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Purpose: To evaluate mid- to long-term clinical outcomes after arthroscopic bucket-handle meniscal tear (BHMT) repair and to assess the impact of concurrent anterior cruciate ligament reconstruction (ACLR)., Methods: A comparative retrospective case series with blinded outcome assessment was conducted. All consecutive patients treated with arthroscopic BHMT repair with or without concurrent ACLR between 2001 and 2021 were eligible for inclusion. Fifty-five patients with an average follow-up of 7.3 ± 3.4 years were included in the analysis. Outcome measures comprised post-operative IKDC Subjective Knee Form, Lysholm Score, Tegner Activity Scale, KOOS, and visual analogue scale (VAS) for satisfaction. Additionally, failure and reoperation rates were assessed., Results: The failure rate was 9%. Medial BHMT repair showed superior post-operative IKDC scores compared to lateral meniscus repair ( p  = 0.038). Concurrent ACLR did not demonstrate any impact on post-operative KOOS, IKDC, Tegner or patient satisfaction. The mean IKDC score at final follow-up across both groups was 80.4 ± 17.8. The mean Lysholm score was 86.9 ± 16.7. Mean KOOS scores were (i) symptoms: 83.6 ± 18.3, (ii) pain: 90.2 ± 14.4, (iii) activities of daily living: 93.6 ± 15.1, (iv) sports: 78.3 ± 26.0 and (v) quality of life: 70.5 ± 24.5. Mean patient satisfaction (VAS) was 7.9 ± 2.5. The mean Tegner score was 4.9 ± 1.9. A consistent positive correlation between the number of sutures used and post-operative outcome measures was observed but did not reach statistical significance for most items., Conclusion: Arthroscopic BHMT repair achieved good clinical outcomes and an acceptable failure rate of 9% at a mean follow-up of 7 years, supporting the clinical value of meniscal repair, including large BHMTs. Concurrent ACLR showed no impact on clinical outcomes., Level of Evidence: Level IV (retrospective case series)., Competing Interests: The authors declare no conflict of interest., (© 2024 The Author(s). Journal of Experimental Orthopaedics published by John Wiley & Sons Ltd on behalf of European Society of Sports Traumatology, Knee Surgery and Arthroscopy.)

Laser plasma-based particle accelerators attract great interest in fields where conventional accelerators reach limits based on size, cost or beam parameters. Despite the fact that particle in cell simulations have predicted several advantageous ion acceleration schemes, laser accelerators have not yet reached their full potential in producing simultaneous high-radiation doses at high particle energies. The most stringent limitation is the lack of a suitable high-repetition rate target that also provides a high degree of control of the plasma conditions required to access these advanced regimes. Here, we demonstrate that the interaction of petawatt-class laser pulses with a pre-formed micrometer-sized cryogenic hydrogen jet plasma overcomes these limitations enabling tailored density scans from the solid to the underdense regime. Our proof-of-concept experiment demonstrates that the near-critical plasma density profile produces proton energies of up to 80 MeV. Based on hydrodynamic and three-dimensional particle in cell simulations, transition between different acceleration schemes are shown, suggesting enhanced proton acceleration at the relativistic transparency front for the optimal case., (© 2023. The Author(s).)

We report on the development of a pump system for ultrafast optical parametric amplifiers (uOPA) as an upgrade for the existing uOPA at the Petawatt High Energy Laser for heavy Ion eXperiments (PHELIX) and the new Petawatt ENergy-Efficient Laser for Optical Plasma Experiments (PEnELOPE). The system consists of a two-stage chirped pulse amplifier, centered around a high energy Yb:YAG regenerative amplifier that delivers 108 mJ uncompressed output energy, resulting in 92 mJ at 1030 nm after compression, pulse durations of 1.4 ps, a high beam quality of M x / y 2 = 1.02 / 1.16 and a relative energy stability of 0.35 %. A second harmonic generation (SHG) efficiency of up to 70 % is achievable and a maximum pulse energy of 43 mJ at 515 nm has been obtained, which is only limited by the damage threshold of the SHG crystal. A self-phase modulation stage makes this system a widely applicable, self-seedable pump module for uOPA without placing strong requirements on its seed oscillator.

Due to the non-linear nature of relativistic laser induced plasma processes, the development of laser-plasma accelerators requires precise numerical modeling. Especially high intensity laser-solid interactions are sensitive to the temporal laser rising edge and the predictive capability of simulations suffers from incomplete information on the plasma state at the onset of the relativistic interaction. Experimental diagnostics utilizing ultra-fast optical backlighters can help to ease this challenge by providing temporally resolved inside into the plasma density evolution. We present the successful implementation of an off-harmonic optical probe laser setup to investigate the interaction of a high-intensity laser at [Formula: see text] peak intensity with a solid-density cylindrical cryogenic hydrogen jet target of [Formula: see text] diameter as a target test bed. The temporal synchronization of pump and probe laser, spectral filtering and spectrally resolved data of the parasitic plasma self-emission are discussed. The probing technique mitigates detector saturation by self-emission and allowed to record a temporal scan of shadowgraphy data revealing details of the target ionization and expansion dynamics that were so far not accessible for the given laser intensity. Plasma expansion speeds of up to [Formula: see text] followed by full target transparency at [Formula: see text] after the high intensity laser peak are observed. A three dimensional particle-in-cell simulation initiated with the diagnosed target pre-expansion at [Formula: see text] and post processed by ray tracing simulations supports the experimental observations and demonstrates the capability of time resolved optical diagnostics to provide quantitative input and feedback to the numerical treatment within the time frame of the relativistic laser-plasma interaction., (© 2022. The Author(s).)

Purpose: To report second-look arthroscopic assessment after all-arthroscopic autologous chondrocyte implantation (ACI) for articular cartilage defects at the patella., Methods: A second-look arthroscopy after all-arthroscopic ACI using chondrospheres ® (ACT3D) was performed in 30 patients with 30 full-thickness retropatellar cartilage defects. The mean time from ACI to second-look arthroscopy was 14.9 ± 16.3 (6-71) months. The quality of cartilage regeneration was evaluated by the International Cartilage-Repair Score (ICRS)-Cartilage Repair Assessment (CRA)., Results: Eleven lesions (36.7%) were classified as CRA grade I (normal) and 19 lesions (63.3%) as grade II (nearly normal). Concerning the degree of defect repair, 25 lesions (83.3%) were repaired up to the height of the surrounding articular retropatellar cartilage. Five lesions (16.7%) showed 75% repair of defect depth. The border zone was completely integrated into the surrounding articular cartilage shoulder in 28 lesions (93.3%) and demarcated within 1 mm in 2 lesions (6.7%). Macroscopically and by probing, 12 lesions (40%) had intact smooth surface, 17 lesions (56.7%) had fibrillated surface and 1 lesion (3.3%) had small, scattered fissures. A negative correlation was found between the overall repair assessment score and the defect size (r 2  = - 0.430, p = 0.046) and between integration into border zone and defect size (r 2  = - 0.340, p = 0.045). A positive correlation was found between macroscopic appearance and age (r 2  =  + 0.384, p = 0.036)., Conclusions: All-arthroscopic ACI using chondrospheres ® (ACT3D) for full-thickness retropatellar articular cartilage defects proved to be reproducible and reliable. The advantage of the procedure is that it is minimal invasive. Arthroscopic second-look demonstrated a high grade of normal or nearly normal cartilage regeneration. Although statistically significant differences were not observed, larger defect size and younger age may compromise the result of overall repair., Level of Evidence: III., (© 2021. European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA).)