Load-Dependent Characteristics of Cruciate-Retaining and Posterior-Stabilized Total Knee Arthroplasty: A Biomechanical Study.

Background: Increased load bearing across the patellofemoral and tibiofemoral articulations has been associated with total knee arthroplasty (TKA) complications. Therefore, the purpose of this study was to quantify the biomechanical characteristics of the patellofemoral and tibiofemoral joints and simulate varying weight-bearing demands after posterior cruciate ligament-retaining (CR) and posterior-stabilized (PS) TKAs. Methods: Eight fresh-frozen cadaveric knees (average age, 68.4 years; range, 40-86 years) were tested using a custom knee system with muscle-loading capabilities. The TKA knees were tested with a CR and then a PS TKA implant and were loaded at 6 different flexion angles from 15° to 90° with progressively increasing loads. The independent variables were the implant types (CR and PS TKA), progressively increased loading, and knee flexion angle (KFA). The dependent variables were the patellofemoral and tibiofemoral kinematics and contact characteristics. Results: The results showed that at higher KFAs, the position of the femur translated significantly more posterior in CR implants than in PS implants (36.6 ± 5.2 mm and 32.5 ± 5.7 mm, respectively). The patellofemoral contact force and contact area were significantly greater in PS than in CR implants at higher KFAs and loads (102.4 ± 12.5 N and 88.1 ± 10.9 N, respectively). Lastly, the tibiofemoral contact force was significantly greater in the CR than the PS implant at flexion angles of 45°, 60°, 75°, and 90° KFA, the average at these flexion angles for all loads tested being 246.1 ± 42.1 N and 192.8 ± 54.8 N for CR and PS implants, respectively. Conclusions: In this biomechanical study, CR TKAs showed less patellofemoral contact force, but more tibiofemoral contact force than PS TKAs. For higher loads across the joint and at increased flexion angles, there was significantly more posterior femur translation in the CR design with a preserved posterior cruciate ligament and therefore significantly less patellofemoral contact area and force than in the PS design. The different effects of loading on implants are an important consideration for physicians as patients with higher load demands should consider the significantly greater patellofemoral contact force and area of the PS over the CR design.

[Posterior cruciate ligament rupture : state of the art]. / Rupture du ligament croisé postérieur : état de l'art.

Posterior cruciate ligament (PCL) ruptures can cause severe knee instability and disability and thus, appropriate management is crucial for the successful restoration of patients' knee function. Rupture of the PCL can occur during sporting activity but more often, as a part of high-energy trauma. The diagnosis can be made using various clinical tests, such as the posterior drawer test or the quadriceps active test. MRI is the gold standard in imaging. PCL injuries can be classified from grade I to grade III, with increasing severity. Treatment can be conservative or surgical and should be personalized based on patients' demographic characteristics, grade of injury, level of instability, associated injuries and activity levels.

Les ruptures du ligament croisé postérieur (LCP) peuvent causer une instabilité sévère du genou et une incapacité importante, rendant ainsi une prise en charge appropriée cruciale pour le rétablissement d'une bonne fonction du genou. La rupture du LCP peut survenir lors d'une activité sportive, mais plus souvent, dans le cadre d'un traumatisme à haute énergie. Le diagnostic peut être posé à l'aide de différents tests cliniques, tels que le test du tiroir postérieur ou le test actif du quadriceps. L'IRM est l'examen de référence en imagerie. Les lésions du LCP peuvent être classées de grade I à III, avec une gravité croissante. Le traitement peut être conservateur ou chirurgical et doit être personnalisé en fonction des caractéristiques démographiques des patients, du grade de la lésion, du niveau d'instabilité, des lésions associées et des niveaux d'activité.

Total knee arthroplasty using a cemented single-radius, condylar-stabilized design performed without posterior cruciate ligament sacrifice.

Aims: Total knee arthroplasty (TKA) with a highly congruent condylar-stabilized (CS) articulation may be advantageous due to increased stability versus cruciate-retaining (CR) designs, while mitigating the limitations of a posterior-stabilized construct. The aim was to assess ten-year implant survival and functional outcomes of a cemented single-radius TKA with a CS insert, performed without posterior cruciate ligament sacrifice. Methods: This retrospective cohort study included consecutive patients undergoing TKA at a specialist centre in the UK between November 2010 and December 2012. Data were collected using a bespoke electronic database and cross-referenced with national arthroplasty audit data, with variables including: preoperative characteristics, intraoperative factors, complications, and mortality status. Patient-reported outcome measures (PROMs) were collected by a specialist research team at ten years post-surgery. There were 536 TKAs, of which 308/536 (57.5%) were in female patients. The mean age was 69.0 years (95% CI 45.0 to 88.0), the mean BMI was 32.2 kg/m2 (95% CI 18.9 to 50.2), and 387/536 (72.2%) survived to ten years. There were four revisions (0.7%): two deep infections (requiring debridement and implant retention), one aseptic loosening, and one haemosiderosis. Results: Kaplan-Meier analysis demonstrated no difference in implant survival according to sex, age, or obesity status. Ten-year PROMs were available for 196/387 (50.6%) surviving patients and were excellent: mean Oxford Knee Score 34.4 (95% CI 32.7 to 36.1); mean Forgotten Joint Score (FJS) 51.2 (95% CI 16.1 to 86.3); mean EuroQol five-dimension five-level questionnaire score 69.9 (95% CI 46.8 to 93.0); 141/196 (71.9%) achieved the 22-point FJS patient-acceptable symptom state (PASS); and 156/196 (79.6%) were "very satisfied or satisfied". Conclusion: This is the only large study reporting ten-year implant survival and functional outcomes of TKA using a cemented single-radius design and with a CS tibial bearing construct. The findings of excellent implant survival, safety, and functional outcomes indicate that this combination is a safe and effective option in routine TKA. Further investigation of this single-radius design TKA with CS tibial bearings with well-matched patient study groups will allow further insight into the performance of these implants.

Clinical efficacy of arthroscopic high-intensity suture binding combined with button plate suspension fixation in the treatment of posterior cruciate ligament tibial avulsion fractures.

PURPOSE: To assess the clinical efficacy of arthroscopic treatment for posterior cruciate ligament (PCL) tibial avulsion fractures using high-intensity suture binding combined with button plate suspension fixation. METHODS: We retrospectively analyzed clinical data from 32 patients with PCL tibial avulsion fractures treated at our hospital from July 2020 to August 2023. We recorded operation time, intraoperative and postoperative complications, and used imaging to assess fracture reduction and healing. Pain and knee function were evaluated using the Visual Analogue Scale (VAS), range of knee motion, Lysholm score, and International Knee Documentation Committee (IKDC) score. STUDY DESIGN: Case series; Level of evidence, 4. RESULTS: All patients were followed for 6 to 18 months, averaging 13.6 months. All incisions healed successfully without postoperative complications. X-rays taken on the first postoperative day showed satisfactory fracture reduction. Three-month post-surgery imaging confirmed healed fractures and no internal fixation failures. At the final follow-up, knee function was well recovered, with only one patient exhibiting a positive posterior drawer test of degree I. Furthermore, the mean VAS score was 0. 5 (range 0.0 to 1.0), active knee extension was 2. 2° (range 0.0 to 5.0), and active knee flexion was 137.7° (range 130.0 to 145.0). The mean Lysholm score was 91.5(range 89.3 to 94.0), and the IKDC score averaged 83.8 ± 3.7, and these outcomes showed statistically significant improvement from preoperative levels (P < 0.001). CONCLUSIONS: Arthroscopic high-intensity suture binding combined with button plate suspension fixation for PCL tibial avulsion fractures offers several benefits: it is minimally invasive, results in less postoperative pain, enables earlier functional exercise, and provides satisfactory clinical outcomes with fewer complications.

An in-vitro three-dimensional surgical simulation technique to predict tibial tunnel length in transtibial posterior cruciate ligament reconstruction.

BACKGROUND: During the transtibial posterior cruciate ligament (PCL) reconstruction, drilling depth excessively longer than the tibial tunnel length (TTL) is an important reason to cause popliteal neurovascular bundle injury when preparing the tibial tunnel. This study aims to develop an in-vitro three-dimensional surgical simulation technique to determine the TTL in anteromedial (AM) and anterolateral (AL) approaches. METHODS: A total of 63 knees' 3-dimensional (3D) computed tomography models were included in this study. The SuperImage system was used to reconstruct the 3D knee model and locate the tibial PCL site. The established 3D knee model and the coordinates of the tibial PCL site were imported into Rhinoceros 3D modeling software to simulate AM and AL tibial tunnel approaches with different tibial tunnel angles (TTA). The TTL and the tibial tunnel height (TTH) were measured in this study. RESULTS: In AM and AL tibial tunnel approaches, the TTL showed a strong correlation with the TTA (for AM: r = 0.758, p < 0.001; for AL: r = 0.727, p < 0.001). The best fit equation to calculate the TTL based on the TTA was Y = 1.04X + 14.96 for males in AM approach, Y = 0.93X + 17.76 for males in AL approach, Y = 0.92X + 14.4 for females in AM approach, and Y = 0.94X + 10.5 for females in AL approach. CONCLUSION: Marking the TTL on the guide pin or reamer could help to avoid the drill bit over-penetrated into the popliteal space to damage the neurovascular structure.

Modified arthroscopic repair of a posterior cruciate ligament tibial avulsion fracture improves IKDC and Lysholm score compared to open reduction.

PURPOSE: The purpose of this study was to analyse the difference between arthroscopic fixation and open reduction internal fixation (ORIF) of posterior cruciate ligament (PCL) tibial avulsion fractures. METHODS: This retrospective study analysed patients with an acute PCL tibial avulsion fracture who underwent surgical treatment at our hospital and follow-up for at least 24 months. Variables based on sex, age, Meyers-McKeever type, surgical method, meniscus tear, external fixation, labour or sports, Lysholm knee score, IKDC score, and KT-1000 value were also recorded. Multifactor unconditional logistic regression and Student's t test with 1:1 propensity score matching (PSM) to remove confounding factors were used for analysis. RESULTS: Sixty-five cases achieved knee function graded as "good" or better, and 9 cases not. Single-factor analysis indicated that Meyers-McKeever type (χ2 = 4.669, P = 0.031) and surgical approach (χ2 = 9.428, P = 0.002) are related to functional outcomes. Multifactorial logistic regression analysis further confirmed that Meyers-McKeever typing (OR = 10.763, P = 0.036, [95% CI 1.174-98.693]) and surgical approach (OR = 9.274, P = 0.008, [95% CI 1.794-47.934]) are independent risk factors affecting prognosis. In addition, PSM verified significant differences in the Lysholm score (t = 3.195, P = 0.006), IKDC score (t = 4.703, P = 0.000) and A-KT/H-KT (t = 2.859, P = 0.012). However, the affected-side KT-1000 value (A-KT, mm, t = 1.225, P = 0.239) and healthy-side KT-1000 value (H-KT, mm, t = 1.436, P = 0.172) did not significantly differ between the two groups. The proportions of cases in which the Lysholm score, IKDC and A-KT/H-KT exceeded the minimal clinically important difference (MCID) were 62.5% (20/32), 62.5% (20/32) and 93.75% (30/32), respectively. CONCLUSION: Compared with ORIF, an arthroscopic approach for PCL tibial avulsion fractures achieves better results. LEVEL OF EVIDENCE: Retrospective cohort study; Level II.

[Comparison of open reduction hollow nail anchoring system with loop plate fixation under arthroscopy for the treatment of posterior cruciate ligament avulsion fractures].

OBJECTIVE: To compare clinical effect between open reduction and fixation with cannulated screw and threaded rivet via posteromedial approach versus arthroscopic Endobutton plate fixation in treating posterior cruciate ligament avulsion fractures. METHODS: Clinical data of 38 patients with posterior cruciate ligament avulsion fractures from July 2020 to December 2021 were analyzed retrospectively, and divided into open reduction and internal fixation group (posterior medial approach hollow anchor system fixation) and arthroscopic fixation group (Endobutton with loop plate fixation under arthroscopy). There were 20 patients in open reduction and internal fixation group, including 16 males and 4 females, aged from 26 to 74 years old with an average of (42.9±18.8) years old;13 patients on the left side and 7 patients on the right side;12 patients were classified to typeⅡand 8 patiens with type Ⅲ according to Meyers-McKeever fractures classification;14 patients were gradeⅡand 6 patients were grade Ⅲ in back drawer test. There were 18 patients in arthroscopic fixation group, including 11 males and 7 females;aged from 24 to 70 years old with an average of (53.5±13.4) years old;11 patients on the left side and 7 patients on the right side;10 patients were classified to typeⅡand 8 patiens with type Ⅲ according to Meyers-McKeever fractures classification;11 patients were gradeⅡand 7 patients were grade Ⅲ in back drawer test. Operation time, blood loss, and quality of immediate reduction were compared between two groups. Knee range of motion, knee back drawer test, and International Knee Documentation Committee(IKDC) grading, KT2000 stability evaluation and Lysholm function score of knee joint were compared at 6 months after operation. RESULTS: All patients were followed up for 8 to 16 months with an average of (12.3±1.9) months. There were no complications such as incision infection, fracture malunion or non-union, and internal fixation loosening occurred. The avulsion fractures of knee joint were reached to imaging healing standard at 6 months after operation. Operation time and blood loss in open reduction and internal fixation group were (56.4±7.1) min and (63.2±10.2) ml, while (89.9±7.4) min and (27.7±8.7) ml in arthroscopic fixation group, respectively, and had significant difference between two groups (P<0.05). There were no differences in immediate reduction quality (χ2=0.257, P=0.612), knee joint range of motion at 6 months after opertaion (t=0.492, P=0.626), knee joint rear drawer test ( χ2=0.320, P=0.572), IKDC classification of knee joint (χ2=0.127, P=0.938), KT2000 stability evaluation (χ2=0.070, P=0.791), and knee Lysholm function score (t=0.092, P=0.282) between two groups. CONCLUSION: Posterior medial approach with hollow anchoring system fixation and arthroscopic Endobutton with loop plate fixation for the treatment of posterior cruciate ligament tibial occlusion avulsion fracture could achieve satisfactory clinical results, and arthroscopic surgery has less bleeding, but also has a longer learning curve and longer operation time than traditional incision surgery. The surgeon needs to make a choice according to clinical situation of patient and their own surgical inclination.

[Treatment of Injuries to the Posterior Cruciate Ligament]. / Therapie von Verletzungen des hinteren Kreuzbandes.

Compared to the anterior cruciate ligament injury, the rupture of the posterior cruciate Ligament (PCL) is the rarer condition. A high healing potential is attributed to the PCL in the literature, which is why conservative therapy is also considered important in addition to surgical treatment 1. Posterior cruciate ligament rupture is often associated with concomitant injuries. Among other things, up to 70% of cases are associated with accompanying injuries to the posterolateral corner 2. The detection of concomitant injuries has a significant influence on the outcome, as isolated surgical PCL stabilization does not lead to satisfactory results in these cases.

Posterior Cruciate Ligament Injuries in Very Young Children - A Case Report and Modern Review.

Background: Posterior cruciate ligament (PCL) tears in young children are rare and optimal treatment is poorly described. Diagnosis may prove challenging as young children may not be able to verbalize a complete history of injury, may be difficult to examine, and plane film radiographs often appear within normal limits. Surgical treatment carries a risk of physeal arrest, but non-operative treatment may lead to recurrent instability and pain. Methods: We present a case report of a fouryear- old child with a PCL avulsion off the femoral insertion who received an open reduction and internal fixation (ORIF) with combined arthroscopic synovial debridement. We performed a literature review which compared the mechanism, location, concomitant injuries, work up and management of PCL injuries in children under the age of ten compared to adolescents and adults. Results: Nineteen months following surgery, physical examination revealed full knee range of motion and return to baseline function. Imaging studies confirmed there was no evidence of physeal arrest. Conclusion: ORIF with arthroscopy can be an effective method to treat PCL avulsions in children under the age of 10 years. This is similar to other case reports which reported positive outcomes with ORIF in this population. Large studies are needed to best understand optimal treatment modalities for PCL injuries in very young children. Level of Evidence: IV.

Comparison of the in vivo kinematics between robotic-assisted Bi-cruciate retaining and Bi-cruciate stabilised total knee arthroplasty.

BACKGROUND: Up to 20% of patients remain unsatisfied after total knee arthroplasty (TKA), prompting the development of new implants. Bi-Cruciate Retaining (BCR) TKA preserves both the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL), with the ACL beneficial for its proprioceptive qualities. The Bi-Cruciate Stabilised (BCS) TKA substitutes the ACL and PCL with a unique dual cam-post mechanism. Robotics improve accuracy and facilitate technically demanding TKA. METHODS: This was a retrospective case-control study recruited from two centres. Measured outcomes included kinematic analysis, proprioception, and functional outcomes. RESULTS: There was a significantly larger maximum flexion angle and range of flexion to extension in sit-to-stand and stairs in BCR when compared to BCS. Further analysis revealed more similarities between BCR and normal native knees. Proprioception and functional scores did not have any statistical difference. CONCLUSION: BCR TKA demonstrated better knee flexion in weight-bearing active range of motion and showed similarities with normal knee kinematics.

Effect of Posterior Cruciate Ligament Resection on Gap Balancing in Robot-assisted Total Knee Arthroplasty.

OBJECTIVE: Retention or sacrifice of the posterior cruciate ligament (PCL) is one of the most controversial issues while performing total knee arthroplasty (TKA). This study aimed to evaluate the impact of PCL resection on flexion-extension gaps, femoral component rotation, and bone resection amounts during robot-assisted TKA. METHODS: This prospective study included 40 patients with knee osteoarthritis who underwent robot-assisted posterior-stabilized (PS) TKA between September 2021 and February 2022. Of the patients, 75% were women (30/40) with a mean age and BMI of 72.6 years and 27.4 kg/m2, respectively. The guidance module and camera stand assembly were used to capture gaps before and after PCL resection. Measurements of femoral component rotation and bone resection amounts were made in cruciate-retaining (CR) TKA mode and PS-TKA mode. RESULTS: After PCL resection, the mean change in the medial and lateral compartments of flexion gaps increased by 2.0 and 0.6 mm, respectively (p < 0.001). Compared with the CR-TKA mode group, the bone resection amounts of the medial posterior condyle and the lateral posterior condyle in the PS-TKA mode group decreased by 2.0 ± 1.1 and 1.1 ± 1.1 mm, respectively, and the external rotation of the femoral prosthesis relative to the posterior condylar axis and trans-epicondylar line was reduced by 1.0° ± 1.3° and 1.2° ± 1.6°, respectively (p < 0.001). CONCLUSION: The release of the PCL did not affect the extension gap, but significantly increased the flexion gap. Moreover, the increases in the medial flexion gap were greater than those of the lateral flexion gap. After PCL resection, less external rotation of the femoral prosthesis and fewer bone cuts of the posterior femur were needed in PS-TKA.

Surgical approach on combined chronic patellar tendon and bicruciate knee ligament injury.

A combined injury of the patellar tendon and both the anterior and posterior cruciate ligaments is disabling. It directly affects knee kinematics and biomechanics, presenting a considerable surgical challenge. In this complex and uncommon injury, decision-making should take into account the surgeon's experience and consider one- or two-stage surgery, tendon graft, graft fixation, and rehabilitation protocol. This manuscript discusses the surgical approach based on a comprehensive understanding of the patellar tendon and bicruciate biomechanics to guide which structures should be reconstructed first, especially when a two-stage procedure is chosen.

Activity-Dependent Compensation at the Hip and Ankle at 8 Years After the Reconstruction of Isolated and Combined Posterior Cruciate Ligament Injuries.

BACKGROUND: After posterior cruciate ligament reconstruction (PCLR), functional deficits at the knee can persist. It remains unclear if neighboring joints compensate for the knee during demanding activities of daily living. PURPOSE: To assess long-term alterations in lower limb mechanics in patients after PCLR. STUDY DESIGN: Descriptive laboratory study. METHODS: A total of 28 patients who had undergone single-bundle unilateral isolated or combined PCLR performed stair navigation, squat, sit-to-stand, and stand-to-sit tasks at 8.2 ± 2.2 years after surgery. Motion capture and force plates were used to collect kinematic and kinetic data. Then, 3-dimensional hip, knee, and ankle kinematic data of the reconstructed limb were compared with those of the contralateral limb using statistical parametric mapping. RESULTS: Side-to-side differences at the knee were primarily found during upward-driven movements at 8 years after surgery. The reconstructed knee exhibited lower internal rotation during the initial loading phase of stair ascent versus the contralateral knee (P = .005). During the sit-to-stand task, higher flexion angles during the midcycle (P = .017) and lower external rotation angles (P = .049) were found in the reconstructed knee; sagittal knee (P = .001) and hip (P = .016) moments were lower in the reconstructed limb than the contralateral limb. In downward-driven movements, side-to-side differences were minimal at the knee but prominent at the ankle and hip: during stair descent, the reconstructed ankle exhibited lower dorsiflexion and lower external rotation during the midcycle versus the contralateral ankle (P = .006 and P = .040, respectively). Frontal hip moments in the reconstructed limb were higher than those in the contralateral limb during the stand-to-sit task (P = .010); during squats, sagittal hip angles in the reconstructed limb were higher than those in the contralateral limb (P < .001). CONCLUSION: Patients after PCLR exhibited compensations at the hip and ankle during downward-driven movements, such as stair descent, squats, and stand-to-sit. Conversely, residual long-term side-to-side differences at the knee were detected during upward-driven movements such as stair ascent and sit-to-stand. CLINICAL RELEVANCE: After PCLR, side-to-side differences in biomechanical function were activity-dependent and occurred either at the knee or neighboring joints. When referring to the contralateral limb to assess knee function in the reconstructed limb, concentric, upward-driven movements should be prioritized. Compensations at the hip and ankle during downward-driven movements lead to biases in long-term functional assessments.

Developing a Machine-Learning Predictive Model for Retention of Posterior Cruciate Ligament in Patients Undergoing Total Knee Arthroplasty.

OBJECTIVE: Predicting whether the posterior cruciate ligament (PCL) should be preserved during total knee arthroplasty (TKA) procedures is a complex task in the preoperative phase. The choice to either retain or excise the PCL has a substantial effect on the surgical outcomes and biomechanical integrity of the knee joint after the operation. To enhance surgeons' ability to predict the removal and retention of the PCL in patients before TKA, we developed machine learning models. We also identified significant feature factors that contribute to accurate predictions during this process. METHODS: Patients' data on TKA continuously performed by a single surgeon who had intended initially to undergo implantation of cruciate-retaining (CR) prostheses was collected. During the sacrifice of PCL, we utilized anterior-stabilized (AS) tibial bearings. The dataset was split into CR and AS categories to form distinct groups. Relevant information regarding age, gender, body mass index (BMI), the affected side, and preoperative diagnosis was extracted by reviewing the medical records of the patients. To ensure the authenticity of the research, an initial step involved capturing X-ray images before the surgery. These images were then analyzed to determine the height of the medial condyle (MMH) and lateral condyle (LMH), as well as the ratios between MLW and MMH and MLW and LMH. Additionally, the insall-salvati index (ISI) was calculated, and the severity of any varus or valgus deformities was assessed. Eight machine-learning methods were developed to predict the retention of PCL in TKA. Risk factor analysis was performed using the SHApley Additive exPlanations method. RESULTS: A total of 307 knee joints from 266 patients were included, among which there were 254 females and 53 males. A stratified random sampling technique was used to split patients in a 70:30 ratio into a training dataset and a testing dataset. Eight machine-learning models were trained using data feeding. Except for the AUC of the LGBM Classifier, which is 0.70, the AUCs of other machine learning models are all lower than 0.70. In importance-based analysis, ISI, MMH, LMH, deformity, and age were confirmed as important predictive factors for PCL retention in operations. CONCLUSION: The LGBM Classifier model achieved the best performance in predicting PCL retention in TKA. Among the potential risk factors, ISI, MMH, LMH, and deformity played essential roles in the prediction of PCL retention.

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.

Unicompartmental knee arthroplasty combined with posterior cruciate ligament reconstruction: a case report.

BACKGROUND: In this study, we present the unique case of a patient with knee osteoarthritis (OA) of the medial compartment and posterior cruciate ligament (PCL) deficiency who underwent simultaneous medial unicompartmental knee arthroplasty (UKA) and PCL reconstruction. CASE PRESENTATION: A 49-year-old male patient presented with a 1-year history of pain and instability in the left knee. The patient had previously experienced a trauma-related injury to the PCL of the left knee that was left untreated. Imaging and physical examination confirmed the presence of left medial knee OA along with PCL rupture. To address these issues, the patient underwent UKA combined with PCL reconstruction. The patient's Lysholm score was 47 before surgery and 81 three months after surgery, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score was 29 before surgery and 18 three months after surgery, and the International Knee Documentation Committee (IKDC) subjective score was 56.3 before surgery and 74.7 three months after surgery. Six months after surgery, the patient's gait returned to normal, and he was able to jog. CONCLUSION: This case report presents the first instance of UKA combined with PCL reconstruction and introduces a novel treatment approach for patients suffering from medial knee OA and ligament injury.

Clinical efficacy and kinematic analysis of Chinese knotting technique-assisted posterior cruciate ligament reconstruction: A retrospective analysis.

To investigate the clinical efficacy and knee joint kinematic changes of posterior cruciate ligament (PCL) reconstruction assisted by Chinese knotting technique (CKT). A retrospective analysis was conducted on 88 cases of PCL reconstructive surgery admitted between September 2016 and September 2020. All patients were operated on by the same senior doctor and his team. The patients were divided into 2 groups according to whether the CKT was applied, with 44 cases in each group. Both groups received active rehabilitation treatment after surgery. All patients were followed up for more than 2 years. International knee documentation committee, hospital for special surgery (HSS), and Lysholm scores were used to evaluate the clinical efficacy of the 2 methods at 3, 12, and 24 months after surgery. The motion cycle and kinematic indices of the knee joint were measured by the Opti_Knee three-dimensional motion measurement system before surgery and at 3, 12, and 24 months after surgery. A secondary arthroscopic examination was performed at 12 months after surgery, MAS score was used to evaluate the secondary endoscopic examination of PCL. All the patients had wound healing in stage I without infection. International Knee in both sets Documentation Committee scores, HSS scores and Lysholm scores were gradually improved at all time points (P < .05); compared with the traditional group, the HSS score was higher in the reduction group 12 months after surgery (P < .05), but there was no significant difference at 24 months after surgery. 12 months and 24 months after 3 dimensional motion measurement system using Opti_Knee showed a reduction group before and after displacement and displacement of upper and lower range than the traditional group (P < 0. 05). One year after surgery, the good and good rate of MAS score reduction group was higher than traditional group. CKT assisted PCL reconstruction can improve the subjective function score of the affected knee joint and the results of secondary microscopy. Satisfactory knee kinematic function can be obtained in the early stage, and the anteroposteric relaxation of the knee joint can be reduced.

The tibial capsular reflection and septum in posterior compartment are safe and reliable soft-tissue landmark for tibial tunnel drilling in posterior cruciate ligament reconstruction.

PURPOSE: To investigate the validity of using tibial capsular reflection and septum in the posterior compartment as landmark during posterior cruciate ligament (PCL) reconstruction (PCLR). METHODS: Anatomic measurements were obtained for 12 fresh human cadaveric knee specimens to observe the spatial position of the tibial insertion of the PCL in relation to the posterior septum and the capsular reflection in the posterior compartment. Sixty patients who underwent reconstruction of the PCL between 2020 and 2023 were also retrospectively investigated. The tibial tunnel was replaced in all patients using the same method (with reference to the tibial capsular reflection and the posterior septum). The placement of the tibial tunnel was assessed using X-ray fluoroscopy intraoperatively and computed tomography and three-dimensional reconstruction postoperatively. RESULTS: All fibres in the tibial insertion of the PCL in the 12 cadaveric specimens were located in the posteromedial compartment, adjacent to the posterior septum. The inferior border of the PCL insertion is adjacent to the tibial capsular reflection, which is attached at the champagne glass drop-off of the posterior tibia. In our previous cases, none of the patients experienced postoperative or intraoperative complications such as neurovascular injury, and the angle between the pin and the PCL facet was 93.1 ± 3.9° as measured on intraoperative radiographs. The mean distance from the centre of the tibial tunnel outlet to the inferior border of the PCL insertion was 5.6 ± 1.1 mm, and the distance from the centre of the tibial tunnel outlet to the outer border of the PCL insertion as a percentage of the length of the inferior border of PCL insertion was 42.2 ± 6.3%. CONCLUSION: The tibial capsular reflection and septum in the posterior compartment are safe and reliable soft-tissue landmark for tibial tunnel drilling in PCLR. LEVEL OF EVIDENCE: Level Ⅳ.

Impact of Selective Posterior Cruciate Ligament Fiber Release on Femoral Rollback in Cruciate-Retaining Total Knee Arthroplasty: A Computational Study.

BACKGROUND: Partial or total release of the posterior cruciate ligament (PCL) is often performed intraoperatively in cruciate-retaining total knee arthroplasty (CR-TKA) to alleviate excessive femoral rollback. However, the effect of the release of selected fibers of the PCL on femoral rollback in CR-TKA is not well understood. Therefore, we used a computational model to quantify the effect of selective PCL fiber releases on femoral rollback in CR-TKA. METHODS: Computational models of 9 cadaveric knees (age: 63 years, range 47 to 79) were virtually implanted with a CR-TKA. Passive flexion was simulated with the PCL retained and after serially releasing each individual fiber of the PCL, starting with the one located most anteriorly and laterally on the femoral notch and finishing with the one located most posteriorly on the medial femoral condyle. The experiment was repeated after releasing only the central PCL fiber. The femoral rollback of each condyle was defined as the anterior-posterior distance between tibiofemoral contact points at 0° and 90° of flexion. RESULTS: Release of the central PCL fiber in combination with the anterolateral (AL) fibers, reduced femoral rollback a median of 1.5 [0.8, 2.1] mm (P = .01) medially and by 2.0 [1.2, 2.5] mm (P = .04) laterally. Releasing the central fiber alone reduced the rollback by 0.7 [0.4, 1.1] mm (P < .01) medially and by 1.0 [0.5, 1.1] mm (P < .01) laterally, accounting for 47 and 50% of the reduction when released in combination with the AL fibers. CONCLUSIONS: Releasing the central fibers of the PCL had the largest impact on reducing femoral rollback, either alone or in combination with the release of the entire AL bundle. Thus, our findings provide clinical guidance regarding the regions of the PCL that surgeons should target to reduce femoral rollback in CR-TKA.

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.