The Copeland resurfacing humeral head implant does not restore humeral head anatomy. A retrospective study

Purpose

Recently, there has been concern that the Copeland resurfacing humeral head implant (RHHI) leaves the shoulder joint overstuffed. The purpose of this study was in a selected cohort of patients operated with a Copeland RHHI (1) to evaluate the Length of the Gleno-Humeral Offset (LGHO), (2) to assess the patient-reported quality of life and functional outcome measured by Western Ontario Osteoarthritis of the Shoulder Index (WOOS) and (3) to determine the number of revisions in the cohort.

Methods

Pre- and postoperative radiographs were retrieved from 71 of 91 possible patients operated with a Copeland RHHI from 2005 to 2009. The cohort consisted of 30 males and 41 females at a mean age of 61 (38–89) years. One radiologist measured the LGHO and performed double measurements. The WOOS score 1 year after surgery and the number of revisions from all patients operated with a Copeland RHHI in Denmark was requested from the Danish Shoulder Arthroplasty Registry.

Results

The mean LGHO was 4.99 ± 0.53 cm before surgery and 5.39 ± 0.58 cm after surgery, (p < 0.001). 95 % limits of agreement for measurements of LGHO were ± 0.11 cm. One year after surgery, the WOOS score was 67 for the cohort and 64 for all patients operated with a Copeland RHHI in Denmark. 13 of 71 RHHI in the cohort were revised.

Conclusion

The Copeland RHHI causes significantly increased LGHO and leads to overstuffing in the shoulder joint. The WOOS score in the cohort was comparable to that for all other Danish patients operated with a Copeland RHHI.     

Arthroscopically assisted stabilization of acute high-grade acromioclavicular joint separations in a coracoclavicular Double-TightRope technique: V-shaped versus parallel drill hole orientation

Background

The arthroscopically assisted Double-TightRope technique has recently been reported to yield good to excellent clinical results in the treatment of acute, high-grade acromioclavicular dislocation. However, the orientation of the transclavicular–transcoracoidal drill holes remains a matter of debate.

Hypothesis

A V-shaped drill hole orientation leads to better clinical and radiologic results and provides a higher vertical and horizontal stability compared to parallel drill hole placement.

Study design

This was a cohort study; level of evidence, 2b.

Methods

Two groups of patients with acute high-grade acromioclavicular joint instability (Rockwood type V) were included in this prospective, non-randomized cohort study. 15 patients (1 female/14 male) with a mean age of 37.7 (18–66) years were treated with a Double-TightRope technique using a V-shaped orientation of the drill holes (group 1). 13 patients (1 female/12 male) with a mean age of 40.9 (21–59) years were treated with a Double-TightRope technique with a parallel drill hole placement (group 2). After 2 years, the final evaluation consisted of a complete physical examination of both shoulders, evaluation of the Subjective Shoulder Value (SSV), Constant Score (CS), Taft Score (TF) and Acromioclavicular Joint Instability Score (ACJI) as well as a radiologic examination including bilateral anteroposterior stress views and bilateral Alexander views.

Results

After a mean follow-up of 2 years, all patients were free of shoulder pain at rest and during daily activities. Range of motion did not differ significantly between both groups (p > 0.05). Patients in group 1 reached on average 92.4 points in the CS, 96.2 % in the SSV, 10.5 points in the TF and 75.9 points in the ACJI. Patients in group 2 scored 90.5 points in the CS, 93.9 % in the SSV, 10.5 points in the TF and 84.5 points in the ACJI (p > 0.05). Radiographically, the coracoclavicular distance was found to be 13.9 mm (group 1) and 13.4 mm (group 2) on the affected side and 9.3 mm (group 1) and 9.4 mm (group 2) on the contralateral side. The distance of neither the affected side nor the contralateral side differed significantly between both groups (p > 0.05). In group 1, eight patients (53 %) and in group 2 four patients (31 %) revealed signs of dynamic posterior instability (p > 0.05). Clavicular drill hole enlargement was found to be equally distributed in group 1, whereas group 2 displayed a cone-shaped form.

Conclusion

The Double-TightRope technique yields good to excellent clinical results in both V-shaped and parallel drill hole placement. Partial recurrent vertical and horizontal instability represents a problem in both techniques. So far, no significant differences regarding clinical or radiologic results have been found. Long-term results are needed to reveal possible advantages in terms of clinical and radiologic acromioclavicular stability.     

Reduced plasma membrane surface expression of GLAST mediates decreased glutamate regulation in the aged striatum

Extracellular L-glutamate poses a severe excitotoxic threat to neurons and glia when unregulated, therefore low synaptic levels of this neurotransmitter must be maintained via a rapid and robust transport system. A recent study from our laboratory showed a reduced glutamate uptake rate in the striatum of the aged Fischer 344 (F344) rat, yet the mechanism underlying this phenomenon is unknown. The current study utilized in vivo electrochemical recordings, immunoblotting and biotinylation in young (6 months), late-middle aged (18 months) and aged (24 months) F344 rats to elucidate the potential role that glutamate transporters (GLT-1, GLAST, and EAAC1) may play in this mechanism. Here we show that the time necessary to clear glutamate from the late-middle aged and aged striatum is significantly prolonged in comparison to the young striatum. In addition, an analysis of various sub-regions of the striatum revealed a marked dorsoventral gradient in terms of glutamate clearance times in the aged striatum, a phenomenon which was not present in the striatum of the animals of the remaining age groups. We also found that the decreased glutamate clearance time observed in the late-middle aged and aged rats is not due to a decrease in the production of total transporter protein among these three transporters. Rather, a significant reduction in the amount of GLAST expressed on the plasma membrane surface in the aged animals (approximately 55% when compared to young rats) may contribute to this phenomenon. These age-related alterations in extracellular l-glutamate regulation may be key contributors to the increased susceptibility of the aged brain to excitotoxic insults such as stroke and hypoxia.     

Parent and family factors associated with child adjustment to pediatric cancer

OBJECTIVE: To identify factors that influence the association between parent and child distress among families of children with cancer and comparison peers. METHODS: Parent and child distress, social support, and family environment were assessed among families of 95 children with cancer (94 mothers, 67 fathers) and 98 comparison peers (97 mothers, 77 fathers). RESULTS: Significant associations were found between parent and child distress. For models examining the impact of fathers' distress on children, several moderators were identified (i.e., family environment, child age and gender, a cancer diagnosis, and treatment severity). Family environment also partially mediated father and child distress. CONCLUSIONS: Children whose parents were distressed were more likely to be distressed themselves. Subgroups of children were particularly vulnerable, indicating a need to identify further mechanisms of risk and resilience and to develop family-based interventions. Support was found for including fathers as independent sources of information in pediatric psychology research and clinical practice.     

Relationship between muscle fatty infiltration and the biological characteristics and stimulation potential of tenocytes from rotator cuff tears

The healing after rotator cuff surgery is still dissatisfying, and increased muscle fatty infiltration even more impairs the healing success. To achieve sufficient healing after rotator cuff reconstructions, the use of growth factors may be one possibility. The aim of the study was to identify a possible relationship between fatty infiltration of the supraspinatus muscle and cellular biological characteristics and stimulation potential of tenocyte‐like cells (TLCs). TLCs of 3 donor groups differing in grade of muscle fatty infiltration were analyzed for their cellular characteristics and were stimulated with BMP‐2 or BMP‐7 in a 3D scaffold culture. The cell count and potency for self‐renewal were significantly decreased in TLCs from donors with high muscle fatty infiltration compared to the lower fatty infiltration groups. Cell count and collagen‐I expression as well as protein synthesis were stimulated by growth factors. Interestingly, TLCs of the high fatty infiltration group exhibited a weaker stimulation potential compared to the other groups. TLCs from donors with high muscle fatty infiltration generally revealed inferior characteristics compared to cells of lower fatty infiltration groups, which may be one reason for a weaker healing potential and may represent a possible starting point for the development of future treatment options. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:129–137, 2014.     

Continued anti-VEGF treatment does not prevent recurrences in eyes with stable neovascular age-related macular degeneration using a treat-and-extend regimen: a retrospective case series

BackgroundThe continuation of anti-vascular endothelial growth factor (anti-VEGF) treatment after achieving stability in patients with neovascular age-related macular degeneration has generally been advocated. In our own patients, we thought to assess whether continued anti-VEGF treatment is capable of preventing recurrences.MethodsIn this retrospective observational case series, patients with stable disease either opted to continue treatment every 12–14 weeks (Group 1) or stopped treatment with subsequent follow-up visits every 8–12 weeks (Group 2).ResultsOf the 103 eyes of 103 patients achieving stability, 49 eyes continued treatment (Group 1), whereas treatment was stopped in 54 eyes undergoing regular follow-up (Group 2). Recurrent disease was observed in 21 (42.9%) and 33 (61.1%) cases in Group 1 and Group 2, respectively (p = 0.08). Time between achieving stable disease and recurrence was comparable between Group 1 and Group 2 (11.1 ± 8.2 months vs. 9.2 ± 6.7 months; p = 0.43). The number of visits between achieving stability and disease recurrence was similar, but not the number of injections (3.5 ± 2.0 vs. 0.2 ± 0.4; p < 0.001).ConclusionsContinuing anti-VEGF therapy after achieving functional and morphological stability every 12–14 weeks does not prevent recurrences. Patients deserve to be informed of a potential lifetime risk of recurrences, even under continued therapy.Subject terms: Macular degeneration, Retinal diseases     

Effect of leak around the endotracheal tube on measurements of pulmonary compliance and resistance during mechanical ventilation: A lung model study

We studied the effect of leaks around the endotracheal tube (ETT) on the measurement of pulmonary mechanics during mechanical ventilation. We also evaluated the influence of different ventilator settings on the magnitude of leak. An adjustable leak was created at the end of the ETT in a lung model with constant compliance. Flow, tidal volume, and pressure changes were measured above and below the leak. Compliance (C_i) and resistance (R_i) during inspiration were determined by linear regression analysis (LRA) using the equation of motion and the Mead and Wittenberger method (MWM). The ventilatory change that influenced the degree of leak most was prolongation of inspiratory time (T_i). The presence of a leak around the ETT resulted in an overestimation of the C_i and R_i values, which was proportional to the size of the leak. This overestimation was also influenced by the method used to determine C_i and R_i. Because the contribution of the leak to the tidal volume progressively increased as inspiration continued, methods of analysis that depended mainly on measurement points at the end of inspiration showed a larger deviation from the true C_i and R_i values than methods mainly influenced by measurement points at the beginning of inspiration. Because of this, shortening of inspiration, or analysis of points at the beginning of inspiration reduces the error in the measurements of C_i and R_i when a leak is present. Breaths with a large leak should be excluded from any analysis of pulmonary mechanics. Pediatr Pulmonol. 1996; 22:35–43. © 1996 Wiley-Liss, Inc.     

Alterations in endogenous pain modulation in endurance athletes: An experimental study using quantitative sensory testing and the cold-pressor task

There is evidence for long-term alterations in pain tolerance among athletes compared with normally active controls. However, scientific data on pain thresholds in this population are inconsistent, and the underlying mechanisms for the differences remain unclear. Therefore, we assessed differences and similarities in pain perception and conditioned pain modulation (CPM) at rest in endurance athletes and normally active controls.