Copyright © 2009 by The Journal of Bone and Joint Surgery, Inc.
Commentary & Perspective
Commentary & Perspective by
Armando Felipe Vidal, MD, and Eric C. McCarty, MD*,
University of Colorado Hospital, Denver, Colorado
Posted February 2009
Surgical techniques to address anterior cruciate
insufficiency have advanced considerably over the past few decades. Our current
endoscopic capabilities are far advanced from the techniques of direct repair
of the ligament or extra-articular reconstructions of decades past. These
advances have come with improvements in knee stability and patient outcomes. This
improvement is due largely to the ability of modern reconstructions to restore the
anatomy, kinematics, and function of the anterior cruciate ligament with
minimal morbidity. However, there is little question that, despite these
advances, there remains room for improvement.
The past few years have ushered in a potential new era in the
surgical management of the anterior cruciate ligament-deficient knee. The
concepts of double-bundle and anatomic anterior cruciate ligament reconstruction
have generated a substantial amount of interest in techniques that may further
improve knee stability and outcome. Biomechanical studies have demonstrated that
double-bundle techniques exhibit superior ability to control both translation
and coupled rotation in in vitro models1. The conundrum here is
whether or not these improved biomechanical properties will translate into
improved patient outcomes and, if so, at what price. As Dr. Harner has warned, "as
we create new techniques, we also may create new problems."2
The double-bundle technique is an excellent procedure. Several
Level-1 prospective randomized trials have demonstrated that the technique is
safe and effective in restoring knee stability and return to function and
athletics. However, it remains unclear if this technique represents a clinical
improvement over our current procedures3.
The literature on the subject can be difficult to interpret.
Authors differ in their techniques, tunnel position, number of tunnels, and
tensioning patterns for the bundles. Not all double bundles are created
equally. Additionally, we have discovered that our tools to "objectively"
examine anterior cruciate ligament laxity following reconstruction are probably
not sufficiently sophisticated to give us a true sense of the knee's function. Although
improved KT-2000 measurements, such as were demonstrated in this study, are
useful information—they may not be predictive of a patient's outcome4.
Assessment of coupled rotation is likely a better measure of success, but pivot-shift
testing is subjective and a cost-effective generalizable KT equivalent for the
pivot shift is not yet available.
We would caution the reader against the broad application of
these techniques to all patients undergoing reconstructive surgery for anterior
cruciate ligament deficiency. The majority of these procedures are being done
by high-volume anterior cruciate ligament surgeons. Many of them are at
academic centers with mature research infrastructures in place to follow these
patients and educate us on the pearls, pitfalls, and clinical utility of the
procedure. Several factors, including ideal indications, cost-effectiveness, and
the technical challenges of revision surgery, still remain to be fully
understood. At a time when there is little agreement among surgeons with regard
to ideal tunnel placement for single-bundle procedures, how do we expect to
fully understand what the best double-bundle technique is?
In summary, the double-bundle technique for anterior
cruciate ligament reconstruction is an innovative and potentially revolutionary
advance in the surgical management of the anterior cruciate ligament-deficient
knee. At this time, however, the literature does not support the widespread use
of these techniques for primary anterior cruciate ligament reconstruction. Continued
research into patient outcomes and improved objective assessment tools are
still necessary to better define the patient population that may benefit from
these techniques. As the authors of this paper implied, there is likely a group
of patients who are more cruciate dependent than others; single-bundle
techniques may be insufficient to control knee stability in these patient
populations. Attempting to define whether all patients, or just some, will
benefit from the biomechanical advantage of the double-bundle technique is an
important challenge going forward. Moreover, as financial concerns further
dictate the cost-effectiveness of our interventions, the question will arise as
to whether or not the increased operative time and implant expense are
justified. The ultimate goal is to achieve improved patient-oriented outcomes, not
just improved scores on "objective" measures of laxity. The next few years will
be very interesting as the rest of this story unfolds.
*The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity.
References
1. Yagi M, Wong EK, Kanamori A, Debski RE, Fu FH, Woo SL. Biomechanical analysis of an anatomic anterior cruciate ligament reconstruction. Am J Sports Med. 2002;30:660-6.
2. Harner CD, Poehling GG. Double bundle or double trouble? Arthroscopy. 2004;20:1013-4.
3. Meredick RB, Vance KJ, Appleby D, Lubowitz JH. Outcome of single-bundle versus double-bundle reconstruction of the anterior cruciate ligament: a meta-analysis. Am J Sports Med. 2008;36:1414-21.
4. Kocher MS, Steadman JR, Briggs KK, Sterett WI, Hawkins RJ. Relationships between objective assessment of ligament stability and subjective assessment of symptoms and function after anterior cruciate ligament reconstruction. Am J Sports Med. 2004;32:629-34.
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