In vitro experimental investigation of the forces and torque acting on the scaphoid during light grasp.

The aim of this study was to measure the magnitude and direction of forces and torque within osteotomized scaphoids within cadaveric wrists during grasping movement of the hand. The mechanical contributions of clinically relevant individual wrist-crossing tendon groups were investigated. Wrists of eight forearms were immobilized in the sagittal, transverse, and coronal plane on a fixation device with unhindered axial gliding. The scaphoid was osteotomized and the fragments stabilized using an interlocking nail. The nail served as a sensor for measurement of inter-fragmentary forces orthogonal and torque around the sensor axis. Thus, torque and cantilever forces were measured which originated between the fragments through co-contraction through the activity of wrist-crossing tendons. Grasping movement of the hand induced a mean maximum torque of 0.038 ± 0.051 Nm and a force of 4.01 ± 1.71 N on the scaphoid. The isolated activation of thumb tendons resulted in a torque of 9.9 E-3 ± 7.7 E-3 Nm and a force of 1.42 ± 0.49 N. Despite immobilization of the wrist, grasping movement of the hand caused substantial forces and torque within the osteotomized scaphoid bone in varying directions and severity among different specimens. These factors may contribute to the development of nonunions and malunions in unstable scaphoid fractures through interfragmentary micromotion. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1734-1742, 2016.

Fat grafting and stem cell enhanced fat grafting to the breast under oncological aspects--recommendations for patient selection.

Reconstructive and aesthetic fat grafting has been introduced to the breast level over the last years. The safety of such procedures has so far not been completely clarified. The concept has now been refined to stem cell enhanced fat grafting. However beside the promise of using adult stem cells in terms of tissue rejuvenation and augmentation, scar treatment and reconstruction, the variance of adipose stem cell function--including angiogenetic, antiapoptotic, immunomodulatory, chemotactic and anti-scarring potential--raises new scepsis about oncological safety. Herein we reviewed experimental and clinical data on fat grafting and stem cell enhanced fat grafting addressing surgical promise and oncological concerns. Based on these data we suggest clinical criteria for patient selection undergoing fat grafting for aesthetic or reconstructive reasons based on their individual breast cancer risk.

Management and outcome of periprosthetic fractures after total knee arthroplasty.

BACKGROUND: The incidence of periprosthetic fractures after total knee arthroplasty is continuously rising because of an increasing number of knee joint replacements and an enhanced survivorship of the elderly population after knee arthroplasty. The purpose of this study was to analyze the practicability and effectiveness of the various treatment methods for management of periprosthetic fractures after total knee arthroplasty, and to determine the clinical and radiographic long-term results of patients following surgical and nonoperative treatment of these injuries. METHODS: We reviewed the clinical and radiographic records of 41 patients (31 women and 10 men; average age, 78.6 years) with periprosthetic fractures after total knee arthroplasty between 1992 and 2008. Thirty-seven patients showed a periprosthetic fracture of the distal femur, and four patients had a periprosthetic proximal tibial fracture. Thirty-six patients underwent operative stabilization by plate fixation (n = 18), intramedullary nailing (n = 15) or revision arthroplasty (n = 3), and five patients were treated nonoperatively by long-term cast immobilization. RESULTS: Twenty-eight patients returned to their preinjury activity level and were satisfied with their clinical outcome. In 10 patients, we saw a relevant decrease of knee function and severe limitations in gait and activities of daily living. Three patients died related to surgery. Successful fracture healing within 6 months was achieved in 33 (87%) of 38 patients. Failures of reduction or fixation occurred in 8 (21%) of 38 patients. Reoperation due to technical failures was necessary in three patients. CONCLUSIONS: Compared with current data in literature, we had a satisfactory outcome in following individualized treatment of periprosthetic fractures after knee joint replacement. Referring to the wide field of treatment options and high rates of complications, periprosthetic femoral fractures around the knee commonly constitute a challenging problem for the treating surgeons and require an adequate analysis of fracture etiology and a corresponding transfer into an individual treatment concept.

Plate fixation of odontoid fractures without C1-C2 arthrodesis: practice of a novel surgical technique for stabilization of odontoid fractures, including the opportunity to extend the fixation to C3.

OBJECTIVE: Surgical treatment of odontoid fractures that do not allow interfragmentary fracture compression involves either posterior atlantoaxial arthrodesis or additional anterior stabilization using a plate construct. The purpose of this study was to determine the clinical and radiographic outcome after anterior plate fixation of odontoid fractures that were not suitable for anterior screw fixation. METHODS: We reviewed the clinical and radiographic records of 9 patients with an average age of 54 years at the time of surgery who had undergone anterior plate fixation of an odontoid fracture. Indications for using a plate construct were odontoid fractures with anterior oblique fracture lines, fractures with comminution or major displacement, and pathological fractures. RESULTS: Eight patients returned to their preinjury activity level and were satisfied with their treatment. One patient reported chronic pain symptoms and a notable decrease in cervical spine motion. Using the Smiley-Webster Scale to quantify their clinical outcome, we achieved an overall outcome score of 1.6. Bony fusion was achieved in all patients. Reduction or fixation failed in 2 patients. Reoperation for technical failures was not necessary in any of the patients. CONCLUSION: We had promising results using anterior plate fixation for surgical treatment of odontoid fractures that did not allow interfragmentary fracture compression. Because this method avoids the rigid fixation of the atlantoaxial joint in contrast to techniques of posterior cervical arthrodesis, it seems to be a practical option for the management of fracture types that require additional stabilization of the odontoid.