Influence of cartilage and menisci on the sagittal slope of the tibial plateaus

We analyzed the magnetic resonance studies of the knee in 80 subjects, 45 men and 35 women with a mean age of 38.9 years, who showed no pathological condition of the joint. Using an imaging visualization software, the sagittal longitudinal axis of the tibia was identified. The angle between this axis and a line tangent to the bone profile of the tibial plateau (bone slope) and to the superior border of the menisci (meniscal slope) were calculated. Thickness of anterior and posterior portion of menisci and underlying cartilage were also measured. The bone slope averaged 8° and 7.7° on the medial and lateral sides, respectively. The mean meniscal slope was 4.1° and 3.3° on the medial and lateral sides, respectively, with a significant difference compared with the bone slope. Menisci and underlying cartilage were significantly thicker in their posterior than their anterior portion (7.6 and 5.2 mm, respectively, in the medial compartment; 8.6 and 5.2 mm, respectively, in the lateral compartment). The presence of cartilage and menisci implies a significant decrease in the posterior tibial slope. In the lateral compartment, the greater the bone slope, the larger the difference between bone and meniscal slope, which means that a marked posterior tilt of the lateral tibial plateau is decreased by the cartilage and meniscus. These findings should be taken into account in planning surgical procedures which affect the slope of the articular tibial surface. Clin. Anat. 26:883–892, 2013. © 2012 Wiley Periodicals, Inc.     

Development and validation of a method to confirm the exogenous origin of prednisone and prednisolone by GC‐C‐IRMS

Prednisone and prednisolone are two anti‐inflammatory steroidal drugs listed by the World Anti‐Doping Agency (WADA) within the class of glucocorticoids, which are prohibited “in competition” and when administered systemically. Their presence in collected urine samples may be attributed, if no exogenous administration has occurred, to an in situ microbial formation from endogenous steroids. In this work, a gas chromatography coupled to carbon isotope ratio mass spectrometry (GC‐C‐IRMS) method was developed and validated to distinguish an exogenous origin from an endogenous one. Eight prednisone/prednisolone pharmaceutical preparations commercially available in Italy were analysed to establish an exogenous δ¹³C value reference range (?28.96 ± 0.39‰). No more than 25 mL of urine was processed and no derivatization nor intentional steroids structure modifications were performed before the GC‐C‐IRMS analysis. A first HPLC purification step was set up to isolate the three endogenous reference compounds (ERCs) selected (tetrahydro‐11‐deoxycortisol (THS), pregnanediol (PD), and pregnanetriol (PT)), while a second LC purification was necessary to separate prednisone from prednisolone. In the GC‐C‐IRMS analysis, two different GC run methods were set up to guarantee better sensitivity and selectivity for each compound. Both prednisone and prednisolone showed signals (m/z 44) with amplitudes within the method linearity range to a lower urinary concentration of 20 ng/mL (< WADA reporting level, 30 ng/mL). The method was fully validated according to WADA requirements. As a proof of concept, urine samples collected from two excretion studies in healthy male volunteers, after a prednisone or prednisolone administration, were analysed by the proposed method, demonstrating its applicability for the analysis of real samples.     

Modulating Human Procedural Learning by Cerebellar Transcranial Direct Current Stimulation

Neuroimaging studies suggest that the cerebellum contributes to human cognitive processing, particularly procedural learning. This type of learning is often described as implicit learning and involves automatic, associative, and unintentional learning processes. Our aim was to investigate whether cerebellar transcranial direct current stimulation (tDCS) influences procedural learning as measured by the serial reaction time task (SRTT), in which subjects make speeded key press responses to visual cues. A preliminary modeling study demonstrated that our electrode montage (active electrode over the cerebellum with an extra-cephalic reference) generated the maximum electric field amplitude in the cerebellum. We enrolled 21 healthy subjects (aged 20–49 years). Participants did the SRTT, a visual analogue scale and a visual attention task, before and 35 min after receiving 20-min anodal and sham cerebellar tDCS in a randomized order. To avoid carry-over effects, experimental sessions were held at least 1 week apart. For our primary outcome measure (difference in RTs for random and repeated blocks) anodal versus sham tDCS, RTs were significantly slower for sham tDCS than for anodal cerebellar tDCS (p?=?0.04), demonstrating that anodal tDCS influenced implicit learning processes. When we assessed RTs for procedural learning across the one to eight blocks, we found that RTs changed significantly after anodal stimulation (interaction “time”?×?“blocks 1/8”: anodal, p?=?0.006), but after sham tDCS, they remained unchanged (p?=?0.094). No significant changes were found in the other variables assessed. Our finding that anodal cerebellar tDCS improves an implicit learning type essential to the development of several motor skills or cognitive activity suggests that the cerebellum has a critical role in procedural learning. tDCS could be a new tool for improving procedural learning in daily life in healthy subjects and for correcting abnormal learning in neuropsychiatric disorders.     

Pathological gambling in Parkinson's disease: Subthalamic oscillations during economics decisions

Pathological gambling develops in up to 8% of patients with Parkinson's disease. Although the pathophysiology of gambling remains unclear, several findings argue for a dysfunction in the basal ganglia circuits. To clarify the role of the subthalamic nucleus in pathological gambling, we studied its activity during economics decisions. We analyzed local field potentials recorded from deep brain stimulation electrodes in the subthalamic nucleus while parkinsonian patients with (n = 8) and without (n = 9) pathological gambling engaged in an economics decision‐making task comprising conflictual trials (involving possible risk‐taking) and non conflictual trials. In all parkinsonian patients, subthalamic low frequencies (2–12 Hz) increased during economics decisions. Whereas, in patients without gambling, low‐frequency oscillations exhibited a similar pattern during conflictual and non conflictual stimuli, in those with gambling, low‐frequency activity increased significantly more during conflictual than during non conflictual stimuli. The specific low‐frequency oscillatory pattern recorded in patients with Parkinson's disease who gamble could reflect a subthalamic dysfunction that makes their decisional threshold highly sensitive to risky options. When parkinsonian patients process stimuli related to an economics task, low‐frequency subthalamic activity increases. This task‐related change suggests that the cognitive‐affective system that drives economics decisional processes includes the subthalamic nucleus. The specific subthalamic neuronal activity during conflictual decisions in patients with pathological gambling supports the idea that the subthalamic nucleus is involved in behavioral strategies and in the pathophysiology of gambling. © 2013 International Parkinson and Movement Disorder Society     

Radial head,radiocapitellar and total elbow arthroplasties: A review of recent literature

The outcome of prosthetic elbow surgery is continually evolving. We thoroughly reviewed the literature on this issue to analyse the indications, outcomes and complications of the numerous types of implants currently in use. Radial head replacement is recommended in comminuted fractures of the radial head and in post-traumatic conditions. Medium- and long-term results prove to be satisfactory in the majority of cases, with no evidence to indicate that some prostheses (monopolar vs. bipolar; cemented vs. press-fit) are more effective than others; nonetheless, the bipolar-cemented implant was found to be associated with a lower revision rate than other prostheses. Unicompartmental arthroplasty has recently been used for the treatment of osteoarthritis and rheumatoid arthritis when the lateral compartment is prevalently involved; the results reported to date have been encouraging, although further studies are warranted to confirm the validity of these implants. Total elbow arthroplasty is performed in a range of conditions, including distal humerus fractures in the elderly and elbow arthritis. In the former condition, linked elbow replacement yields excellent results with few complications and a low revision rate. In elbow arthritis, total elbow arthroplasty is indicated when patients suffer from disabling pain, stiffness and/or instability that prevent them from performing daily activities. Unlinked elbow arthroplasty, which is used above all in rheumatoid arthritis, also yields satisfactory results, although the risk of instability persists. The use of linked elbow arthroplasty, which yields similar results but lower revision rates, has consequently increased. Lastly, the results yielded by linked elbow prosthesis in post-traumatic conditions are good, although not quite as good as those obtained in rheumatoid arthritis. Early mechanical failure may occur in younger and more active patients after elbow arthroplasty. However, the careful selection of patients who are prepared to accept functional limitations imposed by elbow implants will enable indications for elbow arthroplasty to be extended to young subjects, particularly when no other therapeutic options are available.     

Contralateral recurrent lumbar disc herniation. Results of discectomy compared with those in primary herniation

STUDY DESIGN: The surgical outcomes of patients who underwent discectomy for contralateral recurrent herniation and primary herniation were evaluated. OBJECTIVE: To assess whether the clinical results in patients undergoing surgery for contralateral recurrent disc herniation may be as good as those reported after primary discectomy. SUMMARY OF BACKGROUND DATA: No retrospective or prospective investigation has been conducted on the surgical treatment of contralateral recurrent lumbar disc herniation. METHODS: Sixteen patients who underwent surgery for recurrent disc herniation at the same level as primary disc excision, but on the opposite side, were analyzed prospectively from the recurrence of contralateral radicular pain (Group 1). All patients had reported a satisfactory results after primary discectomy. Fifty consecutive patients who underwent disc excision during the study period, who did not report recurrent radicular pain, were analyzed for comparison (Group 2). Overall patient satisfaction, pain severity, functional outcome, and work status were evaluated. RESULTS: At the 2-year follow-up, the clinical outcome was rated as satisfactory in 14 of 16 patients in Group 1 and in 45 of 50 in Group 2 (P > 0.05). Twelve patients in Group 1 and 42 in Group 2 had resumed their work or daily activities at the same level as before the operation (P > 0.05). Radicular pain was significantly improved in both groups at the 6-month and 2-year follow-ups. At the 6-month follow-up, low back pain was significantly improved only in the patients in Group 2; however, at the 2-year follow-up, low back pain was significantly improved in both groups. CONCLUSIONS: Clinical results in patients reoperated on for contralateral recurrent lumbar disc herniation compare favorably with those reported after primary discectomy. The improvement of pain in the low back and lower limbs reported by the majority of patients 2 years after reoperation suggests that fusion is not needed in this patient population.     

Experimental posterolateral spinal fusion with porous ceramics and mesenchymal stem cells

Alternatives to autogenous bone graft for spinal fusion have been investigated for many years. It has been shown that osteoconductive materials alone do not give a rate of fusion which is comparable to that of autogenous bone graft. We analysed the effectiveness of porous ceramic loaded with cultured mesenchymal stem cells as a new graft material for spinal fusion in an animal model. Posterolateral fusion was carried out at the L4/L5 level in 40 White New Zealand rabbits using one of the following graft materials: porous ceramic granules plus cultured mesenchymal stem cells (group I); ceramic granules plus fresh autogenous bone marrow (group II); ceramic granules alone (group II); and autogenous bone graft (group IV). The animals were killed eight weeks after surgery and the spines were evaluated radiographically, by a manual palpation test and by histological analysis. The rate of fusion was significantly higher in group I compared with group III and higher, but not significantly, in group I compared with groups II and IV. In group I histological analysis showed newly formed bone in contact with the implanted granules and highly cellular bone marrow between the newly formed trabecular bone. In group II, thin trabeculae of newly formed bone were present in the peripheral portion of the fusion mass. In group III, there was a reduced amount of newly formed bone and abundant fibrous tissue. In group IV, there were thin trabeculae of newly formed bone close to the decorticated transverse processes and dead trabecular bone in the central portion of the fusion mass. In vitro cultured mesenchymal stem cells may be loaded into porous ceramic to make a graft material for spinal fusion which appears to be more effective than porous ceramic alone. Further studies are needed to investigate the medium- to long-term results of this procedure, its feasibility in the clinical setting and the most appropriate carrier for mesenchymal stem cells.