[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.

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.

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.

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.

Posterior Cruciate Ligament Injury After Retrograde Nailing of Periprosthetic Distal Femur Fractures: A Report of 2 Cases.

CASE: A 51-year-old man and 64-year-old woman with bilateral cruciate-retaining total knee arthroplasties (CR-TKAs) who sustained unilateral periprosthetic distal femur fractures above their CR-TKA and experienced knee instability secondary to an iatrogenic posterior-cruciate-ligament (posterior cruciate ligament [PCL]) injury from retrograde intramedullary nailing. Both patients recovered knee stability after undergoing revision surgery. CONCLUSION: Many CR-TKA designs have sufficient medial-lateral intercondylar distance to place a retrograde nail, femoral components with a relatively posterior transition from the trochlear groove to the intercondylar box will necessitate a nail starting point closer to the PCL origin. This may contribute to iatrogenic postoperative knee instability for patients with CR-TKA designs.

Anatomic versus Low Tibial Tunnel in Double-Bundle Posterior Cruciate Ligament Reconstruction: Clinical and Radiologic Outcomes with a Minimum 2-Year Follow-Up.

There is currently no consensus on the optimal placement of the tibial tunnel for double-bundle posterior cruciate ligament (PCL) reconstruction. The purpose of this study was to compare the clinical and radiologic outcomes of double-bundle PCL reconstruction utilizing anatomic versus low tibial tunnels. We conducted a retrospective cohort study involving patients who underwent double-bundle PCL reconstruction between Jan 2019 and Jan 2022, with a minimum follow-up of 2 years (n = 36). Based on the tibial tunnel position on postoperative computed tomography, patients were categorized into two groups: anatomic placement (group A; n = 18) and low tunnel placement (group L; n = 18). We compared the range of motion, stability test, complications, and side-to-side differences in tibial posterior translation using kneeling stress radiography between the two groups. There were no significant differences between the groups regarding clinical outcomes or complication rates. No significant differences in the posterior drawer test and side-to-side difference on kneeling stress radiography (2.5 ± 1.2 mm in group A vs. 3.7 ± 2.0 mm in group L; p = 0.346). In conclusion, the main findings of this study indicate that both anatomic tunnel and low tibial tunnel placements in double-bundle PCL reconstruction demonstrated comparable and satisfactory clinical and radiologic outcomes, with similar overall complication rates at the 2-year follow-up.

Posterior Cruciate Ligament Reconstruction Current Concepts Review.

Posterior cruciate ligament (PCL) injuries are a rare form of knee injury often seen in the setting of high energy polytraumas; however, these injuries can occur in isolation as well. Often, the posterolateral corner (PLC) is involved, which imparts further posterior translational and rotational instability to these injuries. While non-operative management is certainly a reliable option for low grade isolated PCL tears, high grade injuries with concomitant PLC involvement, additional intra-articular pathologies requiring operative management, multiligamentous injuries, or patients who have failed non-operative management require PCL repair or reconstruction. The current review focuses on the many facets of PCL reconstruction, including single versus double bundle reconstruction, tibial slope implications, graft selection, multiligamentous injury considerations, tunnel management, and onlay versus inlay tibial footprint creation. We conclude with a proposed algorithm in the management of this injury.

[Arthroscopic suspension fixation with Endobutton in treatment of tibial insertion avulsion fractures of posterior cruciate ligament].

Objective: To investigate the effectiveness of arthroscopic suspension fixation with Endobutton in the treatment of tibial insertion avulsion fractures of posterior cruciate ligament (PCL). Methods: A retrospective analysis was conducted on the clinical data of 52 patients (52 knees) with tibial insertion avulsion fractures of PCL, who were treated by arthroscopic suspension fixation with Endobutton between June 2017 and October 2022. There were 29 males and 23 females, with an average age of 40.6 years (range, 19-66 years). There were 24 cases of traffic accident injuries, 17 cases of sports injuries, and 11 cases of fall injuries. The time from injury to operation ranged from 6 to 19 days (mean, 13.3 days). According to the Meyers-McKeever classification, there were 30 cases of type Ⅱ and 22 cases of type Ⅲ fractures. All patients exhibited positive posterior drawer test results. Preoperative knee joint function was assessed with Lysholm score (21.3±6.7), International Knee Documentation Committee (IKDC) score (20.7±5.8), and visual analogue scale (VAS) score (5.3±0.7); and knee joint range of motion was (41.73±3.17)°. Based on preoperative CT three-dimensional reconstruction measurements, the longitudinal diameter of the avulsed bone fragment ranged from 13 to 25 mm (mean, 18.1 mm). Operation time and occurrence of complications were recorded, and postoperative imaging was used to assess fracture healing. Knee joint function and pain severity were evaluated using knee joint range of motion, Lysholm score, IKDC score, and VAS score. Results: The operation time ranged from 46 to 81 minutes (mean, 56.2 minutes). All patients were followed up 12-28 months (mean, 20.1 months). The iatrogenic fractures of bone fragments occurred during operation in 4 cases; and knee effusion occurred in 2 cases and anterior knee pain in 1 case after operation. All incisions healed by first intention. Imaging evaluations at 3 months after operation showed the fracture healing and no internal fixation failure. All patients demonstrated good knee function and had returned to normal activities at 12 months after operation. At last follow-up, the knee joint range of motion was (133.44±4.17)°, Lysholm score 93.6±3.1, IKDC score 93.4±2.5, and VAS score 1.0±0.6, with significant differences compared to preoperative scores ( P<0.05). Conclusion: Arthroscopic suspension fixation with Endobutton in the treatment of tibial insertion avulsion fractures of PCL is simple to operate, and the knee joint function recovers well.

Comparison of the Kinematics and Laxity of Total Knee Arthroplasty Bearing Designs Stabilized With Specimen-Specific Virtual Ligaments on a Joint Motion Simulator.

A variety of total knee arthroplasty (TKA) designs offer increased congruency bearing options, primarily to compensate for a loss of posterior cruciate ligament (PCL) function. However, their efficacy in providing sufficient stability under different circumstances requires further investigation. The preclinical testing of prosthesis components on joint motion simulators is useful for quantifying how design changes affect joint stability. However, this type of testing may not be clinically relevant because surrounding ligaments are either ignored or greatly simplified. This study aimed to assess the kinematics and stability of TKA joints during various motions using condylar-stabilized (CS) bearings without a PCL versus cruciate-retaining (CR) bearings with an intact PCL. TKA prosthetic components were tested on a joint motion simulator while being stabilized with five different sets of specimen-specific virtual ligament envelopes. In comparison to CR knees, CS knees without a PCL exhibited a greater amount of posterior tibial displacement laxity, with a mean increase of 2.7±2.1 mm (p = 0.03). Additionally, significant differences were observed in the anterior-posterior kinematics of the knee joint during activities of daily living (ADL) between the two designs. These results were consistent with previous cadaveric investigations, which indicated that CS knees without a PCL are less resistant to posterior tibial displacement than CR knees with one. This study employing virtual ligaments confirms previous findings that the raised anterior lip of some CS bearings may not completely compensate for the absence of the PCL; however, as both studies used reduced joint contact forces, the contributions of this design feature may be attenuated.

Risk factors of failure results after double-bundle reconstruction with autogenous hamstring grafts for isolated posterior cruciate ligament rupture cases.

Posterior tibial translation (PTT) after double-bundle posterior cruciate ligament (PCL) reconstruction has sometimes occurred. Purpose of this study is to identify the risk factors for postoperative PTT after double-bundle PCL reconstruction with a hamstring autograft. Comparing the results of bilateral gravity sag view (GSV) at 12 months after surgery, over 5-mm PTT was defined as 'failure' in this study. Of 26 isolated PCL reconstruction cases, over 5-mm PTT was seen in 7 cases (group F: 9.57 ± 1.28 mm), and 19 cases had less than 5 mm (group G: 2.84 ± 1.29 mm). Age, sex, body mass index (BMI), preoperative GSV, posterior slope angle of the tibia, anterolateral bundle (ALB) and posteromedial bundle (PMB) graft diameters, and tibial tunnel diameter were evaluated. The two groups were compared with the 2 × 2 chi-squared test, the Mann Whitney U-test, and Spearman's rank correlation coefficient. Multivariate logistic regression analysis was also performed to determine the risk factor. Statistical significance was indicated as p < 0.01 for correlation with postoperative PTT, and as p < 0.05 for all other comparisons. Mean age (group G 31.8 ± 12.5 vs group F 34.9 ± 15.9 years), sex (male/female: 15/4 vs 3/4), BMI (25.6 ± 4.6 vs 24.9 ± 3.9 kg/m2), preoperative GSV (11.3 ± 2.2 vs 11.6 ± 2.9 mm), PMB diameter (5.37 ± 0.33 vs 5.36 ± 0.48 mm), and tibial tunnel diameter (9.32 ± 0.58 vs 9.29 ± 0.49 mm) showed no significant differences. ALB diameter was significantly greater in group G (7.0 ± 0.5 mm) than in group F (6.5 ± 0.29 mm; p = 0.022). There was also a significant difference in posterior tibial slope angle (group G 9.19 ± 1.94 vs group F 6.54 ± 1.45, p = 0.004). On Spearman rank correlation coefficient analysis, ALB diameter GSV (correlation coefficient: - 0.561, p = 0.003) and posterior tibial slope angle (correlation coefficient: - 0.533, p = 0.005) showed a significant correlation with postoperative PTT. Multivariate logistic regression analysis showed that ALB diameter (OR 19.028; 95% CI 1.082-334.6; p = 0.044) and posterior slope angle of tibia (OR 3.081; 95% CI 1.109-8.556; p = 0.031) were independently associated with postoperative PTT, respectively. In double-bundle PCL reconstruction with hamstring, smaller ALB graft diameter and lower (flatted) tibial slope angle were considered risk factors for postoperative PTT.

Maximum outcome with minimal resources: report of a multiligamentous knee injury managed with 'modified confluent tunnel technique'.

Multiligamentous knee injuries (MLKIs) are rare and challenging to manage in many aspects. The injury requires prompt diagnosis, reconstruction of multiple ligaments, and management of associated neurovascular injuries. Another important aspect that surgeons should consider is resource availability. Successful management of a case of MLKI using the cost-effective 'modified confluent tunnel technique' is described in this case report. We used confluent tunnels for intra- and extra-articular ligament reconstructions at the femoral side. We incorporated the weave technique for medial collateral ligament (MCL) reconstruction, and Larson's technique for posterolateral corner (PLC) reconstruction in this construct, and augmented the anterior cruciate ligament (ACL) and posterior cruciate ligament reconstruction with the remaining PLC and MCL grafts, respectively. This was cost-effective and resulted in good functional outcomes. The technique also helped us to avoid tunnel convergence which is an expected complication in MLKI surgeries.

Rates of Subjective Failure After Both Isolated and Combined Posterior Cruciate Ligament Reconstruction: A Study From the Norwegian Knee Ligament Registry 2004-2021.

BACKGROUND: Outcomes after posterior cruciate ligament (PCL) reconstruction (PCLR) have been reported to be inferior to those of anterior cruciate ligament reconstruction. Furthermore, combined ligament injuries have been reported to have inferior outcomes compared with isolated PCLR. PURPOSE/HYPOTHESIS: The purpose of this study was to report on PCLR outcomes and failure rates and compare these outcomes between isolated PCLR and multiligament knee surgery involving the PCL. The hypothesis was that combined PCL injury reconstruction would have higher rates of subjective failure and revision relative to isolated PCLR. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Patients with primary PCLR with or without concomitant ligament injuries registered in the Norwegian Knee Ligament Registry between 2004 and 2021 were included. Knee injury and Osteoarthritis Outcome Score (KOOS) totals were collected preoperatively and at 2 years and 5 years postoperatively. The primary outcome measure was failure, defined as either a revision surgery or a KOOS Quality of Life (QoL) subscale score <44. RESULTS: The sample included 631 primary PCLR procedures, with 185 (29%) isolated PCLR procedures and 446 (71%) combined reconstructions, with a median follow-up time of 7.3 and 7.9 years, respectively. The majority of patients had poor preoperative knee function as defined by a KOOS QoL score <44 (90.1% isolated PCLR, 85.7% combined PCL injuries; P = .24). Subjective outcomes improved significantly at 2- and 5-year follow-up compared with preoperative assessments in both groups (P < .001); however, at 2 years, 49.5% and 46.5% had subjective failure (KOOS QoL <44) for isolated PCLR and combined PCLR, respectively (P = .61). At 5 years, the subjective failure rates of isolated and combined PCLR were 46.7% and 34.2%, respectively (P = .04). No significant difference was found in revision rates between the groups at 5 years (1.9% and 4.6%, respectively; P = .07). CONCLUSION: Patients who underwent PCLR had improved KOOS QoL scores relative to their preoperative state. However, the subjective failure rate was high for both isolated and multiligament PCLR. Within the first 2 years after surgery, patients who undergo isolated PCLR can be expected to have similar failure rates to patients who undergo combined ligament reconstructions.

Peracetic acid sterilized tendon and ligament allografts for knee reconstruction : For anterior cruciate ligament (ACL), posterior cruciate ligament (PCL) and complex knee surgery.

BACKGROUND: The use of allografts and autografts has been met with mixed views on whether allografts are a suitable alternative to autografts. QUESTION: We aimed to investigate if chemically sterilized allografts show similar rerupture rates to those reported in the literature for allografts and autografts in anterior (ACL) and posterior cruciate ligaments (PCL) and complex knee surgery. MATERIALS AND METHODS: Retrospective data on knee reconstructions performed between 2011 and 2015 with tendon/ligamnet allografts sterilized with peracetic acid were collected in the form of a questionnaire. The inclusion criteria of 2 years for each patient were met by 38 patients, representing 22 ACL reconstructions, 5 PCL reconstructions, 3 OTHER surgeries, including the Larson technique and medial patellofemoral ligament (MPFL) reconstruction and 8 COMPLEX surgeries. The main endpoints were rerupture and complication rate. Secondary endpoints included stability of the knee (Lachman test, Pivot shift test) and the range of motion. RESULTS: The rerupture rate was 7.9% (3 grafts). Reruptures only occurred in the ACL group. No reruptures were observed in the PCL, OTHER and COMPLEX surgery groups. Stability improved significantly after surgery and the range of motion returned to values similar to that of healthy knees. CONCLUSIONS: Tendon allografts sterilized with peracetic acid show promising low rerupture rates and good clinical scores and the results are comparable to the literature on autografts and other allografts.

[Comparison of intraoperative effects of computer navigation-assisted and simple arthroscopic reconstruction of posterior cruciate ligament tibial tunnel].

Objective: To compare the intraoperative effects of computer navigation-assisted versus simple arthroscopic reconstruction of posterior cruciate ligament (PCL) tibial tunnel. Methods: The clinical data of 73 patients with PCL tears who were admitted between June 2021 and June 2022 and met the selection criteria were retrospectively analysed, of whom 34 cases underwent PCL tibial tunnel reconstruction with navigation-assisted arthroscopy (navigation group) and 39 cases underwent PCL tibial tunnel reconstruction with arthroscopy alone (control group). There was no significant difference in baseline data between the two groups, including gender, age, body mass index, side of injury, time from injury to surgery, preoperative posterior drawer test, knee range of motion (ROM), Tegner score, Lysholm score, and International Knee Documentation Committee (IKDC) score between the two groups ( P>0.05). The perioperative indicators (operation time and number of guide wire drillings) were recorded and compared between the two groups. The angle between the graft and the tibial tunnel and the exit positions of the tibial tunnel in the coronal, sagittal, and transverse planes respectively were measured on MRI at 1 day after operation. The knee ROM, Tegner score, Lysholm score, and IKDC score were evaluated before operation and at last follow-up. Results: The operation time in the navigation group was shorter than that in the control group, and the number of intraoperative guide wire drillings was less than that in the control group, the differences were significant ( P<0.05). Patients in both groups were followed up 12-17 months, with an average of 12.8 months. There was no perioperative complications such as vascular and nerve damage, deep venous thrombosis and infection of lower extremity. During the follow-up, there was no re-injuries in either group and no revision was required. The results showed that there was no significant difference in the exit positions of the tibial tunnel in the coronal, sagittal, and transverse planes between the two groups ( P>0.05), but the angle between the graft and the tibial tunnel was significantly greater in the navigation group than in the control group ( P<0.05). At last follow-up, 30, 3, 1 and 0 cases were rated as negative, 1+, 2+, and 3+ of posterior drawer test in the navigation group and 33, 5, 1, and 0 cases in the control group, respectively, which significantly improved when compared with the preoperative values ( P<0.05), but there was no significant difference between the two groups ( P>0.05). At last follow-up, ROM, Tegner score, Lysholm score, and IKDC score of the knee joint significantly improved in both groups when compared with preoperative values ( P<0.05), but there was no significant difference in the difference in preoperative and postoperative indicators between the two groups ( P>0.05). Conclusion: Computer-navigated arthroscopic PCL tibial tunnel reconstruction can quickly and accurately prepare tunnels with good location and orientation, with postoperative functional scores comparable to arthroscopic PCL tibial tunnel reconstruction alone.

[Posterolateral instability of the knee joint]. / Posterolaterale Instabilität des Kniegelenks.

The posterolateral corner of the knee is composed of a multilayered complex of ligamentous, musculotendinous, and capsular structures, which interact in a synergistic stabilizing manner with the central structures, particularly the posterior cruciate ligament. Injuries of the posterolateral corner are generally accompanied by rupture of the posterior cruciate ligament. Depending on the injured structures, injuries of the posterolateral corner result in posterolateral rotational instability alone (Fanelli A) or with lateral instability (Fanelli B/C). For rotational instability alone, isolated popliteus bypass is an effective procedure; with concomitant lateral instability in flexion, additional stabilization of the lateral collateral ligament is required. Most of the various available techniques are described as open reconstruction procedures. In recent years, arthroscopic techniques for posterolateral reconstruction have also been successfully developed.

[Imaging of posterolateral rotational instability of the knee joint]. / Bildgebung bei posterolateraler Rotationsinstabilität des Kniegelenks.

Posterolateral instability of the knee joint typically occurs with injuries to the posterolateral corner of the joint or with additional combined injuries involving the anterior and posterior cruciate ligaments. In addition to numerous, smaller anatomical structures, the most important are the lateral collateral ligament (LCL), the popliteus muscle with its tendon, and the popliteofibular ligament (PFL), which can usually be assessed using magnetic resonance imaging (MRI). On the contrary, small structures like the arcuate ligament and fabellofibular ligament cannot always be identified. However, they are also of lesser importance in the development of posterolateral rotational instability. Overlooked injuries to the posterolateral joint corner promote instability with the complication of inadequate ligament reconstruction and early onset posttraumatic osteoarthritis. Knowledge of MRI morphology of the anatomical structures involved, taking into account their biomechanical significance, is crucial to recognize and use the corresponding imaging findings.

Decreased posterior tibial slope is a risk factor for primary posterior cruciate ligament rupture and posterior cruciate ligament reconstruction failure: A systematic review.

PURPOSE: To determine bony knee morphological factors associated with primary posterior cruciate ligament (PCL) rupture or PCL graft failure after PCL reconstruction. METHODS: Three databases, namely MEDLINE, PubMed and EMBASE, were searched on 30th May 2023. The authors adhered to the PRISMA and R-AMSTAR guidelines as well as the Cochrane Handbook for Systematic Reviews of Interventions. Data such as receiver operating characteristic curve parameters, as well as p-values for comparisons of values between patients with PCL pathology and control patients, were recorded. RESULTS: Nine studies comprising 1054 patients were included. Four studies reported that patients with PCL injury had flatter medial posterior tibial slopes (MTS) than controls, with mean values of 4.3 (range: 3.0-7.0) and 6.5 (range: 5.0-9.2) degrees, respectively. Two studies reported an MTS cutoff value ranging below 3.90-3.93° being a significant risk factor for primary PCL rupture or PCL graft failure. Two studies reported that shallow medial tibial depths were associated with primary PCL rupture, with mean values of 2.1 (range: 2.0-2.2) and 2.6 (range: 2.4-2.7) mm in PCL injury and control groups, respectively. Stenotic intercondylar notches and femoral condylar width were not consistently associated with PCL injuries. CONCLUSION: Decreased MTS is associated with primary PCL rupture and graft failure after PCL reconstruction with values below 3.93° being considered as a significant risk factor. Less common risk factors include shallow medial tibial depth, while femoral condylar width and parameters with regards to the intercondylar notch, such as notch width, notch width index and intercondylar notch volume, demonstrated conflicting associations with primary or secondary PCL injuries. LEVEL OF EVIDENCE: Level III.