Return to sporting activity after Birmingham hip resurfacing arthroplasty: Mid term results

Background:

Hip resurfacing arthroplasty (HRA) is primarily indicated for young, active patients with disabling coxarthrosis who wish to remain active and return to sports after surgery. Relatively few prospective studies have assessed return to sporting activity and impact of gender and age on this.

Materials and Methods:

Seventy-nine consecutive patients treated with HRA were included. Patients were reviewed clinically and radiologically. Function was assessed using the modified University of California Los Angeles (UCLA) activity score. The Oxford, Harris and WOMAC hip scores were calculated.

Results:

Average age at the time of surgery was 54.9 years (range 34.5–73.6 years). Average preoperative and postoperative UCLA scores were 4 and 7.6 respectively. Patients were involved in 2 (0–4) sporting activities preoperatively and 2 (0–5) postoperatively. Preoperative and postoperative Oxford Hip Scores, Harris Hip Score and WOMAC scores were 40, 46 and 51 and 16, 94 and 3 respectively (P < 0.0001). Patients returned to sports at an average of 3 months postoperatively.

Conclusion:

Patients were able to return to sports by 3 months and perform the same number of activities at preoperative intensity. Activity levels are maintained up to the medium term with few complications.     

Expression and function of CD40 on Hodgkin and Reed-Sternberg cells and the possible relevance for Hodgkin's disease

CD40 was originally described as a B-cell-restricted antigen and was subsequently found to be a member of the tumor necrosis factor (TNF) receptor superfamily. CD40 is also expressed on dendritic cells, thymic epithelium, monocytes, and some carcinoma cell lines, and plays a critical role in cell contact-dependent activation. Primary and cultured Hodgkin and Reed-Sternberg (H-RS) cells, the presumed malignant cells of Hodgkin's disease (HD); were found to express high levels of cell surface CD40. We found that recombinant CD40 ligand (CD40L) induced interleukin-8 (IL-8) secretion and enhanced IL-6, TNF, and lymphotoxin-alpha (LT-alpha/TNF-beta) release from cultured H-RS cells. These cytokines play a significant role in the clinical presentation and pathology of HD, a tumor of cytokine-producing cells. CD40L had no mitogenic activity for HD-derived cell lines. In contrast, CD40L enhanced expression of costimulatory molecules intracellular adhesion molecule-T and B7-1 on cultured H-RS cells, both of which are overexpressed on primary H-RS cells. In addition, CD40L induced a 40% to 60% reduction of the expression of the HD-associated CD30 antigen, another member of the TNF receptor superfamily. Primary and cultured H- RS cells express not only CD30, but also CD40. CD40L has pleiotropic biologic activities on H-RS cells, and the CD40-CD40L interaction might be a critical element in the deregulated cytokine network and cell contact-dependent activation cascade typical for HD.     

Biological evaluation of intervertebral disc cells in different formulations of gellan gum‐based hydrogels

Gellan gum (GG)‐based hydrogels are advantageous in tissue engineering not only due to their ability to retain large quantities of water and provide a similar environment to that of natural extracellular matrix (ECM), but also because they can gelify in situ in seconds. Their mechanical properties can be fine‐tuned to mimic natural tissues such as the nucleus pulposus (NP). This study produced different formulations of GG hydrogels by mixing varying amounts of methacrylated (GG‐MA) and high‐acyl gellan gums (HA‐GG) for applications as acellular and cellular NP substitutes. The hydrogels were physicochemically characterized by dynamic mechanical analysis. Degradation and swelling abilities were assessed by soaking in a phosphate buffered saline solution for up to 170 h. Results showed that as HA‐GG content increased, the modulus of the hydrogels decreased. Moreover, increases in HA‐GG content induced greater weight loss in the GG‐MA/HA‐GG formulation compared to GG‐MA hydrogel. Potential cytotoxicity of the hydrogel was assessed by culturing rabbit NP cells up to 7 days. An MTS assay was performed by seeding rabbit NP cells onto the surface of 3D hydrogel disc formulations. Viability of rabbit NP cells encapsulated within the different hydrogel formulations was also evaluated by Calcein‐AM and ATP assays. Results showed that tunable GG‐MA/HA‐GG hydrogels were non‐cytotoxic and supported viability of rabbit NP cells. Copyright © 2012 John Wiley & Sons, Ltd.     

Cervical Spine Motion During Football Equipment-Removal Protocols: A Challenge to the All-or-Nothing Endeavor

Context

The National Athletic Trainers'' Association position statement on acute management of the cervical spine-injured athlete recommended the all-or-nothing endeavor, which involves removing or not removing both helmet and shoulder pads, from equipment-laden American football and ice hockey athletes. However, in supporting research, investigators have not considered alternative protocols.

Objective

To measure cervical spine movement (head relative to sternum) produced when certified athletic trainers (ATs) use the all-or-nothing endeavor and to compare these findings with the movement produced using an alternative pack-and-fill protocol, which involves packing the area under and around the cervical neck and head with rolled towels.

Design

Crossover study.

Setting

Movement analysis laboratory.

Patients or Other Participants

Eight male collegiate football players (age = 21.4 ± 1.4 years; height = 1.87 ± 0.02 m; mass = 103.6 ± 12.5 kg).

Intervention(s)

Four ATs removed equipment under 4 conditions: removal of helmet only followed by placing the head on the ground (H), removal of the helmet only followed by pack-and-fill (HP), removal of the helmet and shoulder pads followed by placing the head on the ground (HS), and removal of the helmet and shoulder pads followed by pack-and-fill (HSP). Motion capture was used to track the movement of the head with respect to the sternum during equipment removal.

Main Outcome Measure(s)

We measured head movement relative to sternum movement (translations and rotations). We used 4 × 4 analyses of variance with repeated measures to compare discrete motion variables (changes in position and total excursions) among protocols and ATs.

Results

Protocol HP resulted in a 0.1 ± 0.6 cm rise in head position compared with a 1.4 ± 0.3 cm drop with protocol HS (P < .001). Protocol HP produced 4.9° less total angular excursion (P < .001) and 2.1 cm less total vertical excursion (P < .001) than protocol HS.

Conclusions

The pack-and-fill protocol was more effective than shoulder pad removal in minimizing cervical spine movement throughout the equipment-removal process. This study provides evidence for including the pack-and-fill protocol in future treatment recommendations when helmet removal is necessary for on-field care.Key Words: National Athletic Trainers'' Association position statement, pack and fill, motion analysis, helmet removal

Key Points

• The pack-and-fill protocol resulted in less overall motion than removal of the helmet and shoulder pads followed by placing the head on the ground, which is currently endorsed by the National Athletic Trainers'' Association.
• Using pack and fill, the athletic trainers could position the head at release in, on average, nearly the identical position as at initiation.
• Removal of the helmet and shoulder pads resulted in a drop in linear and angular head position, placing the cervical spine into increased extension.

American football has the highest number of catastrophic cervical spine injuries of all sports in the United States.¹ Although still of major concern, the incidence of catastrophic cervical spine injuries has declined over the past 35 years, and the rate is now less than 1 per 100 000 exposures.² Much of this decline has been attributed to a 1976 rule change making it illegal to spear, or lower the head to butt or ram an opponent.² Given the force applied at the front and top of a player''s helmet, spearing has long been associated with the axial-load mechanism of injury that results in catastrophic cervical spine injury.³ However, despite a focus on player safety, researchers^4–6 have suggested that the incidence of spearing or other axial head impacts may be as prevalent in American football in the United States today as before the 1976 rule change. Instead, improved prehospital care and on-field management of equipment-laden athletes with potential spine injuries possibly also has led to a reduction in catastrophic cervical spine injuries by reducing the number of cervical spine injuries that result in catastrophic outcomes. This possibility needs to be documented, and research pertaining to prehospital care protocols and management techniques that may affect catastrophic spinal cord injury outcomes in American football needs to continue.Proper prehospital on-field medical care of the athlete with a spine injury, including equipment management, may be critical in limiting secondary cervical spine injury while also allowing access to the airway and chest compressions. The National Athletic Trainers'' Association (NATA) position statement on the acute management of the cervical spine-injured athlete⁷ includes the all-or–nothing technique, which discourages independent removal of the helmet or shoulder pads in American football or ice hockey when an athlete has a potential cervical spine injury. This specific NATA recommendation is based on several studies^8–11 in which the researchers measured vertebral positioning or spinal cord space before and after equipment removal and showed that when the football helmet is removed while the shoulder pads remain in place, cervical alignment can be compromised as the head and neck fall backward into extension.However, a gap exists in the body of evidence used to support this recommendation, as no authors of supporting studies have addressed the use of fillers (eg, rolled towels) to stabilize the head and cervical spine after removing only the helmet and leaving the shoulder pads on the athlete. This technique, termed pack and fill, would fill the void of the missing helmet by placing rolled towels around and beneath the posterior head, cervical spine, and surface of the spine board or ground to prevent the head and cervical spine from moving into extension during performance of critical-care tasks. Although the NATA position statement⁷ mentions this technique as a possibility for an athlete whose helmet is dislodged or shoulder pads are not removed easily, pack and fill could be an alternative clinical practice when removal of the helmet is necessary to provide safe access to the airway (eg, inability to remove the facemask efficiently or a poorly fitted football helmet creating instability of the head and cervical spine within the helmet). Decoster et al¹² recently demonstrated that pack and fill can effectively maintain a neutral sagittal cervical alignment after helmet removal.Another gap in these supporting studies is that they were based on static imaging and, therefore, did not account for the amount of head and neck movement that occurs during the equipment-removal process. In the case of shoulder-pad removal, this could be substantial. Therefore, the purposes of our study were to address these 2 gaps by measuring cervical spine movement (head with respect to sternum) throughout the removal process and to compare this movement among several possible removal protocols. We hypothesized that removal of the helmet combined with the pack-and-fill technique would result in less overall movement than removal of both the helmet and shoulder pads.     

Critical function for the Ras-GTPase activating protein RASA3 in vertebrate erythropoiesis and megakaryopoiesis

Phenotype-driven approaches to gene discovery using inbred mice have been instrumental in identifying genetic determinants of inherited blood dyscrasias. The recessive mutant scat (severe combined anemia and thrombocytopenia) alternates between crisis and remission episodes, indicating an aberrant regulatory feedback mechanism common to erythrocyte and platelet formation. Here, we identify a missense mutation (G125V) in the scat Rasa3 gene, encoding a Ras GTPase activating protein (RasGAP), and elucidate the mechanism producing crisis episodes. The mutation causes mislocalization of RASA3 to the cytosol in scat red cells where it is inactive, leading to increased GTP-bound Ras. Erythropoiesis is severely blocked in scat crisis mice, and ~94% succumb during the second crisis (~30 d of age) from catastrophic hematopoietic failure in the spleen and bone marrow. Megakaryopoiesis is also defective during crisis. Notably, the scat phenotype is recapitulated in zebrafish when rasa3 is silenced. These results highlight a critical, conserved, and nonredundant role for RASA3 in vertebrate hematopoiesis.     

Prediagnostic circulating carotenoid levels and the risk of non-Hodgkin lymphoma: the Multiethnic Cohort

This analysis examined the association of non-Hodgkin lymphoma (NHL) with prediagnostic carotenoid levels, a marker for a diet rich in fruits and vegetables. We conducted a nested case-control study within the Multiethnic Cohort with 271 NHL cases and 538 controls matched on sex, ethnicity, location (Hawaii or Los Angeles), birth year, date and time of blood draw, and hours fasting before blood draw. Serum carotenoid levels were obtained by high-pressure liquid chromatography with photodiode array detection. Conditional logistic regression was used to calculate odds ratios (ORs) according to tertiles of serum carotenoids and trend tests using continuous variables. Higher total serum carotenoids (OR(T3 vs T1) = 0.66 [0.46-0.96]; P(trend) = .02), lycopene (OR = 0.54 [0.38-0.78]; P(trend) = .003), and α-cryptoxanthin (OR = 0.53 [0.36-0.78]; P(trend) = .003) were associated with a lower risk of NHL. For retinol (OR = 0.90 [0.61-1.33]; P(trend) = .04), a statistically significant inverse linear trend was detected. Risk estimates remained unchanged with adjustment for NHL risk factors and were similar in analyses stratified by sex and ethnicity; heterogeneity with NHL subtype was detected only for β-carotene. Other carotenoids, including α-carotene, β-carotene, lutein, β-cryptoxanthin, and zeaxanthin, showed no association with risk. These data provide support for a protective role of carotenoid-rich fruits and vegetables in the etiology of NHL.