Anterior cruciate ligament reconstruction with lateral extra-articular tenodesis reduces knee rotation laxity and graft failure rate: A systematic review and meta-analysis

Overconstraint Associated With a Modified Lemaire Lateral Extra-Articular Tenodesis Is Decreased by Using an Anterior Femoral Insertion Point in a Cadaveric Model

PURPOSE

To investigate tibiofemoral knee kinematics when shifting the femoral insertion point of the modified Lemaire lateral extra-articular tenodesis (LET) anterior to the lateral epicondyle.

METHODS

Six fresh-frozen human knee joints were tested on a test bench in the following states: (1) native, (2) anterolateral insufficient, (3) original Lemaire (oLET; insertion point: 4 mm posterior and 8 mm proximal to the epicondyle), (4) anterior Lemaire (aLET; insertion point: 5 mm anterior and 5 mm proximal to the epicondyle). Internal tibial rotation was statically investigated under an internal tibial torque of 5 Nm in 0°, 30°, 60°, and 90° of flexion. Anterior translation was statically investigated during a simulated Lachman test with an anterior translational force of 98 N. Additionally, the range of internal tibial rotation and anterior translation were dynamically investigated by a simulated pivot-shift test. Tibiofemoral kinematics were measured using an optical 3D motion analysis system.

RESULTS

The aLET showed an internal tibial rotation comparable to the native state for all tested flexion angles except 90° (0°: P = .201; 30°: P = .118; 60°: P = .126; 90°: P = .026). The oLET showed an internal tibial rotation below the values of the native state for all tested flexion angles indicating an overconstraint (0°: P = .003; 30°: P = .009; 60°: P = .029; 90°: P = .029). Direct comparisons between aLET and oLET showed a significantly decreased overconstraint at 0° and 30° of flexion (P = .001 and P = .003, respectively) when using the aLET. No differences in anterior translation and internal tibial rotation were found between the oLET and aLET during simulated Lachman and pivot-shift test (P > .05), approximating the native state.

CONCLUSIONS

An anteriorly shifted LET insertion point restored internal tibial rotation after anterolateral insufficiency to the native state while decreasing the overconstraint of internal tibial rotation induced by an LET using the originally described insertion point for small flexion angles ≤30°.

CLINICAL RELEVANCE

Using an LET insertion point anterior to the epicondyle was recently reported to lower the risk of tunnel interference and has now been shown to restore internal tibial rotation effectively in vitro in the course of the present study. Concerns of overconstraining internal tibial rotation are not diminished by this technique, but using an anterior insertion point helps to decrease overconstraint.

Combined Anterior Cruciate Ligament Reconstruction (ACLR) and Lateral Extra-articular Tenodesis through the Modified Lemaire Technique versus Isolated ACLR: A Meta-analysis of Clinical Outcomes

Objective  Lateral extra-articular tenodesis (LET) has been proposed to resolve rotatory instability following anterior cruciate ligament reconstruction (ACLR). The present meta-analysis aimed to compare the clinical outcomes of ACLR and ACLR with LET using the modified Lemaire technique. Materials and Methods  We performed a meta-analysis following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) staement. The literature search was performed on the PubMed, EBSCOHost, Scopus, ScienceDirect, and WileyOnline databases. The data extracted from the studies included were the study characteristics, the failure rate (graft or clinical failure) as the primary outcome, and the functional score as the secondary outcome. Comparisons were made between the patients who underwent isolated ACLR (ACLR group) and those submitted to ACLR and LET through the modified Lemaire technique (ACLR + LET group). Results  A total of 5 studies including 797 patients were evaluated. The ACLR + LET group presented a lower risk of failure and lower rate of rerupture than the ACLR group (risk ratio [RR] = 0.44; 95% confidence interval [95%CI]: 0.26 to 0.75; I 2  = 9%; p  = 0.003). The ACLR + LET group presented higher scores on the Knee Injury and Osteoarthritis Outcome Score (KOOS) regarding the following outcomes: pain, activities of daily living (ADL), sports, and quality of life (QOL), with mean differences of 0.20 (95%CI: 0.10 to 0.30; I 2  = 0%; p  < 0.0001), -0.20 (95%CI: -0.26 to -0.13; I 2  = 0%; p  < 0.00001), 0.20 (95%CI: 0.02 to 0.38; I 2  = 0%; p  = 0.03), and 0.50 (95%CI: 0.29 to 0.71; I 2  = 0%; p  < 0.00001) respectively when compared with the ACLR group. Conclusion  Adding LET through the modified Lemaire technique to ACLR may improve knee stability because of the lower rate of graft rerupture and the superiority in terms of clinical outcomes. Level of Evidence  I.

Internal Rotation Measurement of the Knee with Polymer-Based Capacitive Strain Gauges versus Mechanical Rotation Measurement Taking Gender Differences into Account: A Comparative Analysis

With the conventional mechanical rotation measurement of joints, only static measurements are possible with the patient at rest. In the future, it would be interesting to carry out dynamic rotation measurements, for example, when walking or participating in sports. Therefore, a measurement method with an elastic polymer-based capacitive measuring system was developed and validated. In our system, the measurement setup was comprised of a capacitive strain gauge made from a polymer, which was connected to a flexible printed circuit board. The electronics integrated into the printed circuit board allowed data acquisition and transmission. As the sensor strip was elongated, it caused a change in the spacing between the strain gauge's electrodes, leading to a modification in capacitance. Consequently, this alteration in capacitance enabled the measurement of strain. The measurement system was affixed to the knee by adhering the sensor to the skin in alignment with the anterolateral ligament (ALL), allowing the lower part of the sensor (made of silicone) and the circuit board to be in direct contact with the knee's surface. It is important to note that the sensor should be attached without any prior stretching. To validate the system, an in vivo test was conducted on 10 healthy volunteers. The dorsiflexion of the ankle was set at 2 Nm using a torque meter to eliminate any rotational laxity in the ankle. A strain gauge sensor was affixed to the Gerdii's tubercle along the course of the anterolateral ligament, just beneath the lateral epicondyle of the thigh. In three successive measurements, the internal rotation of the foot and, consequently, the lower leg was quantified with a 2 Nm torque. The alteration in the stretch mark's length was then compared to the measured internal rotation angle using the static measuring device. A statistically significant difference between genders emerged in the internal rotation range of the knee (p = 0.003), with female participants displaying a greater range of rotation compared to their male counterparts. The polymer-based capacitive strain gauge exhibited consistent linearity across all measurements, remaining within the sensor's initial 20% strain range. The comparison between length change and the knee's internal rotation angle revealed a positive correlation (r = 1, p < 0.01). The current study shows that elastic polymer-based capacitive strain gauges are a reliable instrument for the internal rotation measurement of the knee. This will allow dynamic measurements in the future under many different settings. In addition, significant gender differences in the internal rotation angle were seen.

Anterolateral augmentation procedures during anterior cruciate ligament reconstructions in skeletally immature patients: Scoping review of surgical techniques and outcomes

Purpose

Graft failure rates after anterior cruciate ligament reconstruction (ACLR) in children and adolescents are higher compared to adults. Anterolateral augmentation procedures have recently generated increased focus regarding their ability to reduce graft failure rates. Concerns in skeletally immatures are potential growth disturbances and overconstraint after anterolateral augmentation. The aim of this scoping review is to provide an overview of all current anterolateral augmentation procedures in skeletally immature patients and to discuss surgical techniques, clinical and biomechanical outcomes.

Methods

This scoping review was performed following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) statement extension for scoping reviews. On 22 December 2022, an information specialist performed a systematic literature search in Cochrane, PubMed (Medline) and EMBASE databases. Inclusion criteria were anterolateral augmentation procedures, including lateral extra-articular tenodesis (LET) and anterolateral ligament reconstruction (ALLR), in combination with ACLR in skeletally immatures.

Results

Twenty studies were included after screening 1.485 abstracts. Seventeen studies describe LET techniques, four studies ALLR techniques and one study both techniques. Biomechanical data is scarce and shows conflicting results. Two studies compared ACLR with LET to ACLR in skeletally immatures with promising results in favour of the combined procedure. There were no differences in outcomes between LET and ALLR.

Conclusions

Several LET and ALLR techniques have been described for skeletally immature patients and the first clinical data on LET and ALLR is available, which showed promising results. Further research is necessary to evaluate the risk of growth disturbances and overconstraint in skeletally immatures.

Level of Evidence

Level IV.

Digital measurement of anterolateral knee laxity using strain sensors

PURPOSE

The ambition of the research group was to develop a sensor-based system that allowed the transfer of results with strain sensors applied to the knee joint. This system was to be validated in comparison to the current static mechanical measurement system. For this purpose, the internal rotation laxity of the knee joint was measured, as it is relevant for anterolateral knee laxity and anterior cruciate ligament (ACL) injury.

METHODS

This is a noninvasive measurement method using strain sensors which are applied to the skin in the course of the anterolateral ligament. The subjects were placed in supine position. First the left and then the right leg were clinically examined sequentially and documented by means of an examination form. 11 subjects aged 21 to 45 years, 5 women and 6 men were examined. Internal rotation of the lower leg was performed with a torque of 2 Nm at a knee flexion angle of 30°.

RESULTS

Comparison of correlation between length change and internal knee rotation angle showed a strong positive correlation (r = 1, p < 0.01). Whereas females showed a significant higher laxity vs. males (p = 0.003).

CONCLUSIONS

The present study showed that the capacitive strain sensors can be used for reproducible measurement of anterolateral knee laxity. In contrast to the previous static systems, a dynamic measurement will be possible by this method in the future.

Overview of the anterolateral complex of the knee

In the last few years, much more information on the anterolateral complex of the knee has become available. It has now been demonstrated how it works in conjunction with the anterior cruciate ligament (ACL) controlling anterolateral rotatory laxity. Biomechanical studies have shown that the anterolateral complex (ALC) has a role as a secondary stabilizer to the ACL in opposing anterior tibial translation and internal tibial rotation. It is of utmost importance that surgeons comprehend the intricate anatomy of the entire anterolateral aspect of the knee. Although most studies have only focused on the anterolateral ligament (ALL), the ALC of the knee consists of a functional unit formed by the layers of the iliotibial band combined with the anterolateral joint capsule. Considerable interest has also been given to imaging evaluation using magnetic resonance and several studies have targeted the evaluation of the ALC in the setting of ACL injury. Results are inconsistent with a lack of association between magnetic resonance imaging evidence of injury and clinical findings. Isolated ACL reconstruction may not always reestablish knee rotatory stability in patients with associated ALC injury. In such cases, additional procedures, such as anterolateral reconstruction or lateral tenodesis, may be indicated. There are several techniques available for ALL reconstruction. Graft options include the iliotibial band, gracilis or semitendinosus tendon autograft, or allograft.