Influence of the Anterolateral Ligament on Knee Laxity: A Biomechanical Cadaveric Study Measuring Knee Kinematics in 6 Degrees of Freedom Using Dynamic Radiostereometric Analysis

Dynamic radiostereometry can objectively quantify the kinematic laxity patterns and rotation instability of the knee during a pivot-shift test

PURPOSE

The pivot-shift test is used to clinically assess knee instability in patients with anterior cruciate ligament (ACL) lesions; however, it has low interobserver reliability. Dynamic radiostereometry (dRSA) is a highly precise and noninvasive method for the objective evaluation of joint kinematics. The purpose of this study was to quantify precise knee kinematics during a pivot-shift test using dRSA imaging.

METHOD

Eight human donor legs, including hemipelvises, were evaluated. Arthroscopic intervention was performed inducing ligament lesions in the ACL, and anterolateral ligament (ALL) section was performed as a capsular incision. The pivot-shift test was recorded with dRSA on knees with intact ligaments, ACL-deficient and ACL + ALL-deficient knees.

RESULTS

A pivot-shift pattern was identifiable after ligament lesion, as a change in tibial posterior drawer velocity from 7.8 mm/s (95% CI: 3.7; 11.9) in ligament intact knees to 30.4 mm/s (95% CI 23.0; 38.8) after ACL lesion to 35.1 mm/s (95% CI 23.4; 46.7) after combined ACL-ALL lesion. The anterior-posterior drawer excursion increased from 2.8 mm (95% CI 2.1; 3.4) in ligament intact knees to 7.2 mm (95% CI 5.5; 8.9) after ACL lesion to 7.6 mm (95% CI 5.5; 9.8) after combined lesion. A statistically significant increase in tibial external rotation towards the end of the pivot-shift motion was observed when progressing from intact to ACL + ALL-deficient knees (p < 0.023).

CONCLUSION

This experimental study demonstrates the feasibility of dRSA to objectively quantify the kinematic laxity patterns of the knee during the pivot-shift test. The dynamic parameters obtained through dRSA revealed the kinematic changes from ACL to combined ACL-ALL ligament lesion.

LEVEL OF EVIDENCE

Not applicable.

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.

Combined anterior cruciate ligament revision with reconstruction of the antero-lateral ligament does not improve outcome at 2-year follow-up compared to isolated acl revision; a randomized controlled trial

PURPOSE

It is essential to obtain rotational stability of the knee after anterior cruciate ligament reconstruction (ACL-R) and it is suggested that a supplementary reconstruction of the antero-lateral ligament (ALL-R) may supports this. Theoretically, ALL-R may be particularly advantageous to support revision of failed ACL-Rs. It was hypothesized that ACL revision combined with ALL-R will result in superior outcome compared to isolated ACL revision.

METHODS

The study was designed as a randomized controlled trial. Patients eligible for first time ACL revision were randomized to either isolated ACL revision (- ALL group) or ACL revision combined with a single-stranded allograft ALL-reconstruction (+ ALL group). Patient reported outcomes and function were evaluated at two-year follow-up by KNEES-ACL, KOOS, and Tegner activity scale. Objective knee laxity was evaluated at one-year follow-up using an instrumented Rolimeter test, the pivot shift test, and a manual Lachman test.

RESULTS

A total of 103 patients were enrolled with 49 patients randomized to the + ALL group and 54 patients in the - ALL group. There were no differences at baseline between groups regarding age, gender, body mass index, preoperative patient reported outcome scores and concomitant meniscus or cartilage injury. The ACL revision was performed with an allograft in 10 patients (20%) in the + ALL group and 8 patients (15%) in the -ALL group. At follow-up there was no significant difference between the groups in patient reported outcome scores and clinical knee laxity.

CONCLUSION

Supplementary ALL-R does not improve subjective outcome of first time ACL revision at two-years and clinical knee stability at one-year follow-up compared to isolated ACL revision.

LEVEL OF EVIDENCE

Level I.

Additional Anterolateral Ligament Reconstruction Helps Patients Improve Dynamic Postural Stability in Revision Anterior Cruciate Ligament Reconstruction

Background and Objectives: The goal in treating anterior cruciate ligament (ACL) injury especially in revision cases is return to sports activity by regaining dynamic postural stability. Among various methods to achieve this goal, additional anterolateral ligament reconstruction (ALLR) is gaining attention. The purpose of this study was to evaluate the effects of additional ALLR in revision ACL reconstruction (RACLR). Materials and Methods: Patients who underwent RACLR between July 2015 and June 2018 were enrolled. The exclusion criteria were less than 1-year follow-up, age older than 45 years, concomitant multiple ligament injuries, contralateral knee injury, subtotal or total meniscectomized state, and articular cartilage lesions worse than Outerbridge grade 3. Thirty-nine patients (20 patients; RACLR only (Group A), 19 patients; RACLR with additional ALLR (Group B)) were included. Clinical scores (Lysholm score, subjective International Knee Documentation Committee (IKDC) score, Tegner activity scale), isokinetic strength test, single-leg-hop for distance test (SLHDT), Y-balance test (YBT) were checked preoperatively and 1-year postoperatively. Results: Limb symmetry index values in YBT showed significantly better result in Group B 1-year postoperatively (Group A: 97.2 ± 4.0, Group B: 100.3 ± 2.9, p = 0.010), although there were no differences preoperatively between groups (Group A: 90.4 ± 6.7, Group B: 89.3 ± 5.5, p = 0.594). Regarding clinical scores, isokinetic strength tests, and SLHDT, there were no differences between groups preoperatively nor 1-year postoperatively. Conclusions: Additional ALLR in RACLR helped patients gain better dynamic postural stability at 1-year postoperative follow-up.

Sectioning of the Anterolateral Ligaments in Anterior Cruciate Ligament Sectioned Knees Increases Internal Rotation of the Knee Joint: A Systematic Review and Meta-analysis of Cadaveric Studies

PURPOSE

To investigate whether anterolateral ligament (ALL) sectioning (sALL) in the anterior cruciate ligament (ACL)-sectioned (sACL) knee increases the anterior tibial translation (ATT) or internal rotation (IR) of the knee from previous cadaveric biomechanical studies.

METHODS

Multiple comprehensive literature databases, including PubMed (MEDLINE), EMBASE, and Cochrane Library, were searched for studies evaluating the in vitro biomechanical function of ALL. This meta-analysis compared the increased ATT and IR between the sACL and sACL + sALL knees at 30°, 60°, and 90° of knee flexion. Thresholds of 2 mm for the difference in ATT and 2° for the difference in IR were considered to be clinically significant.

RESULTS

Thirteen cadaveric biomechanical studies were included. All 13 studies satisfied the threshold for a satisfactory methodological quality (Quality Appraisal for Cadaveric Studies score >75%). At 30° of knee flexion, the meta-analysis showed a greater increase in ATT in the sACL + sALL knees than in the sACL knees by 1.23 mm (95% confidence interval [CI], 0.62-1.84; P < .0001). However, the mean difference was less than the minimal clinically significant difference (<2 mm). The meta-analysis also showed a greater increase in IR in the sACL + sALL knees than in the sACL knees at 30° (mean difference [MD]: 2.24°; 95% CI: 1.39-3.09; P < .00001), 60° (MD: 2.77°; 95% CI: 1.88-3.67; P < .00001), and 90° (MD: 2.29°; 95% CI: 1.42-3.15; P < .00001) of knee flexion. The differences in IR at 30°, 60°, and 90° of knee flexion were clinically relevant (>2°).

CONCLUSIONS

Despite the different experimental setups and protocols between studies, the meta-analysis of biomechanical cadaveric studies showed that sectioning of the ALL in sACL knees increased IR at 30°, 60°, and 90° of knee flexion.

CLINICAL RELEVANCE

The results of this systematic review and meta-analysis suggest that ALL contributes to IR in ACL-deficient knees at 30°, 60°, and 90° of flexion.

Medial congruent polyethylene design show different tibiofemoral kinematics and enhanced congruency compared to a standard symmetrical cruciate retaining design for total knee arthroplasty-an in vivo randomized controlled study of gait using dynamic radiostereometry

PURPOSE

New total knee arthroplasty implant designs attempt to normalize kinematics patterns that may improve functional performance and patient satisfaction. It was hypothesized that a more medial congruent (MC) anatomic bearing design (1) influences the tibiofemoral kinematics and (2) enhances articular congruency compared to a standard symmetrical cruciate retaining (CR) bearing design.

METHODS

In this double-blinded randomized study, 66 patients with knee osteoarthritis were randomly included in two groups: MC (n = 31) and CR (n = 33). Clinical characteristics such as knee ligament lesions and knee osteoarthritis scores were graded on preoperative magnetic resonance imaging and radiography. At the 1-year follow-up, dynamic radiostereometric analysis was used to assess tibiofemoral joint kinematics and articulation congruency. Patient-reported outcome measures, Oxford Knee Score, the Forgotten Joint Score, and the Knee Osteoarthritis Outcome Score, were assessed preoperatively and at the 1-year follow-up.

RESULTS

Compared to the CR bearing, the MC bearing displayed an offset with approximately 3 mm greater anterior tibial drawer (p < 0.001) during the entire motion, and up to approximately 3.5 degrees more tibial external rotation (p = 0.004) from mid-swing to the end of the gait cycle at the 1-year follow-up. Furthermore, the congruency area in the joint articulation was larger during approximately 80% of the gait cycle for the MC bearing compared to the CR. The patient-reported outcome measures improved (p < 0.001), but there were no differences between groups. In addition, there were no differences in clinical characteristics and there were no knee revisions or recognized deep infections during follow-up.

CONCLUSION

The study demonstrates that the MC-bearing design changes tibiofemoral kinematics and increases the area of congruency towards more native knee kinematics than the CR bearing. In perspective this may contribute to a more stabilized knee motion, restoring the patient's confidence in knee function during daily activities.

Anterolateral ligament MRI of the knee in ACL injuries: MRI abnormalities association with instability

OBJECTIVE

To evaluate anterolateral ligament abnormalities (ALL) at MRI scans and correlate with data from clinical instability tests (Lachman and pivot shift) performed under anesthesia in patients with acute anterior cruciate ligament (ACL) tears. Furthermore, perform multivariate analysis with other variables to isolate the ALL contribution to instability from other abnormalities.

METHODS

Retrospective analysis of MRI and instability tests of 95 patients with ACL tears. The ALL was classified as no abnormality, abnormality without discontinuity, and discontinuity. Injuries in other knee ligament structures and menisci were also assessed. Results of instability tests (pivot shift and Lachman) with the patient anesthetized for arthroscopic ACL reconstruction were obtained from the patient database. Statistical analysis was performed using the IBM SPSS 22.

RESULTS

ALL abnormalities and iliotibial band (ITB), lateral (LCL), and medial (MCL) collateral ligament injuries showed a statistically significant correlation with the pivot shift test. The ALL MRI abnormalities were associated with the high-grade pivot shift results (p < 0.0005), with an odds ratio of 55.9 for high degrees of pivot shift in patients with abnormal ALL. The logistic model for all variables analyzed with the results of the pivot shift test demonstrated that the ALL was the only variable with a statistically significant correlation in the model (p < 0.0005).

CONCLUSION

MRI ALL abnormalities in patients with ACL injuries have a significant association with pivot shift test results in patients under anesthesia. The logistic model for high - grade pivot shift test results demonstrated that ALL abnormalities were the only variable with significant correlation.

KEY POINTS

• Evaluating the anterolateral ligament with MRI in acute anterior cruciate ligament injuries is useful to predict higher grades of pivot shift test in the moment of the arthroscopic reconstruction. • An abnormal anterolateral ligament presented an odds ratio of 55 for high degrees of pivot shift. • ALL MRI abnormalities association with knee instability is independent from other internal knee injuries.

Development, construction, and validation of a thinner uniplanar calibration cage for radiostereometry

Radiostereometric analysis (RSA) is an accurate and precise radiographic method that can be used to measure micromotion of implants and study joint kinematics in vivo. A calibration cage with radiopaque markers is used to calibrate the RSA images; however, the thickness (250 mm) of the calibration cage restricts the available area for the patient and equipment during RSA recordings. A thinner calibration cage would increase the recording area, facilitate handling of the cage, and ease integration of the cage with the RSA system. We developed a thinner calibration cage without compromise of accuracy and precision. First, we performed numerical simulations of an RSA system, and showed that the calibration cage thickness could be decreased to 140 mm maintaining accuracy and precision using 40 fiducial and 30 control markers. Second, we constructed a new calibration cage (NRT cage) according to the simulation results. Third, we validated the new calibration cage against two state-of-the-art calibration cages (Umeaa cage and Leiden cage) in a phantom study. All cages performed similar for marker-based analysis, except for y-rotation, where the Umeaa cage (SD = 0.064 mm) was less precise compared to the NRT (SD = 0.038 mm) and Leiden cages (0.042 mm) (p = .01). For model-based analysis the NRT cage had superior precision for translations (SD ≤ 0.054 mm) over the Leiden cage (SD ≤ 0.118 mm) and Umeaa cage (SD ≤ 0.093 mm) (p < .01). The combined study confirmed that the new and thinner calibration cage maintained accuracy and precision at the level of existing thicker calibration cages.

Postural control during single leg stance in individuals with clinical indication for combined reconstruction of the anterior cruciate and the anterolateral ligaments of the knee: a cross-sectional study

Background

Several studies have shown persistent postural control deficits and rotatory instability in patients after isolated Anterior Cruciate Ligament (ACL) reconstruction. There is evidence to support that the Anterolateral Ligament (ALL) plays an important role in the remaining anterolateral rotatory laxity of the knee. There are no further evidences in order to understand how patients with a combined ACL + ALL reconstruction surgery indication behave regarding postural control. The aim of this cross-sectional study was to assess if patients with a clinical indication for the combined ACL + ALL surgery showed a deficient postural control in single leg stance compared to subjects with a regular ACL reconstruction indication and to a control group.

Methods

An assessment of static postural control on single leg stance was performed on a force plate, with eyes open and closed, and the center of pressure (COP) displacement variables were analyzed: maximum and mean amplitude in anteroposterior (AP) and in mediolateral (ML) direction; mean velocity of displacement and area of displacement. Eighty-nine male individuals participated and were divided into 3 groups: ACL Group, ACL + ALL Group and Control Group.

Results

The ACL+ ALL Group showed significantly greater COP displacement in most variables in the injured leg for the eyes closed test, compared to the ACL Group, as detailed: Total ML displacement (9.8 ± 6.77 vs. 13.98 ± 6.64, p < 0.001); Mean ML displacement (2.58 ± 2.02 vs. 3.72 ± 1.99, p < 0.001); Total AP displacement (9.5 ± 3.97 vs. 11.7 ± 3.66, p = 0.001); Mean AP displacement (1.77 ± 0.87 vs. 2.27 ± 0.86, p = 0.001); Area of displacement (111.44 ± 127.3 vs. 183.69 ± 131.48, p < 0.001).

Conclusion

Subjects with a clinical indication for ACL + ALL combined reconstruction surgery showed increased COP displacement compared to patients with indication for an ACL isolated reconstruction surgery.

Patients with knee osteoarthritis can be divided into subgroups based on tibiofemoral joint kinematics of gait - an exploratory and dynamic radiostereometric study

OBJECTIVE

Patients with advanced knee osteoarthritis (KOA) frequently alter their gait patterns in an attempt to alleviate symptoms. Understanding the underlying pathomechanics and identifying KOA phenotypes are essential to improve treatments. We investigated kinematics in patients with KOA to identify subgroups of homogeneous knee joint kinematics.

METHOD

A total of 66 patients with symptomatic KOA scheduled for total knee arthroplasty and 15 age-matched healthy volunteers with asymptomatic, non-arthritic knees were included. We used k-means clustering to divide patients into subgroups based on dynamic radiostereometry-assessed tibiofemoral joint kinematics. Clinical characteristics such as knee ligament lesions and KOA scores were graded by magnetic resonance imaging and radiographs, respectively.

RESULTS

We identified four clusters that were supported by clinical characteristics. The flexion group (n = 20) consisted primarily of patients with medial KOA. The abduction group (n = 17) consisted primarily of patients with lateral KOA. The anterior draw group (n = 10) was composed of patients with medial KOA, some degree of anterior cruciate ligament lesion and the highest KOA score. The external rotation group (n = 19) primarily included patients with medial collateral and posterior cruciate ligament lesions.

CONCLUSION

Based on tibiofemoral gait patterns, patients with advanced KOA can be divided into four subgroups with specific clinical characteristics and different KOA-affected compartments. The findings add to our understanding of how knee kinematics may affect the patient's development of different types of KOA. This may inspire improved and more patient-specific treatment strategies in the future.

Laxity measurement of internal knee rotation after primary anterior cruciate ligament rupture versus rerupture

PURPOSE

The aim of the current study was to objectify the rotational laxity after primary anterior cruciate ligament (ACL) rupture and rerupture after ACL reconstruction by instrumented measurement. It was hypothesized that knees with recurrent instability feature a higher internal rotation laxity as compared to knees with a primary rupture of the native ACL.

STUDY DESIGN

Cross-sectional study, Level of evidence III.

METHODS

In a clinical cross-sectional study successive patients with primary ACL rupture and rerupture after ACL reconstruction were evaluated clinically and by instrumented measurement of the rotational and antero-posterior laxity with a validated instrument and the KT1000^®, respectively. Clinical examination comprised IKDC 2000 forms, Lysholm Score, and Tegner Activity Scale. Power calculation and statistical analysis were performed (p value < 0.05).

RESULTS

24 patients with primary ACL rupture and 23 patients with ACL rerupture were included. There was no significant side-to-side difference in anterior translation. A side-to side difference of internal rotational laxity ≥ 10° was found significantly more frequent in reruptures (53.6%) compared to primary ruptures (19.4%; p < 0.001). A highly significant relationship between the extent of the pivot-shift phenomenon and side-to-side difference of internal rotation laxity could be demonstrated (p < 0.001). IKDC 2000 subjective revealed significantly better scores in patients with primary ACL tear compared to patients with ACL rerupture (56.4 ± 7.8 vs. 50.8 ± 6.2; p = 0.01). Patients with primary ACL tears scored significantly better on the Tegner Activity Scale (p = 0.02). No significant differences were seen in the Lysholm Score (p = 0.78).

CONCLUSION

Patients with ACL rerupture feature significantly higher internal rotation laxity of the knee compared to primary ACL rupture. The extend of rotational laxity can be quantified by instrumented measurements. This can be valuable data for the indication of an anterolateral ligament reconstruction in ACL revision surgery.

Anterolateral Ligament Reconstruction Improves Anteroposterior Stability As Well As Rotational Stability in Revision Anterior Cruciate Ligament Reconstruction with High-Grade Pivot Shift

This study aimed to investigate the effect of anterolateral ligament reconstruction (ALLR) in revision anterior cruciate ligament reconstruction (ACLR) with high-grade pivot shift. The hypothesis was that revision ACLR combined with ALLR (RACLR with ALLR group) would show superior clinical outcomes to those of isolated revision ACLR. We retrospectively evaluated consecutive patients who underwent revision ACLR (RACLR) combined with ALLR between October 2015 and January 2017. The indication for combination of ALLR with revision ACLR was failed ACLR with ≥G2 pivot-shift instability. The control group included patients who underwent isolated revision ACLR (isolated RACLR group) for the same indication between July 2013 and September 2015. Exclusion criteria were ≤G1 pivot-shift instability, multiple ligament reconstruction, bilateral ligament injury, double-bundle reconstruction, insufficient medical records, postoperative infection, and follow-up loss at postoperative 2 years. Clinical scores, stability tests, and failure rates were compared between groups at the 2-year follow-up. The RACLR with ALLR group had 18 patients (mean age, 32.9 ± 10.8 years) and the RACLR group had 21 patients (mean age, 29.6 ± 10.2 years). Clinical scores at the 2-year follow-up showed no significant differences between groups. However, the RACLR with ALLR group showed better stability in the Lachman test (p = 0.005), pivot-shift test (p = 0.030), and side-to-side difference in stress radiographs (3.9 ± 3.0 mm vs. 5.9 ± 2.8 mm, p = 0.018) than the isolated RACLR group. The RACLR with ALLR group had two failures (11.1%), and the RACLR group had three failures (14.3%). In conclusion, ALLR in revision ACLR with high-grade pivot shift improves anteroposterior stability as well as rotational stability at 2-year follow-up. Therefore, ALLR is recommended with revision ACLR, especially in patients with high-grade pivot shift. This is a Level III, retrospective cohort review.

Combined Anterolateral and Anterior Cruciate Ligament Reconstruction Improves Pivot Shift Compared With Isolated Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis of Randomized Controlled Trials

PURPOSE

To perform a systematic review and meta-analysis of the literature on anterolateral ligament (ALL) reconstruction as it relates to techniques, biomechanical properties, and clinical outcomes.

METHODS

PubMed, OVID/Medline, and Embase were queried in July 2020. Data pertaining to (1) techniques, (2) biomechanical properties, and (3) clinical outcomes of ALL reconstruction were recorded. DerSimonian-Laird random-effects meta-analyses were performed for included randomized controlled trials comparing combined ALL/anterior cruciate ligament (ACL) reconstruction and isolated ACL reconstruction. Data from lower levels of evidence were described qualitatively, and when possible, outcomes were reported as ranges to avoid inappropriate pooling of data.

RESULTS

A total of 46 articles were identified. Sixteen were biomechanical studies, 16 were clinical outcome studies, and 14 were technique studies. Of the 16 biomechanical studies, the majority demonstrated that anterior translation, internal rotation, and pivot shift was restored with combined ACL/ALL reconstruction and superior to ACL reconstruction alone. Ten biomechanical studies reported on constraint: 4 noted overconstraint when the femoral attachment site was proximal and posterior to the lateral femoral condyle, whereas 1 reported laxity. ACL failure rates after combined ACL/ALL reconstruction ranged between 2.7% and 11.1%. The mean postoperative Lysholm score ranged between 58.7 and 98.0; mean postoperative International Knee Documentation Committee score between 57.8 and 96.3; and mean postoperative Tegner score between 4 and 8. Six outcomes were explored through meta-analysis, of which the mean difference in Lysholm scores (2.26, P < .001) and restoration of pivot shift (relative risk 1.1, P = .046) was found to favor combined ACL/ALL reconstruction.

CONCLUSIONS

Although indications for ALL reconstruction remain heterogeneous, contemporary evidence suggests that ALL reconstruction improves pivot shift and confers comparable clinical and functional outcomes with isolated ACLR.

LEVEL OF EVIDENCE

IV, systematic review and meta-analysis.

Biomechanical Effects of Combined Anterior Cruciate Ligament Reconstruction and Anterolateral Ligament Reconstruction: A Systematic Review and Meta-analysis

Background:

Combined anterior cruciate ligament (ACL) reconstruction (ACLR) and anterolateral ligament reconstruction (ALLR) are performed with the intention to restore native knee kinematics after ACL tears. There continue to be varying results as to the difference in kinematics between combined and isolated procedures, including anterior tibial translation (ATT) and internal tibial rotation (IR).

Purpose:

To perform a systematic review and meta-analysis to evaluate the kinematic changes of a combined ACLR/ALLR versus isolated ACLR and to assess the effects of different fixation techniques.

Study Design:

Systematic review.

Methods:

We conducted a systematic review and meta-analysis of 15 human cadaveric biomechanical studies evaluating combined ACLR/ALLR versus isolated ACLR and their effects on ATT and IR in 149 specimens. The primary outcomes were ATT and IR. Secondary outcomes included graft type and size as well as fixation methods such as type, angle, tension, and position of fixation. Meta-regression was used to examine the effect of various cofactors on the resulting measures.

Results:

Compared with isolated ACLR, combined ACLR/ALLR decreased ATT and IR by 0.01 mm (95% CI, –0.059 to 0.079 mm; P = .777) and 1.64° (95% CI, 1.30°-1.98°; P < .001), respectively. Regarding ACLR/ALLR, increasing the knee flexion angle and applied IR force led to a significant reduction in IR (P < .001 and P = .044, respectively). There was also a significant reduction in IR in combined procedures with semitendinosus ALL graft, higher flexion fixation angles, and tension but no change in IR with differing femoral fixation points (P < .001, P < .001, and P = .268, respectively). Multivariate meta-regression showed that the use of tibial-sided suture anchor fixation significantly reduced IR (P < .001).

Conclusion:

These results suggest that a combined ACLR/ALLR procedure significantly decreases IR compared with isolated ACLR, especially at higher knee flexion angles. Semitendinosus ALL graft, fixation at higher knee flexion, increased tensioning, and tibial-sided interference screw fixation in ALLR may help to further reduce IR.

Anterolateral ligament reconstruction improves the clinical and functional outcomes of anterior cruciate ligament reconstruction in athletes

PURPOSE

To compare the outcomes of anterior cruciate ligament (ACL) reconstruction with those of combined ACL and anterolateral ligament (ALL) reconstruction in ACL-deficient knees. The objective of this study was to improve knowledge regarding the treatment of ACL-deficient knees with combined ACL and ALL reconstruction. Combined ACL and ALL reconstruction has been hypothesized to result in better clinical and functional outcomes than isolated ACL reconstruction (ACLR).

METHODS

One-hundred and seven adult male athletes with ACL tears and high-grade pivot shifts were randomized into two groups. Those in group A (n = 54) underwent ACLR, while those in group B (n = 53) underwent combined ACL and ALL reconstruction. The median age was 26 (18-40) and 24 (18-33) years in groups A and B, respectively, and the median follow-up was 60 (55-65) months. Physical examination findings, instrumented knee laxity tested using a KT-1000 arthrometer, and International Knee Documentation Committee Scale (IKDC) scores were used to evaluate the outcomes.

RESULTS

One-hundred and two patients were available for follow-up: 52 in group A and 50 in group B. Postoperatively, the pivot shift was normal in 43 (82.7%) and 48 (96%) patients in groups A and B, respectively (p < 0.001). The median instrumented knee laxity was 2.5 ± 0.7 (1.2-6.1) mm in patients in group A and 1.2 ± 0.7 (1.2-3.2) mm in patients in group B (p < 0.001). Additionally, 44 (84.6%) patients in group A had normal IKDC scores and 3 (5.8%) had nearly normal scores, while 48 (96.0%) patients in group B had normal IKDC scores and 2 (4%) had nearly normal scores (p < 0.001).

CONCLUSION

Combined ACL and ALL reconstruction, compared with isolated ACLR resulted in favourable clinical and functional outcomes, as demonstrated by decreased rotational instability and instrumented knee laxity, a lower graft rupture rate and better postoperative IKDC scores.

LEVEL OF EVIDENCE

1.

Assessment of knee kinematics with dynamic radiostereometry: Validation of an automated model-based method of analysis using bone models

Radiostereometic analysis (RSA) is a precise method for the functional assessment of joint kinematics. Traditionally, the method is based on tracking of surgically implanted bone markers and analysis is user intensive. We propose an automated method of analysis based on models generated from computed tomography (CT) scans and digitally reconstructed radiographs. The study investigates method agreement between marker-based RSA and the CT bone model-based RSA method for assessment of knee joint kinematics in an experimental setup. Eight cadaveric specimens were prepared with bone markers and bone volume models were generated from CT-scans. Using a mobile fixture setup, dynamic RSA recordings were obtained during a knee flexion exercise in two unique radiographic setups, uniplanar and biplanar. The method agreement between marker-based and CT bone model-based RSA methods was compared using bias and LoA. Results obtained from uniplanar and biplanar recordings were compared and the influence of radiographic setup was considered for clinical relevance. The automated method had a bias of -0.19 mm and 0.11° and LoA within ±0.42 mm and ±0.33° for knee joint translations and rotations, respectively. The model pose estimation of the tibial bone was more precise than the femoral bone. The radiographic setup had no clinically relevant effect on results. In conclusion, the automated CT bone model-based RSA method had a clinical precision comparable to that of marker-based RSA. The automated method is non-invasive, fast, and clinically applicable for functional assessment of knee kinematics and pathomechanics in patients.

Knee laxity, lateral meniscus tear and distal femur morphology influence pivot shift test grade in ACL injury patients

PURPOSE

Although several factors have been considered to be associated with pivot shift test grade in ACL injured patients, a conclusion regarding which factors contribute to the pivot shift test grade has not been reached. The purpose of this study was to identify factors associated with preoperative pivot shift test grade.

METHODS

Three hundred and sixty-six consecutive patients who underwent ACL reconstruction in our hospital were enrolled in the study. Patients were divided into two groups on the basis of preoperative pivot shift test grade (Mild: grade 0-3, Severe: grade 4-6). First, 13 independent variables (age, gender, period from injury to surgery, hyperextension, KT measurement, contralateral side pivot shift test grade, medial and lateral tibial slope, lateral condyle length, lateral condyle height, distal femoral condyle offset, medial and lateral meniscus tear) were analyzed by one-way ANOVA and Chi-squared test. Binary Logistic regression was then performed based on the results of univariate analyses (independent variables of p < 0.2 were included).

RESULTS

Hyperextension, lateral meniscus tear, contralateral side pivot shift test grade, distal femoral condyle offset and KT measurement were identified as risk factors for preoperative pivot shift grade via logistic regression analysis.

CONCLUSION

The current study revealed that hyperextension, lateral meniscus tear, contralateral side pivot shift test grade, distal femoral condyle offset and anterior instability were associated with preoperative pivot shift grade. Patients with above factors that cannot be modified during surgery may need special consideration when ACL reconstruction is performed, as greater preoperative pivot shift has been proven to be a risk factor for residual pivot shift after ACL reconstruction.

LEVEL OF EVIDENCE

III.

Calcaneal cuboid joint motion and osteotomy stability in children one year after calcaneal lengthening osteotomy

Introduction

Flexible pes planovalgus in children may be corrected with a calcaneal lengthening osteotomy (CLO).However, CLO surgery may displace the distal calcaneal fragment dorsally and affect the motion in the calcaneal-cuboid joint (CCJ). We used radiostereometric analysis (RSA) to evaluate CCJ motion and CLO stability in children one year after CLO.

Methods

Ten patients (10 feet) with symptomatic flexible pes planovalgus were investigated one year after CLO. Mean age was 11.5 years (range 8.2-14.2). Standardised RSA measurements of the foot were obtained one year after surgery without and with weight-bearing (single leg stance). Tantalum markers inserted during surgery, were used to described the CCJ motion as cuboid bone motion with respect to the distal calcaneus, and the CLO stability as distal calcaneal migration with respect to the proximal calcaneus.

Results

One year after surgery the CLO was stable. The motion in the CCJ upon full weight-bearing was mean -1.04 mm (CI95% -1.40; -0.67) joint distraction, mean 2.27 mm (CI95% 1.57; 2.96) cuboid dorsal translation, mean -1.94 mm (CI 95% -2.68; -1.20) cuboid medial translation, and mean 7.43° (CI 95% 3.97; 10.88) adduction.

Conclusion

The motion in the CCJ of children with CLO corrections for pes planovalgus is similar to that of adults during stance load with a normal foot posture and the patients were asymptomatic. Marker-based RSA may be used to evaluate causalities of foot symptoms after CLO surgery.

The Anterolateral Ligament of the Knee

The femoral attachment of the anterolateral ligament (ALL) of the knee is still under debate, but the tibial attachment is consistently between Gerdy's tubercle and the fibular head. The structure is less identifiable and more variable in younger patients. The ALL likely plays a role in rotational stability, but its impact on anterior stability is less clear. Numerous ALL reconstruction techniques have been described. Biomechanical analysis of these techniques has not shown clear benefits, but this literature is limited by the heterogeneity of techniques, graft choices, and study methodology. Clinical studies of combined anterior cruciate ligament (ACL) and ALL reconstruction are few but promising in lowering the risk of an ACL reinjury. To our knowledge, there are no studies showing the clinical outcomes of combined ACL and ALL reconstruction in pediatric patients, who are at higher risk for ACL graft failure than adults.

A phantom and cadaveric study of radiostereometric analysis in posterior cervical and lumbar spinal fusion

BACKGROUND CONTEXT

Detecting pseudarthrosis following spinal fusion is important for accurate diagnosis and treatment. Current diagnostic measures hold certain drawbacks. Radiostereometric analysis (RSA) is a radiographic technique with the capability to measure intervertebral segment changes and may be a novel way of assessing fusion.

PURPOSE

The purpose of this work was to measure the accuracy and precision of RSA in instrumented posterior cervical and lumbar spinal fusion for measuring intervertebral movement. Further, to gain surgical practice with RSA in spine and determine optimal bead placements.

STUDY DESIGN

Artificial bone and cadaveric spine models were used to simulate a 3-level cervical (C3-C6) and a 2-level (L4-S1) lumbosacral posterior spinal fusion to analyze bead placements and to measure RSA accuracy and precision.

METHODS

Preliminary RSA bead placements were planned and measured in the artificial model. Secondary bead placements were adjusted slightly in the cadaveric model to consider additional fusion scenarios. Bead spread, detectability, and stability were measured to determine optimal placements. Translational and rotational precision of both models were measured. Accuracy was measured in the artificial spine model. Model-based RSA software was used for analysis.

RESULTS

Optimal bead placements were found to be throughout the lateral mass of C3-C6 and in the spinous process, transverse process, and within the screw canal of L4-S1. Detectability was high among all segments. Spread was greater in L4-S1 than C3-C6 due to bead collinearity along the transverse axis of the cervical vertebrae. Translational and rotational RSA accuracy in cervical and lumbosacral regions ranged between 0.005 to 0.014 mm and 0.058 to 0.208°. Translational and rotational precision measured in the phantom models ranged 0.017 to 0.131 mm and 0.058 to 0.394° in C3-C6, and 0.086 to 0.191 mm and 0.200 to 0.369° in L4-S1. Translational and rotational precision measured in the cadaveric models ranged 0.054 to 0.548 mm and 0.148 to 1.386° in C3-C6, and 0.068 to 0.164 mm and 0.100 to 0.270° in L4-S1.

CONCLUSIONS

RSA was found to be a feasible radiographic technique in C3-C6 and L4-S1 spinal fusion when measured in artificial and cadaveric models. Optimal bead placements were determined. Bead spread was shown to be better throughout the lumbar region than the cervical region due to anatomical size variations. RSA accuracy and precision were within acceptable RSA criteria.

CLINICAL SIGNIFICANCE

The results from this work contribute to the accuracy, precision, and bead placements for studying RSA in cervical and lumbar spinal fusions. This work may further support the development of clinical studies to assess spinal fusion by evaluating postoperative intervertebral movement using RSA.

Anterolateral Ligament Reconstruction and Modified Lemaire Lateral Extra-Articular Tenodesis Similarly Improve Knee Stability After Anterior Cruciate Ligament Reconstruction: A Biomechanical Study

PURPOSE

To determine the stabilizing role of anterolateral ligament reconstruction (ALLR) and modified Lemaire lateral extra-articular tenodesis (LET) performed in combination with anterior cruciate ligament reconstruction (ACLR) and to determine whether either procedure was superior to the other.

METHODS

Six nonpaired, human, fresh-frozen cadaveric knees were tested with a 6-df robotic system. Internal rotation and anterior translation of the knee were recorded from 0° to 90° of flexion after application of a 5-Nm internal rotation torque and a 134-N anterior load, respectively. A full kinematic assessment was performed in each of the following conditions: (1) intact knee, (2) after sectioning of the anterior cruciate ligament (ACL), (3) after sectioning of the ACL and anterolateral ligament, (4) after isolated ACLR, and (5) after combined ACLR and Lemaire LET and combined ACLR and ALLR. ALLR was performed using the gracilis tendon, whereas the modified Lemaire procedure was performed using the central strip of the iliotibial band. The different states were compared using a Tukey paired comparison test.

RESULTS

In knees with combined deficiency of the ACL and anterolateral structures, anterior translation and internal rotation remained significantly increased after isolated ACLR compared with the intact knee (+2.33 ± 1.44 mm and +1.98° ± 1.06°, respectively; P < .01). On the other hand, the addition of ALLR or modified Lemaire LET to ACLR restored anterior translation and internal rotation to values similar to those in the intact knee. The 2 anterolateral procedures did not show statistically significantly different values for both tests. This difference was 0.67 ± 1.46 mm for anterior translation (P = .79) and 0.11° ± 1.11° for internal rotation (P = .99).

CONCLUSIONS

In knees with ACL and anterolateral deficiency, combined ACLR and anterolateral reconstruction restored the native knee stability in anterior translation and internal rotation contrary to isolated ACLR. In addition, both types of extra-articular reconstruction-ALLR and modified Lemaire LET-were similar in terms of restoring knee kinematics, and neither overconstrained the knee.

CLINICAL RELEVANCE

In knees with deficiency of the ACL and anterolateral structures, combined ACLR and anterolateral reconstruction increased knee stability at time zero after surgery. This biomechanical improvement could be responsible for the protective effect on ACL graft and meniscal repair reported in the literature after the combined procedure.

Anterolateral ligament reconstruction as an augmented procedure for double-bundle anterior cruciate ligament reconstruction restores rotational stability: Quantitative evaluation of the pivot shift test using an inertial sensor

PURPOSE

The purpose of this study was to investigate the biomechanical function of the anterolateral structures (ALS) of the knee regarding rotational stability, and to attempt to verify the effectiveness of anterolateral ligament (ALL) reconstruction concomitant with double-bundle anterior cruciate ligament (ACL) reconstruction by quantifying the pivot shift test (PST) using an inertial sensor.

METHODS

Six knees of the fresh-frozen cadavers were evaluated during the following phases: (1) [Intact]; (2) ACL-deficient [ACL-D]; (3) ACL-reconstructed [ACL-R]; (4) ACL-reconstructed + ALS-deficient [ACL-R + ALS-D]; and (5) combined ACL and ALL reconstructed [ACL-R + ALL-R]. We evaluated knee rotational instability during each phase using the PST. We used an inertial sensor to calculate tibial external rotational angular velocity (ERAV) and tibial acceleration. Data were analyzed using repeated-measures analysis of variance; statistical significance was accepted as P < 0.05.

RESULTS

Relative to [Intact], [ACL-D] caused a significant increase in ERAV and acceleration. However, there was no difference in these parameters between [ACL-R] and [Intact]. [ACL-R + ALS-D] increased ERAV significantly compared with [ACL-R], and there was a significant difference between ERAV during [ACL-R + ALS-D] and [Intact]. However, ERAV was significantly reduced during [ACL-R + ALL-R] compared with [ACL-R + ALS-D], and there was no significant difference in ERAV or acceleration between [ACL-R + ALL-R] and [Intact].

CONCLUSIONS

ALS controlled rotational instability in cooperation with the ACL in a cadaveric model. In cases of combined injury of ACL and ALS, concomitant ACL and ALL reconstruction may restore knee stability comparable with the intact state.

A Biomechanical Study of the Role of the Anterolateral Ligament and the Deep Iliotibial Band for Control of a Simulated Pivot Shift With Comparison of Minimally Invasive Extra-articular Anterolateral Tendon Graft Reconstruction Versus Modified Lemaire Reconstruction After Anterior Cruciate Ligament Reconstruction

PURPOSE

To determine whether the deep fibers of the iliotibial band (dITB) or the anterolateral ligament (ALL) provides more control of a simulated pivot shift and whether a minimally invasive anterolateral reconstruction (ALR) designed to functionally restore the ALL and dITB is mechanically equivalent to a modified Lemaire reconstruction (MLR).

METHODS

Six matched pairs of cadaveric knees (N = 12) were subjected to a simulated pivot shift to evaluate anteroposterior translation; internal rotation; and valgus laxity at 0°, 30°, and 90° of flexion. The anterior cruciate ligament (ACL) was sectioned in all specimens, and retesting was performed. Within each pair, sequential sectioning of the ALL and dITB was performed, followed by testing; the contralateral knee was sectioned in reverse order. Knees underwent ACL reconstruction (ACLR) and repeat testing. Then, MLR (n = 6) or ALR (n = 6) was performed on matched pairs for final testing.

RESULTS

Sectioning of the dITB versus ALL (after ACL sectioning) produced significantly more anterior translation at all flexion angles (P = .004, P = .012, and P = .011 for 0°, 30°, and 90°, respectively). The ACL-plus-dITB sectioned state had significantly more internal rotation at 0° versus ACL plus ALL (P = .03). ACLR plus ALR restored native anterior translation at all flexion angles. ACLR plus MLR restored anterior translation to native values only at 0° (P = .34). We found no statistically significant differences between ACLR plus ALR and ACLR plus MLR at any flexion angle for internal rotation or valgus laxity compared with the native state.

CONCLUSIONS

ALR of the knee in conjunction with ACLR can return the knee to its native biomechanical state without causing overconstraint. The dITB plays a more critical role in controlling anterior translation and internal rotation at 0° than the ALL. The minimally invasive ALR was functionally equivalent to MLR for restoration of knee kinematics after ACLR.

CLINICAL RELEVANCE

The dITB is more important than the ALL for control of the pivot shift. A minimally invasive extra-articular tendon allograft reconstruction was biomechanically equivalent to a modified Lemaire procedure for control of a simulated pivot shift.