Length change patterns in the lateral extra-articular structures of the knee and related reconstructions

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.

Higher contact pressure of the lateral tibiofemoral joint in lateral extra-articular tenodesis with tensioned graft in external rotation than in neutral rotation: A biomechanical study

OBJECTIVE

To determine the mean contact pressure, peak contact pressure, and mean contact area of the lateral tibiofemoral joint in lateral extra-articular tenodesis (LET) with tension on the graft in tibial neutral and external rotation.

METHODS

A total of eight Thiel-embalmed cadaveric knees were prepared and divided into two groups (4 knees in each group): the LET-NR group (lateral extra-articular tenodesis tension in neutral rotation) and (2) the LET-ER group (lateral extra-articular tenodesis tension in external rotation). Each knee was prepared according to the corresponding technique. A hydraulic testing system (E10000, Instron) simulates an axial load of 735 ​N for 10 ​s in each group.

RESULTS

The LET-ER group exhibited a statistically significant higher peak contact pressure compared to the LET-NR group. The peak contact pressure values in the LET-NR and LET-ER groups were 702.3 ​± ​233.9 ​kPa and 1235.5 ​± ​171.4 ​kPa, respectively (p ​= ​0.010, 95% CI, -888.0 to -178.5). The mean contact pressure values in the LET-NR and LET-ER groups were 344.9 ​± ​69.0 ​kPa and 355.3 ​± ​34.9 ​kPa, respectively (p ​= ​0.796, 95% CI, -105.1-84.2). The mean contact area values in the LET-NR and LET-ER groups were 36.8 ​± ​3.1 mm2 and 33.3 ​± ​6.4 mm2, respectively (p ​= ​0.360, 95% CI, -5.2-12.2).

CONCLUSIONS

The peak contact pressure of the lateral tibiofemoral joint is greater in LET when the graft is tensioned in external rotation than in neutral rotation. However, no statistically significant difference in the mean contact pressure or the mean contact area was observed between the two groups.

LEVEL OF EVIDENCE

III.

Description of the Anterior Cruciate Ligament Reconstruction Technique with Mini-Lemaire Type Anterolateral Tenodesis through a Single Femoral Tunnel

The anterior cruciate ligament (ACL) injury causes anteroposterior and rotational instability in the knee. Intra-articular reconstructions often fail to achieve satisfactory rotational control, leading to persistent complaints of instability and subjecting the neo-ligament to increased stress. Young patients with high athletic demands and grade 2 or 3 pivot-shift often have a higher risk of re-rupture after isolated ACL reconstruction. Over the years, various techniques have been developed to address such situations. Among the described techniques, one of the most commonly used is the modified or "mini-Lemaire" lateral extra-articular tenodesis. Biomechanical studies demonstrate the versatility of the technique due to its relatively isometric behavior in flexion angles of 0-60° when the graft is introduced deeply to the lateral collateral ligament. It offers the possibility of fixation at different anatomical positions on the lateral femoral condyle and at different degrees of flexion. The objective of this study is to describe an accessible, reproducible technique that relies on materials widely available in our environment.

Noninvasive and Reliable Quantification of Anteromedial Rotatory Knee Laxity: A Pilot Study on Healthy Individuals

BACKGROUND

Anteromedial rotatory instability (AMRI) of the knee is a complex and severe condition caused by injury to the anterior cruciate ligament and/or the medial collateral ligament. Clinical studies dealing with AMRI are rare, and objective measurements are nonexistent.

PURPOSE/HYPOTHESIS

The objectives of this study were, first, to quantify anteromedial rotatory knee laxity in healthy individuals using a noninvasive image analysis software and, second, to assess intra- and interrater reliability and equivalence in measuring anteromedial knee translation (AMT). It was hypothesized that AMT could be reliably quantified using a noninvasive image analysis software.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This prospective proof-of-concept study included healthy individuals aged 16 to 40 years with no history of knee injury or surgery. Three adhesive surface markers were placed on predefined landmarks on the medial side of the knee. Three independent investigators examined anteromedial rotatory knee laxity with an anterior drawer test in different tibial rotations (neutral tibial rotation, 15° of external tibial rotation, and 15° of internal tibial rotation). The entire examination of each knee was recorded, and AMT including the side-to-side difference (SSD) was assessed using a freely available and validated image analysis software (PIVOT iPad application). Group comparisons were performed using a 1-way analysis of variance with Bonferroni-adjusted post hoc analysis. Intraclass correlation coefficients (ICCs) were calculated to assess inter- and intrarater reliability of AMT measurements. Equivalence of measurements was evaluated using the 2 one-sided t-test procedure.

RESULTS

Anteromedial rotatory knee laxity was assessed in 30 knees of 15 participants (53% male) with a mean age of 26.2 ± 3.5 years. In all 3 raters, the highest AMT was observed in neutral tibial rotation (range of means, 2.2-3.0 mm), followed by external tibial rotation (range of means, 2.0-2.4 mm) and internal tibial rotation (range of means, 1.8-2.2 mm; P < .05). Intrarater reliability of AMT (ICC, 0.88-0.96) and SSD (ICC, 0.61-0.96) measurements was good to excellent and moderate to excellent, respectively. However, interrater reliability was poor to moderate for AMT (ICC, 0.44-0.73) and SSD (ICC, 0.12-0.69) measurements. Statistically significant equivalence of AMT and SSD measurements was observed between and within raters for almost all testing conditions.

CONCLUSION

Anteromedial rotatory knee laxity could be quantified using a noninvasive image analysis software, with the highest AMT observed during neutral tibial rotation in uninjured individuals. Reliability and equivalence of measurements were good to excellent within raters and moderate between raters.

Lateral Extra-articular Tenodesis Does Not Decrease Graft Failure in Revision Anterior Cruciate Ligament Reconstruction When Combined With Quadriceps or Patellar Tendon Grafts

PURPOSE

To compare return-to-sport (RTS) rates, graft failure rates, and clinical outcomes in patients who underwent revision anterior cruciate ligament reconstruction (R-ACLR) with additional lateral extra-articular tenodesis (LET) versus isolated R-ACLR.

METHODS

A retrospective review of the medical records of patients who underwent R-ACLR with or without a modified Lemaire LET procedure was performed. Seventy-four patients with at least 2 years of follow-up who had high-grade positive pivot-shift test findings were included. Concomitant procedures such as meniscectomy and meniscal repair were collected, along with any complications and/or graft failure. The Knee Injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee Subjective Knee Form score were collected. The ability to RTS was defined as fully, partially, or not returned.

RESULTS

Of the patients, 39 underwent isolated R-ACLR (mean age ± standard deviation, 29.2 ± 12.2 years) whereas 35 underwent an additional LET procedure (mean age, 24.6 ± 7.4 years). The mean length of follow-up in the R-ACLR group was 56.6 ± 26.5 months compared with 44.3 ± 17.6 months in the R-ACLR-LET group (P = .02) (range, 24-120 months). Patient-reported outcome measures were higher in the R-ACLR-LET group, with the KOOS Activities of Daily Living (93.5 ± 2.0 vs 97.2 ± 1.6, P = .03) and KOOS Sport (63.0 ± 3.6 vs 74.3 ± 3.8, P = .05) subdomain scores reaching the level of statistical significance. No differences were found in the other KOOS subdomain scores or the International Knee Documentation Committee scores. Failure rates were not significantly different between the groups (12.8% for R-ACLR vs 11.4% for R-ACLR-LET, P = .99). There were 13 patients (72.2%) in the R-ACLR group and 14 patients (60.8%) in the R-ACLR-LET group who did not RTS.

CONCLUSIONS

R-ACLR with additional LET showed similar failure and RTS rates to isolated R-ACLR after failed ACLR. The R-ACLR-LET group showed better functional results with significantly higher KOOS subdomain scores for activities of daily living, as well as sports and recreation. However, this study was unable to recommend the modified Lemaire LET procedure to be routinely used in R-ACLR patients.

LEVEL OF EVIDENCE

Level III, retrospective comparative therapeutic trial.

A Novel Predictor of the Length and Size of ACL Grafts in Chinese Han Adults for ACL Reconstruction: An MRI Study

OBJECTIVE

Currently, there is no simple and valid method to predict the length and size of the native anterior cruciate ligament (ACL) in each adult patient who will undergo ACL reconstruction. This study aimed to develop an imaging prediction method that can predict the length and size of ACL grafts using the intact posterior cruciate ligament (PCL), in order to enhance the graft preparation individualized sizing.

METHODS

Three hundred and nineteen patients aged 18 years or older who underwent magnetic resonance imaging (MRI) of the knee at an orthopaedic clinic between September 9, 2021, and February 5, 2023, were included. The length, sagittal diameter, and coronal diameter of the ACL and PCL were measured in all patients, and F-test were performed to explore linear relationship between ligament measurements.

RESULTS

Equations were established to predict a variable of the native ACL for the corresponding variable of the intact PCL (i.e., sagittal diameter of the ACL = 4.32 + 1.08 × sagittal diameter of the PCL, and coronal diameter of the ACL = 2.45 + 0.59 × coronal diameter of the PCL, length of the male ACL = 10.92 + 0.64 × length of the male PCL, length of the female ACL = 11.76 + 0.58 × length of the female PCL) (R2  = 0.532; R2  = 0.417; R2  = 0.488; R2  = 0.509; respectively).

CONCLUSIONS

The length and size of the intact PCL in cases without PCL buckling are predictors of the length and size of the native ACL in adults, respectively. The use of this information to optimize graft diameter may lower the rates of ACL graft failure in the future.

Role of Lateral Extra-articular Tenodesis in Restraining Internal Tibial Rotation: In Vitro Biomechanical Assessment of Lateral Tissue Engagement

BACKGROUND

The way in which force increases in the anterolateral tissues and the lateral extra-articular tenodesis (LET) tissue to resist internal rotation (IR) of the tibia after anterior cruciate ligament (ACL) reconstruction in isolation and after LET augmentation, respectively, is not well understood.

PURPOSE

(1) To compare in a cadaveric model how force increases (ie, engages) in the anterolateral tissues with IR of the tibia after isolated ACL reconstruction and in the LET tissue after augmentation of the ACL reconstruction with LET and (2) to determine whether IR of the tibia is related to engagement of the LET tissue.

STUDY DESIGN

Controlled laboratory study.

METHODS

IR moments were applied to 9 human cadaveric knees at 0°, 30°, 60°, and 90° of flexion using a robotic manipulator. Each knee was tested in 2 states: (1) after isolated ACL reconstruction with intact anterolateral tissues and (2) after LET was performed using a modified Lemaire technique with the LET tissue fixed at 60° of flexion under 44 N of tension. Resultant forces carried by the anterolateral tissues and the LET tissue were determined via superposition. The way force increased in these tissues was characterized via parameters of tissue engagement, namely in situ slack, in situ stiffness, and tissue force at peak applied IR moment, and then compared (α < .05). IR was related to parameters of engagement of the LET tissue via simple linear regression (α < .05).

RESULTS

The LET tissue exhibited less in situ slack than the anterolateral tissues at 30°, 60°, and 90° of flexion (P≤ .04) and greater in situ stiffness at 30° and 90° of flexion (P≤ .043). The LET tissue carried greater force at the peak applied IR moment at 0° and 30° of flexion (P≤ .01). IR was related to the in situ slack of the LET tissue (R2≥ 0.88; P≤ .0003).

CONCLUSION

LET increased restraint to IR of the tibia compared with the anterolateral tissue, particularly at 30°, 60°, and 90° of flexion. IR of the tibia was positively associated with in situ slack of the LET tissue.

CLINICAL RELEVANCE

Fixing the LET at 60° of flexion still provided IR restraint in the more functionally relevant flexion angle of 30°. Surgeons should pay close attention to the angle of internal and/or external tibial rotation when fixing the LET tissue intraoperatively because this surgical parameter is related to in situ slack of the LET tissue and, therefore, the amount of IR of the tibia.

A Cadaveric Study of the Optimal Isometric Region on the Anterolateral Surface of the Knee in Anterolateral Ligament Reconstruction

OBJECTIVE

Isolated intra-articular anterior cruciate ligament (ACL) reconstruction is not capable of restoring instability in many cases leading some to recommend concomitant anterolateral ligament (ALL) reconstruction. The satisfactory fixation site and graft length change are crucial in ligament reconstruction to restore the ALL function and avoid some unwanted graft behavior. The purpose of this investigation is to determine the optimal isometric region on the anterolateral aspect of the knee for ALL reconstruction using a three-dimensional optical instrument and a suture similar to an intraoperative isometric test.

METHODS

Six freshly frozen cadaveric human knees were used in this study. Data regarding the anterolateral surface were obtained using an optical measurement system to create a three-dimensional model. Nine points were selected on the femur (F1-F9) and tibia (Ta-Ti) respectively. The three-dimensional length change between each pair of tibial and femoral points was measured during passive knee flexion from 0° to 90° in 15° increments. Subsequently, five femoral points (A-E) were selected from the lateral femur, located in different areas relative to the lateral femoral epicondyle, and three tibial reference points (T1-T3) were selected in the isometric test. The changes in the length between each pair of reference points were measured using sutures. The 95% confidence interval for the rate of length change was estimated using the mean and standard deviation of the maximum rate of length change at different flexion angles, and the data were expressed as the mean (95% confidence interval) and compared with the maximum acceptable rate of change (10%).

RESULTS

The maximum acceptable change rate for ligament reconstruction is 10%, and the mean maximum rates and the 95% confidence interval (CI) of length change for the point combinations were calculated. Among all the combined points measured using the optical measurement system and the suture, the qualified point combination for reconstruction was F3 (8mm posterior and 8mm proximal to the lateral femoral epicondyle)-Tb (8mm proximal to the midpoint between the center of Gerdy's tubercle and the fibula head), A (posterior and proximal to the lateral femoral epicondyle)-T2 (10mm below the joint line)and A-T3 (15 mm below the joint line). The position of F3-Tb and A-T2 are close to each other.

CONCLUSION

The most isometric area of the femur for ALL reconstruction was posterior and proximal to the lateral femoral epicondyle. We recommend that the initial location of the femoral point be set at 8 mm posterior and 8 mm proximal to the lateral femoral epicondyle and the tibial point at approximately 10 mm below the joint line, midway between Gerdy's tubercle and fibular head, and subsequently adjusted to the most satisfactory position according to the isometric test.

Progress in research on and classification of surgical methods of arthroscopic reconstruction of the ACL and ALL using a shared tendon graft through the femoral tunnel

Anterior cruciate ligament (ACL) tear is a common clinical injury, and ACL reconstruction has reached a very mature stage. However, with the accumulation of cases, scholars have found that isolated ACL reconstruction may not completely solve the problem of knee rotational stability. With the increase in our understanding of knee joint structure, ACL combined with anterolateral ligament (ALL) reconstruction has become accepted by most scholars, and this operation has also achieved good clinical results. At present, there is no unified surgical method for ACL combined with ALL reconstruction. There are differences in bone tunnel location, reconstruction methods, and graft selection. Compared with the independent reconstruction of the ACL and ALL during the operation, shared tendon graft reconstruction of the ACL and ALL has the advantages of preserving tendon and avoiding tunnel convergence. So far, there is no relevant literature summarizing the reconstruction of the ACL and ALL with a shared tendon graft. This paper reviews the anatomic study of the ALL, the study of isometric points, surgical indications, and surgical methods and their classification for shared tendon graft reconstruction of the ACL and ALL.

Lateral Extra-articular Tenodesis: The Onlay Technique

Tibial anterolateral rotary instability associated with anterior cruciate ligament (ACL) tears is a well-documented and difficult problem with a long history of solutions. The lateral extra-articular tenodesis (LET) has undergone multiple refinements in technique, largely focusing on the femoral site insertion using either an interference screw versus a staple for adequate fixation. In this article, we present an improved technique using a suture anchor as an alternative to a staple or an interference screw with secure fixation to insert the LET graft onto the femur. This technique diminishes the chance of ACL tunnel-LET drilling convergence, minimizes the footprint required for adequate graft fixation, and allows the surgeon to dial in the correct tension necessary for adequate augmentation of an ACL reconstruction.

Modified Lemaire Tenodesis Forces in Cadaveric Specimens Are Not Affected by Random Small-Scale Variations in the Femoral Insertion Point During Active Knee Joint Flexion-Extension

Purpose

To directly measure lateral extra-articular tenodesis (LET) forces supporting anterior cruciate ligament reconstruction (ACLR) during dynamic flexion-extension cycles induced by simulated active muscle forces, to investigate the influence of random surgical variation in the femoral LET insertion point around the target insertion position, and to determine potential changes to the extension behavior of the knee joint in a cadaveric model.

Methods

After iatrogenic anterior cruciate ligament deficiency and simulated anterolateral rotatory instability, 7 fresh-frozen cadaveric knee joints were treated with isolated ACLR followed by combined ACLR-LET. The specimens were tested on a knee joint test bench during active dynamic flexion-extension with simulated muscle forces. LET forces and the degree of knee joint extension were measured. Random variation in the LET insertion point around the target insertion position was postoperatively quantified by computed tomography.

Results

In extension, the median LET force increased to 39 ± 2 N (95% confidence interval [CI], 36 to 40 N). In flexion over 70°, the LET was offloaded (2 ± 1 N; 95% CI, 0 to 2 N). In this study, small-scale surgical variation in the femoral LET insertion point around the target position had a negligible effect on the graft forces measured. We detected no difference in the degree of knee joint extension after combined ACLR-LET (median, 1.0° ± 3.0°; 95% CI, -6.2° to 5.2°) in comparison with isolated ACLR (median, 1.1° ± 3.3°; 95% CI, -6.7° to 6.1°; P = .62).

Conclusions

LET forces in combined ACLR-LET increased to a limited extent during active knee joint flexion-extension independent of small-scale variation around 1 specific target insertion point. Combined ACLR-LET did not change knee joint extension in comparison with isolated ACLR under the testing conditions used in this biomechanical study.

Clinical Relevance

Low LET forces can be expected during flexion-extension of the knee joint. Small-scale deviations in the femoral LET insertion point around the target insertion position in the modified Lemaire technique might have a minor effect on graft forces during active flexion-extension.

"Over-the-Top" Anterior Cruciate Ligament Reconstruction Associated With a Lateral Extra-Articular Tenodesis in Children

Anterior cruciate ligament (ACL) tears are one of the most frequent injuries in growing children, and they are often associated with other injuries such as meniscal and chondral injuries. In the past, treatment of ACL tears in growing patients relied on activity modification and bracing. However, surgical treatment has prevailed over conservative treatment in recent years. A surgical technique is presented for ACL reconstruction using an "over-the-top" technique associated with a lateral extra-articular tenodesis procedure in children. An extra-articular lateral tenodesis is done first. The gracilis and semitendinous tendons are then extracted using a tenotome without releasing their distal desinsertions. The tibial guide is then centered over the ACL tibial footprint under arthroscopic vision and an image intensifier, proximal to the physis. Then, a Kocher-type forceps is used to pass a suture "over the top" from the posterolateral window to the tibial tunnel. The double-bundle graft and iliotibial tract graft are fixed within the tunnel in full extension and neutral rotation with an interference screw.

Comparison of Anterior Cruciate Ligament Reconstruction With Versus Without Anterolateral Augmentation: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Background

It is clear that the anterolateral ligament has an important role in rotational knee stability. However, whether patients undergoing anterior cruciate ligament (ACL) reconstruction (ACLR) can benefit from anterolateral augmentation (ALA) is still controversial.

Purpose

To compare the effects of isolated ACLR versus ACLR combined with ALA (ACLR+ALA) on clinical outcomes and knee stability.

Study Design

Systematic review; Level of evidence, 1.

Methods

The methodology followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A literature search of the PubMed, Embase, and Cochrane Library Central Register of Controlled Trials databases was undertaken to identify all randomized controlled trials (RCTs) comparing isolated ACLR with ACLR+ALA for the treatment of ACL injuries in the last 15 years. The Cochrane Collaboration risk-of-bias tool and the revised Jadad scale were utilized by 2 independent reviewers to determine the quality of RCTs. Relevant data were extracted and compared between procedures, and heterogeneity across the RCTs was assessed using the I ² statistic.

Results

The initial search yielded 849 articles. A total of 14 studies (1850 patients; 941 ACLR and 909 ACLR+ALA) satisfied the eligibility criteria for the meta-analysis. There were no significant differences between the procedures in terms of patient-reported outcomes (International Knee Documentation Committee score, Tegner score, Knee injury and Osteoarthritis Outcome Score) or return-to-sport rates. However, patients who underwent ACLR+ALA had better knee stability based on the pivot-shift test (risk ratio [RR], 1.06 [95% CI, 1.02 to 1.10]; P = .0008), Lachman test (RR, 1.03 [95% CI, 1.00 to 1.07]; P = .04), and side-to-side difference in anterior laxity (standardized mean difference, -0.55 [95% CI, -0.98 to -0.12]; P = .01) as well as a lower incidence of graft failure (RR, 0.30 [95% CI, 0.19 to 0.45]; P < .01) compared with patients who underwent isolated ACLR.

Conclusion

ALA can be considered as a reinforcement of ACLR to improve anteroposterior and anterolateral rotational stability of the knee and reduce the risk of failure. The patient-reported outcomes of isolated ACLR were similar to those of ACLR+ALA, and both procedures provided improved knee function.

Anatomical and Biomechanical Characteristics of the Anterolateral Ligament: A Descriptive Korean Cadaveric Study Using a Triaxial Accelerometer

Background and Objectives: The anterolateral ligament (ALL) could be the potential anatomical structure responsible for rotational instability after anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to investigate the anatomical and biomechanical characteristics of the ALL in Korean cadaveric knee joints. Materials and Methods: Twenty fresh-frozen cadaveric knees were dissected and tested. Femoral and tibial footprints of the ALL were recorded. Pivot shift and Lachman tests were measured with KiRA. Results: The prevalence of ALL was 100%. The average distance of the tibial footprint to the tip of the fibular head was 19.85 ± 3.41 mm; from the tibial footprint to Gerdy's tubercle (GT) was 18.3 ± 4.19 mm; from the femoral footprint to the lateral femoral epicondyle was 10.25 ± 2.97 mm. ALL's footprint distance was the longest at 30° of flexion (47.83 ± 8.05 mm, p < 0.01) in a knee with intact ALL-ACL and neutral rotation. During internal rotation, the footprint distance was the longest at 30° of flexion (50.05 ± 8.88 mm, p < 0.01). Internal rotation produced a significant increase at all three angles after ACL-ALL were transected (p = 0.022), where the footprint distance was the longest at 30° of flexion (52.05 ± 7.60 mm). No significant difference was observed in KiRA measurements between intact ALL-ACL and ALL-transected knees for pivot shift and Lachman tests. However, ACL-ALL-transected knees showed significant differences compared to the intact ALL-ACL and ALL-transected knees (p < 0.01). Conclusions: The ALL was identified as a distinct ligament structure with a 100% prevalence in this cadaveric study. The ALL plays a protective role in internal rotational stability. An isolated ALL transection did not significantly affect the ALL footprint distances or functional stability tests. Therefore, the ALL is thought to act as a secondary supportive stabilizer for rotational stability of the knee joint in conjunction with the ACL.

A Landmark-Based Technique for Determining an Isometric Femoral Attachment Site for Lateral Extraarticular Tenodesis is Inaccurate

Purpose

To evaluate the reliability and accuracy of a method of placing the femoral fixation location for lateral extra-articular tenodesis (LET) within a safe isometric area using anatomic landmarks.

Methods

Using a pilot cadaveric specimen, the center of the radiographic safe isometric area for femoral fixation of LET, defined as a 1 cm (proximal-distal) area located proximal to the metaphyseal flare and posterior to the posterior cortical extension line (PCEL), was located using fluoroscopy and found to be 20 mm directly proximal to the center of the fibular collateral ligament (FCL) origin. Using 10 additional specimens, the center of the FCL origin and a location 20 mm directly proximal was identified. K-wires were placed at each location. A lateral radiograph was obtained, and distances of the proximal K-wire relative to the PCEL and metaphyseal flare were measured. The location of the proximal K-wire relative to the radiographic safe isometric area was assessed by 2 independent observers. Intrarater and inter-rater reliability was calculated for all measurements using intraclass coefficients (ICCs).

Results

There was excellent intrarater and inter-rater reliability for all radiographic measurements (.908 to .975 and .968 to .988, respectively). In 5/10 specimens, the proximal K-wire was outside of the radiographic safe isometric area, with 4/5 anterior to the PCEL. Overall, the mean distance from the PCEL was 1 mm ± 4 mm (anterior), and the mean distance from the metaphyseal flare was 7.4 mm ± 2.9 mm (proximal).

Conclusion

A landmark-based technique referencing the FCL origin was inaccurate in the placement of femoral fixation within a radiographic safe isometric area for LET. Therefore intraoperative imaging should be considered to ensure accurate placement.

Clinical Relevance

These findings may help to decrease the likelihood of misplacement of femoral fixation during LET by showing that landmark-based methods without intraoperative image guidance may be unreliable.

Modified Lemaire Lateral Extra-articular Tenodesis With the Iliotibial Band Strip Fixed on the Femoral Cortical Surface Reduces Laxity and Causes Less Overconstraint in the Anterolateral Lesioned Knee: A Biomechanical Study

PURPOSE

To compare the biomechanical effects of femoral cortical surface fixation and intra-tunnel fixation in modified Lemaire tenodesis on the restoration of native kinematics in anterolateral structure-deficient knees.

METHODS

Eight fresh-frozen cadaveric knees were mounted in a knee-customized jig to evaluate anterior translation in anterior load and internal rotation degree in internal rotation torque at 0°, 30°, 60°, and 90°, as well as anterolateral translation (ALT) in a simulated pivot-shift test at 0°, 15°, 30°, and 45°. Kinematic tests were performed in the following states: intact; anterolateral knee lesion (AL-Les); modified Lemaire lateral extra-articular tenodesis (LET) with the femoral iliotibial band (ITB) strip fixed on the cortical surface (cortical fixation), deep to the lateral collateral ligament (LCL) (deep LET-C); and LET with the femoral ITB strip fixed into a tunnel (intra-tunnel fixation), deep to the LCL (deep LET-IT) or superficial to the LCL (superficial LET-IT). The knee kinematic changes in the AL-Les state and the 3 LET states were compared with each other, with the intact state as the baseline.

RESULTS

In the AL-Les state, the increased anterior translation instabilities were significantly mitigated by the 3 LETs at 30°, 60°, and 90° (all P < .001), with overconstraint observed in both the deep LET-IT and superficial LET-IT states at 60° (P = .047 and P < .001, respectively) and 90° (both P < .001). Similarly, the 3 LETs significantly reduced the internal rotation instabilities in the AL-Les state at all flexion angles. The superficial LET-IT state overconstrained the knee at 60° (P = .009) and 90° (P < .001) during internal rotation torque, and the deep LET-IT state did so at 60° (P = .012). Furthermore, the ALT instabilities found in the AL-Les state were significantly reduced by the 3 LETs during the simulated pivot-shift test. At 30° and 45°, these LET states resulted in overconstraint when compared with the intact state, but the superficial LET-IT state (P < .001) or deep LET-IT state (P = .016) presented a larger overconstraint than that in the deep LET-C at 45°, respectively.

CONCLUSIONS

The 3 Lemaire LET procedures evaluated reduced the anterior, internal rotational, and ALT laxities in AL-Les knees and restored these parameters to the native baseline of the intact state at most flexion angles. However, in deep flexion, some overconstraint occurred in all LETs when compared with the intact state, of which the deep LET-C state resulted in less overconstraint in anterior translation and internal rotation than the deep LET-IT and superficial LET-IT states.

CLINICAL RELEVANCE

This biomechanical study supports using the femoral cortical fixation technique to fix the ITB strip in the modified Lemaire LET, which similarly improves knee kinematic stability and causes less overconstraint compared with conventional intra-tunnel fixation. These findings need more verification in clinical scenarios.

Editorial Commentary: Lateral Extra-articular Procedures Concomitant to Anterior Cruciate Ligament Reconstruction Must Balance Clinical Efficacy and the Risk of Kinematic Restraint

Lateral extra-articular procedures (LEAPs) performed concomitant to anterior cruciate ligament reconstruction improve clinical outcomes and can restore normal knee kinematics. However, some LEAPs may result in overconstraint depending on technique. When using an iliotibial band based technique, passing the graft deep to the lateral collateral ligament and fixing it on the lateral cortex (rather than in a tunnel with an interference screw) minimizes the risk of tunnel collision and may also reduce the risk of overconstraint. Although several laboratory studies report overconstraint with iliotibial band based procedures, clinical reports of overconstraint are rare. This may be due to lack of a clear definition of clinical overconstraint and resultant underdiagnosis. However, long term randomised controlled study has demonstrated significantly higher rates of osteoarthritis when a modified Lemaire is added to an anterior cruciate ligament reconstruction. There is clearly a need for further study and in the meantime clinical efficacy must be balanced with the risk of kinematic restriction.

Effect of Lateral Extra-articular Tenodesis on the Rate of Revision Anterior Cruciate Ligament Reconstruction in Elite Athletes

BACKGROUND

There is growing evidence that anterolateral procedures can reduce the risk of rerupture in high-risk recreational athletes undergoing primary anterior cruciate ligament (ACL) reconstruction (ACLR). However, this effectiveness has never been evaluated in elite athletes.

PURPOSE

The purpose of this study was to evaluate the effectiveness of lateral extra-articular tenodesis (LET) in reducing revision rates in primary ACLR in elite athletes. Additionally, this study evaluated whether LET had a greater effect when combined with ACLR utilizing a hamstring or patellar tendon graft.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A consecutive cohort of elite athletes with an isolated ACL tear undergoing autograft patellar or hamstring tendon reconstruction with or without Lemaire LET were analyzed between 2005 and 2018. A minimum 2-year follow-up was required. The association between the use of LET and ACL graft failure as defined by revision ACLR was evaluated with univariate and multivariate logistic regression models.

RESULTS

A total of 455 elite athletes (83% men and overall age 22.5 ± 4.7 years) underwent primary ACLR with (n = 117) or without (n = 338) a LET procedure. Overall, 36 athletes (7.9%) experienced ACL graft failure, including 32 (9.5%) reconstructions without a LET and 4 (3.4%) with a LET. Utilization of LET during primary ACLR reduced the risk of graft failure by 2.8 times, with 16.5 athletes needing LET to prevent a single ACL graft failure. Multivariate models showed that LET significantly reduced the risk of graft rupture (relative risk = 0.325; P = .029) as compared with ACLR alone after controlling for sex and age at ACLR. Including graft type in the model did not significantly change the risk profile, and although a patellar tendon graft had a slightly lower risk of failure, this was not statistically significant (P = .466).

CONCLUSION

The addition of LET reduced the risk of undergoing revision by 2.8 times in elite athletes undergoing primary ACLR. This risk reduction did not differ significantly between the patellar tendon and hamstring tendon autografts. With these results, status as an elite athlete should be included in the indications for a LET, as they are at increased risk for ACL graft failure.

Transepicondylar distance measured on MRI can predict the length of the graft required for different anterior cruciate ligament reconstruction (ACLR) techniques useful for revision surgery

Background

The aim of this study is to find a correlation between linear measurements and the graft length required for different anterior cruciate ligament (ACL) revision techniques, to extract formulas to predict required graft length during the preoperative planning.

Methods

At time 0 and 30 days later, two observers measured eight linear distances on standard 2D knee magnetic resonance imaging (MRI), and nine curved distances on 3D MRI sequences, corresponding to different techniques for ACL revision, anatomic anterolateral ligament (ALL) reconstruction, and lateral extrarticular tenodesis (LET). Intra- and interobserver reliability was tested for 2D and 3D measurements. The correlation between 2D and 3D measurements was tested. The 2D measurements with highest repeatability and reproducibility, and with strongest correlation with 3D measurements were used to extract formulas to calculate the graft length from 2D values.

Results

Fifty MRIs acquired with both 2D and 3D sequences were used. The intra- and interobserver reliability of linear 2D measurement was high, with the transepicondylar distance (TD) showing the highest reproducibility and repeatability. The intra- and interobserver reliability of 3D measurements was lower than 2D, but acceptable for all measurements except for ALL reconstruction. The TD showed the strongest correlation with 3D measurements. The formulas extracted to calculate the graft length from the TD proved to be accurate.

Conclusion

Accurate formulas were created to calculate the graft length needed for different ACL revision techniques and ALL reconstruction/LET techniques from TD. These formulas can be used during preoperative planning of ACL revision cases.

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 complex of the knee: State of the art

Rotatory instability of the knee represents the main reason for failure and poor clinical outcomes regarding anterior cruciate ligament (ACL) reconstruction techniques. It is now clear that the anterolateral complex (ALC) of the knee possesses a fundamental role, in association with the ACL, in controlling internal rotation. Over the past decade, ever since the anterolateral ligament has been identified and described as a distinct structure, there has been a renewed interest in the scientific community about the whole ALC: Lateral extra-articular tenodesis have made a comeback in association with ACL reconstructions to improve functional outcomes, reducing the risks of graft failure and associated injuries. Modern ACL reconstruction surgery must therefore investigate residual instability and proceed, when necessary, to extra-articular techniques, whether functional tenodesis or anatomical reconstruction.This review aims to investigate the latest anatomical and histological descriptions, and the role in rotational control and knee biomechanics of the ALC and its components. The diagnostic tools for its identification, different reconstruction techniques, and possible surgical indications are described.. In addition, clinical and functional results available in the literature are reported.

Imaging Findings of Complications After Lateral Extra-Articular Tenodesis of the Knee: A Current Concepts Review

Background:

Despite successful anterior cruciate ligament (ACL) reconstruction, many patients continue to experience persistent anterolateral rotatory instability. Lateral extra-articular tenodesis (LET) is used to address this instability by harvesting a portion of the iliotibial band, passing it underneath the fibular collateral ligament, and attaching it just proximal and posterior to the lateral femoral epicondyle. Based on the most recent clinical evidence, the addition of LET to ACL reconstruction improves clinical outcomes, which has led to an increase in the use of this technique.

Purpose:

To provide an overview of the postoperative complications of the LET procedure and their associated imaging findings, with a focus on magnetic resonance imaging (MRI).

Study Design:

Narrative review.

Methods:

In this scoping review, the authors reviewed available radiographic, computed tomography, and MRI scans of patients who experienced postoperative complications after ACL reconstruction with LET, in which the complication was determined to be from the LET procedure. Images were reviewed and subsequently described by an on-staff musculoskeletal radiologist.

Results:

The authors found 9 different complications associated with LET: graft failure, hematoma, infection, chronic pain, tunnel convergence, fixation device migration, muscular hernia, peroneal nerve palsy, and knee stiffness. They supplemented these findings with radiographic evidence from 6 patients.

Conclusion:

As extra-articular reconstruction techniques including LET become more popular among orthopaedic surgeons, it is important that radiologists and surgeons be adept at recognizing the normal imaging findings of LET and associated complications.

Factors affecting return to play and graft re-rupture after primary ACL reconstruction in professional footballers

PURPOSE

Modern ACL reconstruction (ACL-R) techniques have led to improved outcomes in professional footballers. The aim of this study was to identify and assess patient, surgical and post-operative factors that affected rates and time to return to play (RTP) as well as ACL re-rupture rates.

METHODS

A retrospective review of consecutive ACL-R undertaken in professional footballers between 2005 and 2018.

RESULTS

Two-hundred and thirty-two knees in 215 professional footballers (17 bilateral) were included. 205 (88.9%) were male and average age at surgery was 23.3 ± 4.4 years. Two-hundred and twenty-two (96.1%) returned to professional football, with 209 (90.1%) returning to the same or higher Tegner level. Subgroup analysis revealed three factors that independently affected RTP rate: (1) Players under 25 years had a higher rate of RTP (99.3% vs 90.2%. p = 0.001); (2) a subsequent operation prior to RTP decreased RTP rate from 98.2 to 89.7% (p = 0.009).; (3) undergoing meniscal surgery at ACL-R decreased RTP rate (p = 0.002). The mean time to RTP from surgery was 10.5 ± 3.6 months. Factors found to increase RTP time included age under 25 (11.0 vs 9.7 months, p = 0.005), recurrent effusions (11.4 vs 10.2 months, p = 0.035), and medial meniscal repair at ACL-R compared to meniscectomy (12.5 vs 9.6 months, p = 0.022). The surgical technique varied over the study period in relation to graft type, femoral tunnel position and addition of lateral extra-articular tenodesis (LET). Overall, the re-rupture rate was 8.2% at 2 years. Patella tendon autograft in an anteromedial bundle femoral tunnel position with addition of LET has the lowest re-rupture rate (2.0%).

CONCLUSION

Primary ACL-R in professional footballers yields high rates of RTP (96.1%), with 90.1% at the same level or higher, at a mean 10.5 months. Patients under 25 years not only had a significantly higher RTP rate, but also had a lengthier period of rehabilitation.

LEVEL OF EVIDENCE

Level IV.

Anatomy, Biomechanics, and Reconstruction of the Anterolateral Ligament of the Knee Joint

Despite remarkable advances in the clinical outcomes after anterior cruciate ligament reconstructions (ACLRs), residual rotational instability of the knee joint remains a major concern. Since the anterolateral ligament (ALL) on the knee joint has been “rediscovered”, the role of anterolateral structures, including ALL and deep iliotibial band, as secondary stabilizers of anterolateral rotatory instability has gained interest. This interest has led to the resurgence of anterolateral procedures combined with ACLRs to restore rotational stability in patients with anterior cruciate ligament (ACL) deficiencies. However, the difference in concepts between anterolateral ligament reconstructions (ALLRs) as anatomical reconstruction and lateral extra-articular tenodesis (LETs) as non-anatomical reinforcement has been conflicting in present literature. This study aimed to review the anatomy and biomechanics of anterolateral structures, surgical techniques, and the clinical outcomes of anterolateral procedures, including LET and ALLR, in patients with ACL deficiencies.

Modified Lemaire tenodesis reduces anterior cruciate ligament graft forces during internal tibial torque loading

PURPOSE

The aim of the study was to directly measure graft forces of an anterior cruciate ligament reconstruction (ACLR) and a lateral extra-articular tenodesis (LET) using the modified Lemaire technique in combined anterior cruciate ligament (ACL) deficient and anterolateral rotatory instable knees and to analyse the changes in knee joint motion resulting from combined ACLR + LET.

METHODS

On a knee joint test bench, six fresh-frozen cadaveric specimens were tested at 0°, 30°, 60°, and 90° of knee flexion in the following states: 1) intact; 2) with resected ACL; 3) with resected ACL combined with anterolateral rotatory instability; 4) with an isolated ACLR; and 5) with combined ACLR + LET. The specimens were examined under various external loads: 1) unloaded; 2) with an anterior tibial translation force (ATF) of 98 N; 3) with an internal tibial torque (IT) of 5 Nm; and 4) with a combined internal tibial torque of 5 Nm and an anterior tibial translation force of 98 N (IT + ATF). The graft forces of the ACLR and LET were recorded by load cells incorporated into custom devices, which were screwed into the femoral tunnels. Motion of the knee joint was analysed using a 3D camera system.

RESULTS

During IT and IT + ATF, the addition of a LET reduced the ACLR graft forces up to 61% between 0° and 60° of flexion (P = 0.028). During IT + ATF, the LET graft forces reached 112 N. ACLR alone did not restore native internal tibial rotation after combined ACL deficiency and anterolateral rotatory instability. Combined ACLR + LET was able to restore native internal tibial rotation values for 0°, 60° and 90° of knee flexion with decreased internal tibial rotation at 30° of flexion.

CONCLUSION

The study demonstrates that the addition of a LET decreases the forces seen by the ACLR graft and reduces residual rotational laxity after isolated ACLR during internal tibial torque loading. Due to load sharing, a LET could support the ACLR graft and perhaps be the reason for reduced repeat rupture rates seen in clinical studies. Care must be taken not to limit the internal tibial rotation when performing a LET.

Combined lateral extra-articular tenodesis and anterior cruciate ligament reconstruction: risk of osteoarthritis

PURPOSE

Lateral extra-articular tenodesis (LET) procedure, combined with an intra-articular reconstruction of the anterior cruciate ligament (ACL), is used to reduce rotational laxity and the risk of graft failure. However, concern of overtightening of the lateral compartment and subsequent osteoarthritis remains. The aim of this study is to evaluate the degenerative changes in the lateral compartment and to compare the clinical and radiographical results between two LET techniques.

METHODS

Eighty-three patients (86 knees) were retrospectively reviewed at a mean of 67.7 months (range 49-85 months). Forty-two knees had an ACL reconstruction combined with a LET procedure according to the modified Lemaire technique and 44 knees according to the modified Coker-Arnold technique. IKDC, Lysholm, Tegner and VAS scores were used. Osteoarthritis was radiographically evaluated by the Kellgren-Lawrence classification.

RESULTS

There were 12 patients (28.6%) in the modified Lemaire subgroup and 13 patients (29.5%) in the modified Coker-Arnold subgroup that had doubtful or mild radiologic signs of osteoarthritis. No patients had moderate or severe signs at final follow-up. There was no significant difference in radiological signs of osteoarthritis. In the modified Lemaire subgroup, we report a mean IKDC of 86.31 (± 13.794), a mean Lysholm of 87.83 (± 12.802) and a mean Tegner of 5.38 (± 2.556). In the modified Coker-Arnold subgroup, a mean IKDC of 87.27 (± 11.653), a mean Lysholm of 91.89 (± 8.035) and a mean Tegner of 5.16 (± 2.420) were reported. There were no statistical significant differences between both techniques. In eight patients, a complication was identified, 3 of which had a failure of the ACL reconstruction.

CONCLUSIONS

The chosen LET-technique seems to have minimal effect on both the clinical and the radiographic results. The LET is a safe procedure, and it does not increase the risk of osteoarthritis in the lateral compartment.

Tunnel Convergence Rate in Combined Anteromedial Portal Anterior Cruciate Ligament and Anterolateral Structure Reconstructions Is Influenced by Anterior Cruciate Ligament Knee Flexion Angle, Tunnel Position, and Direction

PURPOSE

The goal of the present study was to evaluate a potential tunnel convergence in combined anterior cruciate ligament (ACL) reconstruction using the anteromedial portal technique and lateral extra-articular tenodesis (LET).

METHODS

Ten fresh frozen femora were dissected and a K-wires were inserted into the middle of the ACL stump, according to an ACL reconstruction at 110° and 140° knee flexion. ACL reconstruction at 120° and 130° was simulated. Seven K-wires with different femoral insertion sites and angulations were drilled into the lateral femoral condyle relative to the lateral epicondyle (E3: 8 mm proximal and 4 mm posterior; E1: 5 mm proximal and 5 mm anterior and E2: over-the-top position). Tunnel conflict rate was evaluated using a measuring arm and a metrology software.

RESULTS

Drilling the femoral ACL tunnel in low knee flexion (110°-120°) significantly (P < .001) reduced the tunnel conflict rate compared to the ACL drilled in high knee flexion (130°-140°). Changing the insertion point from proximal and posterior (E3) to proximal and anterior (E1) showed a reduced tunnel conflict rate from 40 ± 21.2% to 15 ± 26% and no tunnel conflict for an ACL drilled at 110°-130° knee flexion.

CONCLUSION

A possible tunnel conflict in simultaneous ACL reconstruction using the AMP technique and LET was dependent on ACL knee flexion angle, LET insertion site, and angulation. This posed the dilemma that no generally applicable LET configuration could be recommended to avoid a tunnel conflict. However, it appears that an insertion point located proximal and anterior to the lateral epicondyle results in less tunnel conflicts than an insertion point located proximal and posterior.

CLINICAL RELEVANCE

An insertion point located proximal and anterior to the lateral epicondyle with a 30° proximal and 30° anterior angulation could reliably avoid a tunnel conflict when the ACL was drilled between 110 and 130° using a low anteromedial portal.

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

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

Anterolateral Structure Reconstruction Similarly Improves the Stability and Causes Less Overconstraint in Anterior Cruciate Ligament-Reconstructed Knees Compared With Modified Lemaire Lateral Extra-articular Tenodesis: A Biomechanical Study

PURPOSE

To compare the kinematics of anterolateral structure (ALS) reconstruction (ALSR) and lateral extra-articular tenodesis (LET) in ACL-ALS-deficient knees with anterior cruciate ligament (ACL) reconstruction.

METHODS

Ten fresh-frozen cadaveric knees with the following conditions were tested: (1) intact, (2) ACL-ALS deficiency, (3) ACL reconstruction (ACLR), (4) ACLR combined with ALSR (ACL-ALSR) or LET (ACLR+LET). Anterior translation and tibial internal rotation were measured with 90-N anterior load and 5 N·m internal torque at 0°, 30°, 60°, and 90°. The anterolateral translation and internal rotation were also measured during a simulated pivot-shift test at 0°, 15°, 30°, and 45°. The knee kinematic changes in all reconstructions were compared with each other, with intact knees as the baseline.

RESULTS

Isolated ACLR failed to restore native knee kinematics in ACL-ALS-deficient knees. Both ACL-ALSR and ACLR+LET procedures decreased the anterior instability of the ACLR. However, ACLR+LET caused overconstraints in internal rotation at 30° (-3.73° ± 2.60°, P = .023), 60° (-4.96° ± 2.22°, P = .001) and 90° (-6.14° ± 1.60°, P < .001). ACL-ALSR also overconstrained the knee at 60° (-3.65° ± 1.90°, P < .001) and 90° (-3.18° ± 2.53°, P < .001). For a simulated pivot-shift test, both combined procedures significantly reduced the ACLR instability, with anterolateral translation and internal rotation being overconstrained in ACLR+LET at 30° (-3.32 mm ± 3.89 mm, P = .005; -2.58° ± 1.61°, P < .001) and 45° (-3.02 mm ± 3.95 mm, P = .012; -3.44° ± 2.86°, P < .001). However, the ACL-ALSR overconstrained only the anterolateral translation at 30° (-1.51 mm ± 2.39 mm, P = .046) and internal rotation at 45° (-2.09° ± 1.70°, P < .001). There were no significant differences between the two combined procedures at most testing degrees in each testing state, except for the internal rotation at 30° (P = .007) and 90° (P = .032) in internal rotation torque.

CONCLUSION

ACL reconstruction alone did not restore intact knee kinematics in knees with concurrent ACL tears and severe ALS injury (ACL-ALS-deficient status). Both ACL-ALSR and ACLR+LET procedures restored knee stability at some flexion degrees, with less overconstraints in internal rotation resulting from ACL-ALSR.

CLINICAL RELEVANCE

For patients with combined ACL tears and severe ALS deficiency, isolated ACLR probably results in residual rotational and pivot-shift instability. Both ACL-ALSR and ACLR+LET show promise for the improvement of knee stability, whereas ACL-ALSR has less propensity for knee overconstraint.

Femoral Positioning of the Anterolateral Ligament Graft With and Without Ultrasound Location of the Lateral Epicondyle

BACKGROUND

In anterior cruciate ligament (ACL) reconstruction with anterolateral ligament (ALL) reconstruction, precise positioning of the ALL graft on the femur and tibia is key to achieve rotational control. The lateral femoral epicondyle is often used as a reference point for positioning of the ALL graft and can be located by palpation or with ultrasound guidance.

PURPOSE

To compare the ALL graft positioning on the femoral side between an ultrasound-guided technique and a palpation technique for the location of the lateral epicondyle.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 120 patients receiving a primary combined ACL and ALL reconstruction between June and December 2019 were included. The location of the lateral epicondyle was determined by palpation in the palpation group (n = 60) and with preoperative ultrasound guidance in the ultrasound group (n = 60). Groups were comparable in age, sex, body mass index (BMI), and operated side. The planned positioning of the femoral ALL graft was proximal and posterior to the lateral epicondyle. The effective positioning of the femoral ALL graft was evaluated on postoperative lateral radiographs. The primary outcome was location of the graft in a 10-mm quadrant posterior and proximal to the lateral epicondyle. Results were analyzed in 2 subgroups according to BMI.

RESULTS

All 60 anterolateral grafts (100%) in the ultrasound group were positioned in a 10-mm quadrant posterior and proximal to the lateral epicondyle, as opposed to 52 (87%) in the palpation group (P = .006). Errors in graft positioning with palpation occurred in overweight patients (BMI >25) as well as nonoverweight patients (P = .3).

CONCLUSION

Femoral positioning of the ALL graft posterior and proximal to the lateral epicondyle is more reproducible with ultrasound guidance when compared with palpation alone, regardless of BMI.

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.

Partial and Combined Partial Knee Arthroplasty: Greater Anterior-Posterior Stability Than Posterior Cruciate-Retaining Total Knee Arthroplasty

BACKGROUND

Little is known regarding anterior-posterior stability after anterior cruciate ligament-preserving partial (PKA) and combined partial knee arthroplasty (CPKA) compared to standard posterior cruciate-retaining total knee arthroplasty (TKA).

METHODS

The anterior-posterior tibial translation of twenty-four cadaveric knees was measured, with optical tracking, while under 90N drawer with the knee flexed 0-90°. Knees were tested before and after PKA, CPKA (medial and lateral bicompartmental and bi-unicondylar), and then posterior cruciate-retaining TKA. The anterior-posterior tibial translations of the arthroplasty states, at each flexion angle, were compared to the native knee and each other with repeated measures analyses of variance and post-hoc t-tests.

RESULTS

Unicompartmental and bicompartmental arthroplasty states had similar laxities to the native knee and to each other, with ≤1-mm differences throughout the flexion range (P ≥ .199). Bi-unicondylar arthroplasty resulted in 6- to 8-mm increase of anterior tibial translation at high flexion angles compared to the native knee (P ≤ .023 at 80-90°). Meanwhile, TKA exhibited increased laxity across all flexion angles, with increased anterior tibial translation of up to 18 ± 6 mm (P < .001) and increased posterior translation of up to 4 ± 2 mm (P < .001).

CONCLUSIONS

In a cadaveric study, anterior-posterior tibial translation did not differ from native laxity after PKA and CPKA. Posterior cruciate ligament-preserving TKA demonstrated increased laxity, particularly in anterior tibial translation.

Medial collateral ligament reconstruction graft isometry is effected by femoral position more than tibial position

PURPOSE

The purpose of this study was to examine the length change patterns of the native medial structures of the knee and determine the effect on graft length change patterns for different tibial and femoral attachment points for previously described medial reconstructions.

METHODS

Eight cadaveric knee specimens were prepared by removing the skin and subcutaneous fat. The sartorius fascia was divided to allow clear identification of the medial ligamentous structures. Knees were then mounted in a custom-made rig and the quadriceps muscle and the iliotibial tract were loaded, using cables and hanging weights. Threads were mounted between tibial and femoral pins positioned in the anterior, middle, and posterior parts of the attachment sites of the native superficial medial collateral ligament (sMCL) and posterior oblique ligament (POL). Pins were also placed at the attachment sites relating to two commonly used medial reconstructions (Bosworth/Lind and LaPrade). Length changes between the tibiofemoral pin combinations were measured using a rotary encoder as the knee was flexed through an arc of 0-120°.

RESULTS

With knee flexion, the anterior fibres of the sMCL tightened (increased in length 7.4% ± 2.9%) whilst the posterior fibres slackened (decreased in length 8.3% ± 3.1%). All fibre regions of the POL displayed a uniform lengthening of approximately 25% between 0 and 120° knee flexion. The most isometric tibiofemoral combination was between pins placed representing the middle fibres of the sMCL (Length change = 5.4% ± 2.1% with knee flexion). The simulated sMCL reconstruction that produced the least length change was the Lind/Bosworth reconstruction with the tibial attachment at the insertion of the semitendinosus and the femoral attachment in the posterior part of the native sMCL attachment side (5.4 ± 2.2%). This appeared more isometric than using the attachment positions described for the LaPrade reconstruction (10.0 ± 4.8%).

CONCLUSION

The complex behaviour of the native MCL could not be imitated by a single point-to-point combination and surgeons should be aware that small changes in the femoral MCL graft attachment position will significantly effect graft length change patterns. Reconstructing the sMCL with a semitendinosus autograft, left attached distally to its tibial insertion, would appear to have a minimal effect on length change compared to detaching it and using the native tibial attachment site. A POL graft must always be tensioned near extension to avoid capturing the knee or graft failure.

Clinical outcomes of contemporary lateral augmentation techniques in primary ACL reconstruction: a systematic review and meta-analysis

PURPOSE

The purpose of this investigation was to systematically review the contemporary literature to determine if a lateral augmentation (LA) added to an Anterior Cruciate Ligament Reconstruction (ACLR) provides better clinical and patient reported outcomes compared to an isolated ACLR.

METHODS

A systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) criteria. Two authors independently conducted an electronic search using MEDLINE® and Embase® on February 6^th, 2021 for level I-III randomized controlled trials (RCT) and prospective cohort studies without randomization, published after 2012 and with a minimum of two year follow-up. Publications were included when they reported on the objective knee stability examination, patient reported outcome scores, return to sports or graft rupture rate of any type of primary, isolated ACLR compared to ACLR combined with any type of LA.

RESULTS

A total of 11 studies that reported on a combined total of 1892 unique patients were eligible for data extraction, including five RCTs and six prospective cohort studies. In 6 studies, an Anterolateral Ligament reconstruction (ALLR) was the LA of choice, while the 5 other publications used different types of Lateral Extra-articular Tenodesis (LET). A significant reduction in graft ruptures was found in patients treated with ACLR + LA (3%) compared to isolated ACLR (12%). Rotational laxity was significantly higher in isolated ACLR (14%) compared to ACLR + LA (6%). Addition of a LA reduced anterior translation when assessed via instrumented laxity testing. No significant difference was found in the patient reported outcome scores (IKDC and Tegner) between both patient groups, except for the Lysholm Score which was significant in favour of the ACLR + LA group.

CONCLUSION

Combination of a primary ACLR with a LA can significantly reduce the risk of graft rupture and provide better rotatory stability, without jeopardizing patient reported outcomes.

LEVEL OF EVIDENCE

Level III, Systematic Review of Level I, II and III studies.

[Effectiveness of double-bundle anterior cruciate ligament reconstruction combined with anterolateral ligament reconstruction for revision]

Objective

To investigate the effectiveness of double-bundle anterior cruciate ligament (ACL) reconstruction combined with anterolateral ligament (ALL) reconstruction in the treatment of revision patients with ACL graft failure.

Methods

Between January 2018 and June 2019, 15 patients underwent ACL revision with double-bundle ACL reconstruction combined with ALL reconstruction. There were 12 males and 3 females with an average age of 30.1 years (range, 17-49 years). The technique of primary ACL reconstruction included single-bundle reconstruction in 13 cases and double-bundle reconstruction in 2 cases. These reconstructions applied autografts in 14 cases and allograft in 1 case. The causes of ACL reconstruction failure were identified as traumatic rupture in 9 cases and non-traumatic failure in 6 cases, including 2 cases of graft absorption and 3 cases of graft laxity. The average time from the primary ACL reconstruction to revision was 28.5 months (range, 8-60 months). The subjective and objective indicators of knee joint function were compared before operation and at last follow-up to evaluate the effectiveness. The subjective indicators included International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner score. The objective indicators included anterior tibial translation (dynamic and static) and side-to-side difference (SSD), pivot-shift test, Lachman test, the difference of single-legged hop test, and the loss ratio of extensor muscle strength on the affected side.

Results

All incisions healed by first intetion, and no complications such as infection, venous thrombosis of lower extremity, or neurovascular injury occurred. All patients were followed up for an average of 19.1 months (range, 12-30 months). At last follow-up, all patients had returned to pre-injury sports level. The IKDC score, Lysholm score, and Tegner score were significantly improved ( P<0.05); anterior tibial translations (dynamic and static) significantly decreased when compared with preoperative one ( P<0.05) and returned to the physiological range. The SSD, Lachman test, pivot-shift test, the difference of single-legged hop test, and the loss ratio of extensor muscle strength on the affected side were significantly better than those before operation ( P<0.05).During the follow-up, there was no re-rupture of the graft, no stiffness of the knee joint and limitation of mobility; 1 case had a protruding femoral end compression screw, which was removed through the original incision under local anesthesia.

Conclusion

Double-bundle ACL reconstruction combined with ALL reconstruction can significantly improve the knee function in revision patients with ACL graft failure. It can reduce the anterior translation of tibia, and effectively prevent postoperative rotational instability of the knee.

Editorial Commentary: Lateral Extra-Articular Tenodesis Results in Better Stability After Anterior Cruciate Ligament Reconstruction for Patients With High-Grade Pivot Shifts

Magnetic resonance imaging of the torn anterior lateral ligament (ALL) is inconsistent and subject to significant intra- and interobserver variability. Like that of an anterior cruciate ligament (ACL), an ALL tear can vary in degree (first, second, or third) and location (tibial or femoral side). These variations may impact the appropriate surgical intervention. Relevant biomechanical data indicate that the deep iliotibial band fibers are more important than the ALL in controlling pivot shift. Lateral compartment overconstraint after ALL reconstruction does not appear to be a biomechanical or clinical issue. An ALL reconstruction creates a nonisometric construct (tight in extension and lax in flexion), allowing physiologic internal tibial rotation at 90° flexion, whereas lateral extra-articular tenodesis (LET) is more isometric, limiting physiologic internal tibial rotation at 90° flexion. The indications for a combined ACL/ALL reconstruction are evolving, but a Segond fracture and ligamentous hyperlaxity of ≥5 using the modified Beighton system seem reasonable. An ACL/LET reconstruction results in better stability for patients with high-grade pivot shifts.

Safe Femoral Fixation Depth and Orientation for Lateral Extra-Articular Tenodesis in Anterior Cruciate Ligament Reconstruction

Background:

Patients who undergo anterior cruciate ligament (ACL) reconstruction (ACLR) can have a persistent postoperative pivot shift. Performing lateral extra-articular tenodesis (LET) concurrently has been proposed to address this; however, LET femoral fixation may interfere with the ACLR femoral tunnel, which could damage the ACL graft or its fixation.

Purpose:

To evaluate the safe maximum implant or tunnel depth for a modified Lemaire LET when combined with ACLR anteromedial portal femoral tunnel drilling and to validate the safe LET drilling angles to avoid conflict with the ACLR femoral tunnel.

Study Design:

Descriptive laboratory study.

Methods:

Twelve fresh-frozen cadaveric knees were used. With each knee at 120° of flexion, an ACLR femoral tunnel in the anteromedial bundle position was created arthroscopically via the anteromedial portal using a 5-mm offset guide, a guide wire, and an 8-mm reamer, which was left in situ. A modified Lemaire LET was performed using a 1 cm-wide iliotibial band strip harvested with the distal attachment intact, to be fixed in the femur. The desired LET fixation point was identified with an external aperture 10 mm proximal and 5 mm posterior to the fibular collateral ligament’s femoral attachment, and a 2.4-mm guide wire was drilled, aiming at 0°, 10°, 20°, or 30° anteriorly in the axial plane and at 0°, 10°, or 20° proximally in the coronal plane (12 different drilling angle combinations). The relationship between the LET drilling guide wire and the ACLR femoral tunnel reamer was recorded for each combination. When a collision with the femoral tunnel was recorded, the LET wire depth was measured.

Results:

Collision with the ACLR femoral tunnel occurred at a mean LET wire depth of 23.6 mm (range, 15-33 mm). No correlation existed between LET wire depth and LET drilling orientation (r = 0.066; P = .67). Drilling angle in the axial plane was significantly associated with the occurrence of tunnel conflict (P < .001). However, no such association was detected when comparing the drilling angle in the coronal plane (P = .267).

Conclusion:

Conflict of LET femoral fixation with the ACLR femoral tunnel using anteromedial portal drilling occurred at a mean depth of 23.6 mm but also at a depth as little as 15 mm, which is shorter than most implants. When longer implants or tunnels are used, the orientation should be directed at least 30° anteriorly in the axial plane to minimize the risk of tunnel conflict, bearing in mind the risk of joint violation.

Clinical Relevance:

This study provides important information for surgeons performing LET in combination with ACLR anteromedial portal femoral tunnel drilling regarding safe femoral implant or tunnel length and orientation.

Combined Anterior and Anterolateral Stabilization of the Knee With the Hamstring Tendons

Anterior cruciate ligament reconstruction allows good control of sagittal laxity but insufficient rotary laxity control. Our objective is to describe an original lateral extra-articular tenodesis using gracilis in addition to an intra-articular reconstruction using the semitendinosus in a short 4-strand graft. The principles are as follows: The femoral tunnel for intra-articular and extra-articular reconstruction is unique, the femoral attachment is posterior and proximal to the lateral epicondyle, the graft is under the lateral collateral ligament, and the tibial insertion is isometric from 0° to 60° between the Gerdy tubercle and the fibular head.

The effect of anterolateral ligament reconstruction on knee constraint: A computer model-based simulation study

BACKGROUND

To determine the influence of anterolateral ligament reconstruction (ALLR) on knee constraint through the analysis of knee abduction (valgus) moment when the knee is subjected to external translational (anterior) or rotational (internal) loads.

METHODS

A knee computer model simulated from a three-dimensional computed tomography scan of healthy male was implemented for this study. Three groups were designed: (1) intact knee, (2) combined Anterior Cruciate Ligament (ACL) and Antero-Lateral Complex (ALC) deficient knee, and (3) combined ACL and Antero- lateral Ligament (ALL) reconstructed knee. The reconstructed knee group was subdivided into four groups according to attachment of reconstructed anterolateral ligament to the femoral epicondyle. Each group of simulated knees was placed at 0°, 10°, 20°, 30°, 40° and 50° of knee flexion. For each position an external anterior (drawer) 90-N force or a five-newton meter internal rotation moment was applied to the tibia. The interaction effect between the group of knees and knee flexion angle (0-50°) on knee kinematics and knee abduction moment under external loads was tested.

RESULTS

When reconstructed knees were subjected to a 90-N anterior force or a five-newton meter internal rotation moment there was significant reduction in anterior translation and internal rotation compared with deficient knees. Only the ALLR procedure using posterior and proximal femoral attachment sites for graft fixation combined with ACL reconstruction allowed similar mechanical behavior to that observed in the intact knee.

CONCLUSIONS

Combined ACL and ALLR using a minimally invasive method in an anatomically reproducible manner prevents excessive anterior translation and internal rotation. Using postero-proximal femoral attachment tunnel for reconstruction of ALL does not produce overconstraint of the lateral tibiofemoral compartment.

Editorial Commentary: Let's ALL Agree-Anterior Cruciate Ligament Reconstruction Outcomes Need to Be Improved and Extra-Articular Procedures Have an Essential Role

We are united as an orthopaedic community in trying to improve the outcomes of anterior cruciate ligament (ACL) reconstruction. Graft rupture rates of 10% to 28% are reported in high-risk populations, reoperation for non-graft rupture-related indications are reported in 18% to 26%, and only 50% to 65% of recreational athletes return to their preinjury level of sports. Numerous groups across the world have published studies providing evidence demonstrating significant clinical efficacy of lateral extra-articular tenodesis in improving the outcomes of ACL surgery. Finally, the reductions in ACL graft rupture rates augmented with anterolateral ligament or a modified Lemaire reconstruction appear to be broadly comparable. In our hands, anterolateral ligament may result in fewer adverse events.

The Role of the Posterolateral Tibial Slope in the Rotational Instability of the Knee in Patients Affected by a Complete Isolated Anterior Cruciate Ligament Injury: Its Value in the Decision-Making Process during the Anterolateral Ligament Reconstruction

Purpose  The aim of this retrospective, multicenter study was to investigate the correlation between a high degree of rotatory instability, posterolateral tibial slope (PLTS), and anterolateral ligament (ALL) injury. Methods  The study population consisted of 76 adults with isolated, complete noncontact anterior cruciate ligament (ACL) tear. The sample was divided into two groups according to the preoperative degree of rotator instability (group A: pivot-shift test grades 2 and 3; group B: pivot-shift test grade 1). Preoperative magnetic resonance imaging (MRI) assessment included angle of PLTS, posterior shift of the lateral femoral condyle (16 mm) on the tibial plateau, and the presence/absence of ALL injury. The two groups were compared for differences. Results  There was a statistically significant association between pivot-shift test grades 2 and 3 (group A), PLTS slope angle > 9 degrees, and ALL injury ( p  < 0.05). Group A also demonstrated a greater posterior shift of lateral femoral condyle (>11 mm), which was, however, not statistically significant when evaluated as an isolated variable. Conclusion  Our study indicates that an increased PLTS is associated with an increased incidence of ALL injury and an increased grade of pivot shift in patients with ACL tear. Assessment of posterolateral tibial slope on MRI can therefore play a key adjunct role in the surgical planning of ALL reconstruction, especially in cases when ALL damage is radiologically difficult to detect or doubtful. Level of Evidence  This is a retrospective comparative level III study.

[Research progress in anterolateral ligament of knee]

Objective

To review research progress in the anterolateral ligament (ALL) of knee, and provide a clinical reference for diagnosis and treatment of ALL injury.

Methods

The literature on the diagnosis and treatment of ALL injury was widely reviewed. The incidence, anatomy, biomechanics, injury mechanism, and treatment status of ALL were summarized.

Results

The ALL contributes to the effect of controlling the internal rotation and anterior translation of the tibia, which affects the axial migration of the knee. ALL injury can be diagnosed according to the signs and MRI examination. Currently, no consensus exists for the surgical indications of ALL injury, but most surgeons tend to perform ALL reconstruction in patients requiring anterior cruciate ligament (ACL) reconstruction or revision surgery with higher pivot-shift tests. At present, various techniques have been used for ALL reconstruction, and there is no optimal technique. In addition, the long-term effectiveness of ALL reconstruction is unclear due to the lack of high-quality studies and long-term postoperative follow-up.

Conclusion

The ALL contributes to maintaining knee stability, and the ALL reconstruction technique and its effectiveness still need further research.

The role of anterolateral augmentation in primary ACL reconstruction

The anterolateral soft tissue envelope of the knee has long been recognised as a key stabilising structure. Once the mainstay of operative management of anterior cruciate ligament (ACL) rupture, interest in the area fell away with the advent of intraarticular arthroscopic reconstruction. Renewed interest in these structures together with cadaveric data evidencing the potential for restoration of near normal knee biomechanics following ACL and anterolateral soft tissue reconstruction has driven current concepts and development of operative techniques. Options for current anterolateral augmentation techniques in primary ACL reconstruction plus patient selection considerations are reviewed, together with an outlook at future research key to development of this area.

Tactile techniques are associated with a high variability of tunnel positions in lateral extra-articular tenodesis procedures

INTRODUCTION

The purpose of this study was to determine the variability of femoral tunnel positions applying two different lateral extra-articular tenodesis (LET) techniques, guiding on the tactile identification (1) of the lateral epicondyle (Lemaire procedure) and (2) of the Kaplan fibre attachments on the distal femur (MacIntosh procedure) and to analyse whether one of these procedures is more suitable for reliable femoral tunnel positioning in LET procedures.

MATERIALS AND METHODS

Two experienced knee surgeons determined femoral tunnel positions in ten fresh-frozen cadaveric knee specimens according to the modified Lemaire and MacIntosh techniques. Tunnel positions were measured on true lateral radiographs as absolute distances from the posterior cortex line (anterior-posterior direction) and from a perpendicular line intersecting the contact of the posterior femoral condyle (proximal-distal direction), respectively. Further, tunnel positions were measured relatively to the femur height. An independent F test was used to compare variances between Lemaire and MacIntosh tunnel positions and between anterior-posterior and proximal-distal directions.

RESULTS

The mean Lemaire and MacIntosh positions were found 2.7 ± 5.5 mm and 3.6 ± 3.4 mm anterior to the posterior cortex line, and 7.5 ± 5.0 mm and 17.3 ± 6.9 mm proximal to the perpendicular line intersecting the contact of the posterior femoral condyle, respectively. Mean Lemaire and MacIntosh positions, relative to the femur height, were found at 8.8% and 10.9% (anterior-posterior) and 22.2% and 50.8% (proximal-distal), respectively. Variability in tunnel positioning was observed for both techniques, showing no significant differences in the variance (p > 0.05) and partially overlapping tunnel positions of both techniques. The overall variance of tunnel positions, however, was significantly greater in proximal-distal than in anterior-posterior direction (F = 2.673, p < 0.038).

CONCLUSIONS

Femoral tunnel positions in LET procedures have a high degree of variability and inaccuracy. Palpating anatomic landmarks appears to be insufficient to generate reproducible tunnel positions. Radiographic landmarks may enable more reproducible identification of isometric femoral tunnel positions and reduce malpositioning.

Length-change patterns of the medial collateral ligament and posterior oblique ligament in relation to their function and surgery

PURPOSE

To define the length-change patterns of the superficial medial collateral ligament (sMCL), deep MCL (dMCL), and posterior oblique ligament (POL) across knee flexion and with applied anterior and rotational loads, and to relate these findings to their functions in knee stability and to surgical repair or reconstruction.

METHODS

Ten cadaveric knees were mounted in a kinematics rig with loaded quadriceps, ITB, and hamstrings. Length changes of the anterior and posterior fibres of the sMCL, dMCL, and POL were recorded from 0° to 100° flexion by use of a linear displacement transducer and normalised to lengths at 0° flexion. Measurements were repeated with no external load, 90 N anterior draw force, and 5 Nm internal and 5 Nm external rotation torque applied.

RESULTS

The anterior sMCL lengthened with flexion (p < 0.01) and further lengthened by external rotation (p < 0.001). The posterior sMCL slackened with flexion (p < 0.001), but was lengthened by internal rotation (p < 0.05). External rotation lengthened the anterior dMCL fibres by 10% throughout flexion (p < 0.001). sMCL release allowed the dMCL to become taut with valgus rotation (p < 0.001). The anterior and posterior POL fibres slackened with flexion (p < 0.001), but were elongated by internal rotation (p < 0.001).

CONCLUSION

The structures of the medial ligament complex react differently to knee flexion and applied loads. Structures attaching posterior to the medial epicondyle are taut in extension, whereas the anterior sMCL, attaching anterior to the epicondyle, is tensioned during flexion. The anterior dMCL is elongated by external rotation. These data offer the basis for MCL repair and reconstruction techniques regarding graft positioning and tensioning.

ACL reconstruction combined with lateral monoloop tenodesis can restore intact knee laxity

PURPOSE

An anterior cruciate ligament (ACL) injury is often combined with injury to the lateral extra-articular structures, which may cause a combined anterior and rotational laxity. It was hypothesised that addition of a 'monoloop' lateral extra-articular tenodesis (mLET) to an ACL reconstruction would restore anteroposterior, internal rotation and pivot-shift laxities better than isolated ACL reconstruction in combined injuries.

METHOD

Twelve cadaveric knees were tested, using an optical tracking system to record the kinematics through 0°-100° of knee flexion with no load, anterior and posterior translational forces (90 N), internal and external rotational torques (5 Nm), and a combination of an anterior translational (90 N) plus internal rotational load (5 Nm). They were tested intact, after sectioning the ACL, sectioning anterolateral ligament (ALL), iliotibial band (ITB) graft harvest, releasing deep ITB fibres, hamstrings tendon ACL reconstruction, mLET combined with ACL reconstruction, and isolated mLET. Two-way repeated-measures ANOVA compared laxity data across knee states and flexion angles. When differences were found, paired t tests with Bonferroni correction were performed.

RESULTS

In the ACL-deficient knee, cutting the ALL significantly increased anterior laxity only at 20°-30°, and only significantly increased internal rotation at 50°. Additional deep ITB release significantly increased anterior laxity at 40°-90° and caused a large increase of internal rotation at 20°-100°. Isolated ACL reconstruction restored anterior drawer, but significant differences remained in internal rotation at 30°-100°. After adding an mLET there were no remaining differences with anterior translation or internal rotation compared to the intact knee. With the combined injury, isolated mLET allowed abnormal anterior translation and rotation to persist.

CONCLUSIONS

Cutting the deep fibres of the ITB caused large increases in tibial internal rotation laxity across the range of knee flexion, while cutting the ALL alone did not. With ACL deficiency combined with anterolateral deficiency, ACL reconstruction alone was insufficient to restore native knee rotational laxity. However, combining a 'monoloop' lateral extra-articular tenodesis with ACL reconstruction did restore native knee laxity.