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: 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

OBJECTIVETo evaluate clinical outcomes of anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstruction under arthroscopy combined with limited open repair of medial collateral ligament (MCL) for the treatment of multiple ligament injuries of knee joints.

METHODSFrom March 2006 and June 2012,the data of 14 patients (14 knees) with multiple injuries of ACL, PCL, and MCL were collected. There were 8 males and 6 females with an average age of (31.8 +/- 8.1) years old (ranged, 20 to 49 years old). All the patients were performed with X-ray and MRI examination, and the results showed that 10 patients had combined with injuries of anterior cruciate ligament (ACL), posterior cruciate ligament (PCL) and medial collateral ligament (MCL); 4 patients had ALC,PCL and posterolateral corner (PLC) injuries. Four patients had medial meniscus injuries and 2 patients had lateral meniscus injuries. The MCL,PLC and meniscus injuries were treated with operation on the first stage, and functional exercises were performed 3 weeks after fixation. The reconstruction operation of ACL and (or) PCL was performed at the second stage under arthroscopy 3 to 6 months later when the movement range of knee joint recovered to the normal level with obvious relaxation.

RESULTSAll incisions healed by primary intention. All the patients were followed up with a mean duration of 48.9 months (ranged, 24 to 80 months). The Lysholm score was improved from preoperative 19.6 +/- 0.9 to the latest follow-up 87.1 +/- 2.8 (t=12.3, P<0.01). The International Knee Documentation Committee (IKDC) rating: 9 cases nearly recovered to normal, 5 cases were abnormal.

CONCLUSIONFor multiple ligament injuries in the knee, staged repair and reconstruction can effectively restore knee joint stability and function.

Adult ; Anterior Cruciate Ligament ; surgery ; Anterior Cruciate Ligament Injuries ; Female ; Follow-Up Studies ; Humans ; Knee Injuries ; physiopathology ; surgery ; Knee Joint ; physiopathology ; surgery ; Male ; Middle Aged ; Posterior Cruciate Ligament ; injuries ; surgery ; Reconstructive Surgical Procedures ; Treatment Outcome ; Young Adult

OBJECTIVETo study the curative effects of the treatment of tibial avulsion fracture of the posterior cruciate ligament with open reduction and steel-wire internal fixation.

METHODSFrom January 2003 to June 2009, 28 patients of tibial avulsion fracture of the posterior cruciate ligament were treated with open reduction and steel-wire internal fixation through posteromedial inverted "L" approach. There were 19 males and 9 females with an average age of 35.3 years old ranging from 16 to 55 years. The X-ray examination showed that there were II degree displaced in 10 cases and III degree in 18 patients. The affected lower extremity was put in a controlled hinge knee brace after operation. The patients were asked to do passive extension and flexion of the knee joint with the assistance of a CPM 2 weeks after operation,and allowed to be partial weight-bearing as tolerated with the hinged brace locked in extension if concomitant injuries allowed 4 weeks postoperatively. The brace were removed 6 weeks later.

RESULTSAmong them, 25 patients were followed up for 6 to 24 months with an average of 15 months. The X-ray examination showed satisfactory reduction, and bony union was obtained in all the patients. The Lachman test was negative in all patients. No complications such as malunion or joint stiffness were found. The extension of affected knee was normal and its flexion were (136 +/- 12) degrees. According to Lysholm knee score system,it was preoperatively (41.80 +/- 6.16) and (94.10 +/- 8.26) six months after surgery respectively. Twenty-two cases were excellent, 2 cases good and 1 fair.

CONCLUSIONTreatment of tibial avulsion fracture of the posterior cruciate ligament with open reduction and internal fixation with wires through posteromedial inverted "L" approach is a safe, effective method, due to its stable fixation and relatively low expense. It is believed as an ideal choice for tibial avulsion fracture of the posterior cruciate ligament.

Adolescent ; Adult ; Female ; Fracture Fixation, Internal ; methods ; Humans ; Male ; Middle Aged ; Posterior Cruciate Ligament ; diagnostic imaging ; injuries ; physiopathology ; surgery ; Tibial Fractures ; diagnostic imaging ; physiopathology ; surgery ; Tomography, X-Ray Computed ; Treatment Outcome ; Young Adult

OBJECTIVETo study the performance of MRI and its diagnostic value for ligament injuries of knee joint.

METHODSForm June 2008 to February 2010, the MRI of 74 patients with ligament injuries of knee joint were retrospectively analyzed. There were 47 males and 27 females in the group, which course was from 2 h to 10 d, with an average age of 37.3 years (ranged from 12 to 76). The clinical symptom included knee swelling, pain, joint instability, extension-flexion movement disorder. The physical examination showed valgus test or drawer test positive, and tenderness of medial knee positive.

RESULTSThere were ligament injuies in 74 cases, among them, 19 cases were anterior cruciate ligament (25.7%),18 were posterior cruciate ligament (24.3%), 13 were lateral collateral ligament (17.6%), 24 were medial collateral (32.4%), the ligament of 12 cases were completely broken (included 8 cases cruciate ligament and 4 cases collateral ligament presented as discontinued signals of the ligament, and swelling and thickening of the ligament with medium signal in PDWI and high signal intensity in T2WI and in SPIR). The MRI of 62 patients with partial longitudinal tearing ligaments showed continuity, swelling and thickening of the ligaments with medium signal in PDWI and high signal intensity in T2WI and in SPIR. Forty-four cases were examined with surgery and arthroscopy, 41 ligaments were accorded with MRI, diagnosis rate of MRI was 95%.

CONCLUSIONMRI can accurately diagnose the ligament injuries of knee joint,which is an ideal technique in the diagnosis of ligament injuries of knee joint, and should be used as a routine examining method.

Adolescent ; Adult ; Aged ; Anterior Cruciate Ligament Injuries ; Arthroscopy ; methods ; Child ; Female ; Humans ; Joint Instability ; diagnosis ; Knee Injuries ; diagnosis ; physiopathology ; Knee Joint ; physiopathology ; Ligaments ; physiopathology ; Magnetic Resonance Angiography ; methods ; Magnetic Resonance Imaging ; methods ; Male ; Middle Aged ; Posterior Cruciate Ligament ; injuries ; Young Adult

Adolescent ; Adult ; Female ; Follow-Up Studies ; Humans ; Knee ; physiopathology ; surgery ; Male ; Middle Aged ; Posterior Cruciate Ligament ; physiopathology ; surgery ; Tibial Fractures ; physiopathology ; surgery ; Young Adult

BACKGROUND: To determine if tibial positioning affects the external rotation of the tibia in a dial test for posterolateral rotatory instability combined with posterior cruciate ligament (PCL) injuries. METHODS: Between April 2007 and October 2007, 16 patients with a PCL tear and posterolateral rotatory instability were diagnosed using a dial test. The thigh-foot angle was measured at both 30degrees and 90degrees of knee flexion with an external rotation stress applied to the tibia in 2 different positions (reduction and posterior subluxation). The measurements were performed twice by 2 orthopedic surgeons. RESULTS: In posterior subluxation, the mean side-to-side difference in the thigh-foot angle was 11.56 +/- 3.01degrees at 30degrees of knee flexion and 11.88 +/- 4.03degrees at 90degrees of knee flexion. In the sequential dial test performed with the tibia reduced, the mean side-to-side difference was 15.94 +/- 4.17degrees (p < 0.05) at 30degrees of knee flexion and 16.88 +/- 4.42degrees (p = 0.001) at 90degrees of knee flexion. The mean tibial external rotation was 5.31 +/- 2.86degrees and 6.87 +/- 3.59degrees higher in the reduced position than in the posterior subluxation at both 30degrees and 90degrees of knee flexion. CONCLUSIONS: In the dial test, reducing the tibia with an anterior force increases the ability of an examiner to detect posterolateral rotary instability of the knee combined with PCL injuries.
Adolescent ; Adult ; Biomechanics ; Female ; Humans ; Joint Instability/*diagnosis/physiopathology ; Knee Joint/*physiopathology ; Male ; Middle Aged ; *Physical Examination ; Posterior Cruciate Ligament/*injuries/physiopathology ; Range of Motion, Articular ; Tibia/*physiopathology ; Young Adult

OBJECTIVETo compare the effects of increased posterior tibial slope or partial posterior cruciate ligament (PCL) release on knee kinematics of total knee arthroplasty (TKA).

METHODSAnteroposterior laxity, rotational laxity, varus and valgus laxity and maximum flexion angle were evaluated in 6 normal cadaver knees and the knees after TKA at flexion 0 degrees , 30 degrees , 60 degrees , 90 degrees and 120 degrees . Then the femoral prosthesis was shifted 5 mm posteriorly to simulate the tightly implanted knee. The same tests were performed on the tightly implanted knees. After that, the posterior tibial slope was increased 4 degrees or the PCL was partially released, and the same tests were made as in the normal knees respectively. Statistical analysis of the results was made using student's t test.

RESULTSAnteroposterior laxity, rotational laxity and varus and valgus laxity of the tightly implanted knees at flexion 30 degrees , 60 degrees , 90 degrees and 120 degrees were significantly less than those of the normal TKA knees (P < 0.05). Compared with the tightly implanted knees, anteroposterior laxity, rotational laxity and varus and valgus laxity at flexion 30 degrees , 60 degrees , 90 degrees and 120 degrees significantly improved after increased 4 degrees posterior tibial slope (P < 0.05); in the partial PCL released group, anteroposterior laxity at flexion 30 degrees , 60 degrees , 90 degrees and 120 degrees was significantly improved (P < 0.05), varus and valgus laxity was significantly improved only at flexion 90 degrees (P < 0.05), and rotational laxity was significantly improved at flexion 30 degrees , 60 degrees and 90 degrees (P < 0.05). Compared with PCL released group, varus and valgus laxity at flexion 30 degrees , 60 degrees and 90 degrees and rotational laxity at flexion 0 degrees , 30 degrees , 60 degrees and 90 degrees were significantly improved in the group of increased 4 degrees posterior tibial slope (P < 0.05). Maximum flexion angle of the tightly implanted knee (120.4 degrees ) was less than that of the normal TKA knees (130.3 degrees , P < 0.05) and that of increased 4 degrees posterior tibial slope group (131.1 degrees , P < 0.05). There was no significant difference at the maximum flexion angle between the increased 4 degrees posterior tibial slope group and the PCL released group (131.1 degrees vs 124.0 degrees , P = 0.0816).

CONCLUSIONSAnteroposterior laxity, varus and valgus laxity, rotational laxity and maximum flexion angle of the tightly implanted knees are less than those of the normal TKA knees. After increased 4 degrees posterior tibial slope, these indexes are improved significantly. Partial PCL released can significantly improve the anteroposterior laxity and had less effect on the varus and valgus laxity, rotational laxity and maximum flexion angle. So, a knee that is tight in flexion can be more likely to be corrected by increasing posterior tibial slope than by partially releasing PCL.

Arthroplasty, Replacement, Knee ; Biomechanical Phenomena ; Cadaver ; Humans ; Knee Joint ; physiopathology ; surgery ; Posterior Cruciate Ligament ; physiopathology ; surgery ; Postoperative Period ; Range of Motion, Articular ; Tibia ; surgery

OBJECTIVETo compare the ability of three different reconstruction procedures in restoring the posterior displacement of tibia and the posterior stability of the knee joint from 0 degree to 120 degrees flexion.

METHODSThree posterior cruciate ligaments (PCL) reconstruction procedures were performed, namely two-band two-tunnel reconstruction, one-band anterior tunnel reconstruction and one-band posterior tunnel reconstruction. The posterior displacement of the tibia in relation to the femur was measured when a 200N posterior force was applied.

RESULTSWithin the flexion range of 0 degree to 30 degrees, the displacement in the one-band posterior tunnel reconstruction showed little difference from that of an intact knee (P>0.05). But when the flexion exceeded 30 degrees, especially when it exceeded 60 degrees, the displacement in one-band posterior tunnel reconstruction was much greater than that of an intact knee (P<0.01). In two-band two-tunnel reconstruction and one-band anterior tunnel reconstruction, the displacement was approximately the same as that of an intact knee ranging from 0 degree to 120 degrees (P>0.05), while a slight over-restriction might be found at some angles.

CONCLUSIONSTwo-band reconstruction could effectively restrict the posterior displacement of the tibia and restore anterior, posterior stability of the knee joint within its full range of flexion. One-band anterior tunnel reconstruction also could maintain the posterior stability of the knee, while the result of one-band posterior tunnel reconstruction is the most unsatisfactory.

Adult ; Biomechanical Phenomena ; Cadaver ; Humans ; Joint Instability ; surgery ; Knee Joint ; physiopathology ; Male ; Middle Aged ; Orthopedic Procedures ; Posterior Cruciate Ligament ; surgery ; Postoperative Period ; Range of Motion, Articular