Natasa Miljkovic

Adipose-derived stem cells for wound healing applications.

Nonhealing wounds remain a significant challenge for plastic surgeons. More than 600,000 people suffer from venous ulcers and 1.5 to 3 million people are being treated for pressure sores every year in the United States. The use of tissue engineering techniques such as stem-cell therapy and gene therapy to improve wound healing is a promising strategy. Adipose tissue represents a source of cells that may be able to enhance wound healing. Adipose-derived stem cells (ASCs) are adult stem cells that are easily harvested and of great interest for plastic surgeons. Specifically, ASCs secrete angiogenic growth factors that can induce tissue regeneration. This review describes innovative research strategies using ASCs therapies for treatment of chronic, nonhealing wounds.

Chondrogenesis, bone morphogenetic protein-4 and mesenchymal stem cells

OBJECTIVE As adult cartilage has very limited potential to regenerate, cartilage repair is challenging. Available treatments have several disadvantages, including formation of fibrocartilage instead of hyaline-like cartilage, as well as eventual ossification of the newly formed tissue. The focus of this review is the application of bone morphogenetic protein-4 (BMP-4) and mesenchymal stem cells (MSCs) in cartilage repair, a combination that could potentially lead to the formation of permanent hyaline-like cartilage in the defect. METHODS This review is based on recent literature in the orthopaedic and tissue engineering fields, and is focused on MCSs and bone morphogenetic proteins (BMPs). RESULTS BMP-4, a stimulator of chondrogenesis, both in vitro and in vivo, is a potential therapeutic agent for cartilage regeneration. BMP-4 delivery can improve the healing process of an articular cartilage defect by stimulating the synthesis of the cartilage matrix constituents: type II collagen and aggrecan. BMP-4 has also been shown to suppress chondrogenic hypertrophy and maintain regenerated cartilage. Use of an appropriate carrier for BMP-4 is crucial for successful reconstruction of cartilage defects. Due to the relatively short half-life in vivo of BMP-4, there is a need to localize and maintain the delivery of BMP-4 to the injury site. Additionally, the delivery of MSCs to the wound site could improve cartilage regeneration; therefore, the carrier should function both as a cell and a protein delivery vehicle. CONCLUSION The role of BMP-4 in chondrogenesis is significant, and successful methods to deliver BMP-4, with or without MSCs, to the cartilage defect site are a promising therapy to treat cartilage defects.

Calcium Aluminate, RGD-Modified Calcium Aluminate, and β-Tricalcium Phosphate Implants in a Calvarial Defect

Calcium aluminate (CaAl), arginine-glycine-aspartic acid-modified CaAl, and &bgr;-tricalcium phosphate (TCP) implants were studied in a rat calvarial critical-sized defect model. The rates of newly formed bone and osteointegration were measured using 3 different methods: radiography, micro-computed tomography, and histologic examination. After 4 weeks, there was no new bone formed and no signs of osteointegration into the skull bone in the CaAl or arginine-glycine-aspartic acid-modified CaAl groups, and thick fibrous capsules were visible around the whole circumference of the implants in both groups. In the &bgr;-TCP group, neovascularization of the implant was observed, which is consistent with the early phase of new bone formation. In addition, in the &bgr;-TCP group, signs of implant integration into the host tissue were evident at 4 weeks. There was no soft tissue reaction around the &bgr;-TCP implant. These observations suggest that more specific adhesion peptides may be needed to activate the bioinert CaAl implant and promote bone formation in the craniofacial skeleton.

Femoral guide breakage during the anteromedial portal technique used for ACL reconstruction

Positioning of the femoral tunnel is very important in ACL reconstruction and it is often recommended to use an anteromedial portal technique in order to create the tunnel. This technique is more demanding but it gives a surgeon more freedom to place the ACL graft in an anatomical position compared to the transtibial technique. A case of an intraarticular femoral guide breakage associated with this particular technique is presented. That being said, the aim of this paper is not only to present this rare complication following arthroscopic reconstruction of ACL, but also to indicate how to prevent, diagnose and treat this undesired event.

Clinical Experience With Continuous Intrathecal Baclofen Trials Prior to Pump Implantation

To report our clinical experience using continuous intrathecal baclofen (ITB) trials prior to permanent pump implantation.

Broken Ender nails after fixation of concomitant ipsilateral fractures of the femoral neck and shaft.

Concomitant ipsilateral fractures of the upper part and shaft of the femur are uncommon injuries. Because of the small number of cases reported and the diversity of devices used, no single type of internal fixation stands out as the best treatment for both of these fractures. This report describes a case of concomitant ipsilateral fractures of the femoral neck and shaft that is further distinguished by a rare complication: breakage of Ender nails after fixation.

Carpometacarpal Dislocation of the Thumb Associated With Ipsilateral Fracture of the Distal Radius

An acute carpometacarpal (CMC) dislocation of the thumb is itself an extremely rare injury, but one associated with a fracture of the distal radius has never before been reported. In our case, the fracture of the distal radius was treated by closed reduction and immobilization with a plaster cast, whereas the dislocation of the CMC of the thumb was treated with closed reduction, percutaneous fixation with Kirschner wires, and immobilization with a plaster cast. At the patients two-year follow-up examination, the distal radius fracture displayed successful functional and radiographic results, but a subluxation of the CMC joint was evident.

Bilateral Congenital Posterior Cruciate Ligament Hypoplasia

Congenital aplasia or hypoplasia of the cruciate ligaments is an infrequent condition. The absence of the posterior cruciate ligament (PCL) is extremely rare and is usually associated with other congenital abnormalities of the lower limb such as anterior cruciate ligament (ACL) agenesis, absence of one or both menisci, and absence or dysplasia of the patella1-7. To the best of our knowledge, only one case of a unilateral PCL absence8 and one case of bilateral PCL hypoplasia9 have been reported in the literature. We present the case of a professional athlete with bilateral congenital PCL hypoplasia without other associated congenital anomalies. The patient was informed that data concerning the case would be submitted for publication, and she provided consent. A twenty-nine-year-old female professional athlete, who had played handball from the age of twelve years and had competed in the premier league from the age of sixteen years, sustained a twisting injury to the right knee while landing. Seven days later, examination revealed a minimal right knee effusion and a positive Lachman test with a soft end point. The posterior drawer sign had a hard stop, and the posterior sag sign was negative. No lateral or medial instability was observed. Active and passive knee motion was intact. The patient denied any family history of skeletal congenital abnormalities; no abnormalities had been noted during pregnancy, childbirth, or childhood. Five years prior to this event, she had given birth to a healthy girl who had normal physical and mental development. Magnetic resonance imaging (MRI) of the right knee (Figs. 1-A, 1-B, and 1-C) demonstrated a recent ACL tear with a fully disorganized and partially retracted ligament as well as associated intra/periligamentous edema. The PCL did not have a normal appearance; there was only a thin, hypointense bandlike structure, …

Hybrid hamstring graft tibial fixation in anterior cruciate ligament reconstruction

Tibial fixation of the anterior cruciate ligament hamstring tendon graft is commonly considered more problematic than femoral fixation. When interference screws are used for tibial hamstring tendon graft fixation, graft sometimes looses its tension, so a hybrid fixation (more than one method of fixation) must be applied. Biomechanical studies show that an implementation of interference screws combined with different indirect distal hamstring tendon fixation techniques can withstand much higher tearing forces when compared with one type of fixation. We made a technique of hybrid tibial fixation of the hamstring graft using round interference screws and an additional bi-cortical 4.5-mm diameter screw with a modified head that allows control over the initial tension of the graft.