Abstract
Background:
Recently, there has been an increase in interest in the quadriceps tendon (QT) as an alternative autologous graft option for primary anterior cruciate ligament (ACL) reconstruction.
Indication:
Anterior cruciate ligament reconstruction in skeletally mature patients (high-risk patients for re-rupture and patients with medial instability).
Technique Description:
The QT graft is harvested with a 4-cm skin incision over the superior pole of the patella. A double knife and an oscillating saw are used to obtain the QT graft with a bone block from the patella (65 mm x 10 mm graft and 15 mm bone block). Then an arthroscopy is carried out with assessment of the ACL tear and treatment of further intraarticular injuries. ACL reconstruction begins with debridement of the femoral insertion to expose the land marks. The medial portal is used for femoral tunnel drilling with the knee in more than 110° of flexion. A special portal aiming device is introduced via the anteromedial portal and a guide wire is placed in the area of the femoral anteromedial insertion. This guide wire is gradually overdrilled with various drills and dilators of increasing size. The final diameter should be 0.5 mm smaller than the diameter of the bone block of the graft to allow for press-fit fixation. Then, the tibial tunnel is drilled using a tibial drill guide leaving the tibial stump of the original ACL intact. The graft is pulled into the joint through the tibial tunnel until the bone block stops at the femoral tunnel entrance. The bone block is then pushed through the medial portal into the femoral tunnel (press-fit fixation). The tibial fixation is performed with an interference screw and optionally with an extracortical button.
Results:
Prior studies with 2 years follow-up have shown that the clinical outcomes in primary and revision ACL reconstruction were not significantly different between the use of QT grafts with femoral press-fit fixation and the use of hamstring grafts with femoral suspension fixation.
Discussion/Conclusion:
Quadriceps tendon bone autograft and femoral press-fit fixation provides an excellent alternative as a graft choice in ACL reconstruction.
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.
This is a visual representation of the abstract.
Video Transcript
My name is Wolf Peterson and in this video, we present the surgical technique for anterior cruciate ligament (ACL) reconstruction with a partial-thickness quadriceps tendon (QT bone autograft and a femoral press fit fixation. We present tips to avoid pitfalls, the rehabilitation protocol, and a short literature review. Wolf Petersen received consultancy fees from Karl Storz endoscopy, and lecture fees from Geistlich, Plasmaconcept, Otto Bock, and Stryker.
Why is there growing interest in the QT as a graft option for ACL reconstruction?
First, its biomechanical properties. A biomechanical study has shown equivalent material properties to the hamstrings and patellar tendons, regarding strength and volume. 9 Second, the graft is predictable in length and diameter, which is not the case with patellar tendon and hamstrings. 5 Third, there is less postoperative weakness in ACL agonists than after harvesting of hamstring tendons, with low donor side morbidity. 2
What is special about this ACL reconstruction technique? First, a femoral press-fit fixation is performed. This fixation technique allows cost-effective femoral fixation and has proven low graft failure and revision rates. 8 Second, a remnant preserving technique is used. Remnant preserving ACL reconstruction is advantageous for graft remodeling and allows preservation of proprioceptive elements. A current meta-analysis has shown better Lysholm score and higher instrumented stability measurement (KT 1000) for remnant preserving ACL reconstruction compared to conventional techniques. 10
What about indication?
The QT is an alternative autologous graft option to patellar tendon and hamstring grafts for all adult patients with an indication for ACL reconstruction. A special indication for the use of the QT as an ACL graft is seen in the case of medial instability, since biomechanical studies have shown that the medial hamstrings have a medial stabilizing function. 4 Another specific indication for the use of the QT in ACL reconstruction could be in young high-risk athletes as a large study of 875 patients has shown that patients treated with hamstring tendon autografts have a significantly higher, activity-dependent risk of revision surgery and experience more ipsilateral graft ruptures when compared with patients treated with QT autografts. 7 In addition, the QT has proven to be a reliable graft source in revision surgery. 2
We do not recommend using the bone block technique shown in this video presentation in children or adolescents with open growth plates, in revision cases with femoral tunnel widening of more than 11 mm and in revisons with a failed QT graft.
This clinical case illustrates our indications for this surgical technique. Our patient is a 22-year-old male soccer player, who had a noncontact knee injury with a complete rupture of the ACL and a distinctive bone bruise at the lateral femoral condyle and posterior tibial plateau. There was no associated meniscus or cartilage damage. On clinical examination under anesthesia, he had slightly restricted range of motion with a grade 3 Lachman and positive pivot shift.
Preoperative planning includes the reservation of a 1-hour surgical time slot, checking for allergies since preoperative antibiotic treatment with cephazoline or a substitute antibiotic in case of allergy is recommended. In revision situations or in patients with grade 3 pivot shift, an additional anterolateral tenodesis should be planned.
For positioning, the leg is placed in an electric mobile leg holder, which allows different angles of flexion during surgery. For medial portal drilling, a flexion angle of >110° is necessary. For drilling of the tibial tunnel, the knee should be in approximately 45° of flexion to get a better overview about the tibial ACL insertion.
If the indication for ACL reconstruction is clear based on patient’s history, clinical examination and MRI, surgery starts with harvesting of the QT graft
For graft harvesting, a 4-cm skin incision is made from the upper pole of the patella proximally. After exposure of the tendon, a double-bladed scalpel is used to make 2 parallel incisions 10-mm apart, 6 mm deep, and 65 mm long. Thickness of the graft is determined by a 5-mm tendon separator which is gently pushed proximally to the desired length of approximately 65 mm. Then the tendon graft is cut subcutaneously with a tendon cutter.
The proximal end of the graft is reinforced with a baseball stitch, which later allows a tibial suspensory fixation.
An oscillating saw is used to harvest a conical bone block of a length of approximately 15 mm from the patella. A small hole is drilled into the distal part of the bone block which serves to accommodate a holding and pulling thread. The total length of the QT bone graft is 80 mm.
The transition between bone and tendon is marked with blue color.
A tendon thickness tester is used to check if the complete graft slides through a 10 mm tunnel and if the bone block jams in a hole with a diameter of 9 or 9.5 mm. If not, the bone block is trimmed with a forceps.
Finally, the tendon defect is closed with a resorbable suture
After a diagnostic arthroscopy via a high anterolateral portal, the femoral insertion is debrided with a shaver which is inserted through a deep anteromedial portal. Care is taken to ensure that the tibial ACL remnant remains largely intact.
A special drill guide is used via the deep anteromedial portal to place a 2.5 mm guide wire in the center of the ACL insertion. For femoral tunnel preparation via the anteromedial portal, the knee should be in flexion of >110°.
The position of the resulting hole is checked by switching the scope to the anteromedial portal. Landmarks for the femoral ACL insertion are the intercondylar line and the cartilage-bony junction as described previously. 6
If the guidewire entry point is deemed correct, the guidewire is reinserted and overdrilled with a 4.5 mm drill bit. The length of the tunnel is then determined. Tunnel lengths between 30 and 45 mm indicate an anatomical tunnel position. A blind tunnel is then widened to a length of approximately 30 mm with drills and dilators until the final tunnel diameter is reached. The use of dilators is recommended because drills can damage the tunnel wall.
The final tunnel is checked with the scope in the anteromedial portal.
After drilling the femoral tunnel, the tibial tunnel is created. A typical landmark for the center of the tibial ACL insertion is the anterior horn of the lateral meniscus.
To place a guide wire in the center of the tibial ACL insertion a tibial aiming device is brought into the joint via the medial portal.
For the tibial entry of the guide wire, a small 2-cm-long incision medial of the tibial tuberosity is needed. A knee flexion angle of 45° allows a good visualization of the ACL footprint.
After correct placement, the guide wire is overdrilled with a 6 mm drill. Then the tibial tunnel is gradually widened with drills and dilators until the final diameter of the graft is reached. The use of dilators is also advantageous on the tibial side. First, tunnel wall compaction can increase the stability of interference screw fixation and second, dilators damage the remnant of the ACL less than drills.
The remnant is then slightly thinned out from the inside with a shaver to reduce the risk of notch impingement. After tunnel preparation, an eyelet wire with a suture loop is passed into the femoral tunnel and the suture loop is pulled out of the tibial tunnel with a suture grasping forceps. With this suture loop, the graft is pulled into the joint. In order to facilitate the insertion of the graft, the thread can be deflected with the probe hook.
The bone block is pulled into the femoral tunnel with the white thread until it gets stuck in the tunnel. For femoral press fit fixation, the bone block is then splinted in the femoral tunnel with a mallet and pestle until the blue marking on the graft has just disappeared. The strength of the press-fit fixation is checked by maximum manual traction on the graft.
For tibial interference screw fixation, a thin nitinol wire is placed between the graft and the wall of the tibial tunnel to guide a biodegradable interference screw between the graft and the tunnel wall. Optionally, an additional tibial suspensory fixation can be added with a tibial button. With the tibial fixation, the remnant-sparing ACL reconstruction with the autologous QT bone graft is finished.
Potential complications and their corresponding prevention techniques include the following: infection that can be prevented by presoaking the graft in vancomycin, 3 cartilage damage at the medial femoral condyle due to the drill bit that can be prevented by correct medial portal placement, 6 posterior blow out of the femoral tunnel (consider femoral suspensory fixation), tunnel malplacement that can be prevented if you are familiar with anatomic landmarks and if you are uncertain, check the tunnel position with the fluoroscope. 6
For postoperative rehabilitation, a 3-phase and criteria-based rehabilitation protocol is recommended. Phase 1 focuses on controlling inflammation and pain. Patients use crutches with partial weight bearing and perform isometric exercises. Criteria for progression are range of motion (ROM) extension/flexion (E/F) 0-0-90, safe walking with partial weight bearing, decreasing pain, and decreasing effusion. Measures in phase 2 are weight bearing as tolerated, closed chain exercises, open kinetic chain exercises within the safe zone, and easy balance exercises. Goals for the transition to phase 3 are ROM E/F 0-0-120, safe walking with full weight bearing, decreasing pain, decreasing effusion, and pain free exertion of exercises. Measures of phase 3 are open kinetic chain exercises, jump training, and complex balance exercises. Criteria to qualify for a return to sports test are full range of motion, pain free running, no effusion, and pain free exertion of exercises.
Return to sport is allowed when the patient successfully completes a functional test battery. This test battery consists of basic criteria such as passive stability, ROM and absence of effusion and functional tests such as strength measurement, jumps tests, proprioception tests, and movement assessment. 1
Regarding patient outcomes there are 2 studies which examined the exact surgical technique which is presented in this video article.2,5 One study was published about the use of QT bone graft in primary ACL reconstruction and the other study focused on the results of revision ACL reconstruction.2,5 In both studies, there was no significant difference regarding the assessment of postoperative patient reported outcome measures such as Lysholm score and Knee Osteoarthritis Outcome Score (KOOS) and instrumental knee laxity measurement (KT 1000) between patients treated with autologous QT and hamstring grafts.
From these studies we conclude that the use of the QT bone graft is a good alternative to the use of hamstring grafts especially in patients where the hamstring tendons should be preserved. Examples are young high risk athletes who need the agonistic hamstrings to protect the graft and patients with 3° medial instability since a recent study has shown that the hamstrings are active medial stabilizers. 4
Footnotes
Submitted May 12, 2022; accepted July 21, 2022.
The authors declared that they have no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.