Correlation between quantitative pivot shift and generalized joint laxity: a prospective multicenter study of ACL ruptures

Generalised joint hypermobility leads to increased odds of sustaining a second ACL injury within 12 months of return to sport after ACL reconstruction

OBJECTIVES

To determine the 12-month risk of a second anterior cruciate ligament (ACL) injury in a population of patients with and without generalised joint hypermobility (GJH) who return to sports (RTS) at competition level after ACL reconstruction (ACL-R).

METHODS

Data were extracted from a rehabilitation-specific registry for 16-50-year-old patients treated with ACL-R between 2014 and 2019. Demographics, outcome data and the incidence of a second ACL injury within 12 months of RTS, defined as a new ipsilateral or contralateral ACL, were compared between patients with and without GJH. Univariable logistic regression and Cox proportional hazards regression were performed to determine the influence of GJH and time of RTS on the odds of a second ACL injury, and ACL-R survival without a second ACL injury after RTS.

RESULTS

A total of 153 patients, 50 (22.2%) with GJH and 175 (77.8%) without GJH, were included. Within 12 months of RTS, 7 (14.0%) patients with GJH and 5 (2.9%) without GJH had a second ACL injury (p=0.012). The odds of sustaining a second ipsilateral or contralateral ACL injury were 5.53 (95% CI 1.67 to 18.29) higher in patients with GJH compared with patients without GJH (p=0.014). The lifetime HR of a second ACL injury after RTS was 4.24 (95% CI 2.05 to 8.80; p=0.0001) in patients with GJH. No between-group differences were observed in patient-reported outcome measures.

CONCLUSION

Patients with GJH undergoing ACL-R have over five times greater odds of sustaining a second ACL injury after RTS. The importance of joint laxity assessment should be emphasised in patients who aim to return to high-intensity sports following ACL-R.

Does Generalized Joint Laxity Affect Postoperative Alignment and Clinical Outcomes Following Medial Opening-Wedge High Tibial Osteotomy?

BACKGROUND

The purpose of this study was to investigate whether generalized joint laxity affects the postoperative alignment and clinical outcomes of medial opening-wedge high tibial osteotomy (MOWHTO).

METHODS

A total of 198 patients who underwent MOWHTO was divided into two groups according to absence or presence of generalized joint laxity. Generalized joint laxity was measured using the Beighton and Horan criteria, and a score of 4 or more out of 9 was defined as generalized joint laxity. A weight bearing line (WBL) ratio of 55% to 70% was considered an acceptable postoperative lower limb alignment range; WBL over 70% was defined as overcorrection and less than 55% as undercorrection. The WBL ratio was investigated before and 2 years after surgery, and the Western Ontario McMaster University Osteoarthritis Index scale score (WOMAC) was evaluated for patient-reported outcomes (PRO) of MOWHTO. There were 147 (73.7%) patients in the nongeneralized joint laxity group and 51 (26.3%) in the generalized joint laxity group. Preoperatively, there was no difference between the two groups in hip-knee-ankle (HKA) angle or WBL ratio (all P > .05).

RESULTS

At 2 years postoperatively, the generalized joint laxity group showed significantly higher HKA angle and WBL ratio than the nongeneralized joint laxity group (all P < .05). There was a significant difference in the distribution ratio of undercorrection, normocorrection, and overcorrection patients between the two groups (P < .05). There were no differences between the two groups in preoperative and postoperative WOMAC scores (all, P > .05).

CONCLUSION

The generalized joint laxity significantly affected postoperative over correction of alignment following MOWHTO. However, there was no significant difference in PRO between the patients who did and did not have generalized joint laxity after MOWHTO until 2 years.

Generalized joint hypermobility subjects without knee hyperextension have greater walking anterior tibial translation and flexion angle than those with knee hyperextension

BACKGROUND

The walking knee kinematic results of generalized joint hypermobility (GJH) subjects were controversial in previous studies. We proposed that this could be related to the knee statuses of GJH subjects with/without knee hyperextension (KH) and assumed that there are significant sagittal knee kinematic differences between GJH subjects with/without KH during gait.

RESEARCH QUESTION

Do GJH subjects with KH exhibit significantly different kinematic characteristics than those without KH during walking?

METHODS

35 GJH subjects without KH, 34 GJH subjects with KH, and 30 healthy controls were recruited in this study. A three-dimensional gait analysis system was used to record and compare the knee kinematics of the participants.

RESULTS

Significant walking knee kinematics differences were found between GJH subjects with/without KH during walking. GJH subjects without KH had greater flexion angles (4.7-6.0°, 24-53 % gait cycle (GC), p < 0.001; 5.1-6.1°, 65-77 % GC, p = 0.008) and anterior tibial translation (ATT) (3.3-4.1 mm, 0-4 % GC, p = 0.015; 3.8-4.3 mm, 91-100 % GC, p = 0.01) than those with KH. Compared to controls, GJH without KH exhibited increased ATT (4.0-5.7 mm, 0-26 % GC, p < 0.001; 5.1-6.7 mm, 78-100 % GC, p < 0.001), and range of motion of ATT (3.3 mm, p = 0.028) whereas GJH with KH only exhibited increased extension angle (6.9-7.3°, 62-66 % GC, p = 0.015) during walking.

SIGNIFICANCE

The findings confirmed the hypothesis and suggested that GJH subjects without KH had more walking ATT and flexion angle asymmetries than those with KH. This may raise concerns about the differences in knee health and risk of knee diseases between GJH subjects with/without KH. However, further investigations should be done to explore the exact influence of walking ATT and flexion angle asymmetries in GJH subjects without KH.

A comparison of the outcomes of anterior curciate ligament reconstruction with large-size graft versus reconstruction with average-size graft combined with extraarticular tenodesis

INTRODUCTION

Many patients who have had anterior cruciate ligament (ACL) reconstruction (R) complain of instability, inability to return to previous levels of sports activity, and possible ACL graft failure. Graft size was discovered to be an important factor in lowering ACL failure rates. Also, extraarticular tenodesis decreases recurrent instability, A comparative study was done to compare the effect of graft size and lateral external tenodesis on the recurrence of instability after ACL-R.

PATIENTS AND METHODS

A Prospective Blinded Randomized Controlled study included 100 consecutive patients who underwent ACL-R with hamstring tendon grafts in our Hospital. The patients were allocated into two groups (Group A and B) with randomization; group A received ACL-R with a large-size ACL-graft diameter of 6 strands, and group B received ACL-R of 4 strands combined with lateral extraarticular tenodesis (LET) (Modified Lemaire). Each group had fifty patients. The follow-up time was two years. They were examined for graft failure, anterolateral rotatory instability with the pivot shift test, and clinical outcomes, which were evaluated with the International Knee Documentation Committee score (IKDC) both subjective and objective.

RESULTS

In this study; group A, graft failure occurred in three (6.3%) patients, a positive pivot shift test grade I was detected in eight (17.8%) patients, grade II in three (6.7%) patients, and grade III in one (2.2%) patient. The subjective IKDC score was 87.9 (± 7.19) points. The objective IKDC score was normal or nearly normal in 43 (93.4%) patients. In group B, one (2.1%) patient had graft failure, five (10.9%) had a positive pivot shift test grade I, one (2.1%) had a grade II, and no patient had a grade III. The subjective IKDC score was 91.9 (± 8.9) points. The objective IKDC score was normal or nearly normal in 44 (95.6%) patients. As regard the subjective IKDC score, there was a non-significant difference between both groups (p value = 0.465).

CONCLUSION

Both groups showed a low ACL-graft failure rate, low anterolateral rotatory instability, and a good clinical outcome. Although there was no significant difference in subjective IKDC score between both groups, the failure rate and anterolateral rotatory instability were significantly lower in the ACL-R (4 strands) with LET combination group than in the group with the large-diameter (6 strands) graft.

LEVEL OF EVIDENCE

Level 1; Randomized Comparative Study.

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.

Anterior tibial subluxation measured under a modified protocol is positively correlated with posterior tibial slope: a comparative study of MRI measurement methods

PURPOSE

Anatomic factors, such as posterior tibial slope (PTS) and anterior tibial subluxation (ATS) obtained by quantitative measurement, have been proposed as predictors for clinical outcomes of anterior cruciate ligament (ACL) reconstruction. However, the correlation between PTS and ATS is controversial, and the method for quantitative ATS measurement remains unsettled. This study aimed to identify the correlation between PTS and ATS in patients with injured and intact ACLs and compare the two ATS measuring protocols.

METHODS

This study included 128 ACL-injured and 176 ACL-intact patients with no concomitant ligament injuries. PTS and ATS were measured on sagittal MRI. ATS was measured using two measuring protocols, including the modified protocol using the longitudinal tibial axis (axis protocol) and the established protocol using a line perpendicular to the tibial plateau (plateau protocol). Correlation analyses between PTS and ATS and between PTS and the difference in the ATS value measured under the two protocols (ATS_diff) were performed. The difference between the two ATS measuring protocols was further analyzed by trigonometric analysis. Intra- and interobserver reliability tests were performed for the axis protocol.

RESULTS

Under the axis protocol, ATS was positively correlated with PTS in both the ACL-injured and ACL-intact groups (p < 0.001). Under the plateau protocol, no correlation was observed in the ACL-injured group. In the ACL-intact group, no correlation was observed for lateral ATS, and a negative correlation was observed for medial ATS (p = 0.001). ATS_diff was positively correlated with PTS (p < 0.001), indicating that the two protocols varied greatly in those with a steep PTS. Trigonometric analysis showed that a steep PTS influenced the measurement of ATS under the plateau protocol but not the axis protocol. Intra- and interobserver reliability tests showed good-to-excellent strength of reliability for the ATS measurement under the axis protocol.

CONCLUSION

ATS measured under the axis protocol was positively correlated with PTS, indicating that a steep PTS was associated with a worse anatomic tibiofemoral relationship. The axis protocol for ATS measurement is a promising method for clinical use since it is not influenced by PTS and reflects the global position of the tibia.

LEVEL OF EVIDENCE

III.

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.

The Ratio of Stress to Nonstress Anterior Talofibular Ligament Length on Ultrasonography: Normative Values

Background:

Stress ultrasonography (US) has been shown to be a valid procedure for evaluating chronic anterior talofibular ligament (ATFL) injury. The ratio of stress/nonstress ATFL length (ATFL ratio) as measured on US is clinically useful; however, there are no published normative data concerning this ratio.

Purpose:

To report a normative value of the ATFL ratio on US and evaluate the relationships between sex, generalized joint laxity (GJL), and the grade of anterior drawer test (ADT).

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

The ATFL lengths were prospectively measured in the stress and nonstress positions (manual maximal anterior drawer position) for participants with noninjured ankles from March 2020 to March 2021. GJL was defined as a Beighton score ≥4. A manual ADT was also performed. The ATFL ratio was calculated, and the relationships between sex, GJL, and ADT grade were evaluated.

Results:

A total of 333 ankles in 184 participants (mean age, 24.5 ± 2.7 years; range, 20-33 years) were eligible for the analysis. GJL was found in 69 ankles (20.7%). The mean ATFL ratio was 1.08 ± 0.04 (95% CI, 1.08-1.09; range, 1.01-1.24), and there was a significant difference between male (1.07 ± 0.04; 95% CI, 1.07-1.08; range, 1.02-1.23) and female (1.09 ± 0.04; 95% CI, 1.08-1.10; range, 1.01-1.24) ankles (P = .001). In male ankles, the ATFL ratio was significantly greater in participants with GJL (1.11 ± 0.06 vs 1.07 ± 0.03; P = .02) or a higher grade of ADT (grade 2 vs grade 1: 1.11 ± 0.06 vs 1.07 ± 0.03, P = .002). These findings were not observed in female ankles.

Conclusion:

The normative value of the ATFL ratio on stress US was 1.07 ± 0.04 in men and 1.09 ± 0.04 in women. The ATFL ratio was affected by the presence of GJL in men but not in women. These findings will be useful for future studies seeking to establish the cutoff value of the ATFL ratio for diagnosing chronic lateral ankle stability on stress US.

Association Between Meniscal Allograft Tears and Early Surgical Meniscal Allograft Failure

BACKGROUND

Meniscal allograft transplantation (MAT) has become a viable treatment option for patients with symptomatic meniscal deficiency. Some patients experience early surgical meniscal allograft failure attributed to causes that have not yet been sufficiently clarified.

PURPOSE

To evaluate the prevalence, types, and distribution of arthroscopically confirmed meniscal allograft tears and the associated effect on surgical meniscal allograft survival.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients undergoing MAT with a minimum 2-year follow-up were retrospectively reviewed. Descriptive and surgical data were collected. Type and location of arthroscopically confirmed meniscal allograft tears were recorded and compared between medial and lateral allografts and suture-only and bone block fixation. A survival analysis was conducted to evaluate the effect of meniscal allograft tears on surgical meniscal allograft survival.

RESULTS

This study included 142 patients (54% male; mean ± SD age, 29.6 ± 10.4 years) with a mean follow-up of 10.3 ± 7.5 years. The prevalence of meniscal allograft tears was 32%, observed at a median of 1.2 years (interquartile range, 2.8 years) after MAT. The posterior horns were most frequently affected, followed by the posterior roots, midbodies, anterior horns, and anterior roots. The most frequently observed tear types were root tears (43%), followed by longitudinal, horizontal, radial, complex, bucket-handle, and meniscocapsular separation tears. A statistically significant association was found between meniscal allograft tear types and fixation techniques (P = .027), with root tears predominant after suture-only as compared with bone block fixation (57% vs 22%). Patients with meniscal allograft root tears were a mean of 5.4 years (95% CI, 1.6-9.2 years; P = .007) younger than were patients without root tears. The 1-year surgical meniscal allograft survival rate was significantly lower for torn versus intact meniscal allografts (75% vs 99%; P < .001).

CONCLUSION

Meniscal allograft root tears were predominant, associated with younger patient age, and more often observed when using the suture-only fixation technique versus the bone block fixation technique. Torn meniscal allografts were associated with early surgical graft failure when compared with intact meniscal allografts, resulting in a significantly lower 1-year survival rate.

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.

Prevalence and dynamic characteristics of generalized joint hypermobility in college students

BACKGROUND

Generalized joint hypermobility (GJH) is a common, but often ignored, condition characterized by general joint laxity, which is reported to increase one's risk of anterior cruciate ligament (ACL) injury and osteoarthritis. Nevertheless, it is not clearly learned in the prevalence and dynamic characteristics in college students.

RESEARCH QUESTION

Is the active motion stability in the six-degree-of-freedom (6DOF) kinematics of the knee joint of people with GJH poorer than that of others?

METHODS

This is a cross-sectional study. A population of 489 college students was recruited who was divided into two groups: a GJH group (Beighton score ≥ 4, n = 54) and a normal group (Beighton score < 4, n = 435). A paper questionnaire with questions about the participants' demographic characteristics and musculoskeletal disorder symptoms was collected. A three-dimensional gait analysis system was used to collect the participants' knee joint kinematic parameters during treadmill walking. Variables were evaluated using independent t-tests and Wilcoxon signed-rank tests.

RESULTS

The prevalence of GJH was found to be 11.0 % among college students. Participants with GJH exhibited a greater active range of motions in the anterior/posterior translation than the normal (P =  0.026). Participants with GJH exhibited greater flexion at the end of the terminal stance (P = 0.039) and greater anterior translation of the tibia during almost the whole gait period than the normal group (P＜0.05) during the treadmill gait. A greater external angle was found in GJH group during the periods of middle stance (P = 0.008).

SIGNIFICANCE

GJH with a prevalence of 11.0 % among college students should be paid attention. Poor active motion stability in anterior/posterior translation may play an important role in the development of knee joint instability, potentially resulting in subsequent ACL deficiency and the development of knee osteoarthritis among people with GJH.

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.

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.

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.

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.

Patients With Failed Anterior Cruciate Ligament Reconstruction Have an Increased Posterior Lateral Tibial Plateau Slope: A Case-Controlled Study

PURPOSE

To compare knee anatomical parameters of patients with failed anterior cruciate ligament reconstruction (ACL-R) with those of a control group of sex-matched patients with successful ACL-R.

METHODS

Forty-three patients (34 male, 9 female) who experienced graft failure after ACL-R were enrolled in the failed group. These patients were matched to a control group of 43 patients who underwent primary ACL-R with a minimum follow-up of 24 months. On magnetic resonance imaging, the following parameters were evaluated: transepicondylar distance, lateral and medial femoral condyle widths, tibial plateau width, notch width index, and the ratio of width and height of the femoral notch, ratio between the height and depth of the lateral and medial femoral condyle, lateral and medial posterior tibial slopes, and anterior subluxation of the lateral and medial tibial plateau. Multivariate regression with backward elimination, including only the previously identified significant variables, defined the independent predictors for revision surgery.

RESULTS

The anatomical variables that were significantly different between the 2 study groups were lateral and medial posterior tibial slopes, anterior subluxation of the lateral and medial tibial plateau, medial tibial plateau width, lateral tibial plateau width, medial femoral condyle width, and transepicondylar distance; however, the multivariate regression analysis identified the lateral posterior tibial slope (LTPs), the anterior subluxation of the medial tibial plateau, and the medial femoral condyle width as significant independent predictors (P < .05). The LPTs had the highest coefficient and the highest sensitivity (88%) and specificity (84%) to identify failures when considering the optimal cutoff value of 7.4°.

CONCLUSIONS

Several anatomical parameters have been identified that differ significantly between patients with failed ACL-R and those without a documented failure. The most accurate predictor of ACL failure was an LTPs >7.4°, with a sensitivity of 88% and specificity of 84%. Surgeons should consider measuring LTPs during preoperative assessment of ACL-injured patients, and patients with values >7.4° should be considered at high risk of ACL-R failure.

LEVEL OF EVIDENCE

Level III retrospective prognostic trial.

Static Lateral Tibial Plateau Subluxation Predicts High-Grade Rotatory Knee Laxity in Anterior Cruciate Ligament-Deficient Knees

BACKGROUND

In anterior cruciate ligament-deficient (ACL-D) knees, injury pattern and bony morphologic features have been shown to influence both static anterior tibial subluxation relative to the femur and dynamic rotatory knee laxity. Therefore, the relationship between static anterior tibial subluxation and dynamic rotatory knee laxity was investigated.

PURPOSE

To determine whether static tibial subluxation as measured on magnetic resonance imaging (MRI) is associated with the grade of rotatory knee laxity in ACL-D knees.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Two-hundred fifty-eight knees underwent preoperative, image-guided assessment of lateral knee compartment translation during quantitative pivot shift (QPS). Subluxations of the medial and lateral tibial plateaus were measured on preoperative MRI in a subset of primary ACL-D knees meeting criteria for high-grade (QPS > 5.2 mm) and low-grade (QPS < 2.4 mm) rotatory laxity. Tibial subluxations on MRI were compared between patients with high- and low-grade rotatory laxity through use of pairwise t test and were analyzed via univariate and multivariate logistic regression. Significance was set at P < .05.

RESULTS

On MRI, greater anterior subluxation of the lateral tibial plateau was observed in patients with high-grade compared with low-grade rotatory knee laxity (4.5 mm vs 2.3 mm; P < .05). No similar relationship was observed for the medial tibial plateau (-0.9 mm vs -0.4 mm; P > .05). Univariate logistic regression demonstrated that static subluxation of the lateral tibial plateau was associated with high-grade rotatory knee laxity (odds ratio [OR], 1.2; P < .05). An optimal cutoff of 2.95 mm of static lateral tibial subluxation was associated with high-grade rotatory knee laxity (sensitivity, 75%; specificity, 63%). Lateral meniscal injury was the first variable entered into a multivariate regression analysis and proved to be most associated with high-grade rotatory knee laxity (OR, 6.8; P < .05). When lateral meniscal injury was excluded from multivariate regression analysis, static anterior subluxation of the lateral tibial plateau alone was associated with high-grade rotatory knee laxity (OR, 1.2; P < .05).

CONCLUSION

Data from this MRI study of two distinct rotatory knee laxity groups showed that static anterior subluxation of the lateral tibial plateau of 2.95 mm or greater was associated with high-grade rotatory knee laxity, and each millimeter increase of lateral tibial plateau subluxation was associated with a 1.2-fold odds of high-grade rotatory knee laxity. Anterior subluxation of the lateral tibial plateau on MRI was not independently associated with high-grade rotatory knee laxity in the presence of concomitant lateral meniscal injury. Static measurements made preoperatively may aid in predicting high-grade rotatory knee laxity and refining the indications for individualized knee surgery.

Preoperative laxity in ACL-deficient knees increases with posterior tibial slope and medial meniscal tears

PURPOSE

The aim of this study was to determine patient and anatomic factors that influence anteroposterior and rotational laxity in knees with ACL tears. Based on the findings of biomechanical studies, we hypothesized that static and dynamic anterior tibial translation (ATT) as well as positive pivot shift would increase with female gender, tibial slope, and meniscal tears.

METHODS

The authors prospectively collected preoperative data and intraoperative findings of 417 patients that underwent ACL reconstruction. The exclusion criteria were: revision ACL procedures (n = 53), other surgical antecedents (n = 27), prior osteotomies (n = 7) or concomitant ligament tears on the ipsilateral knee (n = 34), and history of ACL tears in the contralateral knee (n = 45), leaving a study cohort of 251 patients. Their preoperative anteroposterior knee laxity was assessed objectively using 'static' monopodal weight-bearing radiographs and 'dynamic' instrumented differential measurements of ATT. Rotational laxity was assessed subjectively using the pivot shift test.

RESULTS

Multivariable regression showed that static ATT increases only with tibial slope (β = 0.30; p < 0.001), but dynamic ATT increases with tibial slope (β = 0.19; p = 0.041), medial meniscal tears (β = 1.27; p = 0.007), complete ACL tears (β = 2.06; p < 0.001), and to decrease with age (β = - 0.09; p < 0.001). Multivariable regression also indicated that high-grade pivot shift decreases with age (OR 0.94; p < 0.001) and for women (OR 0.25; p < 0.001), and to be higher for knees with complete ACL tears (OR 3.04; p = 0.002) or medial meniscal tears (OR 2.28; p = 0.010).

CONCLUSION

Contrary to expectations based on biomechanical studies, static ATT was only affected by high posterior tibial slope, while dynamic ATT was affected by both high posterior tibial slopes and medial meniscal tears, but not by gender or lateral meniscal tears. Likewise, pivot shift was affected by gender and medial meniscal tears, but not lateral meniscal tears or posterior tibial slope. These findings are relevant to guide surgeons in optimizing their surgical procedures, such as conserving the menisci when possible, and rehabilitation protocols, by delaying full weight-bearing and return to sports in patients with anatomic and lesional risk factors.

LEVEL OF EVIDENCE

Cohort study, Level IV.

The Pivot Shift: Current Experimental Methodology and Clinical Utility for Anterior Cruciate Ligament Rupture and Associated Injury

PURPOSE OF REVIEW

The purpose of this manuscript is to (1) examine the history, techniques, and methodology behind quantitative pivot shift investigations to date and (2) review the current status of pivot shift research for its clinical utility for management of anterior cruciate ligament (ACL) rupture with associated injuries including the anterolateral complex (ALC).

RECENT FINDINGS

The pivot shift is a useful physical exam maneuver for diagnosis of rotatory instability related to ACL tear. Recent evidence suggests that the pivot shift is multifactorial and can be seen in the presence of ACL tear with concomitant injury to secondary stabilizers or with predisposing anatomical factors. The presence of a pivot shift post-operatively is associated with poorer outcomes after ACL reconstruction. Recent clinical and biomechanical investigations can help guide clinicians in utilizing pivot shift in diagnosis and surgical planning. Further research is needed to clarify optimal management of ALC in addition to ACL injury.

Contralateral knee hyperextension is associated with increased anterior tibial translation and fewer meniscal injuries in the anterior cruciate ligament-injured knee

PURPOSE

To investigate the influence of hyperextension of the contralateral healthy knee on anterior tibial translation (ATT) and the presence of associated injuries in the anterior cruciate ligament (ACL)-injured knee.

METHODS

A local patient data register containing the surgical and clinical data of patients undergoing ACL reconstruction was analyzed. Patients were divided into groups according to the degree of hyperextension of the contralateral knee: normal (Group A ≤ 0°), mild (Group B 1°-5°), moderate (Group C 6°-10°), and severe (Group D > 10°). The ATT was measured in both knees preoperatively and 6 months postoperatively using the KT-1000 arthrometer. The presence of associated meniscal and cartilage injuries was noted. Using multivariate analysis, Groups B, C, and D were compared with Group A, using this group as a reference.

RESULTS

A total of 10,957 patients were available in the register and 8502 (Group A n = 4335, Group B n = 3331, Group C n = 771, Group D n = 65) were included in the final analysis. Groups B (10.3 mm; 95% CI 0.06-0.042, p < 0.0001) and C (10.6 mm; 95% CI 0.23-0.89, p = 0.006) showed significantly greater preoperative ATT in the injured knee compared with the control group (10.1 mm). Moreover, at the 6-month follow-up, greater ATT was observed for Groups B (8.5 mm; 95% CI 0.13-0.45, p < 0.0001), C (8.5 mm; 95% CI 0.02-0.60, p = 0.035), and D (9.1 mm; 95% CI - 0.08-1.77, p = 0.082) compared with Group A (8.2 mm). Meniscal injuries were less frequent in patients with contralateral hyperextension [Group B 903 (27.1%) p < 0.0001, Group C 208 (27.0%) p = 0.0003, and Group D 12 (18.5%), 0.012] compared with the control group [Group A 1479 (34.1%)].

CONCLUSION

Contralateral knee hyperextension is associated with greater pre- and postoperative ATT in the ACL-injured knee. In patients with contralateral knee hyperextension, concomitant injuries to the menisci are less frequent. Surgeons should consider grafts with superior properties regarding postoperative anteroposterior laxity to patients with contralateral knee hyperextension.

LEVEL OF EVIDENCE

Retrospective cohort study, Level IV.