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BackgroundNonunion is a rare complication of a fracture of the clavicle, but its occurrence can compromise shoulder function. The aim of this study was to evaluate the prevalence of and risk factors for nonunion in a cohort of patients who were treated nonoperatively after a clavicular fracture.MethodsOver a fifty-one-month period, we performed a prospective, observational cohort study of a consecutive series of 868 patients (638 men and 230 women with a median age of 29.5 years; interquartile range, 19.25 to 46.75 years) with a radiographically confirmed fracture of the clavicle, which was treated nonoperatively. Eight patients were excluded from the study, as they received immediate surgery. Patients were evaluated clinically and radiographically at six, twelve, and twenty-four weeks after the injury. There were 581 fractures in the diaphysis, 263 fractures in the lateral fifth of the clavicle, and twenty-four fractures in the medial fifth.ResultsOn survivorship analysis, the overall prevalence of nonunion at twenty-four weeks after the fracture was 6.2%, with 8.3% of the medial end fractures, 4.5% of the diaphyseal fractures, and 11.5% of the lateral end fractures remaining ununited. Following a diaphyseal fracture, the risk of nonunion was significantly increased by advancing age, female gender, displacement of the fracture, and the presence of comminution (p < 0.05 for all). On multivariate analysis, all of these factors remained independently predictive of nonunion, and, in the final model, the risk of nonunion was increased by lack of cortical apposition (relative risk = 0.43; 95% confidence interval = 0.34 to 0.54), female gender (relative risk = 0.70; 95% confidence interval = 0.55 to 0.89), the presence of comminution (relative risk = 0.69; 95% confidence interval = 0.52 to 0.91), and advancing age (relative risk = 0.99; 95% confidence interval = 0.99 to 1.00). Following a lateral end fracture, the risk of nonunion was significantly increased only by advancing age and displacement of the fracture (p < 0.05 for both). On multivariate analysis, both of these factors remained independently predictive of nonunion (p < 0.05), and, in the final model, the risk of nonunion was increased by a lack of cortical apposition (relative risk = 0.38; 95% confidence interval = 0.25 to 0.57) and advancing age (relative risk = 0.98; 95% confidence interval = 0.97 to 0.99).ConclusionsNonunion at twenty-four weeks after a clavicular fracture is an uncommon occurrence, although the prevalence is higher than previously reported. There are subgroups of individuals who appear to be predisposed to the development of this complication, either from intrinsic factors, such as age or gender, or from the type of injury sustained. The predictive models that we developed may be used clinically to counsel patients about the risk for the development of this complication immediately after the injury.Level of EvidencePrognostic study, Level I-1 (prospective study). See Instructions to Authors for a complete description of levels of evidence.

Recurrent posterior shoulder instability is an uncommon, debilitating condition in young adults that is being diagnosed with increasing frequency.Although a number of predisposing factors have been identified, their relative importance remains poorly understood.Poor results have been reported following operative intervention to treat recurrent posterior instability with nonanatomic techniques.The more recent development of lesion-specific surgery has improved clinical results, particularly when that surgery has been performed arthroscopically. Operative treatment is therefore being increasingly recommended at an earlier stage to patients who do not respond to supervised rehabilitation programs.

Posterior shoulder dislocations and fracture-dislocations are uncommon injuries that most often occur during seizures or as a result of high-energy trauma. Despite advances in imaging, they are frequently diagnosed late. Detection is facilitated by heightened clinical suspicion of the injury in high-risk individuals together with appropriate radiographic investigation. A wide variety of operative techniques, ranging from simple closed reduction to soft-tissue and bone stabilization procedures to prosthetic arthroplasty, are available to treat these injuries. Selection of the most appropriate treatment option is complex and multifactorial. Because of the rarity of these injuries, evidence-based treatment protocols are difficult to devise. Good functional outcomes are associated with early detection and treatment of isolated posterior dislocations that are associated with a small osseous defect and are stable following closed reduction. Poor prognostic factors include late diagnosis, a large anterior defect in the humeral head, deformity or arthrosis of the humeral head, an associated fracture of the proximal part of the humerus, and the need for an arthroplasty.

BackgroundThe optimal management of displaced fractures of the lateral end of the clavicle remains controversial. Successful results have been reported both with primary open reduction and internal fixation and with nonoperative treatment. The purpose of this study was to analyze the results of employing a policy of primary nonoperative treatment of displaced lateral fractures of the clavicle.MethodsWe treated a cohort of 127 patients who had sustained a displaced fracture of the lateral end of the clavicle. With the exception of seven patients who had immediate internal fixation, all of these patients were treated nonoperatively. At the time of follow-up, nineteen patients had died or could not be traced and fifteen were interviewed by telephone only. The remaining eighty-six patients were assessed clinically at an average of 6.2 years after the injury. All of these patients had a functional evaluation and were assessed radiographically.ResultsFourteen (14%) of the 101 patients who could be contacted had had symptoms severe enough to warrant delayed surgical intervention (Group I). The remaining eighty-seven patients had not undergone any surgery, and twenty-one of them (21% of the whole cohort) had a nonunion of the clavicular fracture. The average Constant score in the nonoperatively treated group was 93 points (range, 82 to 98 points). With the numbers available, there was no significant difference in the Constant or Short Form-36 (SF-36) scores between the patients with nonunion (Group II) and those in whom the fracture had healed (Group III) or between the patients who had been treated nonoperatively (Groups II and III) and those who had had delayed surgery (Group I). There was no significant difference between the SF-36 scores in any of the groups and the scores for age-matched controls in the general population.ConclusionsNonoperative treatment of most displaced lateral fractures of the clavicle in middle-aged and elderly patients achieves a good medium-term functional result. Symptoms that were severe enough to warrant a delayed reconstructive procedure developed in only 14% of the patients. Asymptomatic nonunion does not appear to adversely affect the functional outcome in the medium term.Level of EvidenceTherapeutic study, Level IV (case series [no, or historical, control group]). See Instructions to Authors for a complete description of levels of evidence.

BackgroundPrimary hemiarthroplasty of the shoulder is used to treat complex proximal humeral fractures, although the reported functional results following this method of treatment have varied widely. The aim of this study was to prospectively assess the prosthetic survival and functional outcomes in a large series of patients treated with shoulder hemiarthroplasty for a proximal humeral fracture. By determining the factors that affected the outcome, we also aimed to produce models that could be used clinically to estimate the functional outcome at one year following surgery.MethodsA thirteen-year observational cohort study of 163 consecutive patients treated with hemiarthroplasty for a proximal humeral fracture was performed. Twenty-five patients died or were lost to follow-up in the first year after treatment, leaving 138 patients who had assessment of shoulder function with use of the modified Constant score at one year postinjury.ResultsThe overall rate of prosthetic survival was 96.9% at one year, 95.3% at five years, and 93.9% at ten years. The overall median modified Constant score was 64 points at one year, with a typically good score for pain relief (median, 15 points) and poorer scores, with a greater scatter of values, for function (median, 12 points), range of motion (median, 24 points), and muscle power (median, 14 points). Of the factors that were assessed immediately after the injury, only patient age, the presence of a neurological deficit, tobacco usage, and alcohol consumption were significantly predictive of the one-year Constant score (p < 0.05). Of the factors that were assessed at six weeks postinjury, those that predicted the one-year Constant score included the age of the patient, the presence of a persistent neurological deficit, the need for an early reoperation, the degree of displacement of the prosthetic head from the central axis of the glenoid seen radiographically, and the degree of displacement of the tuberosities seen radiographically.ConclusionsPrimary shoulder hemiarthroplasty performed for the treatment of a proximal humeral fracture in medically fit and cooperative adults is associated with satisfactory prosthetic survival at an average of 6.3 years. Although the shoulder is usually free of pain following this procedure, the overall functional result, in terms of range of motion, function, and power, at one year varies. A good functional outcome can be anticipated for a younger individual who has no preoperative neurological deficit, no postoperative complications, and a satisfactory radiographic appearance of the shoulder at six weeks. The results are poorer in the larger group of elderly patients who undergo this procedure, especially if they have a neurological deficit, a postoperative complication requiring a reoperation, or an eccentrically located prosthesis with retracted tuberosities.Level of EvidencePrognostic study, Level II-1 (retospective study). See Instructions to Authors for a complete description of levels of evidence.

BACKGROUND:Although adult respiratory distress syndrome is an important early complication of blunt trauma, the epidemiology and risk factors for its development remain poorly defined. The aims of this study were to determine the prevalence and demographics of this complication in a prospective cohort series of patients admitted to the hospital following injury. We also assessed the contribution of the severity and pattern of the injury to the risk of this complication developing. By identifying factors associated with the highest risk of the development of adult respiratory distress syndrome, we aimed to produce guidelines to facilitate earlier detection. METHODS:We prospectively studied 7192 patients admitted to a single university hospital, over an eight-year period, for treatment of a traumatic injury. With the exception of patients who had sustained a hip fracture or who had been discharged within seventy-two hours after admission, all patients who required hospital admission following trauma, were older than thirteen years of age, and were a resident within the catchment area were included in the analysis. The prevalence and demographics of posttraumatic adult respiratory distress syndrome were identified for patients who had sustained musculoskeletal, thoracic, abdominal, and head injuries, either in isolation or in combination. The relative risks of this condition developing were calculated according to the injury pattern. Multiple logistic regression analysis was performed to identify the most highly significant predictors of the development of adult respiratory distress syndrome. RESULTS:Adult respiratory distress syndrome developed in thirty-six (0.5%) of the patients. The prevalence was significantly higher among younger patients (p = 0.002), and 83% of the cases followed high-energy trauma. The prevalence of adult respiratory distress syndrome after isolated thoracic, head, abdominal, or extremity injury was <1%. Patients with injuries to two anatomical regions had a higher prevalence (up to 2.9%), and those with injuries to three anatomical regions had an even higher prevalence (up to 10.2%). Multiple logistic regression analysis showed the Injury Severity Score, the presence of a femoral fracture, the combination of abdominal and extremity injuries, and observations of compromised physiological function on admission each to be an independent predictor of the later development of adult respiratory distress syndrome. CONCLUSIONS:The prevalence of adult respiratory distress syndrome increases with injury severity and combinations of injuries to more than one anatomical region. We have been able to quantify the importance and relative risks associated with these injuries. The implications of our findings with regard to facilitating early detection of this complication are discussed. LEVEL OF EVIDENCE:Prognostic study, Level I-1 (prospective study). See Instructions to Authors for a complete description of levels of evidence.

BackgroundThe functional results associated with nonoperative treatment of severely impacted valgus fractures of the proximal part of the humerus are poor, and these injuries are difficult to treat with minimally invasive percutaneous fixation techniques. The aim of this study was to review the functional and radiographic results and complications of a new operative technique in a series of twenty-five patients.MethodsOver a two-year period, we treated twenty-nine patients with a severely impacted valgus fracture of the proximal part of the humerus. Three patients were lost to follow-up and one died, leaving twenty-five patients who were available for the study. In all of the fractures, the head-shaft angle had been tilted into ≥160° of valgus and the greater tuberosity was displaced by >1 cm. All patients were treated with open reduction of the fracture, and the space created behind the humeral head was filled with Norian Skeletal Repair System (SRS) bone substitute. The fractures were stabilized with either screws or buttress plate fixation. Associated rotator cuff tears were repaired. All patients underwent functional outcome assessment with use of the Constant, DASH (Disabilities of the Arm, Shoulder and Hand), and SF-36 (Short Form-36) scores at one year, and twelve patients were followed for two years.ResultsAll fractures united within the first year, all reductions were maintained, and no patient had signs of osteonecrosis of the humeral head on the latest follow-up radiographs. At one year, the median Constant score was 80 points and the median DASH score was 22 points. The functional results continued to be satisfactory in the twelve patients who were followed for two years. The results in our series were better than those achieved in studies of nonoperative treatment of similar fracture configurations. There were six clinically relevant complications, although none required a reoperation and all six patients had a satisfactory short-term functional outcome.ConclusionsInternal fixation of severely impacted valgus fractures of the proximal part of the humerus, supplemented by Norian SRS bone substitute to fill the proximal humeral metaphyseal defect, produces good early functional and radiographic outcomes. Additional follow-up will be required to assess whether these initially satisfactory outcomes are maintained over the longer term.Level of EvidenceTherapeutic study, Level IV (case series [no, or historical, control group]). See Instructions to Authors for a complete description of levels of evidence.

BackgroundSubtrochanteric fractures of the femur that are caused by low-energy trauma are less common than other proximal femoral fractures, but they occur in a similar population of elderly individuals, who are often socially dependent and medically frail. Although a wide range of operative techniques have been used, cephalomedullary nailing theoretically provides the most minimally invasive and biomechanically stable means of treating these complex fractures. The purpose of the present review was to evaluate the functional outcome and perioperative complications associated with the use of a trochanteric-entry cephalomedullary nail to treat all low-energy subtrochanteric fractures that were seen at a single institution.MethodsOver an eight-year period, we used the long Gamma nail to treat a consecutive series of 302 local patients who had sustained a subtrochanteric fracture during low-energy trauma. The mortality, prevalence of complications, and functional outcome were prospectively assessed during the first year after the injury. Survival analysis was used to assess the rates of reoperation and implant revision during the first year after surgery.ResultsAt one year, seventy-four (24.5%) of the original 302 patients had died and seventeen (5.6%) had been lost to follow-up. The remaining 211 patients (69.9%) were evaluated with regard to the functional outcome and postoperative complications during the first year after the injury. As with other proximal femoral fractures in the elderly, there was an increased level of social dependence, an increase in the use of walking aids, and a reduction in mobility among survivors. Although eighty-eight (41.7%) of the 211 patients who were evaluated at one year after the injury had some degree of hip discomfort, only two described the pain as severe and disabling. Reoperation for the treatment of implant or fracture-related complications was required in twenty-seven (8.9%) of the 302 patients; however, only eighteen of these patients required nail revision, corresponding with a one-year nail-revision rate of 7.1% (95% confidence interval, 4.0% to 10.2%) on survival analysis. Of the 250 patients who survived for six months after the injury, five (2%) had a nonunion that was confirmed at the time of surgical exploration. Complications related to the proximal lag screw were seen in twelve of the original 302 patients, and a fracture distal to the tip of the nail occurred in five. Although superficial wound infection was relatively common, deep infection occurred in only five of the 302 patients.ConclusionsSubtrochanteric fractures caused by low-energy trauma are similar to other proximal femoral fractures, with a high mortality rate during the first year after the injury. Trochanteric-entry cephalomedullary nails are associated with an acceptable rate of perioperative complications and favorable functional outcomes.Level of EvidenceTherapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

The sensitivities of idealized large-eddy simulations (LESs) to variations of model configuration and forcing parameters on quantities of interest to wind power applications are examined. Simulated wind speed, turbulent fluxes, spectra and cospectra are assessed in relation to variations in two physical factors, geostrophic wind speed and surface roughness length, and several model configuration choices, including mesh size and grid aspect ratio, turbulence model, and numerical discretization schemes, in three different code bases. Two case studies representing nearly steady neutral and convective atmospheric boundary layer (ABL) flow conditions over nearly flat and homogeneous terrain were used to force and assess idealized LESs, using periodic lateral boundary conditions. Comparison with fast-response velocity measurements at 10 heights within the lowest 100 m indicates that most model configurations performed similarly overall, with differences between observed and predicted wind speed generally smaller than measurement variability. Simulations of convective conditions produced turbulence quantities and spectra that matched the observations well, while those of neutral simulations produced good predictions of stress, but smaller than observed magnitudes of turbulence kinetic energy, likely due to tower wakes influencing the measurements. While sensitivities to model configuration choices and variability in forcing can be considerable, idealized LESs are shown to reliably reproduce quantities of interest to wind energy applications within the lower ABL during quasi-ideal, nearly steady neutral and convective conditions over nearly flat and homogeneous terrain.

BACKGROUND:The functional results associated with nonoperative treatment of severely impacted valgus fractures of the proximal part of the humerus are poor, and these injuries are difficult to treat with minimally invasive percutaneous fixation techniques. The aim of this study was to review the functional and radiographic results and complications of a new operative technique in a series of twenty-five patients.METHODS:Over a two-year period, we treated twenty-nine patients with a severely impacted valgus fracture of the proximal part of the humerus. Three patients were lost to follow-up and one died, leaving twenty-five patients who were available for the study. In all of the fractures, the head-shaft angle had been tilted into ≥160° of valgus and the greater tuberosity was displaced by >1 cm. All patients were treated with open reduction of the fracture, and the space created behind the humeral head was filled with Norian Skeletal Repair System (SRS) bone substitute. The fractures were stabilized with either screws or buttress plate fixation. Associated rotator cuff tears were repaired. All patients underwent functional outcome assessment with use of the Constant, DASH (Disabilities of the Arm, Shoulder and Hand), and SF-36 (Short Form-36) scores at one year, and twelve patients were followed for two years.RESULTS:All fractures united within the first year, all reductions were maintained, and no patient had signs of osteonecrosis of the humeral head on the latest follow-up radiographs. At one year, the median Constant score was 80 points and the median DASH score was 22 points. The functional results continued to be satisfactory in the twelve patients who were followed for two years. The results in our series were better than those achieved in studies of nonoperative treatment of similar fracture configurations. There were six clinically relevant complications, although none required a reoperation and all six patients had a satisfactory short-term functional outcome.CONCLUSIONS:Internal fixation of severely impacted valgus fractures of the proximal part of the humerus, supplemented by Norian SRS bone substitute to fill the proximal humeral metaphyseal defect, produces good early functional and radiographic outcomes. Additional follow-up will be required to assess whether these initially satisfactory outcomes are maintained over the longer term.