The concomitant lateral meniscus injury increased the pivot shift in the anterior cruciate ligament-injured knee

Lateral meniscus root tear in anterior cruciate ligament injured patients is not associated with increased rotatory knee laxity: A quantitative pivot shift analysis

OBJECTIVES

Biomechanical investigations conducted in vitro have elucidated the detrimental impact of lateral meniscus posterior root (LMPR) tears on knee contact pressures in the anterior cruciate ligament (ACL)-injured knee. Nevertheless, the influence of LMPR tears on the kinematics of ACL-injured patients remains ambiguous. The purpose of this study was to assess the impact of LMPR tears on anteroposterior and rotatory knee laxity employing a clinically validated quantitative pivot shift (QPS) analysis system.

METHODS

Patients with ACL injury recruited in a prospective ACL registry spanning from 2012 to 2020 were retrospectively screened for eligibility. Criteria for inclusion encompassed complete primary ACL tears, absence of concurrent ligamentous or osseous injuries requiring operative treatment, and no prior knee surgeries. Patients were assigned to two cohorts based on the presence (LMPR+) or absence (LMPR-) of an LMPR tear concomitant with ACL injury. Each patient underwent a standardized PS test, measurement of anterior tibial translation (ATT) (mm) using the Rolimeter, and QPS (mm) with a tablet-based image analysis system (PIVOT App). Comparative analyses of categorical variables were performed using the Fisher exact and Chi-square tests, while non-normally distributed continuous variables were compared between groups with the Mann-Whitney U test. Alfa was set at 0.05.

RESULTS

A total of 99 patients were included in the study, of which 22 were assigned to the LMPR+ and 77 to the LMPR- group. Tear depth was considered partial in 13 (59%) patients and full in 9 (41%) patients. The prevalence of medial meniscus tears was greater in the LMPR+ (n ​= ​16, 73%) compared with the LMPR- (n ​= ​33, 43%) group (p ​= ​0.01). No difference was observed in ATT measured with the Rolimeter (p ​= ​0.63). Similarly, no difference was found in QPS between the LMPR+ (2.3 ​mm) and the LMPR- (1.9 ​mm) group (p ​= ​0.08).

CONCLUSION

Utilizing QPS in this investigation, LMPR tears do not significantly increase ATT or rotatory knee laxity. Consequently, although repairing LMRT associated with ACL injuries may be advisable for minimizing joint stress, their impact on controlling the PS in patients remains uncertain.

LEVEL OF EVIDENCE

III, retrospective comparative study.

Secondary restraints in ACL reconstruction: State-of-the-art

At-risk patients continue to experience a high likelihood of graft rupture after anterior cruciate ligament (ACL) reconstruction (ACLR). This narrative review seeks to provide the reader with an evidence-based synopsis of state-of-the-art concepts related to secondary restraint lesions, and how addressing them surgically might result in improved outcomes of ACLR.

Management of Meniscus Pathology with Concomitant Anterior Cruciate Ligament Injury

PURPOSE OF REVIEW

The purpose of this review is to summarize current clinical knowledge on the prevalence and types of meniscus pathology seen with concomitant anterior cruciate ligament (ACL) injury, as well as surgical techniques, clinical outcomes, and rehabilitation following operative management of these pathologies.

RECENT FINDINGS

Meniscus pathology with concomitant ACL injury is relatively common, with reports of meniscus pathology identified in 21-64% of operative ACL injuries. These concomitant injuries have been associated with increased age and body mass index. Lateral meniscus pathology is more common in acute ACL injury, while medial meniscus pathology is more typical in chronic ACL deficiency. Meniscus tear patterns associated with concomitant ACL injury include meniscus root tears, lateral meniscus oblique radial tears of the posterior horn (14%), and ramp lesions of the medial meniscus (8-24%). These meniscal pathologies with concomitant ACL injury are associated with increased rotational laxity and meniscal extrusion. There is a paucity of comparative studies to determine the optimal meniscus repair technique, as well as rehabilitation protocol, depending on specific tear pattern, location, and ACL reconstruction technique. There has been a substantial increase in recent publications demonstrating the importance of meniscus repair at the time of ACL repair or reconstruction to restore knee biomechanics and reduce the risk of progressive osteoarthritic degeneration. Through these studies, there has been a growing understanding of the meniscus tear patterns commonly identified or nearly missed during ACL reconstruction. Surgical management of meniscal pathology with concomitant ACL injury implements the same principles as utilized in the setting of isolated meniscus repair alone: anatomic reduction, biologic preparation and augmentation, and circumferential compression. Advances in repair techniques have demonstrated promising clinical outcomes, and the ability to restore and preserve the meniscus in pathologies previously deemed irreparable. Further research to determine the optimal surgical technique for specific tear patterns, as well as rehabilitation protocols for meniscus pathology with concomitant ACL injury, is warranted.

Double-bundle ACL combined with ALL reconstruction for patients at high risk of ACL failure: clinical and radiological results

BACKGROUND

We investigated whether double-bundle (DB) anterior cruciate ligament (ACL) reconstruction (ACLR) combined with anterolateral ligament reconstruction (ALLR) improved clinical and radiological outcomes in patients at high risk of ACL failure. The primary outcome was graft failure, and secondary outcomes included knee stability and patient-reported outcome measures (PROMs).

PATIENTS AND METHODS

Fifty-two patients who underwent DB ACLR combined with ALLR were included in this retrospective cohort study. Preoperative risk factors, including femorotibial angle (FTA), lateral tibial slope (LTS), medial tibial slope (MTS), and meniscal tears, were assessed using X-ray and magnetic resonance imaging (MRI). The grade of post-operative pivot shift, Lysholm score, and Tegner activity score were used to assess clinical outcomes. The minimum follow up duration was 2 years.

RESULTS

The cohort (mean age, 26.1 ± 9.4 years; 51.9% male) had a mean follow-up duration of 28.9 ± 3.4 months. Preoperatively, 57.8% had lateral meniscus (LM) tears, and 61.0% had a grade 2-3 pivot shift. Postoperatively, no graft failures or revision cases occurred during follow-up. Approximately 90.4% of the patients exhibited a negative pivot shift (p < 0.001), with Lysholm and Tegner activity scores of 92.5 ± 6.1 and 5.1 ± 2.0. The medial meniscus (MM) tear group had a significantly smaller FTA than the intact group (p = 0.043). No significant differences in PROMs were found between the LM tear and intact LM groups or between the high and low MTS or LTS groups (p = n.s.).

CONCLUSION

DB ACLR combined with ALLR had satisfactory clinical outcomes in patients at high risk of ACL failure, with no graft failures observed during a mean follow-up duration of 2.4 years. The technique effectively reduced the postoperative pivot shift, regardless of preoperative risk factors.

STUDY DESIGN

Level IV, retrospective therapeutic case-series.

TRAIL REGISTRATION

ethical approval number, 202300134B0; ethical committee, the Institutional Review Board of Chang Gung Medical Foundation.

Subjective grade of apprehension during the pivot-shift test reflects patient-reported outcomes more than conventional pivot-shift test grade after ACL reconstruction

PURPOSE

To investigate whether the pivot-shift test reflects patient-reported outcomes 1 year after anterior cruciate ligament (ACL) reconstruction based on a multicentre prospective cohort study.

METHODS

This study included patients who underwent primary ACL reconstruction using the hamstring tendons. The pivot-shift test grades were determined according to the International Knee Documentation Committee (IKDC) form as 0, 1+, 2+ or 3+. In addition, patients' subjective apprehension during the pivot-shift test were classified as 0 (no-apprehension), 1+ (mild-apprehension), 2+ (moderate-apprehension) or 3+ (severe-apprehension). In this study, a positive pivot-shift test was defined as grade 1+ or higher.

RESULTS

A total of 837 patients were enroled in this study. One year postoperatively, there was no significant difference in the Knee injury and Osteoarthritis Outcome Score (KOOS), IKDC score, Lysholm knee scale and Tegner activity scale between the positive (118 patients) and negative (719 patients) groups of the conventional IKDC grading of the pivot-shift test. However, when divided into two groups based on the apprehension grading of the pivot-shift test after surgery, the postoperative scores were significantly lower in the apprehension-positive group (114 patients) than those in the apprehension-negative group (723 patients) on the Tegner activity scale and KOOS Symptom, Sports/Rec and Quality of Life subscales.

CONCLUSIONS

Patients' subjective apprehension during the pivot-shift test after ACL reconstruction was significantly associated with the postoperative Tegner activity scale and three subscales of the KOOS. However, there was no association between the conventional IKDC grading of the pivot-shift test and any patient-reported outcomes postoperatively.

LEVEL OF EVIDENCE

Level II.

Association Between MRI Signal Intensity of the Repaired Lateral Meniscus and Residual Anterolateral Knee Laxity After ACL Reconstruction

Background

Anterolateral knee laxity (ALLx) has been linked to tears of the lateral meniscus (LM) and anterior cruciate ligament (ACL) injury.

Purpose

To investigate the longitudinal relationship between the signal intensity (SI) of the repaired LM on magnetic resonance imaging (MRI) and residual ALLx after ACL reconstruction (ACLR).

Study Design

Cohort study; Level of evidence, 3.

Methods

Included were 87 patients who underwent double-bundle ACLR and lateral meniscal repair (mean age, 23.5 years; body mass index, 23.7 kg/m2; 56 women) at a single institution between 2010 and 2019. Proton density-weighted (PDW) and T2-weighted (T2W) MRI was performed at 3, 6, and 12 months postoperatively, and the SI ratio (SIR) was calculated as (SI of the repaired LM)/(SI of the posterior cruciate ligament). At the 12-month follow-up, ALLx was evaluated using the pivot-shift test; an International Knee Documentation Committee grade ≥1 indicated residual ALLx.

Results

Overall, 12 patients (13.8%) exhibited ALLx at 12 months postoperatively. At 3 months postoperatively, the SIR on PDW images (SIR-PDW) was significantly higher in patients with ALLx versus those without ALLx (1.98 ± 0.77 vs 1.49 ± 0.52, respectively; P = .007); there was no difference in the SIR on T2W images between the groups. SIR-PDW at 3 months postoperatively was correlated negatively with patient age (r = -0.308, P = .004). When patients were stratified into a younger (≤22 years; n = 53; ALLx = 7 [13.2%]) and an older (>22 years; n = 34; ALLx = 5 [14.7%]) group, the area under the receiver operating characteristic curves (AUCs) for SIR-PDW in the younger group were statistically significant for predicting the prevalence of ALLx at all follow-up times (AUCs, 0.733-0.788) with optimal cutoff values of 2.00 at 3 months, 1.50 at 6 months, and 1.50 at 12 months. Logistic regression analysis revealed that if younger patients consistently had higher SIR-PDW values than the cutoff values, they were more likely to have residual ALLx (odds ratios, 10.24-23.57).

Conclusion

For younger patients who underwent both ACLR and lateral meniscal repair, higher MRI SI of the repaired LM was associated with a higher prevalence of residual ALLx.

Noninvasive and Reliable Quantification of Anteromedial Rotatory Knee Laxity: A Pilot Study on Healthy Individuals

BACKGROUND

Anteromedial rotatory instability (AMRI) of the knee is a complex and severe condition caused by injury to the anterior cruciate ligament and/or the medial collateral ligament. Clinical studies dealing with AMRI are rare, and objective measurements are nonexistent.

PURPOSE/HYPOTHESIS

The objectives of this study were, first, to quantify anteromedial rotatory knee laxity in healthy individuals using a noninvasive image analysis software and, second, to assess intra- and interrater reliability and equivalence in measuring anteromedial knee translation (AMT). It was hypothesized that AMT could be reliably quantified using a noninvasive image analysis software.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This prospective proof-of-concept study included healthy individuals aged 16 to 40 years with no history of knee injury or surgery. Three adhesive surface markers were placed on predefined landmarks on the medial side of the knee. Three independent investigators examined anteromedial rotatory knee laxity with an anterior drawer test in different tibial rotations (neutral tibial rotation, 15° of external tibial rotation, and 15° of internal tibial rotation). The entire examination of each knee was recorded, and AMT including the side-to-side difference (SSD) was assessed using a freely available and validated image analysis software (PIVOT iPad application). Group comparisons were performed using a 1-way analysis of variance with Bonferroni-adjusted post hoc analysis. Intraclass correlation coefficients (ICCs) were calculated to assess inter- and intrarater reliability of AMT measurements. Equivalence of measurements was evaluated using the 2 one-sided t-test procedure.

RESULTS

Anteromedial rotatory knee laxity was assessed in 30 knees of 15 participants (53% male) with a mean age of 26.2 ± 3.5 years. In all 3 raters, the highest AMT was observed in neutral tibial rotation (range of means, 2.2-3.0 mm), followed by external tibial rotation (range of means, 2.0-2.4 mm) and internal tibial rotation (range of means, 1.8-2.2 mm; P < .05). Intrarater reliability of AMT (ICC, 0.88-0.96) and SSD (ICC, 0.61-0.96) measurements was good to excellent and moderate to excellent, respectively. However, interrater reliability was poor to moderate for AMT (ICC, 0.44-0.73) and SSD (ICC, 0.12-0.69) measurements. Statistically significant equivalence of AMT and SSD measurements was observed between and within raters for almost all testing conditions.

CONCLUSION

Anteromedial rotatory knee laxity could be quantified using a noninvasive image analysis software, with the highest AMT observed during neutral tibial rotation in uninjured individuals. Reliability and equivalence of measurements were good to excellent within raters and moderate between raters.

Concomitant Lateral Meniscus Tear is Associated with Residual Rotatory Knee Instability 1 Year after Anterior Cruciate Ligament Reconstruction: Case-cohort Study

Lateral meniscus tear (LMT) accompanied by anterior cruciate ligament (ACL) injuries has been reported to provoke rotatory instability of the affected knee joint. Unfortunately, these previous papers did not determine whether LMT-derived rotatory knee instability is residual because only preoperative or time zero data exists. This study aimed to longitudinally investigate how the prevalence of comorbid LMT is associated with residual rotatory knee instability (RKI) 1 year after ACL reconstruction (ACLR). A total of 327 patients who underwent double-bundle ACLR (average age: 23.4 years, body mass index: 23.5 kg/m2, 215 females). The patients were divided into three groups based on arthroscopy: 1) intact lateral meniscus (LM); 2) unrepaired LMT; 3) repaired LMT. At the 1-year follow-up, the pivot-shift test was performed. The prevalence of RKI, determined according to IKDC grades (grade ≥1 denoted RKI), was compared with chi-square or Fisher's exact tests. Thirty-eight patients (11.6%) had RKI; 203 subjects (62.1%) showed LMT, and 124 patients were diagnosed with an intact LM. Out of the 203 patients, 79 (38.9%) underwent LM repair. RKI was more prevalent in the LMT group than in the intact group (13.8% versus 8.1%, p = 0.117; Odds ratio: 1.499 [95%CI: 0.864 - 2.600]). In addition, the prevalence of RKI was significantly higher in the LM-repair group than in the intact-LM group (17.7% versus 8.1%, p = 0.038; Odds Ratio: 2.455 [95%CI: 1.032 - 5.842]). Medial meniscus tear (MMT) was detected in 113 patients (34.6%); RKI prevalence was not statistically different between the intact-MM group and the MMT group (12.2% versus 10.6%, p = 0.681). The current cohort study clarified that LMT comorbid with ACL injury was longitudinally associated with increased RKI prevalence 1 year after ACLR. Therefore, patients who underwent both ACLR and LM repair demonstrated a significantly higher prevalence of residual RKI.

The "Bankart knee": high-grade impression fractures of the posterolateral tibial plateau lead to increased translational and anterolateral rotational instability of the ACL-deficient knee

PURPOSE

The aim of this biomechanical cadaver study was to evaluate the effects of high-grade posterolateral tibia plateau fractures on the kinematics of anterior cruciate ligament (ACL)-deficient joints; it was hypothesized that, owing to the loss of the integrity of the osseous support of the posterior horn of the lateral meniscus (PHLM), these fractures would influence the biomechanical function of the lateral meniscus (LM) and consequently lead to an increase in anterior translational and anterolateral rotational (ALR) instability.

METHODS

Eight fresh-frozen cadaveric knees were tested using a six-degree-of-freedom robotic setup (KR 125, KUKA Robotics, Germany) with an attached optical tracking system (Optotrack Certus Motion Capture, Northern Digital, Canada). After the passive path from 0 to 90° was established, a simulated Lachman test and pivot-shift test as well as external rotation (ER) and internal rotation (IR) were applied at 0°, 30°, 60° and 90° of flexion under constant 200 N axial loading. All of the parameters were initially tested in the intact and ACL-deficient states, followed by two different types of posterolateral impression fractures. The dislocation height was 10 mm, and the width was 15 mm in both groups. The intraarticular depth of the fracture corresponded to half of the width of the posterior horn of the lateral meniscus in the first group (Bankart 1) and 100% of the meniscus width in the second group (Bankart 2).

RESULTS

There was a significant decrease in knee stability after both types of posterolateral tibial plateau fractures in the ACL-deficient specimens, with increased anterior translation in the simulated Lachman test at 0° and 30° of knee flexion (p = 0.012). The same effect was seen with regard to the simulated pivot-shift test and IR of the tibia (p = 0.0002). In the ER and posterior drawer tests, ACL deficiency and concomitant fractures did not influence knee kinematics (n.s.).

CONCLUSION

This study demonstrates that high-grade impression fractures of the posterolateral aspect of the tibial plateau increase the instability of ACL-deficient knees and result in an increase in translational and anterolateral rotational instability.

What it takes to have a high-grade pivot shift-focus on bony morphology

PURPOSE

Variations in femoral and tibial bony morphology have been associated with higher clinical grading and increased quantitative tibial translation, but not tibial acceleration, during the pivot shift test following anterior cruciate ligament (ACL) injury. The purpose of this study was to determine the impact of femoral and tibial bony morphology, including a measurement influenced by both parameters (the Lateral Tibiofemoral Articular Distance (LTAD)), on the degree of quantitative tibial acceleration during the pivot shift test and rates of future ACL injury.

METHODS

All patients who underwent primary ACL reconstruction from 2014 to 2019 by a senior orthopedic surgeon with available quantitative tibial acceleration data were retrospectively reviewed. All patients underwent a pivot shift examination under anesthesia with a triaxial accelerometer. Measurements of femoral and tibial bony morphology were performed by two fellowship-trained orthopedic surgeons using preoperative magnetic resonance imaging and lateral radiographs.

RESULTS

Fifty-one patients were included at a mean follow-up of 4.4 years. The mean quantitative tibial acceleration during the pivot shift was 13.8 m/s2 (range: 4.9-52.0 m/s2). A larger Posterior Condylar Offset Ratio (r = 0.30, p = 0.045), smaller medial-to-lateral width of the medial tibial plateau (r = - 0.29, p = 0.041), lateral tibial plateau (r = - 0.28, p = 0.042), and lateral femoral condyle (r = - 0.29, p = 0.037), and a decreased LTAD (r = - 0.53, p < 0.001) significantly correlated with increased tibial acceleration during the pivot shift. Linear regression analysis demonstrated an increase in tibial acceleration of 1.24 m/s2 for every 1 mm decrease in LTAD. Nine patients (17.6%) sustained ipsilateral graft rupture and 10 patients (19.6%) sustained contralateral ACL rupture. No morphologic measurements were associated with rates of future ACL injury.

CONCLUSION

Increased convexity and smaller bony morphology of the lateral femur and tibia were significantly associated with increased tibial acceleration during the pivot shift. Additionally, a measurement, termed the LTAD, was found to have the strongest association with increased tibial acceleration. Based on the results of this study, surgeons can utilize these measurements to preoperatively identify patients at risk of increased rotatory knee instability.

LEVEL OF EVIDENCE

Level IV.

Differences in postoperative knee function based on concomitant treatment of lateral meniscal injury in the setting of primary ACL reconstruction

BACKGROUND

Concomitant lateral meniscal (LM) injuries are common in acute anterior cruciate ligament (ACL) ruptures. However, the effect of addressing these injuries with various treatment methods during primary ACL reconstruction (ACLR) on patient-reported outcomes (PROs) is unknown. Therefore, the purpose of this study was to compare postoperative Knee injury and Osteoarthritis Outcome Score (KOOS) at 2-, 5-, and 10-years after isolated primary ACLR to primary ACLR with various treatment methods to address concomitant LM injury.

METHODS

This study was based on data from the Swedish National Knee Ligament Registry. Patients ≥ 15 years with data on postoperative KOOS who underwent primary ACLR between the years 2005 and 2018 were included in this study. The study population was divided into five groups: 1) Isolated ACLR, 2) ACLR + LM repair, 3) ACLR + LM resection, 4) ACLR + LM injury left in situ, and 5) ACLR + LM repair + LM resection. Patients with concomitant medial meniscal or other surgically treated ligament injuries were excluded.

RESULTS

Of 31,819 included patients, 24% had LM injury. After post hoc comparisons, significantly lower scores were found for the KOOS Symptoms subscale in ACLR + LM repair group compared to isolated ACLR (76.0 vs 78.3, p = 0.0097) and ACLR + LM injury left in situ groups (76.0 vs 78.3, p = 0.041) at 2-year follow-up. However, at 10-year follow-up, no differences were found between ACLR + LM repair and isolated ACLR, but ACLR + LM resection resulted in significantly lower KOOS Symptoms scores compared to isolated ACLR (80.4 vs 82.3, p = 0.041).

CONCLUSION

The results of this study suggest that LM injury during ACLR is associated with lower KOOS scores, particularly in the Symptoms subscale, at short- and long-term follow-up. However, this finding falls below minimal clinical important difference and therefore may not be clinically relevant.

LEVEL OF EVIDENCE

III.

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.

Steeper lateral posterior tibial slope and greater lateral-medial slope asymmetry correlate with greater preoperative pivot-shift in anterior cruciate ligament injury

PURPOSE

To investigate the association between posterior tibial slope (PTS) and preoperative pivot-shift phenomenon in anterior cruciate ligament (ACL)-injured knees.

METHODS

Fifty unilateral ACL-injured patients (mean age: 28.0 ± 11.4 years, 29 males) who underwent ACL reconstruction were retrospectively included. Patients with a history of injury to the ipsilateral knee joint, concomitant ligament injuries with ACL injury, and/or more than one year from injury to surgery, were excluded. Pivot-shift tests were performed preoperatively under general anaesthesia using an electromagnetic measurement system, and tibial acceleration (m/s²) during the posterior reduction of the tibia was measured. Medial and lateral PTS (°) were measured respectively using high-resolution CT images taken two weeks after surgery. Lateral-medial slope asymmetry was calculated by subtracting medial PTS from lateral PTS (lateral-medial PTS) and we evaluated the correlation between each PTS parameter (medial PTS, lateral PTS, and lateral-medial slope asymmetry) and tibial acceleration during the pivot-shift test. The level of significance was set at p < 0.05.

RESULTS

Medial PTS was 4.9 ± 2.0°, and lateral PTS was 5.2 ± 1.9°. The lateral-medial slope asymmetry was 0.3 ± 1.6° (range: -2.9 to 3.8). Tibial acceleration during the pivot-shift test in the ACL-injured knee was 1.6 ± 0.1 m/s². Preoperative tibial acceleration was positively correlated with lateral PTS (r = 0.436, p < 0.01), and lateral-medial slope asymmetry (r = 0.443, p < 0.01), while no significant correlation was found between preoperative tibial acceleration and medial PTS (r = 0.06, p = 0.70).

CONCLUSION

Preoperative greater tibial acceleration during the pivot-shift test was associated with steeper lateral PTS and greater lateral-medial slope asymmetry in ACL-injured knees. These findings improve our understanding of anterolateral rotatory knee laxity by linking tibial bony morphology to quantitative measurement of pivot-shift phenomenon. Surgeons should be aware that not only lateral PTS but also lateral-medial slope asymmetry are the factors associated with preoperative pivot-shift.

LEVEL OF EVIDENCE

Level IV.

High-grade pivot-shift phenomenon after anterior cruciate ligament injury is associated with asymmetry of lateral and medial compartment anterior tibial translation and lateral meniscus posterior horn tears

PURPOSE

To investigate whether the high-grade pivot-shift phenomenon is associated with asymmetry of the lateral and medial compartment anterior tibial translation (L-ATT and M-ATT) and lateral meniscus posterior horn (LMPH) tears in anterior cruciate ligament (ACL) injuries.

METHODS

A retrospective analysis was performed on 192 consecutive patients who had complete ACL injuries between January 2019 and December 2020. Among these, 156 met the inclusion criteria. L-ATT and M-ATT were measured using preoperative weight-bearing magnetic resonance imaging (MRI), and the differences between L-ATT and M-ATT were calculated. Thirty-five patients who demonstrated excessive differences in L-ATT and M-ATT (> 6.0 mm) were regarded as asymmetric (study group), and 36 patients with minimal or no differences in L-ATT and M-ATT (< 3.0 mm) were allocated to the control group. Demographic data, grade of the pivot-shift test, integrality of LMPH, and medial meniscus posterior horn (MMPH) were compared between the groups. Moreover, predictors of high-grade pivot-shift phenomenon, including asymmetry of L-ATT and M-ATT, integrity of LMPH and MMPH, time from injury to surgery, sex, age, and body mass index (BMI) were assessed using multivariable logistic regression analysis.

RESULTS

The difference between L-ATT and M-ATT in the study group was significantly higher than that in the control group (mean ± SD: 8.4 ± 2.1 mm vs. 1.5 ± 1.0 mm, P < 0.001). A higher proportion of patients with high-grade pivot-shift phenomenon (2 + and 3 +) and LMPH tears were identified in the study group (high-grade pivot-shift phenomenon: 25/35 vs. 13/36, P = 0.003; LMPH tears: 18/35 vs. 5/36, P = 0.001). Additionally, asymmetry of L-ATT, M-ATT (odds ratio 5.8; 95% CI 1.7-19.8; P = 0.005), and LMPH tears (odds ratio 3.8; 95% CI 1.3-11.6; P = 0.018) were found to be good predictors of the high-grade pivot-shift phenomenon after ACL injury, whereas MMPH tears, time from injury to surgery, sex, age, and BMI were not.

CONCLUSION

In patients with ACL injury, the high-grade pivot-shift phenomenon is associated with asymmetry between L-ATT and M-ATT, and LMPH tears.

LEVEL OF EVIDENCE

III.

Anterior cruciate ligament rupture and associated Segond fracture: Incidence and effect on associated ligamentous and meniscal injuries

Introduction

The Segond fracture is an avulsion fracture of the lateral tibial plateau and is widely considered to be pathognomonic of anterior cruciate ligament (ACL) rupture. In addition to ACL rupture, Segond fractures have also been noted to be associated with significant intra-articular pathology such as meniscal injuries as well as extra-articular pathology such as collateral ligament injuries. This is likely due to the fact that the presence of a Segond fracture may represent increased rotatory instability. Whilst several studies have demonstrated the association of a Segond fracture with significant intra-articular pathology, there is a paucity of literature assessing if the combination of an ACL rupture and Segond fracture gives rise to higher rates of concomitant ligamentous and meniscal injuries. The primary objective of this study is to determine if patients with ACL ruptures associated with Segond fractures have higher rates of concomitant ligamentous and meniscal injury, when compared to patients with ACL ruptures without a Segond fracture.

Methods

A retrospective review of all patients who underwent ACL reconstruction in a single institution between 2014 to 2018 was conducted. A review of the patients’ demographics, operative notes, and radiographs was performed. X-rays and MRI scans were double-read by a board-certified radiologist and Orthopaedic surgeon.

Results

A total of 414 subjects were included. The incidence of Segond fracture was 2.4%. The mean age was 24.7±7.4 (range 16 to 60) years and 26.7±7.6 (range 16 to 38) years in patients with and without Segond fractures respectively. 89.9% of patients suffered a non-contact mechanism of injury, with sports injuries being most common (79.5%). There was a significantly higher rate of isolated lateral meniscus tears in patients with Segond fractures compared to those without (50% v.s. 20.8%) based on pre-operative MRI. (p<0.05) There were no other significant differences in associated ligamentous injuries.

Conclusion

The incidence of Segond fracture associated with ACL rupture is 2.4%. There is a significantly higher risk of a concomitant isolated lateral meniscus tear in ACL ruptures associated with a Segond fracture. There is no significantly higher risk of concomitant ligamentous injuries in ACL ruptures associated with a Segond fracture.

The coronal lateral collateral ligament sign in the anterior cruciate ligament-injured knees was observed regardless of the knee laxity based on the quantitative measurements

PURPOSE

The coronal lateral collateral ligament (LCL) sign has been reported to be associated with deviated position of the tibia on MRI due to anterior cruciate ligament (ACL) injuries. However, the relationships between LCL sign and clinical knee laxity evaluations are still unclear. The purpose of the study was to investigate the relationship between the coronal LCL sign and knee laxity measurements.

METHODS

A retrospective review of unilateral ACL injured patients who underwent ACL reconstruction was performed. The coronal LCL sign was determined using magnetic resonance imaging (MRI). Clinical grading of the pivot-shift test, KT-1000 measurements, and quantitative measurements of the Lachman test and the pivot-shift test using an electromagnetic system, were compared between patients with positive and negative coronal LCL sign. A subgroup analysis of different age groups was then performed, dividing patients to adolescent (age ≤ 18 years) and adult (age > 18 years) groups.

RESULTS

A total of 85 patients were enrolled, of which 45 patients had coronal LCL signs. The coronal LCL sign was not associated with the pivot-shift test clinical grading (n.s), KT-1000 measurement (n.s), the tibial translation during the Lachman test (n.s), or with tibia acceleration (n.s) and translation (n.s) during the pivot-shift test. The subgroup analysis also showed that the aforementioned parameters were not associated with the coronal LCL sign in either adolescent or adult subgroups.

CONCLUSION

The occurrence of coronal LCL sign in MRI did not imply greater clinical knee laxity evaluations in patients with ACL tears. The knee laxity should routinely be evaluated regardless the coronal LCL sign.

LEVEL OF EVIDENCE

Level III.

Post-traumatic knee osteoarthritis; the role of inflammation and hemarthrosis on disease progression

Knee injuries such as anterior cruciate ligament ruptures and meniscal injury are common and are most frequently sustained by young and active individuals. Knee injuries will lead to post-traumatic osteoarthritis (PTOA) in 25–50% of patients. Mechanical processes where historically believed to cause cartilage breakdown in PTOA patients. But there is increasing evidence suggesting a key role for inflammation in PTOA development. Inflammation in PTOA might be aggravated by hemarthrosis which frequently occurs in injured knees. Whereas mechanical symptoms (joint instability and locking of the knee) can be successfully treated by surgery, there still is an unmet need for anti-inflammatory therapies that prevent PTOA progression. In order to develop anti-inflammatory therapies for PTOA, more knowledge about the exact pathophysiological mechanisms and exact course of post-traumatic inflammation is needed to determine possible targets and timing of future therapies.

The presence of high-grade pivot shift test preoperatively is associated with inferior functional outcomes

BACKGROUND

The effect of high-grade preoperative pivot shift test on outcomes of anterior cruciate ligament (ACL) reconstruction surgery is not very well established. The present study was conducted to study the factors associated with high-grade pivot shift test and effect of high-grade preoperative pivot shift test on functional outcomes after ACL reconstruction surgery.

METHODS

Three hundred and sixty-two patients who underwent primary ACL reconstruction surgery were enrolled in the study. The pivot shift test was performed preoperatively under anesthesia in all patients. Side of the meniscal tear, if present at the time of ACL reconstruction, was documented. Patients were divided into two groups depending upon the grade of pivot shift test: group H, high-grade pivot shift (n = 84/362; 23%); and group L, low-grade pivot shift (n = 278/362; 77%). Patients were further divided into two groups depending upon the duration of injury: acute (<6 months) and chronic (>6 months). The functional assessment was done using Lysholm score and Tegner activity scale.

RESULTS

The presence of lateral meniscus tear (27/84 vs. 53/278) or both menisci tear (29/84 vs. 60/278) was associated with high-grade pivot shift (p < 0.05). Chronic ACL tears were also observed to be associated with high-grade pivot shift (p = 0.03). The mean Lysholm score in group H and group L patients was 93.8 ± 5.1 and 95.2 ± 5.3, respectively (p = 0.04). The mean post-op Tegner activity scale in group H was 6.8 and in group L was 7.3 (p = 0.0001). Also, 181/253 (71.5%) patients returned to same or higher level of sports activity in group L as compared to 33/72 (46%) patients in group H. The incidence of graft failure in groups H and L was 6.5% (5/77) and 1.6% (4/257; p = 0.03), respectively.

CONCLUSIONS

The high-grade pivot shift is associated with chronic ACL tear (>6 months) and concomitant lateral meniscus tear. The presence of high-grade pivot shift preoperatively is associated with inferior clinical outcomes and lower rate of return to sports.

LEVEL OF EVIDENCE

Level IV, case-control study.

Kinematic Analysis of Lateral Meniscal Oblique Radial Tears in Anterior Cruciate Ligament-Reconstructed Knees: Untreated Versus Repair Versus Partial Meniscectomy

BACKGROUND

Lateral meniscal oblique radial tears (LMORTs) affect joint and meniscal stability in anterior cruciate ligament (ACL)-deficient knees.

PURPOSE

To determine the clinically relevant kinematics associated with the most common posterior horn LMORT lesion types, types 3 (LMORT3) and 4 (LMORT4), untreated versus arthroscopic repair versus partial meniscectomy in combination with ACL reconstruction (ACLR).

STUDY

Controlled laboratory study.

METHODS

Sixteen cadaveric knees underwent robotic testing for anterior drawer and pivot-shift simulations at multiple knee flexion angles in ACL-intact and ACL-deficient states, followed by sequential testing of arthroscopic ACLR, LMORT3 lesion, LMORT3 repair, and partial meniscectomy (n = 8). The same testing sequence was performed for LMORT4 lesions (n = 8).

RESULTS

ACLR restored kinematics in ACL-deficient knees to intact levels for all metrics tested. For anterior drawer, ACLR + LMORT3 tear and partial meniscectomy resulted in significantly greater anterior translation compared with ACL-intact at all angles (P < .05) and compared with ACLR at 60° and 90° (P < .014). For pivot shift, compared with ACL-intact knees, ACLR + LMORT3 tear resulted in significantly more anterior translation at 15° (P = .041); and for ACLR + partial meniscectomy, at both 0° and 15° (P < .03). ACLR + LMORT4 tear and partial meniscectomy resulted in significantly greater anterior translation for anterior drawer (P < .04) and pivot-shift testing (P < .05) compared with intact and ACLR knees at all angles tested. ACLR + LMORT3 repair and ACLR + LMORT4 repair restored kinematics to ACLR and intact levels at all angles tested. ACLR + LMORT3 tear (P < .008) and both LMORT4 tear and partial meniscectomy (P < .05) resulted in increased meniscal extrusion compared with intact and ACLR statuses at all tested angles for anterior drawer and pivot shift, while repairs restored meniscal stability to ACLR and intact levels.

CONCLUSION

Untreated LMORT tears increased anterior translation, pivot shift, and meniscal extrusion after ACLR, while partial meniscectomy further exacerbated these detrimental effects in this cadaveric model. In contrast, arthroscopic side-to-side repair of LMORT lesions effectively restored measured knee kinematics.

CLINICAL RELEVANCE

LMORT lesions are common with ACL tears and adversely affect joint stability and meniscal extrusion. This study highlights the importance of repair of LMORT 3 and 4 lesions at the time of ACLR.

Grade III pivot shift as an early sign of knee decompensation in chronic ACL-injured knees with bimeniscal tears

PURPOSE

To analyse possible associations between the preoperative pivot shift (PS) test and both patient and injury characteristics in anterior cruciate ligament (ACL)-injured knees, considering previously neglected meniscal injuries such as ramp and root tears. The hypothesis was that a preoperative grade III PS was associated with the amount of intra-articular soft-tissue damage and chronicity of the injury.

METHODS

The cohort involved 376 patients who underwent primary ACL reconstruction (239 males/137 females; median age 26). Patients were examined under anesthesia before surgery, using the PS test. During arthroscopy, intra-articular soft-tissue damage of the injured knee was classified as: (1) partial ACL tear; (2) complete isolated ACL tear; (3) complete ACL tear with one meniscus tear; and (4) complete ACL and bimeniscal tears. Chi-square and Mann-Whitney U tests were used to evaluate whether sex, age, body mass index, sport at injury, mechanism of injury, time from injury and intra-articular damage (structural damage of ACL and menisci) were associated with a grade III PS. Intra-articular damage was further analyzed for two sub-cohorts: acute (time from injury ≤ 6 months) and chronic injuries (> 6 months).

RESULTS

A grade III PS test was observed in 26% of patients. A significant association with PS grading was shown for age, time from injury and intra-articular soft-tissue damage (p < 0.05). Further analyses showed that grade III PS was associated with intra-articular damage in chronic injuries only (p < 0.01). In complete ACL and bimeniscal tears, grade III PS was more frequent in chronic (53%) than in acute knee injuries (26%; p < 0.01). Patients with chronic complete ACL and bimeniscal tears had a grade III PS 3.3 [1.3-8.2] times more often than patients in the acute sub-cohort.

CONCLUSION

In ACL-injured patients, a preoperative grade III PS was mainly associated with a higher amount of intra-articular soft-tissue damage and chronicity of the injury. Patients with complete chronic ACL injuries and bimeniscal tears were more likely to have a preoperative grade III PS than their acute counterparts. This suggests that grade III PS may be an early sign of knee decompensation of dynamic rotational knee laxity in chronic ACL-injured knees with bimeniscal lesions.

LEVEL OF EVIDENCE

Level III.

A larger side-to-side difference in anterior knee laxity increases the prevalence of medial and lateral meniscal injuries in patients with ACL injuries

PURPOSE

The objective of this study was to investigate factors that influence the prevalence of medial and lateral meniscal injuries at the time of anterior cruciate ligament (ACL) reconstruction in patients with ACL injuries.

METHODS

Patients with ACL injuries at 9 institutions were enrolled in this multicentre study. Age, sex, duration between injury and surgery, pivot shift test grade, anterior knee laxity determined using the Kneelax 3 arthrometer, and other variables were assessed by logistic regression analysis. Meniscal conditions were evaluated via arthroscopy.

RESULTS

In all, 830 patients were enrolled. The prevalence of medial and lateral meniscal tears was 32.0% (266 knees) and 26.5% (220 knees), respectively. Significant factors that influenced the prevalence of medial meniscal injuries were age [odds ratio (OR) 1.03; P = 0.000], side-to-side differences in instrumented anterior knee laxity before surgery (OR 1.12; P = 0.002), duration between injury and surgery (≥ 12 months) (OR 1.86; P = 0.023), and pivot shift test grade (OR 1.36; P = 0.014). Significant factors of lateral meniscal injury were side-to-side differences in anterior knee laxity before surgery (OR 1.12; P = 0.003) and the male sex (OR 1.50; P = 0.027).

CONCLUSION

Greater anterior knee laxity, age, a longer duration between injury and surgery, and a higher pivot shift test grade predicted medial meniscal injury. Greater anterior knee laxity and the male sex predicted lateral meniscal injury. In patients with ACL injuries, the importance of side-to-side differences in anterior knee laxity should be rediscovered from the viewpoint of meniscal conditions.

LEVEL OF EVIDENCE

Level III.

High incidence of superficial and deep medial collateral ligament injuries in 'isolated' anterior cruciate ligament ruptures: a long overlooked injury

PURPOSE

In anterior cruciate ligament (ACL) injuries, concomitant damage to peripheral soft tissues is associated with increased rotatory instability of the knee. The purpose of this study was to investigate the incidence and patterns of medial collateral ligament complex injuries in patients with clinically 'isolated' ACL ruptures.

METHODS

Patients who underwent ACL reconstruction for complete 'presumed isolated' ACL rupture between 2015 and 2019 were retrospectively included in this study. Patient's characteristics and intraoperative findings were retrieved from clinical and surgical documentation. Preoperative MRIs were evaluated and the grade and location of injuries to the superficial MCL (sMCL), dMCL and the posterior oblique ligament (POL) recorded. All patients were clinically assessed under anaesthesia with standard ligament laxity tests.

RESULTS

Hundred patients with a mean age of 22.3 ± 4.9 years were included. The incidence of concomitant MCL complex injuries was 67%. sMCL injuries occurred in 62%, dMCL in 31% and POL in 11% with various injury patterns. A dMCL injury was significantly associated with MRI grade II sMCL injuries, medial meniscus 'ramp' lesions seen at surgery and bone oedema at the medial femoral condyle (MFC) adjacent to the dMCL attachment site (p < 0.01). Logistic regression analysis identified younger age (OR 1.2, p < 0.05), simultaneous sMCL injury (OR 6.75, p < 0.01) and the presence of bone oedema at the MFC adjacent to the dMCL attachment site (OR 5.54, p < 0.01) as predictive factors for a dMCL injury.

CONCLUSION

The incidence of combined ACL and medial ligament complex injuries is high. Lesions of the dMCL were associated with ramp lesions, MFC bone oedema close to the dMCL attachment, and sMCL injury. Missed AMRI is a risk factor for ACL graft failure from overload and, hence, oedema in the MCL (especially dMCL) demands careful assessment for AMRI, even in the knee lacking excess valgus laxity. This study provides information about specific MCL injury patterns including the dMCL in ACL ruptures and will allow surgeons to initiate individualised treatment.

LEVEL OF EVIDENCE

III.

Advanced rehabilitation technology in orthopaedics-a narrative review

INTRODUCTION

As the demand for rehabilitation in orthopaedics increases, so too has the development in advanced rehabilitation technology. However, to date, there are no review papers outlining the broad scope of advanced rehabilitation technology used within the orthopaedic population. The aim of this study is to identify, describe and summarise the evidence for efficacy for all advanced rehabilitation technologies applicable to orthopaedic practice.

METHODS

The relevant literature describing the use of advanced rehabilitation technology in orthopaedics was identified from appropriate electronic databases (PubMed and EMBASE) and a narrative review undertaken.

RESULTS

Advanced rehabilitation technologies were classified into two groups: hospital-based and home-based rehabilitation. In the hospital-based technology group, we describe the use of continuous passive motion and robotic devices (after spinal cord injury) and their effect on improving clinical outcomes. We also report on the use of electromagnetic sensor technology for measuring kinematics of upper and lower limbs during rehabilitation. In the home-based technology group, we describe the use of inertial sensors, smartphones, software applications and commercial game hardware that are relatively inexpensive, user-friendly and widely available. We outline the evidence for videoconferencing for promoting knowledge and motivation for rehabilitation as well as the emerging role of virtual reality.

CONCLUSIONS

The use of advanced rehabilitation technology in orthopaedics is promising and evidence for its efficacy is generally supportive.

An Anterior Cruciate Ligament In Vitro Rupture Model Based on Clinical Imaging

BACKGROUND

Biomechanical studies on anterior cruciate ligament (ACL) injuries and reconstructions are based on ACL transection instead of realistic injury trauma.

PURPOSE

To replicate an ACL injury in vitro and compare the laxity that occurs with that after an isolated ACL transection injury before and after ACL reconstruction.

STUDY DESIGN

Controlled laboratory study.

METHODS

Nine paired knees were ACL injured or ACL transected. For ACL injury, knees were mounted in a rig that imposed tibial anterior translation at 1000 mm/min to rupture the ACL at 22.5° of flexion, 5° of internal rotation, and 710 N of joint compressive force, replicating data published on clinical bone bruise locations. In contralateral knees, the ACL was transected arthroscopically at midsubstance. Both groups had ACL reconstruction with bone-patellar tendon-bone graft. Native, ACL-deficient, and reconstructed knee laxities were measured in a kinematics rig from 0° to 100° of flexion with optical tracking: anterior tibial translation (ATT), internal rotation (IR), anterolateral (ATT + IR), and pivot shift (IR + valgus).

RESULTS

The ACL ruptured at 26 ± 5 mm of ATT and 1550 ± 620 N of force (mean ± SD) with an audible spring-back tibiofemoral impact with 5^o of valgus. ACL injury and transection increased ATT (P < .001). ACL injury caused greater ATT than ACL transection by 1.4 mm (range, 0.4-2.2 mm; P = .033). IR increased significantly in ACL-injured knees between 0° and 30° of flexion and in ACL transection knees from 0° to 20° of flexion. ATT during the ATT + IR maneuver was increased by ACL injury between 0° and 80° and after ACL transection between 0° and 60°. Residual laxity persisted after ACL reconstruction from 0° to 40° after ACL injury and from 0° to 20° in the ACL transection knees. ACL deficiency increased ATT and IR in the pivot-shift test (P < .001). The ATT in the pivot-shift increased significantly at 0° to 20° after ACL transection and 0° to 50° after ACL injury, and this persisted across 0° to 20° and 0° to 40° after ACL reconstruction.

CONCLUSION

This study developed an ACL injury model in vitro that replicated clinical ACL injury as evidenced by bone bruise patterns. ACL injury caused larger increases of laxity than ACL transection, likely because of damage to adjacent tissues; these differences often persisted after ACL reconstruction.

CLINICAL RELEVANCE

This in vitro model created more realistic ACL injuries than surgical transection, facilitating future evaluation of ACL reconstruction techniques.

The quantitative evaluation of anterior drawer test using an electromagnetic measurement system

The anterior drawer test (ADT) is the gold standard examination for the diagnosis of anterior talofibular ligamentinsufficiency,although there is noquantitative evaluation of ADT that is generally usable and reliable.An electromagnetic sensor (EMS)has been used to quantitatively evaluate joint kinematics, and has a high potential to be applied to the ankle joint. The aim of this study was to validatethe EMS measurement of the ADTin comparison to the fluoroscopic evaluationand to evaluate the reproducibility of the EMS measurement.Six feet were included,and an examinerperformed the ADT5 times for each foot while the anterior translation of the ankle jointwas quantitative evaluatedusing EMS and fluoroscope simultaneously. The anterior translation of the ankle joint during the ADT in EMS and in fluoroscope was 8.1 ± 5.7 mm and 3.6 ± 2.4 mm.Astrong correlation was observed between the measurements using EMS and fluoroscope (p < 0.01, the correlation coefficient = 0.91). Another 20 feet were included, and three examiners performed the ADT five times for each foot with the EMS measurement. The intra and inter-examiner reliability was 0.99 and 0.89.The EMS could quantify the anterior translation during the ADT which corresponds to fluoroscopic evaluation.

[Relevance of meniscus loss for the progression of osteoarthritis and treatment options for early arthritis]

Meniscal tears are still one of the most frequent lesions in the knee joint. The relevance of meniscus loss for the development of osteoarthritis is undisputed. Meniscus repair, replacement and transplantation play an important role in the treatment of early arthritis, especially when they are a part of a master plan including alignment correction, stabilization and cartilage surgery, if needed. Scientific data show evidence concerning the protection of osteoarthritis, even though a lack of studies including comparison groups has to be admitted.

Association of Ligamentous Laxity, Male Sex, Chronicity, Meniscal Injury, and Posterior Tibial Slope With a High-Grade Preoperative Pivot Shift: A Post Hoc Analysis of the STABILITY Study

Background:

A spectrum of anterolateral rotatory laxity exists in anterior cruciate ligament (ACL)–injured knees. Understanding of the factors contributing to a high-grade pivot shift continues to be refined.

Purpose:

To investigate factors associated with a high-grade preoperative pivot shift and to evaluate the relationship between this condition and baseline patient-reported outcome measures (PROMs).

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

A post hoc analysis was performed of 618 patients with ACL deficiency deemed high risk for reinjury. A binary logistic regression model was developed, with high-grade pivot shift as the dependent variable. Age, sex, Beighton score, chronicity of the ACL injury, posterior third medial or lateral meniscal injury, and tibial slope were selected as independent variables. The importance of knee hyperextension as a component of the Beighton score was assessed using receiver operator characteristic curves. Baseline PROMs were compared between patients with and without a high-grade pivot.

Results:

Six factors were associated with a high-grade pivot shift: Beighton score (each additional point; odds ratio [OR], 1.17; 95% CI, 1.06-1.30; P = .002), male sex (OR, 2.30; 95% CI, 1.28-4.13; P = .005), presence of a posterior third medial (OR, 2.55; 95% CI, 1.11-5.84; P = .03) or lateral (OR, 1.76; 95% CI, 1.01-3.08; P = .048) meniscal injury, tibial slope >9° (OR, 2.35; 95% CI, 1.09-5.07; P = .03), and chronicity >6 months (OR, 1.70; 95% CI, 1.00-2.88; P = .049). The presence of knee hyperextension improved the diagnostic utility of the Beighton score as a predictor of a high-grade pivot shift. Tibial slope <9° was associated with only a high-grade pivot in the presence of a posterior third medial meniscal injury. Patients with a high-grade pivot shift had higher baseline 4-Item Pain Intensity Measure scores than did those without a high-grade pivot shift (mean ± SD, 11 ± 13 vs 8 ± 14; P = .04); however, there was no difference between groups in baseline International Knee Documentation Committee, ACL Quality of Life, Knee injury and Osteoarthritis Outcome Score, or Knee injury and Osteoarthritis Outcome Score subscale scores.

Conclusion:

Ligamentous laxity, male sex, posterior third medial or lateral meniscal injury, increased posterior tibial slope, and chronicity were associated with a high-grade pivot shift in this population deemed high risk for repeat ACL injury. The effect of tibial slope may be accentuated by the presence of meniscal injury, supporting the need for meniscal preservation. Baseline PROMs were similar between patients with and without a high-grade pivot shift.

Treatment after anterior cruciate ligament injury: Panther Symposium ACL Treatment Consensus Group

Treatment strategies for anterior cruciate ligament (ACL) injuries continue to evolve. Evidence supporting best practice guidelines for the management of ACL injury is to a large extent based on studies with low-level evidence. An international consensus group of experts was convened to collaboratively advance towards consensus opinions regarding the best available evidence on operative versus non-operative treatment for ACL injury.The purpose of this study was to report the consensus statements on operative versus non-operative treatment of ACL injuries developed at the ACL Consensus Meeting Panther Symposium 2019. Sixty-six international experts on the management of ACL injuries, representing 18 countries, convened and participated in a process based on the Delphi method of achieving consensus. Proposed consensus statements were drafted by the Scientific Organising Committee and Session Chairs for the three working groups. Panel participants reviewed preliminary statements prior to the meeting and provided initial agreement and comments on the statement via online survey. During the meeting, discussion and debate occurred for each statement, after which a final vote was then held. Eighty per cent agreement was defined a priori as consensus. A total of 11 of 13 statements on operative veresus non-operative treatment of ACL injury reached consensus during the symposium. Nine statements achieved unanimous support; two reached strong consensus; one did not achieve consensus; and one was removed due to redundancy in the information provided.In highly active patients engaged in jumping, cutting and pivoting sports, early anatomical anterior cruciate ligament reconstruction (ACLR) is recommended due to the high risk of secondary meniscus and cartilage injuries with delayed surgery, although a period of progressive rehabilitation to resolve impairments and improve neuromuscular function is recommended. For patients who seek to return to straight plane activities, non-operative treatment with structured, progressive rehabilitation is an acceptable treatment option. However, with persistent functional instability or when episodes of giving way occur, anatomical ACLR is indicated. The consensus statements derived from international leaders in the field will assist clinicians in deciding between operative and non-operative treatment with patients after an ACL injury.Level of evidence: V.

Age, activity level and meniscus injury, but not tear location, tibial slope or anterolateral ligament injury predict coping with anterior cruciate ligament injury

INTRODUCTION

Early recognition of potential predictors on the success of conservative treatment of anterior cruciate ligament (ACL) is important, as appropriate treatment can be applied to each individual patient. The goal of this study is to assess the patient demographic and radiological parameters that predict coping with ACL injuries.

METHODS

All patients presenting with a complete ACL injury between 2014 and 2018 at our clinic were included. The role of patient demographics (age, gender, activity level, meniscus injury and time from injury to clinic), and ACL tear location, bone bruises, tibial slope, and anterolateral ligament (ALL) injury were assessed on the success of conservative treatment using univariate and multivariate analyses.

RESULTS

Sixty-five patients (32%) were copers and 141 (68%) were non-copers. Univariate analysis showed that copers were significantly older (40 vs. 27 years, P < 0.001), had lower preinjury activity level (Tegner 5.7 vs. 6.5, P < 0.001) and less often lateral meniscus tears (16% vs. 5%, P = 0.019) but not medial meniscus tears (17% vs. 14%, P = 0.609) than non-copers. Multivariate analysis revealed that increasing age (P < 0.001), Tegner level ≤ 6 (P = 0.003) and no meniscus injury (P = 0.045) were independent predictors of coping with ACL deficiency.

CONCLUSIONS

Older age, participation in lower activity sports levels and absence of meniscus injury were predictive of coping with ACL deficiency, whereas there was no such role for tear location, tibial slope, lateral bone bruise presence, ALL injury or gender. These findings might help to identify potential copers and guide surgeons early in the optimal treatment for patients with ACL injury.

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.

Remnant preservation provides good clinical outcomes after anterior cruciate ligament reconstruction

PURPOSE

To evaluate the association of remnant preservation (RP) and non-RP (NRP) with patient-reported outcome measures and subsequent graft rupture at a minimum 2-year follow-up after anterior cruciate ligament (ACL) reconstruction.

METHODS

Patients in this retrospective study underwent primary isolated ACL reconstruction by the RP or NRP technique with a four- to five-strand hamstring tendon graft. Multivariate linear or logistic regression and Cox regression analyses were performed to compare the physical and psychological outcomes by the International Knee Documentation Committee subjective knee form (IKDC-SKF) and the Japanese Anterior Cruciate Ligament questionnaire 25 (JACL-25), respectively; satisfaction rate; and prognosticators of graft rupture.

RESULTS

In total, 120 patients (mean age, 30.6 ± 12.7 years; 54 RP, 66 NRP) with a mean follow-up of 3.2 ± 1.6 years were enrolled in this study. At the latest postoperative follow-up, the RP group showed a mean IKDC-SKF score of 92.3 ± 8.5 and mean JACL-25 score of 13.2 ± 11.2, while these scores in the NRP group were 86.4 ± 12.2 and 24.4 ± 19.5, respectively (P = 0.016 and 0.007, respectively). No significant differences were found in the return-to-sports rate (RP vs. NRP, 79.5% vs. 67.5%) or satisfaction rate (RP vs. NRP, 89.2% vs. 74.4%) (n.s.); however, a significant difference was found in the rate of return to the preinjury sports level (RP vs. NRP, 64.1% vs. 37.5%; P = 0.014). The graft rupture rate was significantly higher in the NRP than RP group (9/66 vs. 1/54; hazard ratio 9.29; 95% confidence interval 1.04-82.81). Younger age (≤ 18 years) was the other important risk factor for graft rupture (hazard ratio 8.67; 95% confidence interval 2.02-37.13).

CONCLUSION

Patients who underwent ACL reconstruction with the RP technique obtained somewhat better physical and psychological results than those who underwent ACL reconstruction with the NRP technique. With respect to clinical relevance, patients treated with the RP technique may obtain better outcomes in terms of graft rupture and return to the preinjury sports level than those treated with the NRP technique, but with no differences in overall return to sports or satisfaction.

LEVEL OF EVIDENCE

IV.

Unrepaired lateral meniscus tears lead to remaining pivot-shift in ACL-reconstructed knees

PURPOSE

To compare the postoperative rotatory knee laxity between ACL-reconstructed knees with different meniscus treatments using an electromagnetic pivot-shift measurement.

METHODS

Forty-six patients with unilateral ACL reconstructions were enrolled (21 males/25 females, 25 ± 12 y.o.). Concomitant meniscus tears, if any, were repaired whenever possible during primary ACL reconstruction. At 1 year postoperatively, pivot-shift test was performed under anaesthesia during screw removal surgery and quantitatively evaluated by tibial acceleration using an electromagnetic system. The acceleration was compared between ACL-reconstructed knees with different meniscal treatments: intact, repaired and unrepaired.

RESULTS

A concomitant meniscus tear was found in 28 knees preoperatively: lateral tears in 11 knees, medial tears in 11 knees and both medial and lateral tears in 6 knees. Postoperatively, 19 ACL-reconstructed knees had a repaired meniscus for either medial, lateral or bilateral menisci tears, and 18 knees had intact menisci pre- and post-operatively. Meanwhile, nine lateral meniscus tears were irreparable and treated by partial meniscectomy or left in situ. ACL-reconstructed knees with unrepaired lateral menisci had significantly larger pivot-shift acceleration (0.9 ± 0.7 m/s²) than those with intact menisci (0.5 ± 0.2 m/s², p < 0.05), whereas rotatory knee laxity was similar between the knees with fully repaired menisci (0.6 ± 0.3 m/s²) and intact menisci (n.s.).

CONCLUSION

An unrepaired lateral meniscus tear in an ACL-reconstructed knee could lead to remaining pivot-shift postoperatively. A concomitant meniscus tear should be repaired during ACL reconstruction to restore normal rotational laxity.

LEVEL OF EVIDENCE

Therapeutic Study, Level III.

Objectifying the Pivot Shift Test

The pivot shift test is utilized for assessment of rotatory instability in the anterior cruciate ligament (ACL) deficient knee. There are multiple reports of the pivot shift maneuver, and there is a lack of consensus among clinicians as to a standardized maneuver. Measurement devices are a feasible option to evaluate rotatory knee instability, objectively or quantitatively. Traditionally, measurement systems have been invasive systems. More recently, electromagnetic system, inertial sensor, or imaging analysis systems, specifically with the utilization of a tablet computer, have emerged as noninvasive, and more importantly, validated options. It is important to recognize that anatomic structures other than the ACL contribute to rotatory knee stability. Addressing the tibial slope, anterolateral structures of the knee, specifically the iliotibial band, and menisci during ACL surgery may decrease residual pivot shift in an attempt to improve clinical outcomes and prevent reinjury. This review article describes the pivot shift maneuver, objective measurement tools, and clinical applications of the pivot shift test.

Risk Factors for Grade 3 Pivot Shift in Knees With Acute Anterior Cruciate Ligament Injuries: A Comprehensive Evaluation of the Importance of Osseous and Soft Tissue Parameters From the SANTI Study Group

BACKGROUND

Preoperative grade 3 pivot shift has been reported to be associated with higher rates of anterior cruciate ligament (ACL) failure, persistent instability, and inferior patient-reported outcomes. The etiology of a high-grade pivot shift is multifactorial, and numerous factors have been suggested to be responsible. More attention has recently been focused on injury to the anterolateral structures (ALS) as a risk factor for a grade 3 pivot shift.

PURPOSE

To determine risk factors for grade 3 pivot shift, including soft tissue and osseous parameters.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A prospective evaluation was undertaken of 200 consecutive patients undergoing acute ACL reconstruction (within 10 days of injury). An open exploration of the lateral side of the injured knee was performed at the time of the index procedure. Details regarding patient and injury characteristics were recorded, as were details of soft tissue injuries, including meniscal tears, ALS lesions, medial collateral ligament tears, and chondral injuries. Osseous parameters (tibial slope and condylar ratios) were determined per established magnetic resonance imaging protocols. A multivariate logistic regression with penalized maximum likelihood was used to identify risk factors associated with International Knee Documentation Committee (IKDC) grade 3 pivot shift.

RESULTS

The mean ± SD age of the population was 28.3 ± 9.8 years; 67.5% of patients were male. Among patients, 35 (17.5%) had a high-grade pivot shift (IKDC grade 3), and 165 (82.5%) had a low-grade pivot shift (IKDC grades 1 and 2). Univariate and multivariate logistic regression analysis demonstrated that injury to the ALS was the only significant risk factor for grade 3 pivot shift (odds ratio, 13.49; 95% CI, 1.80-1725.53).

CONCLUSION

This comprehensive evaluation of soft tissue and osseous factors has identified that injury to the ALS is the most important risk factor for grade 3 pivot shift in acute ACL-injured knees.

Treatment after ACL injury: Panther Symposium ACL Treatment Consensus Group

Treatment strategies for ACL injuries continue to evolve. Evidence supporting best practice guidelines to manage ACL injury is largely based on studies with low-level evidence. An international consensus group of experts was convened determine consensus regarding best available evidence on operative versus non-operative treatment for ACL injury. The purpose of this study is to report the consensus statements on operative versus non-operative treatment of ACL injuries developed at the ACL Consensus Meeting Panther Symposium 2019. Sixty-six international experts on the management of ACL injuries, representing 18 countries, convened and participated in a process based on the Delphi method of achieving consensus. Proposed consensus statements were drafted by the Scientific Organising Committee and Session Chairs. Panel participants reviewed preliminary statements prior to the meeting and provided initial agreement and comments on the statement via online survey. During the meeting, discussion and debate occurred for each statement, after which a final vote was then held. Eighty per cent agreement was defined a priori as consensus. A total of 11 of 13 statements on operative versus non-operative treatment of ACL injury reached consensus during the Symposium. Nine statements achieved unanimous support, two reached strong consensus, one did not achieve consensus, and one was removed due to redundancy in the information provided. In highly active patients engaged in jumping, cutting and pivoting sports, early anatomical ACL reconstruction is recommended due to the high risk of secondary meniscus and cartilage injuries with delayed surgery, although a period of progressive rehabilitation to resolve impairments and improve neuromuscular function is recommended. For patients who seek to return to straight plane activities, non-operative treatment with structured, progressive rehabilitation is an acceptable treatment option. However, with persistent functional instability, or when episodes of giving way occur, anatomical ACL reconstruction is indicated. The consensus statements derived from international leaders in the field may assist clinicians in deciding between operative and non-operative treatment with patients after an ACL injury. Level of evidence: Level V

Patient-Reported and Quantitative Outcomes of Anatomic Anterior Cruciate Ligament Reconstruction With Hamstring Tendon Autografts

Background:

The pivot-shift test has become more consistent and reliable and is a meaningful outcome measurement after anterior cruciate ligament reconstruction (ACLR).

Purpose/Hypothesis:

The purpose of this investigation was to assess patient-reported outcomes (PROs) and the quantitative pivot shift (QPS) preoperatively, at time zero immediately after anatomic ACLR, and after 24 months as well as the relationship between PROs and the QPS. It was hypothesized that anatomic ACLR would restore rotatory stability measured by the pivot-shift test and that QPS measurements would be positively correlated with PROs.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

The ACL-injured and contralateral uninjured knees from 89 of 107 (83.2%) enrolled patients at 4 international centers were evaluated using a standardized pivot-shift test. Tibial acceleration was assessed with an inertial sensor, and lateral compartment translation was measured using an image analysis system preoperatively, at time zero immediately postoperatively, and at follow-up after 2 years. PROs were assessed at 12 and 24 months postoperatively with the International Knee Documentation Committee (IKDC) subjective knee form, Cincinnati Knee Rating System (CKRS), Marx activity rating scale, and activity of daily living score (ADLS).

Results:

The mean patient age at surgery was 27 years (range, 15-45 years). A positive pivot shift preoperatively (side-to-side difference in tibial acceleration, 2.6 ± 4.0 m/s²; side-to-side difference in anterior tibial translation, 2.0 ± 2.0 mm) was reduced at time zero postoperatively (side-to-side difference in tibial acceleration, –0.5 ± 1.3 m/s²; side-to-side difference in anterior tibial translation, –0.1 ± 1.0 mm). All PROs improved from preoperatively to final follow-up at 24 months: from 56.5 to 85.5 points for the IKDC (P = .0001), from 28.8 to 32.4 points for the CKRS (P = .04), from 11.2 to 7.9 points for the Marx (P < .0001), and from 75.7 to 91.6 points for the ADLS (P < .0001). Neither preoperative nor time zero postoperative rotatory laxity assessed by the pivot-shift test correlated with PROs at 24-month follow-up. A graft retear was observed in 4 patients (4.5%) within 2 years of follow-up.

Conclusion:

Anatomic ACLR resulted in significantly improved and acceptable PROs at 2-year follow-up and a low failure rate. Anatomic ACLR restored QPS measurements of anterior tibial translation and tibial acceleration to those of the contralateral knee immediately after surgery while still under anesthesia, but there was no correlation between the QPS preoperatively or at time zero after ACLR and PROs at 2-year follow-up.

Treatment After Anterior Cruciate Ligament Injury: Panther Symposium ACL Treatment Consensus Group

Treatment strategies for anterior cruciate ligament (ACL) injuries continue to evolve. Evidence supporting best-practice guidelines for the management of ACL injury is to a large extent based on studies with low-level evidence. An international consensus group of experts was convened to collaboratively advance toward consensus opinions regarding the best available evidence on operative versus nonoperative treatment for ACL injury. The purpose of this study was to report the consensus statements on operative versus nonoperative treatment of ACL injuries developed at the ACL Consensus Meeting Panther Symposium 2019. There were 66 international experts on the management of ACL injuries, representing 18 countries, who were convened and participated in a process based on the Delphi method of achieving consensus. Proposed consensus statements were drafted by the scientific organizing committee and session chairs for the 3 working groups. Panel participants reviewed preliminary statements before the meeting and provided initial agreement and comments on the statement via online survey. During the meeting, discussion and debate occurred for each statement, after which a final vote was then held. Ultimately, 80% agreement was defined a priori as consensus. A total of 11 of 13 statements on operative versus nonoperative treatment of ACL injury reached consensus during the symposium. Overall, 9 statements achieved unanimous support, 2 reached strong consensus, 1 did not achieve consensus, and 1 was removed because of redundancy in the information provided. In highly active patients engaged in jumping, cutting, and pivoting sports, early anatomic ACL reconstruction is recommended because of the high risk of secondary meniscal and cartilage injuries with delayed surgery, although a period of progressive rehabilitation to resolve impairments and improve neuromuscular function is recommended. For patients who seek to return to straight-plane activities, nonoperative treatment with structured, progressive rehabilitation is an acceptable treatment option. However, with persistent functional instability, or when episodes of giving way occur, anatomic ACL reconstruction is indicated. The consensus statements derived from international leaders in the field will assist clinicians in deciding between operative and nonoperative treatment with patients after an ACL injury.

Editorial Commentary: So Your Knee Has a Big Pivot Shift Before Anterior Cruciate Ligament Surgery-Why Does that Matter???

Control of anterolateral knee laxity has always been a major goal of anterior cruciate ligament (ACL) reconstruction. The recent focus on the anatomy of the anterolateral knee and new studies demonstrating decreased graft failure risk with the additional of lateral procedures to intra-articular ACL reconstruction have given these procedures new relevance. A key question that drives indications is which patients benefit the most from these procedures. Those patients with increased rotational knee laxity, particularly in the absence of a repairable meniscus injury, may be good candidates. ACL injury chronicity, bony anatomy, concomitant anterolateral injury, and other factors all contribute to increased anterolateral knee laxity. This high laxity population is ideal for evaluation of the effectiveness of new methods to control knee laxity and improve outcomes of isolated intra-articular ACL reconstruction.

The Influences of Chronicity and Meniscal Injuries on Pivot Shift in Anterior Cruciate Ligament-Deficient Knees: Quantitative Evaluation Using an Electromagnetic Measurement System

PURPOSE

To investigate the influences of time from injury to surgery and meniscal injuries on knee rotational laxity in anterior cruciate ligament (ACL)-deficient knees using the electromagnetic system retrospectively.

METHODS

Ninety-four unilateral ACL-injured patients (44 male and 50 female, mean age: 27.3 ± 11.8 years) were included. The pivot-shift test was performed before ACL reconstruction, as was a quantitative evaluation using the electromagnetic system to determine tibial acceleration. Patients were divided into 4 groups according to the chronicity: group 1, within 3 months (22 patients); group 2, between 3 and 6 months (29 patients); group 3, between 6 and 12 months (23 patients); and group 4, more than 12 months (20 patients). The presence of meniscal injuries was examined arthroscopically.

RESULTS

The tibial acceleration was significantly greater in group 4. There was a positive correlation between tibial acceleration and the time from injury to surgery (r = 0.47, P = .02). In groups 1, 2 and 3, the tibial acceleration in patients with a lateral meniscal injury was significantly greater than in patients with a medial meniscal injury and without meniscal injury. When patients with lateral meniscal injury were excluded (leaving those with medial meniscus injury or without meniscal injury), group 4 had significantly greater accelerations than other groups.

CONCLUSIONS

In ACL-deficient knees, rotational laxity increased with time and the increased rotational laxity was evident more than 1 year after injury whereas it increased with concomitant lateral meniscal injuries within 1 year after injury.

LEVEL OF EVIDENCE

Ⅳ, diagnostic study of nonconsecutive patients.

Rotatory Knee Laxity Exists on a Continuum in Anterior Cruciate Ligament Injury

BACKGROUND

The purpose of this investigation was to compare the magnitude of rotatory knee laxity in patients with a partial anterior cruciate ligament (ACL) tear, those with a complete ACL tear, and those who had undergone a failed ACL reconstruction. It was hypothesized that rotatory knee laxity would increase with increasing injury grade, with knees with partial ACL tears demonstrating the lowest rotatory laxity and knees that had undergone failed ACL reconstruction demonstrating the highest rotatory laxity.

METHODS

A prospective multicenter study cohort of 354 patients who had undergone ACL reconstruction between 2012 and 2018 was examined. All patients had both injured and contralateral healthy knees evaluated using standardized, preoperative quantitative pivot shift testing, determined by a validated, image-based tablet software application and a surface-mounted accelerometer. Quantitative pivot shift was compared with the contralateral healthy knee in 20 patients with partial ACL tears, 257 patients with complete ACL tears, and 27 patients who had undergone a failed ACL reconstruction. Comparisons were made using 1-way analysis of variance (ANOVA) with post hoc 2-sample t tests with Bonferroni correction. Significance was set at p < 0.05.

RESULTS

There were stepwise increases in side-to-side differences in quantitative pivot shift in terms of lateral knee compartment translation for patients with partial ACL tears (mean [and standard deviation], 1.4 ± 1.5 mm), those with complete ACL tears (2.5 ± 2.1 mm), and those who had undergone failed ACL reconstruction (3.3 ± 1.9 mm) (p = 0.01) and increases in terms of lateral compartment acceleration for patients with partial ACL tears (0.7 ± 1.4 m/s), those with complete ACL tears (2.3 ± 3.1 m/s), and those who had undergone failed ACL reconstruction (2.4 ± 5.5 m/s) (p = 0.01). A significant difference in lateral knee compartment translation was found when comparing patients with partial ACL tears and those with complete ACL tears (1.2 ± 2.1 mm [95% confidence interval (CI), 0.2 to 2.1 mm]; p = 0.02) and patients with partial ACL tears and those who had undergone failed ACL reconstruction (1.9 ± 1.7 mm [95% CI, 0.8 to 2.9 mm]; p = 0.001), but not when comparing patients with complete ACL tears and those who had undergone failed ACL reconstruction (0.8 ± 2.1 [95% CI, -0.1 to 1.6 mm]; p = 0.09). Increased lateral compartment acceleration was found when comparing patients with partial ACL tears and those with complete ACL tears (1.5 ± 3.0 m/s [95% CI, 0.8 to 2.3 m/s]; p = 0.0002), but not when comparing patients with complete ACL tears and those who had undergone failed ACL reconstruction (0.1 ± 3.4 m/s [95% CI, -2.2 to 2.4 m/s]; p = 0.93) or patients with partial ACL tears and those who had undergone failed ACL reconstruction (1.7 ± 4.2 m/s [95% CI, -0.7 to 4.0 m/s]; p = 0.16). An increasing lateral compartment translation of the contralateral, ACL-healthy knee was found in patients with partial ACL tears (0.8 mm), those with complete ACL tears (1.2 mm), and those who had undergone failed ACL reconstruction (1.7 mm) (p < 0.05).

CONCLUSIONS

A progressive increase in rotatory knee laxity, defined by side-to-side differences in quantitative pivot shift, was observed in patients with partial ACL tears, those with complete ACL tears, and those who had undergone failed ACL reconstruction. These results may be helpful when assessing outcomes and considering indications for the management of high-grade rotatory knee laxity.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Triaxial accelerometer evaluation is correlated with IKDC grade of pivot shift

PURPOSE

The purpose of this study was to evaluate the correlation between tibial acceleration parameters measured by the KiRA device and the clinical grade of pivot shift. The secondary objective was to report the risk factors for pre-operative high-grade pivot shift.

METHODS

Two-hundred and ninety-five ACL deficient patients were examined under anesthesia. The pivot shift tests were performed twice by an expert surgeon. Clinical grading was performed using the International Knee Documentation Committee (IKDC) scale and tibial acceleration data was recorded using a triaxial accelerometer system (KiRA). The difference in the tibial acceleration range between injured and contralateral limbs was used in the analysis. Correlation coefficients were calculated using linear regression. Multivariate logistic regression was used to identify risk factors for high grade pivot shift.

RESULTS

The clinical grade of pivot shift and the side-to-side difference in delta tibial acceleration determined by KiRA were significantly correlated (r = 0.57; 95% CI 0.513-0.658, p < 0.0001). The only risk factor identified to have a significant association with high grade pivot shift was an antero-posterior side to side laxity difference > 6 mm (OR = 2.070; 95% CI (1.259-3.405), p = 0.0042).

CONCLUSION

Side-to-side difference in tibial acceleration range, as measured by KiRA, is correlated with the IKDC pivot shift grade in anaesthetized patients. Side-to-side A-P laxity difference greater than 6 mm is reported as a newly defined risk factor for high grade pivot shift in the ACL injured knee.

DIAGNOSTIC STUDY

Level II.

Treatment after anterior cruciate ligament injury: Panther Symposium ACL Treatment Consensus Group

Treatment strategies for anterior cruciate ligament (ACL) injuries continue to evolve. Evidence supporting best practice guidelines for the management of ACL injury is to a large extent based on studies with low-level evidence. An international consensus group of experts was convened to collaboratively advance toward consensus opinions regarding the best available evidence on operative vs. non-operative treatment for ACL injury. The purpose of this study is to report the consensus statements on operative vs. non-operative treatment of ACL injuries developed at the ACL Consensus Meeting Panther Symposium 2019. Sixty-six international experts on the management of ACL injuries, representing 18 countries, were convened and participated in a process based on the Delphi method of achieving consensus. Proposed consensus statements were drafted by the Scientific Organizing Committee and Session Chairs for the three working groups. Panel participants reviewed preliminary statements prior to the meeting and provided the initial agreement and comments on the statement via an online survey. During the meeting, discussion and debate occurred for each statement, after which a final vote was then held. Eighty percent agreement was defined a-priori as consensus. A total of 11 of 13 statements on operative v. non-operative treatment of ACL injury reached the consensus during the Symposium. Nine statements achieved unanimous support, two reached strong consensus, one did not achieve consensus, and one was removed due to redundancy in the information provided. In highly active patients engaged in jumping, cutting, and pivoting sports, early anatomic ACL reconstruction is recommended due to the high risk of secondary meniscus and cartilage injuries with delayed surgery, although a period of progressive rehabilitation to resolve impairments and improve neuromuscular function is recommended. For patients who seek to return to straight plane activities, non-operative treatment with structured, progressive rehabilitation is an acceptable treatment option. However, with persistent functional instability, or when episodes of giving way occur, anatomic ACL reconstruction is indicated. The consensus statements derived from international leaders in the field will assist clinicians in deciding between operative and non-operative treatments with patients after an ACL injury.Level of evidence V.

Diagnosis and treatment of rotatory knee instability

BACKGROUND

Rotatory knee instability is an abnormal, complex three-dimensional motion that can involve pathology of the anteromedial, anterolateral, posteromedial, and posterolateral ligaments, bony alignment, and menisci. To understand the abnormal joint kinematics in rotatory knee instability, a review of the anatomical structures and their graded role in maintaining rotational stability, the importance of concomitant pathologies, as well as the different components of the knee rotation motion will be presented.

MAIN BODY

The most common instability pattern, anterolateral rotatory knee instability in an anterior cruciate ligament (ACL)-deficient patient, will be discussed in detail. Although intra-articular ACL reconstruction is the gold standard treatment for ACL injury in physically active patients, in some cases current techniques may fail to restore native knee rotatory stability. The wide range of diagnostic options for rotatory knee instability including manual testing, different imaging modalities, static and dynamic measurement, and navigation is outlined. As numerous techniques of extra-articular tenodesis procedures have been described, performed in conjunction with ACL reconstruction, to restore anterolateral knee rotatory stability, a few of these techniques will be described in detail, and discuss the literature concerning their outcome.

CONCLUSION

In summary, the essence of reducing anterolateral rotatory knee instability begins and ends with a well-done, anatomic ACL reconstruction, which may be performed with consideration of extra-articular tenodesis in a select group of patients.