OBJECTIVE: To summarize the research progress on knee laxity of biomechanics and prevention and treatment after posterior cruciate ligament (PCL) reconstruction. METHODS: The domestic and international literature on the prevention and treatment of knee laxity after PCL reconstruction in recent years was extensively reviewed and analyzed. RESULTS: Different degrees of knee laxity often occur after PCL reconstruction, which can lead to poor prognosis in patients. The causes are associated with a variety of factors, including abnormal graft remodeling (such as differences in healing time and biomechanics among different types of grafts), tunnel position deviation (such as graft wear caused by the "killer turn" effect), and mechanical factors in postoperative rehabilitation (such as improper early weight-bearing and range of motion). These factors may promote graft elongation, increase early posterior tibial translation, and thereby induce knee laxity. CONCLUSION While PCL reconstruction improves knee stability, it is crucial to focus on and prevent postoperative knee laxity. However, current surgical methods are limited by factors such as graft characteristics, surgical technique flaws, and rehabilitation protocols, and thus can not fully correct the issue of abnormal postoperative laxity. Surgical techniques and treatment strategies still need further improvement and optimization to enhance patients' postoperative outcomes and quality of life.
Humans ; Joint Instability/surgery* ; Posterior Cruciate Ligament Reconstruction/adverse effects* ; Posterior Cruciate Ligament/surgery* ; Knee Joint/physiopathology* ; Biomechanical Phenomena ; Range of Motion, Articular ; Postoperative Complications/prevention & control* ; Knee Injuries/surgery*

OBJECTIVE: To summarize research progress on enhanced recovery after posterior cruciate ligament (PCL) reconstruction, clarify the core contradictions, effective intervention methods, and evaluation shortcomings in current clinical practice, and provide theoretical support for optimizing clinical rehabilitation strategies. METHODS: Relevant domestic and international literature in recent years was systematically searched. The key technologies and challenges for enhanced recovery after PCL reconstruction were analyzed from three aspects: the core issues of enhanced recovery after PCL reconstruction, treatment strategies, and the post-reconstruction effectiveness evaluation system. RESULTS: Enhanced recovery after PCL reconstruction mainly faces two core problems. First, there is a balance dilemma between graft tendon protection and knee joint function recovery: the tensile capacity of the graft tendon is weak in the early postoperative period, so excessive weight-bearing easily leads to relaxation, while overly conservative immobilization causes muscle atrophy and joint adhesion. Second, the return-to-sport rate is significantly affected by injury type and treatment method: patients with combined multiple ligament or meniscus injuries have a much lower return-to-sport rate than those with isolated PCL injury, and the risk of return-to-sport failure is higher. Current research mainly promotes rehabilitation from two aspects: physical therapy and surgical technology. Physical therapy runs through the perioperative period: preoperatively, muscle strength training, swelling control, and maintenance of joint range of motion are used to optimize surgical conditions; postoperatively, phased intervention is implemented. Surgical technology focuses on minimally invasive and anatomical approaches: arthroscopic surgery reduces injury, double-bundle reconstruction and internal tension-relief technology improve stability, and modified tunnel positioning and special surgical methods avoid the risk of "Killer Turn". Postoperative functional evaluation adopts multi-dimensional indicators: subjective evaluation relies on scales such as Lysholm and International Knee Documentation Committee (IKDC); objective evaluation assesses stability through Telos stress test and posterior drawer test; imaging evaluation takes MRI as the core; psychological evaluation is assisted by the Tampa scale of kinesiophobia-11 (TSK-11). However, there are obvious shortcomings, such as the lack of PCL-specific evaluation tools. CONCLUSION Enhanced recovery after PCL reconstruction requires the integration of precise surgery, individualized rehabilitation, and comprehensive subjective and objective evaluation. In the future, biomaterials and digital technologies should be integrated to optimize the full-cycle management of PCL reconstruction, thereby improving functional recovery and the effect of return to sports.
Humans ; Posterior Cruciate Ligament Reconstruction/rehabilitation* ; Posterior Cruciate Ligament/injuries* ; Recovery of Function ; Knee Joint/physiopathology* ; Knee Injuries/rehabilitation* ; Return to Sport ; Enhanced Recovery After Surgery ; Tendons/transplantation* ; Arthroscopy

OBJECTIVE: A new three-dimensional(3D) classification of posterior cruciate ligament (PCL) tibial avulsion fracture based on computed tomography(CT) features was established and the significance in clinical treatment was explored in this study. METHODS: From May 2013 to November 2023, 43 cases of PCL tibial avulsion fracture in the Second Hospital of Jilin University were analyzed retrospectively, including 29 males and 14 females, aged (34.3±8.5) years. According to traditional Meyers and McKeever classification, 3 cases were typeⅠ;2 cases of typeⅡ;38 cases were type Ⅲ. Based on the characteristics of CT images, 43 patients were given specific treatment strategies and followed up to evaluate the curative effect. According to the degree of fracture displacement, involved range and the integrity of fracture block demonstrated by CT images, the new three-dimensional classification of PCL avulsion fracture was established. Kappa coefficient was used for consistency test. RESULTS: A new 3D classification of PCL tibial avulsion fracture was established. TypeⅠwas the non-displaced fracture (displacement degree ≤3 mm), in which typeⅠa was the avulsion range limited in the posterior intercondylar fossa, and Ib was the avulsion range beyond the posterior intercondylar fossa. TypeⅡrepresented the displaced fracture in the posterior intercondylar fossa (avulsion limited to the posterior intercondylar fossa and fracture displacement>3 mm), in which typeⅡa represented a slight displacement with a intact broken block and the posterior elevation of the avulsion (hinge mechanism), typeⅡb represented the complete separation of fracture ends with a intact fracture block, and typeⅡc was the comminuted fracture. Type Ⅲ was the displaced fracture beyond the posterior intercondylar fossa (avulsion involving the articular surface of the tibial plateau or the intercondylar ridge and the degree of displacement > 3 mm), among which type Ⅲa was the simple fracture with intact broken block, type Ⅲb represented the comminuted fracture, and type Ⅲc was the complex fracture with tibial plateau fracture. According to this new 3D classification, 43 patients were classified as type Ia in 2 cases and typeⅠb in 1 case;typeⅡa in 2 cases, typeⅡb in 15 cases and typeⅡc in 7 cases;type Ⅲa in 2 cases, type Ⅲb in 5 cases and type Ⅲc in 9 cases. All the 43 cases in this study achieved bone union. At the last follow-up, according to the hospital for special surgery knee score(HSS)evaluation system for the knee joint function, 27 cases were excellent, 11 cases were good, 5 cases were fair. The average Kappa value of inter-observer reliability in the first stage was 0.793, and the second stage was 0.855. The average Kappa value of the whole stage was 0.839, indicating high level of consistency. The average Kappa value of intra-observer reliability was 0.893, indicating high level of consistency. CONCLUSION The 3D classification of PCL tibial avulsion fracture is intuitive, demonstrating a high level of reliability. It has a certain guiding significance for the selection of clinical treatment methods, and it is suggested to be promoted and applied as a new classification system in clinical practice.
Humans ; Male ; Female ; Posterior Cruciate Ligament/surgery* ; Adult ; Tibial Fractures/classification* ; Tomography, X-Ray Computed ; Middle Aged ; Retrospective Studies ; Fractures, Avulsion/classification* ; Imaging, Three-Dimensional ; Young Adult

OBJECTIVE: To evaluate the effects of posterior cruciate ligament(PCL) resection on soft tissue elasticity and knee stability in total knee arthroplasty(TKA). METHODS: Six adult cadaveric knee specimens (involving 10 knees) were included in the study. With the assistance of the robotic system(TiRobot Recon, TINAVI, Beijing), total knee arthroplasty (TKA) was performed sequentially using cruciate retaining (CR) prostheses and posterior stabilizing (PS) prostheses. Between the two surgical procedures, the femoral and tibial osteotomy surfaces were not altered;only the posterior cruciate ligament (PCL) was resected and the intercondylar fossa was treated. After installing the femoral trial component, a soft tissue balance solver was used to apply tension ranging from 30 N to 90 N in 5 N increments at 0°, 10°, and 90° of knee flexion. Meanwhile, the medial and lateral joint gaps were measured synchronously. Based on the tension-gap coupling data, the equivalent elastic coefficients of the medial and lateral soft tissue sleeves at different knee flexion angles, as well as the range of the joint line convergence angle (JLCA) under fixed varus-valgus stress, were calculated. Additionally, the gap balance status under 80 N of tension was analyzed. Self-control comparisons of each indicator were conducted before and after PCL resection to analyze the change patterns. RESULTS: After PCL resection, in the fully extended position (knee flexion 0°). The medial equivalent elastic coefficient was 32.2 (25.7, 63.3) N·mm^-1 for the CR prosthesis and 27.7 (22.0, 51.9) N·mm^-1 for the PS prosthesis, and the statistically significant difference (P=0.013). The range of JLCA was 0.41°(0.26, 0.55)° for the CR prosthesis, which was smaller than 0.75° (0.40, 0.98)° for the PS prosthesis, and the difference was statistically significant(P=0.041). At 90° of knee flexion, the medial joint gap was 10.7(10.1, 11.7) mm for the CR prosthesis, which was smaller than 12.1(10.9, 15.1) mm for the PS prosthesis, with a statistically significant difference(P=0.011). No statistically significant differences were observed in other joint gaps. CONCLUSION PCL resection reduces the rigidity of the medial soft tissues in the fully extended knee and increases the medial joint gap in the flexed position, thereby affecting knee stability and balance. This finding suggests that PS and CR prostheses may require different morphological designs, and there should be differences in indications and osteotomy strategies between CR-TKA and PS-TKA. CR-TKA is more suitable for patients with preoperative medial soft tissue laxity.
Humans ; Posterior Cruciate Ligament/physiopathology* ; Knee Joint/physiopathology* ; Arthroplasty, Replacement, Knee ; Elasticity ; Male ; Female ; Middle Aged ; Aged ; Biomechanical Phenomena ; Adult

OBJECTIVE: To compare the effectiveness between lower tibial tunnel placement combined with internal tension relieving suture and simple lower tibial tunnel placement for posterior cruciate ligament (PCL) reconstruction. METHODS: The clinical data of 83 patients with simple PCL injury who met the selection criteria between January 2014 and February 2022 were retrospectively analyzed. Among them, 44 patients underwent PCL reconstruction through lower tibial tunnel placement combined with internal tension relieving suture (tension relieving suture group), and 39 patients underwent PCL reconstruction through simple lower tibial tunnel placement (control group). Baseline characteristics, including gender, age, body mass index, side of injury, cause of injury, preoperative side-to-side difference (SSD) in posterior tibial translation, visual analogue scale (VAS) score, knee range of motion (ROM), Tegner score, Lysholm score, and International Knee Documentation Committee (IKDC) scores (including symptom, daily activities, and knee function scores) were compared between the two groups, showing no significant difference ( P>0.05). The operation time and intraoperative blood loss were recorded and compared between the two groups. The effectiveness was evaluated by Lysholm score, IKDC scores, Tegner score, VAS score, knee ROM, SSD in posterior tibial translation before operation and at last follow-up, the patient satisfaction at last follow-up, and the postoperative graft recovery was evaluated by MRI. RESULTS: There was no significant difference in operation time and intraoperative blood loss between the two groups ( P>0.05). All patients were followed up 12-60 months, and there was no significant difference between the two groups ( P>0.05). Postoperative MRI showed that the graft was in good condition, and the reconstructed PCL graft had good signal, continuity, and tension. During the follow-up, there was no complication such as re-rupture or donor site discomfort in both groups. At last follow-up, the Lysholm score, IKDC scores, Tegner score, VAS score, knee ROM, and SSD in posterior tibial translation significantly improved in both groups when compared with those before operation ( P<0.05). The changes of Lysholm score, Tegner score, IKDC knee symptom score, and SSD in posterior tibial translation between pre- and post-operation were significantly superior in the tension relieving suture group compared to the control group ( P<0.05). However, no significant difference was found between the two groups in the changes of VAS score, knee ROM, IKDC daily activities score or knee function score between pre- and post-operation, and the satisfaction score ( P>0.05). CONCLUSION Lower tibial tunnel placement combined with internal tension relieving suture PCL reconstruction represents a more effective surgical approach for improving postoperative laxity of PCL and knee function recovery comparing to simple lower tibial tunnel placement PCL reconstruction.
Humans ; Posterior Cruciate Ligament/injuries* ; Tibia/surgery* ; Posterior Cruciate Ligament Reconstruction/methods* ; Range of Motion, Articular ; Treatment Outcome ; Knee Joint/surgery* ; Sutures ; Retrospective Studies ; Suture Techniques ; Female ; Male ; Adult ; Knee Injuries/surgery*

BACKGROUND: Despite the advent of innovative knee prosthesis design, a consistent first-option knee implant design in total knee arthroplasty (TKA) remained unsettled. This study aimed to compare the clinical effects among posterior-stabilized (PS), cruciate-retaining (CR), bi-cruciate substituting (BCS), and bi-cruciate retaining designs for primary TKA. METHODS: Electronic databases were systematically searched to identify eligible randomized controlled trials (RCTs) and cohort studies from inception up to July 30, 2021. The primary outcomes were the range of knee motion (ROM), and the secondary outcomes were the patient-reported outcome measures (PROMs) and complication and revision rates. Confidence in evidence was assessed using Confidence in Network Meta-Analysis. The Bayesian network meta-analysis was performed for synthesis. RESULTS: A total of 15 RCTs and 18 cohort studies involving 3520 knees were included. The heterogeneity and inconsistency were acceptable. There was a significant difference in ROM at the early follow-up when PS was compared with CR (mean difference [MD] = 3.17, 95% confidence interval [CI] 0.07, 7.18) and BCS was compared with CR (MD = 9.69, 95% CI 2.18, 17.51). But at the long-term follow-up, there was no significant difference in ROM in any one knee implant compared with the others. No significant increase was found in the PROMs and complication and revision rates at the final follow-up time. CONCLUSIONS At early follow-up after TKA, PS and BCS knee implants significantly outperform the CR knee implant in ROM. But in the long run, the available evidence suggests different knee prostheses could make no difference in clinical outcomes after TKA with extended follow-up.
Humans ; Arthroplasty, Replacement, Knee ; Posterior Cruciate Ligament/surgery* ; Network Meta-Analysis ; Osteoarthritis, Knee/surgery* ; Knee Joint/surgery* ; Knee Prosthesis ; Range of Motion, Articular

OBJECTIVE: To compare the effectiveness of open reduction of posterior cruciate ligament (PCL) avulsion fracture at tibial insertion of knee joint with absorbable screws fixation and absorbable screw combined with suture anchor fixation. METHODS: The clinical data of 26 patients with PCL avulsion fracture at tibial insertion who met the selection criteria between March 2015 and October 2021 were retrospectively analyzed. Among them, 14 patients were fixed with simple absorbable screw (group A), and 12 patients were fixed with absorbable screw combined with suture anchors (group B). All patients were confirmed by X-ray film, CT, or MRI preoperatively, and got positive results in preoperative posterior drawer tests. There was no significant difference in gender, age, side of affected limb, time from injury to operation, comorbidities, and preoperative Meyers & McKeever classification, Lysholm score, and International Knee Documentation Committee (IKDC) score between the two groups ( P>0.05). The operation time and postoperative complications were recorded and compared between the two groups. At last follow-up, Lysholm score and IKDC score were used to evaluate the improvement of knee function. RESULTS: There was no significant difference in operation time between the two groups ( P>0.05). All incisions healed by first intention, and no complication such as vascular and nerve injury or venous thrombosis occurred. All 26 patients were followed up 9-89 months, with an average of 55.3 months. The follow-up time of group A and group B was (55.7±23.2) and (56.8±29.3) months, respectively, with no significant difference ( t=-0.106, P=0.916). Radiographs showed bone healing in both groups at 3 months after operation, and no complication such as infection and traumatic arthritis occurred. At last follow-up, the posterior drawer test was negative in both groups, and the Lysholm score and IKDC score significantly improved when compared with the pre-operative values ( P<0.05). However, there was no significant difference in the improvement value between the two groups ( P>0.05). CONCLUSION For PCL avulsion fracture at tibial insertion of the knee joint, the open reduction and absorbable screw combined with suture anchor fixation can achieve reliable fracture reduction and fixation, which is conducive to the early rehabilitation and functional exercise, and the postoperative functional recovery of the knee joint is satisfactory.
Humans ; Posterior Cruciate Ligament/injuries* ; Suture Anchors ; Fractures, Avulsion/surgery* ; Retrospective Studies ; Tibial Fractures/surgery* ; Arthroscopy/methods* ; Fracture Fixation, Internal/methods* ; Knee Joint/surgery* ; Bone Screws ; Suture Techniques ; Treatment Outcome

OBJECTIVE: To explore the effectiveness of arthroscopic binding fixation using suture through single bone tunnel for posterior cruciate ligament (PCL) tibial insertion fractures in adults. METHODS: Between October 2019 and October 2021, 16 patients with PCL tibial insertion fractures were treated with arthroscopic binding fixation using suture through single bone tunnel. There were 11 males and 5 females with an average age of 41.1 years (range, 26-58 years). The fractures were caused by traffic accident in 12 cases and sports in 4 cases. The time from injury to operation ranged from 2 to 10 days with an average of 6.0 days. The fractures were classified as Meyers-McKeever type Ⅱ in 4 cases and type Ⅲ in 9 cases, and Zaricznyi type Ⅳ in 3 cases. There were 2 cases of grade Ⅰ, 7 cases of grade Ⅱ, and 7 cases of grade Ⅲ in the posterior drawer test. There were 3 cases combined with lateral collateral ligament injury and 2 cases with meniscus injury. The visual analogue scale (VAS) score, Lysholm score, International Knee Documentation Committee (IKDC) score, and knee range of motion were used to evaluate knee joint function. The posterior drawer test and knee stability tester (Kneelax 3) were used to evaluate knee joint stability. The X-ray films were used to evaluate fracture reduction and healing. RESULTS: All incisions healed by first intention after operation. There was no incision infection, popliteal neurovascular injury, or deep venous thrombosis of lower limbs. All patients were followed up 6-12 months, with an average of 10 months. X-ray films at 6 months after operation showed the fractures obtained bone union. There were 11 cases of grade 0, 4 cases of gradeⅠ, and 1 case of grade Ⅱin posterior drawer test, showing significant difference when compared with preoperative results ( Z=23.167, P<0.001). The VAS score, Lysholm score, IKDC score, knee range of motion, and the results of Kneelax3 examination all significantly improved when compared with preoperative results ( P<0.05). CONCLUSION For adult patients with PCL tibial insertion fractures, the arthroscopic binding fixation using suture through single bone tunnel has the advantages of minimal trauma, good fracture reduction, reliable fixation, and fewer complications. The patient's knee joint function recovers well.
Adult ; Female ; Humans ; Male ; Anterior Cruciate Ligament Injuries/surgery* ; Arthroscopy/methods* ; Knee Joint/surgery* ; Posterior Cruciate Ligament/injuries* ; Suture Techniques ; Sutures ; Tibial Fractures/surgery* ; Treatment Outcome ; Middle Aged

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.
Humans ; Adolescent ; Young Adult ; Adult ; Middle Aged ; Posterior Cruciate Ligament/diagnostic imaging* ; Anterior Cruciate Ligament Injuries/diagnostic imaging* ; Anterior Cruciate Ligament ; Retrospective Studies ; Knee Joint ; Magnetic Resonance Imaging/methods*

The most reliable and convenient measurement method of tibial posterior slope(TPS) and its biomechanical relationship with posterior cruciate ligament (PCL) are still controversial. For X-ray measurement, it is recommended to use full-length lateral X-ray of the lower extremity in quatrous section, which has advantage of highly repeatable and common in the daily diagnosis and treatment process, but it is only applicable to patients with tibial rotation within 15°. When the rotation exceeds 30°, it is difficult to identify the inner contour of platform and is no applicable. If it is only used for daily diagnosis and treatment evaluation, when tibial rotation angle is less than 15°, lateral knee X-ray also has a certain reference significance, but the accuracy could not meet requirements of higher clinical research. For CT measurement method, it could correct tibial rotation, but using the fitting point to measure tibial posterior slope on three-dimensional CT reconstruction is only applicable to knee joint without degeneration, more osteophyte affects the way of using fitting point to determine the plane of tibia with real tibia platform conformity degree, have some limitations. For measurement of MRI, it could not only correct tibial rotation, but also minimize the effect of osteophytes by using tibial anatomical axis as the reference axis, which is a good measurement method. For the biomechanical relationship between tibial posterior slope and tibial posterior slope, increased tibial posterior slope indirectly alleviates tension of PCL through tibial anterior displacement or directly reduces load on posterior cruciate ligament in tibial osteotomies, suggesting a protective mechanism for tibial posterior slope;in total knee arthroplasty with cruciate ligament preserved, the size of tibial posterior slope will affect roll back mechanism of femur. When affected knee with PCL injury, it should be avoid to release then aggravate injury, and the stress could be alleviated by increasing tibial posterior slope appropriately. There has been no unified conclusion on the range of tibial posterior slope that is most beneficial to PCL. The natural tibial posterior slope is between 7 ° and 10°, which is considered to be the most beneficial to protection of PCL, but further studies are needed according to the differences in patients' bone status, surgical methods and so on.
Arthroplasty, Replacement, Knee/methods* ; Femur/surgery* ; Humans ; Knee Joint/surgery* ; Osteophyte/surgery* ; Posterior Cruciate Ligament/surgery* ; Tibia/surgery*