In the Era of Tranexamic Acid, are Type and Screens for Primary Total Joint Arthroplasty Obsolete?

BACKGROUND: Advances in technique and perioperative blood management have improved transfusion rates following unilateral primary total joint arthroplasty and led some centers to change their preoperative blood ordering protocols. The purpose of this study is to determine whether deleting type and screens (T&S) from preoperative order sets was safe for patients undergoing primary total knee (TKA) and total hip arthroplasty (THA) and to identify patients who required allogenic blood transfusion. METHODS: Prospectively collected data were reviewed to identify any patient with a hemoglobin (Hgb) drawn within 30 days of surgery who received a transfusion following a unilateral primary TKA or THA. RESULTS: A total of 1255 patients met inclusion criteria. Of the total, 682 (54%) were TKAs and 573 (46%) were THAs. The mean preoperative Hgb was 11.5 g/dL with an average delta Hgb of 3.6 g/dL on postoperative day 1. No patient required an intraoperative transfusion. Fourteen patients (mean age and body mass index, 67.9 and 29.0) required a transfusion (1.1%) for postoperative blood loss anemia. Of those transfused, 13 (93%) of the patients underwent THA with the mean estimated blood loss of 378.6 mL. The total cost for a patient obtaining a T&S is $191.27. CONCLUSION: In our series, the risk of blood transfusion was rare (1.1%) and occurred only secondary to postoperative blood loss anemia. There were no cases of intraoperative complication requiring urgent or emergent blood transfusion. Removing T&S from standard order sets for patients undergoing primary TKA or THA appears to be a safe and cost-effective practice.

The prevalence of rotator cuff pathology in the setting of acute proximal biceps tendon rupture.

BACKGROUND: The prevalence and severity of concomitant rotator cuff pathology in the setting of proximal biceps tendon ruptures are poorly understood. Concomitant rotator cuff disease may have important implications in the prognosis and natural history of this shoulder condition. Therefore, an observational cohort of patients with an acute rupture of the long head of the biceps tendon (LHBT) was evaluated to determine the prevalence and severity of concomitant rotator cuff disease. METHODS: Thirty consecutive patients diagnosed with acute proximal biceps tendon rupture were prospectively enrolled. Magnetic resonance imaging of the affected shoulder was obtained in 27 patients and reviewed by a fellowship-trained orthopedic surgeon. RESULTS: The cohort consisted of 20 men (74%) and 7 women (26%) (mean age, 61.0 years [range, 42-78 years]). The dominant side was involved in 20 injuries (74%), and a low-energy trauma mechanism of injury was involved in 23 (85%). Of the patients, 11 (41%) reported a history of antecedent shoulder pain. Magnetic resonance imaging assessment revealed that 93% of patients had evidence of rotator cuff disease, including 13 full-thickness tears. Of the full-thickness tears, 3 were small, 6 medium, 2 large, and 2 massive. Pathology of the subscapularis tendon was identified in 7 patients (26%). CONCLUSION: In this cohort, we found LHBT rupture to be highly correlated with the presence of rotator cuff disease, with the majority of patients presenting with full-thickness tears of the supraspinatus. These findings may have important implications in the treatment and prognosis of patients who present with acute LHBT ruptures.

Liver X receptor agonists augment human islet function through activation of anaplerotic pathways and glycerolipid/free fatty acid cycling.

Recent studies in rodent models suggest that liver X receptors (LXRs) may play an important role in the maintenance of glucose homeostasis and islet function. To date, however, no studies have comprehensively examined the role of LXRs in human islet biology. Human islets were isolated from non-diabetic donors and incubated in the presence or absence of two synthetic LXR agonists, TO-901317 and GW3965, under conditions of low and high glucose. LXR agonist treatment enhanced both basal and stimulated insulin secretion, which corresponded to an increase in the expression of genes involved in anaplerosis and reverse cholesterol transport. Furthermore, enzyme activity of pyruvate carboxylase, a key regulator of pyruvate cycling and anaplerotic flux, was also increased. Whereas LXR agonist treatment up-regulated known downstream targets involved in lipogenesis, we observed no increase in the accumulation of intra-islet triglyceride at the dose of agonist used in our study. Moreover, LXR activation increased expression of the genes encoding hormone-sensitive lipase and adipose triglyceride lipase, two enzymes involved in lipolysis and glycerolipid/free fatty acid cycling. Chronically, insulin gene expression was increased after treatment with TO-901317, and this was accompanied by increased Pdx-1 nuclear protein levels and enhanced Pdx-1 binding to the insulin promoter. In conclusion, our data suggest that LXR agonists have a direct effect on the islet to augment insulin secretion and expression, actions that should be considered either as therapeutic or unintended side effects, as these agents are developed for clinical use.

Development of insulin-producing cells from primitive biologic precursors.

PURPOSE OF REVIEW: The differentiation of pluripotent and multipotent stem cells into insulin-producing cells has the potential to create a renewable supply of replacement beta cells with tremendous utility in the treatment of diabetes. The purpose of this review is to summarize recent advancements in the field, with emphasis on the limitations of this technology as it relates to the beta cell. RECENT FINDINGS: Multiple groups have developed successful in-vitro protocols to differentiate human embryonic stem cells and selected tissue specific stem cells into progenitors capable of insulin production and glucose-stimulated insulin secretion. The resulting cells are immature beta cell-like cells that coexpress multiple islet hormones and lack the full complement of genes necessary for normal function. Protocols that include in-vivo maturation in immune-compromised mice produce cells with a more mature phenotype. SUMMARY: Although tremendous progress has been made in differentiating stem cells into insulin-producing cells, there is still more research needed to produce a fully functional adult beta cell.

Cognitive Training for Robotic Arm-Assisted Unicompartmental Knee Arthroplasty through a Surgical Simulation Mobile Application.

Advances in mobile device technology combined with the implementation of surgical simulation have led to the development of novel applications (apps) as a potential learning tool for surgical trainees. Touch Surgery (TS) (Kinosis Limited, London, United Kingdom) is a mobile-based app that combines cognitive task analysis with a virtual reality medium to familiarize the user with a surgical procedure through interactive rehearsal. The purpose of this study was to compare the educational efficacy of the TS app with a traditional paper-based learning program in performing a robotic arm-assisted unicompartmental knee arthroplasty. Twelve participants (four interns, four residents, four adult reconstructive fellows) were randomized to a paper-based technique guide or learning modules from the Mako Partial Knee (Stryker, Mahwah, NJ) TS app. Trainees were subjected to a baseline pretest. After preparing with the allocated training tool, participants completed an immediate posttest followed by a retention test administered 3 weeks later. The TS simulation group demonstrated greater improvement (22% score increase; p = 0.001) in posttest assessment compared with the control group (10% score increase; p = 0. 09). The TS simulation group demonstrated better information recall compared with the control group based on the score differential following the 3-week retention test. This randomized comparative study demonstrated that the TS app was better than traditional paper-based learning for both immediate posttest performance and long-term information recall of the Mako robotic arm-assisted unicompartmental knee arthroplasty. Surgical simulation apps may be an effective learning tool for surgical trainees.

Early femoral condyle insufficiency fractures after total knee arthroplasty: treatment with delayed surgery and femoral component revision.

BACKGROUND: Periprosthetic fracture following total knee arthroplasty (TKA) is usually associated with a traumatic event and typically treated with fracture fixation techniques. However, we report on a series of patients with early atraumatic condyle fractures that occurred as a result of insufficiency of the unloaded preoperative femoral condyle treated with delayed reconstruction. METHODS: We retrospectively reviewed a series of 7 patients who sustained femoral condyle fractures following TKA and evaluated risk factors for insufficiency. RESULTS: There were 6 females and 1 male with an average age of 65.5 (range, 63-75) years and an average body mass index of 29.4 (range, 27-32). Fracture occurred on average 24.9 days from the index surgery and secondary to a low energy mechanism. Five patients had valgus alignment (mean, 15.2°) preoperatively and sustained fracture of the unloaded medial femoral condyle. Two patients had varus alignment (mean, 7.0°) preoperatively and both fractured the unloaded lateral condyle. One patient underwent early intervention requiring distal femoral replacement secondary to femoral bone loss. The remaining 6 patients underwent delayed surgery for an average of 6 weeks to allow for fracture healing followed by femoral component revision. At last follow-up (average, 48.5 months), 1 patient required a tibial component revision; however, no revision of the femoral component was required. CONCLUSIONS: Early femoral condyle insufficiency fractures following TKA may be a risk in females with poor bone quality and preoperative valgus alignment. Delayed surgery and femoral component revision is a treatment strategy that prevented the need for other tertiary reconstruction.

Peroxisome proliferator-activated receptor gamma activation restores islet function in diabetic mice through reduction of endoplasmic reticulum stress and maintenance of euchromatin structure.

The nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR-gamma) is an important target in diabetes therapy, but its direct role, if any, in the restoration of islet function has remained controversial. To identify potential molecular mechanisms of PPAR-gamma in the islet, we treated diabetic or glucose-intolerant mice with the PPAR-gamma agonist pioglitazone or with a control. Treated mice exhibited significantly improved glycemic control, corresponding to increased serum insulin and enhanced glucose-stimulated insulin release and Ca(2+) responses from isolated islets in vitro. This improved islet function was at least partially attributed to significant upregulation of the islet genes Irs1, SERCA, Ins1/2, and Glut2 in treated animals. The restoration of the Ins1/2 and Glut2 genes corresponded to a two- to threefold increase in the euchromatin marker histone H3 dimethyl-Lys4 at their respective promoters and was coincident with increased nuclear occupancy of the islet methyltransferase Set7/9. Analysis of diabetic islets in vitro suggested that these effects resulting from the presence of the PPAR-gamma agonist may be secondary to improvements in endoplasmic reticulum stress. Consistent with this possibility, incubation of thapsigargin-treated INS-1 beta cells with the PPAR-gamma agonist resulted in the reduction of endoplasmic reticulum stress and restoration of Pdx1 protein levels and Set7/9 nuclear occupancy. We conclude that PPAR-gamma agonists exert a direct effect in diabetic islets to reduce endoplasmic reticulum stress and enhance Pdx1 levels, leading to favorable alterations of the islet gene chromatin architecture.