Benjamin W. Sears

Glenoid bone loss in primary total shoulder arthroplasty: evaluation and management.

Abstract Glenohumeral osteoarthritis is the most common reason for shoulder replacement. Total shoulder arthroplasty provides reliable pain relief and restoration of function, with implant survivorship reported at 85% at 15 years. Glenoid component wear and aseptic loosening are among the most common reasons for revision. Glenoid wear characteristics have been correlated with, among other things, the degree of anatomic glenoid version correction. Anatomic glenoid reconstruction is particularly challenging in the presence of glenoid bone deficiency. Walch classified glenoid morphology into five types: type A, centered, without posterior subluxation but with minor erosion (A1) or major erosion (A2); type B, posteriorly subluxated (B1) or posteriorly subluxated with posterior glenoid erosion (B2); and type C, excessive glenoid retroversion. The type A glenoid represents only 59% of patients; thus, the need to address glenoid deformity is common. Methods of correction include asymmetric reaming of the anterior glenoid, bone grafting of the posterior glenoid, and implanting a specialized glenoid component with posterior augmentation. In many cases of type C or hypoplastic glenoid, the humerus is concentrically reduced in the deficient glenoid and glenoid deformity may not need to be corrected. Severely hypoplastic glenoid may require the use of bone‐sparing glenoid components or reverse total shoulder arthroplasty.

Cerebral desaturation events during shoulder arthroscopy in the beach chair position: patient risk factors and neurocognitive effects.

BACKGROUND Patients undergoing shoulder surgery in the beach chair position may be at increased risk for serious neurocognitive complications due to cerebral ischemia. We sought to define the incidence, patient risk factors, and clinical sequelae of intraoperative cerebral desaturation events. METHODS Regional cerebral tissue oxygen saturation (rSO2) was monitored intra-operatively using near-infrared spectroscopy (NIRS) on 50 consecutive patients. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was administered to each patient pre- and postoperatively. Intra-operative decreases in rSO2 of 20% or greater were defined as cerebral desaturation events (CDE). The association between intraoperative CDE and postoperative cognitive decline was assessed. RESULTS The incidence of intraoperative CDE in our series was 18% (9/50). Increased body mass index (BMI) was found to have a statistically significant association with intraoperative CDE (mean BMI 37.32 vs 28.59, P < .0001). There was no statistical significance in pre- vs postoperative RBANS either in composite scores or any of the sub-indices in either group. CONCLUSION The degree and duration of cerebral ischemia required to produce neurocognitive dysfunction in this patient population remains undefined; however, cerebral oximetry with NIRS allows prompt identification and treatment of decreased cerebral perfusion decreasing the risk of this event. Increased BMI was found to be a statistically significant patient risk factor for the development of intra-operative CDE. The transient intra-operative CDEs were not associated with postoperative cognitive dysfunction in our patient series. We believe protocols aimed at detecting and reversing CDE minimize the risk of neurocognitive dysfunction and improve patient safety.

Posttraumatic elbow arthritis in the young adult: evaluation and management.

Abstract Degenerative joint disease following trauma to the elbow is difficult to manage in any patient. However, this condition becomes substantially more challenging in the young, active population. Increased activity demands and limited functional capacity of total elbow arthroplasty mean that joint arthroplasty should be regarded as a salvage procedure. The primary goal of treatment is to restore a pain‐free or minimally painful functional joint while preserving future surgical options. This requires accurate assessment of the primary patient complaint, be it terminal pain and stiffness or pain along the entire arc of motion. Patients who report stiffness and pain at terminal motion may benefit from arthroscopic or open osteocapsular débridement. Those with advanced degenerative changes and pain throughout the entire arc of motion may require joint resurfacing with interposition arthroplasty, partial joint arthroplasty, or total joint arthroplasty.

Pathoanatomy and Clinical Correlates of the Immunoinflammatory Response Following Orthopaedic Trauma

&NA; The natural inflammatory response to major trauma may be associated with the development of a systemic inflammatory state, remote multiorgan failure, and death. Although a controlled inflammatory response is beneficial, an exaggerated response can cause serious adverse systemic effects. Early identification of highrisk patients, based on inflammatory markers and genomic predisposition, should help direct intervention in terms of surgical stabilization and biologic response modification. Currently, two markers of immune reactivity, interleukin‐6 and human leukocyte antigen‐DR class II molecules, appear to have the most potential for regular use in predicting the clinical course and outcome in trauma patients; however, the ability to measure markers of inflammation is still limited at many hospitals. With improving technology and increasing research interest, understanding of the significance of the immunoinflammatory response system in injured patients will continue to evolve.

Cerebral Desaturation During Shoulder Arthroscopy: A Prospective Observational Study

BackgroundPatients undergoing arthroscopic shoulder surgery in the beach chair position may be at increased risk for serious neurocognitive complications as a result of cerebral ischemia.Questions/purposesWe sought to define the (1) incidence; (2) timing; and (3) magnitude of intraoperative cerebral desaturation events (CDEs) in subjects undergoing arthroscopic shoulder surgery in the beach chair position, as well as whether (4) the length of surgery was an independent risk factor for intraoperative CDEs.MethodsRegional cerebral tissue oxygen saturation (rSO2) was monitored intraoperatively using near-infrared spectroscopy on 51 consecutive patients undergoing arthroscopic shoulder surgery in the beach chair position. Intraoperative decreases in rSO2 of 20% or greater were defined as CDEs.ResultsThe incidence of intraoperative CDEs in our series was 18% (nine of 51). Among the patients demonstrating CDE (n = 9), the mean time to onset of initial CDE was 18 minutes 38 seconds postinduction. Of those experiencing CDEs, the mean maximal decrease in rSO2 was 32% from preoperative baseline per patient. Additionally, the mean number of separate CDE instances was 1.89 in this patient population with an average duration of 3 minutes 3 seconds per instance. There was no statistically significant difference (p = 0.202) between patients demonstrating CDEs and those without in regard to length of surgery (95 versus 88 minutes).ConclusionsThe degree and duration of cerebral ischemia required to produce neurocognitive dysfunction in this patient population remains undefined; however, cerebral oximetry with near-infrared spectroscopy allows prompt identification and treatment of decreased cerebral perfusion. We believe protocols aimed at detecting and reversing CDE may improve patient safety.Level of EvidenceLevel III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Antioxidant Therapy Attenuates Deficient Bone Fracture Repair Associated with Binge Alcohol Exposure

Objectives: Alcohol consumption is a known risk factor for traumatic injuries of all types and has been shown to produce detrimental effects on bone metabolism. Although the mechanisms responsible for these detrimental effects are not well characterized, oxidative stress from alcohol exposure appears to play a central role. This study was designed to examine the effect of a short-term binge alcohol consumption pattern on fracture repair and the effect of an antioxidant, N-acetylcysteine, on fracture healing after binge alcohol consumption. Methods: One hundred forty-four adult male Sprague-Dawley rats underwent unilateral closed femur fracture after injection of either saline or alcohol to simulate a binge alcohol cycle. Animals in the antioxidant treatment group received daily N-acetylcysteine after fracture. Femurs were harvested at 1, 2, 4, and 6 weeks after injury and underwent biomechanical testing and histologic analysis. Results: Binge alcohol administration was associated with significant decreases in biomechanical strength at 1- and 2-week time points with a trend toward decreased strength at 4- and 6-week time points as well. Alcohol-treated animals had less cartilage component within the fracture callus and healed primarily by intramembranous ossification. Administration of N-acetylcysteine in alcohol-treated animals improved biomechanical strength to levels comparable to the control animals and was associated with increased endochondral ossification. Conclusions: Our results indicate that binge alcohol alters the quality of fracture healing after a traumatic injury and that concurrent administration of an antioxidant is able to reverse these effects.

Binge Alcohol Exposure Modulates Rodent Expression of Biomarkers of the Immunoinflammatory Response to Orthopaedic Trauma

BACKGROUND Alcohol is a known modulator of the immune system and host-defense response. Alcohol abuse is common in trauma patients, although the influence of alcohol intoxication on the inflammatory response following major orthopaedic injury remains unknown. The aim of this investigation was to examine the influence of binge alcohol exposure on biomarkers of the systemic inflammatory response following bilateral traumatic femoral fracture in a rodent model. METHODS Ninety-two Sprague-Dawley rats were administered intraperitoneal injections of either saline solution or alcohol for three days. These animals then underwent a sham procedure or bilateral femoral intramedullary pinning and mid-diaphyseal closed fracture via blunt guillotine. The animals were killed at specific time points after the injury. Serum and lung tissue were collected, and twenty-five inflammatory markers were analyzed by immunoassay. Histological sections of lung tissue were evaluated by a board-certified pathologist. RESULTS Bilateral femoral fracture significantly (p < 0.05) increased multiple serum biomarkers of inflammation. Binge alcohol treatment prior to injury significantly suppressed the increase in serum levels of interleukin (IL)-6, white blood cells, IL-2, IL-10, and C-reactive protein after the fracture. However, alcohol-treated animals were found to have increased pulmonary levels of IL-6, IL-1β, IL-2, and macrophage inflammatory protein-1α following bilateral femoral fracture. In addition, lung tissue harvested following alcohol treatment and injury demonstrated increased pathologic changes, including parenchymal, alveolar, and peribronchial leukocyte infiltration and significantly elevated pulmonary wet-to-dry ratio, indicative of pulmonary edema. CONCLUSIONS Our results indicate that acute alcohol intake prior to bilateral femoral fracture with fixation in rats modulates the inflammatory response after injury in a tissue-dependent manner. Although serum biomarkers of inflammation were suppressed in alcohol-treated animals following injury, several measures of pulmonary inflammation including cytokine levels, histological changes, and findings of pulmonary edema were significantly increased following fracture with the presence of alcohol.

Correlation of measurable serum markers of inflammation with lung levels following bilateral femur fracture in a rat model.

Introduction Evaluation of the systemic inflammatory status following major orthopedic trauma has become an important adjunct in basing post-injury clinical decisions. In the present study, we examined the correlation of serum and lung inflammatory marker levels following bilateral femur fracture. Materials and methods 45 Sprague Dawley rats underwent sham operation or bilateral femoral intramedullary pinning and mid-diaphyseal closed fracture via blunt guillotine. Animals were euthanized at specific time points after injury. Serum and lung tissue were collected, and 24 inflammatory markers were analyzed by immunoassay. Lung histology was evaluated by a blinded pathologist. Results Bilateral femur fracture significantly increased serum markers of inflammation including interleukin (IL)-2, IL-6, IL-10, GM-CSF, KC/GRO, MCP-1, and WBC. Femur fracture significantly increased serum and lung levels of IL-1a and KC/GRO at 6 hours. Lung levels of IL-6 demonstrated a trend towards significance. Histologic changes in pulmonary tissue after fracture included pulmonary edema and bone elements including cellular hematopoietic cells, bone fragments and marrow emboli. Discussion and conclusion Our results indicate that bilateral femur fracture with fixation in rats results in increases in serum markers of inflammation. Among the inflammatory markers measured, rise in the serum KC/GRO (CINC-1), a homolog to human IL-8, correlated with elevated levels of lung KC/GRO. Ultimately, analysis of serum levels of KC/GRO (CINC-1), or human IL-8, may be a useful adjunct to guide clinical decisions regarding surgical timing.

An anthropometric analysis to derive formulae for calculating the dimensions of anatomically shaped humeral heads.

BACKGROUND The elliptical shape of the humeral head has been vaguely described, but a more detailed mathematical description is lacking. The primary goal of this study was to create formulae to describe the mathematical relationships between the various dimensions of anatomically shaped humeral heads. METHODS Three-dimensional computer models of 79 proximal humeri derived from computed tomography scans (white subjects, 47 male and 32 female; ages, 17-87 years) were studied. Linear regression analysis of the obtained humeral measurements was performed, and Pearson correlation coefficient (R) values were calculated. To substantiate the results of the linear regression analysis, Welch t-test was used to compare various parameters of small, medium, and large humeral heads. RESULTS Formulae for calculating humeral head height, diameters of the base of the humeral head in the frontal and sagittal planes, and radii of curvature in the frontal and sagittal planes were derived from the linear regression plots that were found to have strong (1 ≥ R ≥ 0.50) correlations. By Welch t-test, differences between the 3 head sizes were statistically significant in each case (P ≤ .022). The elliptical shape of the base of the humeral head was found to elongate with increasing humeral head size. CONCLUSIONS Mathematical formulae relating various humeral head dimensional measurements are presented. The formulae derived in this study may be useful for the design of future prosthetic shoulder systems in which the goal is to replicate normal anatomy. This is the first study to describe that the elliptical shape of the base of the humeral head elongates as head size increases.

Effect of head and neck positioning on cerebral perfusion during shoulder arthroscopy in beach chair position.

The aim of this prospective cohort study was to investigate the effect of head and neck positioning on cerebral perfusion during shoulder arthroscopy in the beach chair position. Regional cerebral tissue oxygen saturation (rSO2) was monitored intraoperatively using near-infrared spectroscopy on 51 consecutive patients undergoing arthroscopic shoulder surgery in the beach chair position. The head of each subject was manipulated by the examiner and sequentially positioned for 45 seconds in terminal flexion, extension, bilateral rotation, and bilateral lateral bending. Decreases in rSO2 of 20% or greater from baseline were defined as a cerebral desaturation event (CDE). The association between head and neck position and cerebral perfusion was assessed. Eight percent of patients (4/51) experienced CDE during head and neck positioning. Body mass index was found to be a risk factor for CDE (p = .05). When comparing preoperative baseline rSO2 to intraoperative supine and intraoperative upright rSO2, there was no significant decrease in saturation levels for any of the six tested positions. Frequent intraoperative evaluations of the head and neck position as well as careful preoperative positioning may reduce the risk of position-related complications in patients undergoing elective shoulder arthroscopy in the beach chair position. In this studys patient population, however, head and neck position was not found to cause significant cerebral desaturation for the time period tested compared to preoperative baselines.