Stemless components lead to improved radiographic restoration of humeral head anatomy compared with short-stemmed components in total shoulder arthroplasty.

BACKGROUND: Restoring the native center of rotation (COR) in total shoulder arthroplasty (TSA) has been shown to improve postsurgical function, subjective outcomes, and implant longevity. The primary purpose of this study was to compare postoperative radiographic restoration of the humeral COR between short-stem and stemless humeral implants by evaluating the mean COR shift between the 2 techniques. Secondary outcomes evaluated were comparisons of COR shift outliers, humeral head implant thickness and diameter, direction of COR shift, and neck-shaft angle (NSA). METHODS: This study was a multicenter retrospective comparative study using a consecutive series of primary anatomic TSA patients who received either a short-stem or stemless humeral implant. Radiographically, COR and NSA were measured by 2 fellowship-trained surgeons using the best-fit circle technique on immediate postoperative Grashey radiographs. RESULTS: A total of 229 patients formed the final cohort for analysis that included 89 short stems and 140 stemless components. The mean COR shift for short stems was 2.7 mm (±1.4 mm) compared with 2.1 mm (±0.9 mm) for stemless implants (P < .001). The percentage of short-stem implant patients with a >2 mm COR difference from native was 66.0% (n = 62) compared with 47.4% (n = 64) for stemless (P = .006). The percentage of short-stem patients with a >4 mm COR difference from native was 17.0% (n = 16) compared with 3.0% (n = 4) for stemless (P < .001). The mean humeral implant head thickness for short stems was 18.7 ± 2.2 mm compared with 17.2 ± 1.3 mm for stemless implants (P < .001). The mean humeral head diameter for short stems was 48.7 ± 4.4 mm compared with 45.5 ± 3.5 mm for stemless implants (P < .001). The NSA for the short-stem cohort was 136.7° (±3.6°) compared with 133.5° (±6.0°) for stemless (P < .001). CONCLUSIONS: Stemless prostheses placed during TSA achieved improved restoration of humeral head COR and were less likely to have significant COR outliers compared with short-stem implants.

Trends in open shoulder surgery among early career orthopedic surgeons: who is doing what?

BACKGROUND: The incidence of various open shoulder procedures has changed over time. In addition, various fellowships provide overlapping training in open shoulder surgery. There is a lack of information regarding the relationship between surgeon training and open shoulder procedure type and incidence in early career orthopedic surgeons. METHODS: The American Board of Orthopaedic Surgery Part-II database was queried from 2002 to 2016 for reported open shoulder procedures. The procedures were categorized as follows: arthroplasty, revision arthroplasty, open instability, trauma, and open rotator cuff. We evaluated procedure trends as well as their relationship to surgeon fellowship categorized by Sports, Shoulder/Elbow, Hand, Trauma, and "Other" fellowship as well as no fellowship training. We additionally evaluated complication data as it related to procedure, fellowship category, and volume. RESULTS: Over the 2002-2016 study period, there were increasing cases of arthroplasty, revision arthroplasty, and trauma (P < .001). There were decreasing cases in open instability and open rotator cuff (P < .001). Those with Sports training reported the largest overall share of open shoulder cases. Those with Shoulder/Elbow training reported an increasing overall share of arthroplasty cases and higher per candidate case numbers. The percentage of early career orthopedic surgeons reporting 5 or more arthroplasty cases was highest among Shoulder/Elbow candidates (P < .001). Across all procedures, those without fellowship training were least likely to report a complication (odds ratio [OR], 0.76; 95% confidence interval, 0.67-0.86; P < .001). Shoulder/Elbow candidates were least likely to report an arthroplasty complication (OR, 0.84, P = .03) as was any surgeon reporting 5 or more arthroplasty cases (OR, 0.81; 95% confidence interval, 0.70-0.94; P = .006). CONCLUSION: The type and incidence of open shoulder surgery procedures continues to change. Among early career surgeons, those with more specific shoulder training are now performing the majority of arthroplasty-related procedures, and early career volume inversely correlates with complications.

Medial Unloader Braces and Lateral Heel Wedges Do not Alter Gait Biomechanics in Healthy Young Adults.

Context: Orthotic devices such as medial unloader knee braces and lateral heel wedges may limit cartilage loading following trauma or surgical repair. However, little is known regarding their effects on gait biomechanics in young, healthy individuals who are at risk of cartilage injury during physical activity due to greater athletic exposure compared with older adults. Objective: Determine the effect of medial unloader braces and lateral heel wedges on lower-extremity kinematics and kinetics in healthy, young adults. Design: Cross-sectional crossover design. Setting: Laboratory setting. Patients: Healthy, young adults who were recreationally active (30 min/d for 3 d/wk) between 18 and 35 years of age, who were free from orthopedic injury for at least 6 months, and with no history of lower-extremity orthopedic surgery. Interventions: All subjects completed normal over ground walking with a medial unloader brace at 2 different tension settings and a lateral heel wedge for a total of 4 separate walking conditions. Main Outcome Measures: Frontal plane knee angle at heel strike, peak varus angle, peak internal knee valgus moment, and frontal plane angular impulse were compared across conditions. Results: The medial unloader brace at 50% (-2.04° [3.53°]) and 100% (-1.80° [3.63°]) maximum load placed the knee in a significantly more valgus orientation at heel strike compared with the lateral heel wedge condition (-0.05° [2.85°]). However, this difference has minimal clinical relevance. Neither of the orthotic devices altered knee kinematics or kinetics relative to the control condition. Conclusions: Although effective in older adults and individuals with varus knee alignment, medial unloader braces and lateral heel wedges do not influence gait biomechanics in young, healthy individuals.

The effect of feedback timing on category learning and feedback processing in younger and older adults.

Introduction: Corrective feedback can be received immediately after an action or with a temporal delay. Neuroimaging studies suggest that immediate and delayed feedback are processed by the striatum and medial temporal lobes (MTL), respectively. Age-related changes in the striatum and MTL may influence the efficiency of feedback-based learning in older adults. The current study leverages event-related potentials (ERPs) to evaluate age-related differences in immediate and delayed feedback processing and consequences for learning. The feedback-related negativity (FRN) captures activity in the frontostriatal circuit while the N170 is hypothesized to reflect MTL activation. Methods: 18 younger (Myears = 24.4) and 20 older (Myears = 65.5) adults completed learning tasks with immediate and delayed feedback. For each group, learning outcomes and ERP magnitudes were evaluated across timing conditions. Results: Younger adults learned better than older adults in the immediate timing condition. This performance difference was associated with a typical FRN signature in younger but not older adults. For older adults, impaired processing of immediate feedback in the striatum may have negatively impacted learning. Conversely, learning was comparable across groups when feedback was delayed. For both groups, delayed feedback was associated with a larger magnitude N170 relative to immediate feedback, suggesting greater MTL activation. Discussion and conclusion: Delaying feedback may increase MTL involvement and, for older adults, improve category learning. Age-related neural changes may differentially affect MTL- and striatal-dependent learning. Future research can evaluate the locus of age-related learning differences and how feedback can be manipulated to optimize learning across the lifespan.

Access to outpatient care for adult rotator cuff patients with private insurance versus Medicaid in North Carolina.

BACKGROUND: Access to orthopaedic care for pediatric patients has been shown in previous studies to be decreased for patients with Medicaid compared with those with private insurance. The relationship between type of insurance and access to care for adult patients with acute rotator cuff tears has not yet been examined. This study aimed to determine if type of health insurance would have an impact on access to care for an adult patient with an acute rotator cuff tear. METHODS: Seventy-one orthopaedic surgery practices within the state of North Carolina were randomly selected and contacted on 2 different occasions separated by 3 weeks. The practices were presented with an appointment request for a fictitious 42-year-old man with an acute rotator cuff tear. Insurance status was reported as Medicaid for the first call and as private insurance during the second call. RESULTS: Of the 71 practices contacted, 51 (72%) offered the patient with Medicaid an appointment, whereas 68 (96%) offered the patient with private insurance an appointment. The difference in these rates was statistically significant (P < .001). The likelihood of patients with private insurance obtaining an appointment was 8.8 times higher than that of patients with Medicaid (95% CI: 2.5, 31.5). CONCLUSION: For patients with acute rotator cuff tears, access to care is decreased for those with Medicaid compared with those with private insurance. Patients with private insurance are 8.8 times more likely than those with Medicaid to obtain an appointment. LEVEL OF EVIDENCE: Basic science, survey study.

Improvement Trajectories in Patient-Reported Outcomes Between Males and Females After Anterior Cruciate Ligament Reconstruction.

CONTEXT: Patient-reported outcomes (PROs) are used to track recovery and inform clinical decision-making after anterior cruciate ligament reconstruction (ACLR). Whether sex influences the trajectory of improvements in PROs over time post-ACLR remains unclear. OBJECTIVES: To (1) examine the effect of sex on the association between months post-ACLR and Knee injury and Osteoarthritis Outcome Score (KOOS) Quality of Life (QOL) scores in individuals with ACLR and (2) assess sex differences in the KOOS QOL score at selected timepoints post-ACLR. DESIGN: Cross-sectional study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 133 females (20± 3 years) and 85 males (22 ± 4 years) within 6 to 60 months of primary, unilateral ACLR. MAIN OUTCOME MEASURE(S): The KOOS QOL was completed at a single follow-up timepoint post-ACLR. A multivariate linear regression model was calculated to assess the interaction of sex on the association between months post-ACLR and KOOS QOL score. Sex-specific linear regression models were then used to predict KOOS QOL estimated marginal means at each clinical timepoint (6, 12, 24, 36, 48, and 60 months post-ACLR) and compare the sexes. RESULTS: In the primary model (R2 = 0.16, P < .0001), a significant interaction existed between sex and time post-ACLR (ß = -0.46, P < .01). Greater months post-ACLR were associated with better KOOS QOL scores for males (R2 = 0.29, ß = 0.69, P < .001); months post-ACLR was a weaker predictor of KOOS QOL scores for females (R2 = 0.04, ß = 0.23, P < .02). Estimated marginal means for KOOS QOL scores were greater for males than females at 36 months (t210 = 2.76, P < .01), 48 months (t210 = 3.02, P < .01), and 60 months (t210 = 3.09, P = .02) post-ACLR. CONCLUSIONS: Males exhibited PRO improvement post-ACLR as the months post-ACLR increased, whereas females did not demonstrate the same magnitude of linear increase in KOOS QOL score. Females may require extended intervention to improve clinical outcomes post-ACLR and address a plateau in QOL score.

Bone bruising severity after anterior cruciate ligament rupture predicts elevation of chemokine MCP-1 associated with osteoarthritis.

PURPOSE: Anterior cruciate ligament rupture is associated with characteristic bone contusions in approximately 80% of patients, and these have been correlated with higher pain scores. Bone bruising may indicate joint damage that increases inflammation and the likelihood of posttraumatic osteoarthritis. We sought to characterize the severity of bone bruising following acute anterior cruciate ligament injury and determine if it correlates with synovial fluid and serum levels of the proinflammatory chemokine monocyte chemoattractant protein-1 associated with posttraumatic osteoarthritis. METHODS: This was a retrospective analysis of data collected prospectively from January 2014 through December 2016. All patients who sustained an acute ligament rupture were evaluated within 15 days of injury, obtained a magnetic resonance imaging study, and underwent bone-patellar-tendon-bone autograft reconstruction were offered enrollment. The overall severity of bone bruising on magnetic resonance imaging was graded (sum of 0-3 grades in 13 sectors of the articular surfaces). Serum and synovial fluid levels of monocyte chemoattractant protein-1 were measured within 14 days of injury, and serum levels were again measured 6 and 12 months following surgery. Separate univariate linear regression models were constructed to determine the association between monocyte chemoattractant protein-1 and bone bruising severity at each time point. RESULTS: Forty-eight subjects were included in this study. They had a mean age of 21.4 years and were 48% female. Median overall bone bruising severity was 5 (range 0-14). Severity of bone bruising correlated with higher synovial fluid concentrations of monocyte chemoattractant protein-1 preoperatively (R2 = 0.18, p = 0.009) and with serum concentrations at 12 months post-reconstruction (R2 = 0.12, p = 0.04). CONCLUSIONS: The severity of bone bruising following anterior cruciate ligament rupture is associated with higher levels of the proinflammatory cytokine monocyte chemoattractant protein-1 in synovial fluid acutely post-injury and in serum 12-months following anterior cruciate ligament reconstruction. This suggests that severe bone bruising on magnetic resonance imaging after ligament rupture may indicate increased risk for persistent joint inflammation and posttraumatic osteoarthritis. LEVEL OF EVIDENCE: III - retrospective cohort study.

Rate of infection following revision anterior cruciate ligament reconstruction and associated patient- and surgeon-dependent risk factors: Retrospective results from MOON and MARS data collected from 2002 to 2011.

Infection is a rare occurrence after revision anterior cruciate ligament reconstruction (rACLR). Because of the low rates of infection, it has been difficult to identify risk factors for infection in this patient population. The purpose of this study was to report the rate of infection following rACLR and assess whether infection is associated with patient- and surgeon-dependent risk factors. We reviewed two large prospective cohorts to identify patients with postoperative infections following rACLR. Age, sex, body mass index (BMI), smoking status, history of diabetes, and graft choice were recorded for each patient. The association of these factors with postoperative infection following rACLR was assessed. There were 1423 rACLR cases in the combined cohort, with 9 (0.6%) reporting postoperative infections. Allografts had a higher risk of infection than autografts (odds ratio, 6.8; 95% CI, 0.9-54.5; p = .045). Diabetes (odds ratio, 28.6; 95% CI, 5.5-149.9; p = .004) was a risk factor for infection. Patient age, sex, BMI, and smoking status were not associated with risk of infection after rACLR.

Associations between cartilage proteoglycan density and patient outcomes 12months following anterior cruciate ligament reconstruction.

BACKGROUND: Lower proteoglycan density (PGD) of the articular cartilage may be an early marker of osteoarthritis following anterior cruciate ligament (ACL) reconstruction (ACL-R). The purpose this study was to determine associations between the Knee Injury and Osteoarthritis Outcomes Score (KOOS) and PGD of the articular cartilage in the femur and tibia 12-months following ACL-R. METHODS: We evaluated KOOS pain, symptoms, function in activities of daily living (ADL), function in sport and recreation (Sport), and quality of life (QOL), as well as PGD using T1rho magnetic resonance imaging in 18 individuals 12.50±0.70months (these are all mean±standard deviation) following unilateral ACL-R (10 females, eight males; 22.39±4.19years; Marx Score=10.93±3.33). Medial and lateral load-bearing portions of the femoral and tibial condyles were sectioned into three (anterior, central and posterior) regions of interest (ROIs). T1rho relaxation times in the ACL-R knee were normalized to the same regions of interest in the non-surgical knees. Alpha levels were set at P≤0.05. RESULTS: Worse KOOS outcomes were significantly associated with greater T1rho relaxation time ratios in the posterior-lateral femoral condyle [pain (r=-0.54), ADL (r=-0.56), Sport (r=-0.62) and QOL (r=-0.59)] central-lateral femoral condyle [Sport (r=-0.48) and QOL (r=-0.42)], and the anterior-medial femoral condyle [Sport (r=-0.46) and QOL (r=-0.40)]. There were no significant associations between the KOOS and T1rho outcomes for tibial ROI. CONCLUSIONS: Lower PGD of the femoral cartilage in the ACL-R knees was associated with worse patient-reported outcomes.

Walking gait asymmetries 6 months following anterior cruciate ligament reconstruction predict 12-month patient-reported outcomes.

The study sought to determine the association between gait biomechanics (vertical ground reaction force [vGRF], vGRF loading rate [vGRF-LR]) collected 6 months following anterior cruciate ligament reconstruction (ACLR) with patient-reported outcomes at 12 months following ACLR. Walking gait biomechanics and all subsections of the Knee Injury and Osteoarthritis Outcomes Score (KOOS) were collected at 6 and 12 months following ACLR, respectively, in 25 individuals with a unilateral ACLR. Peak vGRF and peak instantaneous vGRF-LR were extracted from the first 50% of the stance phase. Limb symmetry indices (LSI) were used to normalize outcomes in the ACLR limb to that of the uninjured limb (ACLR/uninjured). Linear regression analyses were used to determine associations between biomechanical outcomes and KOOS while accounting for walking speed. Receiver operator characteristic curves were used to determine the accuracy of 6-month biomechanical outcomes for identifying individuals with acceptable patient-reported outcomes, using previously defined KOOS cut-off scores, 12 months post-ACLR. Individuals with lower peak vGRF LSI 6 months post-ACLR demonstrated worse patient-reported outcomes (KOOS Pain, Activities of Daily life, Sport and Recreation, Quality of Life) at the 12-month exam. A peak vGRF LSI ≥0.99 6 months following ACLR associated with 13.33× higher odds of reporting acceptable patient-reported outcomes 12 months post-ACLR. Lesser peak vGRF LSI during walking at 6-months post-ACLR may be a critical indicator of worse future patient-reported outcomes. Clinical significance achieving early symmetrical lower extremity loading and minimizing under-loading of the ACLR limb during walking may be a potential therapeutic target for improving patient-reported outcomes post-ACLR. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2932-2940, 2018.

Surgical Trends in the Treatment of Meniscal Tears: Analysis of Data From the American Board of Orthopaedic Surgery Certification Examination Database.

BACKGROUND: The indications and criteria for meniscal repair are expanding in parallel with new understanding in biomechanics, joint pathophysiology, and increased physician education. PURPOSE: To describe the practice patterns of arthroscopic meniscal treatment in recent years, compare the trends of arthroscopic meniscal repair versus arthroscopic meniscectomy, and compare sports fellowship-trained versus non-sports fellowship-trained surgeons in terms of arthroscopic meniscal treatment techniques among American Board of Orthopaedic Surgery (ABOS) candidates from 2004 to 2012. STUDY DESIGN: Descriptive epidemiology study. METHODS: The ABOS database was used to identify cases of meniscal repair, partial meniscectomy, and anterior cruciate ligament (ACL) reconstruction from 2004 to 2012. The number of surgeons contributing cases for each calendar year was also recorded, along with the number who had sports fellowship training. Rates were calculated as the number of procedures per surgeon per year. Trends were analyzed using Poisson regression analysis to model the rate of each procedure over time. RESULTS: The rate of all meniscal procedures per surgeon decreased 12% from 18.4 cases per surgeon in 2004 to 16.2 cases per surgeon in 2012. There was a smaller decrease for sports fellowship-trained surgeons (7%) than for non-sports fellowship-trained surgeons (32%). The rate of meniscal repair cases per surgeon increased 37% from 1.6 to 2.2 cases per surgeon. The rate of meniscectomy cases decreased 17% from 16.8 to 14.0 cases per surgeon. When comparing fellowship-trained surgeons to non-fellowship-trained surgeons, there was no significant difference in meniscal repair rates over time. There was a decrease of 35% in rates of meniscectomy among non-fellowship-trained surgeons compared with 11% among fellowship-trained surgeons. CONCLUSION: This study provides insight into the current practice trends of recent orthopaedic training graduates in the treatment of meniscal tears. The results suggest that reported meniscal procedures have decreased overall among ABOS candidates but that meniscal repair cases have increased. The findings support the recent shift toward evidence-based medicine, with changing practice patterns that may reflect the dissemination of recent findings from large, high-quality research studies in this field.

Spinal cord injury-induced changes in breathing are not due to supraspinal plasticity in turtles (Pseudemys scripta).

After occurrence of spinal cord injury, it is not known whether the respiratory rhythm generator undergoes plasticity to compensate for respiratory insufficiency. To test this hypothesis, respiratory variables were measured in adult semiaquatic turtles using a pneumotachograph attached to a breathing chamber on a water-filled tank. Turtles breathed room air (2 h) before being challenged with two consecutive 2-h bouts of hypercapnia (2 and 6% CO2 or 4 and 8% CO2). Turtles were spinalized at dorsal segments D8-D10 so that only pectoral girdle movement was used for breathing. Measurements were repeated at 4 and 8 wk postinjury. For turtles breathing room air, breathing frequency, tidal volume, and ventilation were not altered by spinalization; single-breath (singlet) frequency increased sevenfold. Spinalized turtles breathing 6-8% CO2 had lower ventilation due to decreased frequency and tidal volume, episodic breathing (breaths/episode) was reduced, and singlet breathing was increased sevenfold. Respiratory variables in sham-operated turtles were unaltered by surgery. Isolated brain stems from control, spinalized, and sham turtles produced similar respiratory motor output and responded the same to increased bath pH. Thus spinalized turtles compensated for pelvic girdle loss while breathing room air but were unable to compensate during hypercapnic challenges. Because isolated brain stems from control and spinalized turtles had similar respiratory motor output and chemosensitivity, breathing changes in spinalized turtles in vivo were probably not due to plasticity within the respiratory rhythm generator. Instead, caudal spinal cord damage probably disrupts spinobulbar pathways that are necessary for normal breathing.

Separation of craniopagus twins in the era of modern neuroimaging, interventional neuroradiology, and frameless stereotaxy.

INTRODUCTION: Craniopagus twinning is a rare embryological event occurring in 1 in 2.5 million births. CASE REPORT: We present our recent experience with the separation of total vertical craniopagus twins in the modern era of neuroimaging and interventional neuroradiology. Three-dimensional CT images revealed the twins' heads were axially rotated 30 degrees. MRI showed deficient dura between the brains of the twins, and some sharing of parietal brain tissue. Cerebral angiography showed a dominant arterial circulation of one twin with unilateral middle cerebral artery (MCA) branches feeding the other twin. The twins shared a common superior sagittal sinus in its middle segment where a circular sinus was formed. Prior to surgery, endovascular separation of the twins' arterial and venous circulations was achieved in part using tantalum coils for the MCA feeders in one twin, and balloon occlusion of the anterior superior sagittal sinus of the other. Using the ISG wand intraoperatively, surgery proceeded stepwise and included the circumferential removal of bone and opening of the dura, separation of the twins' brains along leptomeningeal planes, and identification of the major draining veins from the superficial cerebral cortex. DISCUSSION: The separation of craniopagus twins demands a multidisciplinary team approach. Utilizing preoperative neuroendovascular techniques to occlude shared vascular anastomotic channels, complex total vertical craniopagus twins can now be successfully separated in a one-stage procedure.

A whole-genome shotgun optical map of Yersinia pestis strain KIM.

Yersinia pestis is the causative agent of the bubonic, septicemic, and pneumonic plagues (also known as black death) and has been responsible for recurrent devastating pandemics throughout history. To further understand this virulent bacterium and to accelerate an ongoing sequencing project, two whole-genome restriction maps (XhoI and PvuII) of Y. pestis strain KIM were constructed using shotgun optical mapping. This approach constructs ordered restriction maps from randomly sheared individual DNA molecules directly extracted from cells. The two maps served different purposes; the XhoI map facilitated sequence assembly by providing a scaffold for high-resolution alignment, while the PvuII map verified genome sequence assembly. Our results show that such maps facilitated the closure of sequence gaps and, most importantly, provided a purely independent means for sequence validation. Given the recent advancements to the optical mapping system, increased resolution and throughput are enabling such maps to guide sequence assembly at a very early stage of a microbial sequencing project.