Acute Anterior Cruciate Ligament Research Articles

Comparison of Side-to-Side Difference in Posterior Tibial Slope in Knees With Acute Versus Chronic Anterior Cruciate Ligament Deficiency.

The posterior tibial slope (PTS) is an important feature in knee joint biomechanics and indicates anterior-posterior knee stability. Increased PTS is a known risk factor for both primary anterior cruciate ligament (ACL) rupture and postreconstruction rerupture. To investigate the effect of long-term exposure to ACL deficiency on the PTS and the sagittal anatomy of the proximal tibia. Cross-sectional study; Level of evidence, 3. A total of 44 patients (38 men, 6 women) with a history of knee injury and ACL rupture confirmed by magnetic resonance imaging and physical examination were included in this study. Patients were divided into those with chronic ACL deficiency (group 1: injured ≥5 years prior; n = 22) and acute ACL deficiency (group 2: injured <1 year prior; n = 22). The medial and lateral tibial plateau PTS and anterior tibial translation were measured on monopodal weightbearing knee radiographs at 20° of flexion. The mechanical tibiofemoral angle (MTFA) and the medial proximal tibial angle (MPTA) were measured using an orthoroentgenogram. The side-to-side difference between the affected and unaffected knees was also calculated for all measurements. The mean duration of exposure to ACL deficiency was 7.6 years (range, 5-15 years) in group 1 and 4.4 months (range, 1-11 months) in group 2. Regarding the side-to-side differences in angular measurements, a higher medial PTS (affected vs unaffected: 12.4° vs 10.1°; P = .007), higher lateral PTS (11° vs 8.9°; P = .011), and increased varus alignment on both the MTFA (4.3° vs 2.4°; P = .036) and the MPTA (84.9° vs 86.3°; P = .033) were found in group 1, while no significant differences in angular measurements were found in group 2. Compared with group 2, patients in group 1 had a significantly higher side-to-side difference in the medial PTS (2.3° vs 0.1°; P = .0001), lateral PTS (2.1° vs 0.4°; P = .0001), and MPTA (1.4° vs 0.1°; P = .002). This study showed that the affected knees of patients with chronic ACL deficiency (≥5 years) had higher medial and lateral PTS compared with the unaffected contralateral knees. Therefore, when planning ACL reconstruction for patients with a history of long-term ACL deficiency, it is crucial to measure the preoperative PTS accurately.

High incidence of RAMP lesions and a nonnegligible incidence of anterolateral ligament and posterior oblique ligament rupture in acute ACL injury.

The purpose of this study was to assess the frequency of medial collateral ligament (MCL), posterior oblique ligament (POL) and anterolateral ligament (ALL) tears and different types of RAMP lesions of patients with verified acute anterior cruciate ligament (ACL) tears by magnetic resonance imaging (MRI). MRI was performed on patients with a clinical diagnosis of acute ACL injury. Patients were eligible for inclusion if they had an initially clinically noted ACL tear confirmed on MRI within 30 days of trauma. A total of 146 patients were included in the study, 42 (28.8%) females and 104 (71.2%) males. The mean age at MRI was 27.2 ± 9.4 years, and the mean time from injury to MRI was 15.7 ± 7.8 days. Thirty-four (23.3%) patients had a complete MCL lesion, 32 (21.9%) had a complete POL lesion and 28 (19.2%) had a complete ALL lesion. One hundred and fourteen patients (78.1%) presented with RAMP lesions, while 20 (13.7%) patients reported other meniscal lesions. The mean medial and lateral tibial slopes were 4.0° ± 2.7° and 4.0° ± 3.1°, respectively. Only 10 (6.8%) patients reported no lesions associated with ACL rupture. The most common injuries were isolated RAMP type 3 (18-12.3%) and isolated RAMP type 1 (17-11.6%). Thirteen (8.9%) patients had a combination of MCL, POL and ALL rupture. Isolated lesions of the ACL are extremely rare. In most cases, a single RAMP lesion should be investigated. In the presence of MCL injury, POL injury should always be suspected as well, while nearly 20% of patients present a rupture of the ALL. About one in 10 patients had three lesions (MCL, ALL and POL), and most of them had a combined RAMP lesion. Level IV.

A Systematic Review of Bone Bruise Patterns following Acute Anterior Cruciate Ligament Tears: Insights into the Mechanism of Injury.

(1) Background: The purpose of this systematic review was to determine the prevalence of bone bruises in patients with anterior cruciate ligament (ACL) injuries and the location of the bruises relative to the tibia and femur. Understanding the relative positions of these bone bruises could enhance our comprehension of the knee loading patterns that occur during an ACL injury. (2) Methods: The MEDLINE, EMBASE, and the Cochrane Library databases were searched for studies that evaluated the presence of bone bruises following ACL injuries. Study selection, data extraction, and a systematic review were performed. (3) Results: Bone bruises were observed in 3207 cases (82.8%) at the lateral tibia plateau (LTP), 1608 cases (41.5%) at the medial tibia plateau (MTP), 2765 cases (71.4%) at the lateral femoral condyle (LFC), and 1257 cases (32.4%) at the medial femoral condyle (MFC). Of the 30 studies, 11 were able to assess the anterior to posterior direction. The posterior LTP and center LFC were the most common areas of bone bruises. Among the 30 studies, 14 documented bone bruises across all four sites (LTP, MTP, LFC, and MFC). The most common pattern was bone bruises appearing at the LTP and LFC. (4) Conclusions: The most frequently observed pattern of bone bruises was restricted to the lateral aspects of both the tibia and femur. In cases where bone bruises were present on both the lateral and medial sides, those on the lateral side exhibited greater severity. The positioning of bone bruises along the front-back axis indicated a forward shift of the tibia in relation to the femur during ACL injuries.

Injuries to both anterolateral ligament and Kaplan fiber of the iliotibial band do not increase preoperative pivot-shift phenomenon in ACL injury

BackgroundTo assess the incidence of anterolateral ligament (ALL) and Kaplan fiber of the iliotibial band (KF) injuries in patients with acute anterior cruciate ligament (ACL) injury on magnetic resonance imaging (MRI), and to investigate the association between these injuries and the magnitude of preoperative pivot-shift test. MethodOne-hundred and five patients with primary ACL injury were retrospectively reviewed. ALL injury and KF injury were assessed by preoperative MRI, and subjects were allocated into four groups: Group A, neither injury; Group B, only ALL injury; Group C, only KF injury; Group D, simultaneous ALL and KF injuries. Before ACL reconstruction, tibial acceleration during the pivot-shift test was measured by an electromagnetic measurement system, and manual grading was recorded according to the International Knee Documentation Committee (IKDC) guideline. ResultsIn MRI, the ALL was identified in 104 patients (99.1%) and KF in 99 patients (94.3%). ALL and KF injuries were observed in 43 patients (43.9%) and 23 patients (23.5%), respectively. Patient distribution to each group was as follows; Group A: 43 patients (43.9%), Group B: 32 patients (32.7%), Group C: 12 patients (12.2%), Group D: 11 patients (11.2%). No significant differences were observed in tibial acceleration, and manual grading among the four groups. ConclusionSimultaneous injury to both ALL and KF was uncommon, and preoperative pivot-shift phenomenon did not increase even in those patients. The finding suggests that the role of ALL and KF in controlling anterolateral rotatory knee laxity may be less evident in the clinical setting compared to a biomechanical test setting.

Effect of Stem Cell Injections in an Acute Anterior Cruciate Ligament Injury

Effect of Stem Cell Injections in an Acute Anterior Cruciate Ligament Injury

Conservative Treatment Using Platelet-Rich Plasma for Acute Anterior Cruciate Ligament Injuries in Highly Active Patients: A Retrospective Survey.

Background The recommended treatment for anterior cruciate ligament (ACL) injuries in active, sports-oriented patients is reconstructive surgery in order to regain stability and prevent secondary meniscal injuries. However, ACL reconstruction requires a long recovery period and poses issues such as decreased muscle strength due to tendon harvesting and postoperative osteoarthritis (OA) progression, thereby raising significant expectations for the advancement of conservative treatments. Recent studies have shown that platelet-rich plasma (PRP) therapy, which utilizes the tissue repair-promoting property of platelets, is effective for ACL injuries. Methods We administered PRP therapy within six weeks after ACL injury in patients who expressed the desire for an early return to sports through conservative care. After the treatment, patients wore a simple brace that limited deep flexion but placed no restrictions on weight bearing. Four months was the standard goal established for returning to pre-injury condition, and, depending on the target level, timing, and knee condition, we adjusted the additional PRP treatments and rehabilitation approach, gradually authorizing the patients' return to sport. We assessed the ligament repair status by magnetic resonance imaging (MRI) just before the full return to sports.A retrospective survey was conducted to evaluate the status of ligament repair and the condition of return-to-sport in patients with ACLinjuries who underwent conservative treatment using PRP. Results The average patient age was 32.7 years and the average treatment was 2.8 PRP sessions. MRI evaluations confirmed that ligament continuity was regained in all cases. All the patients returned to their pre-injury level (Tegner Activity Scale 7.0) in an average of 139.5 days, but there was one instance of re-rupture following the return to sports. Conclusion All patients with ACL injury who underwent PRP therapy regained ligament continuity and returned to sport successfully with only one case of re-rupture.

Acute Anterior Cruciate Ligament Reconstruction Performed Within 10 Days of Injury Does Not Increase Risk of Postoperative Arthrofibrosis: A Systematic Review and Meta-analysis.

The optimal timing of anterior cruciate ligament (ACL) reconstruction (ACLR) remains a controversial topic. Previous reviews have demonstrated that there are no differences between early and delayed ACLR; however, these studies have been limited by heterogeneous definitions of acute ACL injury. To evaluate postoperative patient functional outcomes and risk for arthrofibrosis after acute arthroscopic ACLR performed ≤10 days after injury. Systematic review; Level of evidence, 4. A systematic review was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using multiple medical databases. Inclusion criteria were studies that evaluated postoperative range of motion outcomes for patients undergoing ACLR ≤10 days after initial ACL injury. For included comparative studies comparing patient groups undergoing ACLR ≤10 days and patients undergoing "delayed" ACLR after ≥3 weeks of initial injury, quantitative analysis was performed to assess for differences in postoperative arthrofibrosis, reoperation rates, and patient-reported outcomes between groups. DerSimonian-Laird binary random-effects models were constructed to quantitatively describe the association between the ACLR time period and patient outcomes by generating effect estimates in the form of odds ratios with 95% CIs. Qualitative analysis was performed to describe variably reported patient outcomes and the risk of arthrofibrosis after ACLR for noncomparative studies. Screening yielded 6 full-text articles with 448 patients who underwent ACLR (296 ACLR <10 days, 152 ACLR >3 weeks), with a pooled mean age of 28.1 years. For studies amenable to quantitative analysis, there were no significant differences between ACLR performed ≤10 days and ACLR performed at the 3-week point or after in terms of postoperative stiffness (3 studies; odds ratio, 1.27; P = .508), Tegner scores (2 studies; mean difference, -0.056; P = .155), or reoperation for stiffness (3 studies; odds ratio, 0.869; P = .462). The overall incidence of postoperative arthrofibrosis after 12 months of follow-up was 11 of 296 (3.7%) for ACLRs performed ≤10 days versus 6 of 152 (3.9%) for those performed at the 3-week point or after. ACLR performed ≤10 days after the inciting injury does not increase the risk of postoperative arthrofibrosis and demonstrates similar patient-reported outcomes compared with ACLR performed at the 3-week point or after.

Comparison of immediate versus optional delayed surgical repair for treatment of acute anterior cruciate ligament injury through a parallel, multicentric, pragmatic randomized controlled trial - IODA trial.

Standard care for anterior cruciate ligament (ACL) injuries often includes surgical reconstruction of the ACL. However, two randomized controlled trials [1, 2] (RCT) concluded that conservative treatment does not result in inferior clinical outcomes compared to immediate ACL reconstruction. More research is needed to verify these results and assess whether patient-specific parameters determine if a patient would benefit from one treatment option over the other. This is a pragmatic, multi-center RCT with two parallel groups. Patients with an acute ACL injury will be recruited from Belgian hospitals. Patients will be randomized to conservative treatment (rehabilitation + optional delayed surgery) or immediate ACL reconstruction (< 12 weeks). The primary outcome is the Knee injury and Osteoarthritis Outcome Score (KOOS) at 7 months (short term) and 1-year long term) post-injury. These following additional outcomes will be administered at 4 and 7 months (short term) and 1, 2, and 3 years post-injury (long term): patient-reported outcomes concerning knee symptoms, knee function and quality of life, functional knee tests, time to return to pre-injury activity level and return to work, structural knee joint damage and cartilage health (only at 4 months and 3 years post-injury), as well as adverse events such as re-rupture rates. Furthermore, the secondary objective is to identify (through a predictive analysis) individuals who would benefit the most from early reconstruction versus those who should rather be treated conservatively. This large RCT will assess the clinical effectiveness of both surgical and conservative treatment. In addition, it will be the first study that provides insights into which patient-specific factors predict successful outcomes after conservative treatment of ACL injuries. These results will be the first step toward early patient identification regarding treatment decisions. This is urgently needed to avoid (1) delayed surgeries and prolonged rehabilitation and (2) unnecessary surgeries. this trial was registered on ClinicalTrials.gov (NCT05747079) on 10/02/2023.

Incidence of and Risk Factors for Arthrogenic Muscle Inhibition in Acute Anterior Cruciate Ligament Injuries: A Cross-Sectional Study and Analysis of Associated Factors From the SANTI Study Group

Background: Arthrogenic muscle inhibition (AMI) is a process in which neural inhibition after injury or surgery to the knee results in quadriceps activation failure and knee extension deficit. Purpose: To determine the incidence and spectrum of the severity of AMI after acute anterior cruciate ligament (ACL) injury using the Sonnery-Cottet classification, to determine the interobserver reliability of the classification system, and to investigate potential important factors associated with AMI after ACL injury. Study Design: Case-control study; Level of evidence, 3. Methods: Consecutive patients who had an acute ACL injury between October 2021 and February 2022 were considered for study inclusion. Eligible patients underwent a standardized physical examination at their first outpatient appointment. This included an assessment of quadriceps inhibition, identification of any extension deficits, and grading of AMI and its reversibility according to the Sonnery-Cottet classification. Results: A total of 300 consecutive patients with acute ACL ruptures were prospectively enrolled in the study. Of them, 170 patients (56.7%) had AMI. Patients evaluated with AMI showed a significantly inferior Lysholm score, International Knee Documentation Committee score, Simple Knee Value, and Knee injury and Osteoarthritis Outcome Score than patients without AMI (P < .0001). Multivariate analysis revealed that the presence of effusion, concomitant injuries, and high pain scores were associated with a significantly greater risk of AMI. Additional associations with the presence of AMI included a short duration between injury and evaluation, the use of crutches, and using a pillow as a support at night. In contrast, a previous ACL injury was associated with significantly lower odds of developing AMI (OR, 0.025; 95% CI, 0-0.2; P = .014). Among the 170 patients with AMI, 135 patients (79%) showed a resolution of their inhibition at the end of the consultation after application of simple exercises; the remaining 35 patients required specific rehabilitation. Interobserver reliability of the classification system was almost perfect (95% CI, 0.86-0.99). Conclusion: AMI occurs in over half of patients with acute ACL injuries. When it occurs, it is easily reversible in the majority of patients with simple exercises targeted at abolishing AMI. The presence of “red flags” should increase the index of suspicion for the presence of AMI, and these include the presence of an effusion, high pain scores, a short time between injury and evaluation, multiligament injuries, the use of crutches, and using a pillow as a support at night. Patients with a history of ipsilateral or contralateral ACL injury are at a significantly lower risk of AMI than those with a first-time ACL injury.

Refixation of the anterior cruciate ligament: A biomechanical analysis of suture techniques in a porcine model.

Refixation of acute anterior cruciate ligament (ACL) tears represents an increasingly popular treatment option. Systematic evaluations of various suture technique parameters are still pending. We therefore aimed to evaluate the mechanical pull-out outcomes of various suture methods for optimization of ACL refixation. Sixty fresh knees from mature domestic pigs were dissected and the femoral attachment of the ACL was peeled off. The 60 knees were divided in 10 groups and sutured as follows: (A) one suture (1, 2, 4 and 6 passes), (B) two sutures (2, 4 and 6 passes each; sutures knotted together as a loop) and (C) two sutures (2, 4 and 6 passes each, sutures knotted separately). The pull-out test was conducted using a validated electrodynamic testing machine. First occurrence of failure, maximum pull-out load and stiffness were measured. Suture failure was defined as pull-out of the ACL. Two-point fixation, using two sutures, with at least two passes, showed the most favourable biomechanical stability. The maximum pull-out load was significantly higher with two sutures (529.5 N) used compared to one (310.4 N), p < 0.001. No significant differences were found for maximum pull-out loads between two-point fixation versus one-point fixation but stiffness was significantly higher with two-point fixation (107.4 N/mm vs. 79.4 N/mm, p < 0.001). More passes resulted in higher maximum pull-out loads. The results suggest using two independent sutures, refixed separately and at least two suture passes, is appropriate for ACL refixation. More suture passes provide additional strength but are technically challenging to achieve during surgery. Level IV.

Comparison of the therapeutic effects between ligament advanced reinforcement system artificial ligament and four-strand hamstring tendon autograft in patients with acute anterior cruciate ligament injury.

Comparison of the therapeutic effects between ligament advanced reinforcement system artificial ligament and four-strand hamstring tendon autograft in patients with acute anterior cruciate ligament injury.

Outcomes of Lateral Meniscal Oblique Radial Tear Repair Compared With Intact Meniscus After ACL Reconstruction: A Cohort Study.

Recently, the posterior horn lateral meniscal oblique radial tear (LMORT) was identified in 12% of acute anterior cruciate ligament (ACL) injuries. However, patient-reported outcomes for repair of this relatively common tear have not been reported. To determine the minimum 2-year functional outcomes after LMORT repair at the time of ACL reconstruction (ACLR) compared to a matched cohort of patients who underwent isolated ACLR (iACLR). Cohort study; Level of evidence, 3. Included were 100 patients (mean age at surgery, 21 years; range, 13-45 years) who underwent primary ACLR between 2010 and 2018. The mean follow-up period was 4.1 ± 2.0 years (range, 2.0-9.2 years). A total of 50 patients with surgically repaired LMORT type 3 or type 4 lesions, defined as partial or complete tears >10 mm from the root (LMORT group) were matched 1:1 based on age, date of surgery, and graft choice with 50 patients who underwent iACLR (iACLR group). The postoperative outcomes were compared between groups using the International Knee Documentation Committee subjective score (sIKDC) and the Tegner activity scale. An updated medical history was obtained via the electronic medical record to determine any subsequent complications and reoperations. There was 1 ACL graft failure in each group as well as 5 (10%) reoperations per group. None of the patients in the LMORT group necessitated a lateral meniscal revision repair or partial meniscectomy. The LMORT and iACLR groups reported comparable sIKDC scores (92.5 ± 6.8 vs 91.9 ± 8.2, respectively; P = .712) as well as Tegner scores (6.7 ± 1.8 vs 6.6 ± 1.8, respectively; P = .910) at final follow-up. No failures of the LMORT repairs were reported. The study findings demonstrated that reoperations, graft failure rates, patient-reported outcomes, and patient activity levels at ≥2 years after type 3 and 4 LMORT repairs at the time of ACLR compared favorably with those of a matched cohort of patients who underwent iACLR with intact meniscus.

Incidence and risk factors for arthrogenic muscle inhibition in acute anterior cruciate ligament injuries: A cross sectional study and analysis of associated factors

Incidence and risk factors for arthrogenic muscle inhibition in acute anterior cruciate ligament injuries: A cross sectional study and analysis of associated factors

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

BackgroundConcomitant lateral meniscal (LM) injuries are common in acute anterior cruciate ligament (ACL) ruptures. However, the effect of addressing these injuries with various treatment methods during primary ACL reconstruction (ACLR) on patient-reported outcomes (PROs) is unknown. Therefore, the purpose of this study was to compare postoperative Knee injury and Osteoarthritis Outcome Score (KOOS) at 2-, 5-, and 10-years after isolated primary ACLR to primary ACLR with various treatment methods to address concomitant LM injury.MethodsThis study was based on data from the Swedish National Knee Ligament Registry. Patients ≥ 15 years with data on postoperative KOOS who underwent primary ACLR between the years 2005 and 2018 were included in this study. The study population was divided into five groups: 1) Isolated ACLR, 2) ACLR + LM repair, 3) ACLR + LM resection, 4) ACLR + LM injury left in situ, and 5) ACLR + LM repair + LM resection. Patients with concomitant medial meniscal or other surgically treated ligament injuries were excluded.ResultsOf 31,819 included patients, 24% had LM injury. After post hoc comparisons, significantly lower scores were found for the KOOS Symptoms subscale in ACLR + LM repair group compared to isolated ACLR (76.0 vs 78.3, p = 0.0097) and ACLR + LM injury left in situ groups (76.0 vs 78.3, p = 0.041) at 2-year follow-up. However, at 10-year follow-up, no differences were found between ACLR + LM repair and isolated ACLR, but ACLR + LM resection resulted in significantly lower KOOS Symptoms scores compared to isolated ACLR (80.4 vs 82.3, p = 0.041).ConclusionThe results of this study suggest that LM injury during ACLR is associated with lower KOOS scores, particularly in the Symptoms subscale, at short- and long-term follow-up. However, this finding falls below minimal clinical important difference and therefore may not be clinically relevant.Level of EvidenceIII.

Correlation Between the Location and Distance of Kissing Contusions and Knee Laxity in Acute Noncontact ACL Injury

Background: Bone bruise (BB) and kissing contusion are common features of acute anterior cruciate ligament (ACL) injury on magnetic resonance imaging (MRI). The correlation between the location and distance of kissing contusions and knee laxity remains unclear. Purpose: To determine the significance of different patterns of BB in acute noncontact ACL injury and assess the correlation between the location and distance of kissing contusions and the severity of knee laxity. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 205 patients with acute noncontact ACL injury undergoing arthroscopic treatment between January 2021 and May 2022 were included in this retrospective analysis. Patients were grouped according to the different patterns of BB. The type of ACL injury and concomitant injuries were analyzed on MRI and confirmed by arthroscopy. Anterior knee laxity was assessed by the Ligs digital arthrometer and stress radiography, and rotational knee laxity was assessed by the intraoperative pivot-shift test. The MRI parameters of the location and distance of kissing contusions were measured to assess their correlations with the severity of knee laxity. Results: Of the 205 patients with acute noncontact ACL injury, 38 were in the non-BB group and 167 were in the BB group, the latter including 32 with the isolated BB on the lateral tibial plateau and 135 with kissing contusions. There was no significant difference in the mean time from initial injury to MRI scan between the non-BB group and the BB group (14.34 ± 2.92 vs 15.17 ± 2.86 days; P = .109) or between the isolated BB subgroup and the kissing contusion subgroup (14.94 ± 2.92 vs 15.23 ± 2.85 days; P = .605). The side-to-side difference (SSD) in anterior knee laxity and the incidences of complete ACL injury, concomitant injuries, and high-grade pivot-shift test were significantly higher in the BB group than in the non-BB group, and in the kissing contusion subgroup compared with the isolated BB subgroup. The kissing contusion index of the lateral femoral condyle (LFC) and the sagittal distance of kissing contusions were significantly correlated with the SSD in anterior knee laxity and the grade of pivot-shift test (P < .001). Conclusion: The presence of BB, in particular the appearance of kissing contusions, was related to greater knee laxity and higher incidences of complete ACL injury and concomitant injuries in acute noncontact ACL injury. For patients with kissing contusions, as the location of BB on the LFC moved forward and the distance between kissing contusions increased, anterior and rotational knee laxity became more serious.

A Systemic and Local Comparison of Senescence in an Acute Anterior Cruciate Ligament Injury-A Pilot Case Series.

Senescence, a characteristic of cellular aging and inflammation, has been linked to the acceleration of osteoarthritis. The purpose of this study is to prospectively identify, measure, and compare senescent profiles in synovial fluid and peripheral blood in patients with an acute knee injury within 48 h. Seven subjects, aged 18-60 years, with an acute ACL tear with effusion were prospectively enrolled. Synovial fluid and peripheral blood samples were collected and analyzed by flow cytometry, using senescent markers C12FDG and CD87. The senescent versus pro-regenerative phenotype was probed at a gene and protein level using qRT-PCR and multiplex immunoassays. C12FDG and CD87 positive senescent cells were detected in the synovial fluid and peripheral blood of all patients. Pro-inflammatory IL-1β gene expression measured in synovial fluid was significantly higher (p = 0.0156) than systemic/blood expression. Senescent-associated factor MMP-3 and regenerative factor TIMP-2 were significantly higher in synovial fluid compared to blood serum. Senescent-associated factor MMP-9 and regenerative factor TGFβ-2 were significantly elevated in serum compared to synovial fluid. Correlation analysis revealed that C12FDG++/CD87++ senescent cells in synovial fluid positively correlated with age-related growth-regulated-oncogene (ρ = 1.00, p < 0.001), IFNγ (ρ = 1.00, p < 0.001), IL-8 (ρ = 0.90, p = 0.0374), and gene marker p16 (ρ = 0.83, p = 0.0416). There is an abundance of senescent cells locally and systemically after an acute ACL tear without a significant difference between those present in peripheral blood compared to synovial fluid. This preliminary data may have a role in identifying strategies to modify the acute environment within the synovial fluid, either at the time of acute ligament injury or reconstruction surgery.

The Resolution of Kaplan Fiber Injuries Is Observed in a Majority of Cases at 9 Months After Acute Primary Anterior Cruciate Ligament Reconstruction: A Radiological Study

Background: The natural history of Kaplan fiber (KF) injuries after acute primary anterior cruciate ligament (ACL) reconstruction (ACLR) remains unknown. Purpose/Hypothesis: The purpose of this study was to evaluate the temporal change in the magnetic resonance imaging (MRI) appearance of the KF complex after acute primary ACLR. It was hypothesized that KF injuries would resolve with time. Study Design: Case series; Level of evidence, 4. Methods: A retrospective MRI analysis was conducted on 89 patients with ACL-injured knees to assess the change in the radiological appearance of KFs after primary ACLR. Patients who had undergone index MRI and ACLR within 90 days of the injury and further MRI at 9 months after surgery were included. Diagnostic criteria to identify radiological evidence of a KF injury and its subsequent resolution were applied, including the presence of high signal intensity on fluid-sensitive sequences, which is indicative of a pathological process radiologically. The proximity of KFs to the femoral cortical suspensory device (CSD) was noted on MRI scans and quantified in millimeters. Results: A KF injury was identified in 30.3% (27/89) of patients, with isolated high signal intensity observed in an additional 18.0% (16/89). At 9 months, MRI evidence of the reconstitution of the KF complex was found in 51.9% (14/27) of patients, with persistent discontinuity in the remaining patients (13/27). All patients (16/16) with isolated high signal intensity had complete resolution on repeat MRI scans. KF thickening was observed in 26.1% (12/46) of patients with previously healthy KFs and in 25.0% (4/16) with isolated high signal intensity. The CSD was positioned in close proximity (≤6 mm) to the center of the KF attachment in 61.8% (55/89) of patients, and this was associated with increased rates of KF thickening. Conclusion: The KF injury resolved radiologically in over half of the patients at 9 months after acute primary ACLR. High signal intensity in the region of the KFs on index MRI scans resolved in all cases, with evidence of residual KF thickening in only one-quarter of cases on repeat MRI scans, equivalent to the rate in those with healthy KFs. As such, it is not advisable to use high signal intensity on preoperative MRI scans as the sole criterion for the diagnosis of a KF injury. The position of the CSD after ACLR was intimately related to the KF attachment in the majority of patients, which was associated with KF thickening on postoperative MRI scans.

Poster 126: Chronic ACL Injury Patients Have Lower Levels of Pro-Inflammatory Biomarkers in their Synovial Fluid and Worse ACLOAS Score at the Time of Surgery Than Those with Acute ACL Injury: A Cohort Study

Objectives: The relationship between structural abnormalities and inflammatory changes in the synovial fluid following ACL injury has not been well defined. The purpose of this study is to compare MRI findings and concentration of inflammatory biomarkers in the synovial fluid (SF) of acute and chronic anterior cruciate ligament (ACL) injury patients. Methods: Patients undergoing surgery for ACL injury from October 2011 to December 2021 were included in a database of patients who had SF samples collected at the time of surgery. From this cohort, 82 patients with acute ACL injury and 28 patients with chronic ACL injury were identified. All patients underwent a preoperative MRI examination of the knee and SF was aspirated from the operative knee prior to the surgical incision and concentrations of inflammatory biomarkers were quantified. MRI examinations were reviewed by a fellowship-trained musculoskeletal radiologist to assess radiographic features of acute and chronic knee injury using the validated ACLOAS system. Nonparametric tests were used to compare demographic factors, MRI findings, clinical symptoms, and SF inflammatory biomarkers between acute versus chronic ACL injury patients. A generalized linear model was used to assess the relationship of each SF biomarker with the ACLOAs subscores. Results: For acute ACL injury patients, mean time from injury to MRI and injury to surgery was 14 ± 35 days and 49 ± 38 days, respectively. The mean time from injury to MRI and injury to surgery was 3.2 ± 3.7 years and 3.4 ± 3.8 years, respectively, for those with chronic ACL injury. There were no significant demographic differences between groups; age (acute: 31.62 ± 8.02 years, chronic: 33.70 ± 10.60 years, p=0.130), sex (acute: 51.2% males, chronic: 57.1%, p=0.588), or body mass index (acute: 5.5 ± 4.4 kg/mm2, chronic: 25.3 ± 3.6 kg/mm2, p=0.931). Acute ACL injury patients had higher bone marrow edema severity scores (p&lt;0.001), Hoffa’s synovitis score (p=0.002), and effusion severity scores (p&lt;0.001). Chronic ACL injury patients had higher cartilage degeneration severity scores (p&lt;0.001), prevalence of meniscus tears (p=0.003), and meniscus tear severity scores (p&lt;0.001). Acute ACL injury patients had significantly higher synovial fluid levels of IL-6 (p=0.032), VEGF (p=0.002), TIMP1 (p&lt;0.001), IL1-RA (p=0.003), and MMP3 (p&lt;0.001) than chronic ACL injury patients. The generalized linear model revealed that after adjusting for age, sex, BMI, and time from injury to surgery, increased VEGF (p=0.003) and MMP3 (p=0.012) were associated with higher effusion score. MMP-3 was associated with a higher bone marrow edema score (p=0.034), and RANTES was associated with both a higher meniscus severity score (p=0.027) and increased cartilage lesions in the chronic ACL injury cohort. Conclusions: The findings from this study suggest that despite having more severe cartilage degeneration and a higher prevalence of meniscus pathology, chronic ACL injury patients had lower levels of synovial fluid inflammatory biomarkers at time of surgery compared to acute ACL injury patients. Additionally, we found that in chronic injuries, RANTES was associated with worse ACLOAS cartilage scores.

Poster 148: Preoperative Platelet Rich Plasma Injections Decreases Inflammatory and Chondrodegenerative Biomarkers in Patients with Acute Anterior Cruciate Ligament Tears and Reconstruction: A Pilot Study

Objectives: Post-traumatic osteoarthritis occurs at an alarming rate after ACL injury and surgery. The purpose of this study was to compare the effect of two, pre-operative PRP injections upon the progression of inflammatory and chondrodegenerative biomarkers to the natural progression before ACL reconstruction surgery. Our hypothesis was that pre-operative PRP injections would decrease the chondrotoxicity of the presurgery knee fluid. Methods: Participants were randomized to either a control or intervention group. Both groups received joint aspirations within the first 10 days following ACL injury (Time 1). In addition to joint aspiration at Time 1, the PRP group received a PRP injection at Time 1 and an additional PRP injection at a second visit 5-12 days after the initial visit. Synovial fluid samples were harvested in both groups at the time of ACL reconstruction (Time 2). ELISA was performed on all samples to detect cytokine levels of IL-1B, IL-10, IL-6, GM-CSF, IL-5, IFN-γ, TNF-⍺, IL-2, IL-4, and IL-8 Results: A total 24 participants were enrolled, final analysis was completed on 8 participants in the control group and 9 participants in the intervention group. The control group demonstrated a change in concentration (Δ1à2) between time 1 and time 2 that was not statistically significant for any cytokines p&gt;0.05, except for a statistically significant decrease in IL-8 (p=0.005). The intervention group demonstrated a decrease in all cytokine concentrations that was statistically significant for all cytokines p&lt;0.05, except for IL-8 (p=0.074). When comparing the control group to the intervention group at time 1, no significant difference was seen between cytokine concentrations (p&gt;0.05). Likewise, comparing the control group to the intervention group at time 2, no significant difference was seen between cytokine concentrations (p&gt;0.05). The magnitude of decrease was larger in the intervention group than the control group, but with comparison of means between groups there was not a statistically significant difference. The natural history for these biomarkers is a decrease but at a variable rate/amount. Preoperative intervention with PRP has the potential to consistently alter the concentration of chondrodestructive proteins. Conclusions: Intervention with aspiration and 2 injection series of PRP in the acute ACL injured knee resulted in greater reduction in effusion inflammatory markers than control. This may suggest a treatment modality to improve perioperative pain, function and possibly alter the course of post trauma arthritis in these patients, without the deleterious effect of steroid injection. Long term study and follow up is required to determine if intervention alters the natural history of post traumatic arthritis. [Table: see text][Table: see text]

Treatment for Acute Anterior Cruciate Ligament Tear in Young Active Adults

BackgroundAnterior cruciate ligament (ACL) injury of the knee is common in young active adults and often has severe and sometimes lifelong consequences. The clinical management of this injury remains debated. A prior trial of early versus delayed optional ACL repair showed no differences in outcomes at 2 years.MethodsWe present the 11-year follow-up of a randomized clinical trial involving 121 young active adults (mean age 26yo, 74% male) with an acute sports-related ACL tear. We compared patient-reported and radiographic outcomes between those randomized to receive early ACL reconstruction (ACLR) followed by exercise therapy (N=62) and those treated with early exercise therapy plus optional delayed ACLR (N=59). The primary end point at 11 years was change from baseline in the mean of four subscales of the Knee Injury and Osteoarthritis Outcome Score (KOOS) — pain, symptoms, function in sports and recreation, and knee-related quality of life (KOOS4; range of scores, 0 [worst] to 100 [best]; minimal important change=9).ResultsIn all, 88% of the cohort followed up at 11 years (53/62 in the early vs. 54/59 in the optional late ACL repair groups), and 52% of those assigned to optional delayed ACLR underwent ACLR. Mean improvement in KOOS4 from baseline to 11 years was 46 points for those assigned to early ACLR plus exercise therapy and 45 points for those assigned to exercise therapy plus optional delayed ACLR (between-group difference, 1.6 points; 95% confidence interval [CI], −8.8 to 5.6; P=0.67 after adjustment for baseline score, full analysis set). About two thirds of the full cohort reported meeting the case definition for a “patient-acceptable symptom state” (KOOS4 patient-acceptable symptom state threshold value=79), whereas 44% had developed radiographic osteoarthritis of their injured knee. Mean summed incident radiographic osteoarthritis feature scores, scores range from 0 to 30 where higher scores indicate more severe joint damage, were 2.4 for the group assigned to early ACLR and 1.0 for the group assigned to exercise therapy plus optional delayed ACLR (mean difference, 1.0; 95% CI, 0.1 to 1.9).ConclusionsAt 11-year follow-up, among young active adults with acute ACL tears assigned to early ACLR plus exercise versus initial exercise therapy with the option of delayed ACLR, there were no differences in patient-reported outcomes. (Funded by the Swedish Research Council; ISRCTN number, ISRCTN84752559.)