Screw placement through a higher medial portal provides better initial stability in arthroscopic ACL tibial avulsion fracture fixation: a finite element analysis.

OBJECTIVE: The objective of this study was to investigate the initial stability of different screw placements in arthroscopic anterior cruciate ligament (ACL) tibial avulsion fracture fixation. METHODS: A three-dimensional knee model at 90° flexion was utilized to simulate type III ACL tibial avulsion fracture and arthroscopic screw fixation through different portals, namely the central transpatellar tendon portal (CTP), anterolateral portal (ALP), anteromedial portal (AMP), lateral parapatellar portal (LPP), medial parapatellar portal (MPP), lateral suprapatellar portal (LSP), medial suprapatellar portal (MSP). A shear force of 450 N was applied to the finite element models at 30° flexion to simulate the failure condition. The displacement of the bony fragment and the volume of the bone above 25,000 µ-strain (damaged bone volume) were calculated around the screw path. RESULTS: When the screw was implanted through CTP, the displacement of the bony fragment reached the maximum displacement which was 1.10 mm and the maximum damaged bone volume around the screw path was 148.70 mm3. On the other hand, the minimum displacement of the bony fragment was 0.45 mm when the screw was implanted through LSP and MSP. The minimum damaged bone volume was 14.54 mm3 around the screw path when the screw was implanted through MSP. CONCLUSION: Screws implanted through a higher medial portal generated less displacement of the bony fragment and a minimum detrimental strain around the screw path. The findings are clinically relevant as they provide biomechanical evidence on optimizing screw placement in arthroscopic ACL tibial avulsion fracture fixation.

Comparison of the quadrant method measuring four points and bernard method in femoral tunnel position evaluation on 3-dimensional reconstructed computed tomography after anatomical single-bundle anterior cruciate ligament reconstruction.

PURPOSE: This prospective study aimed to compare the postoperative evaluation of the quadrant method measuring four points and Bernard method in femoral tunnel position evaluation on 3-Dimensional (3D) reconstructed computed tomography (CT) following the arthroscopic single-bundle anterior cruciate ligament (ACL) reconstruction. METHODS: Thirty-eight patients with ACL tears that were reconstructed using single-bundle ACL reconstruction between May 2021 and March 2023 were included in this study. Postoperative 3D CT images were obtained after the operation. The femoral tunnel position was measured by use of the quadrant method measuring four points and Bernard method. RESULTS: Average mean position of the femoral tunnel insertion center on the 3D CT image was at 26.16 ± 6.27% in the x-coordinate and at 24.36 ± 5.52% in the y-coordinate according to the Bernard method. Meanwhile, the position of the femoral insertion of the ACL measured by the quadrant method measuring four points was 24.2% ± 6.86% in the x-coordinate and 21.16% ± 5.14% in the y-coordinate. CONCLUSIONS: Both the quadrant method measuring four points and Bernard method were effective in femoral tunnel position evaluation on 3D reconstructed CT. Application of the quadrant method measuring four points on 3D CT showed the advantage that measurement can be taken regardless of the shape of the bone tunnel.

Meta-analysis of the value of dual-energy computed tomography in the diagnosis of anterior cruciate ligament injuries of the knee.

BACKGROUND: This meta-analysis assessed the efficacy of dual-energy computed tomography (DECT) in the diagnosis of anterior cruciate ligament (ACL) injuries. METHODS: The literature search was performed up to December 8, 2023, and included a comprehensive examination of several databases: PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), Wanfang, and VIP. Diagnostic metrics sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and a summary receiver operating characteristic (SROC) were determined using a bivariate model analysis. Heterogeneity within the data was explored through subgroup analyses, which considered variables including geographical region, use of magnetic resonance imaging (MRI), arthroscopy, and study design. RESULTS: The analysis included ten studies encompassing 544 patients. DECT demonstrated substantial diagnostic utility for ACL injuries of the knee, with a sensitivity of 0.91 (95% confidence interval [CI]: 0.88-0.94), a specificity of 0.90 (95% CI: 0.81-0.95), a PLR of 9.20 (95% CI: 4.50-19.00), a NLR of 0.10 (95% CI: 0.06-0.14), a DOR of 97.00 (95% CI: 35.00-268.00), and an area under the curve (AUC) of 0.95 (95% CI: 0.93-0.97). The subgroup analyses consistently showed high diagnostic precision for ACL injuries across Asian population (sensitivity: 0.91, specificity: 0.91, PLR: 9.90, NLR: 0.09, DOR: 105.00, AUC: 0.96), in MRI subgroup (sensitivity: 0.85, specificity: 0.94, PLR: 9.57, NLR: 0.18, DOR: 56.00, AUC: 0.93), in arthroscopy subgroup (sensitivity: 0.92, specificity: 0.89, PLR: 8.40, NLR: 0.09, DOR: 94.00, AUC: 0.95), for prospective studies (sensitivity: 0.92, specificity: 0.88, PLR: 7.40, NLR: 0.09, DOR: 78.00, AUC: 0.95), and for retrospective studies (sensitivity: 0.91, specificity: 0.93, AUC: 0.93). CONCLUSION: DECT exhibits a high value in diagnosing ACL injuries. The significant diagnostic value of DECT provides clinicians with a powerful tool that enhances the accuracy and efficiency of diagnosis and optimizes patient management and treatment outcomes.

The modified suture-bridge technique for treating avulsion fracture of minors tibial eminence of anterior cruciate ligament: a retrospective study.

PURPOSE: This study aimed to evaluate the clinical and radiological outcomes of modified suture-bridge technique fixation for anterior cruciate ligament (ACL) tibial avulsion fracture. METHOD: Minors who underwent arthroscopic reduction and modified suture bridge fixation of ACL tibial avulsion fracture between January 2018 and January 2022 were retrospectively analyzed. Postoperative MRI and X-ray examinations were performed to evaluate the presence of epiphyseal plate injury and fracture healing. Moreover, KT-1000 side-to-side difference, Lachman test, range of motion (ROM), the subjective Knee score of the International Knee Documentation Committee (IKDC), Lysholm Knee score, and Tegner activity grade score were evaluated preoperatively and at the minimum 1-year follow-up visit. RESULTS: A total of 16 participants met the inclusion criteria. They had a mean age of 12.6 years (range, 9-16 years); mean time to surgery, 6.9 days (range, 2-13 days) and had a minimum of 12 months clinical follow-up (mean, 25.4 months; range, 12-36 months) after surgery. Postoperative radiographs and MRI showed no injury to the epiphyseal plate, optimal reduction immediately after the operation, and bone union within three months in all patients. All of the following showed significant improvements (pre- vs. postoperatively): mean KT-1000 side-to-side difference (8.6 vs. 1.5; p < 0.05), Lachman tests (2 grade 9 and 3 grade 7 vs. 0 grade 12 and 1 grade 4; p < 0.05), IKDC subjective score (48.3 vs. 95.0; p < 0.05), mean Lysholm score (53.9 vs. 92.2; p < 0.05), mean Tegner activity score (3.2 vs. 8.3; p < 0.05) and mean ROM (42.9°vs 133.1°; p < 0.05). CONCLUSION: Arthroscopic reduction and modified suture bridge fixation for ACL tibial avulsion fracture is a dependable and recommended treatment that can effectively restore the stability and function of the knee and is worthy of clinical promotion.

The Anterior Notch Area for 3 Types of Notch Geometry, an Individualized Approach for Choosing the ACL Graft Size.

Background: The intercondylar notch (ICN) is an important element of knee morphometry, in close relation to the anterior cruciate ligament (ACL). To find the average are of the anterior notch in each ICN specific shape (A-, W-, or U-shape). Methods: Magnetic resonance imaging (MRI) scans were independently analyzed by two experts, one orthopedic surgeon and one imaging physician. In all cases, the following measurements were done according to the existing definitions: ICN type, aICN area. Results: 65 cases (A-35.4%, W-26.2%, U-38,5%) were included in study; A and W notch types have smaller aICN areas, while U-type notch has bigger aICN area. Conclusion: The anterior intercondylar notch area varies significantly for each specific shape (A-, W, or U-shape), and does not corelates with height. This needs to be considered during ACL reconstruction, when choosing graft size.

Comparison of femoral tunnel position and knee function in anterior cruciate ligament reconstruction: a retrospective cohort study using measuring-fluoroscopy method versus bony marker method.

BACKGROUND: Previous studies have shown that surgical technique errors especially the wrong bone tunnel position are the primary reason for the failure of anterior cruciate ligament (ACL) reconstruction. In this study, we aimed to compare the femoral tunnel position and impact on knee function during the ACL reconstruction using measuring combined with fluoroscopy method and bony marker method for femoral tunnel localization. METHODS: A retrospective cohort study of patients undergoing ACL reconstruction using the bony marker method or measuring combined with fluoroscopy for femoral tunnel localization was conducted between January 2015 and January 2020. A second arthroscopic exploration was performed more than 1 year after surgery. Data regarding patient demographics, the femoral tunnel position, results of the Lysholm score, the International Knee Documentation Committee (IKDC) score, KT-1000 side-to-side difference, pivot shift grade, and Lachman grade of the knee were collected. RESULTS: A total of 119 patients were included in the final cohort. Of these, 42 cases were in the traditional method group, and 77 cases were in the measuring method group. The good tunnel position rate was 26.2% in the traditional method group and 81.8% in the measuring method group (p < 0.001). At the final follow-up, the Lysholm and IKDC scores were significantly greater in the measuring method group than the traditional method group (IKDC: 84.9 ± 8.4 vs. 79.6 ± 6.4, p = 0.0005; Lysholm: 88.8 ± 6.4 vs. 81.6 ± 6.4, p < 0.001). Lachman and pivot shift grades were significantly greater in the measuring method group (p = 0.01, p = 0008). The results of KT-1000 side-to-side differences were significantly better in the measuring method group compared with those in the traditional method group (p < 0.001). CONCLUSIONS: The combination of the measuring method and intraoperative fluoroscopy resulted in a concentrated tunnel position on the femoral side, a high rate of functional success, improved knee stability, and a low risk of tunnel deviation. This approach is particularly suitable for surgeons new to ACL reconstructive surgery.

Do the Clinical and Radiological Features of Knees with Mucoid Degeneration of the Anterior Cruciate Ligament Differ According to Knee Osteoarthritis Status?

Background: The etiology and pathology of mucoid degeneration of the anterior cruciate ligament (MD-ACL) remain poorly understood. MD-ACL may be associated with knee osteoarthritis (OA) or a mechanism other than OA. This study evaluated the radiological differences between knees with MD-ACL and those with a normal ACL and compared the clinical and radiological features of knees with MD-ACL according to the knee OA status. Methods: This retrospective study compared the radiological features of the intercondylar notch width index (NWI) and posterior tibial slope (PTS) of 67 MD-ACL patients (MD group) and 67 age-, sex-, and OA grade-matched patients with a normal ACL (control group). During the subgroup analysis, MD-ACL patients were divided into the non-OA subgroup (n = 41) and OA subgroup (n = 26). The pain location and characteristics of the knee, PTS, and NWI were compared between these subgroups. Results: Compared to the control group, the MD group had a lower NWI (0.26 ± 0.03 vs. 0.28 ± 0.01, p < 0.001) and a larger PTS (11.3° ± 3.0° vs. 9.2° ± 2.5°, p < 0.001). During the subgroup analysis, the most common pain locations were the posterior and medial aspects of the knee in the non-OA subgroup (43.9%) and OA subgroup (53.8%), respectively. Pain on terminal flexion was the most common pain characteristic in both subgroups (non-OA subgroup, 73.1%; OA subgroup, 53.8%). The PTS was not different between subgroups (11.7° ± 3.2° in the non-OA subgroup vs. 10.6° ± 2.7° in the OA subgroup; p = 0.159). However, the non-OA subgroup had a lower NWI than the OA subgroup (0.25 ± 0.03 vs. 0.28 ± 0.02, p = 0.001). Conclusions: Patients with MD-ACL had a lower NWI and a larger PTS than patients with a normal ACL. Furthermore, the clinical and radiological features of MD-ACL differed according to the knee OA status. A narrow intercondylar notch may be more closely associated with the development of MD-ACL without OA.

Prevalence and mechanisms of anterior cruciate ligament tears in military personnel: A cross-sectional study in Iran.

BACKGROUND: Anterior cruciate ligament (ACL) tear is common in military setting; such an injury increase institutional costs and workforce strain, however, few studies have investigated the mechanism and associated factors of ACL tear specifically in a military setting. The aim of this study was to investigate the prevalence and mechanisms of ACL tears in military personnel at a military referral hospital in Iran. MATERIAL AND METHODS: This cross-sectional study examined 402 military personnel who presented with knee complaints at a single referral Iranian military hospital. The ACL injury prevalence and mechanisms were assessed by physical examination, medical records, and magnetic resonance imaging (MRI) of the knee. Data were collected by an orthopedic resident. RESULTS: Of the total 402 patients, 285 were diagnosed with ACL tears; the prevalence was 70.9%. The most common mechanism leading to ACL tear was noncontact events. The knee changing direction-knee pivoting (54%) was the most frequent lower limb status, followed by a fall with the knee in valgus position (20.7%). The most commonly associated activity was military training (63.9%) and sports activities (32.6%). The incidence of ACL injuries was higher in soldiers compared with officers during military training, but higher in officers during sports exercises (P = 0.002). Common associated injuries involved the knee meniscus and cartilage. CONCLUSION: The findings support those of previous studies, that in military personnel, the most common knee injury is damage to the ACL, most frequently through noncontact events, specifically knee pivoting, during military activities rather than sports and among soldiers. These findings help develop ACL injury prevention programs.

A comparative study on 3D printing-assisted arthroscopic IDEAL point femoral tunnel positioning for anterior cruciate ligament reconstruction versus conventional arthroscopic positioning.

BACKGROUND: This study aimed to investigate the feasibility and precision of using a 3D-printed template for femoral tunnel placement in guiding the optimal positioning of the Internal anatomical stop and Low tension maintenance (IDEAL) bone tunnel during single-bundle anterior cruciate ligament (ACL) reconstruction. METHODS: A retrospective analysis was conducted on 40 patients who underwent arthroscopic single-bundle ACL reconstruction at our hospital between April 2021 and November 2021. In the direct vision group, the IDEAL bone tunnel was positioned using radiofrequency localization directly visualized at the stump. In the 3D-printed positioning group, preoperative CT scans and Digital Imaging and Communications in Medicine (DICOM) data were employed. Following the Quadrant method by Bernard, the femoral tunnel's depth was set at 25% and its height at 29%. Postoperative plain CT scans enabled the reconstruction of 3D models for both groups. The accuracy of femoral tunnel placement was then compared. RESULTS: The central locations of the bone tunnels in the direct vision group were at a mean depth of 25.74 ± 1.84% and a height of 29.22 ± 2.97%. In the 3D printing localization group, these values were 25.39 ± 2.98% for depth and 28.89 ± 2.50% for height, respectively. No significant differences were found in tunnel positioning between the groups. Both groups demonstrated statistically significant improvements in International Knee Documentation Committee Subjective Knee Form (IKDC) and Lysholm scores postoperatively, with no significant differences observed 12 months post-surgery. CONCLUSION: The findings of this study suggest that 3D printing-assisted arthroscopic IDEAL point femoral tunnel positioning and conventional arthroscopic positioning are feasible and effective for ACL reconstruction. Using 3D printing technology to design femoral anchor points in ACL reconstruction allows for the customization of anterior fork reconstruction and precise bone tunnel positioning, supporting the goal of individualized and accurate reconstruction.

Elevated proinflammatory cytokines in response to mechanical stimulus are associated with reduced knee loading 2 years after anterior cruciate ligament reconstruction.

BACKGROUND: The aim of this study was to test the hypothesis that proinflammatory cytokines correlate with knee loading mechanics during gait following a mechanical walking stimulus in subjects 2 years after anterior cruciate ligament reconstruction. Elevated systemic levels of proinflammatory cytokines can be sustained for years after injury. Considering roughly 50% of these patients progress to Osteoarthritis 10-15 years after injury, a better understanding of the role of proinflammatory cytokines such as tumor necrosis factor-α and Interleukin-1ß on Osteoarthritis risk is needed. METHODS: Serum proinflammatory cytokines concentrations were measured in 21 subjects 2 years after unilateral ACLR from blood drawn at rest and 3.5 h after 30 min of walking. An optoelectronic system and a force plate measured subjects' knee kinetics. Correlations were tested between inflammatory marker response and knee extension and knee adduction moments. FINDINGS: Changes in proinflammatory cytokines due to mechanical stimulus were correlated (R = 0.86) and showed substantial variation between subjects in both cytokines at 3.5 h post-walk. Knee loading correlated with 3.5-h changes in tumor necrosis factor-α concentration (Knee extension moment: R = -0.5, Knee adduction moment: R = -0.5) and Interleukin-1ß concentration (Knee extension moment: R = -0.44). However, no significant changes in concentrations were observed in tumor necrosis factor-α and Interleukin-1ß when comparing baseline and post walking stimulus conditions. INTERPRETATION: The significant associations between changes in serum proinflammatory markers following a mechanical stimulus and gait metrics in subjects at risk for developing Osteoarthritis underscore the importance of investigating the interaction between biomarkers and biomechanical factors in Osteoarthritis development.

Comparison of the in vivo kinematics between robotic-assisted Bi-cruciate retaining and Bi-cruciate stabilised total knee arthroplasty.

BACKGROUND: Up to 20% of patients remain unsatisfied after total knee arthroplasty (TKA), prompting the development of new implants. Bi-Cruciate Retaining (BCR) TKA preserves both the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL), with the ACL beneficial for its proprioceptive qualities. The Bi-Cruciate Stabilised (BCS) TKA substitutes the ACL and PCL with a unique dual cam-post mechanism. Robotics improve accuracy and facilitate technically demanding TKA. METHODS: This was a retrospective case-control study recruited from two centres. Measured outcomes included kinematic analysis, proprioception, and functional outcomes. RESULTS: There was a significantly larger maximum flexion angle and range of flexion to extension in sit-to-stand and stairs in BCR when compared to BCS. Further analysis revealed more similarities between BCR and normal native knees. Proprioception and functional scores did not have any statistical difference. CONCLUSION: BCR TKA demonstrated better knee flexion in weight-bearing active range of motion and showed similarities with normal knee kinematics.

The effect of stroboscopic visual disruption on static stability measures in anterior cruciate ligament reconstructed individuals.

BACKGROUND: Those who undergo ACL reconstruction are at an increased risk of suffering a second ACL injury. A suggested rationale for the increased injury risk is sensory reweighting to the visual system to compensate for a lack of somatosensory information from the knee. Understanding this proposed visual reliance may help clinicians improve return to sport outcomes and reduce the risk of a subsequent ACL injury. METHODS: Thirteen ACL reconstructed individuals and thirteen matched controls completed two common static postural control assessments under three different visual conditions; eyes open, low visual disruption, and high visual disruption. Center of pressure data was collected for 30 s using force plates. Static postural stability was evaluated using the following: 1) root mean square distance, 2) mean velocity, 3) sway area, and 4) mean frequency. FINDINGS: No significant interactions between group and vision were observed. Significant differences between groups were observed for mean frequency in the double-limb stance (p < .05). Additionally, significant differences were observed for visual conditions in both double-limb (mean velocity; p < .05) and single-limb stances (root mean square distance, mean velocity, sway area, and mean frequency; p < .05). INTERPRETATION: The findings of the current study suggest that ACL reconstructed individuals, who are at least two years removed from surgery, do not rely on visual information to a greater extent than controls during static postural stability assessments. Stroboscopic glasses may be a cost-effective alternative for rehabilitation purposes compared to the traditional binary eyes open vs. eyes closed methods.

Optimal tibial tunnel angulation for anatomical anterior cruciate ligament reconstruction using transtibial technique.

Numerous studies have suggested that the primary cause of failure in transtibial anterior cruciate ligament reconstruction (ACLR) is often attributed to non-anatomical placement of the bone tunnels, typically resulting from improper tibial guidance. We aimed to establish the optimal tibial tunnel angle for anatomical ACLR by adapting the transtibial (TT) technique. Additionally, we aimed to assess graft bending angle (GBA) and length changes during in vivo dynamic flexion of the knee. Twenty knee joints underwent a CT scan and dual fluoroscopic imaging system (DFIS) to reproduce relative knee position during dynamic flexion. For the single-legged lunge, subjects began in a natural standing position and flexed the right knee beyond 90° When performing the lunge task, the subject supported the body weight on the right leg, while the left leg was used to keep the balance. The tibial and femoral tunnels were established on each knee using a modified TT technique for single-bundle ACLR. The tibial tunnel angulation to the tibial axis and the sagittal plane were measured. Considering that ACL injuries tend to occur at low knee flexion angles, GBA and graft length were measured between 0° and 90° of flexion in this study. The tibial tunnel angulated the sagittal plane at 42.8° ± 3.4°, and angulated the tibial axis at 45.3° ± 5.1° The GBA was 0° at 90° flexion of the knee and increased substantially to 76.4 ± 5.5° at 0° flexion. The GBA significantly increased with the knee extending from 90° to 0° (p < 0.001). The ACL length was 30.2mm±3.0 mm at 0° flexion and decreased to 27.5mm ± 2.8 mm at 90° flexion (p = 0.072). To achieve anatomic single-bundle ACLR, the optimal tibial tunnel should be angulated at approximately 43° to the sagittal plane and approximately 45° to the tibial axis using the modified TT technique. What's more, anatomical TT ACLR resulted in comparable GBA and a relatively constant ACL length from 0° to 90° of flexion. These findings provide theoretical support for the clinical application and the promotion of the current modified TT technique with the assistance of a robot to achieve anatomical ACLR.

Effects of sex differences on osteoarthritic changes after anterior cruciate ligament reconstruction in rats.

The prevalence of primary osteoarthritis is higher in females than males. However, it remains unclear if there are sex differences in the incidence of post-traumatic osteoarthritis after anterior cruciate ligament (ACL) reconstruction. In this study, we aimed to investigate the effects of sex on osteoarthritic changes after ACL reconstruction using an animal model. Rats were divided into the following four groups: male control, male ACL reconstruction, female control, and female ACL reconstruction. ACL reconstruction surgery was performed on the right knees of rats in the ACL reconstruction groups, while rats in the control groups did not undergo knee surgery. At 1, 4, and 12 weeks after surgery, cartilage degeneration in the medial tibial plateau and osteophyte formation in the proximal tibia were histologically assessed. After ACL reconstruction, an increase in the Mankin score, cartilage fissures, and osteophyte formation were detected within 12 weeks in both male and female rats, with similar degrees of these changes between males and females. However, changes in cartilage thickness and chondrocyte density after ACL reconstruction differed between males and females. Cartilage thickening was observed in male rats but not in female rats. The increase in chondrocyte density in the anterior region was detected in both males and females but was more pronounced in female rats. In conclusion, osteoarthritic changes were observed after ACL reconstruction in both male and female rats, but differences in changes in cartilage thickness and chondrocyte density were observed between males and females.

Establishment of a Posttraumatic Osteoarthritis Model in Mice Induced by Noninvasive Anterior Cruciate Ligament Tear.

BACKGROUND: Animal models that use open surgical transection of the anterior cruciate ligament (ACL) do not accurately simulate the clinical condition regarding the pivot-shift mechanism and the associated inflammatory response that occurs before reconstruction. PURPOSE/HYPOTHESIS: The purpose was to characterize a reproducible manual, nonsurgical method to mimic an isolated ACL tear in a clinically relevant model and to evaluate the development of progressive posttraumatic osteoarthritis due to ACL injury. It was hypothesized that the ACL could be reproducibly torn with minimal damage to other ligaments and that there would be progressive development of degenerative joint disease after ACL injury. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 37 mice (strain C57BL/6) were used to compare the manual procedure with sham surgery (sham group; n = 10) and with the established surgical ACL transection (ACLT) procedure (surgical group; n = 27). In the sham group, a closed manual procedure was performed on the right knee and sham surgery on the left knee. In the surgical group, the closed manual procedure was performed on the right knee and surgical ACLT on the left knee. Dissection using India ink, histological assessment with safranin O and hematoxylin-eosin staining, radiological evaluation through radiographs and microfocus computed tomography scans, and gait analyses were performed to assess cartilage/ligament status. Osteoarthritis Research Society International (OARSI) and synovitis scores, anterior tibial translation, range of motion, bone microstructure, osteophyte volume, and pain were assessed at 2, 4, and 8 weeks postoperatively. RESULTS: The manual procedure successfully resulted in an ACL rupture and associated meniscal injury. The posterior cruciate, lateral collateral, and medial collateral ligaments were intact in all dissected knees. Two weeks after ACL tear, the surgical group showed a significantly higher synovitis score, whereas 8 weeks after ACL tear, the manual group showed a significantly higher volume of osteophytes. No significant differences were found between the groups in terms of OARSI score, anterior tibial translation, range of motion, bone microstructure computed tomography values, and stride distance/irregularity. CONCLUSION: This procedure can be used to create an ACL tear model without causing grossly evident injuries to other ligaments and avoiding the risk of cartilage damage from surgical instruments. CLINICAL RELEVANCE: This procedure offers a more clinically relevant ACL tear model and facilitates simple, inexpensive, and reproducible development of posttraumatic osteoarthritis.

Biomechanical and Histological Study of Retrieved LARS Synthetic Ligaments.

BACKGROUND: Synthetic grafts have been used for a number of years in anterior cruciate ligament (ACL) reconstruction surgery. One of the more recent additions to the stable of synthetic ligaments is the Ligament Augmentation and Reconstruction System (LARS) ligament. PURPOSE: To analyze the biomechanics and histology of LARS grafts retrieved due to failure of the device. STUDY DESIGN: Descriptive laboratory study. METHODS: A total of 22 LARS ligament grafts that were explanted from patients were sent for analysis. Five new, unused samples of the standard LARS ACL graft were also analyzed. Biomechanical testing was performed: ultimate tensile force, force versus displacement, and stress versus strain were recorded. Histopathological examination was performed looking for degree of fibrous tissue ingrowth as well as the presence of a foreign body reaction. RESULTS: Of the 22 grafts retrieved, 14 were used for ACL grafts, 1 for a lateral collateral ligament graft, 2 for medial collateral ligament grafts, 4 for gluteal tendon augmentation, and 1 for a supraspinatus augmentation. A severe foreign body reaction was found in 86% of the grafts (18/22) and a mild foreign body reaction in the remaining 14% (4/22). Tissue ingrowth was minimal in the majority of ACL grafts; the other grafts showed moderate tissue ingrowth. Maximal tensile force was significantly higher for the new ACL grafts (mean ± SD, 1667 ± 845 N) compared with the retrieved grafts (897 ± 395 N; P < .05). CONCLUSION: This study demonstrated that the vast majority of retrieved LARS artificial ligaments had a florid foreign body reaction. There was minimal tissue ingrowth in ACL grafts and moderate ingrowth in other grafts. Retrieved grafts had a decreased ultimate tensile force, which increased their risk of rupture. CLINICAL RELEVANCE: Surgeons should be cautious in choosing to use these grafts in reconstructive surgery for patients.

A study regarding the anterior cruciate ligament remnant: Differences in balance and postural control between remnant-preserving and remnant-non-preserving patients

Introduction: The anterior cruciate ligament (ACL) is the most frequently injured ligament of the knee. However, quantitative studies on evaluate the postural control influence resulted from the ACL remnant preservation or not are scarce. The aim of this study is to evaluate the postural control of patients submitted to ACL reconstruction with and without preservation of the injured remnant in pre and postoperative periods.MethodsEighteen patients underwent ACL reconstruction and separated into 2 groups according to the preservation or not of the remnant: (I) submitted to ACL reconstruction with preservation of the remnant (10 patients); (II) submitted to ACL reconstruction without preservation of the remnant (8 patients). They were assessed using the Lysholm score and force plate, which evaluated the patient's postural stability for remnant and non-remnant preservation in ACL reconstruction surgery.ResultsGroup I showed statistically significant subjective and objective improvements, both at 3 and 6 months. Additionally, improvement of the Lysholm test at 6 months in Group II was also statistically significant. Furthermore, the results of the Friedman test for the VCOP and VY variables of Group I, with support of the injured side in the force plate, showed a statistically significant difference both for pre and postoperative period at 3 months, compared to the 6-month postoperative period. The variables EAC and VX were statistically different for Group II, considering the preoperative period, 3 and 6 months postoperatively.ConclusionPreserving the ACL remnant in patients with ACL injuries has a positive impact on postural stability during recovery.(AU)

Introducción: El ligamento cruzado anterior (LCA) es el ligamento de la rodilla que se lesiona con mayor frecuencia. Sin embargo, escasean los estudios cuantitativos sobre la evaluación de la influencia del control postural derivada de la preservación, o no, del remanente del LCA. El objetivo de este estudio es evaluar el control postural de los pacientes sometidos a la reconstrucción del LCA, con y sin preservación del remanente lesionado, en los periodos previo y posterior a la cirugía.MétodosDieciocho pacientes sometidos a reconstrucción del LCA separados en 2 grupos, de acuerdo con la preservación o no preservación del remanente: I) sometidos a reconstrucción del LCA con preservación del remanente (10 pacientes), y II) sometidos a reconstrucción del LCA sin preservación del remanente (8 pacientes). Los pacientes fueron evaluados utilizando la puntuación de Lysholm y una placa de aplicación de fuerza, que evaluó la estabilidad postural del paciente para la preservación y no preservación del remanente en la cirugía de reconstrucción del LCA.ResultadosEl grupo I mostró mejoras subjetivas y objetivas estadísticamente significativas, transcurridos 3 y 6 meses. Además, la mejora de la prueba de Lysholm transcurridos 6 meses en el grupo II fue también estadísticamente significativa. Asimismo, los resultados de la prueba de Friedman para las variables VCOP y VY en el grupo I, con apoyo del lado lesionado en la placa de aplicación de fuerza, reflejaron una diferencia estadísticamente significativa en ambos períodos pre y postoperatorio transcurridos 3 meses, en comparación con el período postoperatorio transcurridos 6 meses. Las variables EAC y VX fueron estadísticamente diferentes para el grupo II, considerando el periodo preoperatorio, y los 3 y 6 meses postoperatorios.ConclusiónPreservar el remanente del LCA en los pacientes con lesiones en dicho ligamento tiene un impacto positivo en la estabilidad postural durante la recuperación.(AU)

Load Sharing of the Deep and Superficial Medial Collateral Ligaments, the Effect of a Partial Superficial Medial Collateral Injury, and Implications on ACL Load.

BACKGROUND: Injuries to the deep medial collateral ligament (dMCL) and partial superficial MCL (psMCL) can cause anteromedial rotatory instability; however, the contribution of each these injuries in restraining anteromedial rotatory instability and the effect on the anterior cruciate ligament (ACL) load remain unknown. PURPOSE: To investigate the contributions of the different MCL structures in restraining tibiofemoral motion and to evaluate the load through the ACL after MCL injury, especially after combined dMCL/psMCL injury. STUDY DESIGN: Controlled laboratory study. METHODS: Sixteen fresh-frozen human cadaveric knees were tested using a 6 degrees of freedom robotic simulator. Tibiofemoral kinematic parameters were recorded at 0°, 30°, 60°, and 90° of knee flexion for the following measurements: 8-N·m valgus rotation, 4-N·m external tibial rotation (ER), 4-N·m internal tibial rotation, and a combined 89-N anterior tibial translation and 4-N·m ER for both anteromedial rotation (AMR) and anteromedial translation (AMT). The kinematic parameters of the 3 different MCL injuries (dMCL; dMCL/psMCL; dMCL/superficial MCL (sMCL)) were recorded and reapplied either in an ACL-deficient joint (load sharing) or before and after cutting the ACL (ACL load). The loads were calculated by applying the principle of superposition. RESULTS: The dMCL had the largest effect on reducing the force/torque during ER, AMR, and AMT in extension and the psMCL injury at 30° to 90° of knee flexion (P < .05). In a comparison of the load through the ACL when the MCL was intact, the ACL load increased by 46% and 127% after dMCL injury and combined dMCL/psMCL injury, respectively, at 30° of knee flexion during ER. In valgus rotation, a significant increase in ACL load was seen only at 90° of knee flexion. CONCLUSION: The psMCL injury made the largest contribution to the reduction of net force/torque during AMR/AMT at 30° to 90° of flexion. Concomitant dMCL/psMCL injury increased the ACL load, mainly during ER. CLINICAL RELEVANCE: If a surgical procedure is being considered to treat anteromedial rotatory instability, then the procedure should focus on restoring sMCL function, as injury to this structure causes a major loss of the knee joint's capacity to restrain AMR/AMT.