the gracilis tendon and then the semitendinosus tendon. While utilizing the tendon stripper, focus on pushing the tendon stripper over the tendon as opposed to pulling the tendon through the stripper. Tendons are placed in a solution containing normal saline and vancomycin. A red-rubber catheter is inserted along the hamstring tendon tract and 20 mL of 0.25% bupivacaine is injected. The sartorial fascial flap is then closed with absorbable suture.
Muscle tissue is removed from the tendons utilizing a large curette. The gracilis and semitendinosus are then doubled over a Ethibond (Ethicon; Blue Ash, OH) suture to measure the diameter of a 4-strand hamstring autograft. This was measured to be <7.5-mm, and decision was made to triple the semitendinosus to create a 5-strand configuration. The semitendinosus was measured to be 27-cm in length.
The semitendinosus was then attached to the graft prep stand. A nonabsorbable suture tape was whip stitched on the proximal end of the tendon. The semitendinosus was then placed in the saline vancomycin solution while the gracilis tendon was prepared on the graft prep stand by whip stitching a nonabsorbable #2 suture on the proximal end of this tendon starting at the 18-cm mark and working toward the distal end of the tendon, as this is two-thirds the distance of the measured semitendinosus graft.
The button with a 15-mm loop is then secured to the graft prep stand, and the suture tape portion of the semitendinosus is tied securely to the loop of the button. The free end is then brought through the loop. An Ethibond suture is then passed through the loop created in the tendon to tension this limb. The doubled-over portion of the tendon and the free end of the tendon are then equalized in distance and secured to the graft prep tensioner. The doubled-over end of the semitendinosus tendon is then whip stitched together. The gracilis tendon is then brought through the loop, and the limb lengths are equalized and should match the lengths of the semitendinosus limbs. The Ethibond suture, used to tension the doubled-over portion of the semitendinosus, is removed and all limbs of the semitendinosus and gracilis are tensioned together.
A 2-0 Vicryl absorbable suture is then used to tubularize the graft. The graft is then removed from the tensioner, and final diameter is determined. The graft is measured to be 8 mm on the femoral side and 8.5 mm on the tibial side with 9.3 cm of tendon length. The graft is held under tension and a vancomycin-soaked gauze is placed over the graft until use later in the case.
A proximal medial outflow trocar is placed and a high and tight anterolateral portal is established. Arthroscopic examination is performed. Displaced bucket-handle medial meniscal tears is noted with the bucketed component of the meniscus identified within the notch. Anteromedial portal is established, and a shaver is utilized to debride the ligamentum mucosum and fat pad to aid in visualization. The arthroscopic trocar is utilized to reduce the bucketed meniscus.
The remainder of the arthroscopic evaluation demonstrated complete femoral sided ACL disruption. The lateral compartment was intact without meniscal or cartilage pathology. The arthroscopic shaver and radiofrequency probe are utilized to debride the ACL stump. Close attention is paid to avoid iatrogenic damage to the posterior cruciate ligament and the posterior lateral meniscal root. The position of the tibial footprint is marked with the radiofrequency probe utilizing the ACL stump as well as the anterior horn of the lateral meniscus for reference.
Accessory anteromedial portal is created with needle localization. Excess fat pad is resected to allow passage of instruments. Tibial drill guide is inserted through the accessory anteromedial portal. The tibial guide is typically set to approximately 40-mm tunnel length, with adjustments made for longer or shorter grafts, and the guide pin is advanced to the tip of the drill guide. Position of the guide pin is visually inspected for appropriate medial-lateral and anterior-posterior positioning.
The knee is brought into extension and the position of the guide pin in relation to the top of the notch is also assessed. A lateral fluoroscopic view is obtained to confirm appropriate anterior to posterior pin placement and alignment with Blumensaat’s line. With a large curette covering the tip of the guide pin, an 8.5-mm reamer, matching the graft diameter, is passed on power over the guide pin. Shaver is used to debride soft tissue followed by an 8.5-mm dilator. An arthroscopic rasp is then used to smooth the posterior edge of the tunnel.
The femoral tunnel is then drilled through the accessory anteromedial portal using an offset guide that will allow a 1- to 2-mm back wall following tunnel drilling. In this case, we utilized a 5-mm offset guide. With the knee in approximately 90° of flexion, the guide is hooked behind the lateral femoral cortex at approximately the 2 o’clock position in a left knee. The knee is then hyper-flexed and a fluted-tipped beath pin is used to mark the proposed site of femoral tunnel drilling. Knee is brought back to 90° of flexion, and the arthroscope is placed through the anteromedial portal to assess tunnel placement.
Tunnel position was found to be slightly high and was adjusted to a slightly lower position with the offset guide. Beath pin was then passed through the lateral cortex and out the skin. An 8-mm, half-fluted, reamer was then used to ream the femoral tunnel to a depth of 20-to-25 mm. The beath pin is then over drilled with the 4.5-mm drill bit. Bone debris was removed, and the tunnel length was measured. In this case the tunnel measurement was 32 mm. We then utilized an 8-mm full-fluted acorn-tip drill bit to drill to a final depth of a little over 25 mm. Leaving slightly less than 7 mm between the depth of the tunnel and the lateral cortex, which provides the distance needed to flip the button when using a 15-mm rigid loop button device.
Medial meniscus tear was fixed in using an inside-out technique. Pie-crusting of the medial collateral ligament (MCL) was performed to avoid iatrogenic damage to the articular cartilage and facilitate visualization to ensure anatomic meniscal reduction and repair.
Graft is marked at the total femoral tunnel length, in this case 32 mm from the button. A second line is placed 7 mm from this, in this case 39 mm from the button, signifying the position at which the button will flip.
Ethibond suture is then passed through the femoral tunnel using a beath pin. The looped end is retrieved through the tibial tunnel. The green and white sutures of the button are then passed through the knee joint. The white sutures are used as the leading suture, and the graft is pulled through the tibial tunnel into the femoral tunnel. Once the graft is fully pulled into the femoral tunnel, the button is flipped on the lateral cortex, and toggle of the button can be felt. Once flipped, the graft is tensioned on the tibial side and the toggle on the button should disappear confirming the button has flipped.
The graft is then cycled through full range of motion 20 times, and graft isometry is assessed. The graft was then fixated on the tibial side using a 9.0-mm Intrafix (Innovasive Devices, Mitek, Westwood, MA, USA). If the free ends of the graft are not visualized exiting the tibial tunnel, the sutures are tied over a post with a washer.
For postoperative recovery, the patient was made weightbearing as tolerated in a hinged knee brace locked in extension for weight bearing for the first 4 weeks due to the meniscal repair. Range of motion restricted to 0° to 90° for the first 4 weeks. Patient is then progressed through a standard ACL protocol with return to sport typically restricted to no sooner than 9 months postoperatively, in addition to meeting return to sport testing criteria administered by physical therapy.
With this technique, complications are rare. Taking care to make sure all soft tissue adhesions are taken down prior to graft harvest assures graft is not prematurely transected. Initial femoral tunnel reaming is kept to 20 to 25 mm to avoid breach. If the lateral cortex is breached, then alternative fixation methods should be utilized.
Great care is taken in verifying tunnel placement. On the femoral side, we place the camera through the anteromedial portal and visualize the marked tunnel placement in reference to the posterior border of the femoral condyle and articular surface. This is done in 90° of knee flexion so that it is reproducible, and the anatomy is consistent. Additionally, the anterior horn of the lateral meniscus is commonly described for aiding in tibial tunnel placement. However, variability exists with this and thus fluoroscopy is utilized to confirm placement. Utilizing the mini C-arm takes less than a minute and can also be used to confirm button deployment if any question exists.
Benefits of this technique include the predictable diameter increase from the 4-strand hamstring autograft. And though adjustable loop buttons exist, we elect to use fixed loops as we have the benefit of knowing how far the button is going past the lateral cortex utilizing marks placed on the graft, assuring the button is not being pulled into the soft tissue. We also are given tactile feedback of the button flipping and the loss of toggle with tension on the tibial side of the graft confirms the button has flipped. If possible, we prefer interference fixation on the tibial side; however, this is not always possible, and we elect to tie the suture ends over a post and washer providing a stable and very economic fixation option.
Similar graft failure rates with hamstring tendon autograft compared with bone-patellar tendon-bone autograft have been shown, even in elite soccer athletes. Several studies have also shown the importance of achieving a graft diameter of at least 8 mm. When using the 5-strand technique to increase graft diameter, no difference in failure rate has been shown compared to quadrupled grafts >8 mm in diameter. Additionally, decreased rates of anterior knee pain have been shown compared with bone-patellar-tendon-bone autograft. It is worth noting that some reports have shown higher failure rates in young athletes, notably female athletes, as well as those with generalized ligamentous laxity.
