RESUMO
Surgical fixation of distal femur fractures in geriatric patients is an evolving topic. Unlike hip fractures, treatment strategies for distal femur fractures are ill-defined and lack substantive high-quality evidence. With an increasing incidence and an association with significant morbidity and mortality, it is essential to understand existing treatment options and their supporting evidence. Current fixation methods include the use of either retrograde intramedullary nails, or plate and screw constructs. Due to the variability in fracture patterns, the unique anatomy of the distal femur, and the presence or absence or pre-existing implants, decision-making as to which method to use can be challenging. Recent literature has sought to describe the advantages and disadvantages of each, however, there is currently no consensus on a standard of care, and little randomized evidence is available that directly compares intramedullary nails with plating. Future randomized studies comparing intramedullary nails with plating constructs are necessary in order to develop a standard of care based on injury characteristics.
Assuntos
Fraturas Femorais Distais , Fraturas do Fêmur , Fixação Intramedular de Fraturas , Humanos , Idoso , Pinos Ortopédicos/efeitos adversos , Fixação Interna de Fraturas/efeitos adversos , Fixação Intramedular de Fraturas/efeitos adversos , Parafusos Ósseos/efeitos adversos , Placas Ósseas/efeitos adversos , Fraturas do Fêmur/cirurgia , Fraturas do Fêmur/etiologia , FêmurRESUMO
PURPOSE: Existing literature is discrepant on the differences in blood loss and need for transfusion between short and long cephalomedullary nails used for extracapsular geriatric hip fractures. However, prior studies used the inaccurate estimated rather than the more accurate 'calculated' blood loss based on hematocrit dilution (Gibon in IO 37:735-739, 2013, Mercuriali in CMRO 13:465-478, 1996). This study sought to clarify whether use of short nails is associated with clinically meaningful reductions in calculated blood loss and resultant need for transfusion. METHODS: A retrospective cohort study using bivariate and propensity score-weighted linear regression analyses was conducted examining 1442 geriatric (ages 60-105) patients undergoing cephalomedullary fixation of extracapsular hip fractures over 10 years at two trauma centers. Implant dimensions, pre and postoperative laboratory values, preoperative medications, and comorbidities were recorded. Two groups were compared based on nail length (greater or less than 235 mm). RESULTS: Short nails were associated with a 26% reduction in calculated blood loss (95% confidence interval: 17-35%; p < 10-14) and a 24-min (36%) reduction in mean operative time (95% confidence interval: 21-26 min; p < 10-71). The absolute reduction in transfusion risk was 21% (95% confidence interval: 16-26%; p < 10-13) yielding a number needed to treat of 4.8 (95% confidence interval: 3.9-6.4) with short nails to prevent one transfusion. No difference in reoperation, periprosthetic fracture, or mortality was noted between groups. CONCLUSION: Use of short compared to long cephalomedullary nails for geriatric extracapsular hip fractures confers reduced blood loss, need for transfusion, and operative time without a difference in complications.
Assuntos
Fixação Intramedular de Fraturas , Fraturas do Quadril , Humanos , Idoso , Pinos Ortopédicos , Estudos Retrospectivos , Fixação Intramedular de Fraturas/efeitos adversos , Fixação Intramedular de Fraturas/métodos , Fraturas do Quadril/cirurgia , Parafusos Ósseos , HemorragiaRESUMO
PURPOSE: The objective of this study was to determine the underlying factors that drive the decision for surgeons to pursue operative versus nonoperative management for proximal humerus fractures (PHF) and if fellowship training had an impact on these decisions. METHODS: An electronic survey was distributed to members of the Orthopaedic Trauma Association and the American Shoulder and Elbow Surgeons Society to assess differences in patient selection for operative versus nonoperative management of PHF. Descriptive statistics were reported for all respondents. RESULTS: A total of 250 fellowship trained Orthopaedic Surgeons responded to the online survey. A greater proportion of trauma surgeons preferred nonoperative management for displaced PHF fractures in patients over the age of 70. Operative management was preferred for older patients with fracture dislocations (98%), limited humeral head bone subchondral bone (78%), and intraarticular head split (79%). Similar proportions of trauma surgeons and shoulder surgeons cited that acquiring a CT was crucial to distinguish between operative and nonoperative management. CONCLUSION: We found that surgeons base their decisions on when to operate primarily on patient's comorbidities, age, and the amount of fracture displacement when treating younger patients. Further, we found a greater proportion of trauma surgeons elected to proceed with nonoperative management in patients older than the age of 70 years old as compared to shoulder surgeons.
Assuntos
Fraturas do Úmero , Fraturas do Ombro , Cirurgiões , Humanos , Idoso , Fraturas do Ombro/cirurgia , Cabeça do Úmero , Inquéritos e Questionários , Úmero/cirurgia , Resultado do Tratamento , Fixação Interna de FraturasRESUMO
BACKGROUND: Proximal humerus fractures (PHFs) are managed with open reduction and internal fixation (ORIF), hemiarthroplasty (HA), reverse shoulder arthroplasty (RSA), or nonoperatively. Given the mixed results in the literature, the optimal treatment is unclear to surgeons. The purpose of this study was to survey orthopedic shoulder and trauma surgeons to identify the patient- and fracture-related characteristics that influence surgical decision-making. METHODS: We distributed a 23-question closed-response email survey to members of the American Shoulder and Elbow Surgeons and Orthopaedic Trauma Association. Questions posed to respondents included demographics, surgical planning, indications for ORIF and arthroplasty, and the use of surgical augmentation with ORIF. Numerical and multiple-choice responses were compared between shoulder and trauma surgeons using unpaired t-tests and χ2 tests, respectively. RESULTS: Respondents included 172 shoulder and 78 trauma surgeons. When surgery is indicated, most shoulder and trauma surgeons treat 2-part (69%) and 3-part (53%) PHFs with ORIF. Indications for managing PHFs with arthroplasty instead of ORIF include an intra-articular fracture (82%), bone quality (76%), age (72%), and previous rotator cuff dysfunction (70%). In patients older than 50 years, 90% of respondents cited a head-split fracture as an indication for arthroplasty. Both shoulder and trauma surgeons preferred RSA for treating PHFs presenting with a head-split fracture in an elderly patient (94%), pre-existing rotator cuff tear (84%), and pre-existing glenohumeral arthritis with an intact cuff (75%). Similarly, both groups preferred ORIF for PHFs in young patients with a fracture dislocation (94%). In contrast, although most trauma surgeons preferred to manage PHFs in low functioning patients with a significantly displaced fracture or nonreconstructable injury nonoperatively (84% and 86%, respectively), shoulder surgeons preferred either RSA (44% and 46%, respectively) or nonoperative treatment (54% and 49%, respectively) (P < .001). Similarly, although trauma surgeons preferred to manage PHFs in young patients with a head-split fracture or limited humeral head subchondral bone with ORIF (98% and 87%, respectively), shoulder surgeons preferred either ORIF (54% and 62%, respectively) or HA (43% and 34%, respectively) (P < .001). CONCLUSIONS: ORIF and HA are preferred for treating simple PHFs in young patients with good bone quality or fracture dislocations, whereas RSA and nonoperative management are preferred for complex fractures in elderly patients with poor bone quality, rotator cuff dysfunction, or osteoarthritis. The preferred management differed between shoulder and trauma surgeons for half of the common PHF presentations, highlighting the need for future research.
Assuntos
Artroplastia do Ombro , Hemiartroplastia , Fraturas do Ombro , Articulação do Ombro , Cirurgiões , Idoso , Artroplastia do Ombro/métodos , Humanos , Cabeça do Úmero/cirurgia , Ombro/cirurgia , Fraturas do Ombro/cirurgia , Articulação do Ombro/cirurgia , Resultado do TratamentoRESUMO
BACKGROUND: Proximal humerus fractures (PHFs) are common, and their incidence is increasing as the population ages. Despite this, postoperative rehabilitation remains unstandardized and little is known about surgeon preferences. The aim of this study was to assess differences in postoperative rehabilitation preferences and patient education between orthopedic trauma and shoulder surgeons. METHODS: An electronic survey was distributed to members of the Orthopaedic Trauma Association and the American Shoulder and Elbow Surgeons to assess differences in postoperative rehabilitation preferences and patient counseling. Descriptive statistics were reported for all respondents, trauma surgeons, and shoulder surgeons. Chi-square and unpaired 2-sample t tests were used to compare responses. Multinomial regression was used to further elucidate the influence of fellowship training independent of confounding characteristics. RESULTS: A total of 293 surgeons completed the survey, including 172 shoulder and 78 trauma surgeons. A greater proportion of trauma surgeons preferred an immediate weightbearing status after arthroplasty compared to shoulder surgeons (45% vs. 19%, P = .003), but not after open reduction and internal fixation (ORIF) (62% vs. 75%, P = .412). A greater proportion of shoulder surgeons preferred home exercise therapy taught by the physician or using a handout following reverse shoulder arthroplasty (RSA) (21% vs. 2%, P = .009). A greater proportion of trauma surgeons began passive range of motion (ROM) <2 weeks after 2-part fractures (70% vs. 41%, P < .001). Conversely, a greater proportion of shoulder surgeons began passive ROM between 2 and 6 weeks for 2-part (57% vs. 24%, P < .001) and 4-part fractures (65% vs. 43%, P = .020). On multinomial regression analysis, fellowship training in shoulder surgery was associated with preference for a nonweightbearing duration of >12 weeks vs. 6-12 weeks after ORIF. Similarly, fellowship training in shoulder surgery was associated with increased odds of preferring a nonweightbearing duration of <6 weeks vs. no restrictions and >12 weeks vs. 6-12 weeks after arthroplasty. Training in shoulder surgery was associated with greater odds of preferring a nonweightbearing duration prior to beginning passive ROM of 2-6 weeks vs. <2 weeks or >6 weeks for 2-part fractures, but not 4-part fractures. CONCLUSION: Trauma surgeons have a more aggressive approach to rehabilitation following operative PHF repair compared to shoulder surgeons regarding time to weightbearing status and passive ROM. Given the increasing incidence of PHFs and substantial variations in reported treatment outcomes, differences in rehabilitation after PHF treatment should be further evaluated to determine the role it may play in the outcomes of treatment studies.
Assuntos
Fraturas do Ombro , Cirurgiões , Humanos , Úmero/cirurgia , Redução Aberta , Amplitude de Movimento Articular , Ombro , Fraturas do Ombro/cirurgia , Cirurgiões/psicologia , Resultado do TratamentoRESUMO
BACKGROUND: Failure of surgical fixation in orthopaedic fractures occurs at a significantly higher rate in osteoporotic patients due to weakened osteoporotic bone. A therapy to acutely improve the mechanical properties of bone during fracture repair would have profound clinical impact. A previous study has demonstrated an increase in mechanical properties of acellular cortical canine bone after immersion in raloxifene. The goal of this study was to determine if similar treatment yields the same results in cancellous fetal bovine bone and whether this translates into a difference in screw pull-out strength in human cadaveric tissue. METHODS: Cancellous bone from fetal bovine distal femora underwent quasi-static four-point bending tests after being immersed in either raloxifene (20 µM) or phosphate-buffered saline as a control for 7 days (n = 10). Separately, 5 matched pairs of human osteoporotic cadaveric humeral heads underwent the same procedure. Five 3.5 mm unicortical cancellous screws were then inserted at standard surgical fixation locations to a depth of 30 mm and quasi-static screw pull-out tests were performed. RESULTS: In the four-point bending tests, there were no significant differences between the raloxifene and control groups for any of the mechanical properties - including stiffness (p = 0.333) and toughness (p = 0.546). In the screw pull-out tests, the raloxifene soaked samples and control samples had pullout strengths of 122 ± 74.3 N and 89.5 ± 63.8 N, respectively. CONCLUSIONS: Results from this study indicate that cancellous fetal bovine samples did not demonstrate an increase in toughness with raloxifene treatment, which is in contrast to previously published data that studied canine cortical bone. In vivo experiments are likely required to determine whether raloxifene will improve implant fixation.
Assuntos
Imersão , Cloridrato de Raloxifeno , Animais , Fenômenos Biomecânicos , Parafusos Ósseos , Cadáver , Bovinos , Cães , Humanos , Teste de Materiais , Cloridrato de Raloxifeno/farmacologiaRESUMO
INTRODUCTION: Traumatic intercalary defects of the tibia may be effectively managed with the free fibula flap. However, any alteration of limb alignment with residual bony angular deformity of the tibia must be also addressed. We describe the use of the free fibula flap in conjunction with external fixation to allow residual deformity correction and patient mobilization ambulation during healing of the free flap. METHODS: Retrospective medical record review was conducted of patients with segmental tibial defects greater than 7 cm who underwent reconstruction with fibula free flap and simple pin-bar external fixation, followed by conversion to 6-axis computer-assisted multiplanar circular ring external fixation to correct residual bony deformity. Outcomes analyses included free flap complications, return to the operating room, complications associated with the external fixation, bony union, correction of residual deformity, amputation rate, visual analog pain scales, and patient satisfaction. RESULTS: Eight patients (8 tibiae) underwent reconstruction. Mean tibial bone defect was 10.2 cm; all limbs had soft-tissue defects (mean size, 138 cm). Free fibula grafts were harvested as osteocutaneous or osteomyocutaneous flaps (average length, 12 cm). Complications included 1 delayed union and 3 (37.5%) patients readmitted for graft fracture. Ultimately, 100% of patients achieved graft union with satisfactory correction of residual limb deformity. Limb salvage rate was 100%. DISCUSSION: Management of segmental tibial bone loss utilizing initial simple external fixation and microsurgical reconstruction followed by application of computer-assisted circular external fixator may provide a reliable reconstructive protocol for posttraumatic tibial defects with residual bone malalignment.
Assuntos
Retalhos de Tecido Biológico , Procedimentos de Cirurgia Plástica , Fraturas da Tíbia , Fixadores Externos , Fíbula/cirurgia , Fixação de Fratura , Humanos , Estudos Retrospectivos , Tíbia/cirurgia , Fraturas da Tíbia/diagnóstico por imagem , Fraturas da Tíbia/cirurgia , Resultado do TratamentoRESUMO
Chronic inflammatory responses have profound effects on the differentiation and activity of both the bone-forming osteoblasts and bone-resorbing osteoclasts. Importantly, inflammatory bone diseases characterized by clinical osteolysis promote bone resorption and decrease bone formation by uncoupling the process in favor of excess resorption. Notch signaling regulates osteoclast development and thus its manipulation has the potential to suppress resorptive potential. Here, we have utilized a genetic model of Notch inhibition in osteoclasts by expression of dnMAML to prevent formation of transcriptional complex essential for downstream Notch signaling. Using this model and LPS as a tool for experimental inflammatory osteolysis, we have demonstrated that dnMAML-expressing osteoclasts exhibited significantly lower maturation and resorption/functional potential ex vivo using TRAP staining and calcium phosphate coated surfaces. Moreover, we observed that while LPS stimulated the formation of wildtype osteoclasts pre-treated with RANKL, dnMAML expression produced resistance to osteoclast maturation after LPS stimulation. Genetically, Notch-inhibited animals showed a significantly lower TRAP and CTX-1 levels in serum after LPS treatment compared to the control groups in addition to a marked reduction in osteoclast surfaces in calvaria sections. This report provides evidence for modulation of Notch signaling activity to protect against inflammatory osteolysis. Taken together, the findings of this study will help guide the development of Notch signaling-based therapeutic approaches to prevent bone loss.
Assuntos
Lipopolissacarídeos/farmacologia , Osteoclastos/citologia , Osteólise/prevenção & controle , Receptores Notch/deficiência , Transdução de Sinais , Animais , Colágeno Tipo I/sangue , Colágeno Tipo I/deficiência , Feminino , Camundongos , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Osteoclastos/efeitos dos fármacos , Osteoclastos/metabolismo , Peptídeos/sangue , Peptídeos/deficiência , Ligante RANK/farmacologia , Receptores Notch/biossíntese , Receptores Notch/genética , Receptores Notch/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Fosfatase Ácida Resistente a Tartarato/sangue , Fosfatase Ácida Resistente a Tartarato/deficiência , Fosfatase Ácida Resistente a Tartarato/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcrição GênicaRESUMO
BACKGROUND: Hip fractures are common and serious injuries in the geriatric population. Obtaining informed consent for surgery in geriatric patients can be difficult due to the high prevalence of comorbid cognitive impairment. Given that virtually all patients with hip fractures eventually undergo surgery, and given that delays in surgery are associated with increased mortality, we argue that there are select instances in which it may be ethically permissible, and indeed clinically preferable, to initiate surgical treatment in cognitively impaired patients under the doctrine of presumed consent. In this paper, we examine the boundaries of the license granted by presumed consent and use the example of geriatric hip fracture to build an ethical framework for understanding the doctrine of presumed consent. DISCUSSION: The license to act under presumed consent requires three factors: patient incapacity, clinical urgency and clarity on the correct course of action. All three can apply to geriatric hip fracture. The typical patient frequently lacks capacity. Delays in initiating surgical treatment are associated with markedly increased mortality rates. Last, there appears to be consensus that surgery is the preferred treatment. Nonetheless, because there is a window of safe delay during which treating physicians can stabilize the patient, address reversible causes of cognitive impairment and identify surrogate decision makers, presumed consent should be invoked only as a method of last resort. CONCLUSIONS: A medical situation need not be characterized by risk of imminent and certain death for presumed consent to be relevant. Rather, there are two distinct windows that must be considered: the time interval in which action may be delayed without danger, and the time interval needed to obtain a better form of consent. Presumed consent is appropriate only when the latter exceeds the former.
Assuntos
Tomada de Decisões/ética , Ética Médica , Fraturas do Quadril/cirurgia , Consentimento Livre e Esclarecido/ética , Consentimento Presumido/ética , Fatores Etários , Idoso , Teoria Ética , Humanos , Competência Mental , RiscoRESUMO
BACKGROUND: More than a million surgeries are performed annually in the United States for hip or knee arthroplasty or hip fracture stabilization. One-fifth of these patients have blood transfusions during their hospital stay. Increases in transfusion rates have caused concern about increased adverse events from unnecessary transfusions. METHODS: We systematically reviewed randomized trials examining the effect of restrictive vs liberal transfusion thresholds on patients having major orthopedic surgery. Study results were meta-analyzed with a random-effects model and heterogeneity was tested with the I2 statistic. Study risk of bias was assessed using a modified Jadad scale and evidence strength was measured using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) system. RESULTS: A total of 504 published articles were screened, and 15 met inclusion criteria. The articles described 9 randomized trials, most comparing transfusion thresholds of 8 vs 10 g/dL hemoglobin. All involved hip or knee arthroplasty and/or hip fracture patients. Moderate-strength evidence suggested a reduction in need for transfusion (relative risk, 0.53; 95% confidence interval [CI], 0.39-0.71; I2 = 95%) and mean number of units transfused (-0.95 units, 95% CI, -1.48 to -0.41, I2 = 98%). There was a possible reduction in overall infections with more restrictive transfusion thresholds, although the result was not statistically significant (relative risk, 0.71; 95% CI, 0.47-1.06; I2 = 54%). Moderate-strength evidence suggested no differences in other clinical outcomes between the groups. Limitations included incomplete blinding, inconsistency, and imprecision. CONCLUSION: Moderate-strength evidence suggests that restrictive transfusion practices reduce utilization of transfusions and may decrease infections without increasing adverse outcomes in major orthopedic surgery.
Assuntos
Artroplastia de Quadril , Artroplastia do Joelho/efeitos adversos , Transfusão de Eritrócitos , Procedimentos Ortopédicos , Idoso , Transfusão de Sangue , Hemoglobinas , Fraturas do Quadril/etiologia , Humanos , Tempo de Internação , Pessoa de Meia-Idade , Ortopedia , Controle de Qualidade , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
BACKGROUND: Approximately 20% of all geriatric patients who sustain low-energy hip fractures will die within 1 year of the injury, and approximately 3% will die during the initial inpatient hospital stay. Accordingly, the event of a geriatric hip fracture might be an apt prompt for discussing end-of-life care: in light of the risk of death after this injury, the topic of mortality certainly is germane. However, it is not clear to what degree physicians and patients engage in end-of-life planning even when faced with a hospital admission for this potentially life-threatening condition. QUESTIONS/PURPOSES: We assessed the frequency with which end-of-life care discussions were documented among a sample of geriatric patients admitted for hip fracture surgery. METHODS: We studied 150 adult patients, 70 years and older, admitted between September 2008 and July 2012 for the care of an isolated low-energy hip fracture, who did not have documented evidence of end-of-life care planning before the time of admission. For each patient, the medical record was scrutinized to identify documentation of end-of-life care discussions, an order changing "code status," or a progress note memorializing a conversation related to the topic of end-of-life care planning. RESULTS: Of the 150 subjects who had no documented evidence of end-of-life care planning at the time of admission, 17 (11%) had their code status changed during the initial hospitalization for hip fracture, and an additional four patients (3%) had a documented conversation regarding end-of-life care planning without a subsequent change in code status. Accordingly, there were 129 (86%) patients who had no record of any attention to end-of-life care planning during the hospital stay for hip fracture surgery. CONCLUSIONS: Our findings suggest that physicians may be missing a valuable opportunity to help patients and their families be better prepared for potential future health issues. End-of-life care planning respects patient autonomy and enhances the quality of care. Accordingly, we recommend that discussion of goals, expectations, and preferences should be initiated routinely when patients present with a fragility fracture of the hip. LEVEL OF EVIDENCE: Level IV, therapeutic study.
Assuntos
Planejamento Antecipado de Cuidados , Idoso Fragilizado , Fraturas do Quadril/mortalidade , Assistência Terminal , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Envelhecimento , Comunicação , Feminino , Fraturas do Quadril/diagnóstico por imagem , Fraturas do Quadril/terapia , Mortalidade Hospitalar , Hospitalização , Humanos , Masculino , Pennsylvania , Relações Médico-Paciente , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , Resultado do TratamentoRESUMO
BACKGROUND: Performance on visiting rotations during the senior year of medical school is consistently cited by residency program directors as a critical factor in selecting residents. Nevertheless, the frequency with which visiting rotations are undertaken and the associated financial costs they impose have not been systematically examined. METHOD: Under the auspices of the Electronic Residency Application Service, a survey was sent in March 2015 to all U.S. applicants for residency programs in the 2014-15 academic year. Students were asked how many visiting rotations they performed; the estimated cost of performing each rotation; their perception of their educational value and primary motivation for performing them; and the Match outcome of their residency application. RESULTS: The survey was completed by 2817 applicants, yielding a response rate of 11.3 %. 1898 applicants (67.4 %) performed visiting rotations: 647 applicants (30.0 %) performed one; 640 (22.7 %) performed two; 322 (11.4 %) performed three; and 289 (10.3 %) reported four or more. When accounting for potential response bias, the true prevalence of away rotators was estimated to be 58.7 % of all fourth-year medical students (95 % CI 54.0-63.4 %). The mean number of rotations for participating students was 2.1. Most students performed rotations equally as an audition for residency placement and for education, with some of the more competitive subspecialties reporting more of an audition experience. The mean estimated cost for performing a single rotation was $958. Thirty-six percent of applicants reported matching at an institution where they had rotated, either their home institution or one at which a visiting rotation was performed. CONCLUSIONS: Visiting rotations are prevalent, expensive, and only partly educational. As such, these rotations may impede optimal use of the senior year of medical school and limited student financial resources.
Assuntos
Educação de Graduação em Medicina/economia , Educação de Graduação em Medicina/estatística & dados numéricos , Internato e Residência , Seleção de Pessoal , Critérios de Admissão Escolar , Faculdades de Medicina/economia , Estudantes de Medicina , Atitude do Pessoal de Saúde , Competência Clínica , Feminino , Humanos , Masculino , Motivação , Prevalência , Faculdades de Medicina/normas , Estados UnidosRESUMO
The role of Notch signaling in osteoclast differentiation is controversial with conflicting experimental evidence indicating both stimulatory and inhibitory roles. Differences in experimental protocols and in vivo versus in vitro models may explain the discrepancies between studies. In this study, we investigated cell autonomous roles of Notch signaling in osteoclast differentiation and function by altering Notch signaling during osteoclast differentiation using stimulation with immobilized ligands Jagged1 or Delta-like1 or by suppression with γ-secretase inhibitor DAPT or transcriptional inhibitor SAHM1. Stimulation of Notch signaling in committed osteoclast precursors resulted in larger osteoclasts with a greater number of nuclei and resorptive activity whereas suppression resulted in smaller osteoclasts with fewer nuclei and suppressed resorptive activity. Conversely, stimulation of Notch signaling in osteoclast precursors prior to induction of osteoclastogenesis resulted in fewer osteoclasts. Our data support a mechanism of context-specific Notch signaling effects wherein Notch stimulation inhibits commitment to osteoclast differentiation, but enhances the maturation and function of committed precursors.
Assuntos
Reabsorção Óssea/etiologia , Dipeptídeos/farmacologia , Proteínas de Membrana/farmacologia , Osteoclastos/citologia , Receptores Notch/metabolismo , Fatores de Transcrição/antagonistas & inibidores , Animais , Proteínas de Ligação ao Cálcio/farmacologia , Técnicas de Cultura de Células , Diferenciação Celular/efeitos dos fármacos , Proteínas Imobilizadas/farmacologia , Peptídeos e Proteínas de Sinalização Intercelular/farmacologia , Proteína Jagged-1 , Camundongos , Osteoclastos/metabolismo , Proteínas Serrate-Jagged , Transdução de Sinais/efeitos dos fármacosRESUMO
BACKGROUND: We sought to evaluate clinical and biomechanical outcomes of dual mini-fragment plate fixation for clavicle fractures. We hypothesized that this technique would produce an anatomical reduction with good clinical outcomes, be well tolerated by patients, and demonstrate equivalent biomechanics to single plating. METHODS: Dual mini-fragment plating was performed for 17 isolated, displaced midshaft clavicle fractures. Functional outcomes and complications were retrospectively reviewed. A sawbones model compared dual plating biomechanics to a (1) superior 3.5-mm locking reconstruction plate, or (2) antero-inferior 3.5-mm locking reconstruction plate. RESULTS: On biomechanical testing, with anterior loading, dual plating was significantly more rigid than single locked anterior-plating (p = 0.02) but less rigid than single locked superior-plating (p = 0.001). With superior loading, dual plating trended toward higher rigidity versus single locked superior-plating (p = 0.07) but was less rigid than single locked anterior-plating (p = 0.03). No statistically significant differences in axial loading (p = 0.27) or torsion (p = 0.23) were detected. Average patient follow-up was 16.1 months (12-38). Anatomic reduction was achieved and maintained through final healing (average 14.7 weeks). No patient underwent hardware removal. Average 1-year DASH score was 4.0 (completed in 88 %). CONCLUSIONS: Displaced midshaft clavicle fractures can be effectively managed with dual mini-fragment plating. This technique results in high union rates and excellent clinical outcomes. Compared to single plating, dual plating is biomechanically equivalent in axial loading and torsion, yet offers better multi-planar bending stiffness despite the use of smaller plates. This technique may decrease the need for secondary surgery due to implant prominence and may aid in fracture reduction by buttressing butterfly fragments in two planes.
Assuntos
Traumatismos do Braço/cirurgia , Placas Ósseas , Clavícula/lesões , Fixação Interna de Fraturas/métodos , Fraturas Ósseas/cirurgia , Traumatismos do Braço/fisiopatologia , Fenômenos Biomecânicos , Clavícula/cirurgia , Desenho de Equipamento , Feminino , Fraturas Ósseas/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Miniaturização , Estudos RetrospectivosRESUMO
Posttraumatic osteoarthritis (PTOA) occurs after traumatic injury to the joint. It is most common following injuries that disrupt the articular surface or lead to joint instability. The reported risk of PTOA following significant joint trauma is as high as 75%; articular fractures can increase the risk more than 20-fold. Despite recent advances in surgical management, the incidence of PTOA following intra-articular fractures has remained relatively unchanged over the last few decades. Pathogenesis of PTOA after intra-articular fracture is likely multifactorial and may be associated with acute cartilage injury as well as chronic joint overload secondary to instability, incongruity, and malalignment. Additional studies are needed to better elucidate how these factors contribute to the development of PTOA and to develop advanced treatment algorithms that consist of both acute biologic interventions targeted to decrease inflammation and cellular death in response to injury and improved surgical methods to restore stability, congruity, and alignment.