No abstract

The results of this study indicate that an open autologous osteochondral plug graft allows a return to the previous competitive level of throwing by a mean of 7 months postoperatively.

Evolution of CO 2 in Lakes Monoun and Nyos (Cameroon) before and during controlled degassing is described using results of regular monitoring obtained during the last 21 years. The CO 2(aq) profiles soon after the limnic eruptions were estimated for Lakes Monoun and Nyos using the CTD data obtained in October and November 1986, respectively. Based on the CO 2(aq) profiles through time, the CO 2 content and its change over time were calculated for both lakes. The CO 2 accumulation rate calculated from the pre-degassing data, was constant after the limnic eruption at Lake Nyos (1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001), whereas the rate appeared initially high (1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996) but later slowed down (1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003) at Lake Monoun. The CO 2 concentration at 58 m depth in Lake Monoun in January 2003 was very close to saturation due to the CO 2 accumulation. This situation is suggestive of a mechanism for the limnic eruption , because it may take place spontaneously without receiving an external trigger.The CO 2 content of the lakes decreased significantly after controlled degassing started in March 2001 at Lake Nyos and in February 2003 at Lake Monoun. The current content is lower than the content estimated soon after the limnic eruption at both lakes. At Monoun the degassing rate increased greatly after February 2006 due to an increase of the number of degassing pipes and deepening of the pipe intake depth. The current CO 2 content is ~40% of the maximum content attained just before the degassing started. At current degassing rates the lower chemocline will subside to the degassing pipe intake depth of 93 m in about one year. After this depth is reached, the gas removal rate will progressively decline because water of lower CO 2(aq) concentration will be tapped by the pipes. To keep the CO 2 content of Lake Monoun as small as possible, it is recommended to set up a new, simple device that sends deep water to the surface since natural recharge of CO 2 will continue.Controlled degassing at Lake Nyos since 2001 has also reduced the CO 2 content. It is currently slightly below the level estimated after the limnic eruption in 1986. However, the current CO 2 content still amounts to 80% of the maximum level of 14.8 giga moles observed in January 2001. The depth of the lower chemocline may reach the pipe intake depth of 203 m within a few years. After this situation is reached the degassing rate with the current system will progressively decline, and it would take decades to remove the majority of dissolved gases even if the degassing system keeps working continuously. Additional degassing pipes must be installed to speed up gas removal from Lake Nyos in order to make the area safer for local populations.

Level III, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

Osteochondritis dissecans (OCD) of the humeral capitellum is a critical elbow injury in adolescent overhead throwing athletes. However, its etiology remains unknown. Medical examinations using ultrasonography found that the prevalence of capitellar OCD among adolescent baseball players was approximately from 1% to 3%. A plain anteroposterior radiograph with the elbow in 45° of flexion is essential for the diagnosis of an OCD lesion. The stability of OCD lesions is evaluated on plain radiographs, computed tomography, and magnetic resonance imaging (MRI). Imaging features of the unstable lesions are an epiphyseal closure of the capitellum or a lateral epicondyle, a displaced fragment, or irregular contours of the articular surface and a high signal interface on T2-weighted MRI. A stable lesion has the potential to be healed with conservative treatment. By contrast, surgical treatment should be considered if there is no radiographic improvement within 3 months. In addition, surgery should be performed for the lesions that cause pain during daily activities, have a locking phenomenon, or which are assessed by imaging as obviously unstable. Arthroscopic debridement/loose body removal can be performed for small lesions (≤12 mm in diameter). For large lesions (>12 mm), preservation and/or reconstruction of the articular surface should be selected, such as bone-peg fixation of the lateral part of the fragment and osteochondral autograft transplantation (OAT) from the knee. In the future directions, there is no comparative study of OAT from the knee and rib. In addition, little is known about its long-term outcome, or resulting osteoarthritis. A recent meta-analysis showed that grafts harvested from the knee may lead to donor site morbidity (7.8%). Thus, a novel cartilage tissue engineering approach is anticipated.