Effects of Anterolateral Structure Augmentation on the In Vivo Kinematics of Anterior Cruciate Ligament-Reconstructed Knees

Anatomic double-bundle transtibial anterior cruciate ligament reconstruction restores graft length changes but leads to larger graft bending angles

PURPOSE

The purpose of this study was to evaluate the femoral tunnel position using a modified anatomic transtibial (TT) double-bundle anterior cruciate ligament reconstruction (DBACLR) and to investigate the knee kinematics, graft length and graft bending angle following DBACLR.

METHODS

Ten patients who underwent DBACLR using the modified TT technique were included in the study. All patients performed a single-legged lunge under a dual fluoroscopic imaging system to assess the 6 degrees of freedom tibiofemoral kinematics. Femoral tunnel position was evaluated via postoperative three-dimensional (3D) computed tomography. The area centroids of anteromedial (AM) and posterolateral (PL) bundles were determined on 3D knee models. The lengths of AM and PL bundles, as well as graft bending angle at the femoral tunnel aperture, were measured by created virtual fibres.

RESULTS

The reconstructed knee rotated more externally compared with the contralateral knee between 0° and 60° (p ≤ 0.049). There is no significant difference in the length change of AM bundle (n.s.) and PL bundle (n.s.) between the two sides from 0° to 120° during the lunge motion. The maximum graft bending angle at the femoral tunnel aperture occurred at 0° of knee flexion, with the AM graft bending angle was 72.6° ± 9.0° and the PL graft bending angle was 90.3° ± 9.7°.

CONCLUSION

The modified TT technique used in this study could achieve anatomical ACL reconstruction, restoring graft length change patterns compared to contralateral knees. However, residual rotational instability of the reconstructed knee was observed after DBACLR, despite achieving anatomic tunnel placement. Therefore, double-bundle reconstruction may not sufficiently address the persistent rotational instability of the knee. Additionally, larger graft bending angles at the femoral tunnel aperture were found with the modified TT technique. Therefore, further improvement to the TT technique should focus on reducing the graft's curvature while maintaining the anatomical properties of the knee joint. The findings of this study highlight the need for improved surgical techniques to address residual rotational instability and optimise graft curvature. These improvements are crucial for enhancing patient outcomes and long-term joint function following ACL reconstruction.

LEVELS OF EVIDENCE

Level II.

Radiographic Incidence of Knee Osteoarthritis After Isolated ACL Reconstruction Versus Combined ACL and ALL Reconstruction: A Prospective Matched Study From the SANTI Study Group

BACKGROUND

Combined anterior cruciate ligament (ACL) reconstruction (ACLR) and anterolateral ligament reconstruction (ALLR) have demonstrated reduced risk of graft rerupture as compared with isolated ACLR. However, concerns remain that the risk of osteoarthritis (OA) may be increased by the addition of ALLR.

PURPOSE/HYPOTHESIS

The aim of this study was to evaluate the incidence of OA with isolated ACLR in comparison with ACLR + ALLR at medium-term follow-up. We hypothesized that there would be no differences between the groups.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients who underwent ACLR + ALLR with hamstring tendon autograft between January 2011 and March 2012 were propensity matched to patients who underwent isolated ACLR with bone-patellar tendon-bone (BPTB) or hamstring tendon autograft in the same period. Medium-term radiographic evaluation was performed using the International Knee Documentation Committee (IKDC) radiographic OA grading scale, modified Kellgren-Lawrence grade, and the surface fit method to assess percentage of joint space narrowing. Clinical outcomes were assessed with the following measures: IKDC, Knee injury and Osteoarthritis Outcome Score (KOOS), Lysholm, Tegner, and ACL Return to Sport after Injury.

RESULTS

A total of 80 patients (42 ACLR + ALLR and 38 isolated ACLR) were analyzed with a mean follow-up of 104 months. There was no significant difference between groups for joint space narrowing in the medial or lateral tibiofemoral or lateral patellofemoral (PF) compartment. However, 36.8% in the isolated ACLR group versus 11.9% in the ACLR + ALLR group had narrowing of the medial PF compartment (P = .0118). A lateral meniscal tear increased the risk of lateral tibiofemoral narrowing by nearly 5 times (odds ratio, 4.9; 95% CI, 1.547-19.367; P = .0123). The risk of medial PF narrowing was >4-fold with an isolated ACLR (odds ratio, 4.8; 95% CI, 1.44-19.05; P = .0179). Between the isolated ACLR group and the ACLR + ALLR group, the secondary meniscectomy rate was 13.2% versus 11.9% (not significantly different). There was no difference between groups in KOOS, Tegner, or IKDC scores. There was also no difference between groups for grades of osteoarthritic change for any classification system. Patients who received a BPTB graft had medial PF joint narrowing in 66.7% of cases as compared with 11.9% in those who received ACLR + ALLR (P = 0.118).

CONCLUSION

ACLR + ALLR did not increase the risk of OA in the lateral tibiofemoral compartment when compared with an isolated ACLR at medium-term follow-up. Isolated ACLR using BPTB was associated with a significantly increased risk of medial PF joint space narrowing.

REGISTRATION

NCT05123456 (ClinicalTrials.gov identifier).

Larger Medial Contact Area and More Anterior Contact Position in Medial-Pivot than Posterior-Stabilized Total Knee Arthroplasty during In-Vivo Lunge Activity

This study aimed to compare the in-vivo kinematics and articular contact status between medial-pivot total knee arthroplasty (MP-TKA) and posterior stabilized (PS) TKA during weight-bearing single-leg lunge. 16 MP-TKA and 12 PS-TKA patients performed bilateral single-leg lunges under dual fluoroscopy surveillance to determine the in-vivo six degrees-of-freedom knee kinematics. The closest point between the surface models of the femoral condyle and the polyethylene insert was used to determine the contact position and area. The nonparametric statistics analysis was performed to test the symmetry of the kinematics between MP-TKA and PS-TKA. PS-TKA demonstrated a significantly greater range of AP translation than MP-TKA during high flexion (p = 0.0002). Both groups showed a significantly greater range of lateral compartment posterior translation with medial pivot rotation. The contact points of PS-TKA were located significantly more posterior than MP-TKA in both medial (10°–100°) and lateral (5°–40°, 55°–100°) compartments (p < 0.0500). MP-TKA had a significantly larger contact area in the medial compartment than in the lateral compartment. In contrast, no significant differences were observed in PS-TKA. The present study revealed no significant differences in clinical outcomes between the MP and PS groups. The PS-TKA demonstrated significantly more posterior translations than MP-TKA at high flexion. The contact points are located more posteriorly in PS-TKA compared with MP-TKA. A larger contact area and medial pivot pattern during high flexion in MP-TKA indicated that MP-TKA provides enhanced medial pivot rotation.

Risk Factors for Anterior Cruciate Ligament Graft Failure in Professional Athletes: An Analysis of 342 Patients With a Mean Follow-up of 100 Months From the SANTI Study Group

BACKGROUND

Anterior cruciate ligament (ACL) injuries are among the most common knee injuries sustained in elite sport, and athletes generally undergo ACL reconstruction (ACLR) to facilitate their return to sport. ACL graft rupture is a career-threatening event for elite athletes.

PURPOSE/HYPOTHESIS

The purpose of this study was to determine the risk factors for graft failure in professional athletes undergoing ACLR. It was hypothesized that athletes who underwent combined ACLR with a lateral extra-articular procedure (LEAP) would experience significantly lower rates of graft rupture in comparison with those who underwent isolated ACLR.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Professional athletes who underwent primary ACLR with a minimum follow-up of 2 years were identified from the Santy database. Patients were excluded if they underwent major concomitant procedures, including multiligament reconstruction surgery or osteotomy. Further ipsilateral knee injury, contralateral knee injury, and any other reoperations or complications after the index procedure were identified by interrogation of the database and review of the medical notes.

RESULTS

A total of 342 athletes with a mean follow-up of 100.2 ± 51.9 months (range, 24-215 months) were analyzed. Graft failures totaling 31 (9.1%) were reported, requiring revision surgery because of symptomatic instability. The rate of graft failure was significantly higher when ACLR was not combined with a LEAP (15.5% vs 6.0%; P = .0105) and in athletes aged 21 years or younger (13.8% vs 6.6%; P = .0290). A multivariate analysis was performed using the Cox model and demonstrated that athletes undergoing an isolated ACLR were at >2-fold risk of ACL graft rupture (hazard ratio [HR], 2.678 [1.173; 4.837], P = .0164) when compared with those undergoing a combined ACLR with a LEAP. Additionally, athletes aged ≤21 years were also at >2-fold risk of graft failure (HR, 2.381 [1.313; 5.463]; P = .0068) than those aged >21 years. Sex, sport, and graft type were not found to be significant risk factors for graft failure.

CONCLUSION

Professional athletes undergoing isolated ACLR and aged ≤21 years are at >2-fold greater risk of graft failure. Orthopaedic surgeons treating elite athletes should combine an ACLR with a LEAP to improve ACL graft survivorship.

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.

Effect of Anterolateral Structure Augmentation on Graft Maturity After Anterior Cruciate Ligament Reconstruction: A Clinical and MRI Follow-up of 2 Years

BACKGROUND

Anterolateral structure augmentation (ALSA) has been applied to prevent residual rotatory instability and lower clinical failure rates after anterior cruciate ligament (ACL) reconstruction (ACLR); however, the effect of combined ALSA on the maturity of ACL grafts remains unknown.

PURPOSE

To evaluate the graft maturity and patient-reported outcomes in patients who underwent double-bundle ACLR with or without ALSA.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 92 patients who underwent double-bundle ACLR between January 2016 and July 2019 were included in the present study-44 patients with isolated ACLR (ACLR group) and 48 patients with combined ACLR and ALSA (ALSA group). Demographic characteristics, intraoperative findings, and patient-reported outcomes were prospectively collected. On postoperative magnetic resonance imaging at the 2-year follow-up, the signal-to-noise quotient (SNQ) values were separately calculated for 6 sections of the ACL graft, including the femoral intratunnel graft (FTG), intra-articular graft (IAG), and tibial intratunnel graft (TTG) of the anteromedial bundle (AMB) and the posterolateral bundle (PLB). Superior graft maturity was usually indicated by lower SNQ values.

RESULTS

The rates of return to preinjury sports were 47.9% and 27.3% in the ALSA and ACLR groups, respectively (difference, 20.6% [95% CI, 1.3%-40%]; P = .042). The AMB demonstrated significantly lower SNQ values in the ALSA group than in the ACLR group (FTG, 7.04 ± 3.65 vs 9.44 ± 4.51 [P = .006]; IAG, 6.62 ± 4.19 vs 8.77 ± 5.92 [P = .046]; TTG, 6.93 ± 3.82 vs 8.75 ± 4.55 [P = .040]). The SNQ values were significantly lower in the ALSA group for 2 of the 3 sections of the PLB (IAG, 7.73 ± 4.61 vs 9.88 ± 5.61 [P = .047]; TTG, 5.88 ± 3.10 vs 8.57 ± 4.32 [P = .001]). Partial lateral meniscectomy was correlated with higher SNQ values of the TTG in the AMB (β = 0.27; P = .009) and the PLB (β = 0.25; P = .008), with both groups pooled. Higher body mass index, smaller ACL graft-Blumensaat line angles, larger AMB graft diameters, and lower postoperative Tegner scores were also associated with inferior maturity in specific regions of the ACL graft.

CONCLUSION

A combination of ACLR and ALSA is a desirable option to improve the maturity of ACL grafts for patients who are young or expected to return to pivoting sports. Meanwhile, further investigations with higher levels of evidence and longer periods of follow-up are warranted.

Augmentation of Anterolateral Structures of the Knee Causes Undesirable Tibiofemoral Cartilage Contact in Double-Bundle Anterior Cruciate Ligament Reconstruction-A Randomized In-Vivo Biomechanics Study

PURPOSE

To analyze the in vivo tibiofemoral cartilage contact patterns in knees undergoing double-bundle anterior cruciate ligament reconstruction(DB-ACLR) with or without anterolateral structure augmentation (ALSA).

METHODS

Twenty patients with an ACL-ruptured knee and a healthy contralateral side were included. Nine patients received an isolated DB-ACLR (DB-ACLR group), and 11 patients had a DB-ACLR with ALSA (DB+ALSA group). At 1-year follow-up, a combined computed tomography, magnetic resonance imaging, and dual fluoroscopy imaging system analysis was used to capture a single-legged lunge of both the operated and healthy contralateral side. Tibiofemoral contact points (CPs) of the medial and lateral compartments were compared. CP locations were expressed as anteroposterior (AP, +/-) and medial-lateral (ML, -/+) values according to the tibia.

RESULTS

In the DB-ACLR knees, no significant differences were found in CPs when compared with the healthy contralateral knees (P ≥ .31). However, in the DB+ALSA knees, the CPs in the lateral compartment had a significantly more anterior (mean AP: operative, -2.8 mm, 95% confidence interval [CI] -5.0 to-0.7 vs healthy, -5.0 mm, 95% CI -6.7 to -3.2; P = .006) and lateral (mean ML: operative, 23.2 mm, 95% CI 21.9-24.5 vs healthy, 21.8 mm, 95% CI 20.2-23.3; P = .013) location. The CPs in the medial compartment were located significantly more posterior (mean AP: operative, -3.4, 95% CI -5.0 to -1.9 vs healthy, -1.3, 95% CI -2.6 to -0.1; P = .006) and lateral (mean ML: operative, -21.3, 95% CI -22.6 to -20.0 vs healthy, -22.6, 95% CI -24.2 to -21.0; P = .021).

CONCLUSIONS

DB-ACLR restored the tibiofemoral cartilage contact mechanics to near-normal values at 1-year follow-up. Adding the ALSA to the DB-ACLR resulted in significantly altered tibiofemoral cartilage contact locations in both the medial and lateral compartments.

CLINICAL RELEVANCE

In DB-ACLR knees, the addition of an ALSA may be unfavorable as it caused significantly changed arthrokinematics.

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.

Lateral-extra articular tenodesis vs. anterolateral ligament reconstruction in skeletally immature patients undergoing anterior cruciate ligament reconstruction

PURPOSE OF REVIEW

The aim of this study was to review the most recent available evidence about lateral-extra articular tenodesis (LET) and anterolateral ligament (ALL) reconstruction in young patients treated for anterior cruciate ligament (ACL) injury.

RECENT FINDINGS

The ALL of the knee acts as a secondary stabilizer of the knee preventing anterior translation and internal rotation. In vitro and in vivo biomechanical studies as well as prospective clinical trials have shown the importance of the ALL in knee biomechanics. The ALL injury has a synergetic impact on the knee stability in patients with acute ACL injury. ALL augmentation of ACL provides reduction of knee instability and graft failure and higher return to sport rates in high-risk patients. It has not been demonstrated that extra-articular procedures increase the risk of knee osteoarthritis secondary to knee over-constriction. Both Iliotibial band (ITB) ALL reconstruction and modified Lemaire LET have been shown safe and effective. Minimal biomechanical or clinical differences have been found between the two reconstruction methods.

SUMMARY

Young patients with ACL tears and risk factors such as laxity or pivot shift willing to return to sports may benefit from ALL augmentation. Therefore, it is essential to identify these high-risk patients to individualize treatment.

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.

Three-in-One Procedure for Revision ACL Reconstruction

Revision anterior cruciate ligament (ACL) reconstruction is a challenge due to the unfavorable condition of the knee and the lack of autogenous graft tissue. Anterolateral structure (ALS) reconstruction of the knee has been proved effective to address the unfavorable condition in revision cases, and lateral extra-articular tenodesis (LET) is a special technique that can enhance anterolateral stability of the knee without graft tissue. We introduce a procedure that combines ACL and ALS reconstruction, as well as LET for failed ACL reconstruction. The critical point of this technique is using the anterior half of the iliotibial band to realize LET and to partially reconstruct the ACL. Our clinical experience indicates this technique is extremely useful in revision ACL reconstruction without enough free graft tissue. This technique will provide a reasonable choice in revision ACL reconstruction.