Inhibition of Phlpp1 preserves the mechanical integrity of articular cartilage in a murine model of post-traumatic osteoarthritis.

OBJECTIVE: Phlpp1 inhibition is a potential therapeutic strategy for cartilage regeneration and prevention of post-traumatic osteoarthritis (PTOA). To understand how Phlpp1 loss affects cartilage structure, cartilage elastic modulus was measured with atomic force microscopy (AFM) in male and female mice after injury. METHODS: Osteoarthritis was induced in male and female Wildtype (WT) and Phlpp1-/- mice by destabilization of the medial meniscus (DMM). At various timepoints post-injury, activity was measured, and knee joints examined with AFM and histology. In another cohort of WT mice, the PHLPP inhibitor NSC117079 was intra-articularly injected 4 weeks after injury. RESULTS: Male WT mice showed decreased activity and histological signs of cartilage damage at 12 but not 6-weeks post-DMM. Female mice showed a less severe response to DMM by comparison, with no histological changes seen at any time point. In both sexes the elastic modulus of medial condylar cartilage was decreased in WT mice but not Phlpp1-/- mice after DMM as measured by AFM. By 6-weeks, cartilage modulus had decreased from 2 MPa to 1 MPa in WT mice. Phlpp1-/- mice showed no change in modulus at 6-weeks and only a 25% decrease at 12-weeks. The PHLPP inhibitor NSC117079 protected cartilage structure and prevented signs of OA 6-weeks post-injury. CONCLUSIONS: AFM is a sensitive method for detecting early changes in articular cartilage post-injury. Phlpp1 suppression, either through genetic deletion or pharmacological inhibition, protects cartilage degradation in a model of PTOA, validating Phlpp1 as a therapeutic target for PTOA.

Diagnostic Accuracy of MRI in Knee Meniscus Tear and ACL Injury.

Objective: Knee injuries are very common and may lead to other secondary injuries if effective treatment is lacking. In addition to standardized physical examination, magnetic resonance imaging (MRI) is sometimes considered an aid in the diagnosis of knee trauma. In order to have a more accurate diagnosis of knee injuries, we compared MRI with arthroscopic findings in this study to evaluate the diagnostic accuracy of MRI for meniscal tears and anterior cruciate ligament injuries of the knee. Methods: One hundred and ten patients with suspected meniscal tears and anterior cruciate ligament injuries of the knee who were admitted to our hospital from June 2020 to June 2022 were selected as study subjects, and the clinical data of the patients were retrospectively analyzed. All patients underwent MRI for preoperative diagnosis, and the sensitivity, specificity, MRI findings, and confirmation of diagnosis were compared and analyzed, and the accuracy of MRI in diagnosing meniscal tears and ACL injuries of the knee was analyzed. Results: The mean ACL angle was (98.0 ± 5.4) in the MRI group and (118.0 ± 6.8) in the arthroscopic group, the difference between the two groups was statistically significant P < .05. The mean L/H value of the ACL was (2.12 ± 0.38) in the MRI group and (1.81 ± 0.19) in the arthroscopic group, which was statistically different between the two groups (P < .05). Among the patients, 68 meniscal injuries were found in the MRI examination, including 45 cases of knee meniscal tears and 23 cases of anterior cruciate ligament injuries. The sensitivity, specificity, positive and negative predictive values, agreement rate, kappa value, and Youden index of MRI in diagnosing meniscal tears and ACL injuries were all high. Conclusions: In terms of sensitivity and accuracy, MRI is an excellent imaging technique for the diagnosis of meniscal tears and anterior cruciate ligament injuries of the knee.

Development and Analysis of Mouse Medial Meniscus Posterior Root Tear Model.

Medial meniscus posterior root tears (MMPRT) are often associated with osteoarthritis (OA) progression and subchondral bone insufficiency fractures. This study aimed to develop the first MMPRT mouse model. The MMPRT model was created by sectioning the medial meniscus posterior root of 12-week-old CL57BL/6J male mice under stereomicroscopic observation. The sham operation and the destabilization of the medial meniscus (DMM) model groups were also created. OA progression and subchondral bone changes were evaluated histologically using the Osteoarthritis Research Society International (OARSI) subchondral bone scoring system at 2, 4, 8, and 12 weeks after surgery. Microcomputed tomography (µCT) was performed to evaluate the presence of insufficient fractures. OA progression and medial meniscus extrusion were observed in the MMPRT and DMM models 12 weeks after surgery. OA progressed in both models during the time course, without a significant difference in the OARSI score between the two groups. The subchondral bone score was significantly higher at 12 weeks than at 2 and 4 weeks in the MMPRT group, while no significant difference was found between the two groups. In the µCT analysis, destruction of the medial tibial plateau was observed in 4/40 knees, while none were observed in the DMM group. Of the four knees, destruction of the medial femoral condyle was also observed in three knees. Characteristic pathological changes were observed in the mouse MMPRT model. The mouse MMPRT model may be useful for investigating pathological changes after MMPRT.

Increased Time to Surgery After Anterior Cruciate Ligament Tear in Female Patients Results in Greater Risk of Medial Meniscus Tear: A Study of 489 Female Patients.

PURPOSE: This study assessed the incidence of meniscal tears in anterior cruciate ligament (ACL)-deficient knees, considering the time between injury and reconstruction in a large sample of female patients. Furthermore, we evaluated whether the rate of meniscal repair or meniscectomy was affected by age and body mass index (BMI). METHODS: The medical records of 489 patients who underwent ACL-reconstructive surgery between January 2011 and April 2021 were analyzed to collect data on the prevalence of meniscal tears, surgical timing, patient age, and BMI. Logistic regression was performed to estimate the association between the prevalence of meniscal tears and the independent variables of surgical timing, age, and BMI. RESULTS: Between 24 and 60 months after their injury, female patients showed a statistically significant increase in the presence of associated meniscal lesions when compared with ACL reconstruction performed earlier (odds ratio [OR] of 3.11; 95% 1.06-9.10 confidence interval [CI]), especially for medial meniscal tears, with an OR of 1.94 (95% CI 1.23-3.05, P = .004) between 12 and 24 months. There is a statistically significant difference after 12 months in the rate of meniscal suturing for medial meniscus tears (OR 3.30; CI 1.37-7.91 P = .007). Increasing age was associated with a greater prevalence of meniscal tears up to 30-50 years, but there was no clear association between BMI and associated lesions other than a greater rate of meniscectomies. CONCLUSIONS: In female patients who experienced an ACL injury, a delay in surgery greater than 12 months is associated with a gradual increase in the risk of nonrepairable medial meniscal tear; this risk becomes statistically significant after 24 months. A high BMI does not seem to have relevance in the onset of associated lesions in women but results in a greater rate of meniscectomies compared with meniscal sutures, whereas age between 30 and 50 years is associated with a greater risk of associated injuries. LEVEL OF EVIDENCE: III, retrospective comparative prognostic trial.

Isolated Posterior Lateral Meniscofemoral Ligament Tears Show Greater Meniscal Extrusion in Knee Extension, and Isolated Posterior Lateral Meniscal Root Tears Show Greater Meniscal Extrusion at 30° Using Ultrasound: A Cadaveric Study.

PURPOSE: To quantify the effects that posterior meniscofemoral ligament (pMFL) lesions have on lateral meniscal extrusion (ME) both with and without concomitant posterior lateral meniscal root (PLMR) tears and describe how lateral ME varied along the length of the lateral meniscus. METHODS: Ultrasonography was used to measure ME of human cadaveric knees (n = 10) under the following conditions: control, isolated pMFL sectioning, isolated PLMR sectioning, pMFL+PLMR sectioning, and PLMR repair. ME was measured anterior to the fibular collateral ligament (FCL), at the FCL, and posterior to the FCL in both unloaded and axially loaded states at 0° and 30° of flexion. RESULTS: Isolated and combined pMFL and PLMR sectioning consistently demonstrated significantly greater ME when measured posterior to the FCL compared with other image locations. Isolated pMFL tears demonstrated greater ME at 0° compared with 30° of flexion (P < .05), whereas isolated PLMR tears demonstrated greater ME at 30° compared with 0° of flexion (P < .001). All specimens with isolated PLMR deficiencies demonstrated greater than 2 mm of ME at 30° flexion, whereas only 20% of specimens did so at 0°. When the pMFL was sectioned following an isolated PLMR tear, there was a significant increase in ME at 0° (P < .001). PLMR repair after combined sectioning restored ME to levels similar to that of controls in all specimens when measured at and posterior to the FCL (P < .001). CONCLUSIONS: The pMFL protects against ME primarily in full extension, whereas the presence of ME in the setting of PLMR injuries may be better appreciated in knee flexion. With combined tears, isolated repair of the PLMR can restore near-native meniscus position. CLINICAL RELEVANCE: The stabilizing properties of intact pMFL may mask the presentation of PLMR tears and delay appropriate management. Additionally, the MFL is not routinely assessed during arthroscopy due to difficult visualization and access. Understanding the ME pattern of these pathologies in isolation and combination may improve detection rates so that the source of patients' symptoms can be addressed to satisfaction.

Delaying ACL reconstruction is associated with increased rates of medial meniscal tear.

PURPOSE: The aim of this study was to evaluate the relationship between the time from injury to ACL reconstruction (ACLR) and the rate as well as repairability of meniscal tears. Secondary aims were to evaluate the relationship between meniscal injury and Tegner Activity Scale, age, BMI, and gender. METHODS: Between 2012 and 2022, 1,840 consecutive ACLRs were performed. A total of 1,317 ACLRs were included with a mean patient age of 31.2 years ± 10.5 [16-60]. Meniscal tear was assessed during arthroscopy using the ISAKOS classification. Time from injury to ACLR, Tegner Activity Scale, age, BMI and gender were analysed in uni- and then in multivariate analyses. Patients were divided into four groups according to the time from injury to surgery: < 3 months (427; 32%), 3-6 months (388; 29%), 6-12 months (248; 19%) and > 12 months (254; 19%). RESULTS: Delaying ACLR > 12 months significantly increased the rate of medial meniscal (MM) injury (OR 1.14; p < 0.001). No correlation was found between a 3- or 6-month time from injury to surgery and MM tear. Performing ACLR > 3, 6, or 12 months after injury did not significantly increase the rate of lateral meniscal (LM) injury. Increasing Tegner activity scale was significantly associated with a lower rate of MM injury (OR 0.90; p = 0.020). An age > 30 years (OR 1.07; p = 0.025) and male gender (OR 1.13; p < 0.0001) was also associated with an increased rate of MM injury. Age > 30 years decreased the rate of MM repair (OR 0.85; p < 0.001). Male gender increased the rate of LM tear (OR 1.10; p = 0.001). CONCLUSION: Performing ACLR more than 12 months after injury was associated with increased rates of MM injury but not with lower rates of repairable lesions. An increased pre-injury Tegner activity score was associated with a decreased rate of MM tear. Age > 30 years was associated with an increased rate of MM tear with concomitant ACL injury and a decreased rate of repairability of MM tear. ACLR should be performed within 12 months from injury to prevent from the risk of MM injury. LEVEL OF EVIDENCE: Level III.

High prevalence of meniscal ramp lesions in anterior cruciate ligament injuries.

PURPOSE: To evaluate the prevalence of and factors associated with meniscal ramp lesions on magnetic resonance imaging (MRI) in patients with anterior cruciate ligament (ACL) injuries. METHODS: Data from the Natural Corollaries and Recovery after ACL injury multicentre longitudinal cohort study (NACOX) were analysed. Only patients who underwent MRI were included in this study. All MRI scans were reviewed by an orthopaedic knee surgeon and a musculoskeletal radiologist. The patients were divided into two groups, those with and without ramp lesions according to MRI findings. Univariable and stepwise forward multiple logistic regression analyses were used to evaluate patient characteristics (age, gender, body mass index, pre-injury Tegner activity level, activity at injury) and concomitant injuries on MRI (lateral meniscus, medial collateral ligament [MCL], isolated deep MCL, lateral collateral ligament, pivot-shift-type bone bruising, posteromedial tibial [PMT] bone bruising, medial femoral condyle bone bruising, lateral femoral condyle [LFC] impaction and a Segond fracture) associated with the presence of meniscal ramp lesions. RESULTS: A total of 253 patients (52.2% males) with a mean age of 25.4 ± 7.1 years were included. The overall prevalence of meniscal ramp lesions was 39.5% (100/253). Univariate analyses showed that contact sports at ACL injury, pivot-shift-type bone bruising, PMT bone bruising, LFC impaction and the presence of a Segond fracture increased the odds of having a meniscal ramp lesion. Stepwise forward multiple logistic regression analysis revealed that the presence of a meniscal ramp lesion was associated with contact sports at ACL injury [odds ratio (OR) 2.50; 95% confidence intervals (CI) 1.32-4.72; P = 0.005], pivot-shift-type bone bruising (OR 1.29; 95% CI 1.01-1.67; P = 0.04), PMT bone bruising (OR 4.62; 95% CI 2.61-8.19; P < 0.001) and the presence of a Segond fracture (OR 4.38; 95% CI 1.40-13.68; P = 0.001). CONCLUSION: The overall prevalence of meniscal ramp lesions in patients with ACL injuries was high (39.5%). Contact sports at ACL injury, pivot-shift-type bone bruising, PMT bone bruising and the presence of a Segond fracture on MRI were associated with meniscal ramp lesions. Given their high prevalence, meniscal ramp lesions should be systematically searched for on MRI in patients with ACL injuries. Knowledge of the factors associated with meniscal ramp lesions may facilitate their diagnosis, raising surgeons' and radiologists' suspicion of these tears. LEVEL OF EVIDENCE: III.

Intrameniscal degeneration and meniscotibial ligament loosening are associated factors with meniscal extrusion of symptomatic discoid lateral meniscus.

PURPOSE: This study aimed to compare the amount of extrusion of the discoid lateral meniscus (DLM), which was symptomatic and required surgery, with normal meniscuses and asymptomatic DLMs and examine factors associated with the extrusion of symptomatic DLM. METHODS: Medical records of participants with DLM or normal lateral meniscus (LM) were retrospectively reviewed using magnetic resonance imaging (MRI). DLM cases were divided into symptomatic and asymptomatic groups. The midbody meniscal extrusion was measured using mid-coronal MRI. The association between meniscal extrusion and MRI findings, including the meniscofemoral ligament, meniscotibial ligament (MTL), intrameniscal signal intensity of the peripheral rim, meniscal shift, and skeletal maturity, was evaluated. RESULTS: Eighty-six knees with DLM (63 symptomatic) were included. The control group included 31 patients. The symptomatic group showed significantly greater meniscal extrusion (mean ± standard deviation symptomatic DLM: 1.0 ± 1.1 mm, asymptomatic DLM: 0.1 ± 0.4 mm, and normal LM: 0.3 ± 0.6 mm, P < 0.001) and had a significantly higher incidence of MTL loosening (P = 0.02) and intrameniscal signal (P < 0.001) than the other two groups. In the symptomatic group, multivariable linear regression analysis showed that MTL loosening [ß = 1.45, 95% confidence interval (CI) 1.03-1.86, P < 0.001] and intrameniscal signal (ß = 0.49, 95% CI 0.09-0.90, P = 0.002) were independent associated factors. CONCLUSIONS: LM extrusion was significantly more common in patients with symptomatic DLM than in those with asymptomatic DLM or a normal LM. MTL loosening and intrameniscal high-signal intensity on MRI were independently associated with meniscal extrusion. These findings help explain the pathogenesis and diagnosis of symptomatic DLM. LEVEL OF EVIDENCE: III.

Steep posterior slope of the medial tibial plateau and anterior cruciate ligament degeneration contribute to medial meniscus posterior root tears in young patients.

PURPOSE: Medial meniscus posterior root tears (MMPRTs) occur most frequently in middle-aged and older adults. However, this serious condition can also occur in younger patients. The purpose of this study was to compare anterior cruciate ligament (ACL) degeneration and sagittal medial tibial slope in young adults with and without MMPRT. METHODS: Eighteen healthy volunteers, 18 young patients (20-49 years of age), and 30 middle-aged and older patients (50-70 years of age) with MMPRT repair were included in the study. Sex, body mass index (BMI), femorotibial angle, ACL degeneration, and medial tibial slope angle were compared among the groups. ACL degeneration and medial tibial slope angle were assessed using magnetic resonance imaging. RESULTS: In the healthy volunteer group, the young patient group, and the older patient group, the medial tibial slopes were 3.5° ± 1.4°, 6.1° ± 2.7°, and 7.2° ± 1.9°, respectively, and the ACL degeneration rates were 5.6%, 38.9%, and 43.3%, respectively. Young patients with MMPRT had significantly steeper medial tibial slopes and ACL degeneration compared to those of the healthy volunteers (P < 0.05). The parameters of young patients were similar to those of older patients with MMPRT. In the multivariate logistic regression analysis, BMI, medial tibial slope, and ACL degeneration were significantly associated with MMPRT in young patients. CONCLUSION: BMI, steep medial tibial slope, and ACL degeneration contribute to MMPRT development in younger patients. LEVEL OF EVIDENCE: Level III.

Lateral-medial asymmetry of posterior tibial slope and small lateral tibial plateau articular surface depth are morphological factors of lateral meniscus posterior root tears in ACL-injured patients.

PURPOSE: To investigate whether knee morphological features, patient characteristics, and intraoperative findings are associated with a lateral meniscus (LM) posterior root tear (LMPRT) in anterior cruciate ligament (ACL) injuries with the integrated data from two academic centres. METHODS: This retrospective study used registry data acquired prospectively at two academic centres. Patients with ACL reconstruction (ACLR) with LMPRT and no other LM injury were selected (LMPRT group) from each database. The control group included patients who underwent ACLR without LM tears. Patients were matched to the LMPRT group according to age and gender (1:1). Morphological factors evaluated on preoperative magnetic resonance image scans included lateral femoral condyle (LFC) anterior-posterior diameter, height, and depth; lateral tibial plateau (LTP) articular surface (AS) depth and sagittal plane depth; and lateral and medial posterior tibial slopes (PTSs). LFC height and depth ratios, LTP AS depth and sagittal plane depth ratios, and lateral-to-medial slope asymmetry were computed from previous measurements. Patient characteristics and intraoperative findings were extracted and compared between both groups. RESULTS: The study included 252 patients (126 in each group). The lateral-medial asymmetry of PTS was greater in the LMPRT group (1.2° vs 0.3°, p < 0.05), and the LTP AS depth was smaller in the LMPRT group (31.4 mm vs 33.2 mm, p < 0.01). There were no differences in LFC morphology between the control and LMPRT groups. Pivot shift grade (p < 0.05), percentage of complete ACL tears (p < 0.05), and medial meniscus ramp lesions (p < 0.05) were significantly higher in the LMPRT group. CONCLUSION: LMPRT was associated with significantly increased lateral-medial asymmetry of PTS and significantly smaller LTP AS depth. LMPRT was also associated with an increase in the preoperative pivot shift grade and the presence of a medial meniscus ramp lesion. These morphological characteristics are rather simple to measure and would serve as helpful indicators to preoperatively detect LMPRT, which is frequently challenging to diagnose preoperatively. LEVEL OF EVIDENCE: Level III.

Higher Grit Scores Are Associated With Earlier Increases in Knee Flexion Following Anterior Cruciate Ligament Reconstruction With Meniscus Repair in Pediatric Patients.

BACKGROUND: The Grit Scale is used to measure grit, defined by Duckworth and colleagues as the disposition to show perseverance and passion for long-term goals. It has been shown that psychological factors like motivation, coachability, and coping with adversity are correlated with faster readiness for return to sport (RTS) in patients undergoing anterior cruciate ligament reconstruction (ACLR). This study investigates the association between pediatric patients' baseline grit scores and; preoperative Patient-reported Outcomes Measurement Information System (PROMIS) Pain scores and the recovery of range of motion (ROM) after ACLR. The investigators hypothesized that higher preoperative grit scores would predict lower preoperative pain scores and earlier return of knee ROM in patients undergoing ACLR. METHODS: This is a retrospective cohort study. Pediatric patients who underwent primary ACLR were assigned the pediatric Grit Scale. Patients were subdivided by meniscal procedures due to differences in postoperative protocols. ACLR alone or with meniscectomy (ACLR ± meniscectomy) were grouped together and ACLR with meniscal repair (ACLR + meniscus repair) represented the other cohort. Patients above the 50th grit percentile were considered "high grit". Patients below the 50th percentile were considered "low grit". Baseline PROMIS pain intensity and interference were collected. ROM was compared by grit cohort using the Mann-Whitney U test with a significance threshold of P ≤ 0.05. RESULTS: A total of 58 patients undergoing ACLR were analyzed: 20 ACLR ± meniscectomy and 38 ACLR + meniscus repair. The mean age was 15.0 ± 2.1 years with 41.4% of participants identifying as females. No significant difference was noted between baseline PROMIS pain intensity and interference and grit score ( P = 0.82, P = 0.91, respectively). Three months postoperatively, for those in the ACLR + meniscus repair cohort, low grit ROM was 130 degrees (interquartile range = 10 degrees), whereas high grit ROM was 135 degrees (interquartile range = 8 degrees) ( P = 0.006). CONCLUSIONS: This study found no differences in pain scores at presentation between grit cohorts but found that patients with grit scores below the 50th percentile undergoing ACLR + meniscus repair have 5 degrees less total ROM at 3 months compared with those with high grit scores. Quicker ROM recovery in patients with high grit may be a leading indicator of these patients' likelihood to achieve other postoperative milestones and meet criteria for RTS more quickly; the relationship between grit and readiness for RTS should be further investigated. LEVEL OF EVIDENCE: Level IV; retrospective cohort study.

Evaluation and Treatment of Knee Pain: A Review.

Importance: Approximately 5% of all primary care visits in adults are related to knee pain. Osteoarthritis (OA), patellofemoral pain, and meniscal tears are among the most common causes of knee pain. Observations: Knee OA, affecting an estimated 654 million people worldwide, is the most likely diagnosis of knee pain in patients aged 45 years or older who present with activity-related knee joint pain with no or less than 30 minutes of morning stiffness (95% sensitivity; 69% specificity). Patellofemoral pain typically affects people younger than 40 years who are physically active and has a lifetime prevalence of approximately 25%. The presence of anterior knee pain during a squat is approximately 91% sensitive and 50% specific for patellofemoral pain. Meniscal tears affect an estimated 12% of the adult population and can occur following acute trauma (eg, twisting injury) in people younger than 40 years. Alternatively, a meniscal tear may be a degenerative condition present in patients with knee OA who are aged 40 years or older. The McMurray test, consisting of concurrent knee rotation (internal or external to test lateral or medial meniscus, respectively) and extension (61% sensitivity; 84% specificity), and joint line tenderness (83% sensitivity; 83% specificity) assist diagnosis of meniscal tears. Radiographic imaging of all patients with possible knee OA is not recommended. First-line management of OA comprises exercise therapy, weight loss (if overweight), education, and self-management programs to empower patients to better manage their condition. Surgical referral for knee joint replacement can be considered for patients with end-stage OA (ie, no or minimal joint space with inability to cope with pain) after using all appropriate conservative options. For patellofemoral pain, hip and knee strengthening exercises in combination with foot orthoses or patellar taping are recommended, with no indication for surgery. Conservative management (exercise therapy for 4-6 weeks) is also appropriate for most meniscal tears. For severe traumatic (eg, bucket-handle) tears, consisting of displaced meniscal tissue, surgery is likely required. For degenerative meniscal tears, exercise therapy is first-line treatment; surgery is not indicated even in the presence of mechanical symptoms (eg, locking, catching). Conclusions and Relevance: Knee OA, patellofemoral pain, and meniscal tears are common causes of knee pain, can be diagnosed clinically, and can be associated with significant disability. First-line treatment for each condition consists of conservative management, with a focus on exercise, education, and self-management.

Combined Medial And Lateral Bucket Handle Meniscus Tears With Associated Complete Anterior Cruciate Ligament Tear: A Case Report.

The majority of meniscal tears in bucket handles are associated with anterior cruciate ligament (ACL) impairment. Its a rare condition which is rarely encountered when the meniscus has a bucket handle on both sides of the compartment. Here we present the case of a 28-year- old male cricket player with a total ACL rupture, a double Posterior Cruciate ligament (PCL) sign on MRI (Magnetic Resonance Imaging), an uncommon occurrence of a complex bucket handle rupture of the medial meniscus with a double PCL sign. It was a complete ACL tear and displaced bucket handle medial meniscus that was also visible on the magnetic resonance imaging. In this report, double PCL sign was shown on MRI and that was confirmed during the arthroscopic procedure.

Posterolateral tibial plateau bone bruises in anterior cruciate ligament (ACL) injuries and its association with lateral meniscal injuries.

INTRODUCTION: This study examined the prevalence of posterolateral tibial bone bruising in isolated anterior cruciate ligament (ACL) injuries, prevalence of meniscal injuries in ACL injuries, as well as the association between posterolateral tibial bone bruising and lateral meniscal tears among those with ACL injury undergoing Primary ACL Reconstruction. MATERIALS AND METHODS: Retrospective data on 130 patients who underwent primary ACL reconstructions was analysed. Their preoperative magnetic resonance images (MRI) were reviewed for the presence of posterolateral tibial bone bruise. The presence of meniscal injuries was recorded based on the arthroscopic findings from the operative records. RESULTS: 95 patients were recruited into the study. The prevalence of posterolateral bone bruise in this study was 41%. There was a statistically significant difference when comparing the prevalence of bone bruising to the time of injury to MRI (p<0.001). The prevalence of an injury to at least one meniscus at the time of ACLR surgery was 83.2%. The prevalence of lateral meniscus injuries in patients with bone bruise was found to be 53.9%. The crude odds ratio of a patient having a lateral meniscal tear in the presence of bone bruising was 1.56 (0.68, 3.54). This figure was even higher when it was adjusted for time to MRI and was 2.06 (0.77, 5.46). CONCLUSION: Prevalence of posterolateral tibial bone bruising in our study was 41%, and the prevalence of meniscal injury to either meniscus at the point of surgery was 83.2%, out of which the lateral meniscus tears were identified during ACLR surgery in 47.3% of the patients. We found there was no association between posterolateral tibial bone bruising to sex, age and mode of injury, but was sensitive to the interval between time of injury and MRI. The overall prevalence of lateral meniscal tears was higher in patients with posterolateral bone bruising but was not statistically significant with a P value of 0.31; however, the Crude odd ratio was 1.56 (0.68, 3.54) and was higher when adjusted to time of injury to MRI 2.06 (0.77, 5.46). We suggest for MRI to be done as soon as possible after injury in regard to bone bruising identification. We should be vigilant to look for lateral meniscal tears and anticipate for its repair in ACL injuries, especially so when we identify posterolateral tibial bruising on the preoperative MRI.

The difference in joint instability affects the onset of cartilage degeneration or subchondral bone changes.

OBJECTIVE: It has been debated whether the onset of knee osteoarthritis is initiated in cartilage or subchondral bone. The purpose of this study was to clarify the effects of increasing or decreasing joint instability on cartilage degeneration and subchondral bone changes in knee OA by comparing different models of joint instability. DESIGN: We used the anterior cruciate ligament transection (ACL-T) model and the destabilization of the medial meniscus (DMM) model. In addition, we created a controlled abnormal tibial translation (CATT) model and a controlled abnormal tibial rotation (CATR) model. We performed joint instability analysis, micro-computed tomography analysis, histological and immunohistological analysis in 4 and 6 weeks. RESULTS: The CATT group suppressed joint instability in the ACL-T group (6 weeks; P = 0.032), and the CATR group suppressed joint instability in the DMM group (6 weeks; P = 0.032). Chondrocyte hypertrophy in the ACL-T and DMM groups was increased compared to the Sham group (6 weeks; [ACL-T vs Sham], P = 0.002, 95%CI [5.983-33.025]; [DMM vs Sham], P = 0.022, 95%CI [1.691-28.733]). In the subchondral bone, the BV/TV in the DMM and CATR groups was increased compared to the ACL-T and CATT groups (6 weeks; [DMM vs ACL-T], P = 0.002, 95%CI [7.404-37.582]; [DMM vs CATT], P = 0.014, 95%CI [2.881-33.059]; [CATR vs ACL-T], P = 0.006, 95%CI [4.615-34.793]; [CATR vs CATT], P = 0.048, 95%CI [0.092-30.270]). CONCLUSIONS: This study showed that joint instability promotes chondrocyte hypertrophy, but subchondral bone changes were influenced by differences in ACL and meniscus function.

The prevalence and parameters of fabella and its association with medial meniscal tear in China: a retrospective study of 1011 knees.

BACKGROUND: Fabella is a sesamoid bone of knee that has potential biomechanical function. We aimed to examine the fabellar prevalence and parameters in Chinese population and test the hypothesis that fabellar presence and morphology were associated with meniscus tear or ligament injury. METHODS: A total of 1011 knee magnetic resonance imaging scans from 979 patients with knee pain were analyzed retrospectively. The exclusion criteria are postsurgical scans, difficulty in fabella discrimination, conditions not suitable for measurement, and unsatisfied image. The fabellar presence and its parameters (length, width and thickness) were documented. The association between fabellar presence and meniscus tear or ligament injury were assessed by chi-square test, in all knees and subgroups (age, gender, side, lesion part). The correlation of fabellar presence and parameters with advancing age was assessed by Spearman correlation analysis. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to investigate whether factors related with meniscus tear or ligament injury. Diagnostic performance of risk factors was assessed by receiver operating characteristic (ROC) analysis. RESULTS: The overall prevalence of fabellae was 39.8% (402/1011 knees) and increased with the increasing age (r = 0.237, P < 0.001). The size of the fabellae differed according to genders, age, and presence of articulating grooves. Fabella presented more often in knees with medial meniscus (MM) tears (66.7% vs 33.8%; P < 0.001) with a multivariate OR of 2.960 (95% CI, 1.853-3.903). The association remained in all tear parts (anterior, middle, and posterior), and in younger (age < 50 years) and older patients (age ≥ 50 years). Age, fabellar length, width, length/thickness ratio and width/thickness ratio yielded an area under the ROC curve (AUC) of 0.604-0.766 to predict an MM tear. In combination with age, fabellar width and length/thickness ratio, the AUC was improved 0.791 (95% CI, 0.744-0.837), with a sensitivity of 73.0% and a specificity of 74.6%. CONCLUSION: The presence of fabellae, increased fabellar length and width as well as flatter fabellar morphology, are significantly associated with an increased risk for MM tear. These findings might aid clinicians in identifying patients at risk for a MM tear and informing them.

Isolated Arthroscopic Partial Meniscectomy Is More Effective at Improving Meniscal Symptoms in Comparison With Mechanical Symptoms in Patients With Concomitant Untreated Chondral Lesions.

PURPOSE: To rank Knee Injury and Osteoarthritis Outcome Score (KOOS) questions from most to least improvement after arthroscopic partial meniscectomy (APM) and compare improvement of meniscal versus mechanical symptoms. METHODS: A secondary analysis of the Chondral Lesions and Meniscus Procedures (ChAMP) Trial was performed. Inclusion criteria were age 30 years or older with degenerative meniscal tear failing nonoperative management, with or without associated unstable chondral lesions. No chondral debridement was performed. Responses to the 42 KOOS questions ranged from 0 (extreme problems) to 4 (no problems), and were answered preoperatively and at 1 year after isolated APM. The 1-year mean change, or delta (Δ), was calculated for each KOOS question and the Δ for meniscal and mechanical symptoms were statistically compared. RESULTS: Greatest improvement in 135 eligible patients was observed for questions about (1) awareness of knee problems (Δ = 1.93, standard deviation [SD] = 1.38), (2) frequency of knee pain (Δ = 1.93, SD = 1.29), (3) degree of difficulty while twisting/pivoting on the injured knee (Δ = 1.88, SD = 1.13), (4) degree of difficulty while running (Δ = 1.67, SD = 1.30), and (5) being troubled by lack of confidence in the knee (Δ = 21.67, SD = 1.11). Least improvement was observed for questions about: (1) degree of difficulty while getting on/off the toilet (Δ = 0.94, SD = 0.96), (2) feel grinding or hear clicking when the knee moves (Δ= 0.90, SD = 1.25), 3) degree of difficulty while getting in/out of the bath (Δ= 0.88, SD = 1.00), (4) knee catches/hangs up during movement (Δ= 0.80, SD = 1.09), and (5) the ability to straighten the knee fully (Δ= 0.54, 1.44). There was greater improvement for the KOOS questions pertaining to meniscal versus mechanical symptoms (P < .00001). CONCLUSIONS: KOOS symptoms as reported by subjects' responses to the questions pertaining to the frequency of knee pain, twisting/pivoting, running, squatting, and jumping showed the most improvement 1 year after isolated APM, whereas those relating to mechanical symptoms improved the least. Focusing on meniscal rather than mechanical symptoms may help surgeons better identify patients expected to benefit from APM. LEVEL OF EVIDENCE: IV, retrospective analysis of prospectively collected data.

Editorial Commentary: Arthroscopic Partial Meniscectomy Outcomes Are Worse in Patients With Concomitant Pathology.

Arthroscopic debridement for degenerative joint disease has not been shown to be beneficial, and initial nonoperative management is now recommended for degenerative meniscal tears. Indications for arthroscopic partial meniscectomy (APM) are traumatic tears with a clear history of mechanical symptoms, such as locking and catching, with joint-line pain or acute onset of symptoms that have failed nonsurgical treatment. Predictors of dissatisfaction with APM include female sex, obesity, and lateral meniscal tears. Beyond such demographic factors, concomitant joint pathology negatively affects outcomes of APM because a large majority of patients without radiographic osteoarthritis (OA) have evidence of concomitant tissue changes considered to be associated with OA including chondral damage, subchondral bone changes, signs of inflammation or ligament pathology. Particularly relevant seem to be chondral lesions radiologists would label as "delaminating," which are those a surgeon might call an "impending loose bodies." Cartilage repair surgery may be indicated in these cases.

Increased Risk of Concomitant Meniscal Injuries in Adolescents With Elevated Body Mass Index After Anterior Cruciate Ligament Tear: A Systematic Review.

PURPOSE: To investigate existing studies examining the association between body mass index (BMI) and outcomes of anterior cruciate ligament reconstruction (ACLR) in adolescent patients. METHODS: A literature search was conducted on PubMed and Embase. Studies examining associations between BMI and outcomes after ACLR in adolescents were included. Quality assessment was performed. Data on patient age, sex, study design, time of follow-up, sample size, graft type, concomitant injuries (meniscal injury, surgical procedures), clinical outcomes (revision ACLR, postoperative weight gain, post-traumatic osteoarthritis [PTOA], range of motion [ROM]), and functional outcome (muscle strength) were extracted. RESULTS: Eleven papers of Levels II-IV evidence were included. Five studies found positive correlations between BMI and risk of concomitant meniscal injuries. Two of them reported young patients with elevated BMI having 1.6 times greater odds of requiring meniscectomy (P < .01) and 1.031 times greater odds of requiring concomitant surgeries (P = .011). One study showed significant positive association of postoperative weight gain by time (r = 0.28, P < .01), with smaller increase in the overweight and obese groups compared with the normal-weight group. One study demonstrated greater cartilage breakdown in young patients with overweight and obesity postsurgery, contributing to PTOA (r = 0.42, P = .009). There was no clinically important difference in postoperative ROM and muscle strength. Four studies reviewed the association between BMI and revision ACLR risk, but results were heterogeneous and a firm conclusion cannot be drawn. CONCLUSIONS: Adolescents with elevated BMI are more likely to have concomitant meniscal injuries and surgical procedures after ACL tear. There is some weak evidence of the association of elevated BMI with PTOA and slight postoperative weight gain post-ACLR. There may not be any clinically significant association of obesity with post-operative muscle strength and ROM, and current studies are inconclusive regarding the impact of BMI on revision ACLR risk. LEVEL OF EVIDENCE: Level IV, systematic review of Level II-IV studies.

Increased Posterior Tibial Slope and Meniscal Slope Could Be Risk Factors for Meniscal Injuries: A Systematic Review.

PURPOSE: The purpose of this systematic review was to summarize the available evidence and examine the relation between the posterior tibial slope (PTS) and meniscal slope (MS) and the incidence of meniscal injury. METHODS: PubMed, Embase, the Cochrane Central Register of Controlled Trials, and Web of Science were searched from inception to February 23, 2021. Cohort studies investigating the association between PTS or MS and the risk of meniscal injury were included. Two authors independently conducted the literature search, data extraction, and quality assessment. RESULTS: Sixteen studies with a total of 2,670 patients were included. For meniscal injury with an anterior cruciate ligament tear, the lateral PTS in the lateral meniscal root tear group (range, 8.0°-12.6°) was significantly higher than that in the control group (range, 4.0°-10.7°). Furthermore, there appeared to be a relation between a greater medial MS and the presence of a ramp lesion (range, 2.6°-6.7° for ramp lesion vs 2.0°-5.1° for control). For degenerative meniscal injury, the medial PTS in the medial meniscal posterior root tear group (range, 6.15°-10.4°) was significantly greater than that in the control group (range, 4.0°-9.8°). CONCLUSIONS: On the basis of the available evidence, for meniscal injury with an anterior cruciate ligament tear, an increased lateral PTS was associated with a higher risk of lateral meniscal tears and lateral meniscal posterior root tears. Furthermore, there appeared to be a relation between an increased medial MS and a higher risk of ramp lesions. For degenerative meniscal injury, most of the included studies showed that a larger medial PTS could increase the risk of medial meniscal tears and medial meniscal posterior root tears. LEVEL OF EVIDENCE: Level III, systematic review of Level III studies.