Changes in axial alignment of the ipsilateral hip and knee after total hip arthroplasty.

AIMS: We investigated changes in the axial alignment of the ipsilateral hip and knee after total hip arthroplasty (THA). PATIENTS AND METHODS: We reviewed 152 patients undergoing primary THA (163 hips; 22 hips in men, 141 hips in women) without a pre-operative flexion contracture. The mean age was 64 years (30 to 88). The diagnosis was osteoarthritis (OA) in 151 hips (primary in 18 hips, and secondary to dysplasia in 133) and non-OA in 12 hips. A posterolateral approach with repair of the external rotators was used in 134 hips and an anterior approach in 29 hips. We measured changes in leg length and offset on radiographs, and femoral anteversion, internal rotation of the hip and lateral patellar tilt on CT scans, pre- and post-operatively. RESULTS: The mean internal rotation increased by 11° (-15° to 46°) and was associated with underlying disease (OA), pre-operative range of internal rotation, gender, surgical approach, leg lengthening, and change of femoral anteversion (adjusted R(2) : 0.253, p < 0.001). The mean lateral patellar tilt increased by 4° (-5° to 14°) and was associated with age, leg lengthening, and increment of hip internal rotation (adjusted R(2): 0.193, p < 0.001). CONCLUSION: Both internal rotation of the hip at rest and lateral patellar tilt are increased after THA. Changes in rotation after THA may affect gait, daily activities, the rate of dislocation of the hip, and ipsilateral knee pain. TAKE HOME MESSAGE: Internal rotation of the hip at rest and lateral patellar tilt increase after THA.

Significant reduction in the incidence of C5 palsy after cervical laminoplasty using chilled irrigation water.

AIMS: The aim of this study was to determine whether chilled irrigation saline decreases the incidence of clinical upper limb palsy (ULP; a reduction of one grade or more on manual muscle testing; MMT), based on the idea that ULP results from thermal damage to the nerve roots by heat generated by friction during bone drilling. METHODS: Irrigation saline for drilling was used at room temperature (RT, 25.6°C) in open-door laminoplasty in 400 patients (RT group) and chilled to a mean temperature of 12.1°C during operations for 400 patients (low-temperature (LT) group). We assessed deltoid, biceps, and triceps brachii muscle strength by MMT. ULP occurring within two days post-operatively was categorised as early-onset palsy. RESULTS: The incidence of ULP (4.0% vs 9.5%, p = 0.003), especially early-onset palsy (1.0% vs 5.5%, p < 0.001), was significantly lower for the LT group than for the RT group. Multivariate analysis indicated that RT irrigation saline use, concomitant foraminotomy, and opened side were significant predictors for ULP. DISCUSSION: Using chilled irrigation saline during bone drilling significantly decreased the ULP incidence, particularly the early-onset type, and shortened the recovery period for ULP. Chilled irrigation saline can thus be recommended as a simple method for preventing ULP. TAKE HOME MESSAGE: Chilled irrigation during laminoplasty reduces C5 palsy.

Eight-year preservation of knee function with radiographic healing phenomena after anti-tumor necrosis factor-α therapy for a severely erosive knee in a young patient with rheumatoid arthritis.

A 23-year-old woman developed rheumatoid arthritis (RA). The pain in her right knee was aggravated and anti-tumor necrosis factor (TNF)-α therapy was selected at the age of 35. The range of motion and Larsen grade were 5º to 120º and 4, respectively. Infliximab and etanercept therapies were quite effective and the pain of the right knee improved. An X-ray at 1 year showed radiographic healing phenomena that included reappearance of a clear visible cortical plane, partial filling-in of erosions and cysts, and sclerosis of the subchondral bone. An X-ray at the age of 43 showed that the radiographic healing phenomena were still preserved after 7 years. The right knee remained pain-free although the Larsen grade was still 4, and the knee function was preserved for 8 years. In conclusion, anti-TNF-α therapy may preserve knee function with radiographic healing phenomena and prevent total arthroplasty of severely erosive knees in young RA patients.

Safety and efficacy of edoxaban, an oral factor xa inhibitor, for thromboprophylaxis after total hip arthroplasty in Japan and Taiwan.

Edoxaban, an oral direct factor Xa inhibitor, has proven antithrombotic efficacy. In a multicenter, phase II study, 264 total hip arthroplasty (THA) patients randomly received edoxaban 15 or 30 mg once daily or enoxaparin 2000IU (20-mg) twice daily for 11-14 days. Thromboembolic event incidences were 3.8% (3/78), 2.8% (2/72), and 4.1% (3/74) for edoxaban 15-mg, 30-mg, and enoxaparin, respectively (P=1.00). Edoxaban-induced prolongation of prothrombin time, international normalized ratio, and activated partial thromboplastin time were proportional to plasma edoxaban concentration. Major or clinically relevant non-major bleeding incidences were 2.2% (2/89), 1.2% (1/85), and 2.3% (2/87) for edoxaban 15-mg, 30-mg, and enoxaparin, respectively (P=1.00). Once-daily edoxaban showed similar efficacy and safety to enoxaparin for prevention of thromboembolic events in patients undergoing THA.

Single-shot detection of mid-infrared spectra by chirped-pulse upconversion with four-wave difference frequency generation in gases.

Single-shot detection of ultrabroadband mid-infrared spectra was demonstrated by using chirped-pulse upconversion technique with four-wave difference frequency generation in gases. Thanks to the low dispersion of the gas media, the bandwidth of the phase matching condition of the upconversion process becomes very broad and the entire mid-infrared spectrum spanning from 200 to 5500 cm(-1) was upconverted by using a 10 ps chirped pulse to visible wavelength radiation, which was detected with a conventional visible dispersive spectrometer. This method was demonstrated by the successful measurement of infrared absorption spectra of organic polymer films.

Migration ecology of juvenile temperate seabass Lateolabrax japonicus: a carbon stable-isotope approach.

The migration pattern of juvenile temperate seabass Lateolabrax japonicus in the stratified estuary of the Yura River was examined using carbon stable-isotope ratios (δ(13)C). δ(13)C values of mysids, which are the most important prey items for this species, were consistently enriched in the lower estuary and surf zone (LES), while depleted in the freshwater zone (FW). δ(13)C values of juveniles in LES were enriched, while those in FW were depleted, consistent with the δ(13)C difference in prey items. The results of δ(13)C showed that many juveniles migrated upstream from April to June and most of them stayed in FW until at least July. Juveniles that stayed in FW and LES for a relatively longer period (> c. 20 days) showed higher condition factors than those that stayed in FW for a short period (several days). This indicates that residence in FW enabled juveniles to achieve as good a body condition as residence in LES.

Observation of few-cycle, strong-field phenomena in surface plasmon fields.

We present experimental evidence of the generation of few-cycle propagating surface plasmon polariton wavepackets. These ultrashort plasmonic pulses comprised of only 2-3 field oscillations were characterized by an autocorrelation measurement based on electron photoemission. By exploiting plasmonic field enhancement, we achieved plasmon-induced tunnelling emission from the metal surface at low laser intensity, opening perspectives for strong-field experiments with low pulse energies. All-optical electron acceleration up to keV kinetic energy is also demonstrated in these surface-confined, few-cycle fields with only 1.35×10(12) W/cm2 focused laser intensity. The experimental results are found to be in excellent agreement with the model.

A dose-ranging study evaluating the oral factor Xa inhibitor edoxaban for the prevention of venous thromboembolism in patients undergoing total knee arthroplasty.

BACKGROUND: Edoxaban (the free base of DU-176b) is an oral, direct factor (F)Xa inhibitor in clinical development for the prevention and treatment of thromboembolic events. OBJECTIVES: The aim of the present study was to evaluate the efficacy and safety of edoxaban for the prevention of venous thromboembolism (VTE) in patients undergoing total knee arthroplasty (TKA). PATIENTS/METHODS: This was a randomized, double-blind, placebo-controlled, multicenter study conducted in Japan. A total of 523 Japanese patients were assigned to receive edoxaban 5, 15, 30 or 60 mg once daily or placebo for 11-14 days. A placebo control was used as neither low-molecular-weight heparin (LMWH) nor fondaparinux had been approved for thromboprophylaxis at the time of the study in Japan. The primary efficacy outcome was the incidence of VTE (lower-extremity deep vein thrombosis, symptomatic pulmonary embolism or symptomatic deep vein thrombosis). The primary safety outcome was the incidence of major and clinically relevant non-major bleeding. RESULTS: Edoxaban produced a significant dose-related reduction in VTE: the incidence of VTE was 29.5%, 26.1%, 12.5% and 9.1% in the edoxaban 5-, 15-, 30- and 60-mg treatment groups vs. 48.3% in the placebo group. The incidence of major and clinically relevant non-major bleeding was similar across all groups without any significant differences among edoxaban doses or between edoxaban and placebo. CONCLUSIONS: Edoxaban demonstrated significant dose-dependent reductions in VTE in patients undergoing TKA with a bleeding incidence similar to placebo. [This trial is registered with JAPIC, JapicCTI-060283 (ja).].

Spectral phase transfer to ultrashort UV pulses through four-wave mixing.

Transfer of spectral phase from near infrared ultrashort pulses to deep ultraviolet (UV) sub-30-fs pulses through four-wave mixing process is demonstrated. Micro joule UV pulses at 237 nm were generated by nonlinear mixing of second harmonic pulses of Ti:sapphire laser output and near infrared pulses from a noncollinear optical parametric amplifier. Chirp of the near infrared pulse was transferred to the UV pulse with the opposite sign. A positively chirped near infrared pulse was used for generating a negatively chirped UV pulse, which was compressed down to 25 fs by a magnesium fluoride window.

Potential risk of thermal damage to cervical nerve roots by a high-speed drill.

Using the transverse processes of fresh porcine lumbar spines as an experimental model we evaluated the heat generated by a rotating burr of a high-speed drill in cutting the bone. The temperature at the drilled site reached 174 degrees C with a diamond burr and 77 degrees C with a steel burr. With water irrigation at a flow rate of 540 ml/hr an effective reduction in the temperature was achieved whereas irrigation with water at 180 ml/hr was much less effective. There was a significant negative correlation between the thickness of the residual bone and the temperature measured at its undersurface adjacent to the drilling site (p < 0.001). Our data suggest that tissues neighbouring the drilled bone, especially nerve roots, can be damaged by the heat generated from the tip of a high-speed drill. Nerve-root palsy, one of the most common complications of cervical spinal surgery, may be caused by thermal damage to nerve roots arising in this manner.

Laminoplasty for patients aged 75 years or older with cervical myelopathy.

PURPOSE: To assess the neurological and walking status of 56 elderly patients after cervical myelopathy to determine whether the surgery was justified. METHODS: Records of 23 men and 33 women aged 75 to 86 (mean, 79) years who underwent laminoplasty for cervical myelopathy were retrospectively reviewed. They had been followed up for a mean of 3.5 (range, 0.2-8.6) years. Walking status was assessed according to long-term care insurance criteria. In 45 patients with more than 2 years of follow-up, neurological status was evaluated according to the Japanese Orthopaedic Association (JOA) score. Neurological recovery rate was classified as excellent, good, fair, poor, and worse. RESULTS: Postoperatively, of the 47 patients still living, 22 could walk independently, 22 required assistance outdoors, 2 were using a wheelchair, and one was bedridden. The mean JOA score was 9.7 preoperatively, 12.2 one year postoperatively, and 11.8 at final assessment (p<0.001). The mean neurological recovery rate was 29% at one-year follow-up and 24% at final assessment (p=0.06). CONCLUSION: Although excellent results were not expected in elderly patients, surgery to maintain independent walking status was justified in most of our patients.

The post-operative changes in the level of inflammatory markers after posterior lumbar interbody fusion.

Inflammatory markers such as the C-reactive protein (CRP), white blood cell count and body temperature are easy to measure and are used as indicators of infection. The way in which they change in the early post-operative period after instrumented spinal surgery has not been reported in any depth. We measured these markers pre-operatively and at one, four, seven and 14 days postoperatively in 143 patients who had undergone an instrumented posterior lumbar interbody fusion. The CRP proved to be the only sensitive marker and had returned to its normal level in 48% of patients after 14 days. The CRP on day 7 was never higher than that on day 4. Age, gender, body temperature, operating time and blood loss were not related to the CRP level. A high CRP does not in itself suggest infection, but any increase after four days may presage infection.

Risedronate reduces postoperative bone resorption after cementless total hip arthroplasty.

UNLABELLED: Forty-three patients who had undergone cementless THA were randomly assigned to receive no osteoactive drug or oral risedronate for 6 months. Postoperative decrease of BMD in the risedronate group was significantly lower than that seen in the control group in zones 1, 2, 3, 6, and 7. INTRODUCTION: Proximal bone resorption around the femoral stem often has been observed after total hip arthroplasty (THA), could lead to late stem loosening. We previously reported the efficacy of etidronate on periprosthetic bone resorption after cementless THA. Recently risedronate is suggested to be effective for the prevention and treatment of for osteoporosis. The purpose of the present study was to evaluate the effects of risedronate on periprosthetic bone loss after cementless THA. METHODS: Forty-three patients who had undergone cementless THA were randomly assigned to receive no osteoactive drug (21 patients) or oral risedronate 2.5 mg/day (22 patients) for 6 months. Three patients were eliminated from the risedronate group because of dyspepsia. Periprosthetic bone mineral density (BMD) in seven regions of interest based on the zones of Gruen et al. was measured with dual energy X-ray absorptiometry at 3 weeks and 6 months postoperatively. RESULTS: At 6 months after surgery, postoperative decrease of BMD in the risedronate group was significantly lower than that seen in the control group in zones 1, 2, 3, 6, and 7 (p < 0.05, p < 0.01, p < 0.01, p < 0.05, and p < 0.05, respectively). CONCLUSION: These outcomes suggested that risedronate might reduce the periprosthetic bone resorption after cementless THA.

Widely tunable soliton frequency shifting of few-cycle laser pulses.

Photonic-crystal fibers are employed to demonstrate widely tunable frequency down-conversion of unamplified 6-fs Ti:sapphire laser pulses through the soliton self-frequency shift induced by the Raman effect. Wavelength shifts as large as 500 nm are achieved for input few-cycle pulses with broadband spectra centered at approximately 820 nm. The central wavelength of the redshifted output of a photonic-crystal fiber is smoothly tuned from the low-frequency edge in the spectrum of the 6-fs Ti:sapphire laser pulse up to 1.35 microm by varying the input energy in the fundamental mode of the fiber.

Diffraction-arrested soliton self-frequency shift of few-cycle laser pulses in a photonic-crystal fiber.

The balance between diffraction and index-step guiding in photonic-crystal fibers is controlled by modifying the fiber structure, leading to different wavelength dependences of the effective mode area and providing a mechanism to control nonlinear-optical phenomena. In optical fibers with a steep profile, the guided mode of the light field tends to become much less compact with an increase in radiation wavelength, slowing down the Raman-induced soliton self-frequency shift of an ultrashort laser pulse. A reduction of the soliton self-frequency shift is demonstrated for input laser pulses.

Parametric amplification of few-cycle carrier-envelope phase-stable pulses at 2.1 microm.

We demonstrate an optical parametric chirped-pulse amplifier producing infrared 20 fs (3-optical-cycle) pulses with a stable carrier-envelope phase. The amplifier is seeded with self-phase-stabilized pulses obtained by optical rectification of the output of an ultrabroadband Ti:sapphire oscillator. Energies of -80 microJ with a well-suppressed background of parametric superfluorescence and up to 400 microJ with a superfluorescence background are obtained from a two-stage parametric amplifier based on periodically poled LiNbO3 and LiTaO3 crystals. The parametric amplifier is pumped by an optically synchronized 1 kHz, 30 ps, 1053 nm Nd:YLF amplifier seeded by the same Ti:sapphire oscillator.

Nonlinear-optical spectral transformation of few-cycle laser pulses in photonic-crystal fibers.

Photonic-crystal fibers with special dispersion profiles are shown to provide a high efficiency of spectral transformation of chirped sub-6-fs Ti:sapphire laser pulses. With the wavelength of zero group-velocity dispersion of the fiber lying within the broad spectrum of the input few-cycle pulse, the output spectra feature well-resolved spectral peaks, indicative of soliton self-frequency shift, four-wave mixing, and Cherenkov emission of dispersive waves. We demonstrate that up to 3% of radiation energy at the output of the fiber can be confined within a spectrally isolated soliton peak centered at , which is ideally suited as a seed for Nd:YAG- and ytterbium-based laser devices.

Multimillijoule chirped parametric amplification of few-cycle pulses.

The concept of optical parametric chirped-pulse amplification is applied to attain pulses with energies up to 8 mJ and a bandwidth of more than 100 THz. Stretched broadband seed pulses from a Ti:sapphire oscillator are amplified in a multistage noncollinear type I phase-matched beta-barium borate parametric amplifier by use of an independent picosecond laser with lock-to-clock repetition rate synchronization. Partial compression of amplified pulses is demonstrated down to a 10-fs duration with a down-chirped pulse stretcher and a nearly lossless compressor comprising bulk material and positive-dispersion chirped mirrors.

Soliton-based pump-seed synchronization for few-cycle OPCPA.

We demonstrate a significant simplification of the scheme for few-cycle Optical Parametric Chirped Pulse Amplification (OPCPA) which results in the elimination of a picosecond's master oscillator and electronic synchronization loops. A fraction of a broadband seed pulse centered at 760 nm from a 70-MHz Ti:sapphire oscillator was frequency-shifted in a photonic crystal fiber to enable synchronized seeding of a picosecond's Nd:YAG pump laser. The seed radiation at 1064 nm is produced in the soliton regime which makes it inherently more intense and stable in comparison with other methods of frequency conversion. The remaining fraction of the Ti:sapphire output is amplified with a FWHM bandwidth of 250 nm in a single timing-jitter-free OPCPA stage. Our work opens up the exciting possibility to use sub-picosecond's pump pulses from highly efficient Yb-based amplifiers for jitter-less parametric amplification of carrier-envelope phase stabilized pulses from Ti:sapphire oscillators.

Pulse compression with time-domain optimized chirped mirrors.

Dispersive optical interference coatings (chirped mirrors - CMs) are designed by computer optimization of an analytically calculated initial multilayer. Traditionally, the relevant properties of the CM (reflectance and the frequency-dependence of the phase shift upon reflection) are optimized to match frequency-domain targets. We propose a novel target function that quantifies directly the capability of a multilayer to control the temporal shape of the reflected optical pulse. Employing this time-domain analysis/optimization one can design dispersive multilayers having air as medium of incidence and supporting the generation of pulses with durations in the sub-5-fs-range, as demonstrated in a proof-of-principle compression experiment.