Safety Considerations in 3D Bioprinting Using Mesenchymal Stromal Cells.

Three-dimensional (3D) bioprinting has demonstrated great potential for the fabrication of biomimetic human tissues and complex graft materials. This technology utilizes bioinks composed of cellular elements placed within a biomaterial. Mesenchymal stromal cells (MSCs) are an attractive option for cell selection in 3D bioprinting. MSCs can be isolated from a variety of tissues, can pose vast proliferative capacity and can differentiate to multiple committed cell types. Despite their promising properties, the use of MSCs has been associated with several drawbacks. These concerns are related to the ex vivo manipulation throughout the process of 3D bioprinting. The herein manuscript aims to present the current evidence surrounding these events and propose ways to minimize the risks to the patients following widespread expansion of 3D bioprinting in the medical field.

In situ three-dimensional printing for reparative and regenerative therapy.

Three-dimensional (3D) bioprinting is an emerging biofabrication technology, driving many innovations and opening new avenues in regenerative therapeutics. The aim of 3D bioprinting is to fabricate grafts in vitro, which can then be implanted in vivo. However, the tissue culture ex vivo carries safety risks and thereby complicated manufacturing equipment and practice are required for tissues to be implanted in the humans. The implantation of printed tissues also adds complexities due to the difficulty in maintaining the structural integrity of fabricated constructs. To tackle this challenge, the concept of in situ 3D bioprinting has been suggested in which tissues are directly printed at the site of injury or defect. Such approach could be combined with cells freshly isolated from patients to produce custom-made grafts that resemble target tissue and fit precisely to target defects. Moreover, the natural cellular microenvironment in the body can be harnessed for tissue maturation resulting in the tissue regeneration and repair. Here, we discuss literature reports on in situ 3D printing and we describe future directions and challenges for in situ 3D bioprinting. We expect that this novel technology would find great attention in different biomedical fields in near future.

Three Dimensional Printed Bone Implants in the Clinic.

Implants are being continuously developed to achieve personalized therapy. With the advent of 3-dimensional (3D) printing, it is becoming possible to produce customized precisely fitting implants that can be derived from 3D images fed into 3D printers. In addition, it is possible to combine various materials, such as ceramics, to render these constructs osteoconductive or growth factors to make them osteoinductive. Constructs can be seeded with cells to engineer bone tissue. Alternatively, it is possible to load cells into the biomaterial to form so called bioink and print them together to from 3D bioprinted constructs that are characterized by having more homogenous cell distribution in their matrix. To date, 3D printing was applied in the clinic mostly for surgical training and for planning of surgery, with limited use in producing 3D implants for clinical application. Few examples exist so far, which include mostly the 3D printed implants applied in maxillofacial surgery and in orthopedic surgery, which are discussed in this report. Wider clinical application of 3D printing will help the adoption of 3D printers as essential tools in the clinics in future and thus, contribute to realization of personalized medicine.

Gradual reduction of chronic fracture dislocation of the ankle using ilizarov/taylor spatial frame.

With the advances in trauma care, chronic fracture dislocation of the ankle is not a condition commonly seen in modern clinical practice. When encountered, it can be difficult to preserve the ankle joint. We present a case of a 65-year-old female, with a chronic fracture dislocation of the ankle. The ankle joint was subluxated with posterior translation of the talus, displacement of the posterior malleolus fragment, and a distal fibula fracture. A minimally traumatic approach was devised to treat this complex fracture dislocation which included gradual reduction of the ankle with a Taylor spatial frame, followed by stabilization with internal fixation and removal of the frame. Bony union and restoration of the ankle joint congruency was achieved.

Joint preservation of the osteoarthritic ankle using distraction arthroplasty.

BACKGROUND: In recent years ankle distraction arthroplasty has gained popularity in the treatment of ankle arthritis as a means of both maintaining range of motion and avoiding fusion. We present a retrospective review of 25 patients who have undergone ankle distraction from 1999 to 2006. MATERIALS AND METHODS: The mean age was 43 years; 16 were male, and 7 were female. Followup was 30 months after frame removal (range, 12 to 60 months). We were able to obtain followup on 23 of 25 patients. Adjuvant procedures were performed in some cases including Achilles tendon lengthening (5), ankle arthroscopy (4), open arthrotomy (1), and supramalleolar tibial and distal fibular osteotomy to correct distal tibial deformity (6). RESULTS: Twenty-one patients (91%) reported improved pain with those furthest post-op experiencing the best results. The average preoperative AOFAS score was 55 (range, 29 to 82), and the average postoperative score was 74 (range, 47 to 96). The difference between pre- and postoperative scores was significant (p = 0.005). SF-36 scores showed modest improvement in all components. Only two of the patients in the study underwent fusion after ankle distraction. Total ankle motion was maintained in all patients with improvement in the functional arc of motion in five patients who started with mild equinus contractures. CONCLUSION: We feel that ankle distraction offers a promising solution for many people with ankle arthritis.

Humeral lengthening and deformity correction in Ollier's disease: distraction osteogenesis with a multiaxial correction frame.

A case of Ollier's disease with deformity and shortening of the humerus is presented. Lengthening of 9 cm and deformity correction of 50 degrees were accomplished with excellent functional and cosmetic results. Unique features of this case were the use of a multiaxial correction monolateral frame and the formation of normal bone within the region of diseased Ollier's bone.

Lengthening and reconstruction of congenital leg deficiencies for enhanced prosthetic wear.

Congenital limb deficiencies with severe shortening and/or deformity can be difficult to fit with a prosthesis. We report two patients in whom gradual lengthening and deformity correction with the Ilizarov/Taylor spatial frame was used to improve prosthesis fit, comfort, and gait.

Functional outcome after surgical reconstruction of posterior tibial tendon insufficiency in patients under 50 years.

BACKGROUND: Procedures utilized to address the flatfoot in this study included medializing calcaneal osteotomy, posterior tibial tendon reconstruction with flexor digitorum longus tendon transfer, and in patients with more severe deformity, lateral column lengthening. We evaluated patients age 50 and less at the time of surgery, who underwent surgical reconstruction for Stage 2 posterior tibial tendon dysfunction. Pre- and postoperative activity levels were evaluated to assess the effect of surgical reconstruction in the younger patient. MATERIALS AND METHOD: Thirty-four feet in 30 patients (11 male, 19 female) with an average age of 41.2 (range, 17 to 50) years had surgery between 1997 and 2004. All feet were examined at an average followup of 44.5 (range, 24 to 65) months and were evaluated with the American-Orthopaedic-Foot and Ankle Society (AOFAS) Hindfoot-Score and SF-36 score. RESULTS: The average preoperative AOFAS-Score was 53.1 +/- 14.5 points and 83.2 +/- 12.2 points at final postoperative followup. The mean improvement was 29.5. The difference between the preoperative and postoperative AOFAS score was significant (p < 0.0001) using a two-tailed t-test. The difference in the AOFAS pain and alignment subscales was also significant (p < 0.0001). The function subscale improvement was also significant (p = 0.018). The mean physical function component of the postoperative SF-36 score was 79.2. A correlation was found between the SF-36 physical component score and the post operative AOFAS score (r(2) = 0.754). CONCLUSION: While some lateral discomfort or pain occurred in patients with or without a lateral column lengthening, the posterior tibial tendon reconstruction utilizing medial calcaneal displacement osteotomy with flexor digitorum longus transfer and a lateral column lengthening with more deformity was successful in the higher-functioning, younger patients.

Bilateral posterior fracture dislocation of the shoulders following seizure.

Bilateral posterior fracture dislocation is a rare injury known to be associated with seizures. Convulsion was found to be the cause of fracture dislocation in 78% of the cases reported. The mechanism of injury was described by Shaw in 1971. The management depends largely on the severity of the injury. In many cases reported, the fracture was a large compression defect in the anteromedial aspect of the articular surface of the humeral head. It has been suggested that for defects that involve less than 20% of the articular surface closed reduction can be attempted. Rush nail or percutaneous K wires can be used to maintain reduction. Open reduction is necessary for defects that are involving 20-40% of the surface. The aim in these cases is to reconstruct the proximal humerus if possible by the use of internal fixation. If reconstruction is not feasible, a modified McLaughlin procedure can be used to prevent chronic instability of the shoulder. This procedure involves re-implanting the subscapularis tendon into the defect. Reconstructing fractures that involve more than 40% of the articular surface or 4-part fracture is not usually successful. These fractures are associated with a high the risk of avascular necrosis. Hemi-arthroplasty or total shoulder replacement is generally regarded as better option as they offer rapid recovery and eliminate the possibility of multiple procedures if fixation fails.