Posterior Cruciate Ligament Deficient Knees Research Articles

Diagnostic Value of MRI and Radiographs of the Knee to Identify Osteochondral Lesions in Acute Patellar Instability.

The purpose of this study was to define the diagnostic value of magnetic resonance imaging (MRI) and plain radiographs (X-ray [XR]) in identifying an osteochondral defect or loose body in patients undergoing operative treatment for patellar instability. A total of 87 patients treated operatively for patellar instability with medial patellofemoral ligament (MPFL) reconstruction between 2015 and 2019 were identified. Inclusion criteria were evidence of clinical patellar instability, preoperative XR and MRI studies, and concomitant diagnostic knee arthroscopy and MPFL reconstruction performed to address patellar instability. Patients were excluded if they had a history of prior procedure for patellar instability on the surgical knee, underwent MPFL reconstruction without concomitant diagnostic knee arthroscopy, or had an anterior cruciate ligament or posterior cruciate ligament deficient knee. Operative notes and arthroscopic images were reviewed to identify osteochondral or chondral injuries and loose bodies noted during diagnostic arthroscopy. The primary outcome was the identification of intra-articular loose bodies, chondral injury, or osteochondral defect on preoperative plain radiographs and MRI in patients with patellar instability. All MRIs were performed on a 3T MRI. The sensitivity and specificity of identifying loose bodies on MRI were 0.52 and 0.92 and on XR were 0.23 and 0.98, respectively. The sensitivity and specificity of identifying osteochondral lesions on MRI were 0.43 and 0.81 and on XR were 0.08 and 0.97, respectively. Of the 87 available reports, 45 (51%) described performing chondroplasty for Outerbridge grade II/III chondral lesions on diagnostic arthroscopy. In conclusion, MRI and XR are poorly sensitive at identifying loose bodies or osteochondral defects after patellar dislocations. The poor sensitivity of imaging studies must be considered when determining whether or not to recommend operative management to a patient with patellar instability. This is a Level IV, diagnostic study.

Anterior Open-Wedge Osteotomy in Posterior Cruciate Ligament Deficient Knees: From a Historical Perspective to First Clinical Results.

Recently, the bony anatomy of the proximal tibia has gained strong interest, particularly in the cruciate ligament deficient knee. Regarding the anterior cruciate ligament (ACL), several studies outlined that a steep tibial slope (≥12 degrees) contributes to early failures after ACL reconstruction. As a consequence, the first clinical reports are available on slope reducing osteotomies in revision ACL surgery. Vice versa, biomechanical as well as clinical reports suggest that a flat slope increases the load on the posterior cruciate ligament (PCL) and might contribute to a poor result after PCL reconstruction. Since many decades, slope increasing anterior open wedge osteotomies are used to treat a symptomatic genu recurvatum. The aim of the current report is to describe different surgical techniques and report our first clinical experience of an anterior open wedge osteotomy as a sole procedure in chronic PCL deficient knees with a flat tibial slope. In six cases, a mean preoperative slope of 3.7 degrees (range = 2-5 degrees) was increased to a mean of 11.5 degrees (range = 9-13 degrees). There was one case with a delayed bone healing, which was successfully treated without loss of correction by revision internal fixation and bone grafting.

Biomechanical effect of tibial slope on the stability of medial unicompartmental knee arthroplasty in posterior cruciate ligament-deficient knees.

AimsUnicompartmental knee arthroplasty (UKA) has become a popular method of treating knee localized osteoarthritis (OA). Additionally, the posterior cruciate ligament (PCL) is essential to maintaining the physiological kinematics and functions of the knee joint. Considering these factors, the purpose of this study was to investigate the biomechanical effects on PCL-deficient knees in medial UKA.MethodsComputational simulations of five subject-specific models were performed for intact and PCL-deficient UKA with tibial slopes. Anteroposterior (AP) kinematics and contact stresses of the patellofemoral (PF) joint and the articular cartilage were evaluated under the deep-knee-bend condition.ResultsAs compared to intact UKA, there was no significant difference in AP translation in PCL-deficient UKA with a low flexion angle, but AP translation significantly increased in the PCL-deficient UKA with high flexion angles. Additionally, the increased AP translation became decreased as the posterior tibial slope increased. The contact stress in the PF joint and the articular cartilage significantly increased in the PCL-deficient UKA, as compared to the intact UKA. Additionally, the increased posterior tibial slope resulted in a significant decrease in the contact stress on PF joint but significantly increased the contact stresses on the articular cartilage.ConclusionOur results showed that the posterior stability for low flexion activities in PCL-deficient UKA remained unaffected; however, the posterior stability for high flexion activities was affected. This indicates that a functional PCL is required to ensure normal stability in UKA. Additionally, posterior stability and PF joint may reduce the overall risk of progressive OA by increasing the posterior tibial slope. However, the excessive posterior tibial slope must be avoided.Cite this article: Bone Joint Res 2020;9(9):593–600.

Association of ACL Laxity Tests with Arthroscopic Findings in Chronic ACL and PCL Deficient Knees.

An anterior cruciate ligament (ACL) injury may be diagnosed by clinical examination and radiological investigation using magnetic resonance imaging or by arthroscopy. 1,2 Based on our experience, the ACL tear in concomitant chronic ACL and posterior cruciate ligament (PCL) deficient knees may produce knee laxity, which is more difficult to assess on clinical examination, which in turn may affect the management algorithm of the patient. Our hypothesis is that, in a concomitant chronic ACL and PCL injury, posterior capsular contracture and abnormal reattachment of torn ACL will result in less clinical and subjective laxity, preoperatively. The aim of this study is to review a cohort of patients who had undergone PCL reconstructive surgery and compare the preoperative clinical assessments with and without anesthesia with arthroscopic finding of ACL. This is to assess the accuracy and reliability of clinical ACL laxity tests in detecting ACL tear in chronic ACL and PCL injury.

The necessity of clinical application of tibial reduction for detection of underestimated posterolateral rotatory instability in combined posterior cruciate ligament and posterolateral corner deficient knee.

The purpose of this study was to evaluate the usefulness of tibial reduction during dial test for clinical detection of underestimated posterolateral rotatory instability (PLRI) in combined posterior cruciate ligament (PCL)-posterolateral corner (PLC) deficient knee in terms of external rotation laxity and clinical outcomes. Twenty-one patients who classified as grade I PLRI using dial test with subluxated tibia, but classified as grade II with tibial reduction evaluated retrospectively. The mean follow-up was 39.3months (range 24-61months). Each patient was evaluated by the following variables: posterior translation and varus laxity on radiograph, KT-1000 arthrometer, dial test (reduced and subluxated position), International Knee Documentation Committee, Orthopädische Arbeitsgruppe Knie scoring system and Tegner activity scale. There were significant improvements in posterior tibial translation (8.6±2.0 to 2.1±1.0mm; P<0.001), varus laxity (3.3±1.3 to 1.4±0.5mm; P<0.001) and external rotation (13.2°±0.8° to 3.6°±1.1° at 30°, 13.3°±0.9° to 3.6°±0.9° at 90°; P<0.001). The clinical scores were improved significantly at the last follow-up (P<0.001). The external tibial rotation during dial test with tibial reduction increased from 6.8°±0.9 to 13.2°±0.8° at 30° of knee flexion, from 7.0°±0.8° to 13.3°±0.9° at 90° (P<0.001). The clinical application of reduction of posteriorly subluxated tibia during the dial test was essential for an appropriate treatment of underestimated PLRI in combined PCL-PLC deficient knee. Retrospective case series, Level IV.

Tibial Inlay Technique Using Hamstring Graft for Posterior Cruciate Ligament Reconstruction and Remnant Revision

The posterior tibial inlay technique is currently accepted as a standard operation for the posterior cruciate ligament–deficient knee. The classical technique requires a graft construct consisting of a bony part to be fitted into the posterior tibial socket. When an autogenous source is chosen, morbidity at the donor site generated by obtaining the graft with a bony part (e.g., bone–patellar tendon–bone or quadriceps tendon–bone) can be more serious than when obtaining the soft-tissue graft (e.g., hamstring). This study describes an alternative use of soft-tissue graft anchored in a bone socket at the posterior tibial margin by a transfixing cancellous screw. The graft is secured on top by a “bone washer” harvested from this bone socket to provide biological bone-tendon-bone healing. The posterior cruciate ligament remnant with integral fibers at the femur can have its tibial part revised, tensioned, and reattached concomitantly. This additional procedure is deemed to enhance joint stability and promote graft healing.

In Vivo Analysis of the Isolated Posterior Cruciate Ligament–Deficient Knee During Functional Activities

Background: Most patients with isolated posterior cruciate ligament (PCL) injuries have minimal symptoms, and nonoperative treatment is recommended. However, over time, these patients can develop significant degenerative changes in their knees. Historically, PCL laxity is graded by nonweightbearing anteroposterior measuring techniques that do not reproduce the true, dynamic weightbearing conditions in the injured knee. The purpose of this study was to determine the patholaxity in patients with isolated PCL deficiency during functional weightbearing activities (running, walking, and stair ascent). Hypothesis: Patients with unilateral, isolated PCL deficiency will demonstrate dynamic anteroposterior and rotational instability in their affected knees during functional activities of level running and stair ascent compared with their unaffected, contralateral knees. Study Design: Controlled laboratory study. Methods: Nine asymptomatic patients with isolated grade II PCL injury underwent Dynamic Stereo X-Ray (DSX) of both knees during level running and stair ascent. Three-dimensional reconstructions of the patients’ bilateral distal femurs and proximal tibias were created from high-resolution computed tomography (CT) scans. Three-dimensional joint kinematics were determined using a model-based tracking approach to align the radiographic images with CT-derived bone models. The resulting tibiofemoral rotations and translations for the PCL-deficient and PCL-intact knees were then compared. Results: During level running, the tibia of the PCL-deficient knee was approximately 2 mm posteriorly subluxated and had an anterior velocity relative to the femur approximately 40 mm/s greater than the contralateral, uninjured knee; however, this was only during the swing phase. No significant differences were found during the stance phase of running. During stair ascent, the tibia of the PCL-deficient knee was approximately 4 mm posteriorly subluxated compared with the intact limb during the terminal swing phase and early stance phase. Between foot strike and the time of peak ground-reaction force (GRF), the tibia of the PCL-deficient knee translated anteriorly relative to the femur with velocities 3 to 4 times greater than in the intact limb. Level walking was also evaluated in 3 patients, but no differences were seen, and it was not tested in the remaining 6 patients. Conclusion: Changes in knee kinematics due to isolated PCL injuries were highly activity dependent. During running, small differences were identified only during the swing phase when the knee was unloaded. However, during stair ascent, significant differences extended from the late swing into early stance phase. During the swing phase of stair ascent, the tibia in the PCL-deficient joint subluxated posteriorly. Then, as load was transferred to the ascending limb, the tibia reduced anteriorly with high velocity relative to the femur. The resulting shear motion may expose the loaded joint to abnormal and potentially damaging forces. Clinical Relevance: During functional activities, patients with isolated PCL injuries experience significant knee instability that cannot be identified by standard nonweightbearing static laxity measurements. The finding that different activities create different degrees of instability may have important implications for rehabilitation and activity limitations for PCL-deficient individuals.

Physical examination and in vivo kinematics in two posterior cruciate ligament retaining total knee arthroplasty designs

The aim of this study was to investigate anteroposterior instability in the CKS and the PFC total knee arthroplasty (TKA) designs. Physical examinations, including VAS, IKS and WOMAC were performed in combination with a detailed fluoroscopic measurement technique for three-dimensional kinematic assessment of TKA design function. Anteroposterior instability rated with the IKS was not significantly different ( p = 0.34), but patients with a CKS design showed more limitations according to the WOMAC joint stiffness total score, and for items regarding higher flexion activities in the WOMAC score for knee disability. Kinematic analyses showed that the CKS design tended to have more anterior sliding of the femur on the tibia during mid- and deep flexion activities. The sliding distance was larger at the medial than at the lateral side. This phenomenon has also been described for posterior cruciate ligament deficient knees. Furthermore, the CKS design showed a significantly lower range of tibial rotation ( p < 0.05) from maximum extension to maximum flexion during deep knee bend activities. Kinematic differences can be ascribed to posterior cruciate ligament deficiency/laxity or differences in TKA designs.

Quadriceps force in relation of intrinsic anteroposterior stability of TKA design

Decreased quadriceps strength and fatigue is suspected to be one of the contributing factors for anterior knee pain and malfunction after total knee arthroplasty (TKA). The purpose of this in vitro study was to investigate the amount of quadriceps force required to extend the knee isokinetically after TKA in dependence of different prosthesis designs and the state of the posterior cruciate ligament (PCL). Eight fresh frozen human knee specimens underwent testing in a kinematic device simulating an isokinetic knee extension cycle from 120° of flexion to full extension. The quadriceps force was measured after implantation of a cruciate retaining (CR) TKA (Genesis II, Smith&Nephew, Memphis, TN, USA) applying a conventional CR (11 mm) and a highly conforming (deep dished, DD) polyethylene (PE) inlay consecutively before and after resection of the PCL. Finally, tests were repeated with a posterior-stabilized (PS) design. Simulating a physiological knee extension, no significant differences in the average quadriceps force were detected between the cruciate preserving inlays (CR 1,146.57 ± 88.04 N, DD 1,150.19 ± 97.54 N, P = 0.86) as long as the PCL was intact. After resection of the PCL, the required quadriceps force increased significantly for both designs (CR 1,203.17 ± 91.51 N, P < 0.01 and DD 1,191.88 ± 80.07 N, P < 0.03). After implantation of the posterior stabilized femoral component quad force decreased to its initial levels with forces significantly lower compared to the PCL deficient knees provided with a CR or DD (PS 1,130.91 ± 107.88 N, P < 0.01) inlay. With a deficient PCL there were no statistical differences for the DD design in comparison with CR in mean quad forces (CR 1,203.17 ± 91.51 N vs. DD 1,191.88 ± 80.07 N, P = 0.50) nor in peak forces (CR 1,729.44 ± 161.86 N, DD 1,688.66 ± 123.18 N, P = 0.17). At intact PCL peak quad forces and mean forces beyond 70° of flexion could be shown to be significantly lower with a PS TKA design in comparison with cruciate preserving designs such as CR and DD. In the PCL deficient knee quad forces with a highly conforming implant (DD) and CR were significantly higher than with a PS TKA. The use of PS implants in all PCL deficient knees seems to be advisable

Analysis of Tibiofemoral Cartilage Deformation in the Posterior Cruciate Ligament-Deficient Knee

Degeneration of the tibiofemoral articular cartilage often develops in patients with posterior cruciate ligament deficiency, yet little research has focused on the etiology of this specific type of cartilage degeneration. In this study, we hypothesized that posterior cruciate ligament deficiency changes the location and magnitude of cartilage deformation in the tibiofemoral joint. Fourteen patients with a posterior cruciate ligament injury in one knee and the contralateral side intact participated in the study. First, both knees were imaged with use of a specific magnetic resonance imaging sequence to create three-dimensional knee models of the surfaces of the bone and cartilage. Next, each patient performed a single leg lunge as images were recorded with a dual fluoroscopic system at 0 degrees, 30 degrees, 60 degrees, 75 degrees, 90 degrees, 105 degrees, and 120 degrees of knee flexion. Finally, the three-dimensional knee models and fluoroscopic images were used to reproduce the in vivo knee position at each flexion angle with use of a previously described image-matching method. With use of these series of knee models, the location and magnitude of peak tibiofemoral cartilage deformation at each flexion angle were compared between the intact contralateral and posterior cruciate ligament-deficient knees. In the medial compartment of the posterior cruciate ligament-deficient knees, the location and magnitude of peak cartilage deformation were significantly changed, compared with those in the intact contralateral knees, between 75 degrees and 120 degrees of flexion, with a more anterior and medial location of peak cartilage deformation on the tibial plateau as well as increased deformation of the cartilage. In the lateral compartment, no significant differences in the location or magnitude of peak cartilage deformation were found between the intact and posterior cruciate ligament-deficient knees. The altered kinematics associated with posterior cruciate ligament deficiency resulted in a shift of the tibiofemoral contact location and an increase in cartilage deformation in the medial compartment beyond 75 degrees of knee flexion. The magnitude of the medial contact shift in the posterior cruciate ligament-deficient knee was on the same order as that of the anterior contact shift.

Posterior Tibial Slope After Medial Opening Wedge High Tibial Osteotomy of the Varus Degenerative Knee

This study examined whether medial opening wedge osteotomy inadvertently changes posterior tibial slope and whether this change affects range of motion and functional outcomes. Lateral radiographs of 82 knees with varus arthrosis were reviewed to measure posterior tibial slope before and after medial opening wedge high tibial osteotomy. Anterior or posterior cruciate ligament-deficient knees were excluded. Twenty-one osteotomies were performed using distraction osteogenesis/medial external fixator, 26 using acute distraction/Arthrex plate fixation, and 35 using acute distraction/EBI plate fixation. Preoperative and postoperative Lysholm scores and range of motion were recorded. Posterior slope increased from a mean of 12.5 degrees preoperatively to 16.5 degrees postoperatively (P<.01). Fixation types revealed no difference in posterior slope change. Large slope changes had less preoperative knee flexion than did small changes (123 versus 131; P=.012). No significant correlation existed between posterior slope change and postoperative Lysholm scores (r=0.047, P>.05). We found that medial opening wedge osteotomy may alter sagittal alignment by increasing posterior tibial slope.

The Role of the Posterior Oblique Ligament in Controlling Posterior Tibial Translation in the Posterior Cruciate Ligament-Deficient Knee

Background Posterior cruciate ligament injuries are often associated with injuries to other structures. The role of the posteromedial structures of the knee in these injuries has received little attention. Hypothesis The posterior oblique ligament is an important restraint to posterior tibial translation in the posterior cruciate ligament–deficient knee. Study Design Controlled laboratory study. Methods Kinematic studies were performed on 10 cadaveric knees to test 3 external loading conditions at 0°, 30°, 60°, and 90° of flexion (134 N posterior tibial load, 10 N·m valgus rotation, and 5 N·m internal rotation). Resulting posterior tibial translation was determined by using a robotic/universal force-moment sensor testing system for (1) intact, (2) posterior cruciate ligament–deficient, (3) posterior cruciate ligament/superficial medial collateral ligament–deficient, (4) posterior cruciate ligament/superficial medial collateral ligament/deep medial collateral ligament/posterior oblique ligament–deficient, and (5) posterior cruciate ligament/superficial medial collateral ligament/deep medial collateral ligament/posterior oblique ligament/posteromedial capsule–deficient knee. Results When both the superficial medial collateral ligament and deep medial collateral ligament were cut in the posterior cruciate ligament–deficient knee, posterior tibial translation did not increase significantly at any flexion grade under all external loading conditions (P > .05). Additional cutting of the posterior oblique ligament increased posterior tibial translation significantly at 0°, 30°, 60°, and 90° of flexion under posterior tibial load and at all flexion angles tested under valgus or internal tibial load (P < .05). Additional cutting of the posteromedial capsule increased posterior tibial translation only at 0° and 30° in response to a valgus and internal tibial load (P < .05). Conclusion The posterior oblique ligament and posteromedial capsule have a significant role in the prevention of additional posterior tibial translation in the knee with posterior cruciate ligament injury. Clinical Relevance The posterior oblique ligament should be addressed in the patient with combined injuries to the posterior cruciate ligament and the posteromedial structures.

Accuracy of Stress Radiography Techniques in Grading Isolated and Combined Posterior Knee Injuries

Background Stress radiography techniques have been shown to be superior to the arthrometer and clinical examination in evaluating the posterior cruciate ligament—deficient knee, but no precise relationship has been established between the extent of the lesion and the laxity measured by stress radiography. Hypothesis It is possible to establish a precise relation between posterior laxity and the anatomical lesions of the posterior cruciate ligament and posterior structures using stress radiography. Study Design Controlled laboratory study. Methods Measurements were performed on 15 fresh-frozen cadaveric knee specimens. A partial posterior cruciate ligament lesion was created by sectioning the anterolateral bundle, followed by a complete section. Then the lateral collateral ligament and the posterolateral corner were transected, and finally the medial collateral ligament and the posteromedial corner were sectioned. Stress radiography was performed first on the intact knee and again after each lesion was created using 4 techniques: Gravity Sag View, PCL-Press, Telos at 80°, and Telos at 30° of flexion. Results Telos 30 and Telos 80 revealed the best overall performance as a diagnostic test in terms of accuracy in discriminating between the different types of lesions. Using the Telos device, we determined the following cut-off points: for a partial lesion, less than 3 mm at 30° and less than 6 mm at 80°; for a complete lesion, between 4 mm and 9 mm at 30° and between 7 mm and 12 mm at 80°; for associated peripheral lesions, more than 9 mm at 30° and more than 12 mm at 80°. Conclusion The Telos 30° and 80° allow us to accurately distinguish between the different types of lesion and permit grading of posterior knee laxity. Clinical Relevance Stress radiography allows characterization of posterior knee injuries and helps to determine treatment strategy.

Importance of Tibial Slope for Stability of the Posterior Cruciate Ligament—Deficient Knee

Background Previous studies have shown that increasing tibial slope can shift the resting position of the tibia anteriorly. As a result, sagittal osteotomies that alter slope have recently been proposed for treatment of posterior cruciate ligament (PCL) injuries. Hypotheses Increasing tibial slope with an osteotomy shifts the resting position anteriorly in a PCL-deficient knee, thereby partially reducing the posterior tibial “sag” associated with PCL injury. This shift in resting position from the increased slope causes a decrease in posterior tibial translation compared with the PCL-deficient knee in response to posterior tibial and axial compressive loads. Study Design Controlled laboratory study. Methods Three knee conditions were tested with a robotic universal force-moment sensor testing system: intact, PCL-deficient, and PCL-deficient with increased tibial slope. Tibial slope was increased via a 5-mm anterior opening wedge osteotomy. Three external loading conditions were applied to each knee condition at 0°, 30°, 60°, 90°, and 120° of knee flexion: (1) 134-N anterior-posterior (A-P) tibial load, (2) 200-N axial compressive load, and (3) combined 134-N A-P and 200-N axial loads. For each loading condition, kinematics of the intact knee were recorded for the remaining 5 degrees of freedom (ie, A-P, medial-lateral, and proximal-distal translations, internal-external and varus-valgus rotations). Results Posterior cruciate ligament deficiency resulted in a posterior shift of the tibial resting position to 8.4 ± 2.6 mm at 90° compared with the intact knee. After osteotomy, tibial slope increased from 9.2° ± 1.0° in the intact knee to 13.8° ± 0.9°. This increase in slope reduced the posterior sag of the PCL-deficient knee, shifting the resting position anteriorly to 4.0 ± 2.0 mm at 90°. Under a 200-N axial compressive load with the osteotomy, an additional increase in anterior tibial translation to 2.7 ± 1.7 mm at 30° was observed. Under a 134-N A-P load, the osteotomy did not significantly affect total A-P translation when compared with the PCL-deficient knee. However, because of the anterior shift in resting position, there was a relative decrease in posterior tibial translation and increase in anterior tibial translation. Conclusion Increasing tibial slope in a PCL-deficient knee reduces tibial sag by shifting the resting position of the tibia anteriorly. This sag is even further reduced when the knee is subjected to axial compressive loads. Clinical Relevance These data suggest that increasing tibial slope may be beneficial for patients with PCL-deficient knees.

The nonoperative treatment of acute, isolated (partial or complete) posterior cruciate ligament-deficient knees: an intermediate-term follow-up study.

Fifty-seven consecutive patients (58 knees) with an acute, isolated, posterior cruciate ligament (PCL) injury were treated nonoperatively. Clinical, radiographic, and functional assessment was performed at a mean follow-up of 6.9 years (range 2 to 19.3 years) after the initial diagnosis. At the time of initial documentation of the injury, the posterior drawer test was grade A in 17 knees and grade B in 41 knees. The mean preinjury Tegner activity level was 7 (range 4 to 10). At latest follow-up, 38 knees had no pain, 14 had mild pain, and 6 had moderate pain on exertion. Fifty-four knees had no swelling, 3 had mild, intermittent swelling, and 1 had a moderate swelling on exertion. The posterior drawer test was grade A in 14 knees and grade B in 44 knees. The mean Lysholm-II knee score was 85.2 points (range 51 to 100 points) and the mean Tegner activity level was 6.6 (range 3 to 10). Based on Lysholm-II knee scoring system, the results were excellent in 23 knees (40%), good in 30 knees (52%), fair in 2 knees (3%), and poor in 3 knees (5%). No statistically significant correlation (p = 0.097) was seen between the grade of PCL laxity and Lysholm-II knee score. Plain radiographs showed mild (grade I) medial compartment osteoarthritis (OA) in 7 knees, and moderate (grade II) medial compartment OA in 3 knees. Mild patellofemoral OA was seen in 4 knees. We believe that most patients with acute, isolated PCL injuries do well with nonoperative treatment at a mean follow-up of 6.9 years. The level of evidence for this retrospective cohort study is level III.

Posterior instability near extension is related to clinical disability in isolated posterior cruciate ligament deficient patients

The purpose of this study is to evaluate the relationship between the magnitude of knee laxity and posterior instability at different knee flexion angles and clinical disability in isolated posterior cruciate ligament (PCL) deficient patients. Knee laxity at 20 degrees and 70 degrees of knee flexion were evaluated using KT-2000 arthrometer, and the posterior instability at 20 degrees , 45 degrees and 90 degrees of flexion were evaluated using stress radiography. We assessed the differences in the knee laxity and the tibial translation between isolated PCL deficient knees and normal knees, and between the patients with giving-way during activities of daily living (ADL) and without giving-way. There were statistical differences in the knee laxity and the tibial translation at all knee flexion angles between the PCL deficient knees and normal knees. The magnitude of the knee laxity at 20 degrees of flexion measured with KT-2000 arthrometer was significantly larger in the patients with giving-way than those in the patients without giving-way although there was no significant difference in the tibial translation at 70 degrees between the two groups. The tibial translation in both medial and lateral compartments at 20 degrees and 45 degrees measured with stress radiography were significantly larger in the patients with giving-way than those in the patients without giving-way although there was not significant difference at 90 degrees between the two groups. These results suggested that the magnitude of the knee laxity and the posterior tibial translation at shallow knee flexion angles would be related to giving-way during ADL in isolated PCL deficient patients.

Clinical disability in posterior cruciate ligament deficient patients does not relate to knee laxity, but relates to dynamic knee function during stair descending

We investigated the factors which influence clinical subjective symptoms during activities in Posterior cruciate ligament (PCL) deficient patients by evaluating knee laxity, muscle strength and knee mechanics during level walking, stair ascent and descent. Twenty-two subjects with isolated PCL deficient knees and 20 healthy volunteers were involved. The PCL deficient patients were divided into two subgroups based on previous history of experiencing giving-way during stair descent; a giving-way group (10 subjects) and a nongiving-way group (12 subjects). Giving-way during activities of daily living is a key symptom in isolated PCL deficient patients. No statistically significant differences in the knee laxity, muscle strength and knee mechanics during level walking and were observed between the giving-way group and the nongiving-way group. However, we found significant differences in the knee mechanics during stair ascent and descent between the two groups, and these differences were more remarkable during stair descent. Peak values of knee flexion angle, external knee flexion moment and posterior knee force during early stance phase were significantly lower in the giving-way group than in the nongiving-way group. This study indicated that the symptom of giving-way during stair descent was related to knee mechanics during stair descent, unlike other quantitative evaluations such as KT-2000 or Biodex.

Anatomical Posterior Cruciate Ligament Transplantation

Background Although current techniques of posterior cruciate ligament reconstruction may successfully stabilize the posterior cruciate ligament-deficient knee, no studies have demonstrated restoration of intact-knee kinematics. Hypothesis Posterior cruciate ligament transplantation will successfully restore posterior stability and kinematics to the posterior cruciate ligament-deficient knee. Study Design Controlled laboratory study. Methods Seven pairs (donor/recipient) of size-matched cadaveric knees underwent a novel technique for posterior cruciate ligament transplantation. The grafts were fixed at the femoral origin and tibial insertion using an inlay technique with rigid fixation. The knees were tested in the intact (intact group), posterior cruciate ligament-deficient (deficient group), and posterior cruciate ligament-transplanted (transplant group) states. A 3-dimensional electromagnetic tracking system during an active knee extension and passive knee flexion maneuver was used to quantify kinematics, specifically looking at femoral rollback. KT ligament arthrometry was used to quantify posterior stability at the quadriceps neutral angle (70°). Results For femoral rollback, the intact versus deficient groups was significantly different (P = .045) as was deficient versus transplant groups (P = .008) but not intact versus transplant groups. Similar differences were noted with the measurements of posterior stability (P < .001). Total posterior laxity between the intact versus deficient groups was significantly different (means, 1.32 mm vs 11.1 mm; P < .0001), as was deficient versus transplant groups (means, 11.1 mm vs 2.04 mm; P< .126) but not intact versus transplant groups. Conclusion In a posterior cruciate ligament-deficient cadaveric model, we demonstrated the technical feasibility and efficacy of posterior cruciate ligament transplantation for restoring femoral rollback and posterior stability at the quadriceps neutral angle. Clinical Relevance Future studies in posterior cruciate ligament reconstruction should not only address stability but also restoration of normal knee kinematics in assessing the success of a given technique.

Diagnostik und Therapie von Verletzungen des hinteren Kreuzbandes

Over the last few years, the posterior cruciate ligament (PCL) has taken over from the anterior cruciate ligament (ACL) as the new challenge in knee diagnosis and treatment. PCL injuries are much more frequent than previously thought. Despite increasing experience, we are often still confronted with an inappropriate and delayed diagnosis of this injury and its concomitant lesions. Additionally, the outcome of surgical treatment has not yet reached an acceptable rate of satisfaction. Therefore, the goal of this concept review is to give a comprehensive insight into injury mechanisms, diagnostics and treatment regimes based on our experience and data from the international literature. Furthermore, diagnostic problems with respect to clinical examination and imaging techniques are discussed. We also present a differential concept for the perioperative and conservative management of PCL deficient knees in order to adequately address concomitant injuries such as posterolateral rotatory instability and combined ACL injuries, with the aim of further improving results.

The Arthroscopic Appearance of a Normal Anterior Cruciate Ligament in a Posterior Cruciate Ligament–Deficient Knee: The Posterolateral Bundle (PLB) Sign

Partial anterior cruciate ligament (ACL) tears that result in functional instability are usually the result of a deficiency of the anteromedial bundle (AMB), and are evident arthroscopically by a prominent posterolateral bundle (PLB). As double-bundle ACL reconstructions are being suggested to recreate a more normal anatomy, the roles of each bundle are being more critically questioned. We present a case that describes the appearance of a normal ACL in a posterior cruciate ligament (PCL)-deficient knee in which the PLB of the ACL is prominent, giving the appearance of a complete tear of the AMB of the ACL, and scarring of this bundle to the PCL stump. On further inspection, and when the tibia was reduced, the normal appearance of the ACL returned, with visualization of the AMB obscuring the PLB. We have named this arthroscopic finding the “PLB sign.” This finding confirms the individual roles of each bundle of the ACL. It is important to not misinterpret this abnormal appearance of the ACL as a partial ACL tear in a PCL-deficient knee.