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The arthroscopic “impingement test” during anterior cruciate ligament reconstruction
Arthroscopy: The Journal of Arthroscopic and Related Surgery 9(6):714-717
Published by Raven Press, Ltd. © 1993 ArthroscopyAssociationof North America
Technical Note
The Arthroscopic "Impingement Test" During Anterior Cruciate Ligament Reconstruction Darren L. Johnson, M.D., Mark D. Miller, M.D., Major USAF MC, and Freddie H. Fu, M.D.
Summary: A primary goal of A C L reconstruction is to avoid graft impingement, which may lead to loss of motion and/or an increased incidence of instability. Although surgeons are cognizant of this potential problem, the intraoperative correction of graft impingement is technically demanding because the graft-notch relationship is obscured by the trochlea articulating with the tibial plateau during the final 10° of extension. We present a simple impingement test that is performed before graft insertion and fixation to help avoid this potential pitfall. Key Words: Anterior cruciate ligament reconstruction---Graft i m p i n g e m e n t - - N o t c h p l a s t y - - N o t c h stenosis.
Intraarticular anterior cruciate ligament (ACL) reconstruction is now accepted as the treatment of choice in a young active individual with a functionally unstable ACL-deficient knee. One of the potential complications after intraarticular reconstruction is graft impingement within the intercondylar notch (1). Impingement can result in ligament attrition with recurrent patholaxity or capture of the knee with restricted range of motion (2-4). In order to avoid graft impingement, a notchplasty is usually recommended (5). The amount of notchplasty (extent of bone to be removed) is often patient specific, based on a number of variables to be considered: presence of joint hyperelasticity (genu recurvatum), unique notch architecture, placement of osseous tunnels, and size of the graft to be placed (6-8). A nonanatomically
positioned tunnel should not be corrected with an excessive notchplasty. Although one can verify intraoperatively that there is no graft impingement, postoperative notch regrowth of up to I cm may occur, resulting in graft abrasion and late graft rupture. In an effort to determine the exact amount of bone to be removed during endoscopic ACL reconstruction before graft placement, the senior author (F.H.F.) has developed a simple technique using a commercially available bone tunnel expander (Fig. 1) (Instrument Makar, Inc., Okemos, MI).
From the Section of Sports Medicine, Division of Orthopaedic Surgery, University of Kentucky, Lexington, Kentucky (D.L.J.); Department of Orthopaedic Surgery, U.S. Air Force Academy, Colorado Springs, Colorado (M.D.M.); and Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania (F.H.F.), U.S.A. Address correspondence and reprint requests to Dr. Freddie H. Fu, Center for Sports Medicine and Rehabilitation, Baum Blvd at Craig, Pittsburgh, PA 15213, U.S.A.
FIG. 1. Variable sized bone tunnel expanders (Instrument Makar, Inc., Okemos, MI).
7/4
ARTHROSCOPIC IMPINGEMENT TEST
FIG. 2. Arthroscopic view of bone tunnel expander in position at the intraarticular opening of the femoral tunnel.
SURGICAL TECHNIQUE The technique of single-incision endoscopic ACL reconstruction has been well described previously (9,10). Successful reconstruction using this tech-
715
nique requires the ability of the surgeon to anatomically place the intraarticular portion of the tibial tunnel within the posteromedial "footprint" of the native ACL insertion. The extraarticular portion must exit midway between the apex of the tibial tubercle and the posteromedial border of the tibia (11). An error in tunnel placement should not be corrected with an excessive notchplasty because this will only lead to surgical failure. The femoral tunnel is placed using endoscopic techniques, leaving a 1- to 2-mm posterior cortical shell. At this point, the impingement test can be performed. An appropriately sized bone tunnel expander equal to the prepared graft size is placed within the intercondylar notch via the tibial tunnel. Do not insert the expander into the femoral tunnel. Place the tip of the device at the intraarticular opening of the femoral tunnel (Fig. 2). Under direct arthroscopic visualization the knee is taken through a complete range of motion while checking for bony impingement sites upon the device (Fig. 3). Potential areas of bony impingement include the medial wall of the lateral femoral condyle, superior roof of the inter-
FIG. 3. Arthroscopic view of the Impingement Test at different degrees of knee flexion. Arthroscopy, Vol, 9, No. 6, 1993
716
D. L. J O H N S O N E T A L .
FIG. 4. Arthroscopic view after graft insertion and fixation verifying no bony impingement at all flexion angles.
condylar notch, and tibial spines. Using a variety of arthroscopic instruments, the notchplasty is fine tuned to the exact dimensions of the bone tunnel expander. Performance of this impingement test confirms that impingement has been eliminated before graft placement. This will ensure that once the graft is inserted and secured, there will be no need for further notchplasty, thereby avoiding iatrogenic graft injury. After graft insertion and fixation, the knee is again taken through a complete range of motion to verify the accuracy of this simple test (Fig. 4). DISCUSSION An adequately performed notchplasty is a requirement for success of intraarticular ACL reconstruction (1,2,8). Removing excessive bone may lead to articular incongruence between the patellofemoral or tibiofemoral articulation. It has also been shown that an excessive notchplasty at the femoral anatomic attachment site of the ACL may disrupt the normal isometry of the ACL replacement subArthroscopy, Vol. 9, No. 6, 1993
stitute (12). Failure to remove enough bone will lead to graft impingement with resultant ligament failure and/or loss of motion. In performing this simple impingement test described herein, the surgeon is able to fine tune the notchplasty before graft placement. We have found this technique to be an extremely valuable addition to our ACL reconstruction technique, especially in revision cases after failed primary intraarticular reconstruction. Removal of an excessive amount of bone is relatively easy to do in revision cases because of the absence of normal arthroscopic anatomical landmarks. By using this technique, only the necessary amount of bone is removed. Variable sized tunnel expanders may be used depending on the size of the graft required for each specific case. REFERENCES 1. Graft B, Uhr F. Complications ofintra-articular anterior cruciate ligament reconstruction. Clin Sports M e d 1988;17i83548. 2. Howell SM, Clark JA. Tibial tunnel placement in anterior cruciate ligament reconstructions and graft impingement. Clin Orthop 1992;283:187-95.
ARTHROSCOPIC
3. Harrier CD, Irrgang J J, Paul JJ, et al. Loss of motion after anterior cruciate ligament reconstruction. Am J Sports Med 1992;20:499-506. 4. Romano VM, Graf BK, Keene JS, Lange RH. Anterior cruciate ligament reconstruction; the effect of tibial tunnel placement on range of motion. Am J Sports Med 1993;21: 415-8. 5. Hardin GT, Bach BR, Bush-Joseph CA, et al. Endoscopic single-incision anterior cruciate ligament reconstruction using pateUar tendon autograft. A m J Knee Surg 1992;5:14455. 6. Anderson AF, Lipscomb AB, Lindahl KJ, et al. Analysis of the intercondylar notch by computed tomography. A m J Sports Med 1987;15:547-52. 7. Howell SM, Clark JA, Farley TE. A rationale for predicting anterior cruciate graft impingement by the intercondylar roof. A m J Sports Med 1991;19:276-82.
IMPINGEMENT
TEST
717
8. Yaru NC, Daniel DM, Penner O. The effect of tibial attachment site on graft impingement in an anterior cruciate ligament reconstruction. A m J Sports Med 1992;20:217-20. 9. Christian CA, Indelicato PA. Allograft anterior cruciate ligament reconstruction with patellar tendon: an endoscopic technique. Op Techniques Sports Med 1993;1:50-7. 10. Beck CL, P~mlos LE, Rosenberg TD. Anterior cruciate ligament reconstruction with endoscopic technique. Op Techniques Orthop 1992;2:86-98. 11. Olson EJ, Fu FH, Harrier CD, et al. Towards optimal fibial tunnel placement in endoscopic anterior cruciate ligament reconstruction. Poster Exhibit A57, American Academy of Orthopaedic Surgeons, San Francisco, CA, 1993. 12. Penner DA, Daniel DM, Wood P, et al. An in vitro study of anterior cruciate ligament graft placement and isometry. A m J Sports Med 1988;16:238-43.
Arthroscopy, Vol. 9, No. 6, 1993
Published by Raven Press, Ltd. © 1993 ArthroscopyAssociationof North America
Technical Note
The Arthroscopic "Impingement Test" During Anterior Cruciate Ligament Reconstruction Darren L. Johnson, M.D., Mark D. Miller, M.D., Major USAF MC, and Freddie H. Fu, M.D.
Summary: A primary goal of A C L reconstruction is to avoid graft impingement, which may lead to loss of motion and/or an increased incidence of instability. Although surgeons are cognizant of this potential problem, the intraoperative correction of graft impingement is technically demanding because the graft-notch relationship is obscured by the trochlea articulating with the tibial plateau during the final 10° of extension. We present a simple impingement test that is performed before graft insertion and fixation to help avoid this potential pitfall. Key Words: Anterior cruciate ligament reconstruction---Graft i m p i n g e m e n t - - N o t c h p l a s t y - - N o t c h stenosis.
Intraarticular anterior cruciate ligament (ACL) reconstruction is now accepted as the treatment of choice in a young active individual with a functionally unstable ACL-deficient knee. One of the potential complications after intraarticular reconstruction is graft impingement within the intercondylar notch (1). Impingement can result in ligament attrition with recurrent patholaxity or capture of the knee with restricted range of motion (2-4). In order to avoid graft impingement, a notchplasty is usually recommended (5). The amount of notchplasty (extent of bone to be removed) is often patient specific, based on a number of variables to be considered: presence of joint hyperelasticity (genu recurvatum), unique notch architecture, placement of osseous tunnels, and size of the graft to be placed (6-8). A nonanatomically
positioned tunnel should not be corrected with an excessive notchplasty. Although one can verify intraoperatively that there is no graft impingement, postoperative notch regrowth of up to I cm may occur, resulting in graft abrasion and late graft rupture. In an effort to determine the exact amount of bone to be removed during endoscopic ACL reconstruction before graft placement, the senior author (F.H.F.) has developed a simple technique using a commercially available bone tunnel expander (Fig. 1) (Instrument Makar, Inc., Okemos, MI).
From the Section of Sports Medicine, Division of Orthopaedic Surgery, University of Kentucky, Lexington, Kentucky (D.L.J.); Department of Orthopaedic Surgery, U.S. Air Force Academy, Colorado Springs, Colorado (M.D.M.); and Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania (F.H.F.), U.S.A. Address correspondence and reprint requests to Dr. Freddie H. Fu, Center for Sports Medicine and Rehabilitation, Baum Blvd at Craig, Pittsburgh, PA 15213, U.S.A.
FIG. 1. Variable sized bone tunnel expanders (Instrument Makar, Inc., Okemos, MI).
7/4
ARTHROSCOPIC IMPINGEMENT TEST
FIG. 2. Arthroscopic view of bone tunnel expander in position at the intraarticular opening of the femoral tunnel.
SURGICAL TECHNIQUE The technique of single-incision endoscopic ACL reconstruction has been well described previously (9,10). Successful reconstruction using this tech-
715
nique requires the ability of the surgeon to anatomically place the intraarticular portion of the tibial tunnel within the posteromedial "footprint" of the native ACL insertion. The extraarticular portion must exit midway between the apex of the tibial tubercle and the posteromedial border of the tibia (11). An error in tunnel placement should not be corrected with an excessive notchplasty because this will only lead to surgical failure. The femoral tunnel is placed using endoscopic techniques, leaving a 1- to 2-mm posterior cortical shell. At this point, the impingement test can be performed. An appropriately sized bone tunnel expander equal to the prepared graft size is placed within the intercondylar notch via the tibial tunnel. Do not insert the expander into the femoral tunnel. Place the tip of the device at the intraarticular opening of the femoral tunnel (Fig. 2). Under direct arthroscopic visualization the knee is taken through a complete range of motion while checking for bony impingement sites upon the device (Fig. 3). Potential areas of bony impingement include the medial wall of the lateral femoral condyle, superior roof of the inter-
FIG. 3. Arthroscopic view of the Impingement Test at different degrees of knee flexion. Arthroscopy, Vol, 9, No. 6, 1993
716
D. L. J O H N S O N E T A L .
FIG. 4. Arthroscopic view after graft insertion and fixation verifying no bony impingement at all flexion angles.
condylar notch, and tibial spines. Using a variety of arthroscopic instruments, the notchplasty is fine tuned to the exact dimensions of the bone tunnel expander. Performance of this impingement test confirms that impingement has been eliminated before graft placement. This will ensure that once the graft is inserted and secured, there will be no need for further notchplasty, thereby avoiding iatrogenic graft injury. After graft insertion and fixation, the knee is again taken through a complete range of motion to verify the accuracy of this simple test (Fig. 4). DISCUSSION An adequately performed notchplasty is a requirement for success of intraarticular ACL reconstruction (1,2,8). Removing excessive bone may lead to articular incongruence between the patellofemoral or tibiofemoral articulation. It has also been shown that an excessive notchplasty at the femoral anatomic attachment site of the ACL may disrupt the normal isometry of the ACL replacement subArthroscopy, Vol. 9, No. 6, 1993
stitute (12). Failure to remove enough bone will lead to graft impingement with resultant ligament failure and/or loss of motion. In performing this simple impingement test described herein, the surgeon is able to fine tune the notchplasty before graft placement. We have found this technique to be an extremely valuable addition to our ACL reconstruction technique, especially in revision cases after failed primary intraarticular reconstruction. Removal of an excessive amount of bone is relatively easy to do in revision cases because of the absence of normal arthroscopic anatomical landmarks. By using this technique, only the necessary amount of bone is removed. Variable sized tunnel expanders may be used depending on the size of the graft required for each specific case. REFERENCES 1. Graft B, Uhr F. Complications ofintra-articular anterior cruciate ligament reconstruction. Clin Sports M e d 1988;17i83548. 2. Howell SM, Clark JA. Tibial tunnel placement in anterior cruciate ligament reconstructions and graft impingement. Clin Orthop 1992;283:187-95.
ARTHROSCOPIC
3. Harrier CD, Irrgang J J, Paul JJ, et al. Loss of motion after anterior cruciate ligament reconstruction. Am J Sports Med 1992;20:499-506. 4. Romano VM, Graf BK, Keene JS, Lange RH. Anterior cruciate ligament reconstruction; the effect of tibial tunnel placement on range of motion. Am J Sports Med 1993;21: 415-8. 5. Hardin GT, Bach BR, Bush-Joseph CA, et al. Endoscopic single-incision anterior cruciate ligament reconstruction using pateUar tendon autograft. A m J Knee Surg 1992;5:14455. 6. Anderson AF, Lipscomb AB, Lindahl KJ, et al. Analysis of the intercondylar notch by computed tomography. A m J Sports Med 1987;15:547-52. 7. Howell SM, Clark JA, Farley TE. A rationale for predicting anterior cruciate graft impingement by the intercondylar roof. A m J Sports Med 1991;19:276-82.
IMPINGEMENT
TEST
717
8. Yaru NC, Daniel DM, Penner O. The effect of tibial attachment site on graft impingement in an anterior cruciate ligament reconstruction. A m J Sports Med 1992;20:217-20. 9. Christian CA, Indelicato PA. Allograft anterior cruciate ligament reconstruction with patellar tendon: an endoscopic technique. Op Techniques Sports Med 1993;1:50-7. 10. Beck CL, P~mlos LE, Rosenberg TD. Anterior cruciate ligament reconstruction with endoscopic technique. Op Techniques Orthop 1992;2:86-98. 11. Olson EJ, Fu FH, Harrier CD, et al. Towards optimal fibial tunnel placement in endoscopic anterior cruciate ligament reconstruction. Poster Exhibit A57, American Academy of Orthopaedic Surgeons, San Francisco, CA, 1993. 12. Penner DA, Daniel DM, Wood P, et al. An in vitro study of anterior cruciate ligament graft placement and isometry. A m J Sports Med 1988;16:238-43.
Arthroscopy, Vol. 9, No. 6, 1993