Risk Factors for Cerebral Desaturation Events During Shoulder Surgery in the Beach Chair Position.

PURPOSE: The goals of this study were 2-fold: (1) to determine the risk factors for cerebral desaturation events (CDEs) after implementation of a comprehensive surgical and anesthetic protocol consisting of patient risk stratification, maintenance of normotensive anesthesia, and patient positioning in a staged fashion, and (2) to assess for subclinical neurologic decline associated with intraoperative ischemic events through cognitive testing. METHODS: One hundred patients undergoing shoulder surgery in the beach chair position were stratified for risk of CDE based on Framingham stroke criteria, body mass index (BMI), and history of cerebrovascular accidents. Cerebral oxygen saturation was monitored with near-infrared spectroscopy. As per a standardized protocol, mean arterial pressure was maintained between 70 and 90 mm Hg. The head was raised in 2 stages separated by 3 minutes. CDE were defined as >20% drop from baseline or <55% O2 absolute threshold. Patients completed a Mini-Mental State Examination during preoperative examination and at the first postoperative visit. RESULTS: The CDE rate was 4% overall and 4.3% in patients undergoing general anesthesia. Forty-five patients were in the higher risk category, and all CDEs occurred in that group. Patients with a Framingham score ≥ 10 or BMI ≥ 35 who underwent general anesthesia had an increased risk of CDE (P = .04). No significant change was noted in Mini-Mental State Examination scores between pre- and postoperative visits. No correlation was shown between CDE and history of diabetes, smoking, cardiovascular disease, or left ventricular hypertrophy. CONCLUSIONS: Our observed CDE rate was lower than previously reported rates, likely because of risk stratification, staged positioning, and normotensive anesthesia. Framingham score ≥ 10 and BMI ≥ 35 are risk factors for CDE in the beach chair position. LEVEL OF EVIDENCE: Level II, prospective observational study with >80% follow-up.

The timing of retears after arthroscopic rotator cuff repair.

BACKGROUND: Little is known about the time dependence of the failure rate of surgically repaired rotator cuffs. Retears are significant, as they are common and may lead to less satisfactory outcomes and additional operations. Their timing is critical foundational information for understanding failure mechanisms. However, this remains unclear. Currently, there exist a number of studies that have reported retear rates at specific time points. Combining data from these publications can reveal when cuffs retear, which will help inform expectations and guidelines for progression of activity after surgery. METHODS: PubMed, Medline, and Embase were searched for studies relating to rotator cuff repair. Abstracts and articles were evaluated on the basis of predefined inclusion and exclusion criteria. Data were extracted from those publications that satisfied all requirements, and regression analysis was performed. RESULTS: Thirteen articles were included in the final meta-analysis. Retear rates for medium tears increased for approximately 15 months and leveled off at approximately 20%. Retear rates for large tears progressed steadily for about 12 months and approached an upper limit of approximately 40%. Retear rates for massive tears ranged from 20% to 60%, but the distribution of retear rate over time for these cuff tears is not clear from these data. CONCLUSION: Retear rates for medium and large tears generally increase until at least 10-15 months after surgery, after which they are likely to level off. Retear rates for massive tears are variable and may follow a time course different from that of other tear sizes. Retear rates depend on size of the original tear.

A recurrent mutation in the BMP type I receptor ACVR1 causes inherited and sporadic fibrodysplasia ossificans progressiva.

Fibrodysplasia ossificans progressiva (FOP) is a rare autosomal dominant disorder of skeletal malformations and progressive extraskeletal ossification. We mapped FOP to chromosome 2q23-24 by linkage analysis and identified an identical heterozygous mutation (617G --> A; R206H) in the glycine-serine (GS) activation domain of ACVR1, a BMP type I receptor, in all affected individuals examined. Protein modeling predicts destabilization of the GS domain, consistent with constitutive activation of ACVR1 as the underlying cause of the ectopic chondrogenesis, osteogenesis and joint fusions seen in FOP.

Biceps detachment decreases joint damage in a rotator cuff tear rat model.

BACKGROUND: Pathology in the long head of the biceps tendon often occurs in patients with rotator cuff tears. Arthroscopic tenotomy is the most common treatment. However, the role of the long head of the biceps at the shoulder and the consequences of surgical detachment on the remaining shoulder structures remain unknown. QUESTIONS/PURPOSES: We hypothesized that detachment of the long head of the biceps, in the presence of supraspinatus and infraspinatus tears, would decrease shoulder function and decrease mechanical and histologic properties of both the subscapularis tendon and the glenoid articular cartilage. METHODS: We detached the supraspinatus and infraspinatus or the supraspinatus, infraspinatus, and long head of the biceps after 4 weeks of overuse in a rat model. Animals were gradually returned to overuse activity after detachment. At 8 weeks, the subscapularis and glenoid cartilage biomechanical and histologic properties were evaluated and compared. RESULTS: The supraspinatus, infraspinatus, and long head of the biceps group had a decreased change in braking and vertical force. [corrected]. This group also had an increased upper and lower subscapularis modulus but without any differences in glenoid cartilage modulus. Finally, this group had a significantly lower cell density in both the upper and lower subscapularis tendons, although cartilage histology was not different. CONCLUSIONS: Detachment of the long head of the biceps tendon in the presence of a posterior-superior cuff tear resulted in improved shoulder function and less joint damage in this animal model. CLINICAL RELEVANCE: This study provides evidence in an animal model that supports the use of tenotomy for the management of long head of the biceps pathology in the presence of a two-tendon cuff tear. However, long-term clinical trials are required.

Addressing glenoid bone deficiency and asymmetric posterior erosion in shoulder arthroplasty.

Glenoid bone deficiency and eccentric posterior wear are difficult problems faced by shoulder arthroplasty surgeons. Numerous options and techniques exist for addressing these issues. Hemiarthroplasty with concentric glenoid reaming may be a viable alternative in motivated patients in whom glenoid component failure is a concern. Total shoulder arthroplasty has been shown to provide durable pain relief and excellent function in patients, and numerous methods and techniques can assist in addressing bone loss and eccentric wear. However, the ideal amount of version correction in cases of severe retroversion has not yet been established. Asymmetric reaming is a commonly used technique to address glenoid version, but correction of severe retroversion may compromise bone stock and component fixation. Bone grafting is a technically demanding alternative for uncontained defects and has mixed clinical results. Specialized glenoid implants with posterior augmentation have been created to assist the surgeon in correcting glenoid version without compromising bone stock, but clinical data on these implants are still pending. Custom implants or instruments based on each patient's unique glenoid anatomy may hold promise. In elderly, sedentary patients in whom bone stock and soft-tissue balance are concerns, reverse total shoulder arthroplasty may be less technically demanding while still providing satisfactory pain relief and functional improvements.

Intra-articular changes precede extra-articular changes in the biceps tendon after rotator cuff tears in a rat model.

HYPOTHESIS: Biceps tendon pathology is common with rotator cuff tears. The mechanisms for biceps changes, and therefore its optimal treatment, are unknown. Our objective was to determine the effect of rotator cuff tears on regional biceps tendon pathology. We hypothesized that histologic and compositional changes would appear before organizational changes, both would appear before mechanical changes, and changes would begin at the tendon's insertion site. MATERIALS AND METHODS: Detachment of supraspinatus and infraspinatus tendons or sham surgery was done in 65 Sprague-Dawley rats. Rats were euthanized at 1, 4, or 8 weeks for regional measurements of histologic, compositional, organizational (1, 4 and 8 weeks), or mechanical properties (4 and 8 weeks only). RESULTS: One week after tendon detachments, decreased organization and more rounded cell shape were found in the intra-articular space of the biceps tendon. Aggrecan expression was increased along the entire length of the tendon, whereas all other compositional changes were only at the tendon's proximal insertion into bone. With time, this disorganization and more rounded cell shape extended the length of the tendon. Organizational and cell shape changes also preceded detrimental mechanical changes: decreased modulus in the intra-articular space was found after 8 weeks. CONCLUSIONS: Results support a degenerative component to pathology in the biceps tendon. In addition, changes resembling a tendon exposed to compressive loading occurring first in the intra-articular space indicate that the biceps tendon plays an increased role as a load-bearing structure against the humeral head in the presence of rotator cuff tears.

Total shoulder arthroplasty in older patients: increased perioperative morbidity?

BACKGROUND: More elderly patients are becoming candidates for total shoulder arthroplasty with an increase in frequency of the procedure paralleling the rise in other total joint arthroplasties. Controversy still exists, however, regarding the perioperative morbidity of total joint arthroplasty in elderly patients, particularly those 80 years of age and older. QUESTIONS/PURPOSES: We asked whether perioperative complications and mortality, transfusion requirements, inpatient length of stay, and discharge disposition after total shoulder arthroplasty were similar in patients 80 years and older compared with those in younger patients. METHODS: We retrospectively compared the 90-day complications, mortality, and other perioperative variables after total shoulder arthroplasty in 40 patients (43 shoulders) aged 80 years and older (Group A; mean age, 82 years) with 46 patients (47 shoulders) younger than 70 years (Group B; mean age, 61 years). RESULTS: We found no differences in complication rates between Group A and B, including systemic (26% versus 11%) and local (5% versus 9%) complications or major (7% versus 2%) and minor (23% versus 17%) complications. There were no deaths in either group. Group A had an increased transfusion requirement (16% versus 2%) and a decreased number of direct to home discharges (67% versus 98%). Presence of systemic complications predicted increased length of stay in patients overall and in Group A patients. CONCLUSIONS: Total shoulder arthroplasty can be performed in patients 80 years and older with rates of perioperative complications and mortalities comparable to those of younger patients, although these older patients may require a longer period of institutional care before return to home and may be more likely to require a blood transfusion. LEVEL OF EVIDENCE: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Decreased loading after rotator cuff tears leads to improved biceps tendon properties in a rat model.

BACKGROUND: The purpose of this study was to elucidate the mechanism of biceps tendon changes after rotator cuff tears. We hypothesized that increased loading on the biceps tendon after rotator cuff tears will result in further detrimental changes whereas decreased loading will result in increased organization and more normal tendon composition. In addition, we hypothesized that changes with altered loading will begin at the proximal insertion into bone and progress along the tendon length at later time points. MATERIALS AND METHODS: Supraspinatus and infraspinatus tendon detachments in rats were followed by various loading protocols at various time points. Regional changes in cellularity, cell shape, collagen organization, and matrix proteins of the long head of the biceps tendon were determined by histologic measures and immunohistochemistry. RESULTS: Increased loading after detachments resulted in more disorganized collagen after only 1 week and compositional changes by 4 weeks. By 8 weeks, decreased loading resulted in increased organization, decreased cellularity, a more elongated cell shape, and more normal tendon composition. Organizational changes with increased loading began in the intra-articular space and progressed along the tendon length with time. CONCLUSIONS: Combined with previous findings of decreased mechanics with increased loading, these results show that increased compressive loading away from the proximal insertion into bone is a mechanism for biceps tendon pathology in the presence of rotator cuff tears. The striking improvements with decreased loading further support increased loading as a mechanism for biceps tendon pathology because removal of this load led to improvements in tendon histology, organization, and composition.

Risk factors associated with atraumatic posterolateral rotatory instability.

BACKGROUND: Traumatic posterolateral rotatory instability after elbow dislocation or fracture dislocation has been well described. However, few reports cover atraumatic posterolateral rotatory instability as a cause of lateral-sided elbow pain. We assessed the risk factors and epidemiology of atraumatic posterolateral rotatory instability in a case-control study. METHODS: A retrospective review of all patients treated operatively for atraumatic posterolateral rotatory instability during a 6-year period was compared with a group of patients with extensor carpi radialis brevis tendinopathy without instability treated during the same time period. Bivariate and multiple logistic regression statistical analyses were used to investigate the following risk factors: gender, age, hand dominance, diabetes, smoking, body mass index, corticosteroid injection history, and duration of symptoms. Disabilities of the Arm, Shoulder, and Hand and pain scores were obtained preoperatively and postoperatively. RESULTS: Thirteen patients with atraumatic posterolateral rotatory instability were compared with 12 patients with extensor carpi radialis brevis tendinopathy. Multivariate analysis revealed patients with atraumatic posterolateral rotatory instability were more likely to have multiple corticosteroid injections (P = .05) and present with a longer duration of symptoms (P = .03). Postoperative pain scores improved in both groups. CONCLUSIONS: Atraumatic posterolateral rotatory instability should be considered in the differential diagnosis of lateral elbow when patients present with a protracted clinical course. Statistically, posterolateral rotatory instability patients more often present with a history of multiple corticosteroid injections.

Preoperative tendon retraction, not smoking, is a risk factor for failure with continuity after rotator cuff repair.

BACKGROUND: Smoking is a poor prognostic factor for healing after rotator cuff repair and is associated with inferior results. We hypothesized that smokers would have higher recurrent tear rates and more postoperative myotendinous junction (MTJ) retraction in healed repairs than nonsmokers three months postoperatively. METHODS: Rotator cuff repairs (RCRs) were retrospectively reviewed over a 2-year period. Patients underwent magnetic resonance imaging (MRI) within 6 months prior to surgery and again at 3 months postoperatively. Seventy-nine patients were included and stratified by smokers versus nonsmokers. Baseline patient demographics, tear characteristics, and surgical factors were collected. Preoperative and postoperative MRIs were assessed to quantify the MTJ position and to establish the recurrent tear rate. RESULTS: For the total cohort (nonsmokers, n = 56; smokers, n = 23), significant differences in age, race, and traumatic onset of injury existed between groups. There were no significant differences in recurrent tear between smokers (26%) and nonsmokers (27%), but nonsmokers were more satisfied. For patients with healed RCRs (nonsmokers, n = 41; smokers, n = 17), there were significant differences in race. On univariate analysis, nonsmokers had a significantly more lateral MTJ postoperatively (P = 0.05). On multivariable regression analysis, medialized postoperative MTJ position in healed cuffs was driven only by greater preoperative rotator cuff retraction preoperatively. There were no significant differences in MTJ position based on smoking status for patients with healed RCRs. CONCLUSION: Smoking does not appear to be an independent risk factor for postoperative MTJ retraction in healed RCRs, also known as failure in continuity. Preoperative tear size and retraction play the biggest roles in predicting postoperative MTJ position, regardless of smoking status. There are no significant differences in patient-reported outcomes for patients with healed RCRs, but nonsmokers had more satisfaction following RCR in the total cohort. LEVEL OF EVIDENCE: Level III; Retrospective cohort study; Diagnostic study.

Circulating osteogenic precursor cells in heterotopic bone formation.

Cells with osteogenic potential can be found in a variety of tissues. Here we show that circulating osteogenic precursor (COP) cells, a bone marrow-derived type I collagen+/CD45+ subpopulation of mononuclear adherent cells, are present in early preosseous fibroproliferative lesions in patients with fibrodysplasia ossificans progressiva (FOP) and nucleate heterotopic ossification (HO) in a murine in vivo implantation assay. Blood samples from patients with FOP with active episodes of HO contain significantly higher numbers of clonally derived COP cell colonies than patients with stable disease or unaffected individuals. The highest level of COP cells was found in a patient just before the clinical onset of an HO exacerbation. Our studies show that even COP cells derived from an unaffected individual can contribute to HO in genetically susceptible host tissue. The possibility that circulating, hematopoietic-derived cells with osteogenic potential can seed inflammatory sites has tremendous implications and, to our knowledge, represents the first example of their involvement in clinical HO. Thus, bone formation is not limited to cells of the mesenchymal lineage, and circulating cells of hematopoietic origin can also serve as osteogenic precursors at remote sites of tissue inflammation.

Classic and atypical fibrodysplasia ossificans progressiva (FOP) phenotypes are caused by mutations in the bone morphogenetic protein (BMP) type I receptor ACVR1.

Fibrodysplasia ossificans progressiva (FOP) is an autosomal dominant human disorder of bone formation that causes developmental skeletal defects and extensive debilitating bone formation within soft connective tissues (heterotopic ossification) during childhood. All patients with classic clinical features of FOP (great toe malformations and progressive heterotopic ossification) have previously been found to carry the same heterozygous mutation (c.617G>A; p.R206H) in the glycine and serine residue (GS) activation domain of activin A type I receptor/activin-like kinase 2 (ACVR1/ALK2), a bone morphogenetic protein (BMP) type I receptor. Among patients with FOP-like heterotopic ossification and/or toe malformations, we identified patients with clinical features unusual for FOP. These atypical FOP patients form two classes: FOP-plus (classic defining features of FOP plus one or more atypical features) and FOP variants (major variations in one or both of the two classic defining features of FOP). All patients examined have heterozygous ACVR1 missense mutations in conserved amino acids. While the recurrent c.617G>A; p.R206H mutation was found in all cases of classic FOP and most cases of FOP-plus, novel ACVR1 mutations occur in the FOP variants and two cases of FOP-plus. Protein structure homology modeling predicts that each of the amino acid substitutions activates the ACVR1 protein to enhance receptor signaling. We observed genotype-phenotype correlation between some ACVR1 mutations and the age of onset of heterotopic ossification or on embryonic skeletal development.

Fibrodysplasia ossificans progressiva.

Fibrodysplasia ossificans progressiva (FOP), a rare and disabling genetic condition of congenital skeletal malformations and progressive heterotopic ossification (HO), is the most catastrophic disorder of HO in humans. Episodic disease flare-ups are precipitated by soft tissue injury, and immobility is cumulative. Recently, a recurrent mutation in activin receptor IA/activin-like kinase 2 (ACVR1/ALK2), a bone morphogenetic protein (BMP) type I receptor, was reported in all sporadic and familial cases of classic FOP, making this one of the most highly specific disease-causing mutations in the human genome. The discovery of the FOP gene establishes a critical milestone in understanding FOP, reveals a highly conserved target for drug development in the transforming growth factor (TGF)-beta/BMP signalling pathway, and compels therapeutic approaches for the development of small molecule signal transduction inhibitors for ACVR1/ALK2. Present management involves early diagnosis, assiduous avoidance of iatrogenic harm, and symptomatic amelioration of painful flare-ups. Effective therapies for FOP, and possibly for other common conditions of HO, may potentially be based on future interventions that block ACVR1/ALK2 signalling.

Prevalence and risk factors for kidney stones in fibrodysplasia ossificans progressiva.

The worldwide prevalence and risk factors for kidney stones in patients with fibrodysplasia ossificans progressiva (FOP) are unknown. We conducted a survey of 383 patient-members of the International Fibrodysplasia Ossificans Progressiva Association, comprising the entire global membership of the international FOP community. Two hundred seven patients from 31 nations and 6 continents (54%) responded. Nineteen of 207 respondents had kidney stones, revealing a worldwide prevalence of 9.2%. In a confirmatory follow-up study of subjects participating in a longitudinal FOP natural history study, 9 of 114 individuals reported a history of kidney stones (7.9%). In both study populations patients with kidney stones were found to be more functionally impaired compared to those without nephrolithiasis. The prevalence of kidney stones in the adult FOP population of the Unites States was 15.8% (9/57 individuals) compared to a sex- and age-weighted prevalence of 4.5% (p=4×10-5) in the general population. Although geographical variation exists, patients with FOP have an approximately three-fold greater prevalence of kidney stones than the general population. This unusually high prevalence may be due to high bone turnover from chronic immobilization, or to unknown mechanistic effects of the activating FOP mutation in activin A receptor, type I/activin-like kinase-2 (ACVR1/ALK2), increasing the disease burden and morbidity in this already disabling condition.

Hematopoietic stem-cell contribution to ectopic skeletogenesis.

BACKGROUND: Fibrodysplasia ossificans progressiva is a rare genetic disorder of ectopic skeletogenesis associated with dysregulation of bone morphogenetic protein (BMP) signaling. Hematopoietic cells have been implicated in the ectopic skeletogenesis of fibrodysplasia ossificans progressiva, and their replacement has been postulated as a possible cure. However, the definitive contribution of hematopoietic cells to the pathogenesis of ectopic skeletogenesis remains obscure. METHODS: We employed both careful clinical observation and in vivo murine transplantation studies to more precisely determine the contribution of hematopoietic cells to ectopic skeletogenesis. We identified a patient with fibrodysplasia ossificans progressiva who had undergone bone marrow transplantation for the treatment of intercurrent aplastic anemia twenty-five years earlier and investigated whether the clinical course of the fibrodysplasia ossificans progressiva had been influenced by bone marrow replacement or immunosuppression, or both. In complementary studies, we transplanted hematopoietic stem cells from constitutively expressing LacZ transgenic mice to identify the contribution of hematopoietic cells to BMP4-induced heterotopic ossification, a histopathologic model of fibrodysplasia ossificans progressiva. RESULTS: We found that replacement of hematopoietic cells was not sufficient to prevent ectopic skeletogenesis in the patient with fibrodysplasia ossificans progressiva but pharmacologic suppression of the apparently normal donor immune system following transplantation in the new host modulated the activity of the fibrodysplasia ossificans progressiva and diminished the expression of skeletal ectopia. In complementary murine transplantation studies, we found that cells of hematopoietic origin contributed to the early inflammatory and late marrow-repopulating stages of BMP4-induced heterotopic ossification but were not represented in the fibroproliferative, chondrogenic, or osteogenic stages of heterotopic ossification. Interestingly, both recombinant human BMP4 induction in an animal model and the dysregulated BMP signaling pathway in a patient with fibrodysplasia ossificans progressiva were sufficient to recruit at least two populations of cells, one of hematopoietic origin and at least one of non-hematopoietic origin, that contribute to the formation of an ectopic skeleton. CONCLUSIONS: Taken together, these findings demonstrate that bone marrow transplantation did not cure fibrodysplasia ossificans progressiva in the patient in this study, most likely because the hematopoietic cell population is not the site, or at least not the dominant site, of the intrinsic dysregulation of the BMP signaling pathway in fibrodysplasia ossificans progressiva. However, following transplantation of bone marrow from a presumably normal donor, immunosuppression of the immune system appeared to ameliorate activation of ectopic skeletogenesis in a genetically susceptible host. Thus, cells of hematopoietic origin may contribute to the formation of an ectopic skeleton, although they are not sufficient to initiate the process alone.

Use of small intestine submucosa in a rat model of acute and chronic rotator cuff tear.

Augmentation materials for rotator cuff tears, such as small intestine submucosa (SIS), have been used with the goal of improving outcome. Knowledge is limited on the use of SIS in animal models of acute and chronic rotator cuff tears. We hypothesized that the use of SIS in the surgical management of full thickness supraspinatus tears would improve histologic and biomechanical properties. Results show temporal improvements in several histologic parameters. Both acute and chronic injuries repaired with SIS have similar and increased mechanical properties respectively, compared to those repaired without SIS. In general, acute repairs with SIS were comparable to acute repairs without SIS. In chronic repairs, the use of SIS significantly reduced the cross sectional area of the healing tendon and increased the modulus. These results provide information on the use of SIS for rotator cuff repairs.

Neer Award 2005: Peripheral nerve function during shoulder arthroplasty using intraoperative nerve monitoring.

The incidence of neurologic injury after shoulder arthroplasty has been reported to be 1% to 4%. However, the true incidence may be higher, because injury is identified only clinically and examination of the post-arthroplasty shoulder is difficult. This study used intraoperative nerve monitoring to identify the incidence, pattern, and predisposing factors for nerve injury during shoulder arthroplasty. Continuous intraoperative monitoring of the brachial plexus was performed in 30 consecutive patients undergoing shoulder arthroplasty. Impending intraoperative compromise of nerve function was signaled by sustained neurotonic electromyographic activity or greater than 50% amplitude attenuation of transcranial electrical motor evoked potentials (or both). Arm and retractor positions were recorded and adjusted to relieve tension. Patients with intraoperative nerve alerts underwent diagnostic electromyography at least 4 weeks postoperatively. Of the patients, 17 (56.7%) had 30 episodes of nerve dysfunction (ie, nerve alerts) during surgery. None of these 30 nerve alerts returned to baseline with retractor removal alone. Of the 30 alerts, 23 (76.7%) returned to baseline after repositioning of the arm into a neutral position. Postoperative electromyography results were positive in 4 of 7 patients (57.1%) who did not have a return to baseline transcranial electrical MEPs intraoperatively and in 1 of 10 (10%) whose nerve function did return to baseline. In all cases of positive postoperative electromyographic results, the pattern of nerve involvement matched the pattern of intraoperative nerve dysfunction. The affected nerves included the following: combined (ie, mixed plexopathy) (46.7%), musculocutaneous (20%), axillary (16.7%), ulnar (10%), and radial (6.7%). Prior shoulder surgery and passive external rotation of less than 10 degrees were associated with an increased incidence of nerve dysfunction (P < .05). The incidence of nerve injury during shoulder arthroplasty is likely greater than reported. Positioning of the arm at the extremes of motion should be minimized. Patients with decreased motion (<10 degrees passive external rotation with the arm at the side) and a history of prior open shoulder surgery are at higher risk for nerve injury and should be counseled on the increased risk. This patient population may also be considered for routine nerve monitoring.

Arthroscopic Cortical Button Stabilization of Isolated Acute Neer Type II Fractures of the Distal Clavicle.

Neer type II distal clavicle fractures are inherently unstable. The purpose of this study was to review the outcome of Neer type II distal clavicle fractures arthroscopically treated using a suspensory cortical button technique. Between 2008 and 2012, a total of 17 Neer type IIB fractures were managed operatively at the authors' institution. Functional outcomes were assessed using the pain score, the Disabilities of the Arm, Shoulder and Hand score, the Penn Shoulder Score, and the American Shoulder and Elbow Surgeons score. Radiographic union was also assessed. At a mean of 1 year, the mean pain score was 0.9±1.1, the mean Disabilities of the Arm, Shoulder and Hand score was 10.9±11.1, the mean Penn Shoulder Score was 90.3±7.9, and the mean American Shoulder and Elbow Surgeons score was 90.1±10.1. Radiographic union occurred in 14 patients. An all-arthroscopic surgical fixation of Neer type II distal clavicle fractures using a suspensory cortical button technique can result in a predictable outcome with a low complication rate. [Orthopedics. 2017; 40(6):e1050-e1054.].

The development and application of a risk stratification index system for outpatient shoulder arthroscopy patient management-a single academic center's experience.

BACKGROUND: Our goal was to develop a risk stratification index (RSI) that could guide management of our patients. We hypothesized that the risks of unexpected overstay admission (OS) and emergency department (ED) transfer are predictable on the basis of patient factors for elective outpatient shoulder arthroscopic surgery. METHODS: We first identified 124,860 subjects who received shoulder arthroscopic surgery in the Healthcare Cost and Utilization Project database. We next conducted multivariable regression analysis to identify risk factors associated with unanticipated OS or ED transfer. The risk factors were then adopted to construct the RSI. We last applied the RSI into our practice and prospectively collected outcome data between August 2014 and June 2015. RESULTS: The significant risk factors included arrhythmia, chronic obstructive pulmonary disease, diabetes, obesity, neurologic disease with function impairment, and general anesthesia. All significant risk factors were then adopted to calculate the RSI with equal weight assignment. Simulated analysis concluded that a patient with 2 or fewer risk factors would carry a theoretical rate for OS or ED events of 0.73%. A total of 583 shoulder arthroscopy procedures were performed, among which 472 (81.0%) patients passed the RSI and were successfully managed in the outpatient surgical center without any admission. There were 111 (19.0%) subjects with procedures performed in the main hospital, with 2 unexpected admissions (1.8%). CONCLUSION: We developed an RSI tool for shoulder arthroscopic surgery with an existing national database. It is our conclusion that the RSI system is an effective tool to optimize clinical practice. However, over time, a longer follow-up period might provide more convincing evidence.