Complete Anterior Cruciate Ligament Injury Research Articles

Early degenerative changes are different between partial and complete anterior cruciate ligament injury and associate with joint instability in a skeletally immature porcine model

ObjectiveAnterior cruciate ligament (ACL) injuries are a major problem in the pediatric and adolescent populations. Some of these injuries are only partial; yet, there is limited data to inform clinical treatment of such partial tears. It is unknown how injury partial injury impacts long-term degenerative changes in the joint relative to complete injury. In this study, we hypothesized that partial (anteromedial (AM) or posterolateral (PL) bundle) tears would result in small levels of instability and degeneration relative to complete ACL tears and that the degree of degeneration would associate with joint instability. DesignPartial (isolated AM or PL bundle) or complete ACL injury was arthroscopically created in 3-month-old juvenile pigs. The contralateral limb served as a sham-operated control. Six months after injury, joint biomechanics was assessed along with cartilage and meniscus degeneration (via MRI, gross imaging, and histology). ResultsJoint laxity increases were minimal after PL bundle injury (difference relative to controls (confidence interval): 0.5 (-1.2-2.2) mm), minor after AM bundle injury (3.7 (2.0-5.4) mm), and major after ACL injury (15.8 (13.7-17.8) mm). Cartilage MRI T1ρ relaxation times increased minimally after PL bundle injury (-0.9 (-5.1-3.3) ms for lateral tibia), moderately after AM bundle injury (6.6 (1.7-11.4) ms), and substantially after ACL injury (10.8 (2.1-19.5) ms). Changes in meniscus volume followed a similar rank order. Degeneration was associated with the extent of joint destabilization. ConclusionsThese findings suggest that cartilage and meniscus degeneration in the skeletally immature joint are associated with joint laxity after partial and complete ACL injuries.

Arthroscopic-Assisted Fixation of Tibial Spine Fractures

Tibial spine fractures (TSF) are an avulsion injury of the anterior cruciate ligament (ACL) at the insertion on the tibial plateau. These injuries predominantly affect the pediatric population and are important to treat appropriately as they act similarly to complete ACL injuries. The decision to pursue surgical management is dictated mostly by fracture displacement, but also by various factors such as concomitant injuries, age and level of activity. Multiple fixation strategies are available, ranging from transosseous suture and suture anchors to the use of screws, staples or absorbable nails.This technique paper describes the author's preferred technique involving an arthroscopic assisted reduction of the tibial spine fracture and transosseous suture fixation. High tensile non-absorbable sutures are passed through the base of the ACL which are then passed through two 2.4mm transosseous tunnels tied over a bone bridge on the anterior medial tibia.An arthroscopic approach has been reported to have similar positive outcomes when compared to open reductions. Furthermore, the transosseous suture construct has been described to be advantageous biomechanically and to yield satisfactory results when compared to alternative fixation options.

The infrapatellar fat pad contributes to spontaneous healing after complete anterior cruciate ligament injury.

Anterior cruciate ligament (ACL) injuries have a very low healing capacity but have recently been shown to heal spontaneously with conservative treatment. This study examined the mechanism of spontaneous ACL healing by focusing on the intra-articular tissues of the knee joint. Skeletally mature Wistar rats (n = 70) were randomly assigned to two groups: the controlled abnormal movement (CAM) and anterior cruciate ligament transection (ACLT) groups. The ACL was completely transected at the mid-portion in both groups. Only the CAM group underwent extra-articular braking to control for abnormal tibial translation. The animals were allowed full cage activity until sacrifice for histological, and molecular biology analyses. The results showed that the behavior of the stump after ACL injury differed between models 12 h after injury. The femoral stump in the ACLT group retreated posteriorly and upwardly. Macrophage polarity analysis revealed that the stump immune response in the CAM group was more activated than that in the ACLT group 6 h after injury. Microarray analysis of the ACL parenchyma and infrapatellar fat pads suggested the involvement of nuclear factor kappa B (NF-κB) signaling. Real-time polymerase chain reaction (PCR) analysis showed that NF-κB gene expression in the infrapatellar fat pad was significantly increased in the CAM group than in the ACLT group. However, there was no difference in the gene expression levels in the ACL parenchyma between models. In conclusion, the healing response of the ACL was activated within 12 h of injury, resulting in differences in the healing response between the models. It has been suggested that infrapatellar fat pads are involved in the healing process and that angiogenesis and antiapoptotic effects through NF-κB signaling may contribute to this mechanism.

Treatment of Sports Injuries in Orthopedic Surgery: Recent Advances

This article reviews the most recent advances in the literature regarding orthopedic surgery for sports injuries. For large-to-massive rotator cuff tears, non-surgical treatment yielded superior results at three months to surgical treatment, although surgical treatment provided better results over time. Arthroscopic partial repair without a posterior interval slide yielded superior results to complete arthroscopic rotator cuff repair with a posterior interval slide. Graft bridging yielded superior results to superior capsular reconstruction. In first-time shoulder dislocations, arthroscopic Bankart repair has yielded superior results to arthroscopic washout. In high-grade acromioclavicular separation, a single clavicle tunnel tendon graft construct is preferable to a double tunnel construct. In femoroacetabular impingement, patients treated with hip arthroscopy had superior short-term results to those treated with physiotherapy alone. The odds of needing anterior cruciate ligament (ACL) graft revision were 2.1-fold higher for patients using a hamstring autograft than those using a patellar bone-tendon-bone (BTB) autograft. The use of a patellar tendon graft reduced the risk of graft rupture. The return-to-sports rate was higher for patients who underwent surgery with a BTB autograft than those with an autograft hamstring. The combination of lateral extra-articular tenodesis and ACL reconstruction-ACLR (single-bundle hamstring autograft) decreased the risk of ACLR failure after two years of follow-up. In complete mid-substance ACL injuries, the bridge-enhanced ACL repair technique resulted in similar outcomes to autograft ACLR. Fresh-frozen allografts have been a good alternative to autografts in ACLR. In posterior medial meniscal root tears, root repair was associated with less arthritic progression than non-surgical treatment and partial meniscectomy. Medial patellofemoral ligament (MPFL) reconstruction has provided better results than MPFL repair in patellofemoral instability.

Reliability and assessment of partial or complete anterior cruciate ligament injuries with diagnostic arthroscopy

Background: Partial tears of anterior cruciate ligament (ACL) were more commonly identified in young group with knee twisting. Partial tears are characterized by tear involvement of less than 50% of the ligament is torn. The arthroscopic evaluation is considered as gold standard in diagnostic evaluation. The comparison of findings between partial and complete tears in magnetic resonance imaging (MRI) and arthroscopy helps in finding out reliability of diagnostic modalities and consider the surgeon to establish the plan of treatment. Methods: 2-year prospective study at the department of orthopedics, RRMCH, Bangalore, India. 40 consecutive patients with suspicion of cruciate injuries of knee were selected for the study from July 2018 to May 2021. The MR imaging of knee in selected cases were performed and the findings were obtained. The descriptive statistical analysis was prepared which includes spectrum of MRI findings in cruciate injuries of knee that were correlated with arthroscopy findings in determining the accuracy. Results: Total 40 patients, we obtained 100% sensitivity and 66.67% specificity, 93.75% accuracy of MRI with arthroscopy in diagnosing complete ACL tears. We obtained 90.91% sensitivity and 80% specificity, 87.50% accuracy of MRI with arthroscopy in diagnosing partial ACL tears. Conclusions: The partial tears can be missed or can be over diagnosed on MRI. These misinterpretations are more likely to happen due to intra-substance signal abnormality. Description of the status of ACL ligament in arthroscopy helped the orthopaedic surgeons in decision making as conservative approach in partial tears and reconstruction in a complete tear.

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

To investigate whether the high-grade pivot-shift phenomenon is associated with asymmetry of the lateral and medial compartment anterior tibial translation (L-ATT and M-ATT) and lateral meniscus posterior horn (LMPH) tears in anterior cruciate ligament (ACL) injuries. A retrospective analysis was performed on 192 consecutive patients who had complete ACL injuries between January 2019 and December 2020. Among these, 156 met the inclusion criteria. L-ATT and M-ATT were measured using preoperative weight-bearing magnetic resonance imaging (MRI), and the differences between L-ATT and M-ATT were calculated. Thirty-five patients who demonstrated excessive differences in L-ATT and M-ATT (> 6.0mm) were regarded as asymmetric (study group), and 36 patients with minimal or no differences in L-ATT and M-ATT (< 3.0mm) were allocated to the control group. Demographic data, grade of the pivot-shift test, integrality of LMPH, and medial meniscus posterior horn (MMPH) were compared between the groups. Moreover, predictors of high-grade pivot-shift phenomenon, including asymmetry of L-ATT and M-ATT, integrity of LMPH and MMPH, time from injury to surgery, sex, age, and body mass index (BMI) were assessed using multivariable logistic regression analysis. The difference between L-ATT and M-ATT in the study group was significantly higher than that in the control group (mean ± SD: 8.4 ± 2.1mm vs. 1.5 ± 1.0mm, P < 0.001). A higher proportion of patients with high-grade pivot-shift phenomenon (2 + and 3 +) and LMPH tears were identified in the study group (high-grade pivot-shift phenomenon: 25/35 vs. 13/36, P = 0.003; LMPH tears: 18/35 vs. 5/36, P = 0.001). Additionally, asymmetry of L-ATT, M-ATT (odds ratio 5.8; 95% CI 1.7-19.8; P = 0.005), and LMPH tears (odds ratio 3.8; 95% CI 1.3-11.6; P = 0.018) were found to be good predictors of the high-grade pivot-shift phenomenon after ACL injury, whereas MMPH tears, time from injury to surgery, sex, age, and BMI were not. In patients with ACL injury, the high-grade pivot-shift phenomenon is associated with asymmetry between L-ATT and M-ATT, and LMPH tears. III.

Age- and Sex-Specific Joint Biomechanics in Response to Partial and Complete Anterior Cruciate Ligament Injury in the Porcine Model.

Pediatric anterior cruciate ligament (ACL) injury rates are increasing and are highest in female adolescents. Complete ACL tears are typically surgically reconstructed, but few guidelines and very limited data exist regarding the need for surgical reconstruction or rehabilitation for partial ACL tears in skeletally immature patients. To evaluate the effects of partial (anteromedial bundle) and complete ACL transection on joint laxity and tissue forces under anterior and rotational loads in male and female stifle joints throughout skeletal growth in the porcine model. Descriptive laboratory study. Laboratory. We studied 60 male and female Yorkshire crossbreed pigs aged 1.5, 3, 4.5, 6, and 18 months (n = 6 pigs per age per sex). Joint laxity was measured in intact, anteromedial bundle-transected, and ACL-transected joints under applied anterior-posterior drawer and varus-valgus torque using a robotic testing system. Loading of the soft tissues in the stifle joint was measured under each condition. Anterior-posterior joint laxity increased by 13% to 50% (P < .05) after anteromedial bundle transection and 75% to 178% (P < .05) after ACL transection. Destabilization after anteromedial bundle transection increased with age (P < .05) and was greater in late female than late male adolescents (P < .05). In anteromedial bundle-transected joints, the posterolateral bundle resisted the anterior load. In ACL-transected joints, the medial collateral ligament (MCL) contribution was largest, followed by the medial meniscus. The MCL contribution was larger and the medial meniscus contribution was smaller in male versus female specimens. Partial ACL transection resulted in moderate increases in joint laxity, with the remaining bundle performing the primary ACL function. Destabilization due to partial ACL transection (anteromedial bundle) was largest in late adolescent joints, indicating that operative treatment should be considered in active, late-adolescent patients with this injury. Increased forces on the MCL and medial meniscus after ACL transection suggested that rehabilitation protocols may need to focus on protecting these tissues.

Magnetic resonance imaging does not reliably detect Kaplan fiber injury in the setting of anterior cruciate ligament tear.

There has been a continued effort to better understand the role Kaplan fiber injury plays in persistent instability following ACL tears. However, the prevalence of these injuries remains poorly understood. Therefore, the purpose of this study was to define the prevalence of Kaplan fiber injury in the setting of complete anterior cruciate ligament tear using a commonly used grading system for assessing ligament injuries. The inter-rater reliability of this commonly used grading system and the relationship between Kaplan fiber injury and injury to other structures commonly found in conjunction with ACL tears was also evaluated. All isolated, complete anterior cruciate ligament tears confirmed on magnetic resonance imaging within 90days of injury between 2014 and 2020 at a single institution were included for analysis. Each scan was read by two, fellowship-trained musculoskeletal radiologists. Kaplan fiber injury was evaluated using a previously described grading scheme. Kappa, [Formula: see text], of inter-rater agreement was determined for all magnetic resonance image scans. Kruskal Wallis test was performed to assess for associations between Kaplan fiber injury and magnet strength (1.5T vs. 3.0T), patient gender, the presence of medial and/or lateral meniscal tears, and/or posterolateral tibial bone bruise. Between 2014 and 2020, 131 patients (94 males, 37 females) with a complete anterior cruciate ligament tear were included in the final analysis. The mean age of the cohort was 27.8 ± 6.8years. Kaplan fiber injuries were identified in 51 of 131 (38.9%, CI 31.0-47.5%) scans with complete anterior cruciate ligament injuries (Grade 1: 28, Grade 2: 18, and Grade 3: 5). Inter-rater agreement for Kaplan fiber injury was fair ([Formula: see text] with 43 (32.8%) scans requiring third reviewer adjudication. There were no significant associations between Kaplan fiber injury and gender, magnet strength, meniscal tears, or posterolateral tibial bone bruise. The prevalence of Kaplan fiber injuries was comparable to previously described rates; however, the classification system used to report Kaplan fiber injury was associated with low inter-rater reliability. The presence of Kaplan fiber injury was not associated with other injuries commonly observed in conjunction with ACL tear. The previously proposed Kaplan fiber injury classification system is not reproducible nor is it likely to aid surgeons in distinguishing higher grades of rotatory knee instability. Level IV.

Correlation of Femoral Trochlear Dysplasia With Anterior Cruciate Ligament Injury in Skeletally Immature Patients

Background:Reports of anterior cruciate ligament (ACL) injury in patients with skeletal immaturity have been increasing. Variations in knee joint anatomy have been linked to ACL injury risk factors.Purpose:To identify associations between ACL injury, patella alta, and femoral trochlear dysplasia in patients with skeletal immaturity by using magnetic resonance imaging (MRI).Study Design:Cross-sectional study; Level of evidence, 3.Methods:This retrospective study included 231 patients with skeletal immaturity—116 with acute complete noncontact ACL injury and 115 without ACL injury (controls)—who underwent knee MRI. Cases of femoral trochlear dysplasia were divided into 4 types according to the Dejour classification scheme. Patellar height and patellar tendon length were measured via sagittal MRI, and the Insall-Salvati ratio (ISR) was calculated.Results:In the ACL injury group, 56 (48.3%) knees exhibited trochlear dysplasia, including 51 (91.1%) that were Dejour type A; and in the control group, 12 (10.4%) knees exhibited trochlear dysplasia, 12 (100%) Dejour type A. The prevalence of femoral trochlear dysplasia was significantly higher in the ACL injury group than in the control group (P < .001). The ISR was not significantly different between the ACL injury and control groups (0.9 ± 0.2 vs 1 ± 0.2 mm; P = .16). The correlation between ISR >1.2 and presence of ACL injury was not significant.Conclusion:Femoral trochlear dysplasia was associated with ACL injury in patients with skeletal immaturity. In particular, Dejour type A femoral trochlear dysplasia was correlated with ACL injury patients with skeletal immaturity. Also, the possibility of ACL damage exists in patients with skeletal immaturity and femoral trochlear dysplasia.

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.

Meniscal tears associated with complete vs partial anterior cruciate ligament injury

Purpose: To investigate the incidence and location of meniscal tears in relation to complete vs partial anterior cruciate ligament (ACL) injury.Subjects and Methods: We collected MRI of 114 patients (114 knees) diagnosed with combined ACL and meniscal injury at a follow up 3 months to 2 years of knee injury at our center in last 3 years. The subjects comprised 68 males and 46 females ranging in age from 20 to 55 years. The patients were divided into two groups: Meniscal tears with Partial ACL injury and Complete ACL injury and the results were compared between this two groups.Results: The incidence of complete ACL injury diagnosed with MRI was 52.63% (60 of 114 knees) and partial ACL injury was 47.36% (54 of 114 knees). Regarding the locations of meniscal tears, in complete ACL injury (60 knees), medial meniscal tear was found in 60% (36 of 60 knees), lateral meniscal tear in 31.66 % (19 of 60 knees), and bilateral meniscal tears in 8.33 % (5 of 60 knees). In Partial ACL injury (54 knees), medial meniscal tear was found in 46.29 % (25 of 54 knees) and lateral meniscal tear in 42.59 % (23 of 54 knees) and bilateral (including medial and lateral) meniscal tears in 11.11 % (6 of 54 knees). Bucket handle tear was observed in 11 knees (medial: 8 knees, lateral: 3 knees) in complete ACL injury, and 4 knees (medial: 3 knees, lateral: 1 knee) in partial ACL injury.Conclusion: Incidence of medial meniscus tear was more than 50% in complete ACL injury. Lateral meniscus tear was more associated with partial ACL injury compared to complete ACL injury.

Seeing Beyond Morphology-Standardized Stress MRI to Assess Human Knee Joint Instability.

While providing the reference imaging modality for joint pathologies, MRI is focused on morphology and static configurations, thereby not fully exploiting the modality’s diagnostic capabilities. This study aimed to assess the diagnostic value of stress MRI combining imaging and loading in differentiating partial versus complete anterior cruciate ligament (ACL)-injury. Ten human cadaveric knee joint specimens were subjected to serial imaging using a 3.0T MRI scanner and a custom-made pressure-controlled loading device. Emulating the anterior-drawer test, joints were imaged before and after arthroscopic partial and complete ACL transection in the unloaded and loaded configurations using morphologic sequences. Following manual segmentations and registration of anatomic landmarks, two 3D vectors were computed between anatomic landmarks and registered coordinates. Loading-induced changes were quantified as vector lengths, angles, and projections on the x-, y-, and z-axis, related to the intact unloaded configuration, and referenced to manual measurements. Vector lengths and projections significantly increased with loading and increasing ACL injury and indicated multidimensional changes. Manual measurements confirmed gradually increasing anterior tibial translation. Beyond imaging of ligament structure and functionality, stress MRI techniques can quantify joint stability to differentiate partial and complete ACL injury and, possibly, compare surgical procedures and monitor treatment outcomes.

Computer-Assisted System in Stress Radiography for Anterior Cruciate Ligament Injury with Correspondent Evaluation of Relevant Diagnostic Factors.

We sought to design a computer-assisted system measuring the anterior tibial translation in stress radiography, evaluate its diagnostic performance for an anterior cruciate ligament (ACL) tear, and assess factors affecting the diagnostic accuracy. Retrospective research for patients with both knee stress radiography and magnetic resonance imaging (MRI) at our institution was performed. A complete ACL rupture was confirmed on an MRI. The anterior tibial translations with four different methods were measured in 249 patients by the designed algorithm. The diagnostic accuracy of each method in patients with all successful measurements was evaluated. Univariate logistic regression analysis for factors affecting diagnostic accuracy of method four was performed. In the inclusive 249 patients, 177 patients (129 with completely torn ACLs) were available for analysis. Mean anterior tibial translations were significantly increased in the patients with a completely torn ACL by all four methods, with diagnostic accuracies ranging from 66.7% to 75.1%. The diagnostic accuracy of method four was negatively associated with the time interval between stress radiography and MRI as well as force-joint distance on stress view, and not significantly associated with age, gender, flexion angle, intercondylar distance, and force-joint angle. A computer-assisted system measuring the anterior tibial translation in stress radiography showed acceptable diagnostic performance of complete ACL injury. A shorter time interval between stress radiography and MRI as well as shorter force-joint distance were associated with higher diagnostic accuracy.

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

IntroductionEarly recognition of potential predictors on the success of conservative treatment of anterior cruciate ligament (ACL) is important, as appropriate treatment can be applied to each individual patient. The goal of this study is to assess the patient demographic and radiological parameters that predict coping with ACL injuries. MethodsAll patients presenting with a complete ACL injury between 2014 and 2018 at our clinic were included. The role of patient demographics (age, gender, activity level, meniscus injury and time from injury to clinic), and ACL tear location, bone bruises, tibial slope, and anterolateral ligament (ALL) injury were assessed on the success of conservative treatment using univariate and multivariate analyses. ResultsSixty-five patients (32%) were copers and 141 (68%) were non-copers. Univariate analysis showed that copers were significantly older (40 vs. 27 years, P < 0.001), had lower preinjury activity level (Tegner 5.7 vs. 6.5, P < 0.001) and less often lateral meniscus tears (16% vs. 5%, P = 0.019) but not medial meniscus tears (17% vs. 14%, P = 0.609) than non-copers. Multivariate analysis revealed that increasing age (P < 0.001), Tegner level ≤ 6 (P = 0.003) and no meniscus injury (P = 0.045) were independent predictors of coping with ACL deficiency. ConclusionsOlder age, participation in lower activity sports levels and absence of meniscus injury were predictive of coping with ACL deficiency, whereas there was no such role for tear location, tibial slope, lateral bone bruise presence, ALL injury or gender. These findings might help to identify potential copers and guide surgeons early in the optimal treatment for patients with ACL injury.

Anterior cruciate ligament injury patterns and their relationship to fatigue and physical fitness levels - a cross-sectional study.

Anterior cruciate ligament (ACL) injury is one of the most common knee injuries that leads to many consequences such as early osteoarthritis and knee joint instability.To explore the association of the types of ACL tear (complete and partial) and side of injury (dominant vs nondominate) with types of playing surfaces, sports, shoes, and mechanism of injuries as well as to determine whether higher levels of fatigue and physical fitness are risk factors for complete ACL tear.This cross-sectional study used a questionnaire to collect information from young male adults with a confirmed ACL injury who were attending rehabilitation programs. The outcomes of interest were patterns of ACL injury, levels of fatigue before the injury on a 0 to 10 scale, and levels of physical fitness (hours per week). Mann–Whitney U and Kruskal Wallis tests were used to assess the differences between groups, while the odds ratios were calculated to evaluate risk factors for complete ACL tear.One hundred thirteen young male adults with a confirmed ACL injury were enrolled. Most of the reported ACL injuries in this study were complete tear (80.5%) and occurred more frequently in the dominant leg (74.6%) due to noncontact mechanism (63.6%). More ACL injuries happened while playing soccer (97.2%) on artificial turf (53.3%). The level of fatigue before ACL injury was significantly higher in partial ACL tear injuries compared to complete ACL tear injuries (P = .014). For every 1-point increase in the level of fatigue on a 0–10 scale, there was a 25% reduction in complete ACL injury risk (P = .023).The pattern of ACL types of tear and side of injury varies in different playing surfaces and mechanisms of injuries. Higher levels of fatigue seem to be associated with a partial tear of the ACL and reduction of a complete ACL tear risk factor.

O’Donoghue Sports Injury Award: Bridge-Enhanced ACL Repair is Non-Inferior to Autograft ACL Reconstruction at 2-Years: Results of a Prospective Randomized Clinical Trial

Objectives:Preclinical studies and an early clinical cohort study have suggested that for complete midsubstance ACL injuries, the technique of suture repair of the anterior cruciate ligament (ACL) augmented with a protein implant placed in the gap between the torn ends (bridge-enhanced ACL repair) may be a viable alternative to ACL reconstruction. We hypothesized that patients treated with bridge-enhanced ACL repair would have non-inferior patient reported outcomes and anteroposterior (AP) laxity, and superior hamstring strength at 2 years after surgery when compared with subjects who had ACL reconstruction with autograft.Study Design:Prospective Randomized Control Trial (NCT02664545).Methods:One hundred patients, ages 13 to 35, with complete mid-substance ACL injuries, were enrolled and underwent surgery within 45 days of injury. Sixty-five patients were randomized to receive a bridge-enhanced ACL repair (BEAR group) and 35 were randomized to receive autograft ACL reconstruction (ACLR group). Outcomes, including the International Knee Documentation Committee (IKDC) Subjective score, instrumented AP laxity and muscle strength were assessed at 2 years post-operatively. Both patients and assessors were blinded as to surgical assignment until after the 2-year assessment.Results:Ninety-six percent of the subjects returned for follow-up at 2 years. The median age of the subjects in both groups at enrollment was 17 years and the median pre-operative Marx score in both groups was 16 points. Non-inferiority criteria were met for both the IKDC subjective score and AP laxity. The BEAR group had significantly better recovery of hamstring strength than the ACLR group (p<0.001). The number of subjects who were reinjured and required a second ACL surgery was not statistically different between the two groups. Subjects who converted from BEAR to ACLR in the study period had outcomes at the 2-year point that were similar to those for subjects who had only a single ipsiateral ACL procedure (BEAR or ACLR).Conclusion:Bridge-enhanced ACL repair using a specific protein-based implant led to non-inferior outcomes to that of ACL reconstruction for patient reported and instrumented knee laxity measures at 2 years after surgery in a young and active cohort of patients with acute mid-substance ACL tears.

The Role of Patient Characteristics in the Success of Nonoperative Treatment of Anterior Cruciate Ligament Injuries

Background: Anterior cruciate ligament (ACL) tears can either be treated nonoperatively with physical therapy and then treated operatively if persistent instability is present, or be directly treated operatively. Advantages of early ACL reconstruction surgery include shorter time from injury to surgery and potentially fewer meniscal injuries, but performing early ACL reconstruction in all patients results in surgery in patients who might not need ACL reconstruction. It is important to assess in which patients nonoperative treatment is successful and which patients will require ACL reconstruction and thus might be better treated surgically in an earlier phase. Purpose: To identify patient characteristics that predict the success of nonoperative treatment. Study Design: Cohort study (Prognosis); Level of evidence, 2. Methods: All patients with complete ACL injuries who were evaluated between 2014 and 2017 at our clinic were included. The minimum follow-up was 2 years. The initial treatment and ultimate ACL reconstruction were reviewed. Univariate analysis was performed using Mann-Whitney U tests and chi-square tests and multivariate analysis using binary logistic regression. Results: A total of 448 patients were included with a median age of 26 years and median Tegner level of 7 and mean Tegner level of 6.4. At initial consultation, 210 patients (47%) were treated nonoperatively with physical therapy and 126 of these patients (60%) ultimately required ACL reconstruction. Nonoperative treatment failed in 88.9% of patients <25 years of age, 56.0% of patients 25 to 40 years, and 32.9% of patients >40 years (P < .001); and 41.9% of patients with Tegner level 3 to 6, and 82.8% of patients with Tegner level 7 to 10. Age <25 years (odds ratio [OR], 7.4; P < .001) and higher Tegner levels (OR, 4.2; P < .001) were predictive of failing nonoperative treatment in multivariate analysis. Patients in the failed nonoperative group had longer time from diagnosis to surgery than the direct reconstruction group (6.2 vs 2.2 months; P < .001), and more frequently had new meniscal injuries (17.4% vs 3.1%; P < .001) at surgery. Conclusion: Nonoperative treatment of ACL injuries failed in 60% of patients and was highly correlated with age and activity level. In patients aged 25 years or younger or participating in higher-impact sports, early ACL reconstruction should be considered to prevent longer delay between injury and surgery, as well as new meniscal injuries.

Bridge-Enhanced Anterior Cruciate Ligament Repair Is Not Inferior to Autograft Anterior Cruciate Ligament Reconstruction at 2 Years: Results of a Prospective Randomized Clinical Trial

Background: Preclinical studies suggest that for complete midsubstance anterior cruciate ligament (ACL) injuries, a suture repair of the ACL augmented with a protein implant placed in the gap between the torn ends (bridge-enhanced ACL repair [BEAR]) may be a viable alternative to ACL reconstruction (ACLR). Hypothesis: We hypothesized that patients treated with BEAR would have a noninferior patient-reported outcomes (International Knee Documentation Committee [IKDC] Subjective Score; prespecified noninferiority margin, –11.5 points) and instrumented anteroposterior (AP) knee laxity (prespecified noninferiority margin, +2-mm side-to-side difference) and superior muscle strength at 2 years after surgery when compared with patients who underwent ACLR with autograft. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: One hundred patients (median age, 17 years; median preoperative Marx activity score, 16) with complete midsubstance ACL injuries were enrolled and underwent surgery within 45 days of injury. Patients were randomly assigned to receive either BEAR (n = 65) or autograft ACLR (n = 35 [33 with quadrupled semitendinosus-gracilis and 2 with bone–patellar tendon–bone]). Outcomes—including the IKDC Subjective Score, the side-to-side difference in instrumented AP knee laxity, and muscle strength—were assessed at 2 years by an independent examiner blinded to the procedure. Patients were unblinded after their 2-year visit. Results: In total, 96% of the patients returned for 2-year follow-up. Noninferiority criteria were met for both the IKDC Subjective Score (BEAR, 88.9 points; ACLR, 84.8 points; mean difference, 4.1 points [95% CI, –1.5 to 9.7]) and the side-to-side difference in AP knee laxity (BEAR, 1.61 mm; ACLR, 1.77 mm; mean difference, –0.15 mm [95% CI, –1.48 to 1.17]). The BEAR group had a significantly higher mean hamstring muscle strength index than the ACLR group at 2 years (98.2% vs 63.2%; P < .001). In addition, 14% of the BEAR group and 6% of the ACLR group had a reinjury that required a second ipsilateral ACL surgical procedure (P = .32). Furthermore, the 8 patients who converted from BEAR to ACLR in the study period and returned for the 2-year postoperative visit had similar primary outcomes to patients who had a single ipsilateral ACL procedure. Conclusion: BEAR resulted in noninferior patient-reported outcomes and AP knee laxity and superior hamstring muscle strength when compared with autograft ACLR at 2-year follow-up in a young and active cohort. These promising results suggest that longer-term studies of this technique are justified. Registration: NCT02664545 (ClinicalTrials.gov identifier)

Joint laxity varies in response to partial and complete anterior cruciate ligament injuries throughout skeletal growth

Anterior cruciate ligament (ACL) injuries are increasingly common in the skeletally immature population. As such there is a need to increase our understanding of the biomechanical function of the joint following partial and complete ACL injury during skeletal growth. In this work, we aimed to assess changes in knee kinematics and loading of the remaining soft tissues following both partial and complete ACL injury in a porcine model. To do so, we applied anterior-posterior tibial loads and varus-valgus moments to stifle joints of female pigs ranging from early juvenile to late adolescent ages and assessed both kinematics and in-situ loads carried in the bundles of the ACL and other soft tissues including the collateral ligaments and the menisci. Partial ACL injury led to increased anterior tibial translation only in late adolescence and small increases in varus-valgus rotation at all ages. Complete ACL injury led to substantial increases in translation and rotation at all ages. At all ages, the medial collateral ligament and the medial meniscus combined to resist the majority of applied anterior tibial load following complete ACL transection. Across all ages and flexion angles, the contribution of the MCL ranged from 45 to 90% of the anterior load and the contribution of the medial meniscus ranged from 14 to 35% of the anterior load. These findings add to our current understanding of age-specific functional properties of both healthy and injured knees during skeletal growth.

Prevalence of anterolateral complex injury and associated injuries in knees with acute complete and partial anterior cruciate ligament injury

Aim: Kaplan fibers, capsule, ligament (ALL) and Iliotibial band are defined as secondary stabilizers of the internal tibial rotation of the knee. These structures have been summarized as the Anterolateral complex (ALC). We aimed to determine the ALC injury prevalence and the association between Anterior cruciate ligament (ACL) and ALC injury patterns. Materials and Methods: MRI scans of ACL injuries were retrospectively evaluated for the presence of the ACL injury pattern (partial or complete), ALL, iliotibial band, Kaplans fiber, meniscus, bone marrow edema (BME) and collateral ligament pathology. The patients were divided into groups according to the ACL injury pattern. The prevalence of injury of the anatomical structures between groups was examined. Results: MRI scans of 152 patients (152 knees) were evaluated. The mean age of the patients was 28.5±8.6 (range, 18-55). 138 patients were male and 14 were female. Complete ACL injury was detected in 127 (83.6%) patients confirmed by MRI and arthroscopic procedure and partial ACL injury was detected in 25 (16.4%) patients confirmed by MRI. 90 (59.2%) patients had an ALL injury, 87 (57.2%) had an iliotibial band injury, 82 (53.9%) patients had a Kaplans fiber injury, 53 (34.9%) patients had a meniscal injury, 99 (65.1%) patients had BME and 70 (46.1%) patients had a collateral ligament injury. In the complete ACL injury group, the ratio of ALL, iliotibial band, Kaplan fiber, meniscal injury, BME, collateral ligament injury was significantly higher than the partial ACL injury group (p 0.05). Conclusion: The prevalence of injury in at least one anatomic structure of ALC was significantly higher in patients with a complete ACL injury (73.2%) than those with partial ACL injury (32%) at our institution. This study demonstrated that ALC injuries were statistically higher as well as meniscal injuries, BME, collateral ligament injuries after complete ACL injury compared to partial ACL injury.