Enhancement of Steel Sandwich Sheet Adhesion Using Mechanical Interlocking Structures Formed by Electrochemical Etching.

Steel sandwich sheets (steel-polymer-steel), which are composed of lightweight polymers bonded on both sides with rigid steel sheets, have recently been developed as functional lightweight materials. In this study, a steel sandwich sheet (electrogalvanized (EG) steel sheet-polypropylene (PP)-EG steel sheet) with improved normal adhesion is fabricated without adhesives. Instead, adhesion is achieved via mechanical interlocking between the etched EG steel sheets and PP. Hierarchical structures were formed on the EG steel sheet surface by electrochemical etching to attain effective mechanical interlocking for improving normal adhesion without any adhesives. In the case of the EG steel sheet etched at 6 V for 7 s, a high fraction (∼35%) of holes (size: <1 µm2) with nanoscale scalloped structures was formed on the EG steel sheet surface. The normal adhesion test result of the fabricated steel sandwich sheet showed that the adhesion strength increased from virtually 0 (bare) to 559.6 kPa as a result of mechanical interlocking. The results of the focused ion beam-scanning electron microscopy and energy-dispersive spectrometry analyses confirmed the cohesive failure of PP resulting from the successful mechanical interlocking of PP with the holes formed on the etched EG steel sheet. To examine the effect of hierarchical structures on the normal adhesion of the steel sandwich sheet, finite element analysis was implemented.

Effect of Lower-Extremity Angular Imbalance on Foot and Ankle Pain in Patients With Genu Varus Deformity.

When there is a varus knee deformity, the ankle and foot compensate. However, the association between pain and angular change in the compensatory mechanism is not well understood. Therefore, we investigated the relationship between pain and angular change of the lower extremity in genu varus patients. Standing whole-lower-leg plain radiographs of 127 legs (77 patients) with >4° of genu varum were evaluated. Pain was assessed separately at the ankle, forefoot, and hindfoot. Knee, ankle, and subtalar joint angles were measured. Patients were divided into 3 groups according to the degree of lower leg angular imbalance (group 1, mild; group 2, moderate; group 3, severe). The presence of multiple pain locations differed significantly between groups and was significantly higher in group 3 than group 1 (p = .0061). Likewise, the subtalar angle was significantly more varus in group 3 than group 1 (p = .012). In conclusion, an unbalanced lower extremity with genu varum was associated with multiple foot and ankle pain, and the subtalar joint played a primary role in compensation for genu varum deformity.

Corrigendum to: Effects of salmon DNA fraction in vitro and in a monosodium iodoacetate-induced osteoarthritis rat model.

[This corrects the article on p. 163 in vol. 22, PMID: 29520169.].

Effects of salmon DNA fraction in vitro and in a monosodium iodoacetate-induced osteoarthritis rat model.

PRF001 is a fragmented DNA polymer extracted from the testes of salmon. The purpose of this study was to assess the anti-inflammatory effect of PRF001 in vitro as well as the protective effect of PRF001 intake against arthritis in a rat model. In vitro, cell survival and inflammatory markers after H2O2 treatment to induce cell damage were investigated in CHON-001 cells treated with different concentrations of PRF001. In vivo, osteoarthritis was induced by intra-articular injection of monosodium iodoacetate (MIA) into the knee joints of rats. After consumption of PRF001 (10, 50, or 100 mg/kg) for 4 weeks, inflammatory mediators and cytokines in articular cartilage were investigated. In vitro, the levels of inflammatory markers, IL-1ß, TNF-α, COX-2, iNOS, and PGE2, were significantly suppressed by PRF001 treatment. In vivo, the inflammatory mediators and cytokines, IL-1ß, p-Erk1/2, NF-κB, TNF-α, COX-2, and PGE2, as well as MMP3 and MMP7, which have catabolic activity in chondrocytes, were decreased in the MIA-induced osteoarthritic rats following intake of PRF001. Histological analysis revealed that PRF001 had a protective effect on the articular cartilage. Altogether, these results demonstrated that the anti-inflammatory property of PRF001 contributes to its protective effects in osteoarthritis through deregulating IL-1ß, TNF-α, and subsequent signals, such as p-Erk1/2, NF-κB, COX-2, PGE2, and MMPs.

Does Sacral Slanting Affect Postoperative Shoulder Balance in Patients With Lenke Type 2A Adolescent Idiopathic Scoliosis?

OBJECTIVE: Even minor sacral slanting can influence T1 tilt and shoulder balance. Yet, the relationship between sacral slanting and postoperative shoulder imbalance (PSI) has not been previously explored. To determine risk factors for PSI in Lenke 2A adolescent idiopathic scoliosis (AIS) patients, with an emphasis on sacral slanting. METHODS: The study encompassed 96 consecutive patients who had undergone posterior correction and fusion surgery for Lenke type 2A AIS. Patients were grouped into PSI(+) and PSI(-) based on postoperative outcomes. Additionally, they were classified into left-sided slanting, no slanting, and right-sided slanting groups according to the degree of sacral slanting. Various radiological measures were compared. RESULTS: Patients in the PSI(+) group exhibited a smaller preoperative proximal thoracic curve and a higher main thoracic curve correction rate than those in the PSI(-) group. The presence or absence of sacral slanting did not exhibit a significant variation in PSI occurrence. However, the right-sided sacral slanting group showed a larger delta radiologic shoulder height compared to the other 2 groups (7.1 mm vs. 1.5 & 3.3 mm). CONCLUSION: Sacral slanting was not directly linked to the development of PSI. Despite the common postoperative elevation of the left shoulder, the shoulder height differences decreased over the follow-up period. Especially in cases with a right-sided tilted sacrum, the PSI demonstrated progressive improvement, with an associated increase in the rightward distal wedging angle, leading to distal adding-on.

Efficacy and safety of oblique posterior endplate resection for wider decompression (trumpet-shaped decompression) during anterior cervical discectomy and fusion.

OBJECTIVE: Anterior cervical discectomy and fusion (ACDF) provides a limited workspace, and surgeons often need to access the posterior aspect of the vertebral body to achieve sufficient decompression. Oblique resection of the posterior endplate (trumpet-shaped decompression [TSD]) widens the workspace, enabling removal of lesions behind the vertebral body. This study was conducted to evaluate the efficacy and safety of oblique posterior endplate resection for wider decompression. METHODS: In this retrospective study, 227 patients who underwent ACDF for the treatment of cervical myelopathy or radiculopathy caused by spondylosis or ossification of the posterior longitudinal ligament and were followed up for ≥ 1 year were included. Patient characteristics, fusion rates, subsidence, and patient-reported outcome measures, including the neck pain visual analog scale (VAS) score, arm pain VAS score, and Neck Disability Index (NDI), were assessed. Patients who underwent TSD during ACDF (TSD group) and those who underwent surgery without TSD (non-TSD group) were compared. RESULTS: Fifty-seven patients (25.1%) were included in the TSD group and 170 patients (74.9%) in the non-TSD group. In the TSD group, 28.2% ± 5.5% of the endplate was resected, and 26.0% ± 6.1% of the region behind the vertebral body could be visualized via the TSD technique. The resection angle was 26.9° ± 5.9°. The fusion rate assessed on the basis of interspinous motion, intragraft bone bridging, and extragraft bone bridging did not significantly differ between the two groups. Furthermore, there were no significant intergroup differences in subsidence. The patient-reported outcome measures at the 1-year follow-up were also not significantly different between the groups. CONCLUSIONS: TSD widened the workspace during ACDF, and 26% of the region posterior to the vertebral body could be accessed using this technique. The construct stability was not adversely affected by TSD as demonstrated by the similar fusion and subsidence rates among patients who underwent TSD and those who did not. Therefore, TSD can be safely applied during ACDF when compressive lesions extend behind the vertebral body and are not limited to the disc space, enabling adequate decompression without disrupting the construct stability.

Feasibility of CaO-SiO2-P2O5-B2O3 Bioactive Glass Ceramic Cage in Anterior Cervical Diskectomy and Fusion.

BACKGROUND: CaO-SiO2-P2O5-B2O3 bioactive glass ceramic (BGC) is known to chemically bond with bones by forming a hydroxyapatite layer and inducing osteoblastic differentiation. This study was conducted to compare the clinical outcomes, radiographic outcomes, and safety of a CaO-SiO2-P2O5-B2O3 BGC cage in anterior cervical diskectomy and fusion (ACDF) with those of an allograft interbody spacer. METHODS: A total of 63 patients who underwent 2-level ACDF to treat degenerative cervical radiculopathy/myelopathy were reviewed. Results from 26 patients who were recruited prospectively using CaO-SiO2-P2O5-B2O3 BGC as a cage material (BGC group) were compared with a historical control group of 37 patients who underwent surgery using an allograft (allograft group). Fusion rates, subsidence, and adjacent segment degeneration were compared between the groups. Demographic data, fusion rates, visual analog scale (VAS) scores for neck or arm pain, Neck Disability Index (NDI) scores, and complications were also compared. RESULTS: Fusion rates were 88.5% when assessed by interspinous motion and 92.3% when assessed by intragraft bone bridging in the BGC group at 12-month follow-up. The neck pain or arm pain VAS scores and NDI scores significantly improved in both groups. No material-related complications were observed in the BGC group, such as graft resorption and breakage. Fusion rates, subsidence, neck pain or arm pain VAS scores, and NDI scores did not significantly differ between the BGC and allograft groups. CONCLUSIONS: CaO-SiO2-P2O5-B2O3 BGC cage was effective and safe when used in ACDF, conferring a high fusion rate and favorable clinical outcomes similar to those of the allograft.

How Does Ossification of Posterior Longitudinal Ligament Progress in Conservatively Managed Patients?

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The aim of this study was to elucidate the progression of ossification of the posterior longitudinal ligament (OPLL) in conservatively managed patients and determine its risk factors SUMMARY OF BACKGROUND DATA.: Although several studies have demonstrated how OPLL progresses after laminoplasty or fusion, its progression in conservatively managed patients remains unclear. METHODS: The vertical length of the ossified mass and its thickness at each segment were evaluated on sagittal computed tomography images. Patients with vertical growth >2 mm were included in the vertical progression group. Segments with a thickness progression >1 mm were classified as thickness progressed segments, and patients who had at least one progressed segment were included in the thickness progression group. Based on the characteristics at each disc level, the ossified mass at each segment was classified into four types: type 1, no disc space involvement; type 2, involving the disc space, but not crossing; type 3, crossing the disc space, but not fused; and type 4, completely fused. RESULTS: The progression of ossified mass was observed in younger patients (P < 0.01) and in C2-C3 involvement (P < 0.01) cases. Moreover, progression in both directions was observed more frequently in the mixed-type OPLL (P < 0.01). Progression occurred most often in type 3 segments (72.0%, P < 0.01). In type 3 segments, thickness progression was found more frequently in segments with segmental range of motion (ROM) ≥5° (55.6% vs. 27.8%, P = 0.04). The proportion of segments whose initial thickness was >5 mm was significantly higher among progressed segments (60.0% vs. 35.2%, P = 0.03). CONCLUSION: Young age, C2-C3 involvement, and mixed-type OPLL are risk factors for OPLL progression. Segments with morphology of crossing the segment, but without fusion (type 3), segmental ROM ≥5°, and initial thickness >5 mm need special attention. LEVEL OF EVIDENCE: 3.

Conservative Management after Intraoperative Over-Release of the Medial Collateral Ligament from its Tibial Insertion Site in Patients Undergoing Total Knee Arthroplasty.

During varus deformity correction in a patient undergoing total knee arthroplasty (TKA), the medial collateral ligament (MCL) could get completely detached from its distal insertion site. Our aim was to evaluate the (1) mid-term clinical outcome and implant survival after conservative treatment in patients with intraoperatively over-released MCL and (2) preoperative risk factors for MCL over-release. A retrospective study was conducted on patients who had undergone a primary TKA between 2001 and 2006. The number of knees with intraoperative MCL over-release (over-released group) was 47 (40 patients); we compared these with the knees that had intact MCL (intact group, 502 knees). Simple anchoring of MCL was performed with no additional protection. The postoperative clinical outcome and implant survival were compared. Risk factors for MCL over-release were identified using multivariate analysis. The average follow-up period was 7.5 years. The mean Knee Society score of the over-released group improved from 23.3 to 92.7 and it was not significantly different from the intact group. Three cases of aseptic loosening occurred in the over-released group and 19 in the intact group (p = 0.423). The survival rates of the implant were 94.4% and 96.1%, respectively, at 13 years postoperatively. Multivariate analysis showed preoperative femoral-tibial angle as the only risk factor for over-release. This study showed that even MCL was over-released inadvertently, but it did not affect the clinical outcome. Preoperative femoral-tibial angle was the only predictable risk factor for MCL over-release.

Comparison of Revision Rates Due to Aseptic Loosening between High-Flex and Conventional Knee Prostheses.

PURPOSE: The purpose was to evaluate and compare the revision rate due to aseptic loosening between a high-flex prosthesis and a conventional prosthesis. MATERIALS AND METHODS: Two thousand seventy-eight knees (1,377 patients) with at least 2 years of follow-up after total knee arthroplasty were reviewed. Two types of implants were selected (LPS-Flex and LPS, Zimmer) to compare revision and survival rates and sites of loosened prosthesis component. RESULTS: The revision rate of the LPS-Flex (4.9%) was significantly higher than that of the conventional prosthesis (0.6%) (p＜0.001). The 5-, 10-, and 15-year survival rates were 98.9%, 96.2% and 92.0%, respectively, for the LPS-Flex and 99.8%, 98.5% and 93.5%, respectively, for the LPS. The survival rate of the high-flex prosthesis was significantly lower than that of the conventional prosthesis, especially in the mid-term period (range, 5 to 10 years; p=0.002). The loosening rate of the femoral component was significantly higher in the LPS-Flex prosthesis (p=0.001). CONCLUSIONS: The LPS-Flex had a higher revision rate due to aseptic loosening than the LPS prosthesis in the large population series with a long follow-up. The LPS-Flex should be used carefully considering the risk of femoral component aseptic loosening in the mid-term (range, 5 to 10 years) follow-up period after initial operation.

Nonweightbearing Radiographs in Patients With a Subtle Lisfranc Injury.

BACKGROUND: A midfoot sprain can be easily missed because of minimal findings on initial radiographs, which are almost universally nonweightbearing. We investigated preoperative nonweightbearing plain radiographic images in patients who were found to have unstable subtle Lisfranc injuries. METHODS: We retrospectively reviewed 51 patients who were operated on between February 2004 and March 2015. Abnormal preoperative radiographic findings and intraoperative instability were compared. The relationship was calculated with Fisher's exact test. RESULTS: Based on intraoperative findings, medial cuneiform (C1)-second metatarsal (M2) instability was observed in 50 cases (98%), which was the most common. Thirty-nine cases (76.4 %) had multiple joint (at least 2) instability. In the preoperative radiologic findings, C1-M2 diastasis was the most common abnormal finding, in 46 cases (90.1%). Specificity and positive predictive value were 1.0 in C1-M2 avulsion, diastasis, and C1-intermediate cuneiform (C2) diastasis. Abnormal findings of C1-C2, C1-M1, and C2-M2 showed a significant relationship with intraoperative instability ( P < .05). CONCLUSION: C1-M2 avulsion and diastasis and C1-C2 diastasis were definite preoperative predictors of instability. In unstable subtle Lisfranc injuries, 90% had at least a minor radiographic abnormality at the C1-M2 joint on nonweightbearing radiographs. However, caution should be exercised to identify instability without radiographic abnormality in the C1-M2 joint. LEVEL OF EVIDENCE: Level IV, retrospective case series.