High Rate of Initially Overlooked Kaplan Fiber Complex Injuries in Patients With Isolated Anterior Cruciate Ligament Injury

Utility of three-dimensional proton density-weighted sequence MRI in knee for the assessment of Anterolateral complex in Anterior cruciate ligament injury

OBJECTIVES

To assess the proportion and pattern of injury of the anterolateral ligament (ALL) and the Kaplan fibre (KF) complex in knees with anterior cruciate ligament (ACL) injuries on MRI using three-dimensional (3D) proton density (PD) sequences.

METHODS

A total of 88 patients having ACL injury were included in this cross-sectional study. 3D PD sequences were used to assess injury of ALL and the KF complex and were graded on a scale of 0 to 3. MR images were evaluated by two radiologists. Interobserver agreement was determined using Cohen Kappa.

RESULTS

Femoral, meniscal, and tibial portions of ALL were visualized in 90.9%, 92%, and 94.3% of the study subjects, respectively. Proximal and distal KF were visualized in 92% and 93.2% of patients, respectively. Injury to ALL and KF was seen in 63.6% and 17% of the patients, respectively. Excellent interobserver agreement was noted for the identification and grading of ALL and KF complex injuries.

CONCLUSIONS

Oblique reformatted 3DPD MRI reliably detect ALC; however, ALL injury is better characterized than KF injury using this sequence.

ADVANCES IN KNOWLEDGE

Given the potential role of anterolateral complex (ALC) in maintaining the rotational stability of the knee, ALC assessment using the 3D PD sequences and their oblique reformatted images should be incorporated as routine review area of the knee MRI, particularly in the setting of ACL tear.

Role of the Anterior Cruciate Ligament, Anterolateral Complex, and Lateral Meniscus Posterior Root in Anterolateral Rotatory Knee Instability: A Biomechanical Study

BACKGROUND

Injuries to the anterior cruciate ligament (ACL), Kaplan fibers (KFs), anterolateral capsule/ligament (C/ALL), and lateral meniscus posterior root (LMPR) have been separately linked to anterolateral instability.

PURPOSE

To investigate the contributions of the ACL, KFs, C/ALL, and LMPR to knee stability and to measure instabilities resulting from their injury.

STUDY DESIGN

Controlled laboratory study.

METHODS

Ten fresh-frozen human knees were tested robotically to determine restraints of knee laxity at 0° to 90° of flexion. An 88-N anterior-posterior force (anterior and posterior tibial translation), 5-N·m internal-external rotation, and 8-N·m valgus-varus torque were imposed and intact kinematics recorded. The kinematics were replayed after sequentially cutting the structures (order varied) to calculate their contributions to stability. Another 10 knees were tested in a kinematics rig with optical tracking to measure instabilities after sequentially cutting the structures across 0° to 100° of flexion. One- and 2-way repeated-measures analyses of variance with Bonferroni correction were used to find significance (P < .05) for the robotic and kinematics tests.

RESULTS

The ACL was the primary restraint for anterior tibial translation; other structures were insignificant (<10% contribution). The KFs and C/ALL resisted internal rotation, reaching 44% ± 23% (mean ± SD; P < .01) and 14% ± 13% (P < .05) at 90°. The LMPR resisted valgus but not internal rotation. Anterior tibial translation increased after ACL transection (P < .001) and after cutting the lateral structures from 70° to 100° (P < .05). Pivot-shift loading increased anterolateral rotational instability after ACL transection from 0° to 40° (P < .05) and further after cutting the lateral structures from 0° to 100° (P < .01).

CONCLUSION

The anterolateral complex acts as a functional unit to provide rotatory stability. The ACL is the primary stabilizer for anterior tibial translation. The KFs are the most important internal rotation restraint >30° of flexion. Combined KFs + C/ALL injury substantially increased anterolateral rotational instability while isolated injury of either did not. LMPR deficiency did not cause significant instability with the ACL intact.

CLINICAL RELEVANCE

This study is a comprehensive biomechanical sectioning investigation of the knee stability contributions of the ACL, anterolateral complex, and LMPR and the instability after their transection. The ACL is significant in controlling internal rotation only in extension. In flexion, the KFs are dominant, synergistic with the C/ALL. LMPR tear has an insignificant effect with the ACL intact.

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.

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.

Investigation of the medium-term effect of osteoprotegerin/bone morphogenetic protein 2 combining with collagen sponges on tendon-bone healing in a rabbit

BACKGROUND

Osteoprotegerin (OPG) and bone morphogenetic protein-2 (BMP-2) could be administered sequentially to promote tendon-bone healing. There remain several unresolved issues in our previously published study: a) the release kinetics of OPG/BMP-2 from the OPG/BMP-2/collagen sponge (CS) combination in vitro remained unclear; b) the medium-term effect of the OPG/BMP-2/CS combination was not analyzed. Hence, we design this study to address the issues mentioned above.

METHODS

30 rabbits undergoing anterior cruciate ligament reconstruction (ACLR) with an Achilles tendon autograft randomly received one of the 3 delivery at the femoral and tibial tunnels: OPG/BMP-2, OPG/BMP-2/CS combination, and nothing (blank control). At 8 and 24 weeks post-surgery, the biomechanical tests and histologic analysis were used to evaluate the tendon-bone healing.

RESULTS

In mechanical tests, the OPG/BMP-2/CS group showed a higher final failure load and stiffness than the other groups at 8 and 24 weeks. Additionally, the maximum stretching distance showed a decreasing trend. The mechanical failure pattern of samples shifted from a tunnel pull-away to a graft midsubstance rupture after OPG/BMP-2/CS-treated. From histological analysis, the OPG/BMP-2/CS treatment increased the amount of collagen fibers (collagen I and II) and promoted fibrocartilage attachment.

CONCLUSION

CS as a carrier promotes the medium-term effect of OPG and BMP-2 on tendon-bone healing at the tendon-bone interface in a rabbit ACLR model. OPG, BMP-2 and CS were already applied in several clinical practice, but a further study of clinic use of OPG/BMP-2/CS is still needed.

The Association Between Bone Bruises and Concomitant Ligaments Injuries in Anterior Cruciate Ligament Injuries: A Systematic Review and Meta-analysis

Background

Bone bruises and concomitant ligament injuries after anterior cruciate ligament (ACL) injuries have attracted attention, but their correlation and potential clinical significance remain unclear.

Purpose

To assess the relationship between bone bruises and concomitant ligamentous injuries in ACL injuries.

Study design

Systematic review.

Methods

A comprehensive search of PubMed, Embase, Web of Science, and Cochrane Library was completed from inception to October 20, 2021. All articles that evaluated the relationship between bone bruises and related ligaments injuries were included. Methodological Index for Non-Randomized Studies (MINORS) was used for quality assessment as well as Review Manager 5.3 was used for data analysis.

Results

A total of 19 studies evaluating 3292 patients were included. After meta-analysis, anterolateral ligament (ALL) injuries were associated with bone bruising on the lateral tibial plateau (LTP) (RR = 2.33; 95% CI 1.44-3.77; p = 0.0006), lateral femoral condyle (LFC) (RR = 1.97; 95% CI 1.37-2.85; p = 0.0003) and medial tibial plateau (MTP) (RR = 1.62; 95% CI 1.24-2.11; p = 0.0004); Moreover, medial collateral ligament (MCL) injuries were associated with bone bruising on the femur (RR = 1.49; 95% CI 1.17-1.90; p = 0.001), and no statistical significance was found between bone bruising on the MTP and Kaplan fiber (KF) injuries (RR = 1.58; 95% CI 1.00-2.49; p = 0.05). Nonetheless, the current evidence did not conclude that bone bruises were associated with lateral collateral ligament (LCL) injuries.

Conclusion

For individuals with an ACL injury, bone bruises of the LTP, LFC, and MTP can assist in the diagnosis of ALL injuries. Furthermore, femoral bruising has potential diagnostic value for MCL injuries. Knowing these associations allows surgeons to be alert to ACL-related ligament injuries on MRI and during operations in future clinical practice.

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.

Variation in Kaplan fiber insertion to the distal femur and surgical implications: A cadaveric anatomical study comparing Asian and Caucasian knees

BACKGROUND

The iliotibial band together with its attachment to the distal femur, known eponymously as the Kaplan fibers, has been shown to contribute to anterolateral rotatory stability of the knee. However, there remains paucity of data regarding the detailed anatomy of the Kaplan fibers to aid us in anatomical-based surgical reconstruction of these structures. The aim of our study was to identify and compare the presence and quantitative anatomy of the Kaplan fibers in Caucasian and Asian cadavers.

METHODS

Twenty paired fresh-frozen Asian and 20 unpaired embalmed Caucasian cadaveric knees were dissected using a standard outside-in technique. The presence, qualitative and quantitative measurements of any distal femoral attachments of the iliotibial band were recorded. Mean values of its dimensions were calculated and compared between the Caucasian and Asian groups.

RESULTS

A consistent supracondylar attachment of the iliotibial band was found in all Caucasian knees and in 19 of 20 Asian knees. The fibers were noted to have two variations with regard to their insertion to the distal femur, either as a single limb or as a double limb attachment, averaging between 30 mm and 40 mm from the lateral femoral epicondyle. No statistically significant difference was noted in dimensions of the fibers between the Caucasian and Asian groups.

CONCLUSIONS

The Kaplan fibers are a consistent attachment of the iliotibial band at the distal femur in both Caucasian and Asian knees with two different patterns of insertion. Surgical reconstructions should aim to recreate these attachments to be as anatomically based as possible.

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.

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 [...]

Effect of Nursing in Operating Room Combined with Intraoperative Heat Preservation Intervention on Prevention of Incision Infection and Improvement of Hemodynamics in Patients with Anterior Cruciate Ligament Injury and Reconstruction under Knee Arthroscopy

Objective

To explore the effect of nursing in operating room combined with intraoperative heat preservation intervention on preventing incision infection and improving hemodynamics in patients with anterior cruciate ligament (ACL) injury and reconstruction under knee arthroscopy.

Methods

About 200 patients with knee arthroscopic ACL reconstruction in our hospital from January 2019 to July 2021 were enrolled. The patients were randomly assigned into two groups: the control group and the study group. The former group received nursing care in the operating room operating room and the latter group received nursing care in operating room combined with intraoperative heat preservation intervention. Nursing satisfaction, incidence of incision infection, knee joint VAS score, knee joint range of motion, knee joint Lysholm score, and hemodynamic indexes were compared.

Results

First of all, we compared the nursing satisfaction, the study group was very satisfied in 78 cases, satisfactory in 20 cases, and general in 2 cases, and the satisfaction rate was 100.00%, while in the control group, 445 cases were very satisfied, 20 cases were satisfied, 15 cases were general, and 8 cases were dissatisfied. The satisfaction rate was 82.00%. The nursing satisfaction of the study group was higher compared to the control group (P < 0.05). Secondly, we compared the incidence of incision infection. The incidence of incision infection in the study group was lower compared to the control group (P < 0.05). With regard to the knee joint VAS score, the knee joint VAS score of the study group was lower compared to the control group at 2 weeks, 4 weeks, 8 weeks, and 12 weeks after operation (P < 0.05). In terms of the range of motion of the knee joint, the range of motion of the knee joint in the study group was higher compared to the control group at 2 weeks, 4 weeks, 8 weeks, and 12 weeks after operation (P < 0.05). Regarding the knee joint Lysholm score, the knee joint Lysholm score of the study group was higher compared to the control group at 2 weeks, 4 weeks, 8 weeks, and 12 weeks after operation (P < 0.05). Finally, we compared the hemodynamic indexes. Before nursing, there exhibited no significant difference (P > 0.05). During and after nursing, the indexes of HR and MAP in the study group fluctuated little (P < 0.05).

Conclusion

During the perioperative period of patients with ACL injury and reconstruction under knee arthroscopy, standardized and necessary operating room combined with intraoperative thermal insulation intervention measures should be given, attention should be paid to the management of operating room, and intraoperative thermal insulation intervention should be strengthened. It includes preoperative visit, psychological nursing of patients, strict application of antibiotics before operation, monitoring of air quality in operating room, disinfection and sterilization of surgical instruments, shortening operation time, maintaining body temperature during operation, and paying attention to hand hygiene of medical staff. It plays a supervisory role in promoting the attention of medical staff to the prevention of wound infection, which is beneficial to the healing of surgical wounds of patients. It plays a positive role in enhancing hemodynamic indexes. Comprehensive nursing intervention on the risk factors of each link can effectively prevent postoperative wound infection and strengthen the prognosis and quality of life of patients.