Association Between Radiological Evidence of Kaplan Fiber Injury, Intraoperative Findings, and Pivot-Shift Grade in the Setting of Acute Anterior Cruciate Ligament Injury

Injuries to both anterolateral ligament and Kaplan fiber of the iliotibial band do not increase preoperative pivot-shift phenomenon in ACL injury

Background

To assess the incidence of anterolateral ligament (ALL) and Kaplan fiber of the iliotibial band (KF) injuries in patients with acute anterior cruciate ligament (ACL) injury on magnetic resonance imaging (MRI), and to investigate the association between these injuries and the magnitude of preoperative pivot-shift test.

Method

One-hundred and five patients with primary ACL injury were retrospectively reviewed. ALL injury and KF injury were assessed by preoperative MRI, and subjects were allocated into four groups: Group A, neither injury; Group B, only ALL injury; Group C, only KF injury; Group D, simultaneous ALL and KF injuries. Before ACL reconstruction, tibial acceleration during the pivot-shift test was measured by an electromagnetic measurement system, and manual grading was recorded according to the International Knee Documentation Committee (IKDC) guideline.

Results

In MRI, the ALL was identified in 104 patients (99.1%) and KF in 99 patients (94.3%). ALL and KF injuries were observed in 43 patients (43.9%) and 23 patients (23.5%), respectively. Patient distribution to each group was as follows; Group A: 43 patients (43.9%), Group B: 32 patients (32.7%), Group C: 12 patients (12.2%), Group D: 11 patients (11.2%). No significant differences were observed in tibial acceleration, and manual grading among the four groups.

Conclusion

Simultaneous injury to both ALL and KF was uncommon, and preoperative pivot-shift phenomenon did not increase even in those patients. The finding suggests that the role of ALL and KF in controlling anterolateral rotatory knee laxity may be less evident in the clinical setting compared to a biomechanical test setting.

Does an early post traumatic knee brace reduce the incidence of knee rotational instability?

PURPOSE

Several anterolateral stabilization procedures have been developed recently to address rotational instability of the knee. Currently, these procedures tend to be systematically used by some practitioners. However, antero-lateral structures of the knee (including the anterolateral ligament, ALL) have a self-healing potential which can reduce the need to perform an antero-lateral procedure. In this study, it was hypothesized that early post-traumatic immobilization of the knee with a knee brace would allow partial healing of antero-lateral structures and also allow control of the pivot shift, thus avoiding antero-lateral extra-articular stabilization. The objective of this study was to compare the severity of pivot shift between two groups of patients who all experienced anterior cruciate ligament (ACL) tear and respectively underwent post-traumatic immobilization of the knee versus no immobilization.

METHODS

This was a comparative, multicentric (three centers' study) retrospective, consecutive study including 168 patients who underwent ACL reconstruction between May and September 2022. The application or not of post-traumatic immobilization and its duration, the severity of pivot shift observed in the operating room under general anesthesia, the presence of anterolateral lesions as revealed by MRI and the patients' pre-injury sport activity were recorded.

RESULTS

A grade 3 pivot shift was found in 44 patients (27%). It was more frequently observed in the group without a brace compared to the group with a knee brace (18 patients out of 36: 50% versus 26 patients out of 132: 19.7%; p = 0.0012). Wearing a brace, whether hinged (OR = 0.221, [0.070-0.652]; p = 0.006) or not (OR = 0.232, [0.076-0.667]; p = 0.0064), was protective from the risk of developing a significant pivot shift.

CONCLUSION

This study demonstrated that the presence of pivot-shift was lower in the patients that had an early post-injury knee brace before their ACL reconstruction. Based on this result, systematic brace placement could be advocated for in patients after knee trauma.

LEVEL OF EVIDENCE

III, prognostic retrospective case-control study.

Anterolateral Ligament and Kaplan Fiber Injury Both Occur Frequently in Acute Anterior Cruciate Ligament-Injured Knees

BACKGROUND AND OBJECTIVES

The association of ALL and KF injuries in anterior cruciate ligament (ACL)-deficient knees remain topics of conflicting research despite improved magnetic resonance imaging (MRI). We aimed to evaluate the rate of the anterolateral ligament (ALL) and Kaplan fibers (KF) injuries in adults with acute ACL injuries using MRI.

METHODS

We retrospectively reviewed 64 patients with clinical and MRI diagnoses of acute ACL tears. Two radiologists analyzed and categorized the status of the ALL and KF in all patients as intact, partially injured, or completely injured. Interobserver agreement was assessed. Injuries to the collateral ligaments, ITB and posterior cruciate ligament (PCL) were also evaluated.

RESULTS

The mean age of the patients was 33 years. ALL injuries were observed in 46 (71%) patients, among whom 33 (71%) had partial and 13 (28%) had complete injuries. KF injuries were identified in 32 (50%) patients, with 28 (87.5%) of them having partial and 4 (12.5%) having complete injuries. Combined injuries of both ALL and KF were found in 25 (32.4%) patients (p-value of 0.266). The agreement between the examiners ranged from moderate to substantial (Kappa between 0.55 and 0.75), with the highest agreement observed in cases of KF injuries (Kappa = 0.75).

CONCLUSIONS

ALL and KF injuries were prevalent in acute ACL-injured knees with rates of injury of 71% and 50%, respectively. ALL injuries were more frequent and more frequently severe compared to KF injuries.

Combined anterolateral complex and anterior cruciate ligament injury: Anatomy, biomechanics, and management-State-of-the-art

Anterior cruciate ligament (ACL) rupture typically occurs because of sudden axial loading of the knee in conjunction with a coupled valgus and rotational moment about the tibia. However, the ACL is not the only structure damaged during this mechanism of injury, and studies have shown that the anterolateral complex (ALC) of the knee is also commonly involved. Biomechanical studies have established that the ALC plays an important role as a secondary stabiliser to control anterolateral rotatory laxity (ALRL). Indeed, it has been suggested that failure to address injury to the ALC at the time of ACL reconstruction (ACLR) may increase the risk of graft failure owing to persistent ALRL. The concept of combining a lateral extra-articular procedure to augment ACLR for the treatment of ACL injury emerged with a view to decrease the failure rate of either procedure in isolation. This state-of-the-art review discusses the history of the anatomy of the ALC, the biomechanics of a variety of lateral extra-articular augmentation procedures, and provides clinical guidelines for their use in primary ACLR.

Effect of Radiological Evidence of Kaplan Fiber Injury on the Clinical and Functional Outcomes After Acute Anterior Cruciate Ligament Reconstruction

BACKGROUND

A paucity of information is available regarding the clinical outcomes of patients with radiological evidence of Kaplan fiber (KF) injury who undergo anterior cruciate ligament (ACL) reconstruction (ACLR).

PURPOSE/HYPOTHESIS

The purpose was to compare clinical and functional outcomes in patients undergoing acute primary ACLR with and without magnetic resonance imaging (MRI) evidence of KF injury. The hypothesis was that there would be no difference in clinical or functional outcomes in patients with versus those without radiological evidence of KF injury.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

MRI analysis was conducted on patients in a longitudinal prospective study of ACL injury. Only patients who had an MRI scan and had undergone isolated primary ACLR within 60 days of injury were included. MRI was performed using standard knee protocols, and diagnostic criteria were applied to identify KF injury. A total of 32 patients with KF injury (mean age, 24.2 years; 21 male, 11 female) were identified and matched for sex, age, graft type, and preinjury activity with 90 patients who had intact KF. Patients were followed up at 12 months with KT-1000 arthrometer measurements of side-to-side difference in anterior knee laxity, single- and triple-hop limb symmetry index (LSI), Marx activity and International Knee Documentation Committee (IKDC) scores, and return to sport (RTS) rates at 12 months and 24 months.

RESULTS

No differences were found in anterior knee laxity and single- and triple-hop LSI values between the KF-intact and KF-injured cohorts at 12 months. No differences in Marx and IKDC scores were found between the groups at 12 months and 2 years. The overall rate of RTS within 24 months was 75% (92/122), and 5 patients (2 KF-injured; 3 KF-intact) had a subsequent graft rupture.

CONCLUSION

We found no difference in clinical or functional outcomes in patients with and without radiological evidence of KF injury who underwent acute primary ACLR. Based on these findings, the radiological presence of KF injury at the time of acute ACL injury should not be regarded as a risk factor for a negative prognosis after ACLR.

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

BACKGROUND

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

PURPOSE

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

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

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

RESULTS

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

CONCLUSION

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

Will the Kaplan Fiber Complex Be the ‘‘New Anterolateral Ligament’’? Insights from Direct Surgical Exploration in the Context of ACL Injury and Reconstruction

According to the most popular scientific literature database in 2022, nearly 20 papers mentioning the “Kaplan Fiber” complex have been published in the last 2 years, highlighting the role of this anatomical structure in the context of anterior cruciate ligament tear [...]

Modified iliotibial band tenodesis versus lateral extracapsular tenodesis, to augment anterior cruciate ligament reconstruction: a 2-year randomized controlled trial

BACKGROUND

Residual instability following anterior cruciate ligament (ACL) reconstruction is associated with disruption of the anterolateral complex (ALC). Our goal was to conduct a randomized controlled trial comparing the effectiveness of modified Iliotibial tenodesis (MITBT) versus lateral extracapsular tenodesis (LET) to correct this residual instability.

METHODS

Group 1 underwent MITBT, Group 2 LET, added to the ACL reconstruction. Outcomes of interest were Tegner activity Scores (TAS), international knee documentation committee score (IKDC), knee osteoarthritis outcome score (KOOS), ACL related quality of life (ACL QoL), recurrent ACL rupture and meniscal tears. Follow-up was 2 years. Statistical analysis used chi-squared tests, frequency statistics and generalized linear models. We have followed the guidelines outlined in the CONSORT statement.

RESULTS

A total of 164 patients were randomized, 84 to Group 1, 80 to Group 2. Group 1 had higher TAS than Group 2, at 2 years (median 8, range 7-10 vs. median 7, range 5-9, P<0.001). Group 1 had higher ACL QoL scores at 1 and 2 years post-surgery (82.1, SD2.7 vs. 67.9, SD 4.0, P< 0.001 and 82.5, SD 2.6 vs. 68.8, SD 3.8, P<0.001, respectively), and higher KOOS Sport/recreation subscale at both 1 and 2 years (91.5, SD4.3 vs. 78.3, SD7.9, P<0.001 and 91.8, SD4.8 vs. 80.4, SD 9.5, P<0.001). Risk of recurrent ACL rupture (0% vs. 5%, P = 0.040-0.05) and medial meniscal tear (2.4% vs. 14%, P = 0.007-0.02) were lower in Group 1.

CONCLUSION

Augmentation of ACL reconstruction with the MITBT, rather than the LET, was associated with improved outcomes, and lower risks of recurrent ACL rupture and medial meniscal tears.