Editorial Commentary: Respect the Posterior Tibial Slope and Make Slope-Reducing Osteotomies an Integral Part of the Surgical Repertoire

The posterior tibial slope (PTS), as part of the complex 3-dimensional bony knee morphology, has been a topic of interest for many years but has recently become a hot topic in the scope of reconstructive knee ligament surgery. Biomechanical and clinical evidence suggests that the PTS is an independent and well-accepted risk factor for primary and recurrent anterior cruciate ligament (ACL) injuries. As part of an individualized approach to anatomic ACL reconstruction, the PTS should be respected, and if necessary, addressed, which is especially true for the treatment of multiple failed ACL reconstructions.     

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: During Anterior Cruciate Ligament Reconstruction,Lateral Extra-Articular Procedures Have Risks and Should be Reserved for Proper Indications: Do Not LET ALL Revision Anterior Cruciate Ligament Reconstructions Be the Same

Recently, there has been renewed interest in performing a lateral extra-articular procedure (LEAP), either an anterolateral ligament (ALL) reconstruction or a LET (lateral extra-articular tenodesis) to address a deficiency of the anterolateral complex (ALC) of the knee during anterior cruciate ligament (ACL) reconstruction. The ALC consists of the superficial and deep aspects of the iliotibial band with its Kaplan fiber attachments on the distal femur, along with the ALL, a structure within the anterolateral capsule. The ALC functions to provide anterolateral rotatory stability as a secondary stabilizer of the ACL. The evidence to date is that the addition of a LEAP to a revision ACL reconstruction may reduce the risk of repeat graft failure and rotatory laxity. However, in some cases, performing a LEAP may not confer any additional benefit and add unwarranted risk including lateral pain, reduced quadriceps strength, longer time to recovery, and overconstraint of the lateral compartment with associated cartilage damage. Perhaps LEAP is best indicated for high-risk patients (young, active in pivoting sports, high-grade pivot-shift, generalized ligamentous laxity or knee hyperextension, Segond fracture, chronic ACL lesion, lateral femoral notch sign, lateral coronal plane laxity, concurrent meniscus repair, or ALC injury on magnetic resonance imaging). Other modifiable risk factors should not be ignored (graft choice, graft size, tunnel position, graft fixation, associated injuries such as a lateral meniscal root tear, or anatomic factors such as an increased posterior tibial slope). Do not LET ALL revision anterior cruciate ligament reconstructions be the same! A lateral extra-articular procedure may sometimes, but not always, reduce the risk of further failure.     

Patient-Related Risk Factors for Contralateral Anterior Cruciate Ligament (ACL) Tear After ACL Reconstruction: An Analysis of 3707 Primary ACL Reconstructions

Background

Return to play after anterior cruciate ligament (ACL) reconstruction can increase risk for both ipsilateral graft rupture and contralateral ACL rupture. The risk for injury of the contralateral knee after ACL reconstruction could be nearly double that of ipsilateral graft rupture.

Questions/Purposes

We sought to identify independent, patient-related risk factors for contralateral ACL rupture following primary ACL reconstruction.

Methods

A national database was queried for patients who underwent primary ACL reconstruction from 2007 to 2015 with a minimum of 2 years of post-operative follow-up (n = 12,044). Patients who underwent subsequent primary ACL reconstruction on the contralateral extremity were then identified. A multivariate binomial logistic regression analysis was utilized to evaluate patient-related risk factors for contralateral ACL rupture, including demographic and comorbidity variables. Adjusted odds ratios and 95% confidence intervals were calculated for each risk factor.

Results

Of the 3707 patients who had a minimum of 2 years of database activity and comprised the study group, 204 (5.5%) experienced a contralateral ACL rupture requiring reconstruction. Independent risk factors for contralateral ACL rupture included age less than 20 years, female gender, tobacco use, and depression. Obesity, morbid obesity, type 1 diabetes, type 2 diabetes, and a history of anxiety were not significant predictors of contralateral injury.

Conclusion

We were able to adequately power an analysis to identify several significant patient-related risk factors for contralateral ACL rupture after primary ACL reconstruction, including younger age, female gender, tobacco use, and depression. This information can be used to counsel patients on the risk of injury to the contralateral knee.

     

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: Anterior Cruciate Ligament Reconstruction Alone Is Not Sufficient in Anterolateral Complex Injury: Extra-Articular Augmentation (Lateral Extra-Articular Tenodesis [LET] or Anterolateral Ligament [ALL] Reconstruction) Allows Surgeons to Indicate Tight (LET) or Just Right (ALL) on a Case-by-Case Basis

Extra-articular augmentation has become an essential consideration in contemporary anterior cruciate ligament reconstruction (ACL) surgery. The verdict is still out on the extra-articular augmentation procedure of choice to accompany ACL surgery in the treatment of anterolateral rotatory instability. Anterolateral ligament reconstruction and lateral extra-articular tenodesis) are 2 common methods with clinical outcome data to support their use. Both procedures have demonstrated clinical effectiveness in reducing the rate of recurrent ACL tear/recurrent knee instability. Biomechanics studies to date have reached varied conclusions; however, a growing body of research including the study discussed here suggests both procedures enhance stability in the setting of surgical treatment of anterolateral rotatory instability, whereas ACL reconstruction alone is not sufficient in the setting of anterolateral complex injury. I suggest surgeons carefully consider when to augment ACL surgery with an extra-articular procedure and feel there is a place for both procedures. When extra constraint is indicated, I recommend lateral extra-articular tenodesis. When patient athletic demands may be lesser and a less-invasive procedure is indicated, anterolateral ligament augmentation of ACL reconstruction is my preference.     

Editorial Commentary: Outcomes After Anterior Cruciate Ligament Reconstruction Are Defined by Individual Anatomy,Including Both Soft Tissue and Bone Morphology: It’s All Important

Well-designed studies add to our understanding of the anatomy, biology, biomechanics, and outcomes of the anterior cruciate ligament (ACL) following injury. Despite improvements in ACL treatment, we are still unable to exactly restore the individually unique function of the native ACL due to the complexity of knee physiology. The ACL is a dynamic structure with a rich neurovascular supply, distinct bundles, and 3-dimensional architecture that function in synergy with the bony morphology to facilitate healthy knee kinematics. Furthermore, the ACL exhibits a wide range of natural, anatomic variation. Since anatomic ACL reconstruction has been defined as functional restoration of the ACL to its native dimensions and collagen orientation, in addition to restoring the native footprint, it is important to restore the native size of the ACL, as the size of the tibial insertion site can vary by a factor of 3 from patient to patient. Moreover, variations in ACL soft tissue reflect differences in bony morphology. Bony morphology influences the static and dynamic biomechanics of the knee. Several bony morphologic factors influence the outcomes following ACL reconstruction, including posterior tibial slope, femoral condylar offset ratio, and notch shape. Morphologic differences that reflect pathologic states, such as the lateral notch sign and posterolateral plateau fracture, have been shown to be associated with greater grade instability. To respect the unique nature of each patient during surgical treatment, it is necessary to perform an individualized, anatomic, and value-based ACL reconstruction.     

Allograft anterior cruciate ligament reconstruction: indications, techniques, and outcomes

The anterior cruciate ligament (ACL) is an important stabilizer of the knee against translational and rotational forces. The goal of anatomic reconstruction of the ACL-deficient knee is to re-create a stable knee that will allow for return to sport and prevent recurrent injury. Multiple graft options exist for ACL reconstruction, and each option has unique advantages and disadvantages. With appropriate patient selection, each graft can be utilized to optimize patient outcomes. Allograft options limit morbidity following ACL reconstruction, but care must be taken with surgical technique and postoperative rehabilitation to allow for graft incorporation. An understanding of the surgical technique and differences between graft options will allow the patient, surgeon, and physical therapist to maximize outcomes following ACL reconstruction.     

Single Femoral Socket Double-Bundle Anterior Cruciate Ligament Reconstruction Using Tibialis Anterior Tendon: Description of a New Technique

The native anterior cruciate ligament (ACL) has been shown to consist of 2 functional bundles with independent behavior throughout range of knee motion. Conventional arthroscopic ACL reconstruction techniques selectively recreate the anteromedial bundle of the native ACL only. Numerous studies have reported the failure to restore normal knee kinematics in an ACL-deficient knee using a single-bundle reconstruction. It has been suggested that by reconstructing both the anteromedial and posterolateral bundles of the ACL, more normal knee kinematics may be achieved. Several authors have described surgical techniques to recreate the 2 functional bundles and they range from using 2 femoral tunnels to using a single femoral tunnel with the other bundle passed over the top. This article describes a new technique of recreating the 2 functional bundles of the ACL with tibialis anterior tendon allograft using a single femoral socket.     

Editorial Commentary: Early Anterior Cruciate Ligament Reconstruction Decreases the Risk of Developing Irreparable Meniscus Tears in Female Athletes

There has been a substantial increase in the participation of women in sports since the passage of Title IX in 1972. With increased participation has come a rise in athletic injuries, including anterior cruciate ligament (ACL) tears. Numerous factors (modifiable and nonmodifiable) contribute to the 2 to 8 times increased risk of ACL tears in female compared with male athletes. The sports with the greatest risk of ACL injury include cutting sports such as soccer (1.1% per season), basketball (0.9% per season), volleyball, and lacrosse. In addition, female patients have a 33.7% greater risk of a subsequent contralateral ACL tear. Approximately 70% of ACL tears are the result of noncontact injuries. Numerous factors contribute to the increased risk of ACL tears in female athletes, including nonmodifiable (hormonal fluctuations, sex differences in knee geometry) and modifiable risk factors (neuromuscular control). Injury-prevention programs focus on modifiable risk factors and have been shown to be incredibly effective, decreasing the risk of ACL tears up to 50%. ACL tears commonly are associated with meniscus tears, including medial meniscus ramp and lateral posterior root lesions; therefore, thorough assessment is critical to identify this pathology. Early ACL reconstruction (i.e., <12 months following injury) increases the likelihood of being able to repair meniscus tears. Given the much greater risk of ACL tears and lower rate of return to sport in female athletes, this group warrants special attention to identify and treat these injuries earlier and subsequently improve overall outcomes.     

Recurrent surgical site infection after anterior cruciate ligament reconstruction: A case report

BACKGROUND Surgical site infections following anterior cruciate ligament(ACL) reconstruction are an uncommon but potentially devastating complication.In this study, we present an unusual case of recurrent infection of the knee after an ACL reconstruction, and discuss the importance of accurate diagnosis and appropriate management, including the issue of graft preservation versus removal.CASE SUMMARY A 33-year-old gentleman underwent ACL reconstruction using a hamstring tendon autograft with suspensory Endobutton fixation to the distal femur and an interference screw fixation to the proximal tibia.Four years after ACL reconstruction, he developed an abscess over the proximal tibia and underwent incision and drainage.Remnant suture material was found at the base of the abscess and was removed.Five years later, he re-presented with a lateral distal thigh abscess that encroached the femoral tunnel.He underwent incision and drainage of the abscess which was later complicated by a chronic discharging sinus.Repeated magnetic resonance imaging revealed a fistulous communication between the lateral thigh wound extending toward the femoral tunnel with suggestion of osteomyelitis.Decision was made for a second surgery and the patient was counselled about the need for graft removal should there be intraarticular involvement.Knee arthroscopy revealed the graft to be intact with no evidence of intra-articular involvement.As such, the decision was made to retain the ACL graft.Re-debridement, excision of the sinus tract and removal of Endobutton was also performed in the same setting.Joint fluid cultures did not grow bacteria.However, tissue cultures from the femoral tunnel abscess grew Enterobacter cloacae complex, similar to what grew in tissue cultures from the tibial abscess five years earlier.In view of the recurrent and indolent nature of the infection, antibiotic therapy was escalated from Clindamycin to Ertapenem.He completed a six-week course of intravenous antibiotics and has been well for six months since surgery, with excellent knee function and no evidence of any further infection.CONCLUSION Prompt and accurate diagnosis of surgical site infection following ACL reconstruction, including the exclusion of intra-articular involvement, is important for timely and appropriate treatment.Arthroscopic debridement and removal of implant with graft preservation, together with a course of antibiotics,is a suitable treatment option for extra-articular knee infections following ACL reconstruction.     

Editorial Commentary: Timing of the Combined Anterior Cruciate Ligament and Anterolateral Ligament Reconstruction: Still a Debatable Issue

Anterior cruciate ligament (ACL) injuries frequently occur as the results of twisting injury of the knee. Accompanying damages to other structures at the time of injury determine the severity of the injury, subsequent surgical procedures, and hence, clinical outcomes. Anterolateral ligament (ALL) seems to act as a side-bar of the ACL rather than a major ligament that should be reconstructed separately. We should also consider the pros and cons of the adding ALL reconstruction procedures. There is insufficient evidence that can either support or refute that ALL plays an important role for knee stability. Determining the timing of the combined reconstruction is still a debatable issue, just like the efficacy of combined ACL and ALL reconstruction.     

Controversies in soft-tissue anterior cruciate ligament reconstruction: grafts, bundles, tunnels, fixation, and harvest

Increased stability has been reported with both autografts and allografts for anterior cruciate ligament (ACL) reconstruction. However, meta-analysis has shown significantly lower overall knee stability rates and more than double the abnormal stability rate with allografts. Some issues surrounding allograft sterilization (ie, risk of disease transmission) are unresolved, and cost is also a concern. Single-bundle ACL reconstruction can produce high stability rates when tunnels are properly placed, but there is evidence that double-bundle repair may offer greater rotatory stability. Cortical fixation has been associated with increased stability owing to the high stiffness of cortical bone. Anterior and posterior approaches are both recommended. The controversy related to single-bundle versus double-bundle ACL reconstruction remains unresolved.     

The ligament augmentation device: an historical perspective.

Anterior cruciate ligament (ACL) injury is the most common ligament injury in the knee, and a significant number of patients may develop progressive instability and disability despite aggressive rehabilitation. Various materials have been used for its reconstruction. These include autografts, allografts, prosthetic ligaments, and synthetic augmentation of the biological tissue. The concept of ligament augmentation device (LAD) arose from the observation that biological grafts undergo a phase of degeneration and loss of strength before being incorporated. The LAD is meant to protect the biological graft during this vulnerable phase. However, it provokes an inflammatory reaction in the knee, and has been found to delay maturation of autogenous graft in humans. In experimental situations, the LAD has been found to share loads in a composite graft. It has also been found to be substantially stronger than the biological graft. However, in clinical situations no significant advantages have been observed with the use of LAD to augment patellar tendon or hamstring reconstruction of the chronic ACL-deficient knee or in the acute setting to augment repair of the torn ACL. There are very few reports of the use of LAD in reconstruction of the posterior cruciate ligament, and again these do not suggest any advantage in its use. Insertion of the LAD implies the introduction of a foreign material into the knee, has been associated with complications such as reactive synovitis and effusions, and may also be associated with an increased risk of infection. At present, there is no evidence that its routine use should be advocated in uncomplicated reconstructions of the ACL using biological grafts.     

Decreased quadriceps activation measured hours prior to a noncontact anterior cruciate ligament tear

STUDY DESIGN: Case report. BACKGROUND: Decreased quadriceps activation has been shown to be present following anterior cruciate ligament (ACL) injury, but its presence prior to ACL injury is unknown. The purpose of this case report was to describe the level of quadriceps activation measured hours before a noncontact ACL injury in an individual who previously demonstrated known biomechanical risk factors for ACL injury. CASE DESCRIPTION: A 23-year-old female (height, 176.9 cm; mass, 72.4 kg), sustained a left noncontact ACL injury while landing from a jump stop during a recreational basketball game. This case was unique because data regarding landing biomechanics and quadriceps force and activation were gathered in 2 separate, unrelated studies prior to injury. OUTCOMES: Peak external knee abduction moment (-65.3 Nm) during a drop jump landing 8 months prior to injury indicated elevated risk for ACL injury. Involved quadriceps central activation ratios (CAR) were obtained 1 week (CAR, 0.81) and 4 hours (CAR, 0.77) prior to injury. Strength and CAR (0.76) measurements changed very little within 36 hours of injury and both strength, and activation (CAR, 0.90) improved following surgical reconstruction and formal rehabilitation. DISCUSSION: An individual with known biomechanical risk factors for ACL injury may compound risk for noncontact ACL injury if decreased quadriceps activation is also present. LEVEL OF EVIDENCE: Prognosis, level 4.     

Editorial Commentary: Increased Tibial Slope Is Associated With Anterior Cruciate Ligament Injury Risk,and Tibial Slope Increases in the Skeletally Immature,Anterior Cruciate Ligament-Deficient Knee: A Chicken or Egg Causality Dilemma?

Increased tibial slope is associated with increased risk of anterior cruciate ligament (ACL) injury in the skeletally immature. Recent studies, however, emphasize a mutual influence, as tibial slope has been shown to increase over time in the ACL-deficient skeletally immature knee. It is hypothesized that altered biomechanics with enhanced posterior force transmission in the ACL-deficient knee may influence the developing physis, leading to altered longitudinal growth and increased tibial slope. In addition to tibial slope, the meniscal geometry, including meniscal bone angle and meniscal slope, have been shown to influence the risk of ACL injury. In the skeletally immature knee, especially, the soft tissue geometry is thought to have significant impact on ACL injury risk. However, it remains unknown whether alteration of the meniscal slope may represent a causality of ACL deficiency.     

Risk factors for anterior cruciate ligament injury: assessment of tibial plateau anatomic variables on conventional MRI using a new combined method

Purpose  

The purpose of this study was to assess, in anterior cruciate ligament (ACL)-injured and -uninjured population, tibial plateau anatomic variables [medial and lateral tibial plateau slopes (MTPS and LTPS) and medial tibial plateau depth (MTPD)] on conventional magnetic resonance imaging (MRI) using a novel combined method and to determine whether these variables are risk factors for ACL injury.     

Posterior Tibial Slope: Understand Bony Morphology to Protect Knee Cruciate Ligament Grafts

Improved understanding of the biomechanical significance and clinical repercussions of tibial slope on cruciate ligament function has sparked a newfound clinical interest in this morphological feature. Using either magnetic resonance imaging or lateral tibia radiographs, the anterior-posterior angulation of the tibial plateau relative to the tibial shaft can be measured. Clinical and biomechanical studies have reported that increased posterior tibial slope (PTS) places significantly increased tension on the native and reconstructed anterior cruciate ligament (ACL), leading to an increased risk of failure. It has also been suggested that increased PTS of the lateral tibial plateau has a greater impact on ACL forces and anterior tibial translation than PTS of the medial tibial plateau. Conversely, a decreased PTS has been shown to be a risk factor for recurvatum deformity, posterior cruciate ligament (PCL) injury, and posterior tibial translation and has been linked to single bundle PCL reconstruction failure. In the setting of ACL insufficiency with a PTS greater than 12°, anterior closing wedge osteotomy has been shown to be protective for ACL reconstructions. Alternatively, some surgeons have advocated for the addition of lateral extraarticular stabilization procedures in the setting of increased PTS. Further, in the setting of PCL insufficiency with an anteriorly directed, or flat, PTS, anterior opening wedge osteotomy has shown encouraging results. In addition, double bundle PCL reconstructions should be strongly considered in the setting of anteriorly directed, or flat, tibial slope.     

Pre-operative Static Anterior Tibial Translation Assessed on MRI Does Not Influence Return to Sport or Satisfaction After Anterior Cruciate Ligament Reconstruction

Background

It has been suggested that the degree of anterior tibial translation (ATT) as measured passively on imaging studies (static ATT) after an anterior cruciate ligament (ACL) injury may influence outcomes after ACL reconstruction. However, there is a lack of evidence supporting these suggestions.

Questions/Purposes

The purpose of this retrospective prognostic study was to assess the predictive value of pre-operative static ATT in knees with ACL injury on return to sport and in satisfaction after ACL reconstruction. Our hypothesis was that greater static ATT would be associated with lower rates of return to sport and lower levels of satisfaction.

Methods

Patients treated with ACL reconstruction were identified from an institutional registry and assigned to one of three groups according to their ACL injury type: acute ACL injury, chronic ACL injury, and failed ACL reconstruction. ATT in each knee compartment was measured using magnetic resonance imaging, and a retrospective telephone questionnaire was used to investigate post-ACL reconstruction return to sport and subjects’ satisfaction.

Results

One hundred thirty patients (52 acute with ACL injury, 29 with chronic ACL injury, and 49 with failed ACL reconstruction) completed the questionnaire, with a mean follow-up of 5.67 years. Ninety-seven patients (74.6%) returned to their primary sport, of whom 63 (65%) returned to the same level of sport. The mean time to return to sport was 10.1 months (range, 2 to 24 months). Overall, 113 patients (87%) were either very satisfied or satisfied with their outcomes. No difference in medial or lateral ATT was found between patients who returned to sport and those who did not. The failed-ACL reconstruction group had significantly lower rates of return to sport than did acutely and chronically injured patients (60.4% versus 88.5% and 75.9%, respectively).

Conclusion

The degree of pre-operative ATT in an ACL-deficient knee was not correlated with return to sport or satisfaction after ACL reconstruction. In this study cohort, only failed-ACL reconstruction patients undergoing revision ACL reconstruction were significantly less likely to return to their main sport. They were also less likely to return to sport at their pre-operative level, if they did return to sport.