Laterally shifted tibial tunnel can be the risk of residual knee laxity for double-bundle anterior cruciate ligament reconstruction.

PURPOSE: To elucidate the relationship between graft tunnel position and knee laxity in the cases of double-bundle ACL reconstruction. METHODS: Total of 132 cases were included. Femoral and tibial tunnels were evaluated by quadrant method on 3D-CT. As additional reference of tibia, the distances from medial tibial spine to the tunnel center (DMS) and from Parsons' knob to the tunnel center (DPK) were evaluated; %DMS/ML and %DPK/AP were calculated (ML and AP: mediolateral and anteroposterior width of tibial plateau). Preoperative and postoperative (1 year from surgery) stabilities were evaluated by Lachman and pivot-shift procedures. If there was ≥ 2 mm side-to-side difference, the subject was defined as having anterior knee laxity (AKL); if the pivot-shift phenomenon was observed with IKDC grade ≥ 1, there was rotatory knee laxity (RKL). Multiple logistic regression analysis was conducted with the prevalence of AKL or RKL as the dependent variable and with tunnel positions as the independent variables. RESULTS: Overall, 21 subjects (15.9%) showed AKL, and 15 subjects (11.4%) showed RKL. Those with postoperative laxity showed higher %DMS/ML and higher femoral position than those without laxity. Regarding posterolateral bundle, logistic regression model estimated that %DMS/ML was associated with the prevalence of AKL (B = 0.608; p < 0.001) and RKL (B = 0.789; p < 0.001); %high-low femoral tunnel position (B = - 0.127; p = 0.023) was associated with that of RKL. CONCLUSION: There was the risk of residual knee laxity in ACL-reconstructed knee when tibial tunnel shifted more laterally or higher femoral tunnel was created with regard to posterolateral bundle. LEVEL OF EVIDENCE: III.

Biomechanical analysis of bioabsorbable suture anchors for rotator cuff repair using osteoporotic and normal bone models.

BACKGROUND: This study aimed to compare the failure load of suture anchors used in rotator cuff repair between normal and osteoporotic bone models. METHODS: A total of 16 anchors made from metal (TwinFix Ti 5.0 or 6.5 mm, Corkscrew FT 4.5, 5.5, or 6.5 mm), polyether ether ketone (HEALICOIL PK [HC-PK] 4.5 or 5.5 mm, SwiveLock PK 4.75 or 5.5 mm), or bioabsorbable material (HEALICOIL RG [HC-RG] 4.75 or 5.5 mm, Corkscrew Bio 4.75, 5.5, or 6.5 mm, SwiveLock BC 4.75 or 5.5 mm) were included. Moreover, 10- and 5-pounds per cubic foot (pcf) Sawbone® models were set as normal and osteoporotic cancellous bone models, respectively. Pullout testing was performed in parallel to the insertion axis at a displacement rate of 12.5 mm/s using a universal testing machine. To evaluate the change in failure load between the two Sawbone® models with different densities, the remaining failure load ratio (RFLR) was defined as the ratio of the failure load in 10 pcf to that in 5 pcf. RESULTS: In the 10-pcf Sawbone®, TwinFix Ti 6.5 mm showed the highest mean failure load (304.0 ± 15.2 N). In the 5-pcf Sawbone® model, HC-PK 5.5 mm showed the highest failure load (146.3 ± 5.8 N). Among anchors with the same diameter, HC-PK and HC-RG showed a significantly higher failure load than other anchors in the 10- and 5-pcf Sawbone® models. HC-PK 5.5 mm (62.1%) and HC-PK 4.5 mm (51.1%) have the highest RFLR among anchors with the same diameter. CONCLUSIONS: HC-PK and HC-RG showed higher failure load than the other anchors in both normal and osteoporotic bone models, except for TwinFix Ti 6.5 mm in the 10-pcf Sawbone® model. Based on our results, bioabsorbable anchors had sufficient failure load for rotator cuff repair in addition to bioabsorbability.

A Novel Quantitative Evaluation of Bone Formation After Opening Wedge High Tibial Osteotomy Using Tomosynthesis.

This study aimed to establish and validate a novel evaluation method using digital tomosynthesis to quantify bone formation in the gap after opening wedge high tibial osteotomy (OW-HTO). We retrospectively analyzed bone formation in the gap in 22 patients who underwent OW-HTO using digital tomosynthesis at 1, 2, 3, 6, 9, and 12 months postoperatively. Bone formation was semi-quantitatively assessed using the modified van Hemert's score and density measurements on digital tomosynthesis images. The gap filling value (GFV) was calculated as the ratio of the intensities of the opening gap and the tibial shaft. In addition, the relationship between the modified van Hemert's score and GFV was evaluated. The reproducibility of GFV had an interclass correlation coefficient (ICC [1,2]) of 0.958 for intraobserver reliability and an ICC (2,1) of 0.975 for interobserver reliability. The GFV increased in a time-dependent manner and was moderately correlated with the modified van Hemert's score (r = 0.630, p < 0.001). The GFV plateaued at 6 months postoperatively. In addition, the GFV was higher in patients with a modified van Hemert's score of 2 than in patients with a modified van Hemert's score of 3 (p = 0.008). The GFVs obtained using digital tomosynthesis can be used to assess postoperative bone formation in the opening gap after OW-HTO with high accuracy and reproducibility.

Hyaluronidase and degranulation inhibitors from the edible roots of Oenanthe javanica including seric acids F and G that were obtained by heating.

Oenanthe javanica is a vegetable grown in East Asia and Australia in which the roots and aerial parts are boiled together to make certain traditional dishes. Nineteen compounds (1-19) were isolated from O. javanica roots and the chemical structures of 2 new norlignans were determined. The inhibitory effects of the compounds on hyaluronidase and degranulation in RBL-2H3 cells were evaluated to determine antiallergic and antiinflammation activities. Saponins (2-4) and the new norlignan seric acid G (12) were among the active compounds identified. Seric acid G (12), a methoxy derivative of seric acid F (11), was obtained as an interconverting mixture of 3:1 trans-cis isomers. Seric acids F and G (11, 12) were derived from seric acids C (10) and E, respectively, by decarboxylation and dehydration reactions that occurred during heating. It was confirmed by HPLC analysis that all eleven of the O. javanica cultivars contained seric acid C (10).

Influence of microwave annealing on optical and electrical properties of plasma-induced defect structures in Si substrate.

The authors investigate the effects of microwave annealing (MWA) on the recovery of plasma process-induced ion-bombardment damage in Si substrates. For damage creation, Ar discharges by a capacitively coupled plasma etcher are used. For damage repairing, the MWA or a rapid thermal annealing (RTA) are conducted. The authors employ spectroscopic ellipsometry (SE), photoreflectance spectroscopy (PRS), and capacitance-voltage (C-V) measurement to analyze the damaged structures. Recovery of the damage is discussed by comparing the obtained parameters before and after the annealing processes. In the SE analysis, the change in the real part of dielectric constant (Δεr) is investigated. The Δεr spectral peak around 3.4 eV decreases with an increase in the annealing temperature (Ta) for both MWA and RTA, indicating the decrease in the density of defects created in the Si substrate. In the PRS analysis, the spectral peak intensity is found to decrease by the plasma exposure, and then to increase with Ta, which implies the recovery of the Si crystalline structure by MWA as well as by RTA. In the C-V measurement, the voltage shift (ΔVb) in the respective C-V curves is used as a measure of the number of defects present in the surface and interface damaged regions. The ΔVb in the negative bias direction is observed after the plasma exposure for all damaged structures, while after annealing the ΔVb in the positive bias direction is confirmed, suggesting the recovery of the damage in the surface and interface regions. Moreover, it is experimentally found that MWA induces larger |ΔVb| than RTA. These findings indicate the decrease in carrier trap sites in the surface and interface regions of damaged structures, and that MWA is more effective in repairing such damage than RTA. The authors propose a model explaining these mechanisms where defect-induced dipole moments that interact with the incident microwave are considered. The present results draw a new damage-recovery picture by MWA, in particular, for plasma-induced damage in surface and interface regions of Si substrates.

Concomitant Lateral Meniscus Tear is Associated with Residual Rotatory Knee Instability 1 Year after Anterior Cruciate Ligament Reconstruction: Case-cohort Study.

Lateral meniscus tear (LMT) accompanied by anterior cruciate ligament (ACL) injuries has been reported to provoke rotatory instability of the affected knee joint. Unfortunately, these previous papers did not determine whether LMT-derived rotatory knee instability is residual because only preoperative or time zero data exists. This study aimed to longitudinally investigate how the prevalence of comorbid LMT is associated with residual rotatory knee instability (RKI) 1 year after ACL reconstruction (ACLR). A total of 327 patients who underwent double-bundle ACLR (average age: 23.4 years, body mass index: 23.5 kg/m2, 215 females). The patients were divided into three groups based on arthroscopy: 1) intact lateral meniscus (LM); 2) unrepaired LMT; 3) repaired LMT. At the 1-year follow-up, the pivot-shift test was performed. The prevalence of RKI, determined according to IKDC grades (grade ≥1 denoted RKI), was compared with chi-square or Fisher's exact tests. Thirty-eight patients (11.6%) had RKI; 203 subjects (62.1%) showed LMT, and 124 patients were diagnosed with an intact LM. Out of the 203 patients, 79 (38.9%) underwent LM repair. RKI was more prevalent in the LMT group than in the intact group (13.8% versus 8.1%, p = 0.117; Odds ratio: 1.499 [95%CI: 0.864 - 2.600]). In addition, the prevalence of RKI was significantly higher in the LM-repair group than in the intact-LM group (17.7% versus 8.1%, p = 0.038; Odds Ratio: 2.455 [95%CI: 1.032 - 5.842]). Medial meniscus tear (MMT) was detected in 113 patients (34.6%); RKI prevalence was not statistically different between the intact-MM group and the MMT group (12.2% versus 10.6%, p = 0.681). The current cohort study clarified that LMT comorbid with ACL injury was longitudinally associated with increased RKI prevalence 1 year after ACLR. Therefore, patients who underwent both ACLR and LM repair demonstrated a significantly higher prevalence of residual RKI.

Biomechanical Analysis of Unstable Osteochondral Fragment Fixation Using Three Different Techniques: Osteochondral Plug, Bioabsorbable Pin, and Suture Anchor with Tape.

Purpose: To compare the initial fixation strength of osteochondral fragment fixations using osteochondral plugs, bioabsorbable pins, and knotless suture anchors. Methods: Eighteen fresh-frozen immature (6 month old) porcine knees were used. An osteochondral fragment, cut from the articular surface of the medial femoral condyle to achieve a thickness of 5 mm, was used to mimic the unstable osteochondral fragment. It was fixed using three techniques, including two osteochondral plugs (osteochondral plug group), four full-threaded poly l-lactic acid pins (bioabsorbable pin group), and three suture anchors with a 2-0 tape (suture anchor group). Tensile loads at displacements of 1 and 2 mm and ultimate failure load were measured at a cross-head speed of 100 mm/min, and the variables of the three groups were compared statistically using a one-way ANOVA with Tukey's honestly significant difference test. Results: There was no significant difference in the tensile load to achieve 1-mm displacement. The load to achieve 2-mm displacement and the ultimate failure load were significantly greater in the suture anchor group than the osteochondral plug group and the bioabsorbable pin group. Conclusions: Single-pull destructive testing of a fixed articular osteochondral fragment with the force perpendicular to the articular surface, demonstrated no statistical difference in the tensile load to achieve 1-mm displacement, but the load to achieve 2-mm displacement was significantly greater for the three suture anchor-interlocking 2-0 tape constructs than the dual osteochondral plug fixation and the four bioabsorbable pin fixation constructs. Additionally, the three suture anchor-interlocking 2-0 tape construct's mean single-pull failure load was greater than other two fixation procedures. Clinical Relevance: To achieve osteochondral fragment union, sufficient fixation strength is critical. However, the initial fixation strength of osteochondral plugs, bioabsorbable pins, and knotless suture anchors for unstable osteochondral lesions remains unclear.

Failure load of the femoral insertion site of the anterior cruciate ligament in a porcine model: comparison of different portions and knee flexion angles.

BACKGROUND: This study compared the failure load of the femoral insertion site of the anterior cruciate ligament between different portions and knee flexion angles. METHODS: In total, 87 fresh-frozen, porcine knees were used in this study. Three knees were used for histological evaluation; the remaining 84 knees were randomly divided into 4 groups: anterior anteromedial bundle, posterior anteromedial bundle, anterior posterolateral bundle, and posterior posterolateral bundle groups (n=21 per group). The anterior cruciate ligament femoral insertion site was divided into these four areas and excised, leaving a 3-mm square attachment in the center of each bundle. Tibia-anterior cruciate ligament-femur complexes were placed in a material testing machine at 30°, 120°, and 150° of knee flexion (n=7), and the failure load for each portion was measured under anterior tibial loading (0.33 mm/s). RESULTS: Histological study showed that the anterior cruciate ligament femoral insertion site consisted of direct and indirect insertions. Comparison of the failure load between the knee flexion angles revealed that all the failure loads decreased with knee flexion; significant decreases were observed in the failure load between 30 and 150° knee flexion in the posterior anteromedial bundle and posterior posterolateral bundle groups. Comparison of the failure load according to different portions revealed a significant difference between the anteromedial and posterolateral bundle groups at 150° of knee flexion, but no significant difference among the groups at 30° of flexion. CONCLUSIONS: Although the failure load of the posterior portion decreased significantly in the knee flexion position, it (mainly consisting of indirect insertion) plays a significant role against anterior tibial load in the knee extension position; this appears to be related to the characteristics of the insertion site. Reflecting the complex structure and function of the ACL, this study showed that the failure load of the femoral insertion site varies with differences in positions and knee flexion angles.

Tibial eminence fracture with midsubstance anterior cruciate ligament tear in a 10-year-old boy: A case report.

INTRODUCTION: There are few reports about tibial eminence fractures with a concomitant midsubstance ACL tear in children. In this report, we present a case of a tibial eminence fracture with an ACL midsubstance tear in a 10-year-old boy. PRESENTATION OF CASE: The boy twisted his right knee and was seen at our facility 8 days later. Magnetic resonance imaging revealed an osteochondral fragment in the intercondylar fossa and a high-intensity area in the ACL midsubstance. This injury was diagnosed as a type III tibial eminence fracture by Meyers and McKeever classification. On the 10th day after the injury, the patient underwent arthroscopic reduction and fixation. During arthroscopy proximally displaced avulsion fragment in the intercondylar fossa was found. Although the continuity of the anteromedial bundle of the ACL was confirmed, the posterolateral bundle was completely torn and the tension of ACL was weakened. The fragment and torn ACL were fixed with pull out suture. One year after the operation, the patients can play sports without any pain. DISCUSSION: This case demonstrates that a tibial eminence fracture with an ACL midsubstance tear can occur in a child. Despite the rarity of such cases, preoperative MRI studies are necessary to detect and diagnose them. MRI also allows surgeons to identify cases that might need ACLR. CONCLUSION: It should be noted that a midsubstance ACL tear can occur with a tibial eminence fracture even in skeletally immature patients, and that preoperative MRI is necessary to diagnose and select the appropriate treatment.