Unicompartmental knee arthroplasty combined with posterior cruciate ligament reconstruction: a case report.

BACKGROUND: In this study, we present the unique case of a patient with knee osteoarthritis (OA) of the medial compartment and posterior cruciate ligament (PCL) deficiency who underwent simultaneous medial unicompartmental knee arthroplasty (UKA) and PCL reconstruction. CASE PRESENTATION: A 49-year-old male patient presented with a 1-year history of pain and instability in the left knee. The patient had previously experienced a trauma-related injury to the PCL of the left knee that was left untreated. Imaging and physical examination confirmed the presence of left medial knee OA along with PCL rupture. To address these issues, the patient underwent UKA combined with PCL reconstruction. The patient's Lysholm score was 47 before surgery and 81 three months after surgery, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score was 29 before surgery and 18 three months after surgery, and the International Knee Documentation Committee (IKDC) subjective score was 56.3 before surgery and 74.7 three months after surgery. Six months after surgery, the patient's gait returned to normal, and he was able to jog. CONCLUSION: This case report presents the first instance of UKA combined with PCL reconstruction and introduces a novel treatment approach for patients suffering from medial knee OA and ligament injury.

Clinical efficacy and kinematic analysis of Chinese knotting technique-assisted posterior cruciate ligament reconstruction: A retrospective analysis.

To investigate the clinical efficacy and knee joint kinematic changes of posterior cruciate ligament (PCL) reconstruction assisted by Chinese knotting technique (CKT). A retrospective analysis was conducted on 88 cases of PCL reconstructive surgery admitted between September 2016 and September 2020. All patients were operated on by the same senior doctor and his team. The patients were divided into 2 groups according to whether the CKT was applied, with 44 cases in each group. Both groups received active rehabilitation treatment after surgery. All patients were followed up for more than 2 years. International knee documentation committee, hospital for special surgery (HSS), and Lysholm scores were used to evaluate the clinical efficacy of the 2 methods at 3, 12, and 24 months after surgery. The motion cycle and kinematic indices of the knee joint were measured by the Opti_Knee three-dimensional motion measurement system before surgery and at 3, 12, and 24 months after surgery. A secondary arthroscopic examination was performed at 12 months after surgery, MAS score was used to evaluate the secondary endoscopic examination of PCL. All the patients had wound healing in stage I without infection. International Knee in both sets Documentation Committee scores, HSS scores and Lysholm scores were gradually improved at all time points (P < .05); compared with the traditional group, the HSS score was higher in the reduction group 12 months after surgery (P < .05), but there was no significant difference at 24 months after surgery. 12 months and 24 months after 3 dimensional motion measurement system using Opti_Knee showed a reduction group before and after displacement and displacement of upper and lower range than the traditional group (P < 0. 05). One year after surgery, the good and good rate of MAS score reduction group was higher than traditional group. CKT assisted PCL reconstruction can improve the subjective function score of the affected knee joint and the results of secondary microscopy. Satisfactory knee kinematic function can be obtained in the early stage, and the anteroposteric relaxation of the knee joint can be reduced.

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

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

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

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

Posterior Cruciate Ligament Reconstruction Current Concepts Review.

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

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

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

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

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

A modified anatomical posterior cruciate ligament reconstruction technique using the posterior septum and posterior capsule as landmarks to position the low tibial tunnel.

BACKGROUND: Lowering the exit position of the tibial tunnel can improve the clinical efficacy of posterior cruciate ligament (PCL) reconstruction, however, there is no unified positioning standard. This study aimed to use novel soft tissue landmarks to create a low tunnel. METHODS: A total of 14 human cadaveric knees and 12 patients with PCL injury were included in this study. Firstly, we observed the anatomical position between the PCL, posterior septum, and other tissue, and evaluated the relationship between the center of the low tibial tunnel (SP tunnel) and posterior septum and distal reflection of posterior capsule, and using computed tomography (CT) to evaluate distance between the center of the SP tunnel with bony landmarks. Then, evaluated the blood vessels content in the posterior septum with HE staining. Finally, observed the posterior septum and distal reflection of the posterior capsule under arthroscopy to explore the clinical feasibility of creating a low tibial tunnel, and assessed the risk of surgery by using ultrasound to detect the distance between the popliteal artery and the posterior edge of tibial plateau bone cortex. RESULTS: In all 14 cadaveric specimens, the PCL tibial insertions were located completely within the posterior medial compartment of the knee. The distance between the center of the SP tunnel and the the articular surface of tibial plateau was 9.4 ± 0.4 mm. All SP tunnels retained an intact posterior wall, which was 1.6 ± 0.3 mm from the distal reflection of the posterior capsule. The distances between the center of the SP tunnel and the the articular surface of tibial plateau, the champagne glass drop-off were 9.2 ± 0.4 mm (ICC: 0.932, 95%CI 0.806-0.978) and 1.5 ± 0.2 mm (ICC:0.925, 95%CI 0.788-0.975) in CT image. Compared with the posterior capsule, the posterior septum contained more vascular structures. Last, all 12 patients successfully established low tibial tunnels under arthroscopy, and the distance between the posterior edge of tibial plateau bone cortex and the popliteal artery was 7.8 ± 0.3, 9.4 ± 0.4 and 7.4 ± 0.3 mm at 30°, 60° and 90° flexion angels after filling with water and supporting with shaver in posterior-medial compartment of knee joint. CONCLUSIONS: A modified low tibial tunnel could be established in the PCL anatomical footprint by using the posterior septum and posterior capsule as landmarks.

Outcomes after Anatomic Double-Bundle Posterior Cruciate Ligament Reconstructions Using Transtibial and Tibial Inlay Techniques.

Surgical reconstruction is recommended for symptomatic posterior cruciate ligament (PCL) deficiency. While anatomic double-bundle PCL reconstruction (PCLR) has been reported to be associated with biomechanical and clinical advantages over other methods, there is still debate regarding the optimal technique for tibial positioning and fixation. Based on reported advantages and disadvantages, we employed two tibial fixation techniques, transtibial (TT) and tibial inlay (TI) for anatomic double-bundle PCLR with technique selection based on body mass index, comorbidities, and primary versus revision surgery. This study aimed to compare clinical outcomes following PCLR utilizing either TT or TI techniques to validate relative advantages, disadvantages, and indications for each based on the review of prospectively collected registry data. For 37 patients meeting inclusion criteria, 26 underwent arthroscopic TT PCLR using all-soft- tissue allograft with suspensory fixation in the tibia and 11 patients underwent open TI PCLR using an allograft with calcaneal bone block and screw fixation in the tibia. There were no significant preoperative differences between cohorts. Success rates were 96% for TT and 91% for TI with all successful cases documented to be associated with good-to-excellent posterior stability and range of motion in the knee at the final follow-up. In addition, patient-reported outcome scores were within clinically meaningful ranges for pain, function, and mental health after PCLR in both cohorts, suggesting similarly favorable functional, social, and psychological outcomes. Patient-reported pain scores at 6 months postoperatively were significantly (p = 0.042) lower in the TT cohort, which was the only statistically significant difference in outcomes noted. The results of this study support the use of TT and TI techniques for double-bundle anatomic PCLR in restoring knee stability and patient function when used for the treatment of isolated and multiligamentous PCL injuries. The choice between tibial fixation methods for PCLR can be appropriately based on patient and injury characteristics that optimize respective advantages for each technique.

The Effect of Aging on Outcomes after Posterior Cruciate Ligament Reconstruction: Older (≥ 50 Years) Versus Younger (< 50 Years) Patients.

Background: This study aimed to evaluate the clinical and radiological outcomes after posterior cruciate ligament (PCL) reconstruction in ≥ 50-year-old patients. Methods: This retrospective case-control study reviewed 28 patients (age, ≥ 50 years) who underwent PCL reconstruction from 2004 to 2018. These patients were 1 : 1 matched to < 50-year-old patients by sex. Clinical, radiological, and survivorship outcomes of the patients were assessed at the final follow-up. Failure of PCL reconstruction was defined as the requirement for additional surgery (revision PCL reconstruction, high tibial osteotomy, or arthroplasty) due to unrelieved symptoms or grade III instability on stress radiographs. Results: The mean follow-up periods (± standard deviation) in < 50- and ≥ 50-year-old patients were 3.9 ± 1.0 years and 3.6 ± 1.9 years, respectively (p = 0.583). In < 50- and ≥ 50-year-old patients, the mean International Knee Documentation Committee scores were 64.1 ± 10.3 and 53.5 ± 17.3; mean Lysholm scores were 81.4 ± 13.0 and 66.3 ± 21.5; and mean Tegner activity scores were 6.1 ± 1.4 and 4.8 ± 1.7, respectively (p = 0.032, p = 0.018, and p = 0.016, respectively). Side-to-side differences in posterior translation on Telos stress radiographs at the final follow-up were 4.4 ± 1.4 mm and 6.9 ± 3.0 mm in < 50- and ≥ 50-year-old patients, respectively (p < 0.001). According to Kaplan-Meier analysis, the failure-free survival rates of both groups were significantly different in the follow-up period (p = 0.014). The failure-free survival rates for < 50- and ≥ 50-year-old patients were 100% and 78.6%, respectively. Conclusions: Clinical, radiological, and survivorship outcomes were inferior among ≥ 50-year-old patients after PCL reconstruction. Thus, surgeons should be careful when deciding and performing PCL reconstruction in patients 50 years old or over.

Posterior Cruciate Ligament Agenesis Requiring Surgical Reconstruction.

Agenesis of the posterior cruciate ligament (PCL) is a rare disorder often found in conjunction with various other abnormalities within the knee. A 15-year-old adolescent boy presented with an absent PCL, leading to intermittent symptoms. At the age of 20 years, the patient underwent arthroscopically assisted PCL reconstruction. The patient was permitted to weightbear immediately after the procedure and started physical therapy 4 weeks after the procedure. No complications were encountered at the 2-year follow-up.

Differences in postoperative knee joint function and prognostic quality of life in patients undergoing posterior cruciate ligament reconstruction at different surgical timing under enhanced recovery after surgery.

To explore the differences in postoperative knee joint function and prognostic quality of life in patients undergoing posterior cruciate ligament (PCL) reconstruction at different timing of surgery under the enhanced recovery after surgery (ERAS) protocol. A total of 266 cases of PCL injury admitted to our hospital between March 2019 and October 2022 were included in this retrospective study and divided them into a short-term group (147 cases with PCL reconstruction completed within 3 weeks after injury) and a long-term group (119 cases with PCL reconstruction performed 3 weeks after injury) according to the timing of surgery after injury. All patients received ERAS care during treatment. The operation time, intraoperative blood loss, and incision length of both cohorts were counted to evaluate the clinical efficacy. Perioperative patients were assessed by the Visual Analogue Scale for pain severity. The pre- and post-operative knee function and knee joint range of motion were assessed by the International Knee Documentation Committee and Lysholm Knee Scoring Scale. Furthermore, the complication rate was counted and the quality of life was evaluated by the Short-Form 36 Item Health Survey. Patients were also assessed for their psychological states using the Self-rating Anxiety/Depression Scale and their satisfaction with care. The 2 groups showed similar operation time, intraoperative blood loss, incision length, overall response rate, and Visual Analogue Scale (P > .05), but the short-term group had higher knee range of motion and scores of International Knee Documentation Committee and Lysholm Scale than the long-term group (P < .05). A similar complication rate was also determined in the 2 groups (P > .05), but the Short-Form 36 Item Health Survey scores were significantly higher in the short-term group (P < .05). Self-rating Anxiety Scale and Self-rating Depression Scale in both groups decreased after treatment (P < .05), and no statistical difference was determined in nursing satisfaction (P = 198). PCL reconstruction within 3 weeks after PCL injury is more conducive to the recovery of patients' knee joint function, and the ERAS protocol can more effectively improve the therapeutic effect of patients.

Safe femoral tunnel drilling angles avoid injury to the medial and posteromedial femoral anatomic structures during single-bundle posterior cruciate ligament reconstruction with the inside-out technique.

PURPOSE: To investigate the relationship between the medial and posteromedial femoral anatomic structures and the femoral tunnel exit produced by different tunnel orientations when creating the femoral tunnel for posterior cruciate ligament reconstruction (PCLR) using the inside-out (IO) technique and to estimate safe tunnel orientations to minimize the risk of iatrogenic injury to these structures. METHODS: Eleven cadaveric knees were used. The medial and posteromedial aspects of each knee joint were dissected to reveal the "safe zone," which is a bony area that avoids the distribution or attachment of at-risk structures (MCL, PMC structures, and articular cartilage), while remaining 10 mm away from the articular cartilage. The hypothesis of this study was that by creating the femoral tunnel at specific angles using the IO technique, the tunnel outlet would be as close to the safe zone as possible, protecting the at-risk structures from damage. Femoral tunnels were drilled at 20 different angle combinations on each specimen: 0°, 15°, 30°, 45°, and 60° relative to a line parallel to the transepicondylar axis in the axial plane, as well as 15°, 30°, 45°, and 60° relative to a line parallel to the femoral axis in the coronal plane. The positional relationship between each tunnel exit and the safe zone was recorded, and the shortest distance between the exit center and the safe zone boundary was measured. RESULTS: The risk of iatrogenic injury differed depending on the drilling orientation (χ2 = 168.880, P < 0.001). Femoral drilling angle combinations of 45/45°, 45/60°, 60/30°, 60/45°, and 60/60° (axial/coronal) were considered relatively safer than other orientations (P < 0.05). The shortest distance between the tunnel exit and the safe zone boundary was negatively correlated with the angle in the axial plane (P < 0.001, r = - 0.810). CONCLUSIONS: When creating the IO femoral tunnel for single-bundle PCL reconstruction, angle combinations of 45/45°, 45/60°, 60/30°, 60/45°, and 60/60° (axial/oblique coronal) could be utilized to prevent at-risk structures from being damaged. The drilling angles and the safe zone can be employed to optimize the femoral tunnel in PCLR.

Effect of Posterior Tibial Slopes on Graft Survival Rates at 10 Years After Primary Single-Bundle Posterior Cruciate Ligament Reconstruction.

BACKGROUND: Recent biomechanical studies have reported that stress on the posterior cruciate ligament (PCL) graft increases as the posterior tibial slope (PTS) decreases (flattened) in knees with single-bundle (SB) and double-bundle PCL reconstruction. Clinical studies of SB PCL reconstruction have shown that a flattened PTS is associated with a lesser reduction in posterior tibial translation. There is no long-term study on the clinical outcomes and graft survival rates of SB PCL reconstruction based on the medial and lateral PTSs measured on magnetic resonance imaging. HYPOTHESIS: Flattened medial and lateral PTSs are associated with poor clinical outcomes and graft survival rates at a minimum 10-year follow-up after SB PCL reconstruction. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: In this cohort study, we retrospectively reviewed 46 patients (mean age, 28.8 ± 9.9 years) who underwent primary SB PCL reconstruction between 2000 and 2009. They were followed up for a minimum of 10 years. The medial and lateral PTSs were measured on preoperative magnetic resonance imaging. As a previous study reported that a steeper medial or lateral PTS showed a higher risk of anterior tibial translation at thresholds of 5.6° and 3.8°, respectively, the patients were divided into 2 groups based on the cutoff values of both the medial (≤5.6° vs >5.6°) and lateral (≤3.8° vs >3.8°) PTSs. Clinical scores (International Knee Documentation Committee subjective score, Lysholm score, and Tegner activity score), radiological outcomes (side-to-side difference [SSD] on stress radiography and osteoarthritis progression), and graft survival rates were compared between the groups at the last follow-up. RESULTS: All clinical scores and the progression of osteoarthritis demonstrated no significant difference between the 2 subgroups of both the medial and lateral PTS groups. The mean SSD on stress radiography after SB PCL reconstruction was significantly greater in patients with a medial PTS ≤5.6° than in patients with a medial PTS >5.6° (8.4 ± 3.9 vs 5.1 ± 2.9 mm, respectively; P = .030), while the lateral PTS subgroups after SB PCL reconstruction demonstrated no significant difference. The minimum 10-year graft survival rate was significantly lower in patients with a medial PTS ≤5.6° (68.4% vs 92.6%, respectively; P = .029) and a lateral PTS ≤3.8° (50.0% vs 91.7%, respectively; P = .001). CONCLUSION: A flattened medial PTS (≤5.6°) was associated with an increased SSD on stress radiography, and both flattened medial (≤5.6°) and lateral (≤3.8°) PTSs resulted in lower graft survival rates at a minimum 10-year follow-up after primary SB PCL reconstruction.

Different femoral tunnel placement in posterior cruciate ligament reconstruction: a finite element analysis.

BACKGROUND: At present, there is no consensus on the optimal biomechanical method for Posterior cruciate ligament (PCL) reconstruction, and the "critical corner" that is produced by the femoral tunnel is currently considered to be one of the main reasons for PCL failure. Thus, the purpose of this study was to identify one or several different tunnels of the femur, thereby reducing the influence of the "critical corner" without reducing the posterior stability of the knee. METHODS: CT and MRI data of the knee joint of a healthy adult man were collected, and computer-related software was used to reconstruct the finite element model of the knee joint, to provide different properties to different materials and to allow for the performance of a finite element analysis of the reconstructed model. The position of the femoral tunnel was positioned and partitioned according to anatomical posture, and three areas were divided (the antero-proximal region, the antero-distal region and the posterior region). In addition, we applied a posterior tibial load of 134 N to the reconstructed model, recorded and compared different tunnels of the femur, conducted peak stress at the flexion of the knee joint of 0°, 30°, 60° and 90°, and elicited the displacement of the proximal tibia. RESULTS: Among the 20 different femoral tunnels, the graft peak stress was lower in tunnels 4, 12 and 18 than in the PCL anatomical footpath tunnel 13, especially at high flexion angles (60° and 90°). These three tunnels did not increase the posterior displacement of the proximal tibia compared with the anatomical footpath tunnel 13. CONCLUSION: In summary, among the options for PCL reconstruction of the femoral tunnel, the tunnels located 5 mm distal to the footprint and 5 mm anterior to the footprint could reduce the peak stress of the graft; additionally, it may reduce the "critical corner" and was shown to not reduce the posterior stability of the knee joint.

Biomechanical Comparison of Anatomic Versus Lower of Anteromedial and Anterolateral Tibial Tunnels in Posterior Cruciate Ligament Reconstruction.

OBJECTIVE: In order to reduce the "killer turn" effect, various tibial tunnels have been developed. However, few studies investigated the biomechanical effects of different tibial tunnels during PCL reconstruction. This study aims to compare the time-zero biomechanical properties of anteromedial, anterolateral, lower anteromedial, and lower anterolateral tibial tunnels in transtibial posterior cruciate ligament (PCL) reconstruction under load-to-failure loading. METHODS: Porcine tibias and bovine extensor tendons were used to simulate in vitro transtibial PCL reconstruction. Forty bovine extensor tendons and 40 porcine tibias were randomly divided into four experimental groups: anteromedial tunnel group (AM group, n = 10), anterolateral tunnel group (AL group, n = 10), lower anteromedial tunnel group (L-AM group, n = 10), and lower anterolateral tunnel group (L-AL group, n = 10). The biomechanical test was then carried out in each group using the load-to-failure test. The ultimate load (in newtons), yield load (in newtons), tensile stiffness (in newtons per millimeter), load-elongation curve, failure mode, and tibial tunnel length (in millimeter) were recorded for each specimen. One-way analysis of variance (ANOVA) was used to compare the mean differences among the four groups. RESULTS: The biomechanical outcomes showed that there were no differences in the mean tensile stiffness and failure mode among four groups. The ultimate load and yield load of the L-AM group were significantly higher than those of other three groups (P < 0.05). For the AM group, its ultimate load is significantly higher than that of the L-AL group (P < 0.05), and its yield load is higher than that of the AL group and L-AL group (P < 0.05). However, we found no significant differences in either ultimate load or yield load between AL group and L-AL group (P > 0.05). There was significant statistical difference in the length of tibial tunnel between anatomic groups (AM and AL) and lower groups (L-AM and L-AL) (P < 0.05). CONCLUSION: Compared with the anteromedial, anterolateral, and lower anterolateral tibial tunnel, the lower anteromedial tibial tunnel showed better time-zero biomechanical properties including ultimate load and yield load in transtibial PCL reconstruction.

Posterior cruciate ligament reconstruction using PCL inlay technique with the patient supine in bicruciate ligament injury reconstruction.

BACKGROUND: Surgical reconstruction of the posterior cruciate ligament (PCL) can be technically challenging given the proximity of the popliteal artery to the PCL tibial insertion. This "no-safe zone" makes some knee surgeons less confident and willing to perform this surgical procedure. SURGICAL TECHNIQUE: We present a PCL tibial inlay reconstruction technique using a set of instruments involving three tools (a slot cut, a bone plug positioner, and an impactor). CONCLUSION: This set of instruments allows a more reproducible posteromedial approach and to produce a PCL tibial slot in a posterior cruciate ligament inlay reconstruction with the patient supine in bicruciate ligament injury reconstruction.

A Comprehensive Meta-analysis of Clinical and Biomechanical Outcomes Comparing Double-Bundle and Single-Bundle Posterior Cruciate Ligament Reconstruction Techniques.

BACKGROUND: Posterior cruciate ligament (PCL) reconstruction techniques have historically focused on single-bundle (SB) reconstruction of the larger anterolateral bundle without addressing the codominant posteromedial bundle. The SB technique has been associated with residual laxity and instability, leading to the development of double-bundle (DB) reconstruction techniques. PURPOSE: To perform a meta-analysis of comparative clinical and biomechanical studies to differentiate the pooled outcomes of SB and DB PCL reconstruction cohorts. STUDY DESIGN: Meta-analysis and systematic review: Level of evidence, 3. METHODS: Six databases were queried in February 2022 for literature directly comparing clinical and biomechanical outcomes for patients or cadaveric specimens undergoing DB PCL reconstruction against SB PCL reconstruction. Biomechanical outcomes included posterior tibial translational laxity, external rotational laxity, and varus laxity at 30° and 90° of knee flexion. Clinical outcomes included the side-to-side difference in posterior tibial translation during postoperative stress radiographs, risk of a major complication, and the following postoperative patient-reported outcome measures: Lysholm, Tegner, and International Knee Documentation Committee (IKDC) subjective and objective scores. A random-effects model was used to compare pooled clinical and biomechanical outcomes between the cohorts. RESULTS: Fifteen biomechanical studies and 13 clinical studies were included in this meta-analysis. The DB group demonstrated significantly less posterior tibial translation at 30° and 90° of knee flexion (P < .00001). Additionally, the DB group demonstrated significantly less external rotation laxity at 90° of knee flexion (P = .0002) but not at 30° of knee flexion (P = .33). There was no difference in varus laxity between the groups at 30° (P = .56) or 90° (P = .24) of knee flexion. There was significantly less translation on stress radiographs in the DB group (P = .02). Clinically, there was no significant difference between the groups for the Lysholm score (P = .95), Tegner score (P = .14), or risk of a major complication (P = .93). DB PCL reconstruction led to significantly higher odds of achieving "normal" or "near normal" objective IKDC outcomes for the included prospective studies (P = .04) and higher subjective IKDC scores (P = .01). CONCLUSION: DB PCL reconstruction leads to superior biomechanical outcomes and clinical outcomes relative to SB PCL reconstruction. Re-creating native anatomy during PCL reconstruction maximizes biomechanical stability and clinical outcomes.

Biomechanical comparison of proximal, distal, and anatomic tibial tunnel for transtibial posterior cruciate ligament reconstruction.

No consensus has been reached on the optimal position of PCL tibial tunnel. The purpose of this study was to compare the biomechanical properties of proximal, distal and anatomic tibial tunnel in transtibial posterior cruciate ligament reconstruction. An in-vitro model of transtibial posterior cruciate ligament reconstruction was simulated using porcine tibias and bovine extensor tendons. Two models of biomechanical testing, load-to-failure loading, and cyclic loading, were performed in this study. The load-to-failure loading found that distal tibial tunnel resulted in greater ultimate load and yield load than the anatomic and proximal tunnel group (p < 0.05), whereas there were no significant differences in mean tensile stiffness among three groups (p > 0.05). The cyclic loading found no differences in the graft displacement at 250, 500, and 1000 cycles among three groups (p > 0.05). It was found that distal tibial tunnel showed superior ultimate load and yield load in load-to-failure loading testing compared with proximal and anatomic tibial tunnels, whereas no significant difference was found in terms of the mean displacement of the survived grafts in cyclic loading testing among three groups.