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Inverse melting or disordering, in which the disordered phase forms upon cooling, is known for a few cases in bulk systems under high pressure. We show that inverse disordering also occurs in two dimensions: For a monolayer of 1,4,5,8-naphthalene-tetracarboxylic dianhydride on Ag(111), a completely reversible order-disorder transition appears upon cooling. The transition is driven by strongly anisotropic interactions within the layer versus with the metal substrate. Spectroscopic data reveal changes in the electronic structure of the system corresponding to a strengthening of the interface bonding at low temperatures. We demonstrate that the delicate, temperature-dependent balance between the vertical and lateral forces is the key to understanding this unconventional phase transition.

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Multipotential processed lipoaspirate (PLA) cells extracted from five human infrapatellar fat pads and embedded into fibrin glue nodules, were induced into the chondrogenic phenotype using chondrogenic media. The remaining cells were placed in osteogenic media and were transfected with an adenovirus carrying the cDNA for bone morphogenetic protein-2 (BMP-2). We evaluated the tissue-engineered cartilage and bone using in vitro techniques and by placing cells into the hind legs of five severe combined immunodeficient mice. After six weeks, radiological and histological analysis indicated that the PLA cells induced into the chondrogenic phenotype had the histological appearance of hyaline cartilage. Cells transfected with the BMP-2 gene media produced abundant bone, which was beginning to establish a marrow cavity. Tissue-engineered cartilage and bone from infrapatellar fat pads may prove to be useful for the treatment of osteochondral defects.

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The objectives of this study were to establish baseline Medical Outcomes Study Short Form Health Survey (SF-36) data for Division I collegiate athletes and to determine the effects of injury severity and training time. All participating athletes (N = 562) at a major university were evaluated with the SF-36. Regression analysis was performed to identify predictive factors. When the men without injury were compared with a previously established norm group, there was a significant increase in the role emotional score. In the women without injury there were significant increases in mental component summary, physical function, role emotional, mental health, and vitality scores when compared with the norm group. Serious injury was a predictor of lower scores in all domains, whereas minimal injury was predictive of lower physical component summary, role physical, bodily pain, social function, and general health scores. Increased training time was predictive of higher mental component summary, role physical, vitality, and general health scores. Elite collegiate athletes scored differently from previously established age-matched norms, and injury was a strong predictor of lower scores.

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This is the first case report of an acute bucket-handle tear in an amateur golfer. The injury occurred during the follow-through phase of the golf swing. The rate of incidence of knee injuries in golfers is only 10%. There is a difference in the injury pattern between amateur and professional golfers; amateurs are more likely to sustain injuries related to poor swing technique. Professional golfers, on the other hand, report more injuries related to overuse. Although forces in the knee are relatively minor in this sport, acute injuries can happen when poor technique is used.

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The cyclops lesion is a fibrous nodule with central granulation tissue located anterolateral to the tibial tunnel after intra-articular reconstruction of the anterior cruciate ligament (ACL) that has been shown to be a cause of failure to regain full extension in the early postoperative period. We present the case of a 23-year-old woman who had undergone arthroscopic ACL reconstruction with a patellar tendon autograft 4 years prior to presentation. Following her reconstruction, she regained full range of motion and returned to collegiate cheerleading. At presentation, she complained of a gradual loss of full extension and joint-line pain with terminal extension. On examination, her graft was stable and she lacked 3 degrees of extension. Magnetic resonance imaging documented a 1-cm mass of low signal intensity immediately anterior to the ACL graft within the intercondylar notch. At arthroscopy, a large amount of thick, immobile scar tissue was found immediately anterior to the ACL, consistent with a cyclops lesion. The lesion was debrided and the patient did well postoperatively. Patients who present with delayed-onset loss of extension after ACL reconstruction should undergo careful evaluation including radiographs and magnetic resonance imaging. If a cyclops lesion is diagnosed, arthroscopic resection should be undertaken.

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Injuries to the extensor mechanisms of the fingers can be career-ending in professional athletes if not treated appropriately. We identified 8 professional athletes who underwent 11 direct metacarpophalangeal joint extensor mechanism repairs including centralization of the extensor tendon and sagittal band repair between 1989 and 1994. Success of the operative procedure was determined by the athlete's attainment of full range of motion, return to professional sports, and no need for additional surgical intervention. The metacarpophalangeal joints of the long and little fingers were most commonly involved. The position of the extensor mechanism disruption and the direction of the tendon subluxation varied. Capsular tears were identified in seven joints and none were repaired. At follow-up, each athlete had regained full range of motion and each had returned to professional sport an average of 5 months postoperatively. No patient required additional surgery. In this series, the principal lesion in metacarpophalangeal joint injury was extensor mechanism disruption with a predictable sagittal band tear and either a radial or ulnar subluxation of the central tendon. We recommend centralization of the extensor tendon and sagittal band repair without capsular repair as a treatment of choice for this injury, particularly in the athlete.

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The unique function of the boxer's hand requires persistent, forceful punching in a constantly clenched fist posture, therefore, the metacarpophalangeal joints are continually exposed to blunt trauma and highly vulnerable to injury. This injury is traditionally termed boxer's knuckle. Although a myriad of metacarpophalangeal joint derangement is apt to result from isolated or repetitive blows inflicted and absorbed by the hand, the most serious and disabling type of boxer's knuckle is extensor hood disruption. Based on experience with 27 surgical cases, this article describes characteristic extensor hood pathology and operative techniques that have afforded a consistently favorable outcome.

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