Granke M.,Vanderbilt University |
Does M.D.,Vanderbilt University |
Nyman J.S.,Vanderbilt University |
Nyman J.S.,Vanderbilt Orthopaedic Institute
Calcified Tissue International | Year: 2015
Comprising ~20 % of the volume, water is a key determinant of the mechanical behavior of cortical bone. It essentially exists in two general compartments: within pores and bound to the matrix. The amount of pore water—residing in the vascular-lacunar-canalicular space—primarily reflects intracortical porosity (i.e., open spaces within the matrix largely due to Haversian canals and resorption sites) and as such is inversely proportional to most mechanical properties of bone. Movement of water according to pressure gradients generated during dynamic loading likely confers hydraulic stiffening to the bone as well. Nonetheless, bound water is a primary contributor to the mechanical behavior of bone in that it is responsible for giving collagen the ability to confer ductility or plasticity to bone (i.e., allows deformation to continue once permanent damage begins to form in the matrix) and decreases with age along with fracture resistance. Thus, dehydration by air-drying or by solvents with less hydrogen bonding capacity causes bone to become brittle, but interestingly, it also increases stiffness and strength across the hierarchical levels of organization. Despite the importance of matrix hydration to fracture resistance, little is known about why bound water decreases with age in hydrated human bone. Using 1H nuclear magnetic resonance (NMR), both bound and pore water concentrations in bone can be measured ex vivo because the proton relaxation times differ between the two water compartments, giving rise to two distinct signals. There are also emerging techniques to measure bound and pore water in vivo with magnetic resonance imaging (MRI). The NMR/MRI-derived bound water concentration is positively correlated with both the strength and toughness of hydrated bone and may become a useful clinical marker of fracture risk. © 2015, Springer Science+Business Media New York (outside the USA).
Kerkhoffs G.M.M.J.,University of Amsterdam |
Servien E.,Center Albert Trillat |
Dunn W.,Vanderbilt Orthopaedic Institute |
Dahm D.,Mayo Medical School |
And 2 more authors.
Journal of Bone and Joint Surgery - Series A | Year: 2012
Background: The increase in the number of individuals with an unhealthily high body weight is particularly relevant in the United States. Obesity (body mass index ≥30 kg/m2) is a well-documented risk factor for the development of osteoarthritis. Furthermore, an increased prevalence of total knee arthroplasty in obese individuals has been observed in the last decades. The primary aim of this systematic literature review was to determine whether obesity has a negative influence on outcome after primary total knee arthroplasty. Methods: A search of the literature was performed, and studies comparing the outcome of total knee arthroplasty in different weight groups were included. The methodology of the included studies was scored according to the Cochrane guidelines. Data extraction and pooling were performed. The weighted mean difference for continuous data and the weighted odds ratio for dichotomous variables were calculated. Heterogeneity was calculated with use of the I 2 statistic. Results: After consensus was reached, twenty studies were included in the data analysis. The presence of any infection was reported in fourteen studies including 15,276 patients (I2, 26%). Overall, infection occurred more often in obese patients, with an odds ratio of 1.90 (95% confidence interval [CI], 1.46 to 2.47). Deep infection requiring surgical debridement was reported in nine studies including 5061 patients (I2, 0%). Deep infection occurred more often in obese patients, with an odds ratio of 2.38 (95% CI, 1.28 to 4.55). Revision of the total knee arthroplasty, defined as exchange or removal of the components for any reason, was documented in eleven studies including 12,101 patients (I2, 25%). Revision for any reason occurred more often in obese patients, with an odds ratio of 1.30 (95% CI, 1.02 to 1.67). Conclusions: Obesity had a negative influence on outcome after total knee arthroplasty. Level of Evidence: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence. Copyright © 2012 by The Journal of Bone and Joint Surgery, Incorporated.
Birman M.V.,Columbia University |
Lee D.H.,Vanderbilt Orthopaedic Institute
Journal of the American Academy of Orthopaedic Surgeons | Year: 2012
Factitious disorders of the upper extremity can manifest in many different forms; therefore, it is critical to recognize warning signs in the history and examination indicating that the patient may be creating the symptoms and physical manifestations of the presenting illness. These disorders present in such predictable patterns as lymphedema, Secretan syndrome, ulcerations and wound manipulation, clenched fist, subcutaneous emphysema, pachydermodactyly, nail deformities, and self-mutilation. Management recommendations include assigning therapeutic responsibility to one person and the involvement of a multidisciplinary team. Thorough documentation is essential for the protection of both the patient and the treating physician. Treatment of patients with factitious disorders of the upper extremity requires patience and insight to avoid being manipulated into performing unnecessary surgical procedures.
Lee D.H.,Vanderbilt Orthopaedic Institute
Hand Clinics | Year: 2011
This article provides an overview of the current state of linked total elbow arthroplasty. Discussed are the general indications for using a linked implant and currently available implants. Disease-specific indications, contraindications, surgical technique, and rehabilitation are discussed. The overall results and disease-specific results, as well as complications after a linked elbow arthroplasty, are reviewed. © 2011 Elsevier Inc.
Richards J.E.,Vanderbilt Orthopaedic Institute
Orthopedics | Year: 2012
Tibia plafond fractures have historically demonstrated high complication rates. The purpose of this study was to assess the outcomes of tibia plafond fractures following treatment with definitive external fixation vs delayed open reduction and internal fixation (ORIF). Sixty patients were enrolled in a prospective cohort trial at 1 Level I trauma center. No differences were noted between the 2 treatment groups in terms of age, smoking history, presence of comorbidities, mechanism of injury, incidence of open fractures, or Orthopaedic Trauma Association fracture classification. Complete 12-month follow-up was available for 18 patients in the definitive external fixation group and 27 patients in the ORIF group. No difference was noted in articular reduction between the groups at 6 and 12 months postoperatively. Delayed union or non-union occurred in 4 (22.2%) of 18 patients in the external fixation group and 1 (3.7%) of 27 patients in the ORIF group (P=.05). Deep infection was equally likely in either group (P=.33). The ORIF group had improved Iowa Ankle Scores at 6 (23.6 ± 12.1 vs 11.1 ± 7.7; P<.05) and 12 months (5.5 ± 2.2 vs 3.1 ± 1.7; P<.05) postopertively and improved Short Form-36 Physical Function scores at 6 months (49.7 ± 30.1 vs 25.5 ± 8.0; P<.05) postoperatively compared with the external fixation group.External fixation and ORIF can attain bony union with adequate articular reduction and similar infection rates. Patients treated with ORIF appeared to have improved union rates and early outcomes with ankle function and Short Form-36 Physical Function scores. Copyright 2012, SLACK Incorporated.