Health hot news

A research team led by investigators at the Virginia Tech Carilion Research Institute has demonstrated the first rapid measurements of dopamine release in a human brain and provided preliminary evidence that the neurotransmitter can be tracked in its movement between brain cells while a subject expresses decision-making behavior…

Cell cultures form the basis of day-to-day research work in applications that range from the development of drugs and vaccines to the decoding of functions of individual genes. Up until now, cell cultures have been sown, tended, observed and transferred to vessels - all by hand. A new device automates these worksteps completely. The human genome has been decoded…

A team of computer scientists, physicists, and physicians at Harvard have developed a simple yet powerful method of visualizing human arteries that may result in more accurate diagnoses of atherosclerosis and heart disease. The prototype tool, called “HemoVis,” creates a 2D diagram of arteries that performs better than the traditional 3D, rainbow-colored model…

Background: Surgical anterior cruciate ligament reconstruction using tendon grafts has become the standard to treat the functionally unstable anterior cruciate ligament–deficient knee. Although tendons clearly differ biologically from ligaments, multiple animal studies have shown that the implanted tendons indeed seem to remodel into a ligamentous “anterior cruciate ligament–like” structure.

Purpose: The goal of this study was to systematically review the current literature on the “ligamentization” process in human anterior cruciate ligament reconstruction.

Study Design: Systematic review.

Methods: A computerized search using relevant search terms was performed in the PubMed, MEDLINE, EMBASE, and Cochrane Library databases, as well as a manual search of reference lists. Searches were limited to studies examining the healing of the intra-articular portion of the tendon graft based on biopsies of this graft obtained from a living human.

Results: Four studies were determined to be appropriate for systematic review, none of them reaching a level of evidence higher than 3. All reports considered autografts. Biopsy specimens were evaluated by light or electron microscopy and analyzed for vascularization, cellular aspects, and appearance of extracellular matrix. All authors universally agreed that the tendon grafts survive in the intra-articular environment. Based on changes observed in the healing grafts with regard to vascularization, cellular aspects, and properties of the extracellular matrix, different chronologic stages in the ligamentization process were discerned.

Conclusion: The key finding of this systematic review is that a free tendon graft replacing a ruptured human anterior cruciate ligament undergoes a series of biologic processes termed “ligamentization.” The graft seems to remain viable at any time during this course. Histologically, the mature grafts may resemble the normal human anterior cruciate ligament, but ultrastructural differences regarding collagen fibril distribution do persist. Different stages of the ligamentization process are described, but no agreement exists on their time frame. Problematic direct transmission of animal data to the human situation, the limited number of reports considering the ligamentization process in humans, and the potential biopsy sampling error attributable to superficial graft biopsies necessitate further human studies on anterior cruciate ligament graft ligamentization.

Background: An avulsion fracture of the proximal fifth metatarsal may result in a symptomatic nonunion and hinder athletic performance. Nonoperative management is often successful in alleviating symptoms. When symptoms persist, surgery can be undertaken to repair the nonunion or excise the avulsed fragment.

Purpose: The excision of the avulsed bone fragment is evaluated in the management of symptomatic nonunions.

Study Design: Case series; Level of evidence, 4.

Methods: Excision of the avulsed fifth metatarsal fragment was performed in 6 male high-performance athletes with symptomatic nonunions. The remaining edge of bone was contoured and smoothed.

Results: All 6 patients experienced an uneventful operation and recovery, returning to competitive play at a mean of 11.7 weeks. Activity-related pain and discomfort abated after the excision and rehabilitation. No surgical complications were noted.

Conclusion: Surgical excision of the avulsed fragment from the proximal fifth metatarsal is a safe and effective alternative intervention when nonoperative methods fail.

Background: Autologous osteochondral transplantation procedures provide hyaline cartilage to the site of cartilage repair. It remains unknown whether these procedures restore native contact mechanics of the ankle joint.

Purpose: This study was undertaken to characterize the regional and local contact mechanics after autologous osteochondral transplantation of the talus.

Study Design: Controlled laboratory study.

Methods: Ten fresh-frozen cadaveric lower limb specimens were used for this study. Specimens were loaded using a 6 degrees of freedom robotic arm with 4.5 N·m of inversion and a 300-N axial compressive load in a neutral plantar/dorsiflexion. An osteochondral defect was created at the centromedial aspect of the talar dome and an autologous osteochondral graft from the ipsilateral knee was subsequently transplanted to the defect site. Regional contact mechanics were analyzed across the talar dome as a function of the defect and repair conditions and compared with those in the intact ankle. Local contact mechanics at the peripheral rim of the defect and at the graft site were also analyzed and compared with the intact condition. A 3-dimensional laser scanning system was used to determine the graft height differences relative to the native talus.

Results: The creation of an osteochondral defect caused a significant decrease in force, mean pressure, and peak pressure on the medial region of the talus (P = .037). Implanting an osteochondral graft restored the force, mean pressure, and peak pressure on the medial region of the talus to intact levels (P = .05). The anterior portion of the graft carried less force, while mean and peak pressures were decreased relative to intact (P = .05). The mean difference in graft height relative to the surrounding host cartilage for the overall population was –0.2 ± 0.3 mm (range, –1.00 to 0.40 mm). Under these conditions, there was no correlation between height and pressure when the graft was sunken, flush, or proud.

Conclusion/Clinical Relevance: Placement of the osteochondral graft in the most congruent position possible partially restored contact mechanics of the ankle joint. Persistent deficits in contact mechanics may be due to additional factors besides graft congruence, including structural differences in the donor cartilage when compared with the native tissue.

Background: Pseudoaneurysm of the anterior tibial artery (ATA) after ankle arthroscopy is an uncommon complication but can cause unexpected consequences. However, its contributing factor is not fully understood.

Hypothesis: Anatomic factors, such as ATA variations and the distance between the ATA and joint capsule, may contribute to the occurrence of pseudoaneurysm.

Study Design: Case series; Level of evidence, 4.

Methods: The magnetic resonance images and medical records of 358 ankle cases were analyzed. According to locations of the ATA in relation to the peroneus tertius (PT) and the extensor digitorum longus (EDL) tendon on axial magnetic resonance imaging, patients were classified as type 1 (safe type), type 2 (increased risk type), or type 3 (high-risk type). In addition, distances between the anterior joint capsule and the ATA were measured to evaluate the thickness of the anterior fat pad, which contains the ATA and anterior compartment tendons.

Results: In 336 cases (93.8%), the ATA was located medial to the EDL (type 1, safe). In 7 cases (2.0%), the ATA was located lateral to the EDL and PT tendon (type 2, increased risk); and in 15 cases (4.2%), the branching artery was observed lateral to the EDL and PT tendon and the ATA was in the normal position (type 3, high risk). The mean distance between the anterior joint capsule and the ATA was 2.3 ± 1.1 mm.

Conclusion: In 22 (6.2%) of the 358 cases, the ATA and its branches were located near the anterolateral ankle portal, which introduces the risk of vascular damage during arthroscopic surgery. Furthermore, the mean distance between the ATA and the joint capsule was only 2.3 ± 1.1 mm, and thus the ATA is very close to the anterior working space of the ankle joint. Careful preoperative evaluation and an intra-articular procedure may reduce the risk of vascular complications attributable to ankle arthroscopy.

Background: The treatment of exercise-related injuries is often a problem, and recurrent injuries are common. Two recent systematic reviews found only one high-quality paper on the treatment of long-standing groin pain. In this randomized clinical trial, a training program including strength training resulted in a return of 79% of the athletes to the previous level of sport without any groin pain. The long-term effect of this exercise program was evaluated.

Hypothesis: The effect of the exercise program for adductor-related groin pain is long lasting.

Study Design: Randomized controlled trial; Level of evidence, 1.

Methods: Forty-seven (80%) of the 59 original participants of the study agreed to participate in this 8- to 12-year follow-up. They were all interviewed and examined using a standardized and reproducible protocol, identical to the one used in the original trial. The investigating physician (P.N.) was not involved in the original study and was unaware of the original treatment allocation.

Results: A significant effect of the active training treatment still existed for the whole group (P = .047) and even more for the subgroup of 39 (83%) soccer players (P = .012). No significant differences were found regarding age, present sports activity, reasons for activity reduction, or time to follow-up.

Conclusion: The beneficial short-term effect of the exercise program used in the primary randomized clinical trial for treating long-standing adductor-related groin pain in athletes was found to be lasting, both for the whole group and even more for the large subgroup of soccer players. This is the first time an exercise treatment for overuse injuries to the musculoskeletal system has been shown to have a long-lasting effect (8-12 years).