Factors influencing the posterior cruciate ligament buckling phenomenon-a multiple linear regression analysis of bony and soft tissue structures of the knee joint.

PURPOSE: To determine whether posterior cruciate ligament (PCL) buckling (angular change) is associated with anterior cruciate ligament (ACL) status (intact or ruptured), meniscal bone angle (MBA), anterior tibial translation (ATT), body weight, femoral-tibial rotation (FTR), posterior tibial slope (PTS), PCL length and femoral-tibial distance (FTD) and to identify the factors that have the greatest influence. METHODS: All enrolled participants were scanned with a 3.0 T, 8-channel coil MRI system (Magnetom Verio; Siemens). Bone and soft tissue parameters were measured by MIMICS software for each subject and each measured parameter was correlated with PCL buckling phenomena. The correlated and statistically significant parameters were then analyzed by multiple linear regression to determine the magnitude of the effect of the different parameters on the PCL buckling phenomenon. RESULTS: A total of 116 subjects (50 ACL ruptured and 66 age, weight and height matched volunteers with uninjured knees) were enrolled. Among all measured parameters, there were 8 parameters that correlated with PCL angle (PCLA), of which ACL status had the strongest correlation with PCLA (r = - 0.67, p = < 0.001); and 7 parameters that correlated with PCL-posterior femoral cortex angle (PCL-PCA), of which ATT had the strongest correlation with PCL-PCA (r = 0.69, p = < 0.001). PCLIA was not significantly correlated with any of the measured parameters. Multiple linear regression analyses revealed four parameters can explain PCLA, of which ACL status had the strongest effect on PCLA (absolute value of standardized coefficient Beta was 0.508). Three parameters can explain PCL-PCA, of which ATT had the strongest effect on PCLIA (r = 0.69, p = < 0.001), ATT has the greatest effect on PCL-PCA (absolute value of normalized coefficient Beta is 0.523). CONCLUSIONS: PCLA may be a simple and easily reproducible and important supplement for the diagnosis of ACL injury; PCL-PCA is a simple and easily reproducible and important complementary tool for the detection of ATT. The use of PCLA is more recommended to aid in the diagnosis of ACL injury.

Decreased Posterior Tibial Slope and Its Association With Pediatric Posterior Cruciate Ligament Injury.

BACKGROUND: Recent adult studies have demonstrated that decreased posterior tibial slope angle (PTSA) may be a risk factor for posterior cruciate ligament (PCL) injury. However, there is no study investigating this phenomenon in a pediatric population. Understanding risk factors for PCL injuries among a pediatric population is important given the recent rise in athletic competition/specialization and sports-related injuries. HYPOTHESIS/PURPOSE: The purpose of this study was to compare PTSA between pediatric patients sustaining a primary PCL tear compared with age- and sex-matched controls. It was hypothesized that pediatric patients sustaining a PCL tear would have a decreased PTSA compared with controls, with decreased PTSA being associated with higher odds of PCL injury. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: The records of all patients sustaining a PCL injury between 2006 and 2021 at a level 1 pediatric trauma center were reviewed. Patients aged ≤18 years with magnetic resonance imaging-confirmed PCL tear were included. Excluded were patients with concomitant anterior cruciate ligament tears, previous PCL reconstruction, or previous coronal plane realignment. A control cohort, with their ligament shown as intact on magnetic resonance imaging scans, was matched based on age and sex. PTSA was measured on lateral radiographs of the injured knee or tibia. The mean PTSA was compared between cohorts, and odds ratios were calculated based on the normal slope range (7°-10°) described in the literature, an upper range (>10°), and a lower range (<7°). Inter- and intrarater reliability were determined via calculation of an intraclass correlation coefficient. RESULTS: Of the 98 patients who sustained a PCL injury in this study period, 59 (60%) met inclusion criteria, and 59 healthy knee controls were matched. There were no differences between the cohorts for age (P = .90), sex (P > .99), or body mass index (P = .74). The PCL cohort had a lower mean ± SD PTSA compared with the control group (5.9°± 2.7° vs 7.3°± 4.3°; P = .03). PTSA <7° was associated with a 2.8 (95% CI, 1.3-6.0; P = .01) times risk of PCL tear. Conversely, PTSA >10° was associated with a 0.27 (95% CI, 0.09-0.81; P = .02) times risk of PCL tear. These PTSA measurements demonstrated acceptable intrarater and interrater reliability. CONCLUSION: PTSA <7° was associated with an increased odds of PCL injury, whereas a slope >10° was associated with a decreased odds of PCL injury in a pediatric population. These findings corroborate similar outcomes in adult studies; however, further studies are needed to elucidate PTSA as a risk factor for PCL injury.

The potential of posterior cruciate ligament buckling phenomenon as a sign for partial anterior cruciate ligament tears.

INTRODUCTION: Diagnosis of a partial tear of the anterior cruciate ligament (ACL) can be challenging with physical examination and imaging techniques. Although magnetic resonance imaging (MRI) has high sensitivity and specificity for diagnosing complete ACL tears, its effectiveness may be limited when it is used to diagnose for partial tears. The hypothesis of the present study is that the posterior cruciate ligament (PCL) buckling phenomenon, which is a secondary sign of complete ACL tears on MRI, may be a useful method for diagnosing partial ACL tears. MATERIALS AND METHODS: The data of 239 patients who underwent knee arthroscopy in a single institution between 2016 and 2022 were analyzed retrospectively. Patients were divided into three groups based on the condition of their ligaments: partial tears, complete tears and intact ligaments. To evaluate the buckling phenomenon on sagittal T2-weighted MRI, measurements of the posterior cruciate ligament angle (PCLA) and the posterior cruciate ligament-posterior cortex angle (PCL-PCA) were conducted in each group. Subsequently, the ability of these two measurement methods to distinguish partial tears from the other groups was assessed. RESULTS: Both methods provided significantly different results in all three groups. Partial tears could be distinguished from intact ligaments with 86.8% sensitivity, 89.9% specificity when PCLA < 123.13° and 94.5% sensitivity, 93.2% specificity when PCL-PCA < 23.77°. Partial tears could be distinguished from complete tears with 79.5% sensitivity, 78.4% specificity when PCLA > 113.88° and with 86.1% sensitivity, 85.3% specificity when PCL-PCA > 16.39°. CONCLUSION: The main finding of the present study is that the PCLA and PCL-PCA methods are useful on MRI for diagnosing partial ACL tears. PCLA value between 113°-123° and PCL-PCA value between 16°-24° could indicate a partial ACL tear. With these methods, it is possible to distinguish partial tears from healthy knees and reduce missed diagnoses. In addition, the differentiation of partial and complete tears by these methods may prevent unnecessary surgical interventions. LEVEL OF EVIDENCE: Level III.

A modified anatomical posterior cruciate ligament reconstruction technique using the posterior septum and posterior capsule as landmarks to position the low tibial tunnel.

BACKGROUND: Lowering the exit position of the tibial tunnel can improve the clinical efficacy of posterior cruciate ligament (PCL) reconstruction, however, there is no unified positioning standard. This study aimed to use novel soft tissue landmarks to create a low tunnel. METHODS: A total of 14 human cadaveric knees and 12 patients with PCL injury were included in this study. Firstly, we observed the anatomical position between the PCL, posterior septum, and other tissue, and evaluated the relationship between the center of the low tibial tunnel (SP tunnel) and posterior septum and distal reflection of posterior capsule, and using computed tomography (CT) to evaluate distance between the center of the SP tunnel with bony landmarks. Then, evaluated the blood vessels content in the posterior septum with HE staining. Finally, observed the posterior septum and distal reflection of the posterior capsule under arthroscopy to explore the clinical feasibility of creating a low tibial tunnel, and assessed the risk of surgery by using ultrasound to detect the distance between the popliteal artery and the posterior edge of tibial plateau bone cortex. RESULTS: In all 14 cadaveric specimens, the PCL tibial insertions were located completely within the posterior medial compartment of the knee. The distance between the center of the SP tunnel and the the articular surface of tibial plateau was 9.4 ± 0.4 mm. All SP tunnels retained an intact posterior wall, which was 1.6 ± 0.3 mm from the distal reflection of the posterior capsule. The distances between the center of the SP tunnel and the the articular surface of tibial plateau, the champagne glass drop-off were 9.2 ± 0.4 mm (ICC: 0.932, 95%CI 0.806-0.978) and 1.5 ± 0.2 mm (ICC:0.925, 95%CI 0.788-0.975) in CT image. Compared with the posterior capsule, the posterior septum contained more vascular structures. Last, all 12 patients successfully established low tibial tunnels under arthroscopy, and the distance between the posterior edge of tibial plateau bone cortex and the popliteal artery was 7.8 ± 0.3, 9.4 ± 0.4 and 7.4 ± 0.3 mm at 30°, 60° and 90° flexion angels after filling with water and supporting with shaver in posterior-medial compartment of knee joint. CONCLUSIONS: A modified low tibial tunnel could be established in the PCL anatomical footprint by using the posterior septum and posterior capsule as landmarks.

The use of ultrasonography as an effective screening tool for chronic posterior cruciate ligament injuries.

PURPOSE: We aimed to explore the applicability and validity of ultrasonography for diagnosing chronic posterior cruciate ligament (PCL) injuries. METHODS: PCL thickness was measured at 2 cm proximal to the tibia insertion site. Using the same ultrasonography image, the angle tangent to the PCL from the tibia insertion site was also measured. These data were analyzed by plotting the receiver operating curve (ROC), and the sensitivity and specificity were calculated according to the optimal cut-off point. Ultrasonography data from the PCLinjured knee were compared with those from the contralateral uninjured knee of the same patient. RESULTS: Twelve men and six women, with a mean age of 28.8 ± 14.0 years, were included in this study. The mean time from injury to medical examination was 10.0 ± 6.7 months. The mean thickness of the PCL was 8.1 ± 1.9 mm on the affected side and 5.8 ± 1.2 mm on the uninjured side, with the affected side being significantly thicker. ROC analysis revealed that the optimal cut-off value for the thickness of chronic PCL injuries was 6.5 mm (sensitivity 83.3%, specificity 77.8%, area under the curve [AUC] = 0.87). The optimal cut-off value for the angle was 20° (sensitivity 88.9%, specificity 94.4%, AUC = 0.96). CONCLUSION: Ultrasonography is useful as a screening tool for chronic PCL injuries. The optimal cut-off point was 6.5 mm for thickness and 20° for angle. LEVEL OF EVIDENCE: IV.

Functional and MRI results after a 7.5 year follow-up of 35 single-stage ACL and PCL reconstructions using gracilis and semitendinosus tendon grafts and LARS artificial ligaments.

PURPOSE: The aim of this study was to evaluate the long-term functional and MRI results of 35 patients who underwent bicruciate ligament reconstruction combining an ACL autograft using the gracilis and semitendinosus tendons and double-bundle PCL reconstruction using the LARS artificial ligament. METHODS: The outcomes were measured using the Lysholm score, the Tegner activity level scale and the International Knee Documentation Committee form (IKDC 2000). KT-1000 was used to assess the clinical anterior knee laxity. Radiographs and Magnetic Resonance Imaging (MRI) was used to evaluate osteoarthritis, the continuity and integrity of ACL autograft and LARS. RESULTS: This retrospective study examined 35 patients who underwent single-stage bicruciate ligament reconstruction between May 2005 and January 2017 with a follow-up period ranging from 3 to 15 years (a mean of 7.5 years). The mean Lysholm score was 74, mean IKDC 2000 was 71. There was a statistically significant difference with a higher Lysholm score (78.9) in early versus delayed surgical intervention (p = 0.023). Using the Kellgren Lawrence osteoarthritis classification system, radiographic findings showed stage II or III in 83% of the sample population. The MRI results revealed a rupture rate of 22% of the anterior autografted ligament and 28% of the posterior LARS artificial ligament. However, there were no long-term artificial ligament-induced complications. There was no correlation between artificial ligament rupture and poor functional results (Lysholm < 65). CONCLUSION: The results of this study with a mean follow-up of 7.5 years show satisfactory functional scores considering the initial trauma. It seems reasonable to propose early surgical treatment with double reconstruction of the cruciate ligaments within the first 21 days of the trauma. Post-traumatic osteoarthritis is inevitable in multi-ligament knee injuries despite anatomical reconstruction. The use of a LARS artificial ligament appears to be a valid alternative for PCL reconstruction in the context of multi-ligament injury and in the absence of sufficient autologous transplants.

The Effect of Aging on Outcomes after Posterior Cruciate Ligament Reconstruction: Older (≥ 50 Years) Versus Younger (< 50 Years) Patients.

Background: This study aimed to evaluate the clinical and radiological outcomes after posterior cruciate ligament (PCL) reconstruction in ≥ 50-year-old patients. Methods: This retrospective case-control study reviewed 28 patients (age, ≥ 50 years) who underwent PCL reconstruction from 2004 to 2018. These patients were 1 : 1 matched to < 50-year-old patients by sex. Clinical, radiological, and survivorship outcomes of the patients were assessed at the final follow-up. Failure of PCL reconstruction was defined as the requirement for additional surgery (revision PCL reconstruction, high tibial osteotomy, or arthroplasty) due to unrelieved symptoms or grade III instability on stress radiographs. Results: The mean follow-up periods (± standard deviation) in < 50- and ≥ 50-year-old patients were 3.9 ± 1.0 years and 3.6 ± 1.9 years, respectively (p = 0.583). In < 50- and ≥ 50-year-old patients, the mean International Knee Documentation Committee scores were 64.1 ± 10.3 and 53.5 ± 17.3; mean Lysholm scores were 81.4 ± 13.0 and 66.3 ± 21.5; and mean Tegner activity scores were 6.1 ± 1.4 and 4.8 ± 1.7, respectively (p = 0.032, p = 0.018, and p = 0.016, respectively). Side-to-side differences in posterior translation on Telos stress radiographs at the final follow-up were 4.4 ± 1.4 mm and 6.9 ± 3.0 mm in < 50- and ≥ 50-year-old patients, respectively (p < 0.001). According to Kaplan-Meier analysis, the failure-free survival rates of both groups were significantly different in the follow-up period (p = 0.014). The failure-free survival rates for < 50- and ≥ 50-year-old patients were 100% and 78.6%, respectively. Conclusions: Clinical, radiological, and survivorship outcomes were inferior among ≥ 50-year-old patients after PCL reconstruction. Thus, surgeons should be careful when deciding and performing PCL reconstruction in patients 50 years old or over.

Short-term clinical results of bicruciate-retaining total knee arthroplasty using personalized alignment.

BACKGROUND: Bicruciate-retaining (BCR) prosthesis has been introduced to recreate normal knee movement by preserving both the anterior and posterior cruciate ligaments. However, the use of BCR total knee arthroplasty (TKA) is still debatable because of several disappointing reports. We have been performing BCR TKAs with personalized alignment (PA). This study aimed to reveal the limb alignment and soft tissue balance of FA-BCR TKAs and compare the clinical outcomes of FA-BCR TKAs with those of unicompartmental knee arthroplasty (UKA). METHODS: Fifty BCR TKAs and 58 UKAs were included in this study. The joint component gaps of BCR TKA were evaluated intraoperatively and the postoperative hip-knee-ankle (HKA) angle, medial proximal tibial angle (MPTA), and lateral distal femoral angle (LDFA) were measured using full-length standing radiography. The short-term clinical outcomes of BCR TKAs were compared with those of UKA using the scoring system of 2011 Knee Society Scoring (KSS) and the knee injury and osteoarthritis outcome score (KOOS) at an average of 2 years postoperatively (1-4yeras). RESULTS: The coronal alignment values of PA-BCR TKA were as follows: HKA angle, 177.9° ± 2.3°; MPTA, 85.4° ± 1.9°; and LDFA, 87.5° ± 1.9°. The joint component gaps at flexion angles of 10°, 30°, 60°, and 90° were 11.1 ± 1.2, 10.9 ± 1.4, 10.7 ± 1.3, and 11.2 ± 1.4 mm for the medial compartment and 12.9 ± 1.5, 12.6 ± 1.8, 12.5 ± 1.8 and 12.5 ± 1.7 mm for the lateral compartment, respectively. The patient expectation score and maximum extension angle of PA-BCR TKA were significantly better than those of UKAs. CONCLUSIONS: The short-term clinical outcomes of PA-BCR TKA were comparable or a slightly superior to those of UKAs.

Posterior Cruciate Ligament Agenesis Requiring Surgical Reconstruction.

Agenesis of the posterior cruciate ligament (PCL) is a rare disorder often found in conjunction with various other abnormalities within the knee. A 15-year-old adolescent boy presented with an absent PCL, leading to intermittent symptoms. At the age of 20 years, the patient underwent arthroscopically assisted PCL reconstruction. The patient was permitted to weightbear immediately after the procedure and started physical therapy 4 weeks after the procedure. No complications were encountered at the 2-year follow-up.

The larger patellar tilt angle and lower intercondylar notch angle might increase posterior cruciate ligament injury risk: a retrospective comparative study.

BACKGROUND: Posterior cruciate ligament (PCL) injuries are common ligament injuries of the knee, and previous studies often focused on the associations between the morphology of the knee and PCL injuries. Studies on the correlation between PCL injuries and patellofemoral alignment are limited. METHODS: This retrospective study included 92 patients with PCL injured and 92 patients with PCL intact. Measurement parameters were compared between the two groups, including patellar tilt angle, congruence angle, patellar height, hip-knee-ankle angle, lateral trochlear inclination, femoral condyle ratio, bicondylar width, intercondylar notch width and index, notch angle, trochlear facet asymmetry, and trochlear sulcus depth and angle. Independent risk factors associated with PCL injuries were identified by logistic regression analyses. RESULTS: In the PCL injured group, the patellar tilt angle was significantly larger (13.19 ± 5.90° vs. 10.02 ± 4.95°, P = 0.04); the intercondylar notch angle was significantly lower (60.97 ± 7.83° vs. 67.01 ± 6.00°, P = 0.004); the medial and lateral femoral condyle ratio were significantly larger (0.63 ± 0.64 vs. 0.60 ± 0.56, P = 0.031; 0.65 ± 0.60 vs. 0.58 ± 0.53, P = 0.005) than in the PCL intact group. There were 11 patients with patellar dislocation in the PCL injured group, accounting for 12%. In these patients, the patellar height was higher (1.39 ± 0.17 vs. 1.09 ± 0.25, P = 0.009); the trochlear sulcus angle was larger (157.70 ± 8.7° vs. 141.80 ± 8.78°, P < 0.001); and the trochlear sulcus depth was shallower (3.10 ± 1.20mm vs. 5.11 ± 1.48mm, P = 0.003) than those in the patients without patellar dislocation. Multivariate analyses showed that patellar tilt angle (each increase 1 degree, OR = 1.14) and intercondylar notch angle (each increase 1 degree, OR = 0.90) were independent risk factors for PCL injuries. CONCLUSION: The patients with PCL injuries had larger patellar tilt angles, lower intercondylar notch angles, and longer posterior femoral condyles than patients with PCL intact. The larger patellar tilt angle and lower intercondylar notch angle might be risk factors for PCL injuries.

Arthroscopic Excision of Posterior Cruciate Ligament Cysts Using a Double Posteromedial Approach.

Cruciate ligament cysts of the knee are a rare condition. Posterior cruciate ligament cysts of the knee are less common than anterior cruciate ligament cysts. In patients with asymptomatic isolated cruciate ligament cysts of the knee, conservative treatment is recommended. Symptomatic cruciate ligament cysts of the knee are mostly manifested as knee hyperflexion pain, straightening pain, knee discomfort after standing for a long time or walking for a long time, etc., which seriously affects the quality of life, surgical treatment can be performed. The surgical treatments can be divided into ultrasound-guided cyst puncture and fluid extraction procedure and arthroscopic cystectomy. Cysts are mostly lobulated with a multi-layer cyst wall, cyst fluid extraction does not remove the cyst wall completely but simply extracts cyst fluid, leading to a high recurrence rate. Arthroscopic surgery can completely remove the cyst wall with little trauma, a low recurrence rate, and fast postoperative recovery, so arthroscopic resection is the most common and preferred method of treatment. Since posterior cruciate ligament cysts mostly occur posterior to the ligament, we remove the cyst wall by adding a double posteromedial approach to the knee joint, and the cyst wall is removed under direct vision, which is simple to operate, the cyst wall is completely cleared, the trauma is small, the postoperative recovery is fast, and there is no recurrence. Here, 8 posterior cruciate ligament cysts were removed with complete postoperative symptom relief, no surgical complications, and no recurrence at 1-year follow-up.

12-Year clinical and radiological results of a double-blind randomized controlled trial comparing posterior cruciate-retaining versus posterior-stabilized total knee arthroplasty.

BACKGROUND: A subject of ongoing debate among orthopedic surgeons is the importance of preserving the posterior cruciate ligament in total knee arthroplasty (TKA), but long-term survival studies are scarce. The aim of this study was to compare long-term survival rates, and clinical and radiological follow up of a double-blind randomized controlled trial comparing posterior cruciate-retaining (PCR) versus posterior-stabilizing (PS) implant design of an AGC TKA. METHODS: A total of 114 patients were included in the survival analysis (PCR n = 61; PS n = 53). Forty-five patients (PCR n = 25; PS n = 20) participated in the long-term follow up using patient-reported outcome measures (Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Short-Form Health Survey (SF-36) and Kujala score (measuring anterior knee pain)). Thirty-one patients were assessed with a physical test (Knee Society Score (KSS)) and radiographs. RESULTS: Overall survival rate was 95.6% (PCR 98.4% vs. PS 92.5%), with five patients having a major revision (PCR n = 1 vs. PS n = 4, respectively). Satisfying outcome scores for both groups were described at on average 12-year follow up with no significant differences in KSS knee and function scores, WOMAC, SF-36, or Kujala scores between groups. Radiographically, there were no findings of femoral or tibial loosening or polyethylene wear in either group. CONCLUSIONS: Good long-term survival rates were described for the PCR and the PS design of an AGC TKA. There were no significant differences in clinical and radiological outcomes between a PCR and a PS design 12 years postoperatively.

The posterior cruciate ligament-posterior femoral cortex angle (PCL-PCA) and the lateral collateral ligament (LCL) sign are useful parameters to indicate the progression of knee decompensation over time after an ACL injury.

PURPOSE: The posterior cruciate ligament-posterior cortex angle (angle between the most vertical part of the anterolateral PCL bundle and the posterior diaphyseal cortex of the femur; PCL-PCA) is the most accurate approach to describe the PCL buckling phenomenon observed in anterior cruciate ligament (ACL)-deficient knees. The aim of this study was to determine whether the PCL-PCA is associated with chronicity of the ACL rupture, the meniscal status, preoperative knee laxity or imaging signs such as the lateral collateral ligament (LCL) sign or the posterior tibial slope (PTS) in ACL-injured knees. METHODS: Patients with a primary ACL reconstruction (ACLR) after physeal closure were selected retrospectively from a hospital-based ACL registry from 2015 to 2021. Exclusion criteria were: previous ipsilateral/contralateral knee surgery, previous ipsilateral ACL or meniscal tear, ipsilateral PCL and/or collateral ligament injuries or tibial plateau fracture. The ACL deficiency was defined as chronic if time from injury to MRI was > 6 months. The meniscal status was assessed during ACLR, separately for the medial and lateral meniscus, and classified into no tear, minor or major unstable tear. The MRI analyses included the assessment of the PCL-PCA and the LCL sign. PTS was assessed from the lateral plain radiographs of the injured knee. The side-to-side difference in anterior tibial translation (ATT) at 200N was obtained with the GNRB. RESULTS: Eighty-two patients (forty-eight males/thirty-four females) were included in this study. The median PCL-PCA was 16.2° (Q1-Q3: 10.6-24.7) and differed between acute (18.4°) and chronic (10.7°) injuries (p < 0.01). The median PCL-PCA was significantly lower (- 4.6°) in patients with a positive LCL sign (p = 0.03) No significant association could be found between PCL-PCA and meniscal status, PTS or preoperative anterior knee laxity (Lachman, pivot shift and ATT in millimetres). CONCLUSION: The PCL-PCA was significantly lower in chronic ACL injuries and in patients with a positive LCL sign, indicating a higher buckling phenomenon of the PCL in these patients. These results support the fact that PCL-PCA and the LCL sign may be useful parameters to indicate the progression of knee decompensation over time after an ACL injury, and therefore may constitute a helpful tool to optimise treatment choice and timing of ACL reconstruction if necessary. LEVEL OF EVIDENCE: III.

[Study on the diagnostic value of different posterior cruciate ligament index measurement methods for anterior cruciate ligament injury].

OBJECTIVE: To compare the posterior cruciate ligament(PCL) index with six different measurement methods, and analyze and verify its clinical diagnostic value in anterior cruciate ligament (ACL) injury. METHODS: The Magnetic resonance imaging (MRI) data of 225 knee joints in our hospital from May 2018 to March 2022 were retrospectively analyzed, aged from 18 to 60 years old, with a median of 32 years old. On the sagittal MRI images of 114 patients with ACL injury and 111 patients with intact ACL, Measure the straight-line distance (A) between the femoral attachment point and the tibial attachment point of the PCL on the MRI sagittal image and the maximum vertical distance (B) between the straight line and the arcuate mark point of the PCL on the sagittal image, calculate the PCL index and evaluate the diagnostic value of the PCL index for ACL injury. RESULTS: The PCL index of the ACL normal group and the ACL injury group were statistically described. There was no significant difference in PCL index 1, 2, 3 and 6 between the two groups(P>0.05). The difference of PCL index 4 and 5 between the two groups was statistically significant (P<0.001). This study only found that the PCL index 2, 6 in the ACL normal group had a negative correlation with the patient's age (correlation coefficient=-0.213, -0.819;P<0.05), and the PCL index 5 in the ACL injury group was significantly correlated with the patient's body mass index(BMI)had a negative correlation (correlation coefficient=-0.277, P<0.05). CONCLUSION: The change of PCL index is helpful for the diagnosis of ACL injury, PCL index 4 and 5 can be used as effective reference indexes for diagnosing ACL injury in clinic.

Treatment of a Failed Posterior Cruciate Ligament Avulsion Fracture Fixation in a Skeletally Immature Patient: A Case Report.

CASE: A 12-year-old skeletally immature girl presented with 1 year of persistent instability after an open reduction and internal fixation (ORIF) for a posterior cruciate ligament (PCL) avulsion fracture. With a period of nonoperative management, her PCL stress radiographic measurements significantly decreased and her posterior tibial slope increased because the primary ORIF effectively led to growth arrest with an early fusion of the posterior tibial physis. At age 13 years when she was skeletally mature, revision PCL and fibular collateral ligament (FCL) reconstructions were performed. Promising clinical outcomes were observed at age 17 years. CONCLUSION: Pediatric patients with a failed PCL ORIF can successfully be managed with a period of nonoperative bracing and a revision PCL reconstruction once skeletally mature.

Posterior Cruciate Ligament Femoral Avulsion Fractures in Pediatric Patients: A Report of 2 Interesting Surgical Cases.

CASE: This report describes 2 cases of femoral-sided posterior cruciate ligament (PCL) avulsion injuries. A 10-year-old male patient presented with a chronic nonunion of a bony PCL femoral avulsion. In addition, a 4-year-old boy presented with an acute, displaced PCL femoral avulsion off the medial femoral condyle. Both injuries were repaired using arthroscopic techniques. CONCLUSION: Femoral-sided PCL avulsions are very rare in pediatric patients and have not been reported often. We hope to increase the awareness of PCL femoral avulsion injuries in pediatric patients by describing 2 unique cases.

Posterior cruciate ligament rupture and all-epiphyseal repair with suture tape augmentation in a 5-year-old girl: a case report and review of the literature.

INTRODUCTION: Only a few case reports regarding pediatric posterior cruciate ligament (PCL) ruptures without bone avulsion exist in the literature. The present study aims to share our experience in the diagnosis, treatment, and prognosis of a child with a proximal PCL tear. MATERIALS AND METHODS: This article reports a 5-year-old female diagnosed with a proximal PCL tear. The ruptured PCL was repaired with an all-epiphyseal suture tape augmentation (STA) without evidence of growth plate violation. RESULTS: The suture tape was removed under arthroscopy and revealed the PCL was re-attached at 12 months after the first surgery. And at the time of this report, 36 months after surgery, she was doing well without any problems and with negative posterior drawer test. CONCLUSIONS: Pediatric PCL tear without bone avulsion is rare. However, the torn PCL was noticed healed based on an arthroscopic second-look.

Clinical, patient-reported, radiographic and magnetic resonance imaging findings 11 years after acute posterior cruciate ligament injury treated non-surgically.

BACKGROUND: Long-term consequences of posterior cruciate ligament (PCL) injury such as persistent posterior tibial translation and risk of osteoarthritis development are unclear. Additionally, little data is available describing the natural history of structural morphology of the ruptured PCL. The purpose of the study was to determine the long-term outcome after non-operatively treated PCL injury. METHODS: Over 6-years, all acute knee injuries were documented by subacute MRI (median 8 days [5-15, 25th - 75th percentile] from injury to MRI). Twenty-six patients with acute PCL injury were identified of whom 18 (69%) participated in the long-term follow-up after 11 years. Follow-up included radiographic posterior tibial translation (RPTT) determined using the Puddu axial radiograph. weight-bearing knee radiographs, MRI and KOOS (Knee injury and Osteoarthritis Outcome Score). RESULTS: On subacute MRI, 11 knees displayed total and 7 partial ruptures. At 11 (SD 1.9) years, the median RPTT was 3.7 mm (1.5-6.3, 25th - 75th percentile). Seven knees displayed radiographic osteoarthritis approximating Kellgren-Lawrence grade ≥ 2. All follow-up MRIs displayed continuity of the PCL. Patients with more severe RPTT (> 3.7 mm), had worse scores in the KOOS subscales for symptoms (mean difference 14.5, 95% CI 7-22), sport/recreation (30, 95% CI 0-65) and quality of life (25, 95% CI 13-57) than those with less severe RPTT (≤ 3.7 mm). This was also the case for the KOOS4 (22, 95% CI 9-34). CONCLUSION: Acute PCL injuries treated non-surgically display a high degree of PCL continuity on MR images 11 years after injury. However, there is a large variation of posterior tibial translation with higher values being associated with poorer patient-reported outcomes.

The effect of posterior tibial slope on anteroposterior stability in posterior cruciate retaining total knee arthroplasty.

BACKGROUND: It has been suggested that the posterior tibial slope (PTS) plays an important role in increasing the anteroposterior stability following total knee arthroplasty. Although the relationship between the PTS and the flexion range has been investigated many times, studies on the relationship between PTS and anterior-posterior stability are limited. The primary aim of this study was to investigate the relationship and effects of PTS on anteroposterior stability in posterior cruciate retainer total knee arthroplasty. METHODS: 154 primary TKAs were identified retrospectively to analyze the any association between PTS and anteroposterior laxity following posterior cruciate-retaining total knee arthroplasty in the overall study populations. Anteroposterior displacement was measured at the final follow-up based on the following two procedures: KT-1000 arthrometer and sagittal drawer radiographic images. In addition, the relationship between PTS and functional scores-ROM was examined. RESULTS: There was no correlation between patients' posterior tibial slope and postoperative VAS (r: -0.060, p:0.544), WOMAC (r:0.037, p:0.709), KSS (r: -0.073, p:0.455). In addition, there was no significant correlation between postoperative knee ROM and postoperative PTS (r:0.159, p:0.106). Moreover, no correlation was found between KT-1000 arthrometer and 20 degrees AP translation with PTS. There was a negative correlation between PTS and 70 degrees AP translation (r: -0.281, p:0.008). CONCLUSIONS: This study aimed to clarify the association between instability and AP laxity in flexion of implanted knees, and to determine what degree of AP laxity results of instability. A fundamental finding of this study was that; the optimum TS angle to increase anterior-posterior stability after total knee arthroplasty is between ≥ 4 to < 6 degrees, we also proved that there is no relationship between stability and patient satisfaction.