Change of Chondral Lesions and Predictive Factors After Medial Open-Wedge High Tibial Osteotomy With a Locked Plate System.

BACKGROUND: Although cartilage regeneration after medial open-wedge high tibial osteotomy (HTO) has been described, there is a paucity of reports regarding which factors influence cartilage regeneration. PURPOSE: To document whether cartilage regeneration occurs in the previously degenerated medial compartment of arthritic knees after medial open-wedge HTO without concomitant cartilage procedures and to assess which predictive factors influence regeneration after HTO. STUDY DESIGN: Case series; Level of evidence, 4 Methods: From February 2008 to January 2014, 104 consecutive knees were enrolled retrospectively that received medial open-wedge HTO with a medial locked plate system without any additional cartilage regeneration procedures and were followed by second-look arthroscopy for plate removal 2 years after surgery. The mean ± SD age at the time of index HTO was 56.3 ± 5.4 years. Cartilage status was graded at the time of initial HTO and second-look arthroscopy according to the International Cartilage Repair Society grading system, and regenerated articular cartilage was classified by the macroscopic staging system of Koshino et al at the time of second-look arthroscopy. Variables evaluated for possible association with regeneration of articular cartilage included age, sex, body mass index (BMI), American Knee Society score, mechanical tibiofemoral angle, medial proximal tibial angle, amount of correction angle, and degree of arthritis. RESULTS: Per the International Cartilage Repair Society grading system, the lesions in the medial femoral condyle and the medial tibial plateau were improved in 54 knees (51.9%) and 36 knees (34.6%), respectively, at the time of second-look arthroscopy. According to the macroscopic grading system, partial and total regeneration of articular cartilage in the medial femoral condyle and the medial tibial plateau was observed in 75 knees (72%) and 57 knees (55%), respectively. Based on univariable logistic regression tests, regeneration of articular cartilage was associated with a smaller mean preoperative varus mechanical tibiofemoral angle (odds ratio [OR], 0.7; P = .023) and lower BMI (OR, 0.8; P = .026) for the medial femoral condyle and younger age (OR, 0.9; P = .048) and a larger mean correction angle (OR, 1.1; P = .023) for the medial tibial plateau. The mean preoperative knee and function scores were significantly improved at the last follow-up, but no correlation was found between the clinical outcomes and cartilage regeneration. Multiple logistic regression analysis for regeneration of articular cartilage showed lower BMI (OR, 0.7; P = .015) to be a significant predictor for the medial femoral condyle. CONCLUSION: Regeneration of degenerated articular cartilage in the medial compartment can be expected while correcting a varus deformity in arthritic knees after medial open-wedge HTO with a locked plate system without any additional cartilage regeneration procedures. Moreover, we suggest that medial open-wedge HTO in the medial arthritic knee with varus malalignment should be highly successful in terms of cartilage regeneration, especially for lower BMI patients.

Are Korean Patients Different from Other Ethnic Groups in Total Knee Arthroplasty?

Most of the implants used for total knee arthroplasty (TKA) in Asian patients have been produced based on anthropometry of Western people. Since anatomic features and life styles are different between Western and Eastern people, there would be ethnic differences in terms of conformity of implants to the patient's anatomy or clinical results after TKA. Therefore, surgeons in Asia are particularly interested in related surgical techniques and implant designs used in TKA for improved clinical results and patient satisfaction. In this review, we investigated the anthropometric differences of Koreans from Westerners. Koreans are of shorter stature, less weight, and smaller skeletal structure and have a higher incidence of constitutional varus alignment of the lower extremity. Moreover, compared to Westerner TKA populations, the proportion of female patients was large and primary osteoarthritis was prevalent in preoperative diagnosis in Korean TKA patients. Culturally, Koreans have life styles that demand high flexion positions of the knee such as squatting, kneeling, and cross-legged sitting. Although there were no notable differences in the complication and revision rates following TKA between Westerners and Koreans, the incidence of postoperative deep vein thrombosis and pulmonary thromboembolism was lower in Koreans than Westerners. We hope that further research on implant designs and more interest in TKA will improve outcomes in Korean patients.

Arthroscopic repair of bucket-handle tears of the lateral meniscus.

PURPOSE: This study was undertaken to document the clinical results of arthroscopic meniscus repair for treatment of displaced bucket-handle tears of the lateral meniscus. METHODS: From 2002 to 2010, 13 patients with symptomatic displaced bucket-handle tears of the lateral meniscus treated by arthroscopic meniscus repair were included in this study. Inclusion criteria were (1) displaced bucket-handle tear of the lateral meniscus demonstrated on magnetic resonance imaging, (2) non-discoid lateral meniscus, (3) stable knee, and (4) tears involving the red-white or red-red zone. Median age at operation was 20 years (range 14-54 years), and the median follow-up period was 4.0 years (range 2-10.7 years). All tears were repaired with either a modified all-inside suture technique only or a combination of the modified all-inside suture and modified outside-in techniques. Clinical results were evaluated preoperatively and at the final follow-up using Tegner activity level, Lysholm knee, and Hospital for Special Surgery (HSS) scores. RESULTS: All patients returned to their prior life activities with little or no limitations, and no reoperations were required during the follow-up period. On the final follow-up, all knees achieved full range of motion, except two knees with limited function during squatting and jumping due to pain. No patient had recurrence of a knee-locking episode. The median Tegner activity level improved significantly from 3 (2-6) to 7 (4-9) (p < 0.0001), mean Lysholm knee score improved from 78.5 ± 10.7 preoperatively to 94.6 ± 5.4 (p < 0.0001), and mean preoperative HSS score improved from 80.3 ± 8.5 to 95.9 ± 4.2 (p < 0.0001) during the follow-up period. CONCLUSION: Arthroscopic meniscus repair using the modified all-inside suture and modified outside-in techniques showed excellent clinical outcomes for treatment of symptomatic displaced bucket-handle tears of the lateral meniscus and were free of any complications or episodes of recurrence. LEVEL OF EVIDENCE: Case series, Level IV.

COMP-Ang1, a variant of angiopoietin 1, inhibits serum-deprived apoptosis of mesenchymal cells via PI3K/Akt and mitogen-activated protein kinase pathways.

BACKGROUND/AIMS: Cartilage oligomeric matrix protein (COMP)-angiopoietin 1 (Ang1) is a soluble and stable form of Ang1 which plays important roles in vessel formation and the survival of endothelial cells, neurons and cardiomyocytes. However, the effects of COMP-Ang1 on the survival of mesenchymal cells are unknown. Mesenchymal cells have been transplanted with some scaffolds for bone tissue regeneration, but they occasionally underwent cell death due to a lack of nutrient supply. This study examined the effects of COMP-Ang1 on the survival of mesenchymal cells under nutrient-deprived conditions. METHODS: Primary and C3H10T1/2 mesenchymal cells were cultured under serum deprivation with or without COMP-Ang1. The effects of COMP-Ang1 on mesenchymal cell survival and its molecular mechanism were determined using a viability test, RT-PCR, Western blotting and fluorescence-activated cell sorting analysis. RESULTS AND CONCLUSION: COMP-Ang1 inhibited the nutrient-deprived apoptotic cell death of mesenchymal cells through the Akt, p38 and extracellular-signal-regulated kinase (ERK) pathways. In addition, COMP-Ang1 reversed the nutrient-deprived suppression of cyclin D1 mRNA expression. These results suggest that COMP-Ang1 has a protective role in the survival of nutrient-deprived mesenchymal cells. The use of COMP-Ang1 with some scaffolds might be useful for bone tissue engineering.

Discoidin domain receptor 1 mediates collagen-induced inflammatory activation of microglia in culture.

Discoidin domain receptor 1 (DDR1) is a nonintegrin collagen receptor tyrosine kinase with an extracellular domain homologous to discoidin 1 of a soil-living amoeba Dictyostelium discoideum. We have previously demonstrated that DDR1 mediates collagen-induced nitric oxide production in J774A.1 murine macrophages. Because collagen is one of the main components of extracellular matrix in the central nervous system, we hypothesized that collagen also induces inflammatory activation of brain microglia, and DDR1 may mediate collagen-induced microglial activation. Using BV-2 mouse microglial cells and mouse primary microglial cultures, we have demonstrated that (1) collagen induces inflammatory activation of microglia as evidenced by production of nitric oxide, expression of inducible nitric oxide synthase, COX-2, CD40, and matrix metalloproteinase-9; (2) DDR1 is expressed in microglia and is phosphorylated by collagen treatment; and (3) collagen-induced microglial activation is abrogated by DDR1 blockade but not by integrin neutralization. We have further shown that p38 MAPK, c-Jun N-terminal kinase, and nuclear factor-kappa B are involved in the collagen-DDR1-induced microglial activation. Our results suggest that collagen can induce inflammatory activation of brain microglia and that DDR1 mediates this effect of collagen in an integrin-independent manner.

Transcription level of granule-associated phaP and phaR genes and granular morphogenesis of poly-beta-hydroxyalkanoate granules in Ralstonia eutropha.

The transcription levels of the granule-associated phaP and phaR genes in Ralstonia eutropha were regulated through the transformation of the phbC genes from R. eutropha and Alcaligenes latus into the poly-beta-hydroxybutyrate synthase-negative mutant. The granular morphogenesis of short chain length, poly-beta-hydroxyalkanoate (scl-PHA) was closely associated with the mRNA transcription levels of the phaP and phaR genes, especially with the ratio of phaP/phaR genes. The phasin protein encoded by the phaP gene increased the number of granules, while the PhaR protein of the phaR gene enlarged the size of the scl-PHA granules in R. eutropha.

Functional role of granule-associated genes, phaP and phaR, in poly-beta-hydroxybutyrate biosynthesis in recombinant E. coli harboring phbCAB operon.

The expression characteristic of two granule-associated genes, phaP and phaR, in a recombinant E. coli harboring the phbCAB operon was investigated. Polybetamydroxybutyrate (PHB) accumulation increased up from 16% to 57% (w/w) after transformation of the granule-associated genes due to the stabilization of PHB granules rather than by a direct effect on PHB biosynthetic enzymes. The morphology of PHB granules also varied depending on the transformed phaP and phaR genes.