Pivot Shift Research Articles

Severe bicompartmental bone bruise is associated with rotatory instability in anterior cruciate ligament injury

PurposeThe presence and severity of bone bruise is more and more investigated in the non-contact anterior cruciate ligament (ACL) injury context. Recent studies have advocated a correlation between bone bruise and preoperative knee laxity. The aim of the present study was to investigate the correlation between bone bruise and preoperative rotatory knee laxity.MethodsTwenty-nine patients (29.1 ± 9.8 years) with MRI images at a maximum of 3 months after ACL injury (1.6 ± 0.8 months) were included. The bone bruise severity was evaluated according to the International Cartilage Repair Society (ICRS) scale for lateral femoral condyle, lateral tibial plateau, medial femoral condyle, and medial tibial plateau. The intraoperative rotational knee laxity was evaluated through a surgical navigation system in terms of internal–external rotation at 30° and 90° of knee flexion (IE30, IE90) and internal–external rotation and acceleration during pivot-shift test (PS IE, PS ACC). The KOOS score was also collected. The association between ICRS grade of bone bruise and rotational laxity or KOOS was investigated.ResultsSignificant correlation (p < 0.05) was found between the bone bruise severity on the medial tibial plateau and rotational laxity (IE90, PS IE, and PS ACC) and between the severity of bone bruise on femoral lateral condyle and KOOS-Symptoms sub-score. The presence of bone bruise on the medial tibial plateau was significantly associated with a lateral femoral notch sign > 2 mm (very strong odds ratio). No kinematical differences were found between none-to-deep and extensive-generalized lateral bone bruise, while higher IE30 and IE90 were found in extensive-generalized bicompartmental bone bruise than isolated extensive-generalized lateral bone bruise.ConclusionA severe bicompartmental bone bruise was related to higher rotatory instability in the intraoperative evaluation of ACL deficient knees. The severity of edema on the medial tibial plateau was directly correlated with higher intraoperative pivot shift, and the size of edema on the lateral femoral condyle was associated with lower preoperative clinical scores.Level of evidenceLevel II.

ACL Repair of Femoral Osseous Avulsion in a 13-Year-Old Using Suture Pullout Technique

Background: The incidence of pediatric anterior cruciate ligament (ACL) injuries has been increasing over the past 20 years, with the majority comprised of mid substance tears or tibial eminence avulsion fractures. Pediatric femoral sided osseous avulsion is rarely reported in orthopedic literature and specific surgical indications and contraindications, as well as recommended surgical techniques and postoperative rehabilitation protocols, are underdefined. Indications: The surgical indications for femoral-sided repair of ACL osseous avulsion includes a displaced osseous fragment and ligamentous laxity on physical examination. There was no concomitant midsubstance tear necessitating reconstruction. Technique Description: Two sutures piercing the proximal ligamentous bony junction of the ACL were fed through 2.4-mm transphyseal tunnels and secured with cortical button and backup fixation with a 3.9-mm swivel lock anchor in the proximal lateral femoral metaphysis. The patient was immobilized in a hinged-knee brace locked in extension during ambulation and limited to 90 degrees of flexion while nonweightbearing for the first 6 weeks after surgery. Standard ACL protocol was followed thereafter. Results: Successful fixation and restoration of ligamentous tension and impingement-free range of motion were achieved without complication. There was stable Lachman, negative pivot shift, 125 degrees of knee flexion, and evidence of early healing at 3 months follow-up. Discussion/Conclusion: This report demonstrates successful reduction and fixation of proximal bony avulsion of the ACL. Although this patient exhibits stable physical examination and undisturbed growth at early follow-up, more research is required to establish treatment and rehabilitation guidelines for this rare injury.

Bone-patellar tendon-bone autograft maturation is superior to double-bundle hamstring tendon autograft maturation following anatomical anterior cruciate ligament reconstruction.

The primary purpose of this study was to evaluate the second-look arthroscopic findings 1year postoperatively and magnetic resonance imaging (MRI) findings 2years after anterior cruciate ligament reconstruction (ACLR) using bone-patellar tendon-bone autograft (BTB) or hamstring tendon autograft (HT). Secondary purpose included clinical results from physical examination, including range of motion, Lachman test, pivot shift test, and knee anterior laxity evaluation, and the clinical score for subjective evaluations at 2years after surgery. Between 2015 and 2018, 75 patients with primary ACL injuries were divided into either the BTB group (n = 30) or HT group (n = 45). When using HT, an anatomical double-bundle ACLR was performed. BTB was indicated for athletes with sufficient motivation to return to sporting activity. Graft maturation on second-look arthroscopy was scored in terms of synovial coverage and revascularization. All participants underwent postoperative MRI evaluation 2years postoperatively. The signal intensity (SI) characteristics of the reconstructed graft were evaluated using oblique axial proton density-weighted MR imaging (PDWI) perpendicular to the grafts. The signal/noise quotient (SNQ) was calculated to quantitatively determine the normalized SI. For clinical evaluation, the Lachman test, pivot shift test, KT-2000 evaluation, Lysholm score, and Knee injury and Osteoarthritis Outcome Score (KOOS) were used. Arthroscopic findings showed that the graft maturation score in the BTB group (3.6 ± 0.7) was significantly greater than that in the anteromedial bundle (AMB; 2.9 ± 0.2, p = 0.02) and posterolateral bundle (PLB; 2.0 ± 0.9, p = 0.001) in the HT group. The mean MRI-SNQs were as follows: BTB, 2.3 ± 0.5; AMB, 2.9 ± 0.9; and PLB, 4.1 ± 1.1. There were significant differences between BTB, AMB, and PLB (BTB and AMB: p = 0.04, BTB and PLB: p = 0.003, AMB and PLB: p = 0.03). Second-look arthroscopic maturation score and MRI-SNQ value significantly correlated for BTB, AMB, and PLB. No significant differences were detected in clinical scores. There was a significant difference (p = 0.02) in the knee laxity evaluation (BTB: 0.9 ± 1.1mm; HT: 2.0 ± 1.9mm). BTB maturation is superior to that of double-bundle HT based on morphological and MRI evaluations following anatomical ACLR, although no significant differences were found in clinical scores. Regarding clinical relevance, the advantages of BTB may help clinicians decide on using the autograft option for athletes with higher motivation to return to sporting activity because significant differences were observed in morphological evaluation, MRI assessment, and knee anterior laxity evaluation between BTB and double-bundle HT. Level IV.

Clinical outcome of anterior cruciate ligament reconstruction with modified transtibial and anteromedial portal

Arthroscopic ACL reconstruction is the current standard care of treatment for anterior cruciate ligament (ACL) injuries. Modified transtibial (mTT) and anteromedial portal (AMP) techniques aim at the anatomical placement of femoral tunnel. Controversy existed in the literature with regard to the outcome of these techniques. Hence, we designed a retrospective comparative study to analyse the clinical and functional outcomes of mTT and AMP techniques. We hypothesized that there would be no difference between the clinical and functional outcomes in mTT and AMP techniques. This retrospective observational study was conducted in consecutive patients who underwent arthroscopic ACL reconstruction using semitendinosus-gracilis (STG) quadrupled graft in our tertiary care centre with a minimum follow-up of two years. Out of 69 patients, 37 had undergone ACL reconstruction by mTT technique and remaining by AMP technique. All the patients were assessed clinically by anterior drawer, Lachman’s, pivot shift and single-legged hop test. Lysholm Knee Scoring Scale and International Knee Documentation Committee (IKDC) subjective knee evaluation score were used for the functional status. Knee instability was assessed objectively by KT-1000 arthrometer. There was no statistically significant difference in baseline demographic characteristics between mTT and AMP groups. At the end of 2 years, no statistically significant difference was noted in the anterior drawer and Lachman’s test. Though not significant, IKDC scores and Lysholm’s scores showed a better outcome in the AMP group when compared to the mTT group. AMP group showed significantly better outcome with KT-1000 arthrometer. Based on the results obtained, we presume that overall both mTT and AMP have similar functional outcome. However, as AMP technique offers significantly improved subjective rotational stability on pivot shift test, better hop limb symmetry index and KT 1000 readings compared to mTT, we suggest AMP over mTT.

MRI findings of acute anterior instability of the knee in the absence of recent trauma

Anterior knee instability is usually encountered in the context of trauma, with the clinical examination and imaging focusing on anterior cruciate ligament (ACL) disruption. Limited data exist on magnetic resonance imaging (MRI) of acute anterior knee instability in the absence of recent trauma. To provide the first comprehensive account of MRI findings in acute anterior knee laxity in the absence of acute trauma and to evaluate predictors of ACL integrity and pain. A total of 84 consecutive patients with non-traumatic knee instability were prospectively studied. Instability was assessed with Lachman's, pivot shift, and Lelli's tests. MRI findings were recorded, and ACL integrity was surgically confirmed in all 24 cases of MRI suggesting tear and in 21/60 cases of MRI suggesting no tear. Binary logistic regression models were used to identify predictors of ACL tears and pain, and Mann-Whitney U test served for comparisons between continuous variables. The study was approved by the institutional review board. Osteoarthritis and notch bony outgrowth (NBO) were present in 44% and 42.9% of all knees, respectively. NBO did not correlate with osteoarthritis (P = 0.606). NBO (odds ratio [OR] = 4.157; P = 0.016) and ACL grafts (OR = 9.277; P = 0.01) predisposed to non-traumatic ACL tears (torn in 28.6% of total cases). Presence of osteoarthritis was predictive of pain (OR = 17.671; P < 0.001). We present a comprehensive analysis of MRI findings in clinically significant non-traumatic anterior instability, showing that NBO and ACL grafts predispose in non-traumatic ACL tears, whereas osteoarthritis is the only predictor of pain.

English

Knee injuries are common in sports and depending on the mechanism of fall, injury of different ligaments can occur. Knee injury mostly involves the anterior cruciate ligament (ACL), and is the most common injury reported on MRI. It can be associated with posterolateral corner (PLC) injury and other osseous injuries, these injuries are rarely reported as they are very complex in structure. A detail knowledge about this complex helps to evaluate the associated ligaments as well. In association with anterior cruciate ligament injuries presence of a Segond fracture indicates occurrence of a concomitant or isolated injury to the posterolateral corner injury. The evaluation of these associated injuries along with anterior cruciate ligament aids in their repair and hence improving the postoperative outcome. Three main components of posterolateral corner are divided into three layers – superficial, middle, and deep. Clinically few tests have been advised to evaluate injury of different structures of knee joint. For example - McMurray's test and Ege's test are used to evaluate meniscus, Lachman test, Anterior drawer test and Pivot Shift Test are performed to evaluate anterior cruciate ligament tear while posterior drawer test is done to evaluate posterior cruciate ligament tear. Availability of special closely coupled extremity coils, high field systems, open system &amp; extremity units have made MRI supplemental to clinical examination and plain radiographs for virtually all suspected disorders of knee. Here, we are presenting a case of MRI of knee injury involving posterolateral corner injury with anterior cruciate ligament tear and Segond fracture. Along with anterior cruciate ligament, medial meniscus, other ligaments and osseous injury are associated as well. The other structures responsible for stabilizing the knee joints are posterolateral corner and meniscus, which when involved may need to be treated simultaneously with anterior cruciate ligament tear, for full re stabilization of knee joint. If any associated fracture is present, it has to be treated simultaneously as well.

A Surgical Algorithm According to Pivot-Shift Grade in Patients With ACL Injury: A Prospective Clinical and Radiological Evaluation

Background:Some patients have a positive pivot-shift finding and rotational instability after anterior cruciate ligament (ACL) reconstruction (ACLR). Three major pathologies known to affect the pivot-shift examination include ACL tear, anterolateral ligament injury, and loss of posterior lateral meniscus root function.Purpose:To describe a surgical algorithm determining indications for lateral extra-articular tenodesis (LET) based on intraoperative pivot-shift examination to prevent postoperative pivot shift and rotational instability and to evaluate the 2-year clinical and functional outcomes.Study Design:Case series; Level of evidence, 4.Methods:The study included 47 consecutive patients (39 men and 8 women) who underwent operative treatment for ACL injury between 2016 and 2017. Pivot-shift examination was performed under anesthesia, and the pivot shift was graded as grade 1 (glide), grade 2 (clunk), or grade 3 (gross). According to the surgical algorithm, single-bundle ACLR was performed in patients with grade 1 pivot shift. In patients with grade 2 with loss of posterior lateral meniscus root function, concurrent lateral meniscal repair was performed, and in patients with grade 2 with an intact lateral meniscus posterior root, concurrent extra-articular iliotibial band tenodesis was performed. Patients with grade 3 underwent ACLR, lateral meniscal repair, and LET. Clinical and radiographic evaluations were performed.Results:The mean age was 27.2 years (range, 16-56 years). In total, 26 (55.3%) patients were evaluated as having pivot-shift grade 1; 16 (34%) patients, grade 2; and 5 (10.6%) patients, grade 3. A total of 7 (14.9%) patients underwent LET in addition to ACLR. Two of these patients had pivot-shift grade 2, and LET was performed since the lateral meniscus posterior root was intact. In 14 of 16 patients with grade 2, lateral meniscus root disruption was detected, and lateral meniscal repair was performed. One patient was excluded from the further follow-up because of graft failure. At a mean postoperative follow-up of 29 months in 46 patients, the pivot-shift examination was negative in all patients. The mean Lysholm and International Knee Documentation Committee subjective scores were 95.35 ± 4.40 and 82.87 ± 9.36, respectively. Radiographic evidence of osteoarthritis was not detected.Conclusion:Only 14.9% of patients needed LET. With proper ACL, lateral meniscal, and anterolateral ligament surgery, it was possible to prevent positive pivot-shift findings postoperatively.

Augmentation of Primary ACL Reconstruction With a Modified Ellison Lateral Extra-articular Tenodesis in High-Risk Patients: A Pilot Study.

Background:Lateral extra-articular tenodesis (LET) has been used to augment primary anterior cruciate ligament (ACL) reconstruction to reduce the risk of reinjury. Most LET procedures result in a construct that is fixed to both the femur and the tibia. In a modified Ellison procedure, the construct is only fixed distally, reducing the risk of inadvertently overconstraining the lateral compartment.Purpose:To evaluate the use of the modified Ellison procedure in a cohort of patients deemed to be at a high risk of further ACL injury after primary ACL reconstruction.Study Design:Case series; Level of evidence, 4.Methods:Included were 25 consecutive patients with at least 2 of the following risk factors: age <20 years at the time of surgery, previous contralateral ACL reconstruction, positive family history of ACL rupture (parent or sibling), generalized ligamentous laxity (Beighton ≥4), grade 3 pivot shift in the consulting room, a desire to return to a pivoting sport, and an elite or professional status. All patients underwent primary ACL reconstruction with an additional modified Ellison procedure. Postoperatively, patients completed the IKDC subjective knee evaluation form (International Knee Documentation Committee), KOOS Quality of Life subscale (Knee injury and Osteoarthritis Outcome Score), ACL–Return to Sport After Injury Scale, Marx Activity Rating Scale, and SANE score (Single Assessment Numeric Evaluation).Results:At 12-month follow-up, the mean outcome scores were as follows: SANE, 94/100; IKDC, 92/100; Marx, 13/16; ACL–Return to Sport, 85/100; and KOOS, 77/100. At 24 months, return-to-sport data were available for 23 of 25 patients; 17 (74%) were playing at the same level or higher than preinjury and 2 at a lower level. One patient (4%) sustained a contact mechanism graft rupture at 12 months. There were 2 (9%) contralateral ACL injuries, including 1 ACL graft rupture, at 11 and 22 months postoperatively. There was a further contralateral ACL graft rupture at 26 months.Conclusion:The use of the modified Ellison procedure as a LET augmentation of a primary ACL reconstruction to produce a low graft rupture rate appeared to be safe in a cohort considered to be at a high risk of reinjury. The procedure showed promise in terms of reducing further graft injuries.

Lateral Extra-articular Tenodesis Alters Lateral Compartment Contact Mechanics under Simulated Pivoting Maneuvers: An In Vitro Study

Background: There is concern that utilization of lateral extra-articular tenodesis (LET) in conjunction with anterior cruciate ligament (ACL) reconstruction (ACLR) may disturb lateral compartment contact mechanics and contribute to joint degeneration. Hypothesis: ACLR augmented with LET will alter lateral compartment contact mechanics in response to simulated pivoting maneuvers. Study Design: Controlled laboratory study. Methods: Loads simulating a pivot shift were applied to 7 cadaveric knees (4 male; mean age, 39 ± 12 years; range, 28-54 years) using a robotic manipulator. Each knee was tested with the ACL intact, sectioned, reconstructed (via patellar tendon autograft), and, finally, after augmenting ACLR with LET (using a modified Lemaire technique) in the presence of a sectioned anterolateral ligament and Kaplan fibers. Lateral compartment contact mechanics were measured using a contact stress transducer. Outcome measures were anteroposterior location of the center of contact stress (CCS), contact force from anterior to posterior, and peak and mean contact stress. Results: On average, augmenting ACLR with LET shifted the lateral compartment CCS anteriorly compared with the intact knee and compared with ACLR in isolation by a maximum of 5.4 ± 2.3 mm (P < .001) and 6.0 ± 2.6 mm (P < .001), respectively. ACLR augmented with LET also increased contact force anteriorly on the lateral tibial plateau compared with the intact knee and compared with isolated ACLR by a maximum of 12 ± 6 N (P = .001) and 17 ± 10 N (P = .002), respectively. Compared with ACLR in isolation, ACLR augmented with LET increased peak and mean lateral compartment contact stress by 0.7 ± 0.5 MPa (P = .005) and by 0.17 ± 0.12 (P = .006), respectively, at 15° of flexion. Conclusion: Under simulated pivoting loads, adding LET to ACLR anteriorized the CCS on the lateral tibial plateau, thereby increasing contact force anteriorly. Compared with ACLR in isolation, ACLR augmented with LET increased peak and mean lateral compartment contact stress at 15° of flexion. Clinical Relevance: The clinical and biological effect of increased anterior loading of the lateral compartment after LET merits further investigation. The ability of LET to anteriorize contact stress on the lateral compartment may be useful in knees with passive anterior subluxation of the lateral tibia.

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

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. 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 ≤ 6months) and chronic injuries (> 6months). 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. 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 III.

Anterolateral ligament reconstruction in addition to primary double-bundle anterior cruciate ligament reconstruction for grade 3 pivot shift improves residual knee instability during surgery

PurposeHigh-grade pivot shift in the anterior cruciate ligament (ACL) injured knee is a risk factor for postoperative residual pivot shift. Procedures in addition to ACL reconstruction such as anterolateral ligament (ALL) reconstruction have been performed for patients with a high-risk of residual pivot shift. The aim of this study was to investigate the effect of the addition of ALL reconstruction to primary double-bundle ACL reconstruction in patients with preoperative high-grade pivot shift to improve stability as evaluated by quantitative measurement.MethodsPatients with ACL injuries who showed preoperative grade 3 subjective pivot shift and who underwent primary double-bundle ACL reconstruction combined with ALL reconstructions were retrospectively enrolled. Anterior tibial translation (ATT) in the Lachman test, and acceleration and external rotational angular velocity (ERAV) in the pivot shift were measured as quantitative values. Quantitative values before surgical intervention for ACL-injured knees (ACLD) and uninjured contralateral knees (intact), after temporary fixation of the isolated ACL grafts (ACLR), and subsequently after temporary fixation of both ACL and ALL grafts (ACLR + ALLR) were measured with the patient under general anaesthesia.ResultsIn total, 18 patients were included. The ATT was lower in ACLR and ACLR + ALLR than in intact (P = .008 and .005), while there was no significant difference between ACLR and ACLR + ALLR (P > .05). The acceleration of ACLR + ALLR was lower than that for ACLR (P = .008), while there was no significant difference between intact and ACLR or ACLR + ALLR (P > .05). The ERAV of ACLR was higher than that of intact (P < .001), while that of ACLR + ALLR was lower than that of ACLR (P < 0.001), and there was no significant difference in ERAV between intact and ACLR + ALLR (P > 0.05).ConclusionAccording to quantitative assessment of the pivot shift, the addition of ALL reconstruction to primary double-bundle ACL reconstruction improved residual knee instability and restored knee stability during surgery. Combination of ALL reconstruction with primary double-bundle ACL reconstruction was effective for patients with ACL injuries exhibiting a preoperative grade 3 subjective pivot shift.Level of evidenceIV

Neither Residual Anterior Knee Laxity Up to 6 mm nor a Pivot Glide Predict Patient-Reported Outcome Scores or Subsequent Knee Surgery Between 2 and 6 Years After ACL Reconstruction

Background: A primary goal of anterior cruciate ligament reconstruction (ACLR) is to reduce pathologically increased anterior and rotational laxity of the knee, but the effects of residual laxity on patient-reported outcomes (PROs) after ACLR remain unclear. Hypothesis: Increased residual laxity at 2 years postoperatively is predictive of a higher risk of subsequent ipsilateral knee surgery and decreases in PRO scores from 2 to 6 years after surgery. Study Design: Cohort study; Level of evidence, 2. Methods: From a prospective multicenter cohort, 433 patients aged <36 years were identified at a minimum 2 years after primary ACLR. These patients underwent a KT-1000 arthrometer assessment and pivot-shift test and completed PRO assessments with the Knee injury and Osteoarthritis Outcome Score and International Knee Documentation Committee (IKDC) scores. Patients completed the same PROs at 6 years postoperatively, and any subsequent ipsilateral knee procedures during this period were recorded. Subsequent surgery risk and change in PROs from 2 to 6 years postoperatively were compared based on residual side-to-side KT-1000 arthrometer differences (<−1 mm, −1 to 2 mm, 2 to 6 mm, and >6 mm) in laxity at 2 years postoperatively. Multiple linear regression models were built to determine the relationship between 2-year postoperative knee laxity and 2- to 6-year change in PROs while controlling for age, sex, body mass index, smoking status, meniscal and cartilage status, and graft type. Results: A total of 381 patients (87.9%) were available for follow-up 6 years postoperatively. There were no significant differences in risk of subsequent knee surgery based on residual knee laxity. Patients with a difference >6 mm in side-to-side anterior laxity at 2 years postoperatively were noted to have a larger decrease in PROs from 2 to 6 years postoperatively (P < .05). No significant differences in any PROs were noted among patients with a difference <6 mm in side-to-side anterior laxity or those with pivot glide (IKDC B) versus no pivot shift (IKDC A). Conclusion: The presence of a residual side-to-side KT-1000 arthrometer difference <6 mm or pivot glide at 2 years after ACLR is not associated with an increased risk of subsequent ipsilateral knee surgery or decreased PROs up to 6 years after ACLR. Conversely, patients exhibiting a difference >6 mm in side-to-side anterior laxity were noted to have significantly decreased PROs at 6 years after ACLR.

Increased Rotatory Laxity after Anterolateral Ligament Lesion in Anterior Cruciate Ligament- (ACL-) Deficient Knees: A Cadaveric Study with Noninvasive Inertial Sensors.

The anterolateral ligament (ALL) has been suggested as an important secondary knee restrain on the dynamic laxity in anterior cruciate ligament- (ACL-) deficient knees. Nevertheless, its kinematical contribution to the pivot-shift (PS) phenomenon has not been clearly and objectively defined, and noninvasive sensor technology could give a crucial contribution in this direction. The aim of the present study was to quantify in vitro the PS phenomenon in order to investigate the differences between an ACL-deficient knee and an ACL+ALL-deficient knee. Ten fresh-frozen paired human cadaveric knees (n = 20) were included in this controlled laboratory study. Intact, ACL-deficient, and ACL+ALL-deficient knees were subjected to a manual PS test quantified by a noninvasive triaxial accelerometer (KiRA, OrthoKey). Kinematic data (i.e., posterior acceleration of the tibial lateral compartment) were recorded and compared among the three statuses. Pairwise Student's t-test was used to compare the single groups (p < 0.05). Intact knees, ACL-deficient knees, and ACL+ALL-deficient knees showed an acceleration of 5.3 ± 2.1 m/s2, 6.3 ± 2.3 m/s2, and 7.8 ± 2.1 m/s2, respectively. Combined sectioning of ACL and ALL resulted in a statistically significant acceleration increase compared to both the intact state (p < 0.01) and the ACL-deficient state (p < 0.01). The acceleration increase determined by isolated ACL resection compared to the intact state was not statistically significant (p > 0.05). The ALL sectioning increased the rotatory laxity during the PS after ACL sectioning as measured through a user-friendly, noninvasive triaxial accelerometer.

Effect of native ligament versus graft reconstruction on sensitivity of clinical tests used to diagnose anterior cruciate ligament tears

PurposeAlthough there have been multiple clinical studies evaluating the accuracy of physical examination tests used to diagnose anterior cruciate ligament (ACL) injury, there are no data to date evaluating the accuracy of these tests in diagnosing re-injury after prior ACL reconstruction. We compared the sensitivity of three clinical tests — Lachman, anterior drawer, and pivot shift — in diagnosing initial ACL tears versus graft re-tears following a prior ACL reconstruction. MethodsTwenty consecutive adult patients who had undergone primary ACL reconstruction and 20 consecutive adult patients who had undergone revision ACL reconstruction by a single surgeon at a tertiary care center from November 2011 to December 2017 were included in this study. ResultsThe sensitivity of the Lachman test was 95.0% in diagnosing ACL tears in patients with native ACL versus 85.0% in patients with prior ACL reconstruction with allograft or autograft. The sensitivity of the anterior drawer test was 80.0% in patients with native ACL compared to 77.8% in patients with prior ACL reconstructions. The sensitivity of the pivot shift test could not be accurately assessed because pain and swelling prevented the physician from performing this test in most patients on their initial presentation to the clinic. ConclusionsThis study suggests that a clinician may need to have a lower threshold to perform advanced imaging or diagnostic arthroscopic evaluation in a patient with prior ACL reconstruction with a suspected re-injury even if the physical examination tests are not immediately positive.

TIBIAL PHYSEAL RESPECTING TUNNEL DRILLING TECHNIQUE FOR ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION IN SKELETALLY IMMATURE ATHLETES

Background:ACL reconstruction is common in young patients.Hypothesis/Purpose:To report outcomes of a novel tibial drilling technique using an inside-out socket drilling method, with a drill pin and epiphyseal socket drilling in skeletally immature patients. Minimizing disruption to the tibial physis, attempting to prevent growth disturbance with an anatomic ACL that eliminates the graft bend angle at the tibial tunnel.Methods:We used a standard all-epiphyseal drilling technique for femoral preparation. The tibial drill guide, set at 55° for our tibial physeal respecting approach, is positioned in the posterior third of the ACL footprint in-line with the posterior aspect of the lateral meniscus anterior root. The FlipCutter (Arthrex Inc., Naples, FL) is drilled from the external proximal tibia. Thus, only a 3.5mm diameter tunnel crosses the proximal tibial physis. With the FlipCutter deployed, the cutting radius is checked to confirm proper position without risk of damage to the meniscal root, PCL, or articular cartilage. With fluoroscopic guidance, the tibial socket is drilled from the intra-articular surface towards the physis, stopping proximal to the physis. This results in a 15 to 20 mm all-epiphyseal socket length. We collected demographics, re-tear rate, physeal arrest (partial/complete), and patient reported outcomes in order to understand potential problems and mid-term outcomes of this procedure.Results:Eight male patients were included in the study (average age=10.6±1.5 years). All patients had radiographs >6months post-surgery, and no patient had a clinically significant leg length discrepancy (>2cm) or deformity. The two patients followed >24months post-operatively were cleared to return to sports by one year. No patients demonstrated a positive Lachman or pivot shift test at >6months follow-up. No Patients had a ROM deficit at >6months follow-up. Five patients completed Pedi-IKDC and Lysholm assessments (time from surgery=16.2months+10.6months; range 7–28.8months). Average IKDC and Lysholm scores were 88+10 and 95+9, respectively. There were no graft ruptures in the cohort (average follow-up: 13.8months±8.9 months; range 6.8–30.6months).Conclusion:Our preliminary data from this novel tibial physeal respecting technique suggest it may be appropriate for skeletally immature patients with sufficiently large enough femoral epiphyses to hold a 10mm graft tunnel without disturbance to the physis. This technique seems successful in terms of graft survival, patient reported outcomes, and no growth disturbance within 2 years of surgery, although we recognize our small sample size as a limitation. Further studies will better evaluate long-term outcomes of this pediatric ACLR technique.

Functional outcome in arthroscopic anterior cruciate ligament reconstruction by suspensory fixation in comparison with aperture fixation method

Background: Arthroscopic anterior cruciate ligament (ACL) reconstruction with suspensory and aperture fixation methods has been proposed to recreate the natural anatomy of ACL. Reconstruction of the anatomy of the ACL has been thought to be able to restore the rotational stability of the knee joint. Nevertheless, it remains unclear whether the suspensory fixation method has a better functional outcome than the aperture fixation method.Aim: To assess the clinical outcome of Arthroscopic ACL Reconstruction using suspensory fixation and aperture fixation methods. Methods: We prospectively followed 40 patients with an isolated ACL injury operated for ACL reconstruction after applying the inclusion and exclusion criteria. Patients were evaluated pre-operatively and in the post-operative period at regular intervals with the minimum follow up of 6 months. Functional outcome was evaluated by the Modified Lysholm knee score. Clinical stability was assessed by Lachman, anterior drawer, and pivot shift tests. Results: Functional outcome in terms of Lysholm score was satisfactory at the end of six months with both suspensory and aperture fixation methods. Graded stability results of the Lachman, anterior drawer and pivot shift tests were almost near to that in the normal knee with both the methods. Conclusion: ACL reconstruction by suspensory and aperture fixation methods seem to offer satisfactory results in terms of subjective scores and stability tests in patients with ACL tears, with no particular clinical advantage of one method over the other.

Dynamic Radiostereometry Evaluation of 2 Different Anterior Cruciate Ligament Reconstruction Techniques During a Single-Leg Squat.

Background:Lateral extra-articular tenodesis in the context of anterior cruciate ligament (ACL) reconstruction (ACLR) is performed to better control anterolateral knee instability in patients with high-grade preoperative pivot shift. However, some authors believe these procedures may cause lateral compartment overconstraint, affecting knee motion in daily life.Purpose/Hypothesis:The primary aim of the present study was to identify kinematic differences during the execution of an activity under weightbearing conditions between knees having undergone ACLR using anatomic single-bundle (SB) versus single-bundle plus lateral plasty (SBLP) techniques. The secondary aim was to compare the postoperative kinematic data with those from the same knees before ACLR and from the healthy contralateral knees in order to investigate if ACLR was able to restore physiologic knee biomechanics during squat execution. The hypotheses were that (1) the SBLP technique would allow a better restoration of internal-external (IE) knee rotation than would SB and (2) regardless of the technique, ACLR would not fully restore physiologic knee biomechanics.Study Design:Randomized controlled trial; Level of evidence, 2.Methods:In total, 32 patients (42 knees) were included in the study. Patients were asked to perform a single-leg squat before surgery (ACL-injured group, n = 32; healthy contralateral group, n = 10) and at minimum 18-month follow-up after ACLR (SB group, n = 9; SBLP group, n = 18). Knee motion was determined using a validated model-based tracking process that matched patient-specific magnetic resonance imaging bone models to dynamic biplane radiographic images under the principles of roentgen stereophotogrammetric analysis. Data processing was performed using specific software. The authors compared IE and varus-valgus rotations and anterior-posterior and medial-lateral translations among the groups.Results:The mean follow-up period was 21.7 ± 4.5 months. No kinematic differences were found between the SB and SBLP groups (P > .05). A more medial tibial position (P < .05) of the ACL-injured group was reported during the entire motor task and persisted after ACLR in both the SB and the SBLP groups. Differences in IE and varus-valgus rotations were found between the ACL-injured and healthy groups.Conclusion:There were no relevant kinematic differences between SBLP and anatomic SB ACLR during the execution of a single-leg squat. Regardless of the surgical technique, ACLR failed in restoring knee biomechanics.Registration:NCT02323386 (ClinicalTrials.gov identifier).

A New Arthroscopic Tightrope Suture-Button Fixation Procedure for Tibial Eminence Avulsion Fracture.

This case-series outcome study presents a new arthroscopic technique for tibial eminence avulsion fracture (TEAF) with double-tunnel using two tightrope suture buttons. From May 2017 to July 2020, we performed a new arthroscopic technique for TEAF with double tunnels, using two tightrope suture buttons on 13 patients. Clinical assessments included anterior drawer, Lachman, and pivot shift tests, the International Knee Documentation Committee (IKDC), Lysholm knee scores, visual analog scale (VAS) scores, and range of motion (ROM). An independent observer noted conditions before surgery and during the last follow-up. The patients had an average follow-up of 26.2 months, ranging from 15 to 37 months. During the last postsurgical follow-up, the anterior drawer, Lachman, and pivot shift tests were negative in all the cases. According to the IKDC, Lysholm, and VAS final scores, all patients presented a significant knee function improvement at last follow-ups compared with preoperatively. The study shows that satisfactory results about an anatomic reduction of the fragment, knee stability, function, and strength can be achieved with the new arthroscopic technique for TEAF with double tunnels using two tightrope suture buttons. This study is a therapeutic case series and its level of evidence is IV.

Functional result of anterior cruciate ligament reconstruction by remnant preservation in a tertiary center in Eastern India

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; Anterior cruciate ligament (ACL) reconstruction is one of the most common procedures in orthopaedics. Orthopaedic surgery is vastly evolving to give better functional outcome. Apart from stability, proprioception, ligament healing are important factors for return to sports. The presence of remnant containing mechanoreceptors and free neural endings can help reinnervate the ACL auto graft. Aims and objectives were to evaluate clinical outcomes in patients undergoing ACL reconstruction with remnant preservation.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods&lt;/strong&gt;: One hundred and six patients who underwent ACL reconstruction between April 2014 and March 2020. Among these 80 patients underwent remnant preservation. Analysis is done based on international knee documentation committee score (IKDC), modified Cincinnati knee rating system (MCKRS) and Tegner-Lysholm scoring system. Other factors are Lachman test, pivot shift test, return to sports and graft rupture rate.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results:&lt;/strong&gt; Lachman test became negative in 98% at 12 weeks and in all the patients at 24 months post-operatively. 74 patients (92.5%) among 80 patients develop full range of knee movement after ACL surgery. Post-operative scores are 95, 93, and 92 respectively.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;Remnant preserving ACL reconstruction having excellent clinical outcome with good knee stability, early return to sports activities and no incidence of graft rupture in our series.&lt;/p&gt;

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 5o 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.