Localization of vascular endothelial growth factor during the early stages of osteochondral regeneration using a bioabsorbable synthetic polymer scaffold

Vascular endothelial growth factor (VEGF) plays a critical role in chondrogenic differentiation in the growth plate of the epiphysis. This function is necessary for chondrocyte survival in cartilage development. We investigated the localization of VEGF in the osteochondral regeneration process using a bioabsorbable polymer scaffold. Osteochondral defects (5 mm in diameter and 5 mm in depth) were made on the femoral condyle of forty-eight skeletally mature female Japanese white rabbits. In total, twenty-four defects were filled with poly(DL-lactide-co-glycolide) scaffolds and the others were left untreated. The regeneration process was investigated macroscopically, histologically, immunohistochemically, and by gene expression analysis. In the early stages of osteochondral regeneration, bone ingrowth was observed in the deep zone of the scaffold with continuous VEGF expression; cartilage regeneration was observed in the superficial zone of the scaffold with decreased VEGF expression. In contrast, when the defect was left untreated, VEGF localization was observed throughout the entire defect area, and cartilage regeneration at the articular surface was delayed. We conclude that decrease in localization of VEGF at the articular surface in the postoperative early stage is closely related to the progression of cartilage regeneration in osteochondral defects.

MYCOBACTERIAL TUBERCULOUS TENOSYNOVITIS OF THE EXTENSOR TENDON OCCURRING AFTER LIVER TRANSPLANTATION: A CASE REPORT

Mycobacterial tuberculous tenosynovitis of the hand is a rare manifestation of extrapulmonary tuberculosis, while mycobacterial tuberculous tenosynovitis of the extensor tendon sheath is extremely rare. We report a case of tuberculous tenosynovitis of the extensor tendon of the finger, occurring in a man receiving immunosuppression following a liver transplantation. Symptoms improved clinically after conservative treatment with anti-tuberculous drugs.

Potency of double-layered poly L-lactic acid scaffold in tissue engineering of tendon tissue

A successful scaffold for use in tendon tissue engineering requires a high affinity for living organisms and the ability to maintain its mechanical strength until maturation of the regenerated tissue. We compared two types of poly(L-lactic acid) (PLLA) scaffolds for use in tendon regeneration, a plain-woven PLLA fabric (fabric P) with a smooth surface only and a double layered PLLA fabric (fabric D) with a smooth surface on one side and a rough (pile-finished) surface on the other side. These two types of fabric were implanted into the back muscles of rabbits and evaluated at three and six weeks after implantation. Histological examination showed collagen tissues were highly regenerated on the rough surface of fabric D. On the other hand, liner cell attachment was seen in the smooth surface of fabric P and fabric D. The total DNA amount was significantly higher in fabric D. Additionally, mechanical examination showed fabric P had lost its mechanical strength by six weeks after implantation, while the strength of fabric D was maintained. Fabric D had more cell migration on one side and less cell adhesion on the other side and maintained its initial strength. Thus, a novel form of double-layered PLLA fabric has the potential to be used as a scaffold in tendon regeneration.

Treatment of subungual glomus tumor

We report four cases of chronic obscure pain in the finger tips. High-resolution magnetic resonance imaging (HR-MRI) findings helped diagnose the existence of a mass at the subungual area and all patients were treated with excision and biopsy. The pathological diagnosis was glomus tumor. HR-MRI is useful in the diagnosis of patients with subungual glomus tumor.

Stress fracture of the first rib in a high school weight lifter

A 17-year-old boy, who played a weight lifting in high school, sustained stress fracture of the first rib without any causes. We successfully treated first rib stress fracture with limitation of using the upper extremity and with using low-intensity pulsed ultrasound. Key pointsStress fracture of the first rib in a weight lifter was successfully treated with limitation of sports activity and with LIPUS treatment.

Anterosuperior dislocation of the shoulder joint in an older patient with Parkinson's disease

An 83-year-old woman, subsequently diagnosed with Parkinson's disease, fell on her right shoulder. Radiographs showed the humeral head dislocated anterosuperiorly. The supraspinatus tendon was massively disrupted and judged irreparable. The subscapularis tendon was repaired, however re-dislocation of the humeral head was confirmed after the surgery but further treatment was rejected as she was almost pain free and had a low activity level. The patient was followed up for one year after surgery and her shoulder became almost pain-free, but range of motion with active elevation was limited. In such cases a goal of absence or reduction of pain rather than real repair might be considered appropriate.

The effect of porosity and mechanical property of a synthetic polymer scaffold on repair of osteochondral defects

We have made three types of poly (DL-lactide-co-glycolide) (PLG) scaffolds (porosity: scaffold I 80 +/- 0.9%, II 85 +/- 0.8%, III 92 +/- 0.7%; compression module determined with 10% strain: scaffold I 0.26 MPa, II 0.091 MPa, III 0.0047 MPa). Osteochondral defects made in the femoral condyle of rabbits were treated with these scaffolds and the possibilities of cartilage repair were investigated histologically. At post-operative weeks 6 and 12, histological scores in the groups of scaffolds II and III were significantly higher than the score in the group of scaffold I. Scaffolds II and III, which have higher porosity than scaffold I, allow better migration of bone marrow cells and better replacement of the scaffold with bone and cartilage than scaffold I. This study suggests that higher porosity allowing bone marrow cells to migrate to the scaffold is important in repairing osteochondral defects.