Editorial Commentary: Gait Symmetry After Anterior Cruciate Ligament Reconstruction Is Improved Using Functional Rehabilitation Braces That Resist Knee Motion

The effort of the rehabilitation journey to solve the several known functional and clinical problems after anterior cruciate ligament reconstruction should be directed toward implementing effective recovery strategies starting the day after surgery. Resistance training is a reliable approach to restore general knee function, but in the early postoperative stages, it may be difficult to apply proper loading strategies to obtain tangible improvements owing to surgery-related impairments. Accordingly, applying continuous light resistance during functional tasks such as gait may help to address this issue. As such, bracing models that provide resistance to knee motion have recently been developed and have been shown to help in restoring a proper walking pattern in terms of moment and range-of-motion symmetry. Therefore, the adoption of such bracing models may be regarded as a suitable option to consider to boost the achievement of rehabilitative milestones, therefore generally improving rehabilitation quality.     

Editorial Commentary: Pursue the Anatomy of the Knee Anterior Cruciate Ligament Footprint

The paradigm of anterior cruciate ligament reconstruction has shifted from nonanatomic/isometric to anatomic reconstruction so as to mimic the native anterior cruciate ligament anatomy, as well as its function. A triple-bundle reconstruction technique more precisely mimics the native anterior cruciate ligament. On the other hand, functional advantages of triple-bundle reconstruction have not been fully elucidated. Comparative clinical studies between reconstruction techniques are needed.     

Editorial Commentary: The Anterior Cruciate Ligament Is a Dynamic Structure

The anterior cruciate ligament (ACL) is a dynamic structure composed of distinct bundles that function synergistically to facilitate normal knee kinematics in concert with bony morphology. Characterized by individual uniqueness, the ACL is inherently subject to both anatomic and morphological variations as well as physiologic aging. No locus on the lateral wall of the intercondylar notch is truly isometric through full range of motion, suggesting the ACL is a dynamic structure. Future studies should explore dynamic ACL behavior in vivo.     

Editorial Commentary: The Quest to Prevent Knee Anterior Cruciate Ligament Bone Tunnel Widening Continues

The exploration of methods to improve healing of a tendon graft in a bone tunnel in anterior cruciate ligament reconstruction has been a subject of basic and translational research for over 30 years. It is well recognized that the graft attachment site to the bone represents the “weak link” in the early healing period. We as clinicians search for methods to augment healing of the tendon graft in the bone tunnel. Agents and techniques that improve osteoinduction may improve healing. Implanted chondrocytes may promote tendon-to-bone healing by participating in new bone formation or, alternatively, by providing signaling molecules that stimulate local or distant endogenous cells. Tracking of cell fate after implantation will be required to further delineate biologic mechanisms.     

Editorial Commentary: Anterior Cruciate Ligament Costs Are Surprising

Given increasing health care costs and clinical equipoise on numerous topics, value calculations are critical. Cost-minimization analysis evaluates throughout a single episode of care. For anterior cruciate ligament reconstruction, this is a reasonable approach given that cost-effectiveness data have been published. Using Healthcare Cost and Utilization Project data, general anesthesia, anesthesia time, greater age, and medical comorbidities were correlated with higher costs. Among the surprising results were increased costs with male gender and Hispanic race. Interestingly, the location of the surgery, surgery center versus hospital, or meniscal repair did not significantly impact costs. This information can be used by physicians for cost comparison and factors that determine costs.     

Editorial Commentary: Hybrids Make for Good Cars but Probably Not Anterior Cruciate Ligament Grafts

Use of allograft/autograft hybrid hamstring anterior cruciate ligament grafts has gained popularity as a method to ensure appropriate graft diameter when autograft alone is insufficient. Several institutional series have been published with conflicting results. When there is any concern for autograft hamstring diameter, it is potentially better to consider other graft options. Patellar tendon autograft remains an excellent graft option for many patients. In patients where a soft-tissue graft is desired, including adolescents, quadriceps tendon has emerged as a promising option with excellent clinical outcomes. Even in patients in which hamstrings are used as a graft, when insufficient diameter is encountered, newer techniques, including the use of retrograde reamers, allows for creation of a bulleted graft of sufficient diameter without the need for allograft augmentation. We have completely abandoned the use of hybrid grafts in this younger population at our institution for these reasons. Because there are numerous other options available for anterior cruciate ligament reconstruction in patients where hamstring size may be a concern, this may become less of a debate over the next decade.     

Editorial Commentary: No Difference in Knee Osteoarthritis After Single-Bundle Versus Double-Bundle Anterior Cruciate Ligament Reconstruction

Systematic reviews now play a key role in evidence-based medicine, summarizing empirical findings from evaluated studies on a specific problem and examining the variability of those. These reviews help scientists integrate and evaluate relevant information in their research and support practitioners in decision-making processes. Since the early years of the current century, there has been a debate as to whether double-bundle or single-bundle reconstruction of the anterior cruciate ligament will better protect the knee. An essential aspect in the general indication of ligament reconstruction of the knee joint is the aim to prevent or at least to slow down the development process of osteoarthritis. At present, most clinical measures show no difference in outcome between single-bundle and double-bundle anterior cruciate ligament reconstruction. Systematic review of the literature investigating development of knee osteoarthritis after single-bundle and double-bundle anterior cruciate ligament reconstruction also shows no difference in outcome for this very important measure.     

Editorial Commentary: Return to Play Following Revision Anterior Cruciate Ligament Reconstruction

In many cases, athletes return to play after anterior cruciate ligament (ACL) reconstruction. In such cases, after a second ACL tear, these athletes may again expert full return to play after ACL revision. Unfortunately, results after revision ACL reconstruction are inferior to results after primary surgery. Sport specific data is difficult to determine, as are predictors of positive outcomes which include concomitant pathology or psychological factors. Chances of return to the same level may be 60% or less.     

Editorial Commentary: Osseous Anatomy of the Knee in Female Patients is a Significant Risk Factor for Anterior Cruciate Ligament Injury and Anterior Cruciate Ligament Graft Failure

Risk for anterior cruciate ligament (ACL) injury is greater in female than in male patients for a myriad of reasons, with osseous anatomy about the knee proving to be one significant risk factor for ACL injury and/or ACL graft failure. While femoral intercondylar notch size/shape and posterior tibial slope have been well-examined in this regard for their contribution to potential ACL injury, morphology of the lateral femoral condyle is a newer entity that may be linked to risk for ACL injury. Smaller/stenotic femoral intercondylar notches, increased posterior tibial slope of the lateral tibial plateau, and increased posterior condylar depth of the lateral femoral condyle have all been shown to increase risk for ACL injury and/or ACL graft failure. Such associations provide knee surgeons with food for thought when considering procedures such as notchplasty, staged anterior closing wedge high tibial osteotomy, and anterolateral ligament reconstruction/augmentation at the time of primary or revision ACL reconstruction. Further investigation into the links between pre-operative imaging parameters and outcomes following such concomitant procedures is required in order for any significant conclusions to be drawn.     

Editorial Commentary: Combined Anterior Cruciate Ligament Reconstruction and Medial Meniscal Transplantation Improve Functional Outcomes When Properly Indicated

The anterior cruciate ligament (ACL) and medial meniscus both contribute to anteroposterior translation of the tibia. Biomechanical studies have found increased translation at both 30° and 90° when transecting the posterior horn of the medial meniscus, and clinically, medial meniscal deficiency has been shown to have a 46% increase in ACL graft strain at 90°. Medial meniscal deficiency is a risk factor for failure after ACL reconstruction, with a hazard ratio of 15.1. The combination of meniscal allograft transplantation and ACL reconstruction is technically demanding but results in mid- to long-term clinical improvement in well-indicated patients. Patients with medial meniscal deficiency and failed ACL reconstruction or with ACL deficiency and medial-sided knee pain due to meniscal deficiency are candidates for combined procedures. On the basis of our experience, acute meniscal injury is not an indication for primary meniscal transplantation in any setting. Surgeons should repair the meniscus if reparable or perform partial meniscectomy and see how the patient responds. There is insufficient evidence to show that early meniscal transplantation will be chondroprotective. We reserve this procedure for the indications previously described. Severe osteoarthritis (Kellgren-Lawrence grades III and IV) and Outerbridge grade IV focal chondral defects of the tibiofemoral compartment that are not amenable to cartilage repair are absolute contraindications to the combined procedure.     

Editorial Commentary: Revision Anterior Cruciate Ligament Using Soft Tissue Autograft Quadriceps Is Effective but Not Recommended for All Comers

The average revision rate is between 3.2% and 11.1%following primary anterior cruciate ligament (ACL) reconstructions,¹ and an objective failure rate of 13.7% has been reported for revision ACLR.² Prior implants, positioning of tunnels, and muscle weakness from the prior reconstruction present challenges. Additionally, graft choice for the revision reconstruction is restricted, depending on the primary reconstruction. Revision ACL reconstruction with the all-soft tissue quadriceps tendon autograft is a viable option with 83.3% of the patients surpassing the minimally clinically significant difference for International Knee Documentation Committee (IKDC) scores, which is similar to outcomes for revision ACL reconstruction (ACLR) using bone-patella-bone and hamstring tendon autografts. Furthermore, objective strength data suggest that it is possible to achieve equal limb symmetry index strength ratios even in the setting of prior bone-patella tendon-bone autograft. However, although I am cautiously optimistic regarding soft tissue quadriceps autograft in revision ACLR, I would be hesitant to recommend it for all comers. In my experience, young high school/collegiate female athletes with primary reconstruction using BPTB autograft may not be able to tolerate a secondary insult to the extensor mechanism via quadriceps tendon (QT) autograft harvest, where hematoma and arthrofibrosis could be concerns. Furthermore, increased posterior tibial slope may require evaluation and treatment, and the addition of a lateral extra-articular tenodesis may reduce residual rotatory laxity in ACL revision patients.     

Editorial Commentary: Revision of Failed Double-Bundle Anterior Cruciate Ligament Reconstruction

Double-bundle (DB) reconstruction of the anterior cruciate ligament was favored for several years. However, recent studies increasingly show that this technique does not provide a clear advantage over the less-invasive single-bundle technique. Unfortunately, the graft fails relatively often after ACL reconstruction. Postoperative communication of the bone tunnels through bone tunnel widening is possible. Since 2 drill channels are created in the DB technique, femoral as well as tibial, it is assumed that this technique may cause problems during revision. So, in part, revision may require a 2-step procedure with bone graft filling of the tunnels as the first step. It is important that surgeons with experience using DB publish their revision strategies and experiences.     

Editorial Commentary: Lateral Extra-Articular Tenodesis Reduces Anterior Cruciate Ligament Graft Rerupture Rates: Proper Anterior Cruciate Ligament and Lateral Extra-Articular Tenodesis Technique Is Vital to Prevent Complications

Lateral extra-articular tenodesis (LET) reduces anterior cruciate ligament (ACL) graft rerupture rates in high-risk patients. I believe in ilio-tibial band (ITB)-related LET to restrain anterolateral rotatory instability (ALRI) in ACL that is injured and reconstructed, and not in the “anterolateral ligament” or related techniques. However, the potential for conflict of a modified Lemaire LET femoral tunnel with an ACL femoral tunnel is higher than appreciated, and it risks iatrogenic ACL graft damage or compromised fixation. For MacIntosh LET, I use a staple to fix a strip of ITB (left attached distally to Gerdy’s tubercle) at the lateral femoral metaphysis. The tines of the staple are proximal to the ACL femoral tunnel and fixation, so conflict cannot occur. For modified Lemaire LET, the ITB graft is (taken deep to the LCL and) attached at “Lemaire’s point” on the lateral femur (proximal and posterior to the LCL femoral attachment). For fixation, I use a 15-mm length suture anchor, sufficiently short to avoid conflict. I presume fixation is less strong with sutures, so the 2-3 cm of ITB graft proximal to the suture are turned distally back over the LCL and sutured to itself. This does create a thickened contour to the lateral knee, but excellent clinical outcomes. Finally, I recommend the anteromedial bundle (AMB) position for the femoral tunnel, as in my experience in professional soccer players, using the central “anatomic” position increases rates of ACL graft rerupture. Moreover, “anatomic” femoral tunnel position results in a flatter trajectory increasing the risk of conflict with a LET tunnel (or lateral physical damage in patients with open growth plates).     

Editorial Commentary: The Anterior Cruciate Ligament May Be Safer Wearing a Suture Tape Augmentation Seat Belt: Click It or Ticket

Bone-patellar tendon-bone autograft for anterior cruciate ligament (ACL) reconstruction has the most data to support its use. However, there may still be room for improvement, and younger age, insufficient rehabilitation, altered neuromuscular patterns, and precocious return to play can increase risk of graft failure. High strength suture augmentation of soft-tissue repair or reconstruction has gained traction in a variety of applications for the knee, including medial collateral and posteromedial corner, lateral collateral ligament, posterior cruciate ligament, and ACL. For ACL reconstruction, the technique consists of using either suture or suture tape fixed at the femoral and tibial ACL footprints to allow for independent tensioning to back up the separately tensioned ACL reconstruction. The static augment serves as a load-sharing device, allowing the graft to see more strain during earlier levels of graft strain, until graft elongation occurs to a critical level whereby the augment will experience more strain than the graft. Hence, the “seat belt” analogy. This is distinct from static augmentation, where the high strength suture is fixed to the graft. Static augmentation (without tensioning separately from the graft) results in a load-sharing device and increased stiffness, but potential stress shielding compared with the “seat belt.” If suture tape augmentation improves patient outcome, it is a worthwhile to “click it.”