Anterolateral Rotatory Instability Research Articles

Biomechanical Effects of Additional Anterolateral Structure Reconstruction With Different Femoral Attachment Sites on Anterior Cruciate Ligament Reconstruction

Background: Recently reported anterolateral structure reconstructions (ALSRs) to augment intra-articular anterior cruciate ligament reconstruction (ACLR) use various femoral attachment sites, and their biomechanical effects are still unknown. Hypothesis: ALSR concomitant with ACLR would control anterolateral rotational instability better than ACLR alone, and if ALSR had different femoral attachment sites, there would be different effects on its control of anterolateral rotational instability. Study Design: Controlled laboratory study. Methods: Twelve fresh-frozen hemipelvis lower limbs were included. Anterior tibial translation during the Lachman test and tibial acceleration during the pivot-shift test were measured with a 3-dimensional electromagnetic measurement system in situations with the (1) ACL and ALS intact, (2) ACL and ALS cut, (3) ALSR without ACLR (ALSR alone), (4) ACLR without ALSR (ACLR alone), and (5) ALSR with ACLR. Three femoral attachment sites were used for ALSR: F1, 2 mm anterior and 2 mm distal to the lateral epicondyle; F2, 4 mm posterior and 8 mm proximal to the lateral epicondyle; and F3, over-the-top position for the lateral extra-articular tenodesis. The Steel test and Wilcoxon signed rank test were used for statistical analysis. Results: Anterior tibial translation during the Lachman test in the ACL and ALS–cut state was significantly larger than it was in the ACL and ALS–intact state, while its difference disappeared after ACLR. As for the pivot-shift test, additional ALSR with F2 to ACLR significantly decreased the acceleration (P = .046), although additional ALSR with F1 and F3 showed no significant effect. Conclusion: ALSR with the femoral attachment site 4 mm posterior and 8 mm proximal to the lateral epicondyle in addition to ACLR played a role in reducing anterolateral rotational instability the most effectively among the measured attachment sites. Clinical Relevance: The present data will contribute to determine the appropriate femoral attachment site for ALSR to better control anterolateral rotational instability after ACL reconstruction.

The Kaplan Fibers of the Iliotibial Band Can Be Identified on Routine Knee Magnetic Resonance Imaging

Background: The Kaplan fibers (KFs) of the iliotibial band have been suggested to play a role in anterolateral rotational instability of the knee, particularly in the setting of an anterior cruciate ligament (ACL) rupture. Description of the normal magnetic resonance imaging (MRI) anatomy of the KFs may facilitate subsequent investigation into the MRI signs of injury. Purpose: To assess if the KF complex can be identified on 3-T MRI using standard knee protocols. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: 3-T MRI scans of 50 ACL-intact knees were reviewed independently by a musculoskeletal radiologist and 2 orthopaedic surgeons. Identification of the KFs was based on radiological diagnostic criteria developed a priori. Identification of the KFs in the sagittal, coronal, and axial planes was recorded. Interobserver reliability was assessed using the Kappa statistic. Detailed anatomy including distance to the joint line and relationship to adjacent structures was recorded. Results: The mean patient age was 43 years (range, 15-81 years), 58% were male, and 50% were right knees. The KFs were identified by at least 2 reviewers on the sagittal images in 96% of cases, on the axial images in 76% of cases, and on the coronal images in 4% of cases. The mean distance from the KF distal femoral insertion to the lateral joint line was 50.1 mm (SD, 6.6 mm) and the mean distance to the lateral gastrocnemius tendon origin was 10.8 mm (SD, 8.6 mm). The KFs were consistently identified immediately anterior to the superior lateral geniculate artery on sagittal imaging. Interobserver reliability for identification was best in the sagittal plane (Kappa 0.5) and worst in the coronal plane (Kappa 0.1). Conclusion: The KF complex can be identified on routine MRI sequences in the ACL-intact knee; however, there is low to moderate interobserver reliability. Imaging in the sagittal plane had the highest rate of identification and the coronal plane the lowest. There is a consistent relationship between the most distal KF femoral attachment and the lateral joint line, lateral gastrocnemius tendon, and superior lateral geniculate artery.

Radiographic Landmarks for Femoral Tunnel Positioning in Lateral Extra-articular Tenodesis Procedures

Background: Lateral extra-articular tenodesis (LET) is being increasingly performed as an additional procedure in both primary and revision anterior cruciate ligament reconstruction in patients with excessive anterolateral rotatory instability. Consistent guidelines for femoral tunnel placement would aid in intraoperative reproducible graft placement and postoperative evaluation of LET procedures. Purpose: To determine radiographic landmarks of a recently described isometric femoral attachment area in LET procedures with reference to consistent radiographic reference lines. Study Design: Descriptive laboratory study. Methods: Ten fresh-frozen cadaveric knees were dissected. The footprints of the lateral femoral epicondyle (LFE) apex and the deep aspects of the iliotibial tract, with its Kaplan fiber attachments (KFAs) on the distal femur, were marked with a 2.5-mm steel ball. True lateral radiographic images were taken. Mean absolute LFE and KFA distances were measured from the posterior cortex line (anterior-posterior direction) and from the perpendicular line intersecting the contact of the posterior femoral condyle (proximal-distal direction), respectively. Furthermore, positions were measured relative to the femur width. Finally, radiographic descriptions of an isometric femoral attachment area were developed. Results: The mean LFE and KFA positions were found to be 4 ± 4 mm posterior and 4 ± 3 mm anterior to the posterior cortex line, and 6 ± 4 mm distal and 20 ± 5 mm proximal to the perpendicular line intersecting the posterior femoral condyle, respectively. The mean LFE and KFA locations, relative to the femur width, were found at –12% and 11% (anterior-posterior) and –17% and 59% (proximal-distal), respectively. Femoral tunnel placement on or posterior to the femoral cortex line and proximal to the posterior femoral condyle within a 10-mm distance ensures that the tunnel remains safely located in the isometric zone. Conclusion: Radiographic landmarks for an isometric femoral tunnel placement in LET procedures were described. Clinical Relevance: These findings may help to intraoperatively guide surgeons for an accurate, reproducible femoral tunnel placement and to reduce the potential risk of tunnel misplacement, as well as to aid in the postoperative evaluation of LET procedures in patients with residual complaints.

Combined Anterior Cruciate Ligament Reconstruction and Lateral Extra-Articular Tenodesis

Anterolateral rotational instability may persist after anterior cruciate ligament (ACL) reconstruction for a variety of reasons including damage to lateral or posterolateral structures, injury to the meniscus, disruption of anterolateral soft tissue structures, or increased tibial slope. In the setting of revision or primary ACL reconstruction with persistent anterolateral laxity, despite repair or reconstruction of other injured structures or in the setting of increased tibial slope, a lateral extra-articular tenodesis procedure can be used to augment an ACL reconstruction to aid in restoring anterolateral rotational stability and to upload the ACL reconstruction graft. This article details our technique for performing a modified Lemaire lateral extra-articular tenodesis using iliotibial band autograft as an adjunct to ACL reconstruction.

High Risk of Tunnel Convergence in Combined Anterior Cruciate Ligament Reconstruction and Lateral Extra-articular Tenodesis

Background: Lateral extra-articular tenodesis (LET) is being increasingly added to primary and revision anterior cruciate ligament (ACL) reconstruction to address residual anterolateral rotatory instability. However, currently there is a lack of knowledge on how close the femoral tunnels are when combining these procedures. Purpose/Hypotheses: To assess the risk of tunnel convergence in combined ACL and LET procedures using 2 different surgical techniques (Lemaire and MacIntosh). It was hypothesized that the risk of tunnel convergence would be greater when using the more distally located Lemaire position. The authors further hypothesized that tunnel proximity would be influenced by knee size. Study Design: Controlled laboratory study. Methods: Ten fresh-frozen cadaveric knees were used for this study. In each specimen, an anatomic ACL femoral tunnel and 2 LET tunnels were drilled using the Lemaire and MacIntosh positions, respectively. After knee dissection, minimal distances between each ACL and LET tunnel were directly measured on the lateral femoral cortex. Furthermore, computed tomography scans were obtained to measure intertunnel convergence and lateral femoral condyle (LFC) width. On the basis of the average LFC width, knees were divided into large and small knees to determine a relationship between knee size and tunnel convergence. Results: Convergence of ACL and LET tunnels occurred in 7 of 10 cases (70%) using the Lemaire attachment position. All tunnel collisions occurred directly on the lateral femoral cortex, while intertunnel (intramedullary) conflicts were not observed. Collisions emerged in both small (n = 4) and large (n = 3) knees. Critical tunnel convergence did not occur using the MacIntosh position. The mean minimal distance between the LET and ACL tunnel using the Lemaire and MacIntosh positions was 3.1 ± 4.6 mm and 9.8 ± 5.4 mm, respectively. Conclusion: Tunnel convergence was more frequently observed in combined ACL and LET reconstruction using the Lemaire technique, independent of the knee size. LET femoral tunnel positioning according to the MacIntosh reconstruction was not associated with tunnel collision. Clinical Relevance: These findings help to raise the awareness for the risk of tunnel convergence in combined ACL and LET procedures. Surgeons may contemplate adjustments on the ACL femoral tunnel drilling technique or fixation device when applying an additional Lemaire procedure. However, in the absence of clinical outcome studies comparing different LET techniques, it remains unclear which technique is superior in a clinical setting.

Anterolateral Ligament of the Knee: Diagnosis, Indications, Technique, Outcomes

In the context of anterior cruciate ligament reconstruction surgery, anterolateral ligament reconstruction is now recognized as a reliable option to control rotatory instability and should be considered in the knee surgeon's modern armamentarium. By highlighting its daily practical application, this infographic presents the indications for this specific additional lateral augmentation, the anatomic and biomechanical principles that underline its rationale, and the clinical outcomes from recent large series.In 2013, Claes et al. updated the anterolateral ligament (ALL) concept, and numerous subsequent studies detailed its precise anatomy. It is now accepted that the femoral insertion is located proximal and posterior to the epicondyle. The biomechanical behavior of the ALL during the knee flexion path has been reported to provide control of tibial internal rotation during the pivot shift and with increasing knee flexion angles (>35). Clinically, when a patient presents with an anterior cruciate ligament (ACL) injury, clinical examination (pivot shift test), radiography (Segond fracture), ultrasound, and 3-dimensional magnetic resonance imaging are useful to assess a combined ALL injury.The following indications for ALL reconstruction are now well established: ACL revision, high-grade pivot shift test, chronic ACL rupture, young patients, pivoting activities, and patients undergoing medial meniscus repair. It has been reported that anatomic and minimally invasive surgical techniques that control anterolateral rotatory instability can achieve successful outcomes without specific complications. Finally, the addition of ALL reconstruction does not delay postoperative rehabilitation, and no modification is required for an early rehabilitation protocol.

Anatomic lateral ankle ligament reconstruction with the semitendinosus graft

Stabilization of severe anterolateral rotatory instability of the ankle joint. Major ankle instability, rerupture after ligament reconstruction, generalized ligament laxity. Minor instabilities, degenerative joint disease, underlying complex deformities like cavovarus. Insufficient lateral ankle ligaments are replaced by an autologous semitendinosus graft. Three small incisions are used to position the graft anatomically under direct view with two fibular bone tunnels and bony fixation with interference screws. Early functional treatment with weight-bearing as tolerated in awalker. In all, 22patients have been treated with the described technique with good stabilization in all cases. Two complications were observed: Too short graft in one patient and postoperative suture granuloma in another case.

Update on Failure Analysis of Implants in ACL Surgery: Technical Failure or Fate?

Reasons for failure of anterior cruciate ligament (ACL) reconstructions are manifold and require a multifactorial explanatory approach. In addition to technical failures, many modifiable and non-modifiable risk factors for a new ACL injury have to be considered. Technical failures primarily include non-anatomical tibial and femoral tunnel position. In comparison to the transtibial drilling technique, the tibial tunnel-independent technique results in a more anatomical position of the femoral tunnel and should therefore be preferred. One can differentiate between non-modifiable and modifiable risk factors. At the same time, the combination of more than one risk factor increases the risk of injury significantly. Non-modifiable risk factors include genetic predisposition, female sex, young age and ligament hyperlaxity. Young age at the time of the first injury is the most important risk factor for graft failure. Modifiable risk factors include high body mass index (BMI), deficits in jump landing mechanics, a steep posterior tibial slope and narrow intercondylar notch width. Neuromuscular training or additional surgical procedures modify these risk factors and reduce the probability of further injuries. A high tibial osteotomy (HTO) is the surgical procedure of choice for a reduction in the posterior tibial slope and anterior tibial translation. In case of a tibial slope over 12°, this procedure should be considered. In revision anterior cruciate ligament reconstructions with remaining anterolateral rotatory instability, additional lateral extraarticular tenodesis should be taken into account. This is also recommended for patients participating in pivoting sports, having concomitant hyperlaxity or additional injury of peripheral structures with insufficiency of the ACL. In addition, the surface of the pitch can be modified and thus influence the risk of an ACL injury. In summary, a substantiated failure analysis is required to initiate specific and individualised therapy - not only in the case of ACL rerupture. These factors should already be considered in risk assessment during patient information.

Magnetic resonance imaging appearances of the capsulo-osseous layer of the iliotibial band and femoral attachments of the iliotibial band in the normal and pivot-shift ACL injured knee

BackgroundBiomechanical evidence suggests that the anterolateral structures of the knee may be important restraints against anterolateral rotatory instability (ALRI) in the setting of anterior cruciate ligament (ACL) injury.ObjectiveTo describe the anatomy and presence of injury of the capsule-osseous layer of the iliotibial band (CITB), the iliotibial band, and its deep distal femoral attachments in patients with a ‘normal’ knee (no pivot-shift bone marrow edema (BME) pattern) and patients with a pivot-shift BME pattern indicative of a pivot-shift injury associated with ACL tears.MethodsGroup 1: 20 consecutive patients with no MRI evidence of pivot-shift injury and group 2: 20 consecutive patients with a pivot-shift BME pattern on MRI were identified. Retrospective consensus analysis of the anatomy and appearances of the CITB and the ‘proximal’ and ‘epicondylar’ distal femoral attachments of the ITB was performed for each MRI by two experienced musculoskeletal radiologists.ResultsThe positive predictive value (PPV) of CITB injury for pivot-shift ACL injury was 74%, negative predicted Value (NPV) was 80%. The PPV for injury of the ‘proximal’ ITB femoral attachment with pivot-shift ACL injury was 93%, NPV was 84%. The PPV for ‘epicondylar’ iliotibial femoral attachment injury was 62%, NPV was 45%.ConclusionsInjury of the CITB and ‘proximal’ deep femoral attachments of the ITB are good markers for ACL injury even in the absence of a Segond fracture and should be evaluated on all MRIs as they may prove important in the further management of ALRI.

Anterolateral stabilization using the modified Lemaire technique for ACL deficiency

Treatment of persistent anterolateral knee instability. Subjective/objective (rotational) instability of the knee after anatomic anterior cruciate ligament (ACL) reconstruction. ACL re-rupture including special demands (e.g., high-performance athletes, hyperlaxity) RELATIVE CONTRAINDICATIONS: Osteoarthritis, additional instability of the knee, which should be treated independently; non-anatomic ACL reconstruction with persisting instability should be treated first with anatomic ACL reconstruction. General contraindications for surgery (e. g. septic arthritis), acute irritation of the affected knee. Supine position. Incision along the proximal lateral femoral epicondyle. Marking of the needed width and length of the iliotibial band (ITB) graft. Passing the ITB graft underneath the lateral collateral ligament. Find and mark the isometric point for fixation next to the lateral femoral epicondyle. Fixation of the ITB graft. Layered wound closure. Knee brace for at least 6weeks. Range of motion (RoM): from postoperative day1: flexion-extension 90-0-0°; first 2weeks after surgery: partial weight bearing (20 kg). An anterolateral extra-articular reconstruction may reduce apersistent anterolateral rotatory instability as well as the re-rupture rate following ACL reconstruction with good patient-reported short-term outcomes. Based on current (biomechanical) data, anterolateral tenodesis seems to be superior to areconstruction of the anterolateral ligament. If atenodesis is performed, the graft should be fixed in an isometric position, with neutral rotation of the knee and low graft tension to avoid extraphysiologic load within the lateral compartment. Indications for such aprocedure may include ahigh-grade pivot shift or revision ACL reconstruction as well as apersistent anterolateral rotatory instability following anatomic ACL reconstruction.

Knee hyperextension and a small lateral condyle are associated with greater quantified antero-lateral rotatory instability in the patients with a complete anterior cruciate ligament (ACL) rupture.

To identify factors associated with quantified rotatory stability (pivot-shift phenomenon) in the anterior cruciate ligament (ACL)-injured knee joint. A consecutive sample of 54 patients who were diagnosed with an ACL injury and admitted to our hospital to undergo ACL reconstruction were enrolled in this study. Antero-lateral rotatory laxity of the knee joint was quantified using a Kinematic Rapid Assessment device (KiRA; Orthokey LTD) under spinal block before initiating reconstruction of the ACL. Univariate and multivariate regressions were performed assuming relationships between patient characteristics (independent variables) and quantified antero-lateral rotatory stability (a dependent variable). It was observed that a low BMI (t = - 1.659, n.s.), greater passive knee extension angle (t = 2.374, P = 0.023), and a narrower lateral femoral condyle width index (t = - 1.712, n.s.) could be candidates associated with the antero-lateral rotatory instability, using univariate analysis. Employing multivariate analysis controlling for these three variables, that the range of passive knee extension was found to be significantly associated with antero-lateral rotatory instability in the ACL-injured knee joint (t = 2.21, P = 0.035). Patients were then divided into two groups (pivot-shift negative versus positive groups) based on the KiRA-documented quantified pivot-shift test. Interestingly, 23.3% of patients were pivot-shift negative, even though their ACL was confirmed as a complete rupture by arthroscopic observations. The degree of passive knee extension was 2.3 ± 4.5 (mean ± SD) in the pivot-shift negative group, while it was 6.8 ± 6.6 in the pivot-shift positive group (n.s.). The lateral femoral condyle width index was 36.6 ± 2.0% in the pivot-shift negative group, and it was significantly wider than in the pivot-shift positive group (33.8 ± 2.6%, P = 0.0046). Finally, we estimated that the risk of positive pivot-shift depends on the degree of knee extension. The logistic regression analysis revealed that genu recurvatum significantly increased the odds ratio for positive pivot-shift (OR = 3.08, P = 0.047, 95% CI = 1.017-9.350). This study revealed that greater antero-lateral rotatory instability in patients with a complete ACL rupture was associated with genu recurvatum and small lateral femoral condyle. These factors should be considered as predictors of a poor outcome from an ACL reconstruction due to a higher load on the ACL graft, and therefore, the attending physicians should modify the treatment strategies accordingly. This study indicates that joint hyperlaxity and bone morphology contribute to the rotational stability of the knee joint, in addition to the ACL and antero-lateral complex (ALC). IV.

Modified Lemaire extra-articular stabilisation of the knee for the treatment of anterolateral instability combined with diffuse pigmented villonodular synovitis: a case report

BackgroundDiffuse pigmented villonodular synovitis (PVNS) of the knee is a rare proliferative joint disease associated with high recurrence rates following surgical treatment. Intra-articular joint instability in conjunction with PVNS implies complex reconstructive strategies due to the destructive nature of the disease.Case presentationHere, we present the case of a young patient with refractory PVNS and a chronic ipsilateral anterior cruciate ligament (ACL) rupture. Clinically, the patient presented with a grade 3 pivot shift phenomenon, indicating anterolateral rotational instability. Usually, PVNS implies a contraindication for ACL reconstruction due to the degenerative and pro-inflammatory joint microenvironment that is induced and maintained by PVNS. Therefore, we have performed a modified Lemaire extra-articular stabilization resulting in significant clinical improvement and subjective joint stability. In the latest follow-up examination at 12 months, the patient reported subjective joint stability and no swelling. In the clinical examination, the patient showed dynamic joint stability during walking. Additionally, the patient presented with grade 0 in pivot-shifting compared to the contralateral knee. The Lachman test exhibited no increased side-to-side difference and a firm endpoint.ConclusionsExtra-articular anterolateral stabilisation of the knee in patients having anterolateral knee instability combined with PVNS is a safe and efficient surgical treatment option yielding significant clinical improvement as well as subjective joint stability.

A novel test for assessment of anterolateral rotatory instability of the knee: the tibial internal rotation test (TIR test)

BackgroundRotational instability of the knee may persist after anterior cruciate ligament (ACL) reconstruction, which may be due to insufficiency of anterolateral stabilizing structures. However, no reliable diagnostic tool or physical examination test is available for identifying patients with anterolateral rotatory instability (ALRI). As shown in cadaveric studies, static internal rotation of the knee is increased in higher flexion angles of the knee after severing the anterolateral structures. This might also be the case in patients with an ACL-deficient knee and concomitant damage to the anterolateral structures. The objective of this study is to assess anterolateral rotatory instability of the knee during physical examination with a tibial internal rotation test.MethodsACL-injured knees of 52 patients were examined by two examiners and side-to-side differences were compared. Both lower legs were internally rotated by applying manual internal rotation torque to both feet in prone position with the knees in 30°, 60° and 90° of flexion. For quantification of the amount of rotation in degrees, a torque adapter on a booth was used. Intra-rater, inter-rater and rater-device agreement were determined by calculating kappa (κ) for the tibial internal rotation test.ResultsTibial internal rotation is increased in 19.2% of the patients with ACL injury according to the tibial internal rotation test. Good intra-rater agreement was found for the tibial internal rotation test, κC = 0.63 (95%CI -0.02-1.28), p = 0.015. Fair inter-rater agreement was found, κF = 0.29 (95%CI 0.02–0.57), p = 0.038. Good rater-device agreement was found, κC = 0.62 (95%CI 0.15–1.10), p = 0.001.ConclusionThe tibial internal rotation test shows increased tibial internal rotation in a small amount of patients with ACL injury. Even though no gold standard for assessment of increased tibial internal rotation of the knee is available yet, the test can be of additional value. It can be used for assessment of internal rotatory laxity of the knee as part of ALRI in addition to the pivot shift test. No clinical implications should yet be based on this test alone.

Lateral Augmentation Procedures in Anterior Cruciate Ligament Reconstruction: Anatomic, Biomechanical, Imaging, and Clinical Evidence

Background: There has been an increasing interest in lateral-based soft tissue reconstructive techniques as augments to anterior cruciate ligament reconstruction (ACLR). The objective of these procedures is to minimize anterolateral rotational instability of the knee after surgery. Despite the relatively rapid increase in surgical application of these techniques, many clinical questions remain. Purpose: To provide a comprehensive update on the current state of these lateral-based augmentation procedures by reviewing the origins of the surgical techniques, the biomechanical data to support their use, and the clinical results to date. Study Design: Systematic review. Methods: A systematic search of the literature was conducted via the Medline, EMBASE, Scopus, SportDiscus, and CINAHL databases. The search was designed to encompass the literature on lateral extra-articular tenodesis (LET) procedures and the anterolateral ligament (ALL) reconstruction. Titles and abstracts were reviewed for relevance and sorted into the following categories: anatomy, biomechanics, imaging/diagnostics, surgical techniques, and clinical outcomes. Results: The search identified 4016 articles. After review for relevance, 31, 53, 27, 35, 45, and 78 articles described the anatomy, biomechanics, imaging/diagnostics, surgical techniques, and clinical outcomes of either LET procedures or the ALL reconstruction, respectively. A multitude of investigations were available, revealing controversy in addition to consensus in several categories. The level of evidence obtained from this search was not adequate for systematic review or meta-analysis; thus, a current concepts review of the anatomy, biomechanics, imaging, surgical techniques, and clinical outcomes was performed. Conclusion: Histologically, the ALL appears to be a distinct structure that can be identified with advanced imaging techniques. Biomechanical evidence suggests that the anterolateral structures of the knee, including the ALL, contribute to minimizing anterolateral rotational instability. Cadaveric studies of combined ACLR-LET procedures demonstrated overconstraint of the knee; however, these findings have yet to be reproduced in the clinical literature. The current indications for LET augmentation in the setting of ACLR and the effect on knee kinematic and joint preservation should be the subject of future research.

Anterolateral rotatory instability in vivo correlates tunnel position after anterior cruciate ligament reconstruction using bone-patellar tendon-bone graft.

AIMTo quantitatively assess rotatory and anterior-posterior instability in vivo after anterior cruciate ligament (ACL) reconstruction using bone-patellar tendon-bone (BTB) autografts, and to clarify the influence of tunnel positions on the knee stability.METHODSSingle-bundle ACL reconstruction with BTB autograft was performed on 50 patients with a mean age of 28 years using the trans-tibial (TT) (n = 20) and trans-portal (TP) (n = 30) techniques. Femoral and tibial tunnel positions were identified from the high-resolution 3D-CT bone models two weeks after surgery. Anterolateral rotatory translation was examined using a Slocum anterolateral rotatory instability test in open magnetic resonance imaging (MRI) 1.0-1.5 years after surgery, by measuring anterior tibial translation at the medial and lateral compartments on its sagittal images. Anterior-posterior stability was evaluated with a Kneelax3 arthrometer.RESULTSA total of 40 patients (80%) were finally followed up. Femoral tunnel positions were shallower (P < 0.01) and higher (P < 0.001), and tibial tunnel positions were more posterior (P < 0.05) in the TT group compared with the TP group. Anterolateral rotatory translations in reconstructed knees were significantly correlated with the shallow femoral tunnel positions (R = 0.42, P < 0.01), and the rotatory translations were greater in the TT group (3.2 ± 1.6 mm) than in the TP group (2.0 ± 1.8 mm) (P < 0.05). Side-to-side differences of Kneelax3 arthrometer were 1.5 ± 1.3 mm in the TT, and 1.7 ± 1.6 mm in the TP group (N.S.). Lysholm scores, KOOS subscales and re-injury rate showed no difference between the two groups.CONCLUSIONAnterolateral rotatory instability significantly correlated shallow femoral tunnel positions after ACL reconstruction using BTB autografts. Clinical outcomes, rotatory and anterior-posterior stability were overall satisfactory in both techniques, but the TT technique located femoral tunnels in shallower and higher positions, and tibial tunnels in more posterior positions than the TP technique, thus increased the anterolateral rotation. Anatomic ACL reconstruction with BTB autografts may restore knee function and stability.

An in Vivo Simulation of Isometry of the Anterolateral Aspect of the Healthy Knee.

To assess the isometry of theoretical lateral extra-articular reconstruction (LER), we evaluated theoretical grafts attached to various points on the lateral femoral condylar area and to either Gerdy's tubercle or the anatomic attachment site of the anterolateral ligament to the tibia. In 18 subjects, healthy knees with no history of either injury or surgery involving the lower extremity were studied. The subjects performed a sit-to-stand motion (from approximately 90° of flexion to full extension), and each knee was studied using magnetic resonance and dual fluoroscopic imaging techniques. The 3-dimensional wrapping paths of each theoretical LER graft were measured. Grafts showing the least change in length during the sit-to-stand motion were considered to be the most isometric. The most isometric attachment site on the lateral femoral epicondyle to either of the studied tibial attachment sites was posterior-distal to the femoral attachment site of the fibular collateral ligament. The LER graft had a mean change in length of approximately 3%. Moving the femoral attachment site anteriorly resulted in increased length of the graft with increasing flexion; more posterior attachment sites resulted in decreased length with increasing flexion. Moving the attachment site in the proximal-distal direction had a less profound effect. Moving the tibial attachment site from Gerdy's tubercle to the tibial attachment site of the anterolateral ligament affected the overall isometric distribution on the lateral femoral epicondyle. The most isometric attachment site on the femur for an LER would be posterior-distal to the femoral attachment site of the fibular collateral ligament. Different length changes for LER grafts were identified with respect to different femoral attachment sites. Desirable graft fixation locations for treating anterolateral rotatory instability were found posterior-proximal to the femoral fibular collateral ligament attachment. The present data could be used both in biomechanical studies and in clinical studies as guidelines for planning LER surgical procedures.

Role of the anterolateral complex in rotatory instability of the anterior cruciate ligament deficient knee

The anterolateral complex (ALC) of the knee plays an important role in rotatory knee stability, especially in anterior cruciate ligament (ACL)-deficient patients. There is considerable awareness of anterolateral rotatory instability secondary to reported high failure rates after ACL reconstruction. As such, there has been a renewed interest in lateral extra-articular reconstruction procedures to stabilize the ALC. The concept of lateral extra-articular tenodesis (EAT) as the sole treatment of ACL injuries was popular in the 1970s, but fell out of favor due to unacceptably poor long-term outcomes. However, as greater understanding of rotatory knee instability has evolved, lateral stabilization procedures similar to those described in the 1970s have emerged to augment ACL reconstruction. These additional soft tissue techniques are not without risk, as many studies have demonstrated knee over-constraint after these procedures. Therefore, it is prudent to take an individualized approach to ACL reconstruction and to assess the value of additional soft tissue procedures in the face of persistent rotatory laxity. This review will address the role of the ALC in rotatory knee injury, the difficulty in diagnosing these injuries, and provide an objective review of additional stabilizing procedures after ACL reconstruction.

Postoperative Knee Joint Stability Following Anterior Cruciate Ligament Reconstruction Using the Ligament Advanced Reinforcement System.

One of the goals of the synthetic materials used in knee joint reconstruction of the anterior cruciate ligament (ACL) is to improve the strength and stability of the graft immediately after the reconstruction. One of the synthetic grafts is a non-absorbable synthetic ligament device made of terephthalic polyethylene polyester fibers, the Ligament Advanced Reinforcement System (LARS). The aim of the study was to assess postoperative knee joint stability in patients who had undergone ACL reconstruction using the LARS graft. The study group was comprised of 20 males who had undergone primary unilateral intraarticular ACL reconstruction using LARS. The patients were evaluated one day before the reconstruction and an average of six weeks postoperatively. Knee stability was evaluated manually using the Lachman test, anterior drawer test and pivot-shift test. Knee active range of motion (ROM) was measured. Preoperatively, the Lachman test indicated abnormal/2+ results in the vast majority of the patients. The postoperative results in most of the patients were normal/0. The anterior drawer test results were also abnormal/2+ preoperatively and normal/0 postoperatively. The pivot-shift test was positive in all of the patients before the ACL reconstruction and negative after the surgery. In general, no differences were found in the ROM between the involved and uninvolved limbs and in the between-measurement comparison. The evaluation demonstrated significant progress from the preoperative to postoperative results in reducing anterior translation and anterolateral rotational instability of the tibia in patients who had undergone ACL reconstruction using the synthetic LARS graft. In the short-term follow-up assessments, restoration of anterior and anterolateral rotational stability of the operated knee joints was observed.

Biomechanical Role of Lateral Structures in Controlling Anterolateral Rotatory Laxity: The Iliotibial Tract

Recent research, focusing on rotatory knee laxity, has intrigued the whole orthopaedic knee community. First popularized by Hughston et al, peripheral knee injuries at the time of cruciate ligament rupture have regained more and more recognition, which has led to a better understanding of these injuries. Recent research has been focused on anterolateral rotatory instability, especially regarding those structures that are responsible for the high-grade anterior subluxation of the lateral tibial plateau when damaged. Work at Imperial College London showed that the iliotibial tract (ITT) was the primary restraint to internal tibial rotation, especially the capsulo-osseous layer of the ITT, which contributed almost 25% of controlling a 5-Nm internal rotation torque at early flexion angles. However, due to the complex fiber arrangement, the functional anatomy of the ITT is difficult to understand. Thus, this article focuses on the involvement of the internal tibial rotation in restraining internal rotation and the pivot-shift phenomenon.

The Fascia Lata Anterolateral Tenodesis Technique

A technique for anatomic reconstruction of the anterolateral complex addressing anterolateral rotatory instability both in primary anterior cruciate ligament reconstruction and in revision cases is presented. The extra-articular reconstruction is performed with a pedicle strip of iliotibial tract, fixed on the anatomic origin and insertion points of the anterolateral ligament of the knee in a double-bundle V-shaped fashion.