The anterolateral complex of the knee: a pictorial essay

Loop technique for anterior cruciate ligament reconstruction combined with anterolateral structure reinforcement: technical description and clinical results

PURPOSE

We describe a surgical technique for ACL reconstruction combined with anterolateral structure reinforcement and report early clinical follow-up results.

METHODS

The semitendinosus and gracilis tendons are braided into 5 strands and the ACL femoral tunnel and tibial tunnel are created. The graft is passed through the tunnel with the use of a traction suture and the tibial end is fixed with absorbable interference screws at 30° of knee flexion. The ACL graft traction suture is used as an anterolateral reconstruction structure to pass through the proximal exit of the ACL femoral tunnel and then through the depth of the iliotibial bundle to the anterior to Gerdy's tubercle, a bony tunnel is created from the anterior to Gerdy's tubercle to the goose foot, and the traction suture is passed through this bony tunnel to form a Loop structure at 20° of knee flexion. Between March 2021 and May 2022 IKDC score, Lysholm score, and Tegner score were performed preoperatively and 6-12 months postoperatively in 24 consecutive patients who met the indications for this procedure and underwent surgery. The patient's maximum flexion angle, the circumference of the thigh, and the stress X-ray between the operated and healthy knee were measured.

RESULTS

Patients showed significant improvement in IKDC score, Lysholm score and Tegner score at a mean follow-up of 7 months postoperatively compared to preoperatively. No significant increase in anterior tibial displacement was found between the patient's operated side and the healthy side.

CONCLUSION

The Loop technique ACLR combined with ALSA can be used in patients with an ACL tear combined with a high degree of positive pivot shift. The patient's subjective perception was significantly improved from the preoperative period and knee stability was restored.

LEVEL OF EVIDENCE

IV, therapeutic study.

Exposure of Hoffa Fractures Is Improved by Posterolateral and Posteromedial Extensile Approaches: A Qualitative and Quantitative Anatomical Study

BACKGROUND

The current literature lacks recommendations regarding surgical approaches to best visualize and reduce Hoffa fractures. The aims of this study were to (1) define surgical corridors to the posterior portions of the lateral and medial femoral condyles and (2) compare the articular surface areas visible with different approaches.

METHODS

Eight fresh-frozen human cadaveric knees (6 male and 2 female donors; mean age, 68.2 ± 10.2 years) underwent dissection simulating 6 surgical approaches to the distal femur. The visible articular surface areas for each approach were marked using an electrocautery device and subsequently analyzed using image-processing software. The labeled areas of each femoral condyle were statistically compared.

RESULTS

At 30° of flexion, visualization of the posterior portions of the lateral and medial femoral condyles was not possible by lateral and medial parapatellar approaches, as only the anterior 29.4% ± 2.1% of the lateral femoral condyle and 25.6% ± 2.8% of the medial condyle were exposed. Visualization of the lateral femoral condyle was limited by the posterolateral ligamentous structures, hence a posterolateral approach only exposed its central (13.1% ± 1.3%) and posterior (12.4% ± 1.1%) portions. Posterolateral extension by an osteotomy of the lateral femoral epicondyle significantly improved the exposure to 53.4% ± 2.7% and, when combined with a Gerdy's tubercle osteotomy, to 70.9% ± 4.1% (p < 0.001). For the posteromedial approach, an arthrotomy between the anteromedial retinaculum and the superficial medial collateral ligament, and one between the posterior oblique ligament and the medial gastrocnemius tendon, allowed visualization of the central (13.5% ± 2.2%) and the posterior (14.6% ± 2.3%) portions of the medial femoral condyle, while a medial femoral epicondyle osteotomy significantly improved visualization to 66.1% ± 5.5% (p < 0.001).

CONCLUSIONS

Visualization of the posterior portions of the femoral condyles is limited by the specific anatomy of each surgical corridor. Extension by osteotomy of the femoral epicondyles and Gerdy's tubercle significantly improved articular surface exposure of the femoral condyles.

CLINICAL RELEVANCE

Knowledge of the surgical approach-specific visualization of the articular surface of the femoral condyles might be helpful to properly reduce small Hoffa fragments.

Evaluation of Failed ACL Reconstruction: An Updated Review

Failure rates among primary Anterior Cruciate Ligament Reconstruction (ACLR) range from 3.2% to 11.1%. Recently, there has been increased focus on surgical and anatomic considerations which predispose patients to failure, including excessive posterior tibial slope (PTS), unaddressed high-grade pivot shift, and improper tunnel placement. The purpose of this review was to provide a current summary and analysis of the literature regarding patient-related and technical factors surrounding revision ACLR, rehabilitation considerations, overall outcomes and return to sport (RTS) for patients who undergo revision ACLR. There is a convincingly higher re-tear and revision rate in patients who undergo ACLR with allograft than autograft, especially amongst the young, athletic population. Unrecognized Posterior Cruciate Ligament (PLC) injury is a common cause of ACLR failure and current literature suggests concurrent operative management of high-grade PLC injuries. Given the high rates of revision surgery in young active patients who return to pivoting sports, the authors recommend strong consideration of a combined ACLR + Anterolateral Ligament (ALL) or Lateral extra-articular tenodesis (LET) procedure in this population. Excessive PTS has been identified as an independent risk factor for ACL graft failure. Careful consideration of patient-specific factors such as age and activity level may influence the success of ACL reconstruction. Additional technical considerations including graft choice and fixation method, tunnel position, evaluation of concomitant posterolateral corner and high-grade pivot shift injuries, and the role of excessive posterior tibial slope may play a significant role in preventing failure.

Shear wave elastography demonstrates different material properties between the medial collateral ligament and anterolateral ligament

BACKGROUND

Anterolateral ligament and medial collateral ligament injuries could happen concomitantly with anterior cruciate ligament ruptures. The anterolateral ligament is injured more often than the medial collateral ligament during concomitant anterior cruciate ligament ruptures although it offers less restraint to knee movement. Comparing the material properties of the medial collateral ligament and anterolateral ligament helps improve our understanding of their structure-function relationship and injury risk before the onset of injury.

METHODS

Eight cadaveric lower extremity specimens were prepared and mechanically tested to failure in a laboratory setting using a hydraulic platform. Measurements of surface strains of superficial surface of each medial collateral ligament and anterolateral ligament specimen were found using three-dimensional digital image correlation. Ligament stiffness was found using ultrasound shear-wave elastography. t-tests were used to assess for significant differences in strain, stress, Young's modulus, and stiffness in the two ligaments.

FINDINGS

The medial collateral ligament exhibited greater ultimate failure strain along its longitudinal axis (p = 0.03) and Young's modulus (p < 0.0018) than the anterolateral ligament. Conversely, the anterolateral ligament exhibited greater ultimate failure stress than the medial collateral ligament (p < 0.0001). Medial collateral ligament failure occurred mostly in the proximal aspect of the ligament, while most anterolateral ligament failure occurred in the distal or midsubstance aspect (P = 0.04).

INTERPRETATION

Despite both being ligamentous structures, the medial collateral ligament and anterolateral ligament exhibited separate material properties during ultimate failure testing. The weaker material properties of the anterolateral ligament likely contribute to higher rates of concomitant injury with anterior cruciate ligament ruptures.

The Role of Anterolateral Ligament Reconstruction or Lateral Extra-articular Tenodesis for Revision Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis of Comparative Clinical Studies

BACKGROUND

After its success in restoring rotational stability and reducing failure rates in primary anterior cruciate ligament reconstruction (ACLR), lateral extra-articular tenodesis (LET) or anterolateral ligament reconstruction (ALLR) has been endorsed for use in revision ACLR surgery, where failure rates are historically higher.

PURPOSE

To perform a systematic review and meta-analysis on whether the addition of a LET or ALLR results in superior clinical outcomes and stability compared with isolated revision ACLR (iACLR).

STUDY DESIGN

Meta-analysis; Level of evidence, 4.

METHODS

The Cochrane Controlled Register of Trials, PubMed, Medline, and Embase were used to perform a systematic review and meta-analysis of comparative studies using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria with the following search terms: ("extra-articular" OR "tenodesis" OR "anterolateral ligament" OR "iliotibial") AND ("anterior cruciate ligament") AND ("revision" OR "re-operation"). Data pertaining to all patient-reported outcome measures (PROMs), rotational stability, and postoperative complications were extracted from each study.

RESULTS

After abstract and full-text screening, 10 clinical comparative studies were included. There were 793 patients, of whom 390 had an iACLR while 403 had an ACLR augmented with a LET or an ALLR (augmented ACLR [aACLR]). The mean time for assessment of PROMs was 35 months. The aACLR group had superior International Knee Documentation Committee (IKDC) scores (standardized mean difference [SMD], 0.27; 95% CI, 0.01 to 0.54; P = .04), rotational stability (odds ratio [OR], 2.77; 95% CI, 1.91 to 4.01; P < .00001), and lower side-to-side difference (OR, -0.53; 95% CI, -0.81 to -0.24; P = .0003) than those without the augmentation. Furthermore, they were less likely to fail (OR, 0.44; 95% CI, 0.24 to 0.80; P = .007). Subgroup analysis in the higher-grade laxity cohort (grade ≥2) revealed an even greater IKDC score (SMD, 0.51; 95% CI, 0.16 to 0.86; P = .005) and an improved Lysholm score (SMD, 0.45; 95% CI, 0.24 to 0.67; P < .0001) in the aACLR group.

CONCLUSION

Revision aACLR with a LET or an ALLR can improve subjective IKDC scores, restore rotational stability, and reduce failure rates compared with iACLR. Although controversy remains on the necessity of augmenting all revision ACLRs, the present meta-analysis advocates adding a lateral procedure, particularly in those with a higher-grade pivot shift.

Comparison of Revision ACL Reconstruction Using Iliotibial Band Augmented With Allograft Versus Bone-Patellar Tendon-Bone Autograft With Lateral Extra-articular Tenodesis

Background

Bone-patellar tendon-bone (BTB) anterior cruciate ligament reconstruction (ACLR) is one of the conventional techniques in the revision setting especially after a primary hamstring tendon graft. The use of the iliotibial band (ITB) augmented with allograft (AG) is an encouraging graft alternative for ACLR in terms of clinical and biomechanical data in the literature.

Purpose

To compare the clinical outcomes of BTB graft with lateral extra-articular tenodesis, modified Lemaire (BTB-LET), and an ITB graft augmented with hamstring AG (ITB-AG) in the setting of revision ACLR.

Study Design

Cohort study; Level of evidence, 3.

Methods

Descriptive data and clinical outcomes were prospectively collected from patients who underwent revision ACLR with either the BTB-LET or ITB-AG technique between 2012 and 2020 and who had a minimum follow-up of 2 years. The clinical outcomes were assessed by the Lysholm, Tegner, Anterior Cruciate Ligament-Return to Sport after Injury, International Knee Documentation Committee subjective knee evaluation form, and Knee injury and Osteoarthritis Outcome Score. Return to sports, complications, and revisions were also analyzed.

Results

A total of 167 patients were included, with 106 patients in the BTB-LET group and 61 patients in the ITB-AG group. There were no significant group differences in sociodemographic characteristics; however, the mean follow-up was significantly longer in the BTB-LET compared with the ITB-AG group (52.0 vs 38.8 months, respectively; P = .0001). There were no significant differences in postoperative outcome scores; however, patients in the ITB-AG group had a higher rate of return to competitive pivoting sports (32.8% vs 17.9%; P = .0288) and a higher overall rate of return to preinjury sport (63.9% vs 47.2%; P = .0365). Complications, including revisions for meniscal or chondral lesions and retears (8 [8.3%] in the BTB-LET group and 2 [4.0%] in the ITB-AG group), were not significantly different. All retears were due to sports-related accidents.

Conclusion

In this study, ITB-AG was not different from BTB-LET in terms of functional outcomes scores but allowed better return to sport rate. Performing ITB-AG reconstruction in the setting of revision ACLR appears to be safe, effective, and associated with a satisfying return-to-sports rate.

High Prevalence of Persistent Measurable Postoperative Knee Joint Laxity in Patients with Tibial Plateau Fractures Treated by Open Reduction and Internal Fixation (ORIF)

The development of post-traumatic osteoarthrosis after tibial plateau fracture (TPF) is multifactorial and can only be partially influenced by surgical treatment. There is no standardized method for assessing pre- and postoperative knee joint laxity. Data on the incidence of postoperative laxity after TPF are limited. The purpose of this study was to quantify postoperative laxity of the knee joint after TPF. Fifty-four patients (mean age 51 ± 11.9 years) were included in this study. There was a significant increase in anterior-posterior translation in 78.0% and internal rotation in 78.9% in the injured knee when compared to the healthy knee. Simple fractures showed no significant difference in laxity compared to complex fractures. When preoperative ligament damage and/or meniscal lesions were present and surgically treated by refixation and/or bracing, patients showed higher instability when compared to patients without preoperative ligament and/or meniscal damage. Patients with surgically treated TPF demonstrate measurable knee joint laxity at a minimum of 1 year postoperatively. Fracture types have no influence on postoperative laxity. This emphasizes the importance of recognizing TPF as a multifaceted injury involving both complex fractures and damage to multiple ligaments and soft tissue structures, which may require further surgical intervention after osteosynthesis.

Surgical Treatment for Avulsion Fractures of the Anterolateral Ligament Associated with Periarticular Fractures of the Knee

The existence and anatomy of the anterolateral ligament (ALL) of the knee are a somewhat controversial topic in orthopaedic surgery. The fixation of the avulsion fracture of the ALL (Segond fracture), associated with periarticular knee fractures, is rarely given much consideration while the major fracture fragments are reconstructed. This study aims to confirm the existence of ALL and evaluate the clinical outcomes of surgical management for avulsion fractures, involving its insertion, when associated with periarticular knee fractures. Twenty-three patients (16 males and 7 females) with avulsion fractures of the ALL associated with periarticular knee fractures were fixed with a spider plate, cannulated screw, or suture anchor. Eight patients were diagnosed with distal femoral fracture, 10 with tibial plateau fracture, and 5 with tibial eminence avulsion fracture. All patients underwent X-rays at follow-up. Clinical and functional outcomes were assessed with the pivot-shift test, objective and subjective International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner activity scale. The ALL was found and identified as a distinct ligamentous structure in all patients. Prior to Segond repair, patients had significantly more instability, as determined by pivot-shift test, than seen postoperatively (p < 0.0001). At final follow-up, the mean subjective IKDC score was 83.2 ± 10.3. Fourteen patients were graded A, 6 were graded B, and 3 was graded C on the IKDC objective score. The mean Lysholm score was 85.4 ± 12.2. The mean Tegner score was 7.5 ± 1.2. This study confirmed that the ALL is a distinct structure in the anterolateral portion of the knee. The fixation of the avulsion fracture of the ALL associated with periarticular knee fractures can be an effective procedure without specific complications. Long-term and comparative follow-up studies are necessary to confirm the effects.

Clinical Outcomes After Anterior Cruciate Ligament Reconstruction in Patients With a Concomitant Segond Fracture: A Systematic Review

BACKGROUND

The Segond fracture can be observed in patients with an anterior cruciate ligament (ACL) tear. It is unclear whether the Segond fracture affects clinical outcomes after ACL reconstruction.

PURPOSE

To investigate whether the presence of a concomitant Segond fracture affects clinical outcomes after ACL reconstruction and to compare clinical outcomes when a Segond fracture is repaired surgically or left unrepaired.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

Three databases (PubMed, Embase, Cochrane Library) were searched in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines on July 27, 2020. Relevant studies regarding ACL injury with concomitant Segond fracture treated by primary ACL reconstruction were screened in duplicate. Data regarding patient characteristics and clinical outcomes were extracted. Descriptive data are presented, and a random-effects model was used to pool amenable data.

RESULTS

A total of 5 studies examining 2418 patients (987 female; 40.8%), mean age 25.4 years, were included in this study. There were 304 patients with a Segond fracture (mean age, 28.1 years; 35.9% female) and 2114 patients without a Segond fracture (mean age, 25.1 years; 41.5% female). Four studies directly compared outcomes between patients with an unrepaired Segond fracture and no Segond fracture. One study reported 12 patients who underwent ACL reconstruction and repair of a Segond fracture. Among 4 studies, 11 of 292 (3.8%) graft failures/revision surgeries were reported in the groups that had Segond fracture, whereas 145 of 2114 (6.9%) graft failures/revision surgeries were reported in groups that did not have Segond fracture. No significant difference was observed in the risk of graft failure between the 2 groups, with a pooled risk ratio of 0.59 (95% CI, 0.32-1.07; P = .08; I2 = 0%). No clinically significant differences were observed with regard to International Knee Document Committee score, Lysholm score, Tegner activity scale, and postoperative knee laxity between the group with Segond fracture and those without.

CONCLUSION

An unrepaired Segond fracture does not appear to have any significant negative effect on postoperative stability or risk of graft failure or revision surgery after ACL reconstruction. Future prospective studies may be warranted to confirm the finding that patients with combined ACL injury and Segond fracture may have outcomes comparable with those of ACL-injured patients without a Segond fracture when isolated ACL reconstruction is performed.

Influence of Injury to the Kaplan Fibers of the Iliotibial Band on Anterolateral Rotatory Knee Laxity in Anterior Cruciate Ligament Injury: A Retrospective Cohort Study

BACKGROUND

Biomechanical cadaveric studies have shown that Kaplan fibers (KFs) of the iliotibial band play a role in controlling anterolateral rotatory knee laxity in anterior cruciate ligament (ACL) injury. However, in the clinical setting, the contribution of injury to KFs on anterolateral rotatory laxity remains unclear.

PURPOSE

To use magnetic resonance imaging (MRI) scans to detect concomitant KF injury in ACL-injured knees and to then examine the effect of KF injury on anterolateral rotatory laxity as measured by the pivot-shift test in a clinical setting.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

The study enrolled 91 patients with primary ACL tears (mean age 25 ± 11 years; 46 male and 45 female) whose MRI was conducted within 90 days after injury. KF injury was assessed by MRI according to previously reported criteria, and the patients were allocated to a KF injury group and a no-KF injury group. At the time of ACL reconstruction, the pivot-shift test was performed with the patient under anesthesia and quantitatively evaluated by tibial acceleration using an electromagnetic measurement system. Manual grading of the pivot-shift test was assessed according to guidelines of the International Knee Documentation Committee. The data were statistically compared between the 2 groups using Mann-Whitney U test and Fisher exact test (P < .05).

RESULTS

KFs were identified in 85 patients (93.4%), and KF injury was detected in 20 of the 85 patients (23.5%). No significant differences were observed between the KF injury group (n = 20) and the no-KF injury group (n = 65) in demographic characteristics, the period from injury to MRI (8.0 ± 14.0 days vs 8.9 ± 12.1 days, respectively), the rate of meniscal injury (50.0% vs 53.8%), or the rate of anterolateral ligament injury (45.0% vs 44.6%). Regarding the pivot-shift test, no significant differences were observed in tibial acceleration (1.2 m/s² [interquartile range, 0.5-2.1 m/s²] vs 1.0 m/s² [interquartile range, 0.6-1.7 m/s²], respectively) or manual grading between the 2 groups.

CONCLUSION

Concomitant KF injury did not significantly affect the pivot-shift phenomenon in acute ACL-injured knees. The findings suggest that the contribution of KF injury to anterolateral rotatory knee laxity may be limited in the clinical setting.

Anterolateral Structure Reconstructions With Different Tibial Attachment Sites Similarly Improve Tibiofemoral Kinematics and Result in Different Graft Force in Treating Knee Anterolateral Instability

PURPOSE

To compare the biomechanical effects of anterolateral structure reconstructions (ALSRs) with different tibial attachments on tibiofemoral kinematics and anterolateral structure (ALS) graft forces.

METHODS

Eight cadaveric knees were tested in a customized knee testing system, using a novel pulley system to simulate more muscle tensions by loading the iliotibial band at 30 N and quadriceps at 10 N in all testing states. Anterior stability during anterior load and anterolateral rotatory stability during 2 simulated pivot-shift tests (PST1 and PST2) were evaluated in 5 states: intact, ALS-deficient (Def), ALSR-Ta (anterior tibial site), ALSR-Tm (middle tibial site), and ALSR-Tp (posterior tibial site). Tibiofemoral kinematics and resulting ALS graft forces against the applied loads were measured and compared in the corresponding states.

RESULTS

In anterior load, 3 ALSRs mitigated the anterior laxities of the ALS Def state at all degrees, which were close to intact state at 0° and 30° but showed significantly overconstraints at 60° and 90°. In both PSTs, all ALSRs significantly reduced the anterolateral rotatory instability of ALS Def, whereas the significant overconstraints were detected in ALSR-Ta and ALSR-Tm at greater knee flexion angles. All ALS grafts carried forces in resisting anterior and pivot-shift loads. Only ALS graft force in ALSR-Ta increased continuously with knee flexion angles. The ALS graft forces carried by ALSR-Ta were significantly larger than those by ALSR-Tp and ALSR-Tm when resisting anterior load and PSTs at greater knee flexion angles.

CONCLUSIONS

ALSRs with different tibial attachment sites similarly restored knee laxities close to the native tibiofemoral kinematics in an ALS-deficient knee, whereas the ALSR-Tp showed less propensity for overconstraining the knee at greater flexion angles. The ALS graft in ALSR-Ta carried more forces than those in ALSR-Tp and ALSR-Tm against simulated loads.

CLINICAL RELEVANCE

Altering the tibial attachment sites of ALSRs may not significantly affect tibiofemoral kinematics at most degrees whereas the posterior may have less overconstraints at greater flexion angles. However, ALS graft positioning at a more anterior tibial attachment site may carry more forces in resisting anterior and pivot-shift loads.

Anterolateral Extraarticular Stabilisation of the Knee: Modified Lemaire Procedure

The anterolateral aspect of the knee is prone to laxity or symptomatic instability, if the anterior cruciate ligament (ACL) is torn. It is necessary to address this issue in patients with general joint hyperlaxity, overextension of the knee, massive anterolateral instability, or re-tear of the ACL with chronic instability. In these cases, and in addition to a preoperative bony workup and revision ACL reconstruction, anterolateral stabilisation should be considered to avoid persistent anterolateral rotation instability and failure of the ACL reconstruction.To stabilise the anterolateral corner of the knee, the modified Lemaire procedure as presented and illustrated here is a straight forward surgical technique that can be performed right after standard ACL reconstruction surgery, if indicated. It is independent from the graft choice for the ACL reconstruction, and the surgical setting in the operating room remains unchanged.

Current trends in the anterior cruciate ligament part II: evaluation, surgical technique, prevention, and rehabilitation

Clinical evaluation and management of anterior cruciate ligament (ACL) injury is one of the most widely researched topics in orthopedic sports medicine, giving providers ample data on which to base their practices. The ACL is also the most commonly treated knee ligament. This study reports on current topics and research in clinical management of ACL injury, starting with evaluation, operative versus nonoperative management, and considerations in unique populations. Discussion of graft selection and associated procedures follows. Areas of uncertainty, rehabilitation, and prevention are the final topics before a reflection on the current state of ACL research and clinical management of ACL injury. Level of evidence V.

Injuries to the anterolateral ligament are observed more frequently compared to lesions to the deep iliotibial tract (Kaplan fibers) in anterior cruciate ligamant deficient knees using magnetic resonance imaging

PURPOSE

To determine the accuracy of detection, injury rate and inter- and intrarater reproducibility in visualizing lesions to the anterolateral ligament (ALL) and the deep portion of the iliotibial tract (dITT) in anterior cruciate ligament (ACL) deficient knees.

METHODS

Ninety-one consecutive patients, out of those 25 children (age 14.3 ± 3.5 years), with diagnosed ACL tears were included. Two musculoskeletal radiologists retrospectively reviewed MRI data focusing on accuracy of detection and potential injuries to the ALL or dITT. Lesion were diagnosed in case of discontinued fibers in combination with intra- or peri-ligamentous edema and graded as intact, partial or complete tears. Cohen's Kappa and 95% confidence intervals (95% CI) were determined for inter- and intrarater reliability measures.

RESULTS

The ALL and dITT were visible in 52 (78.8%) and 56 (84.8%) of adult-and 25 (100%) and 19 (76.0%) of pediatric patients, respectively. The ALL was injured in 45 (58.5%; partial: 36.4%, compleate: 22.1%) patients. Partial and comleate tears, where visualized in 21 (40.4%) and 16 (30.8%) adult- and seven (28.0%) and one (4%) peditric patients. A total of 16 (21.3%; partial: 13.3%, compleate: 8.0%) dITT injuries were identified. Partal and complete lesions were seen in seven (12.5%) and five (8.9%) adult- and three (15.8%) and one (5.3%) pediatric patients. Combined injuries were visualized in nine (12.7%) patients. Inter-observer (0.91-0.95) and intra-observer (0.93-0.95) reproducibility was high.

CONCLUSION

In ACL injured knees, tears of the ALL are observed more frequently compared to lesions to the deep iliotibial tract. Combined injuries of both structures are rare. Clinically, the preoperative visualization of potentially injured structures of the anterolateral knee is crucial and is important for a more personalized preoperative planning and tailored anatomical reconstruction. The clinical implication of injuries to the anterolateral complex of the knee needs further investigation.

LEVEL OF EVIDENCE

II.

Quadriceps tendon autograft is becoming increasingly popular in revision ACL reconstruction

PURPOSE

To evaluate trends in revision anterior cruciate ligament reconstruction (ACL-R), with emphasis on intra-articular findings, grafts, and concurrent procedures. It was hypothesized that revision ACL-Rs over time show a trend toward increased complexity with increased use of autografts over allografts.

METHODS

This was a two-center retrospective study including patients undergoing revision ACL-R between 2010 and 2020. Demographic and surgical data including intra-articular findings and concurrent procedures were collected and compared for the time periods 2010-2014 and 2015-2020. All collected variables were compared between three pre-defined age groups (< 20 years, 20-30 years, > 30 years), right and left knees, and males and females. A time series analysis was performed to assess trends in revision ACL-R.

RESULTS

This study included 260 patients with a mean age of 26.2 ± 9.4 years at the time of the most recent revision ACL-R, representing the first, second, third, and fourth revision ACL-R for 214 (82%), 35 (14%), 10 (4%), and 1 (< 1%) patients, respectively. Patients age > 30 years showed a significantly longer mean time from primary ACL-R to most recent revision ACL-R (11.1 years), compared to patients age < 20 years (2.2 years, p < 0.001) and age 20-30 years (5.5 years, p < 0.05). Quadriceps tendon autograft was used significantly more often in 2015-2020 compared to 2010-2014 (49% vs. 18%, p < 0.001). A high rate of concurrently performed procedures including meniscal repairs (45%), lateral extra-articular tenodesis (LET; 31%), osteotomies (13%), and meniscal allograft transplantations (11%) was shown. Concurrent LET was associated with intact cartilage and severely abnormal preoperative knee laxity and showed a statistically significant and linear increase over time (p < 0.05). Intact cartilage (41%, p < 0.05), concurrent medial meniscal repairs (39%, p < 0.05), and LET (35%, non-significant) were most frequently observed in patients aged < 20 years.

CONCLUSION

Quadriceps tendon autograft and concurrent LET are becoming increasingly popular in revision ACL-R. Intact cartilage and severely abnormal preoperative knee laxity represent indications for LET in revision ACL-R. The high rate of concurrent procedures observed demonstrates the high surgical demands of revision ACL-R.

LEVEL OF EVIDENCE

Level III.

Additional lateral extra-articular tenodesis in revision ACL reconstruction does not influence the outcome of patients with low-grade anterior knee laxity

INTRODUCTION

There is limited evidence on the indications of lateral extra-articular tenodesis (LET) in revision ACLR. The aim of this study was to evaluate the influence of the LET in patients with revision ACLR with preoperative low-grade anterior knee laxity.

METHODS

Between 2013 and 2018, 78 patients who underwent revision ACLR with preoperative low-grade anterior knee laxity [≤ 5 mm side-to-side difference (SSD)] were included in the retrospective cohort study. An additional modified Lemaire tenodesis was performed in 23 patients during revision ACLR and patients were clinically examined with a minimum of 2 years after revision surgery. Postoperative failure of the revision ACLR was defined as SSD in Rolimeter^® testing ≥ 5 mm or pivot-shift grade 2/3.

RESULTS

In total, failure of the revision ACLR occurred in 11.5% (n = 9) of the cases at a mean follow-up of 28.7 ± 8.8 (24-67) months. Patients with an additional LET and revision ACLR did not show a significantly reduced failure rate (13% vs. 11%) or an improved clinical outcome according to the postoperative functional scores or pain in regards to patients with an isolated revision ACLR (Tegner 5.7 ± 1.3 vs. 5.9 ± 1.5, n.s.; IKDC 77.5 ± 16.2 vs. 80.1 ± 14.9, n.s., Lysholm 81.9 ± 14.2 vs. 83.8 ± 14.5, n.s.; VAS 1.9 ± 2.2 vs. 1.2 ± 1.7, n.s.).

CONCLUSIONS

An additional LET in patients with revision ACLR with low-grade anterior knee laxity does not influence patient-related outcomes or failure rates. Subjects with preoperative low-grade anterior knee laxity may not benefit from a LET in revision ACLR.

LEVEL OF EVIDENCE

III.

Common animal models lack a distinct glenoid labrum: a comparative anatomy study

Purpose

Development and validation of an animal model of labral healing would facilitate translation of novel surgical and biological strategies to improve glenolabral healing. The purpose of this study was to characterize the anatomic and histological properties of the shoulder labrum in rat, rabbit, dog, pig, goat, and humans. Given the demonstrated similarities in size and structural morphology in other joints, it was hypothesized that the goat glenoid with surrounding capsulolabral complex would most closely resemble that of humans in terms of dimensions and structure, as observed grossly and histologically.

Methods

Cadaveric glenohumeral joints from rats (n = 8), New Zealand white rabbits (n = 13), Mongrel dogs (n = 9), Spanish goats (n = 10), Yorkshire pigs (n = 10), and humans (n = 9) were freshly harvested. Photographs were taken of the glenoid with its surrounding capsulolabral complex. Linear dimensions of the glenoid articular surface were measured. It was determined where the capsulolabral complex was continuous with, or recessed from, the articular glenoid surface. The glenoid was divided into 6 equal segments radiating out toward 12, 2, 4, 6, 8, and 10 o’clock positions. Samples were sectioned and stained with Safranin O/Fast green and Mallory Trichrome. Insertion of the capsulolabral tissue onto the glenoid was qualitatively assessed and compared with gross morphology.

Results

Dimensions of the goat glenoid most closely paralleled dimensions of the human glenoid. A capsulolabral complex was continuous with the glenoid surface from ~ 9 to 12 o’clock in the rats, 7 to 12 o’clock in rabbits, 5 to 12 o’clock in the dogs, and 9 to 12 o’clock in goats, 6 to 12 o’clock in pigs, and 2 to 8 o’clock in humans. In contrast to humans, no other species demonstrated an organized fibrocartilaginous labrum either macroscopically or histologically.

Conclusion

The animals in the present study did not possess a discrete fibrocartilaginous labrum by gross or histological evaluation, as directly compared to humans. While models using these animals may be acceptable for examining other shoulder pathologies, they are not adequate to evaluate labral pathology.

Level of evidence

Basic Science Study; Anatomy and Histology; Cadaveric Animal Model.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40634-021-00383-6.

High Rate of Initially Overlooked Kaplan Fiber Complex Injuries in Patients With Isolated Anterior Cruciate Ligament Injury

BACKGROUND

Injuries to the Kaplan fiber complex (KFC) are not routinely assessed for in the anterior cruciate ligament (ACL)-deficient knee during preoperative magnetic resonance imaging (MRI). As injuries to the KFC lead to anterolateral rotatory instability (ALRI) in the ACL-deficient knee, preoperative detection of these injuries on MRI scans may help surgeons to individualize treatment and improve outcomes, as well as to reduce failure rates.

PURPOSE

To retrospectively determine the rate of initially overlooked KFC injuries on routine MRI in knees with isolated primary ACL deficiency.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients who underwent isolated ACL reconstruction between August 2013 and December 2019 were identified. No patient had had Kaplan fiber (KF) injury identified on the initial reading of the MRI scan or at the time of surgery. Preoperative knee MRI scans (minimum 1.5 T) were reviewed and injuries to the proximal and distal KFs were recorded by 3 independent reviewers. KF length and distance to nearby anatomic landmarks (the lateral joint line and the lateral femoral epicondyle) were measured. Additional radiological findings, including bleeding, lateral femoral notch sign, and bone marrow edema (BME), were identified to detect correlations with KFC injury.

RESULTS

The intact KFC could reliably be identified by all 3 reviewers (85.9% agreement; Kappa, 0.716). Also, 53% to 56% of the patients with initially diagnosed isolated ACL ruptures showed initially overlooked injuries to the KFC. Injuries to the distal KFs were more frequent (48.1%, 53.8%, and 43.3% by the first, second, and third reviewers, respectively) than injuries to the proximal KFs (35.6%, 47.1%, and 45.2% by the first, second, and third reviewers, respectively). Bleeding in the lateral supracondylar region was associated with KFC injuries (P = .023). Additionally, there was a positive correlation between distal KF injuries and lateral tibial plateau BME (P = .035), but no associations were found with the lateral femoral notch sign or other patterns of BME, including pivot-shift BME.

CONCLUSION

KF integrity and injury can be reliably detected on routine knee MRI scans. Also, 53% to 56% of the patients presenting with initially diagnosed isolated ACL ruptures had concomitant injuries to the KFC. This is of clinical relevance, as ACL injuries diagnosed by current routine MRI examination protocols may come with a high number of occult or hidden KFC injuries. As injuries to the KFC contribute to persistent ALRI, which may influence ACL graft failure or reoperation rates, significant improvements in preoperative diagnostic imaging are required to determine the exact injury pattern and to assist in surgical decision making.

Segond Fractures Involve the Anterolateral Knee Capsule But Not the Iliotibial Band

Purpose

To investigate the relationship between the Segond fracture and the anterolateral complex of the knee.

Methods

Between January 2014 and March 2020, patients who presented with an anterior cruciate ligament (ACL) tear requiring acute surgical reconstruction (within 10 days from trauma) were evaluated for inclusion in this study. Patients were included if they had an acute ACL tear with an associated Segond fracture (or “Segond lesion”) as detected by radiograph or magnetic resonance imaging. The lateral compartment was exposed in all cases using a 5-cm lateral hockey-stick incision, which was carried down to the iliotibial band. The fascia lata was first inspected and then longitudinally divided along its fibers to expose lateral compartment. The posterolateral corner to Gerdy’s tubercle anteriorly was exposed and examined. Once the Segond fracture was identified, it was recorded and photographed.

Results

Seventeen patients were enrolled in the study. Dissection of the Segond fracture demonstrated attachment to the anterolateral capsule only. No other discernible attachment to the Segond fracture was noted. Surgical exploration of the anterolateral knee did not reveal injury to the iliotibial band.

Conclusions

Careful dissection of Segond fractures during repair revealed that there is a discernible attachment with the anterolateral capsule to the bone injury in all patients with acute ACL tears undergoing surgical reconstruction and no connections to the iliotibial band.

Clinical Relevance

The precise pathogenesis of Segond fractures has been the subject of debate, partially due to the complexity of the anatomy of the anterolateral aspect of the knee. Proper understanding of the anatomy of type IV ALL injures with Segond fractures is important to improve treatment of these injuries.

A Secondary Injury of the Anterolateral Structure Plays a Minor Role in Anterior and Anterolateral Instability of Anterior Cruciate Ligament-Deficient Knees in the Case of Functional Iliotibial Band

PURPOSE

To analyze the contribution of a secondary anterolateral structure (ALS) deficiency to knee instability based on anterior cruciate ligament (ACL) deficiency, in the condition of a functional iliotibial band (ITB).

METHODS

Nine freshly-frozen cadaveric knees were sectioned sequentially to create ACL deficiency and ACL-ALS deficiency, using intact knees before sectioning as controls. When ITB was tensioned with 30 N, 4 separate aspects of knee instability were tested as follows: anterior translation in 90 N anterior load, isolated internal rotation in 5 N·m internal rotational torque from 0° to 90° in 15° increments, and anterolateral translation and internal rotation during a simulated pivot-shift test at 0°, 15°, 30°, and 45°. The contribution of ACL deficiency alone and additional ALS deficiency to knee instability were evaluated.

RESULTS

The addition of an ALS lesion produced no significant exacerbation of either anterior translational or pivot shift instability in ACL-deficient knees. Additional ALS deficiency in an ACL-deficient knee resulted in a significant increase in isolated internal rotation from 45° to 90° (P = .001 at 45° and P < .001 in other cases). After sequentially sectioning, the contribution to instability of additional ALS deficiency to the entire instability in ACL-ALS-deficient knees was significantly smaller than that of ACL deficiency alone during anterior load and pivot-shift test (P < .001 in all cases), but significantly contributed more to isolated internal rotational instability at 60° (P = .011) and 90° (P = .015).

CONCLUSIONS

When ITB was tensioned, ALS played a minor role in controlling both anterior or pivot shift stability in ACL-deficient knees but a major role in restraining isolated internal rotation from 45° to 90°.

CLINICAL RELEVANCE

In the condition of functional ITB, concomitant ALS injury might not exacerbate anterior and pivot-shift instability after ACL rupture, while affecting isolated internal rotation stability at higher flexion.

Lateral extra-articular tenodesis in patients with revision anterior cruciate ligament (ACL) reconstruction and high-grade anterior knee instability

BACKGROUND

Additional lateral extra-articular procedures can reduce the risk of failure of primary anterior cruciate ligament reconstruction (ACLR). There is limited evidence on the effect of lateral extra-articular procedures in revision ACL surgery. The purpose of this study was to evaluate the clinical outcome of patients with lateral extra-articular tenodesis (LET) in combination with revision ACLR for combined ACL graft failure and high-grade anterior knee instability.

METHODS

Between 2016 and 2018, 75 patients with graft failure after primary ACLR and high-grade anterior knee instability who received revision ACLR were included in the retrospective study. High-grade anterior knee instability was defined as high-grade pivot-shift or side-to-side difference of more than six millimeters in Rolimeter®-testing. An additional modified Lemaire tenodesis was performed in 59 patients during revision ACLR. Seventy-three patients were clinically examined with a minimum of two years after revision surgery.

RESULTS

Failure of the revision ACLR occurred in 8.2% (n = 6) of the cases. LET lead to significant decreased failure rates (five percent vs. 21%, p = .045) and decreased incidence of a positive pivot-shift in patients with revision ACLR and high-grade anterior knee instability in comparison to patients without LET. Also, postoperative functional scores were significantly increased in the group of additional LET.

CONCLUSIONS

Additional LET in patients with revision ACLR and high-grade anterior instability significantly reduces the risk of failure of revision ACLR, the incidence of pivot-shift and increases postoperative functional outcome.

Paediatric knee anterolateral capsule does not contain a distinct ligament: analysis of histology, immunohistochemistry and gene expression

OBJECTIVES

The presence of a discrete ligament within the knee anterolateral capsule (ALC) is controversial. Tendons and ligaments have typical collagens, ultrastructure, transcription factors and proteins. However, these characteristics have not been investigated in paediatric ALC. The purpose of this study was to characterise the paediatric ALC in terms of tissue ultrastructure and cellular expression of ligament markers scleraxis (SCX)-a basic helix-loop-helix transcription factor-and the downstream transmembrane glycoprotein tenomodulin (TNMD), as compared with the paediatric lateral collateral ligament (LCL) and paediatric quadriceps tendon (QT). We hypothesised that, in comparison to the LCL and QT, the ALC would possess poor collagen orientation and reduced SCX and TNMD expression.

METHODS

15 paediatric ALCs (age 6.3±3.3 years), 5 paediatric LCLs (age 3.4±1.3 years) and 5 paediatric QTs (age 2.0±1.2 years) from fresh cadaveric knees were used in this study. Fresh-frozen samples from each region were cryosectioned and then stained with H&E to evaluate collagen alignment and cell morphology. Expression of SCX and TNMD was determined by gene expression analysis and immunohistochemistry.

RESULTS

The histological sections of the paediatric LCL and QT showed well-organised, dense collagenous tissue fibres with elongated fibroblasts, while the ALC showed more random collagen orientation without clear cellular directionality. The aspect ratio of cells in the ALC was significantly lower than that of the LCL and QT (p<0.0001 and p<0.0001, respectively). The normalised distribution curve of the inclination angles of the nuclei in the ALC was more broadly distributed than that of the LCL or QT, indicating random cell alignment in the ALC. SCX immunostaining was apparent in the paediatric LCL within regions of aligned fibres, while the comparatively disorganised structure of the ALC was negative for SCX. The paediatric LCL also stained positive for TNMD, while the ALC was only sparsely positive for this tendon/ligament cell-surface molecule. Relative gene expression of SCX and TNMD were higher in the LCL and QT than in the ALC.

CONCLUSION

In this study, a distinct ligament could not be discerned in the ALC based on histology, immunohistochemistry and gene expression analysis.

LEVEL OF EVIDENCE

Controlled laboratory study.

Visualization of Proximal and Distal Kaplan Fibers Using 3-Dimensional Magnetic Resonance Imaging and Anatomic Dissection

BACKGROUND

In current magnetic resonance imaging (MRI) of the knee, injuries to the anterolateral ligament complex (ALC) and the Kaplan fibers (KFs) are not routinely assessed. As ruptures of the KFs contribute to anterolateral rotatory instability in the anterior cruciate ligament-deficient knee, detecting these injuries on MRI may help surgeons to individualize treatment.

PURPOSE

To visualize the KFs on 3-T MRI and to conduct a layer-by-layer dissection of the ALC.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Ten fresh-frozen human cadaveric knees (mean ± SD age, 72 ± 8.5 years) without history of ligament injury were used in this study. Before layer-by-layer dissection of the ALC, MRI was performed to define the radiologic anatomy of the KFs. A coronal T1-weighted 3-dimensional turbo spin echo sequence and a transverse T2-weighted turbo spin echo sequence were obtained. Three-dimensional data sets were used for multiplanar reconstructions.

RESULTS

KFs were identified in 100% of cases on MRI and in anatomic dissection. The mean length of the proximal and distal KFs was 17.9 ± 3.6 mm and 12.4 ± 6.5 mm, respectively. On MRI, the distance from the lateral femoral epicondyle to the proximal KFs was 35.9 ± 6.9 mm and to the distal KFs, 16.6 ± 4.1 mm; in anatomic dissection, the distances were 41.4 ± 8.1 mm for proximal KFs and 28.2 ± 8.1 mm for distal KFs. The distance from the lateral joint line to the proximal KFs was 63.5 ± 7.6 mm and to the distal KFs, 45.3 ± 3.7 mm. Interobserver reliability for image analysis was excellent for all measurements.

CONCLUSION

KFs can be consistently identified on MRI with use of 3-dimensional sequences. Subsequent anatomic dissection confirmed their close topography to the superior lateral genicular artery. For clinical implications, the integrity of the KFs should be routinely reviewed on MRI scans.

CLINICAL RELEVANCE

As ruptures of the KFs contribute to anterolateral rotatory instability, accurate visualization of the KFs on MRI may facilitate surgical decision making for additional anterolateral procedures in the anterior cruciate ligament-deficient knee.

A fluoroscopic analysis of the length changes of the capsulo-osseous layer of the distal iliotibial band

PURPOSE

Previous studies have implicated the iliotibial band and its deeper capsulo-osseous layer as key restraints against internal rotation. However, the kinematic properties of the capsulo-osseous layer, throughout knee range of motion, are not currently known. Therefore, the purpose of this research was to quantify the length changes of this structure through various degrees of knee flexion.

METHODS

Ten cadaveric knee specimens were dissected to expose the capsulo-osseous layer of the iliotibial band. Radiopaque beads were embedded, at standardized increments, into the tissue and fluoroscopic images were taken from 0° to 105° of knee flexion in 15° increments. The positions of the beads were identified in each image and the length, width, and area changes of the capsulo-osseous layer were calculated. The data were analyzed as a percent change from 0° and compared across flexion angles using a repeated-measures analysis of variance (α = 0.05).

RESULTS

There was a significant increase in the length of the capsulo-osseous layer at flexion angles greater than 30°, with changes occurring primarily at the level of the femoral insertion. Meanwhile, non-homogenous decreases in width and area were found with increasing flexion angle. The distance between the capsulo-osseous layer insertion on the distal femur and proximal tibia significantly increased from 60° to 105°; maximal changes occurred at 105° [9.64 (4.12) %, p = 0.003].

CONCLUSIONS

The capsulo-osseous layer of the iliotibial band behaves in a non-isometric fashion and this work suggests that tensioning and fixation should occur between 75° and 105° of flexion, if repair or reconstruction is indicated.

Lateral Extra-articular Tenodesis Reduces Failure of Hamstring Tendon Autograft Anterior Cruciate Ligament Reconstruction: 2-Year Outcomes From the STABILITY Study Randomized Clinical Trial

BACKGROUND

Persistent anterolateral rotatory laxity after anterior cruciate ligament (ACL) reconstruction (ACLR) has been correlated with poor clinical outcomes and graft failure.

HYPOTHESIS

We hypothesized that a single-bundle, hamstring ACLR in combination with a lateral extra-articular tenodesis (LET) would reduce the risk of ACLR failure in young, active individuals.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

This is a multicenter, prospective, randomized clinical trial comparing a single-bundle, hamstring tendon ACLR with or without LET performed using a strip of iliotibial band. Patients 25 years or younger with an ACL-deficient knee were included and also had to meet at least 2 of the following 3 criteria: (1) grade 2 pivot shift or greater, (2) a desire to return to high-risk/pivoting sports, (3) and generalized ligamentous laxity (GLL). The primary outcome was ACLR clinical failure, a composite measure of rotatory laxity or a graft rupture. Secondary outcome measures included the P4 pain scale, Marx Activity Rating Scale, Knee injury Osteoarthritis and Outcome Score (KOOS), International Knee Documentation Committee score, and ACL Quality of Life Questionnaire. Patients were reviewed at 3, 6, 12, and 24 months postoperatively.

RESULTS

A total of 618 patients (297 males; 48%) with a mean age of 18.9 years (range, 14-25 years) were randomized. A total of 436 (87.9%) patients presented preoperatively with high-grade rotatory laxity (grade 2 pivot shift or greater), and 215 (42.1%) were diagnosed as having GLL. There were 18 patients lost to follow-up and 11 who withdrew (~5%). In the ACLR group, 120/298 (40%) patients sustained the primary outcome of clinical failure, compared with 72/291 (25%) in the ACLR+LET group (relative risk reduction [RRR], 0.38; 95% CI, 0.21-0.52; P < .0001). A total of 45 patients experienced graft rupture, 34/298 (11%) in the ACLR group compared with 11/291 (4%) in the ACL+LET group (RRR, 0.67; 95% CI, 0.36-0.83; P < .001). The number needed to treat with LET to prevent 1 patient from graft rupture was 14.3 over the first 2 postoperative years. At 3 months, patients in the ACLR group had less pain as measured by the P4 (P = .003) and KOOS (P = .007), with KOOS pain persisting in favor of the ACLR group to 6 months (P = .02). No clinically important differences in patient-reported outcome measures were found between groups at other time points. The level of sports activity was similar between groups at 2 years after surgery, as measured by the Marx Activity Rating Scale (P = .11).

CONCLUSION

The addition of LET to a single-bundle hamstring tendon autograft ACLR in young patients at high risk of failure results in a statistically significant, clinically relevant reduction in graft rupture and persistent rotatory laxity at 2 years after surgery.

REGISTRATION

NCT02018354 ( ClinicalTrials.gov identifier).

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 Anterolateral Structure of the Knee Does Not Affect Anterior and Dynamic Rotatory Stability in Anterior Cruciate Ligament Injury: Quantitative Evaluation With the Electromagnetic Measurement System

BACKGROUND

The biomechanical function of the anterolateral structure (ALS), which includes the anterolateral joint capsule and anterolateral ligament (ALL), remains a topic of debate.

HYPOTHESIS

The ALS contributes to knee joint stability during the Lachman test and the pivot-shift test in anterior cruciate ligament (ACL)-deficient knees.

STUDY DESIGN

Controlled laboratory study.

METHODS

Fourteen fresh-frozen hemipelvis lower limbs were used. For 7 specimens, the anterior one-third of the ALS and the residual ALS were cut intra-articularly with a radiofrequency device. Subsequently, the ACL was cut arthroscopically. For the other 7 specimens, the ACL was cut first, followed by the anterior one-third of the ALS and the residual ALS intra-articularly. During the procedures, the iliotibial band (ITB) was kept intact. At each condition, the anterior tibial translation (ATT) during the manual Lachman test and the acceleration of posterior tibial translation (APT) and the posterior tibial translation (PTT) during the manual pivot-shift test were measured quantitatively with an electromagnetic measurement system. The mean values of those parameters were compared among 6 groups (ACL intact, one-third ALS cut, all ALS cut, ACL cut, ACL/one-third ALS cut, and ACL/all ALS cut).

RESULTS

The mean ATTs during the Lachman test and the mean APTs and PTTs in the ACL-cut conditions (ACL cut, ACL/one-third ALS cut, and ACL/all ALS cut) were significantly larger than those under the ACL-intact conditions (ACL intact, one-third ALS cut, all ALS cut) (P < .01). However, no statistically significant differences were observed among the intact, one-third ALS-cut, and all ALS-cut conditions, within the ACL-intact or ACL-cut conditions.

CONCLUSION

Intra-articular dissection of the ALS did not increase the ATT during the Lachman test or the APT and PTT during the pivot-shift test under the intact condition of the ITB, regardless of the integrity of the ACL. When the ITB is intact, the ALS does not have a significant role in either anterior or dynamic rotatory knee stability, while the ACL does.

CLINICAL RELEVANCE

Recent growing interest about ALL reconstruction or ALS augmentation may not have a large role in controlling either anterior or dynamic rotatory knee instability in isolated ACL-deficient knees.

Biomechanical Assessment of a Distally Fixed Lateral Extra-articular Augmentation Procedure in the Treatment of Anterolateral Rotational Laxity of the Knee

BACKGROUND

Most lateral extra-articular tenodesis (LET) procedures rely on passing a strip of the iliotibial band (ITB) under the fibular (lateral) collateral ligament and fixing it proximally to the femur. The Ellison procedure is a distally fixed lateral extra-articular augmentation procedure with no proximal fixation of the ITB. It has the potential advantages of maintaining a dynamic element of control of knee rotation and avoiding the possibility of overconstraint.

HYPOTHESIS

The modified Ellison procedure would restore native knee kinematics after sectioning of the anterolateral capsule, and closure of the ITB defect would decrease rotational laxity of the knee.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twelve fresh-frozen cadaveric knees were tested in a 6 degrees of freedom robotic system through 0° to 90° of knee flexion to assess anteroposterior, internal rotation (IR), and external rotation laxities. A simulated pivot shift (SPS) was performed at 0°, 15°, 30°, and 45° of flexion. Kinematic testing was performed in the intact knee and anterolateral capsule-injured knee and after the modified Ellison procedure, with and without closure of the ITB defect. A novel pulley system was used to load the ITB at 30 N for all testing states. Statistical analysis used repeated measures analyses of variance and paired t tests with Bonferroni adjustments.

RESULTS

Sectioning of the anterolateral capsule increased anterior drawer and IR during isolated displacement and with the SPS (mean increase, 2° of IR; P < .05). The modified Ellison procedure reduced both isolated and coupled IR as compared with the sectioned state (P < .05). During isolated testing, IR was reduced close to that of the intact state with the modified Ellison procedure, except at 30° of knee flexion, when it was slightly overconstrained. During the SPS, IR with the closed modified Ellison was less than that in the intact state at 15° and 30° of flexion. No significant differences in knee kinematics were seen between the ITB defect open and closed.

CONCLUSION

A distally fixed lateral augmentation procedure can closely restore knee laxities to native values in an anterolateral capsule-sectioned knee. Although the modified Ellison did result in overconstraint to isolated IR and coupled IR during SPS, this occurred only in the early range of knee flexion. Closure of the ITB defect had no effect on knee kinematics.

CLINICAL RELEVANCE

A distally fixed lateral extra-articular augmentation procedure provides an alternative to a proximally fixed LET and can reduce anterolateral laxity in the anterolateral capsule-injured knee and restore kinematics close to the intact state.

High Prevalence of Anterolateral Ligament Abnormalities on MRI in Knees With Acute Anterior Cruciate Ligament Injuries: A Case-Control Series From the SANTI Study Group

Background:

Broad variation in the reported rate of magnetic resonance imaging (MRI)–detected abnormalities of the anterolateral structures of the anterior cruciate ligament (ACL)–injured knee suggests a lack of reliability that has limited the use of MRI in clinical decision making.

Purpose/Hypothesis:

The aim of this study was to use MRI to determine the prevalence and spectrum of abnormalities of the anterolateral structures in acute ACL-injured knees, using the contralateral uninjured knee as a reference. We hypothesized that MRI evaluation of the acutely injured knee (using the uninjured knee as a reference) would allow reliable identification of abnormalities of the anterolateral structures.

Study Design:

Cohort study (diagnosis); Level of evidence, 3.

Methods:

Patients with acute ACL injury underwent MRI scan of both knees. Images were evaluated by 3 observers. Inter- and intraobserver reliabilities were determined for MRI parameters of anterolateral ligament (ALL) injury by use of the kappa (κ) test. Univariate and multivariate analyses were conducted to test associations between ALL abnormality and associated injuries.

Results:

A total of 34 patients were evaluated. Of these, 30 patients (88.2%) had at least 1 ALL abnormality in the ACL-injured knee (increased signal: n = 27[79.4%]; increased thickness: n = 15[44.1%]; tapering: n = 7[20.6%]; irregularities in the path of the ALL fibers: n = 21[61.7%]). Asymmetries of the genicular vessels were observed in 21 patients (61.7%). ALL abnormality was significantly associated with lateral joint capsular tears (P < .001). No correlation was found between ALL lesions and iliotibial band lesions (P = .49). Inter- and intraobserver reliabilities were very good concerning ALL signal changes and femoral and tibial bone bruises (κ coefficient, 0.81-1).

Conclusion:

MRI evaluation of the ALL was associated with good and very good inter- and intraobserver reliabilities, and it demonstrated abnormalities of the ALL in the majority of acutely ACL-injured knees. The index of suspicion for ALL injury should be elevated by the presence of lesions of the lateral capsule. This suggests that the ALL is part of a wider area of the lateral capsule that is often injured simultaneously in an acute ACL tear.

The anatomy of the anterolateral structures of the knee - A histologic and macroscopic approach

BACKGROUND

The anatomy of the anterolateral structures of the knee is complex and still controversial. The aim of our study was to analyze this anatomy by histologic and macroscopic evaluation, with a particular emphasis on the anterolateral ligament (ALL).

MATERIAL AND METHODS

Twenty-three cadaveric knee joints were dissected followed by a qualitative and quantitative anatomic analysis of the anterolateral knee structures. Histology and comparison of different anterolateral structures was performed in addition.

RESULTS

The ALL was identified in all of the dissected cadaveric knee specimens. It runs in an oblique course from its proximo-dorsal insertion at the distal femur into a ventro-distal direction to the anterolateral tibia. The femoral insertion site was found to be posterior and slightly proximal to the lateral femoral epicondyle and the femoral attachment of the lateral collateral ligament (LCL). The femoral insertion of the ALL overlapped the LCL in all dissected knees. The tibial insertion site was midway between Gerdy's tubercle (GT) and the tip of the fibular head (FH). In 15 of the dissected 23 knee joints, thin attachments to the lateral meniscus were observed. Histology confirmed differences in the composition of the anterolateral knee joint capsule, the ALL and the iliotibial band (ITB).

CONCLUSIONS

The ALL occurs as a regular separate anterolateral ligamentous structure. It is distinguishable from the ITB and the anterolateral joint capsule in both embalmed and non-embalmed specimens. Histology of the ALL indicates typical ligamentous tissue which clearly differs from the anterolateral knee joint capsule and the thicker ITB.

LEVEL OF EVIDENCE

Level II, descriptive anatomic study.

The Stability study: a protocol for a multicenter randomized clinical trial comparing anterior cruciate ligament reconstruction with and without Lateral Extra-articular Tenodesis in individuals who are at high risk of graft failure

Background

The purpose of anterior cruciate ligament reconstruction (ACLR) is to restore stability to the knee. Persistent rotational laxity following ACLR has been correlated with poor outcome and graft failure. We hypothesize that anterolateral complex reconstruction by way of a Modified Lemaire Lateral Extra-articular Tenodesis (LET) in combination with single bundle ACLR would reduce the risk of persistent rotatory laxity in young individuals who are deemed as being at high risk of failure. We will conduct a pragmatic, multicenter, randomized clinical trial comparing standard single bundle hamstring ACLR with combined ACLR and LET.

Methods

Six-hundred patients (300 per group) aged 25 years or less with an ACL deficient knee that meet two of the following three criteria will be included: 1) Grade 2 pivot shift or greater; 2) Returning to high risk cutting or pivoting sports; 3) Generalized ligamentous laxity. Participants will be seen at 3-months, 6-months, 12-months and 24-months post-operatively. The primary outcome measure is graft failure requiring revision ACLR or symptomatic instability associated with a positive asymmetric pivot shift indicating persistent rotational laxity. Patients will complete secondary outcome measures at each follow-up visit including patient-reported outcome measures, functional and biomechanical testing, and magnetic resonance imaging.

Discussion

This protocol is the first adequately powered randomized clinical trial investigating the effects of augmenting ACLR with an LET in patients at high-risk of graft failure. The successful completion of this trial has the potential to change surgical practice and provide evidence for the role of the LET in ACLR.

Trial registration

The trial is registered at ClinicalTrials.gov: NCT02018354, 23-12-2013.

Editorial Commentary: Magnetic Resonance Imaging of the Knee Anterolateral Ligament: Does It Really Matter?

Great interest remains in the structures of the knee anterolateral complex and how they work synergistically with the anterior cruciate ligament to control anterolateral rotatory laxity. Many studies have now used magnetic resonance imaging to assess the degree of damage to the anterolateral ligament. The systematic review described in this commentary rigorously highlights the many deficiencies that exist within our current understanding of the imaging analysis of these structures. Marked variability in the definition of anterolateral ligament injury, significant methodological differences, and the lack of a gold standard reference make it very challenging to translate the findings of these imaging studies into clinical practice. More information is required to fully understand the injury pattern, and then clinical studies are needed to guide treatment. Hopefully we will then have the ability to better treat our patients with these challenging complex laxity patterns that exist over and above an isolated anterior cruciate ligament injury.

Anatomical Consideration of the Anterolateral Ligament of the Knee

Many researchers have studied the structures of the anterolateral part of the knee. Several researchers have investigated the existence of the anterolateral ligament (ALL) and its frequency has been inconsistently reported. Therefore, we assessed whether the ALL is the anatomical true ligament and studied the morphological variations of this structure. Sixty-four Korean adult cadavers (120 knees, mean age: 79.1 years) were used for this study. The lateral part of the knee joint was carefully dissected with internal rotation of the tibia. We checked the existence and morphological features and measured the dimensions (length, width, and thickness) of the ALL. The ALL was clearly distinguished from the capsulo-osseous layer of the iliotibial tract and runs obliquely from the lateral femoral epicondyle to the tibial plateau. The ALL was found in 42.5% of the samples, and 15 cadavers had ALLs in both knees. There was no prevalence difference between females and males. Most of the anterior border of the ALL was blended with the knee capsule. Therefore, we concluded that this structure is a local thickening of the capsule in the anterolateral region of the knee, where it possibly developed against some external physical stress. Therefore, the ALLs in this present study can be defined as a capsular ligament of the knee and, as per the nomenclature of the capsular ligament, can be also called the ‘anterolateral (capsular) ligament'.

Assessment of Anterolateral Complex Injuries by Magnetic Resonance Imaging in Patients With Acute Rupture of the Anterior Cruciate Ligament

PURPOSE

To assess anterolateral complex (ALC) injuries in patients with acute anterior cruciate ligament (ACL) rupture on magnetic resonance imaging (MRI).

METHODS

Patients with acute ACL rupture who underwent ACL surgery between 2015 and 2017 and underwent MRI within 6 weeks of the initial trauma were included. Two radiologists assessed magnetic resonance images retrospectively for the status of the ALC, including the iliotibial band (ITB), Kaplan fibers, and anterolateral ligament (ALL), as follows: grade 0, normal; grade 1, periligamentous edema; grade 2, partial tear; and grade 3, complete tear. The findings were analyzed using the Friedman test and weighted κ values.

RESULTS

Sixty-nine MRI scans were reviewed. Of the 69 patients, 51% had associated injuries to the ITB (grade 1, n = 31; grade 2, n = 4), 33% had associated injuries to the Kaplan fibers (grade 1, n = 21; grade 2, n = 2), and 57% had associated injuries to the ALL (grade 1, n = 12; grade 2, n = 22; grade 3, n = 5). We found a significant difference in the frequency and grading between ITB, Kaplan fiber, and ALL injuries (P ≤ .032). Inter-reader agreement for assessing the ALC on MRI was almost perfect (κ ≥ 0.922).

CONCLUSIONS

On the basis of MRI analysis, ALL injuries were found with varying degrees of severity and intensity with noted injuries to associated surrounding fibers in patients with acute ACL rupture.

LEVEL OF EVIDENCE

Level IV, case series.

Anatomic Study and Reanalysis of the Nomenclature of the Anterolateral Complex of the Knee Focusing on the Distal Iliotibial Band: Identification and Description of the Condylar Strap

Background

The capsulo-osseous layer (COL), short lateral ligament, mid-third lateral capsular ligament, lateral capsular ligament, and anterolateral ligament (ALL) are terms that have been used interchangeably to describe what is probably the same structure. This has resulted in confusion regarding the anatomy and function of the anterolateral complex of the knee and its relation to the distal iliotibial band (ITB).

Purpose

To characterize the macroscopic anatomy of the anterolateral complex of the knee, in particular the femoral condylar attachment of the distal ITB. We identified a specific and consistent anatomic structure that has not been accurately described previously; it connects the deep surface of the ITB to the condylar area and is distinct from the ALL, COL, and Kaplan fibers.

Study Design

Descriptive laboratory study.

Methods

Sixteen fresh-frozen human cadaveric knees were used to study the anterolateral complex of the knee. Standardized dissections were performed that included qualitative and quantitative assessments of the anatomy through both anterior (n = 5) and posterior (n = 11) approaches.

Results

The femoral condylar attachment of the distal ITB was not reliably identified by anterior dissection but was in all posterior dissections. A distinct anatomic structure, hereafter termed the "condylar strap" (CS), was identified between the femur and the lateral gastrocnemius on one side and the deep surface of the ITB on the other, in all posteriorly dissected specimens. The structure had a mean thickness of 0.88 mm, and its femoral insertion was located between the distal Kaplan fibers and the epicondyle. The proximal femoral attachment of the structure had a mean width of 15.82 mm, and the width of the distal insertion of the structure on the ITB was 13.27 mm. The mean length of the structure was 26.33 mm on its distal border and 21.88 mm on its proximal border. The qualitative evaluation of behavior in internal rotation revealed that this anatomic structure became tensioned and created a tenodesis effect on the ITB.

Conclusion

There is a consistent structure that attaches to the deep ITB and the femoral epicondylar area. The orientation of fibers suggests that it may have a role in anterolateral knee stability.

Clinical Relevance

This new anatomic description may help surgeons to optimize technical aspects of lateral extra-articular procedures in cases of anterolateral knee laxity.

The anterolateral complex of the knee: results from the International ALC Consensus Group Meeting

The structure and function of the anterolateral complex (ALC) of the knee has created much controversy since the 're-discovery' of the anterolateral ligament (ALL) and its proposed role in aiding control of anterolateral rotatory laxity in the anterior cruciate ligament (ACL) injured knee. A group of surgeons and researchers prominent in the field gathered to produce consensus as to the anatomy and biomechanical properties of the ALC. The evidence for and against utilisation of ALC reconstruction was also discussed, generating a number of consensus statements by following a modified Delphi process. Key points include that the ALC consists of the superficial and deep aspects of the iliotibial tract with its Kaplan fibre attachments on the distal femur, along with the ALL, a capsular structure within the anterolateral capsule. A number of structures attach to the area of the Segond fracture including the capsule-osseous layer of the iliotibial band, the ALL and the anterior arm of the short head of biceps, and hence it is not clear which is responsible for this lesion. The ALC functions to provide anterolateral rotatory stability as a secondary stabiliser to the ACL. Whilst biomechanical studies have shown that these structures play an important role in controlling stability at the time of ACL reconstruction, the optimal surgical procedure has not yet been defined clinically. Concern remains that these procedures may cause constraint of motion, yet no clinical studies have demonstrated an increased risk of osteoarthritis development. Furthermore, clinical evidence is currently lacking to support clear indications for lateral extra-articular procedures as an augmentation to ACL reconstruction. The resulting statements and scientific rationale aim to inform readers on the most current thinking and identify areas of needed basic science and clinical research to help improve patient outcomes following ACL injury and subsequent reconstruction.Level of evidence V.

[Modified Lemaire Procedure: Indication, procedure, and clinical results]

BACKGROUND

The mechanisms of anterior cruciate ligament (ACR) rupture may include a pivoting mechanism, which is responsible for concomitant lesions of the anterolateral structures. This anterolateral complex is the main stabilizer of tibial internal rotation and therefore accountable for a persisting pivot shift despite technical improvement of ACR reconstruction. For this reason, knee surgeons' interest in addressing anterolateral stabilization in addition to ACR reconstruction has been renewed.

STUDIES

Biomechanical and clinical studies have shown promising results so far. The modified, lateral, extra-articular stabilization according to Lemaire as a non-anatomical reconstruction of the anterolateral ligament (ALL) shines with a low morbidity, since no additional tendon harvesting is needed. Besides the potential benefits there are several risks and disadvantages. For example, complete control of the pivot-shift phenomenon is not possible in nearly 8% of cases. In addition, too tight tensioning of the ALL may result in an increase of pressure in the lateral knee compartment. Overall, ALL reconstruction is a hot topic and is heavily discussed in literature. This article provides an overview and brings the modified technique of Lemaire into focus.

Combined reconstruction of the anterolateral ligament in chronic ACL injuries leads to better clinical outcomes than isolated ACL reconstruction

PURPOSE

To evaluate the results of combined anterior cruciate ligament (ACL) and anterolateral ligament (ALL) reconstruction in patients with chronic ACL injury. It was hypothesized that patients who underwent combined ACL and ALL reconstruction would exhibit less residual laxity and better clinical outcomes.

METHODS

Two groups of patients were evaluated and compared retrospectively. Both groups consisted only of patients with chronic (more than 12 months) ACL injuries. Patients in group 1 underwent anatomical intra-articular reconstruction of the ACL and patients in group 2 underwent anatomic intra-articular ACL reconstruction combined with ALL reconstruction. The presence of associated meniscal injury, the subjective International Knee Documentation Committee (IKDC) and Lysholm functional outcome scores in the postoperative period, KT-1000 evaluation, the presence of residual pivot shift and graft rupture rate were evaluated.

RESULTS

One hundred and one patients who underwent reconstruction of chronic ACL injuries were evaluated. The median follow-up was 26 (24-29) months for group 1 and 25 (24-28) months for group 2. There were no significant differences between groups regarding gender, age, duration of injury until reconstruction, follow-up time or presence of associated meniscal injuries in the preoperative period. Regarding functional outcome scores, patients in group 2 presented better results on both the IKDC (p = 0.0013) and the Lysholm (p < 0.0001) evaluations. In addition, patients in group 2 had better KT-1000 evaluation (p = 0.048) and a lower pivot shift rate at physical examination, presenting only 9.1% positivity versus 35.3% in the isolated ACL reconstruction (p = 0.011). Regarding re-ruptures, group 1 presented 5 (7.3%) cases, and group 2 presented no cases.

CONCLUSION

The combined ACL and ALL reconstruction in patients with chronic ACL injury is an effective and safety solution and leads to good functional outcomes with no increase in complication rate. The clinical relevance of this finding is the possibility to indicate this type of procedure when patients present with more than 12 months after injury for surgery.

LEVEL OF EVIDENCE

Level III.

There Are No Kinematic Differences Between Inframeniscal and Suprameniscal Anterolateral Ligament Injury in the Anterior Cruciate Ligament-Deficient Knee

BACKGROUND

Previous research demonstrated that the attachment of the anterolateral ligament (ALL) to the lateral meniscus is stiffer and stronger in its tibial attachment than its femoral attachment. How this relates to anterolateral knee stability and lateral meniscal function is unknown.

HYPOTHESIS/PURPOSE

The hypothesis was that the ALL acts as a peripheral anchor to the lateral meniscus, aiding in anterolateral rotatory stability, and that the inframeniscal fibers of the ALL will provide greater anterolateral rotatory stability because of their greater tensile properties. The purpose was therefore to compare the difference in kinematics of the anterior cruciate ligament (ACL)-deficient knee between the infra- and suprameniscal ALL-sectioned states.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight paired fresh-frozen cadaveric knees were tested in a 5-degree of freedom loading jig under the following loading conditions: 5-N·m internal rotation at 15° incremental angles of flexion and combined 5-N·m internal rotation moment, 10-N·m valgus moment, and 88-N anterior translation force representing a pivot shift test at 0°, 15°, and 30° of flexion. The knees were tested under intact, ACL-deficient, and ACL-/ALL-deficient conditions, with the pairs of knees being randomized to either supra- or inframeniscal ALL sectioning. Resultant joint kinematics and tibiofemoral translations were measured and compared with a 2-way mixed repeated measures analysis of variance.

RESULTS

Internal rotation increased by 3° after sectioning of the ACL at 0° of knee flexion ( P = .035). At 45° of knee flexion, internal rotation increased significantly by 2° between the ACL-deficient and the ACL-/ALL-deficient conditions ( P = .049). Secondary kinematics of valgus and anterior translation were observed in response to the 5-N·m load after ACL and ALL sectioning. Analysis of the pivot shift showed increases in tibiofemoral translation after sectioning of the ACL, with further translations after sectioning of the ALL. No differences were observed between supra- and inframeniscal ALL sectioning under any of the loading conditions.

CONCLUSION

An injury to the ALL, coexisting with ACL deficiency, results in only minor increases in knee joint patholaxity. No differences in pivot-shift kinematics or tibiofemoral rotations were observed between the supra- and inframeniscal sectioning of the ALL in the ACL-deficient knee.

CLINICAL RELEVANCE

Tears of the midbody and/or posterior root attachment of the lateral meniscus are often observed at the time of ACL reconstruction. Increased anterolateral rotatory laxity has been observed in both lateral meniscus- and ALL-deficient states in combination with an ACL injury. While no significant functional relationship was found between the ALL and lateral meniscus, ALL sectioning did result in increased knee joint patholaxity, as demonstrated by composite tibiofemoral rotations.

Revision Anterior Cruciate Ligament Reconstruction With Hamstrings and Extra-articular Tenodesis: A Mid- to Long-Term Clinical and Radiological Study

PURPOSE

To present the mid- to long-term clinical and radiographic outcomes of a series of patients who underwent revision anterior cruciate ligament (ACL) reconstruction with doubled gracilis and semitendinosus (DGST) autograft and a lateral extra-articular tenodesis (LET).

METHODS

Patients who underwent revision ACL reconstruction with DGST and LET by a single surgeon between January 1997 and December 2013 were included. Revision was indicated by ACL failure noted on magnetic resonance imaging, persistent clinical instability, or laxity on clinical exam. Patients were evaluated preoperatively and at latest follow-up by an independent board-certified orthopaedic surgeon. Outcomes included Lachman and pivot shift tests, validated clinical and patient reported outcomes scores, and radiographic analysis. The presence of previous meniscectomy or chondral injury was recorded intraoperatively.

RESULTS

A total of 118/132 potential patients (89.4%) was available for follow-up at a mean 10.6 years (3-19 years) postoperatively. Lachman and pivot shift examinations as well as the side-to-side difference on an KT-1000 arthrometer demonstrated significant improvement at latest follow-up (P < .05) versus preoperative evaluation. Severe degenerative disease was present in 25% of patients on radiograph and correlated with worsened clinical outcomes. Previous meniscectomy was the only risk factor analyzed that correlated with worsened radiographic grade. No patients had a graft tear based on clinical and/or magnetic resonance imaging evaluation, but 9 (7.6%) failed based on a side-to-side difference of >5 mm on the KT-1000, a grade ≥2+ on pivot shift, or report of continued instability.

CONCLUSIONS

Revision ACL reconstruction with DGST and LET at mid- to long-term follow-up provides continued improvement in clinical and radiological outcomes from preoperative assessment. Meniscectomy was the only factor related to worsened radiological grades and clinical outcomes.

LEVEL OF EVIDENCE

Level IV, case series.

Anatomic and Histological Study of the Anterolateral Aspect of the Knee: A SANTI Group Investigation

Background:

The structure and function of the anterolateral aspect of the knee have been significantly debated, with renewed interest in this topic since the description of the anterolateral ligament (ALL).

Purpose:

To define and describe the distinct structures of the lateral knee and to correlate the macroscopic and histologic anatomic features.

Study Design:

Descriptive laboratory study.

Methods:

Twelve fresh-frozen human cadavers were used for anatomic analysis. In the left knee, a layer-by-layer dissection and macroscopic analysis were performed. In the right knee, an en bloc specimen was obtained encompassing an area from the Gerdy tubercle to the posterior fibular head and extending proximally from the anterior aspect to the posterior aspect of the lateral femoral epicondyle. The en bloc resection was then frozen, sliced at the level of the joint line, and reviewed by a musculoskeletal pathologist.

Results:

Macroscopically, the lateral knee has 4 main layers overlying the capsule of the knee: the aponeurotic layer, the superficial layer including the iliotibial band (ITB), the deep fascial layer, and the ALL. Histologically, 8 of 12 specimens demonstrated 4 consistent, distinct structures: the ITB, the ALL, the lateral collateral ligament, and the meniscus.

Conclusion:

The lateral knee has a complex orientation of layers and fibers. The ALL is a distinct structure from the ITB and is synonymous to the previously described capsulo-osseous layer of the ITB.

Clinical Relevance:

Increasingly, lateral extra-articular procedures are performed at the time of anterior cruciate ligament reconstruction. Understanding the anatomic features of the anterolateral aspect of the knee is necessary to understand the biomechanics and function of the structures present and allows surgeons to attempt to replicate those anatomic characteristics when performing extra-articular reconstruction.

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

Background

Diffuse 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 presentation

Here, 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.

Conclusions

Extra-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.

The anterolateral ligament is a distinct ligamentous structure: A histological explanation

BACKGROUND

The aim was to determine whether the anterolateral ligament (ALL) had a histological structure that defined it as a real ligament.

METHODS

Histological examination of 30 ALL samples taken from fresh-frozen knees were performed. The ALL femoral insertion and its relationship with the lateral collateral ligament (LCL) were studied and the tibial insertion and its relationship with articular cartilage of the tibial joint surface were analyzed. For the ligamentous part, its histological structure and its differences with the articular capsule were studied.

RESULTS

This connective tissue is composed of a dense fibrous core constituted by a network of oriented collagenous fibers. The periphery of this dense connective center is made up of loose fibrocollagenous tissue with vascular structures and focal deposits of adipose tissue. This part was in contact but different to the joint capsule. With a perpendicular orientation of the collagen fibers relative to the bone, a fibrocartilaginous zone with an unmineralized hyalinized aspect, a mineralization front, its bone insertions presented a typical ligamentous insertion. With a cleavage plane between ALL and LCL femoral insertion, the ALL appeared to have a femoral insertion distinct from the LCL. ALL tibial insertion was less characteristic with less organized connective tissue and was at a distance from the articular cartilage.

CONCLUSION

From its bony insertion to its tissue composition and organization, the ALL has all the histological characteristics of a ligamentous structure. Our study confirms that ALL can be considered a real and distinct ligament.