{"id":77,"date":"2008-02-13T14:04:54","date_gmt":"2008-02-13T14:04:54","guid":{"rendered":""},"modified":"2020-06-02T16:16:34","modified_gmt":"2020-06-02T21:16:34","slug":"surgical-reconstruction-of-the-anterior-cruciate-ligament-the-central-quadriceps-tendon-as-an-alternative-graft-source","status":"publish","type":"post","link":"https:\/\/thesportjournal.org\/article\/surgical-reconstruction-of-the-anterior-cruciate-ligament-the-central-quadriceps-tendon-as-an-alternative-graft-source\/","title":{"rendered":"Surgical Reconstruction of the Anterior Cruciate Ligament: The Central Quadriceps Tendon as an Alternative Graft Source"},"content":{"rendered":"
Submitted by: Albert W. Pearsall, IV, MD<\/div>\n

*Red numbers
\nindicate references<\/span><\/p>\n

INTRODUCTION<\/strong>
\nSignificant advances in surgical reconstruction of the anterior
\ncruciate ligament (ACL) have been made since Jones’ described
\nopen reconstruction with the central one-third patellar tendon
\nin 1963.29 Advancements in technology, arthroscopic instrumentation,
\nand surgical skills have decreased surgical morbidity while improving
\nfunctional outcome.5,
\n23<\/span> Continued technological
\nand surgical improvements in the 1990’s eventually enabled surgeons
\nto perform ACL reconstructions endoscopically. SIZE=”-2″>3, 4, 19, 23, 24, 37<\/p>\n

During the evolution of ACL reconstruction surgery, numerous
\ngraft sources have been described. Currently, the most commonly
\nutilized tissues for ACL reconstruction are autologous semitendinous\/gracilis
\ntendons (ST-G), central one-third patellar tendon (B-PT-B), and
\nallograft patellar tendon. >13, 14, 21, 22, 31, 32, 46, 49, 50
\nEach of these grafts has been touted
\nto reliably restore knee stability, thereby enabling many patients
\nto return to pre-injury activity levels. Despite these reports,
\ncomplications have been noted with all three types of tendons,
\nthe most frequent being anterior knee pain. SIZE=”-2″>1, 6, 7, 9, 10, 12, 17, 18<\/p>\n

Based upon its proven efficacy,
\nthe central 1\/3 autologous patellar tendon is considered by a
\nlarge number of orthopaedic surgeons to be the graft of choice
\nin the symptomatic ACL-deficient patient. However, the incidence
\nof anterior knee pain with the use of this graft has been reported
\nfrom 13% to 47%, which diminishes the functional outcome in a
\nlarge percentage of individuals. SIZE=”-2″>1, 35, 43-45, 51 Moreover, due to technical factors such as tunnel
\nangle and graft length, many B-PT-B grafts cannot be secured
\nat the joint level, resulting in non-anatomic graft fixation.
\nIn an effort to eliminate these problems, other graft sources
\nhave been explored. The ideal ACL graft should result in minimal
\nor no damage to the patient’s tissues after harvest. It should
\nenable immediate rigid fixation and reproduce the normal anatomy
\nof the native ACL. It should also restore normal proprioception
\nand kinematics to the knee. Although numerous graft sources have
\nbeen reported, currently, no graft material, autograft or allograft,
\ncan meet all these requirements.<\/p>\n

In an effort to minimize post-surgical
\nanterior knee pain after ACL reconstruction, the use of semitendinosus\/gracilis
\ntendons has been reported. Advocates of ST-G (hamstrings) point
\nout that post-operative patellar pain is diminished by virtue
\nof the patellar mechanism not being violated during graft harvest.
\nVarious authors have reported the incidence of anterior pain
\nto vary from 3% to 21% following hamstrings ACL reconstruction.<FONT
\nCOLOR=”#ff0000″ SIZE=”-2″>2, 11, 15, 26, 30,
\n33, 42 However, in the
\nauthor’s experience, the use of hamstrings for ACL reconstruction
\ndoes not eliminate anterior knee pain in many patients. In addition,
\nsome authors have reported increased tibial translation in females
\nafter ST-G ACL reconstruction. >16<\/p>\n

Allograft B-PT-B has been advocated
\nas an alternative graft source due to the lack of harvest morbidity
\nand decreased operative time required. SIZE=”-2″>25, 32, 36, 41, 46 However, despite the diminished risk of disease
\ntransmission, opponents of allografts cite reports of prolonged
\ngraft-tunnel healing and intraarticular reactions to some allografts.<FONT
\nCOLOR=”#ff0000″ SIZE=”-2″>28, 40<\/p>\n

As a result of the continued
\ncontroversy regarding the correct ACL graft source, an alternative
\ngraft has emerged, the central quadriceps tendon (CQT). The central
\nquadriceps tendon was reported as a graft source as early as
\n1979 by Marshall et al, however, it did not gain popularity among
\nsurgeons until the 1980’s and 1990’s. SIZE=”-2″> 8, 21, 34, 47 Proponents of the CQT cite it’s greater cross-sectional
\narea, lower strain at failure, and lower modulus of elasticity
\nwhen compared to patellar tendon. SIZE=”-2″>48
\nAdvocates have also cited the lower incidence of patellofemoral
\nsymptoms after CQT graft usage. >20, 31
\nOur experience at the University of South Alabama Medical Center
\nis similar, with less then 5% of patients demonstrating postoperative
\nanterior knee pain symptoms after CQT ACL reconstruction.<\/p>\n

The CQT consists of a central
\nportion of the quadriceps tendon approximately 10-11mm wide.
\nThe graft depth extends 7mm with an average length of approximately
\n80-90mm. When the graft is harvested as the initial portion of
\nthe surgical procedure, the central portion is obtained without
\nviolation of the suprapatellar pouch or transection of the quadriceps
\ntendon. This eliminates the need to repair the pouch or tendon
\nbefore proceeding with the arthroscopic portion of the procedure.<\/p>\n

Initial descriptions of the use of the CQT described harvest
\nof the tendon without a bone block from the patella.31 Prior
\nto the development of bioabsorable screws for soft tissue fixation,
\nsuch a graft would have required the tendon ends had to be secured
\nby sutures tied over a post, such a staple, button, or screw.
\nSeveral biomechanical studies have demonstrated that such fixation
\ndoes not reconstitute the normal isometricity of the ACL, with
\nincreased instability noted as the tibial side is fixed further
\naway from the articular surface. SIZE=”-2″>27, 38
\nConsequently, many authors now advocate graft fixation near the
\narticular surface insertions of the native ACL. SIZE=”-2″>39
\nWhen the CQT is being contemplated as a graft source, articular
\nfixation can be accomplished by harvesting a patellar bone block
\nand fixing both ends of the graft with bioabsorbable screws near
\nthe surface of the tibia and femur.<\/p>\n

SURGICAL TECHNIQUE<\/strong>
\nAfter previous studies (radiographs, MRI) and clinical examination
\nconfirm that the ACL is disrupted and causing symptomatic instability,
\nthe patient is brought to the operating room for reconstruction.
\nThe CQT is harvested through a short 2-3 inch incision obliquely
\nalong the lines of the quadriceps mechanism. After delineation
\nof the quadriceps tendon, a 10mm x 7mm x 85mm graft is harvested,
\nbeing careful to not violate the suprapatellar pouch. At the
\ndistal end of the quadriceps tendon a 10mm x 25mm x 8mm bone
\nplug is harvested from the proximal end of the patella. The patellar
\ndefect can be later filled with cancelleous bone from the tibial
\nreamings or with allograft chips. The CQT is sized on a back
\ntable to fit through the smallest tunnel that the tendon (not
\nthe bone) will glide through easily; the bone plug is trimmed
\nto fit accordingly. This usually represents 9-10mm. Two #2 Ethibond
\nsutures are placed in the patellar bone plug, while two #1 Ethibond
\nsutures are whipped stitched in the tendon end.<\/p>\n

After the stitches are in place
\nand CQT has been sized, appropriate markings are made to aid
\nthe surgeon during arthroscopic reconstruction. In our use of
\nthe CQT, we place the tendon side in the femoral tunnel, with
\nthe patellar bone block in the tibia. First, a pen mark is made
\nat the bone-tendon junction. Next, a distance of 35mm is measured
\nfrom the CQT-bone junction. This marked area represents the approximate
\nintraarticular distance of the native ACL. This distance is approximately
\n30mm in most individuals, however, we allocate an additional
\n5mm in case the graft slides more proximally in the femoral tunnel.
\nThe distance of the remaining tendon represents the portion of
\nthe tendon that will be pulled into the femoral tunnel (~25mm).
\nThe following calculation is what we use in preparing the CQT
\ngraft for implantation:
\n85mm<\/strong> {total graft} – 60mm<\/strong> {bone plug + intraarticular
\ntendon} = 25mm<\/strong> {femoral tunnel}
\nThe graft is set in a moist sponge until later implantation.<\/p>\n

After harvest of the CQT, a
\nroutine knee arthroscopy is performed. We routinely perform a
\n5-7mm lateral notchplasty, along with debridement or repair of
\nany meniscal lesions. Using a standard tibial guide set at an
\nangle of 55o, we drill a 9mm tibial tunnel centered 5mm anterior
\nto the PCL within the footprint of the native ACL. After the
\nposterior portion of the tibial tunnel has been debrided of all
\nsoft tissue and rasped posteriorly, a 7mm offset endoscopic guide
\nis placed through the tibial tunnel at the “10:30”
\nor “1:30” positions on the posterior femoral notch.
\nA 9-10mm femoral tunnel is reamed to the depth of the previous
\ncalculations (~ 25mm).<\/p>\n

After reaming, an eyed Beath
\npin (Arthrex, Naples, FL) is placed in the femoral tunnel. Sequential
\nimpaction dilatation of the tibial and femoral bone tunnels is
\nperformed to increase the bone density of the tunnels for bioabsorable
\nscrew placement. After the tunnels are dilated to the size of
\nthe graft (9-10mm), the tendon side of the CQT is brought into
\nthe femoral tunnel. Through the anteromedial or an accessory
\nanterior portal, a bioabsorable screw of the same diameter as
\nthe femoral tunnel is placed anterior to the graft. Fixation
\nof the graft is assessed by pulling upon the tibial sutures,while
\nthe knee is put through a range of motion. Tensioning the graft
\nthrough several motion cycles diminishes creep within the graft
\nprior to tibial fixation. After the graft is assessed in extension
\nfor signs of impingement, the knee is placed in 10o-20o of flexion
\nwith 5kg of tension place upon the tibial sutures. The graft
\nis fixed adjacent to the tibial articular surface with a 10mm
\nbioabsorable interference screw. The knee is assessed for anterior
\ntibial translation and the wounds closed with absorbable sutures.
\nPrior to waking the patient, an intraarticular pain pump is placed
\nwithin the knee.<\/p>\n

CLINICAL EXPERIENCE<\/strong>
\nAt the University of South Alabama Medical Center, our experience
\nwith CQT spans over 2 years, with nearly 20 cases. To date we
\nare gathering 2 year follow-up data. 1 patient ruptured his graft
\nduring athletics (collegiate athlete) at 9 months postoperatively.
\nNo patient has reported significant patellofemoral pain and there
\nhave been no ruptures of the quadriceps tendon. All patients
\nhave been happy with their results, indicating that they believe
\nthe procedure improved their quality of life.<\/p>\n

Other authors have reported
\ngood results with the CQT. Fulkerson reported excellent results
\nwith the use of the CQT with either endobutton or bioabsorbable
\nscrew fixation.20,
\n31<\/span> Leitman et al reported
\non 65 CQT graft cases with a KT-1000 side to side differences
\nof 2.1mm at 1-2 year follow-up. The authors noted that no patient
\nhad patellofemoral pain and all subjects had returned to their
\nprevious level of activity with no instances of quadriceps tendon
\nrupture.31 <\/span><\/p>\n

CONCLUSIONS<\/strong>
\nIndividuals with a disrupted anterior cruciate ligament and symptomatic
\nknee instability often require surgical reconstruction of the
\nACL. Over the last several decades, tremendous technological
\nadvances have enabled surgeons to reconstruct the ACL with a
\nmore anatomic and durable graft, while minimizing postoperative
\nmorbidity. As the evolution of ACL graft material continues,
\nnumerous graft choices are available. The central quadriceps
\ntendon (CQT) is an alternative graft source with biomechanical
\nproperties comparable to or better than a bone-patellar tendon-bone
\nor double-looped hamstrings graft. In early follow-up studies,
\npatients undergoing CQT ACL reconstruction have demonstrated
\nminimal patellofemoral symptoms and excellent clinical function.
\nThe CQT provides another weapon in the orthopaedic surgeon’s
\nrepertoire of surgical graft alternatives to reconstruct the
\nsymptomatic ACL-deficient knee.<\/p>\n

REFERENCES<\/strong><\/p>\n

    \n
  1. \n
      \n
    1. Aglietti P, Buzzi R, D’Andria
      \nS, et al. Patellofemoral problems after intraarticular anterior
      \ncruciate ligament reconstruction. Clin Orthop 1993;228:195.<\/li>\n
    2. Aglietti P, Buzzi R, Zaccherotti
      \nG, et al. Patella tendon versus doubled semitendinosus and gracilis
      \ntendons for anterior cruciate ligament reconstruction. Am J Sports
      \nMed 1994;22:211.<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n