Outcome of repeat revision of anterior cruciate ligament reconstruction is excellent or good in 70% of the cases, at an average 3 years follow up, although decreased after the second revision, in relation to the occurrence of meniscal tears and articular cartilage lesions. Meniscal and articular cartilage lesions are more frequent and more severe with recurrent laxity. The cause of failures is mainly recurrent trauma, followed by surgical technical errors.
ACL Rupture And Meniscus Repair Strategies
My own study aims to determine the incidence of meniscal tears and describe the tear morphology and selected treatment in patients undergoing anterior cruciate ligament (ACL) reconstruction. I will also discuss the potential market for future tissue engineering aimed at preserving meniscal function. A monocenter cohort of hundreds patients undergoing ACL reconstruction between January 1984 and December 2009 is evaluated. Data on patient demographics, presence of a meniscus tear at time of ACL reconstruction, tear morphology, and meniscal treatment are collected prospectively.
Meniscal tears
They are categorized into 3 potential tissue engineering treatment strategies: all-biologic repair, advanced repair, and scaffold replacement.
Of the knees, more than one out of 3 has medial meniscal tears and less than one out of two has lateral meniscal tears. Longitudinal tears are the most common tear morphology. The most frequent treatment method is partial meniscectomy at the time of ACL reconstruction : dozens od cases. Thirty percent of medial meniscal tears and 10% of lateral meniscal tears are eligible for all-biologic repair; 35% of medial meniscal tears and 35% of lateral meniscal tears are eligible for an advanced repair technique; and 35% of medial meniscal tears and 55% of lateral meniscal tears are eligible for scaffold replacement.
Meniscal preservation
Although meniscal preservation is generally accepted in the treatment of meniscal tears, most tears in my own cohort, as well as elsewhere published, are not repairable, despite contemporary methods.
The results of my cohort will hopefully stimulate and focus future research and development of new tissue engineering strategies for meniscus repair.
Meniscal repair is a successful procedure in conjunction with anterior cruciate ligament reconstruction. When confronted with a “repairable” meniscal tear at the time of anterior cruciate ligament reconstruction, orthopaedic surgeons can expect an estimated >90% “clinical success” rate at 2-year follow-up using a variety of methods as shown at least in one study.
ACL References
- Biau DJ, Katsahian S, Nizard R. Hamstring tendon autograft better than bone-patellar tendon-bone autograft in ACL reconstruction – a cumulative meta-analysis and clinically relevant sensitivity analysis applied to a previously published analysis. Acta Orthop. 2007;78(5):705-707.
- Chhabra A, Starman JS, Ferretti M, et al. Anatomic, radiographic, biomechanical, and kinematic evaluation of the anterior cruciate ligament and its two functional bundles. J Bone Joint Surg Am. 2006;88(Suppl 4):2-10.
- Colombet P, Robinson J, Jambou S, et al. Two-bundle, four-tunnel anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc. 2006;14(7):629-636. Epub 2005 Dec 9.
- Fithian DC, Paxton EW, Stone ML, et al. Prospective trial of a treatment algorithm for the management of the anterior cruciate ligament-injured knee. Am J Sports Med. 2005;33(3):335-346.
- Kurosaka,M Yoshiya S, Mizuno T, Mizuno K. Spontaneous healing of a tear of the anterior cruciate ligament. A report of two cases. J Bone Joint Surg (Am). 1998;80(8):1200-1203.
- Muneta T, Koga H, Morito T, et al. A retrospective study of the midterm outcome of two-bundle anterior cruciate ligament reconstruction using quadrupled semitendinosus tendon in comparison with one-bundle reconstruction. Arthroscopy. 2006;22(3):252-258.
- Yagi M, Kuroda R, Nagamune K, et al. Double-bundle ACL reconstruction can improve rotational stability. Clin Orthop Relat Res. 2007;454:100-107.
- Zantop T, Haase AK, Fu FH, Petersen W. Potential risk of cartilage damage in double bundle ACL reconstruction: impact of knee flexion angle and portal location on the femoral PL bundle tunnel. Arch Orthop Trauma Surg. Epub 2007 Dec 4
“Anatomic” Two-bundle ACL Reconstruction : A Concept
Anatomic two-bundle ACL reconstruction is worthy of our consideration, but one must remember that this is still a concept and not a proven entity. The proponents of the double-bundle concept make good sense anatomically.
Level 1 and 2 outcome studies show a reduction in the magnitude of the postoperative pivot shift (measurement of rotational stability) but no difference in clinical outcomes and return to sports and physical activity.
It is too early in 2008 to tell whether or not, this concept will reduce the arthritic changes we see after anterior cruciate ligament reconstruction.
As a result of this initiative, I do not change the “anatomic” position of the femoral drill hole for a single-bundle reconstruction from the classic 11 o’clock right knee: 1 o’clock left knee positions,, but keep my usual positions : a 9:30 right and 2:30 left knee. My drill hole uses to straddle the two recommended double-bundle drill holes, for a long time, since I start “modern” ACL reconstruction in 1984.
I feel a single-bundle reconstruction, properly placed anatomically, functions as does the double- bundle reconstruction with different fibers in the single-bundle experiencing stresses through the range of motion in the weightbearing knees, similar to the double bundle.
The single-bundle technique is certainly less demanding.
Time and level 1 and 2 studies will prove the double-bundle initiative to be right or wrong.
Study Design For Improvement Of Outcome For ACL Reconstructions
In expert hands, the double bundle reconstruction technique should show significant clinically relevant improvements in randomized controlled trials and/or prospective cohorts with minimum validated patient-reported outcome measures.
If everyone performs well, this should be duplicated by a multi-center group of individuals in both academic and private practice in a prospective longitudinal cohort.
“Average” Orthopedic Surgeon and Double-bundle Reconstruction
Some colleague calls the “average orthopedic surgeon”, one who does 10 to 15 ACL reconstructions a year : should this ”average” surgeon switch to the double-bundle reconstruction?
In Fu‘s opinion, whether someone switches to doing double-bundle ACL reconstructions depends on the individual surgeon and their dedication to learning new techniques and principles. With the correct training and application of the double-bundle concept all orthopedic surgeons should be able to stay current and provide the best care for their patients, whether it be with single-bundle or double-bundle ACL surgery.
Howell, as I do, does not think a surgeon who does 100 to 200 per year should switch. If a surgeon is having difficulty preventing the pivot shift, then we would suggest he first refines his surgical technique to eliminate PCL and roof impingement before considering the double bundle.
In Kurosaka’s opinion, also, learning single-bundle reconstruction with drill holes created in the true anatomic center of insertion is very important and basic. In most of the cases, good results can be expected by this technique. Following Kurosaka, however, I would recommend that surgeons, like me, who does 40 to 50 cases a year think about doing anatomic double-bundle reconstruction. I believe that two anatomic bundles, when indicated, would behave better than a single-bundle reconstruction.
Spindler’s opinion is that as we are not even sure what the minimum number of single-bundle reconstructions per year is to have reproducible outcomes and as the double bundle is a more complicated technique, we, the average surgeon, should not switch.
Double-bundle Initiative Changes My Thinking About ACL Reconstruction
Many animals, including the monkey shown on the left, have three bundles of ACL, the anteromedial bundle, intermediate bundle, and posterolateral bundle. They also have more prominent bony landmarks on the ACL femoral insertion site (middle) that suggests the existence of different ACL bundles and their higher demand for ACL function. Some animals, such as the gorilla specimen on the right, have larger medial to lateral condyle ratios, suggesting their need for greater knee rotation.
Images: Fu FH
ACL reconstruction advances tremendously over my over 40-year career, progressing from open ACL useless direct repair to open reconstruction and arthroscopic techniques. Surgical techniques are still in 2010 mainly focused on ways to improve the ability to arthroscopically reconstruct the ACL. However, in the early 1990s the literature and I show that 30% to 40% of patients are still having knee symptoms or are unable to return fully to their activities after ACL reconstruction.
These suboptimal outcomes leads to a more anatomical approach to ACL reconstruction – among which, the development of the double-bundle concept.
Four things have changed my practice and approach to ACL surgery.
The first is anatomy.
The first is anatomy, because anatomical studies using fetal and cadaveric specimens proven that the ACL is composed of two functional bundles with different sizes and tensioning patterns. Traditional techniques fail to restore the anatomy of the ACL and therefore normal knee kinematics.
The second is… anatomy.
Second is the discovery that the insertion sites are dynamic and change orientation with knee motion. The ACL insertion site on the femur is vertical in extension with the AM bundle being on top/proximal to the PL bundle. This orientation changes with knee flexion as the ACL insertion site becomes more horizontal as the AM bundle moves posterior and becomes less proximal to the PL bundle. Chhabra et al in 2006 show that the AM and PL bundles move from being parallel in extension to a crossed position in flexion. This consideration is critical, since historically the femoral insertion site of the ACL has been defined at 0° but most ACL knee surgery is performed from 45° to 90° of knee flexion.
The third is… anatomy.
The third influence is biomechanical and robotic studies. Results from these studies underscore the double-bundle technique’s ability to more closely restore native knee kinematics than single-bundle techniques.
The fourth is… anatomy.
My truely early recognition that transtibial drilling leads to nonanatomic femoral tunnel placement has still a dramatic impact on my approach. Transtibial tunnel drilling is the most common approach to ACL surgery in North America and elsewhere (France, etc.), but as it requires moving the tibial tunnel posteriorly towards PL bundle location to avoid graft impingement, it very often causes a high femoral AM tunnel location leading to graft mismatch and a nonanatomic reconstruction.
Sagittal plane MRI showing the two-bundle anatomy of an intact ACL (left). A non-anatomic single-bundle reconstruction showing a vertically placed graft from tibial PL to high femoral AM position is shown (right). This 10 year follow-up MRI shows no graft impingement and good biologic healing. But the mismatched tunnel placement has lead to insufficient rotational stability with a symptomatic pivot shift.
Images: Fu FH
Clinical Outcome Measures Use To Evaluate Single- Vs. Double-bundle Reconstruction
Short-term
Clinically relevant outcomes to compare single- vs. double-bundle, or for that matter any bundle, should include in the short-term, a reproducible operation with minimum major complications that significantly improves
- general quality of life,
- sports-specific quality of life, and
- measure of knee quality of life.
An example would be SF-36 (IKDC, MARX Activity, KOOS Sports and Recreation), KOOS Knee quality of life or Lysholm.
Return to sports participation
Next, we would have to look at return to sports participation and whether the patients maintain or increase activity level through either Marx or Tegner.
Then we should evaluate structural parameters like stability in AP with a Lachman and/or KT, and “rotational” via a pivot shift or undefined PE test, and standing X-ray for joint space.
Finally some functional measurement such as HOP test or neuromuscular performance measure should be used.
Long-term
In the long-term, avoid graft failures, do not do complicated revisions and reduce the risk of osteo arthritis.
Revision Of Failed Single-bundle Reconstruction To Double-bundle Reconstruction
Owing to Kurosaka and to me, difficulty depends where the original drill hole is created.
- If it is created in the center of the ACL insertion, it may be very difficult to revise to double-bundle reconstruction.
- However, in the majority of my revision cases, mostly “traditional arthroscopic ACL reconstructions”, the femoral drill hole is created anteriorly and proximally in a nonanatomic location, thus creating two new anatomic drill holes would be relatively easy. In the tibia, most of traditional drill holes were created posteriorly in the PL insertion site, therefore; I either enlarge the original drill hole anteriorly or create a new drill hole in the AM-bundle insertion site.
Thus, there would be usually two revision drill holes in the femur and one in the tibia.
AM Or PL bundle, Isolated Reconstruction
- In about 10% of my cases, instability is relatively mild and one of the bundles has continuity with the anatomic attachment preserved.
- In these cases we could do single-bundle reconstruction (Kurosaka), and the remnant AM or PL bundle might be left unattached.
- I assume that remnant tissue may also remodel along with healing process of the implanted graft.
