A Comparative Study on Correlation between Magnetic Resonance Imaging and Arthroscopic Findings in the Knee Joint Injuries.

Introduction: The knee joint primarily allows for flexion and extension and is essentially a hinge joint. The knee joint, like all hinge joints, is strengthened by collateral ligaments - one on each side of the joint. Objective: Our study sought to investigate potential correlations between arthroscopy and magnetic resonance imaging (MRl) examination in the diagnosis of traumatic diseases of the knee. Methods and Materials: A prospective study was conducted on 30 persons who showed signs of having traumatic knee disease. Following a comprehensive evaluation of the patient s medical history and current state of health, we opted to undergo an arthroscopic evaluation and knee MRL. Results: The sensitivity of the MRI was 93.87%, the specificity was 91.54%, the accuracy was 92.50%, and the negative predictive value was 95.58% when compared to arthroscopic inspection as the gold standard. Conclusion: This study demonstrates that MRIs frequently misdiagnose individuals with multiple knee injuries or fail to detect a lesion while doing a diagnostic evaluation. Therefore, if the MRI comes out normal, there is no reason to deny the patient arthroscopy. Due to this MRI flaw, researchers have determined that arthroscopy can be performed following a comprehensive clinical assessment without the need for an MRI.

PCL injury following high energy trauma: associated injuries and postoperative complications "insights from a national registry study".

PURPOSE: The posterior cruciate ligament (PCL) is a vital knee stabilizer. While PCL injuries are rare, high-energy traumas can lead to total ruptures, with accompanying injuries requiring surgery. This study aims to investigate the demographics, concomitant injuries, and postoperative complications of patients who underwent PCL reconstruction due to high-energy trauma in a large patient sample. METHODS: Patients who underwent PCL reconstruction from 2016 to 2022 were retrospectively evaluated using data from a nationwide personal health recording system. Patient demographics, injury mechanisms, associated fractures, soft tissue injuries, and postoperative complications were collected from patient notes, clinical visits, and surgical notes. Individuals with a PCL injury following high-energy trauma (car accident, falls from height, motorcycle accident) with a minimum follow-up of 1 year were included in the study. RESULTS: The study included 416 patients with a mean age of 32.4 years. Isolated PCL injuries (n = 97, 23.3%) were observed less frequently than multiple-ligament injuries (n = 319, 76.7%). Most cases were treated with single-stage surgery (86.8%), while staged surgeries were performed in a minority of cases (13.2%). There was no relationship between trauma mechanisms and multiple-ligament involvement, accompanying injuries, or postoperative complications. Surgeries following car accidents were more likely to occur as staged surgeries (p = 0.014). Additionally, the complication rates for staged surgeries and younger patients (≤ 18 years) were significantly higher (p = 0.009). CONCLUSION: High-energy trauma-induced PCL injuries are often associated with severe concurrent knee injuries with multiple ligament involvement. PCL reconstructions following car accidents are more likely to be staged. These findings highlight the importance of careful consideration in managing these cases to minimize complications, particularly in younger age groups. LEVEL OF EVIDENCE: Level III.

Open Repair of Posterior Cruciate Ligament Tibial Bony Avulsion With Metal Anchor: A Case Report.

Introduction: The posterior cruciate ligament (PCL) is the largest and strongest intra-articular ligament of the knee joint and the primary posterior stabilizer. PCL injuries are less frequent than other knee ligament injuries and are typically combined with meniscal and chondral injuries or in the context of multiligamentous injuries. It is critical to properly diagnose and treat these lesions in order to avoid the risk of PCL insufficiency, subsequent knee instability, and early osteoarthritis. Surgical management can vary, and the ideal fixation device is still debated. Suture anchors are an unusual mean of fixation of PCL tibial bony avulsion. We report on two patients treated with open anchor fixation for PCL tibial bony avulsion with a follow-up of 3 years. Case Presentation: A 15-year-old male and a 65-year-old male were treated with open anchor fixation for bony tibial avulsion of the PCL. Surgical treatment was performed at 5 weeks and 3 weeks after the trauma, respectively. Diagnosis was made with an X-ray followed by CT and MR scans. Repair was achieved by reinserting the PCL bony fragment to its posterior tibial eminence with suture anchors through an open posterior approach. Both patients recovered full knee stability and a pain-free full range of motion (ROM) within 4 months and returned to their previous activities with a high satisfaction. The patient has been followed up for 3 years, and no complications were observed. Conclusion: PCL bony avulsions are rare, and their optimal treatment remains a significant subject of debate, particularly in the skeletally immature patient. We believe that open repair with metal anchors could be a good choice to repair PCL bony tibial avulsion in patients without concomitant intra-articular lesions and immature growth plates or severe fragmentation.

Outcome Analysis of Arthroscopic Fixation of Posterior Cruciate Ligament Avulsion Fracture Using a Single Tibial Tunnel and Suture Loop with Button Configuration - A Case Series Study.

Introduction: A prospective case series study to analyze the outcome of arthroscopic fixation of posterior cruciate ligament (PCL) avulsion fracture using a single tibial tunnel and suture loop with button configuration technique. PCL avulsion fracture injury requires surgical treatment to restore PCL function and stability of the knee joint. Several open and arthroscopic procedures require a steep learning curve are followed to treat these injuries; yet, our technique is a simpler technique with desirable outcomes and does not require a long learning curve. Hence, it is reported. Case Series: Ten patients with the same ethnic background having avulsed PCL injury since 2015 underwent arthroscopic fixation of avulsed PCL with single tibial tunnel and suture loop with button configuration within 3 months of injury are studied prospectively till date. All patients are clinically and radiologically evaluated with varied parameters. Postoperatively structured rehabilitation protocol is followed for all the patients. Post-operative clinical and radiological assessments are done and analyzed in 6 weeks, 3 months, 6 months, 1 year, 2 years, and 3 years. Discussion: Ten patients were available for follow-up for a period of 6 months-3 years. Outcome analysis at the end of 3 years for all patients showed definitive improvement in the function of the knee statistically and functionally. Conclusion: For patients with PCL avulsion fracture, arthroscopic fixation of PCL with a single tibial tunnel and suture loop with Endobutton configuration gives definitive results. Medium-term follow-up analysis shows no failure in the outcome.

Clinical and Functional Results Following Posterior Cruciate Ligament Reconstruction in Young Patients.

INTRODUCTION:  Posterior cruciate ligament injuries are uncommon, and their management is controversial. However, surgical reconstruction is necessary in case of symptomatic lesions. The present study aimed to analyse patients' reported outcomes and clinical evaluation after isolated posterior cruciate ligament reconstruction. MATERIALS AND METHODS:  The present study includes 12 patients with posterior cruciate ligament rupture. All patients were treated with arthroscopic surgery using single-bundle hamstring autograft ligament reconstruction. The primary outcome was the International Knee Documentation Committee (IKDC) subjective questionnaire; secondary outcomes included the Lysholm score and stability assessment.  Results: At the time of the surgery, the mean age of the study population was 24 years (range: 18-29), with a body mass index (BMI) of 23.2 kg/m2 (range: 21-25), and the mean time from injury was five months (range: 1-8). The follow-up period was at least 24 months. The mean IKDC score significantly increased from 68.0 preoperatively to 92.6 at the final follow-up. The Lysholm score also increased from 68.8 to 95.8. Knee stability was classified as normal in all patients after surgery. CONCLUSION:  The results of this study indicate that the posterior cruciate ligament reconstruction with single-bundle hamstring autograft is an efficient treatment option for managing symptomatic young patients. All patients presented good functional and clinical results at two years of follow-up. However, further studies with more participants and a longer follow-up are needed to validate these data.

Return to Play after Posterior Cruciate Ligament Injuries.

PURPOSE OF REVIEW: Posterior cruciate ligament injuries can be treated conservatively with a structured rehabilitation program or with surgical reconstruction. Treatment algorithms are based on a variety of factors including the patient's presentation, physical exam, and desired level of activity. The goal is to return the patient to their athletic pursuits with a stable and pain-free knee. Return to play and activities should be individualized based on the patient's injury and progression through rehabilitation. This article provides a review of the current treatments for posterior cruciate ligament injuries and the respective rehabilitation protocols, outcomes after each treatment option, and specific return to play criteria. RECENT FINDINGS: Current research shows excellent outcomes and return to play with conservative treatment of isolated posterior cruciate ligament injuries. Return to play algorithms stress the importance of quadriceps strengthening throughout the recovery process and emphasize inclusion of plyometrics and sport-specific training. Rehabilitation plays a critical role in the outcome after posterior cruciate ligament injury and the ability to return to athletics. The primary focus of post-injury or post-operative rehabilitation is to restore function, as it relates to range of motion, strength, and proprioception, while mitigating swelling and pain. The patients' desired sport and level of play dictate return to play timelines. The literature supports the use of non-operative management of isolated PCL injuries in athletes and non-athletes with excellent functional and patient-reported outcomes.

Single-stage arthroscopic-assisted treatment of anteromedial tibial plateau fracture with posterolateral corner injury: a retrospective study.

BACKGROUND: Anteromedial tibial plateau fracture with posterolateral corner (PLC) injury is a relatively rare combined injury in the clinic. In addition, there is no unified treatment scheme for this combined injury. The purpose of this study was to evaluate the clinical and imaging results of single-stage arthroscopic-assisted surgery for anteromedial tibial plateau fracture with PLC injury, and to explore the advantages of this surgical technique. METHOD: In this retrospective study, a total of 9 patients (7 males and 2 females) were included, aged 24-64 years (average 40.7 years), treated in our Department of Orthopedics from January 2016 to January 2021. In the preoperative evaluations, there were 9 cases of anteromedial tibial plateau fractures with PLC injuries, 6 cases of concomitant PCL injuries, 6 cases of concomitant medial or lateral meniscus injuries, and 2 cases of concomitant fibular head avulsion fractures. All patients underwent single-stage arthroscopic-assisted surgery. RESULTS: All patients were followed up, and the average follow-up period was 15.2 months (range 12-18 months). The average operation time was 135.6 min (range 100-160 min), and the average surgical blood loss was 87.2 ml (range 60-110 ml). The anatomical reduction was achieved in 9 cases, and the anatomical reduction rate was 100%. The average fracture healing time was 13.1 weeks (range 12-16 weeks). At the last follow-up, the average VAS score was 1 (range 0-2); the average Lysholm function score was 90.7 (range 86-95), and the average IKDC score was 91.4 (range 88-95); the average knee extension angle of all patients was 0° and the average knee flexion angle was 128.3° (average 120-135°); The posterior drawer test, the Lachman test and the dial test were negative for all cases. None of the patients had operation-related complications. CONCLUSION: Single-stage arthroscopy-assisted surgery in the treatment of anteromedial tibial plateau fracture with PLC injury can achieve good clinical outcomes, restore the stability of the knee joint, and reduce the risk of severe lower extremity dysfunction.

[Effectiveness analysis of arthroscopic reconstruction of posterior cruciate ligament with embedded "tibial tendon bolt" fixation].

Objective: To evaluate the effectiveness of arthroscopic reconstruction of posterior cruciate ligament (PCL) with embedded "tibial tendon bolt" fixation. Methods: The clinical data of 32 patients who underwent arthroscopic reconstruction of PCL using embedded "tibial tendon bolt" fixation through the tibial "8"-shaped tunnel between February 2012 and April 2016 were analyzed retrospectively. There were 23 males and 9 females, aged 15-57 years (mean, 39.9 years). The causes included traffic accident injury in 12 cases and sports injury in 20 cases. The clinical manifestations were swelling of knee joint, tenderness of knee joint space, and (+) Ⅲ degree in posterior drawer test; McMurry test (+) in 13 cases, valgus stress test (+) in 8 cases, Lachman test (+) in 9 cases, and Dial test (+) in 2 cases. The preoperative Lysholm score was 18.8±10.9, the International Knee Documentation Committee (IKDC) score was 18.0±15.2, and the detection value of KT-1000 was (14.34±2.73) mm. The time from injury to operation was 8-225 days, with a median of 11 days. Results: All 32 patients were followed up 25-36 months, with an average of 26.4 months. The patients had no tenderness of joint space, and the McMurry tests were all (-). At last follow-up, the Lysholm score and IKDC score were 90.2±2.4 and 87.2±6.2, respectively, which were significantly improved when compared with preoperative ones (t=-38.400, P<0.001; t=-27.190, P<0.001). The results of posterior drawer test were (-) in 21 cases, (+) Ⅰ degree in 9 cases, and (+) Ⅱ degree in 2 cases. At 1 and 2 years after operation, the detection value of KT-1000 were (5.56±2.28) mm and (5.87±1.78) mm, respectively, which were significantly improved when compared with preoperative values (P<0.05). Conclusion: The application of arthroscopic reconstruction of PCL using embedded "tibial tendon bolt" fixation through the tibial "8"-shaped tunnel is an effective, simple, and safe surgical procedure.

Clinically Reliable Knee Flexion Angle Measured on Stress Radiography for Quantifying Posterior Instability in Posterior Cruciate Ligament Injury.

BACKGROUND: After posterior cruciate ligament injury, stress radiography is a common method of quantifying posterior instability, defined as the side-to-side difference in posterior tibial displacement (PTD) between the injured knee and contralateral noninjured knee. However, no study has evaluated the reliability of PTD according to knee flexion angle (KFA) measurements on stress radiographs. PURPOSE: To evaluate the test-retest reliability of stress radiographic measurements of the KFA in the noninjured knee. In addition, we established a reliable range of KFAs to indicate posterior instability by comparing results with the instability measured at 90° KFA, which is considered the gold standard. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 3. METHODS: We evaluated patients who had undergone bilateral stress radiographic examinations at least 5 times for ligament injuries between January 2013 and November 2019. All examinations were performed on a Telos device with a 150-N posterior load. A total of 120 knees and 644 stress radiographs were enrolled. We measured the KFA and PTD on stress radiographs and evaluated the reliability of repeated PTD measurement and the correlation between KFA and PTD. RESULTS: The distribution of the actual noninjured knee KFA ranged from 56.9° to 106.7°. Among the 644 radiographs, 155 (24.1%) showed KFAs between 85° and 95°, and 287 (44.6%) showed KFAs between 80° and 85°. A significant correlation was found between KFA and PTD (P < .001), and the intrapatient intraclass correlation coefficient (ICC) was 0.788. A KFA range of 85° to 92° satisfied the criteria of high ICC (0.885) and nonsignificant correlation between KFA and PTD (P = .055) and thus was considered a reliable range of KFAs for quantifying posterior instability. We found no significant risk factors for measurement error, including age (P = .674), sex (P = .328), height (P = .957), weight (P = .248), or body mass index (P = .257). CONCLUSION: We found high reproducibility of posterior displacement measurements on Telos stress radiography at a KFA of 85° to 92° in noninjured knees.

Posterior cruciate ligament injury: Diagnosis, treatments and rehabilitation strategies / 中国组织工程研究

BACKGROUND: With the increasing cases of posterior cruciate ligament injury, there are endless protocols for diagnosing and treating posterior cruciate ligament injury. However, there are few reviews of the integrity of posterior cruciate ligament. OBJECTIVE: To complete a comprehensive review of posterior cruciate ligament injury in terms of anatomy, clinical manifestations, auxiliary examination, treatment methods and rehabilitation strategies. METHODS: The PubMed, Ovid, CKNI, and WanFang databases were retrieved using the key words of “posterior cruciate ligament, PCL, anatom*, diagnos*, treatments, surger*, rehabilitation.” A total of 223 articles were searched. After removal of repetitive and ineligible literature, 65 articles were included for review. RESULTS AND CONCLUSION: Missed diagnosis and misdiagnosis of posterior cruciate ligament injury certainly exist. Posterior cruciate ligament injuries are mostly caused by traffic injuries and sports injuries, and are accompanied by other structural injuries to a certain degree. A full understanding of patient’s medical history, accurate physical examination methods, and sophisticated auxiliary examinations can help to correctly identify injuries to the posterior cruciate ligament and the surrounding structures, so as to formulate a reasonable diagnosis and treatment protocol. Research suggests that patients with posterior cruciate ligament injury should be subjected to reconstruction of the posterior cruciate ligament as soon as possible to reduce the risk of further degeneration. At present, there are still large disagreements on the diagnosis, treatment methods, and rehabilitation strategies of posterior cruciate ligament injury. So, a large number of rigorous randomized controlled trials are urgently needed to select the most suitable diagnosis and treatment methods.

Reverse Segond Fracture without Posterior Cruciate Ligament Injury - A report of Two Cases and Review of the Literature.

INTRODUCTION: Reverse Segond fracture is a cortical avulsion fracture off the medial tibial plateau of the knee, associated with tears of the posterior cruciate ligament (PCL), medial collateral ligament (MCL), medial meniscus, and probably the anterior cruciate ligament (ACL). Unlike Segond fracture, it is a very rare injury of the knee. CASE REPORT: Case one is a 24-year-old male with left tibial plateau and reverse Segond fracture with an magnetic resonance imaging (MRI) showing MCL avulsion, medial meniscus entrapped in fracture site and ACL tear but intact PCL. The second case is a 56-year-old female showing reverse Segond and lateral tibial plateau fracture confirmed by X-ray and computed tomography scan. MRI revealed intact PCL, detached medial meniscus from peripheral capsule and ACL injury. CONCLUSION: Based on this study and previous rare reports, reverse Segond fracture may not be accompanied by PCL injuries in all cases.

Traumatic knee injury patterns in Anatolian folk dancers: a case series and literature review.

Lower extremities, especially the knee region, are susceptible to traumatic injuries because of long-lasting hard landings and impacts. Most of the injuries described in the literature are associated with ballet. In this review study, the authors tried to present the traumatic knee injury patterns of the Anatolian folk dance. The Fire of Anatolia dance group consists of 82 dancers (37 males [45.1%] and 45 females [54.9%]) with the mean age of 27.96 (SD = 5.05) years (range: 18-38 years). The major folk dances of the region are Zeybek, Halay, Horon, Teke, Roman, Karsilama, Bar and Lezginka ("the Caucasian"). The dancers suffered from 9 orthopedic injuries requiring surgical treatment (3 meniscus tears, 4 anterior cruciate ligament tears, 1 posterior cruciate ligament tear, 1 patellar dislocation) during a 10-year period. The authors investigated solely the traumatic injuries of these folk dance styles and aimed at revealing the traumatic knee injury patterns in this case series and literature review. On the one hand, the Anatolian folk dancers experienced meniscus tears following frequent squats and twists on single leg stances, typical of Horon and Zeybek. On the other hand, anterior cruciate tears happened after jumps and landings in the Caucasian (Lezginka jump) dance. A posterior cruciate ligament tear was also seen after the Caucasian dance landing. The split figure in the Karsilama dance ended up with patellar dislocation. Certain dance figures seem to be related to specific types of injuries. Int J Occup Med Environ Health. 2019;32(5):585-93.

Comparison of knee laxity and isokinetic muscle strength in patients with a posterior cruciate ligament injury.

[Purpose] The aim of this study was to compare knee laxity and isokinetic muscle strength in patients with an isolated posterior cruciate ligament injury. [Subjects and Methods] Twenty high school rugby players with a previous posterior cruciate ligament injury and abnormal findings higher than surgical grade I were included. Laxity with 132 N of pressure was measured using Kneelax 3 to assess the stability of the posterior cruciate ligament, and flexor and extensor torques were measured at 60°/sec, 180°/sec, and 240°/sec to measure the isokinetic muscle strength of the knee joint. The average and standard deviation values were extracted from all data to assess the measured data. [Results] Regarding the ipsilateral and contralateral laxity, the deviation value at the peak force and maximum manual drawer was statistically significant. The peak torque and peak torque per body weight in isokinetic measurements were significantly different only for knee extensor torque at 60°/sec, 180°/sec, and 240°/sec. [Conclusion] Return to normal activities post injury is important. Thus base data gathered by comparing patients' ipsilateral and contralateral sides will serve as essential criteria for structuring future rehabilitation programs to facilitate functional improvements.

External fixator for treatment of the sub-acute and chronic multi-ligament-injured knee.

PURPOSE: To assess whether the use of an articulated external fixator provides improvements in the mobility, stability and subjective function of patients undergoing ligament reconstruction. METHODS: Thirty-three patients with sub-acute and chronic knee dislocation were subjected to multi-ligament reconstruction surgery. These patients were randomly allocated to two groups for immobilization after reconstruction: group 0-control (18 patients), with rigid knee bracing, and group 1-articulated external fixator (15 patients). The stability of the reconstructed ligaments was assessed after at least 14 months (26.6-month average) postoperatively by physical examination. Deficit of extension and flexion was measured in relation to the unaffected contralateral knee, and the Lysholm knee scoring scale questionnaire was applied. RESULTS: There was no difference in the assessment of joint stability between the groups. In group 1, patients showed less flexion deficit (4.8° ± 5.4° vs. 18.2° ± 14.8°, p < 0.05), and the percentage of patients with a flexion deficit of 5° or less were higher compared with group 0 (64 vs. 18 %, p < 0.05). There was no difference between groups in relation to extension loss. Group 1 also presented better Lysholm scores, with 73 % of patients rated as excellent or good compared with 35 % in group 0 (p < 0.05). CONCLUSIONS: Compared with the control rehabilitation protocol with rigid knee bracing in extension, the use of an articulated external fixator in the treatment of chronic multi-ligament-injured knees provided the same ligament stability, better final range of motion and improved Lysholm score. Patients presenting with chronic multi-ligament instability should be considered for articulated external fixation to supplement reconstruction procedures. LEVEL OF EVIDENCE: Randomized controlled trial, Level I.

Posterior tibial translation resulting from the posterior drawer manoeuver in cadaveric knee specimens: a systematic review.

PURPOSE: The purpose of this systematic review of cadaver-based biomechanical studies is to accurately quantify how much posterior tibial translation occurs during posterior drawer testing in normal and PCL-deficient knees. METHODS: A search of the electronic databases, MEDLINE and EMBASE, was performed to identify relevant cadaveric studies that reported posterior tibial translation during posterior drawer testing. Studies were combined to determine overall increase in posterior tibial translation after PCL sectioning at 90° of flexion. Methodological quality of included studies was assessed by two reviewers using a novel clinometric tool. An intraclass correlation coefficient with 95 % confidence intervals (CIs) was used to determine agreement between reviewers on quality scores. RESULTS: Combined analysis of 244 cadaveric specimens from 23 studies in which the PCL was sectioned yielded a mean net increase in tibial translation of 10.7 mm (95 % CI 9.68-11.8) with posterior drawer testing. Posterior tibial translation among cadaveric specimens with no disruption to any ligamentous structures was found to be 5.4 mm (95 % CI 4.3-6.6). CONCLUSIONS: Cadaveric data support previous study findings of >8 mm of posterior tibial translation on stress radiographs being indicative of isolated PCL insufficiency. Use of fixed reference points and strict control of tibial rotation are imperative to ensure accurate results in cadaveric studies and in the clinical setting when performing the posterior drawer examination. LEVEL OF EVIDENCE: III.

Quantification of functional brace forces for posterior cruciate ligament injuries on the knee joint: an in vivo investigation.

PURPOSE: Counteracting posterior translation of the tibia with an anterior force on the posterior proximal tibia has been demonstrated clinically to improve posterior knee laxity following posterior cruciate ligament (PCL) injury. This study quantified forces applied to the posterior proximal tibia by two knee braces designed for treatment of PCL injuries. METHODS: The forces applied by two knee braces to the posterior proximal tibia and in vivo three-dimensional knee kinematics of six adult, male, healthy volunteer subjects (mean ± standard deviation: height, 182.5 ± 5.2 cm; body mass, 83.2 ± 9.3 kg; body mass index, 24.9 ± 1.5 kg/m(2); age, 25.8 ± 2.9 years) were measured using a custom pressure mapping technique and traditional surface marker motion capture techniques, while subjects performed three functional activities. The activities included seated unloaded knee flexion, squatting, and stair descent in a new generation dynamic force (DF) PCL brace and a static force (SF) PCL brace. RESULTS: During unloaded flexion at the lowest force level setting, the force applied by the DF brace increased as a function of flexion angle (slope = 0.7 N/°; p < 0.001) compared to the SF brace effect. Force applied by the SF brace did not significantly change as a function of flexion angle (slope = 0.0 N/°; n.s.). By 45° of flexion, the average force applied by the DF brace (48.1 N) was significantly larger (p < 0.001) than the average force applied by the SF brace (25.0 N). The difference in force continued to increase as flexion angle increased. During stair descent, average force (mean ± standard deviation) at toe off was significantly higher (p = 0.013) for the DF brace (78.7 ± 21.6 N) than the SF brace (37.3 ± 7.2 N). Similar trends were observed for squatting and for the higher force level settings. CONCLUSIONS: The DF brace applied forces to the posterior proximal tibia that dynamically increased with increased flexion angle. Additionally, the DF brace applied significantly larger forces at higher flexion angles compared to the SF brace where the PCL is known to experience larger in situ forces. Clinical studies are necessary to determine whether the loading characteristics of the DF brace, which more closely replicated the in situ loading profile of the native PCL, results in long-term improved posterior knee laxity following PCL injury. LEVEL OF EVIDENCE: II.

Posterior tibial displacement in the PCL-deficient knee is reduced compared to the normal knee during gait.

PURPOSE: Most individuals with an isolated posterior cruciate ligament (PCL) injury do not complain of disability even if posterior instability is objectively revealed by a static physical examination, such as the posterior drawer test. This suggests it is insufficient to only evaluate posterior instability under static conditions. Therefore, we have investigated the effect of isolated PCL injury on the detailed kinematics of the knee in a dynamic environment such as during gait. METHODS: Eight unilateral PCL-deficient males and eight healthy control volunteers participated in this study. Isolated PCL injury was diagnosed by clinical examination. Stress X-ray imaging showed an average side-to-side difference of 12.7 ± 3.5 mm. Knee kinematics including anteroposterior tibial displacement were analysed during walking using the point cluster technique. RESULTS: Posterior tibial displacement from initial contact was significantly smaller during 9-22 % of the gait cycle by an average of 0.4 cm in the PCL group, compared to controls. In the PCL-deficient knee, the external rotational angle increased by an average of 3.3° at the loading response during 3-11 % of the gait cycle and the varus angle from initial contact increased by an average of 2.0° during 28-52 % of the gait cycle, compared to controls. CONCLUSIONS: Dynamic changes in the rotation and posterior translation patterns were seen after isolated PCL injury, suggesting the kinematics of PCL-deficient knees might be different to normal knees. These factors may contribute to long-term osteoarthritic change. Consequently, when choosing conservative treatment for PCL injury, these changes should be considered to prevent osteoarthritic change. LEVEL OF EVIDENCE: III.