Ultrafast Infrared Laser Crystallization of Amorphous Si/Ge Multilayer Structures.

Silicon-germanium multilayer structures consisting of alternating Si and Ge amorphous nanolayers were annealed by ultrashort laser pulses at near-infrared (1030 nm) and mid-infrared (1500 nm) wavelengths. In this paper, we investigate the effects of the type of substrate (Si or glass), and the number of laser pulses (single-shot and multi-shot regimes) on the crystallization of the layers. Based on structural Raman spectroscopy analysis, several annealing regimes were revealed depending on laser fluence, including partial or complete crystallization of the components and formation of solid Si-Ge alloys. Conditions for selective crystallization of germanium when Si remains amorphous and there is no intermixing between the Si and Ge layers were found. Femtosecond mid-IR laser annealing appeared to be particularly favorable for such selective crystallization. Similar crystallization regimes were observed for both single-shot and multi-shot conditions, although at lower fluences and with a lower selectivity in the latter case. A theoretical analysis was carried out based on the laser energy absorption mechanisms, thermal stresses, and non-thermal effects.

Highly Regular LIPSS on Thin Molybdenum Films: Optimization and Generic Criteria.

A systematic experimental study was performed to determine laser irradiation conditions for the large-area fabrication of highly regular laser-induced periodic surface structures (HR-LIPSS) on a 220 nm thick Mo film deposited on fused silica. The LIPSS were fabricated by scanning a linearly polarized, spatially Gaussian laser beam at 1030 nm wavelength and 1.4 ps pulse duration over the sample surface at 1 kHz repetition rate. Scanning electron microscope images of the produced structures were analyzed using the criterion of the dispersion of the LIPSS orientation angle (DLOA). Favorable conditions, in terms of laser fluence and beam scanning overlaps, were identified for achieving DLOA values <10∘. To gain insight into the material behavior under these irradiation conditions, a theoretical analysis of the film heating was performed, and surface plasmon polariton excitation is discussed. A possible effect of the film dewetting from the dielectric substrate is deliberated.

Anterior Cruciate Ligament Reconstruction Using Bone-Patella Tendon-Bone Autograft With Press-Fit Femoral Fixation: The Original Chambat Technique.

Patellar tendon grafts have long been considered the gold standard for anterior cruciate ligament reconstruction (ACLR). This Technical Note describes ACLR using bone-patella tendon-bone (BPTB) autograft with press-fit femoral fixation using an outside-in drilling technique.

All-Arthroscopic Treatment of Combined Posterior Cruciate Ligament and Posterolateral Corner Instability.

Injuries to the posterolateral corner (PLC) of the knee are uncommon, and usually associated with other ligamentous injuries. A combined posterior cruciate ligament (PCL) and PLC tear is the most frequent combination. Several studies describe anatomic reconstructive techniques using an open approach with large incisions and extensive exploration of the posterolateral structures. This Technical Note describes an all-arthroscopic technique as a safe and efficient treatment of combined PCL and PLC instability using the trans-septal approach.

Suture Hook Versus All-Inside Repair for Longitudinal Tears of the Posterior Horn of the Medial Meniscus Concomitant to Anterior Cruciate Ligament Reconstruction: A Matched-Pair Analysis From the SANTI Study Group.

BACKGROUND: Secondary meniscectomy rates after repair of longitudinal tears of the posterior horn of the medial meniscus (PHMM) performed concomitantly with anterior cruciate ligament reconstruction (ACLR) are reported to be as high as 25% with an all inside repair technique. Posteromedial portal suture hook repair is an emerging technique; however, it is unknown whether it confers a significantly reduced secondary meniscectomy rate compared with the current gold standard. PURPOSE/HYPOTHESIS: The primary objective of this study was to compare the secondary meniscectomy rates of suture hook repair and all inside repair for longitudinal tears of the PHMM performed concomitant to ACLR. The secondary outcome was to determine the risk factors associated with the failure of the repair. It was hypothesized that repair with an all inside device would be associated with higher secondary meniscectomy rates when compared with suture hook repair and that concomitant anterolateral ligament reconstruction (ALLR) would confer improved meniscal repair survivorship. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Patients with longitudinal tears of the PHMM who underwent meniscal repair during primary ACLR between January 2011 and December 2015 at our institution were eligible for the study. Patients undergoing suture hook repair were propensity matched in a 1:1 ratio to patients who underwent all inside repair. At the end of the study period, secondary meniscectomy rates were determined. RESULTS: The study population comprised 237 matched pairs. The mean follow up was 97.7 ± 17.3 months. Patients who underwent an all inside repair had a >2-fold higher failure rate compared with patients who underwent suture hook repair through a posteromedial portal (31.2% vs 15.6%; P = .0003). Patients in the suture hook repair group undergoing additional ALLR demonstrated a >3-fold higher meniscal repair survival rate compared with all other subgroups (P = .0014). This association was not seen in the all inside repair group. The only statistically significant risk factor for meniscal repair failure was the suture repair technique (hazard ratio, 2.133 [95% CI, 1.383-3.292]; P = .0008). CONCLUSION: Suture hook repair through a posteromedial portal is associated with a significantly lower secondary meniscectomy rate when compared with the all inside meniscal repair of longitudinal tears of the PHMM performed at the time of ACLR. Furthermore, patients in the suture hook repair group who underwent an additional ALLR had a significantly better meniscal repair survivorship compared with all other subgroups.

Same-day bilateral total knee replacement versus unilateral total knee replacement: A comparative study.

INTRODUCTION: Bilateral total knee arthroplasty (TKA) in a single session is rarely done in France, mainly due to the increased risk of perioperative and late complications. The primary objective of this study was to compare the complication rates of same-day bilateral TKA (TKA bilat) with that of unilateral TKA (TKA unilat). The hypothesis was bilateral TKA increases the rate of early and late complications in a group of selected patients (ASA 1 or 2, less than 80 years of age). MATERIAL AND METHODS: Retrospective comparative study of 91 bilat TKA and 182 unilat TKA cases operated on between 2009 and 2016 (1 bilat TKA paired with 2 controls). The patients were matched based on age, sex, indication and ASA score. The minimum follow-up was 2 years. Mortality along with early and late complications were documented. The secondary endpoints were implant survival, functional outcomes, and patient satisfaction. RESULTS: The early mortality rate was zero in both groups. The early complication rate was lower in the bilat TKA group (9%) than in the unilat TKA group (22%) (p<0.001). The late complications did not differ between groups. Implant survival at 5 years was 99% (95% CI=[95.6-99.7]) in the bilat TKA group and 97% (95% CI=[92.8-98.8]) in the unilat TKA group. The autologous blood transfusion rate was 33% in the bilat TKA group and 2.2% in the unilat TKA group (p<0.001). There was no difference between groups in the satisfaction rate or the KOOS and New IKS scores. A larger share of patients in the unilat TKA group (54%) said they had forgotten about their knee than in the bilat TKA group (43%) (p=0.036). DISCUSSION: There were few early complications in the bilat TKA group. There was no significant difference in the number of late complications, survival, functional scores, or patient satisfaction between the two groups. The transfusion rate was higher in the bilat TKA group, while the forgotten knee rate was higher in the unilat TKA group. CONCLUSION: Our hypothesis was not confirmed: in the context of this study, in patients who are ASA 1 or 2, and less than 80 years old, same-day bilateral TKA does not increase the complication rate relative to unilateral TKA. LEVEL OF EVIDENCE: III, comparative study of continuous paired cases.

How to Avoid Iatrogenic Saphenous Nerve Injury During Outside-In or Inside-Out Medial Meniscus Sutures.

Medial meniscal sutures using outside-in or inside-out techniques are very popular. Nevertheless, a saphenous nerve entrapment may occur with these techniques. This Technical Note describes a modified outside-in medial meniscus suture without any additional skin incisions. By dissecting the space between the subcutaneous and the capsule, which is performed by grasping and knotting the sutures through the anteromedial portal, iatrogenic saphenous nerve injury is avoided.

Prevention of surgical site infections in pediatric spines: a single-center experience.

PURPOSE: To describe the potential issues in the methodology of surgical site infection (SSI) prevention and how it was investigated and corrected in a single institution. METHODS: A pediatric orthopedic unit experienced an increase of SSI, concerning up to 10% of scoliosis surgery cases from 2011 to 2013. An institutional procedure of multimodal and interdisciplinary risk evaluation was initiated, including a review of the literature, a morbi-mortality meeting, internal and external audits concerning the hygiene conditions in the operating room, the antibiotic prophylaxis, patients, and sterile material pathways. Several preventive actions were implemented, including the improvement of air treatment in the operating room, wound irrigation with 2L of saline before closure, application of topic vancomycine in the wound, verification of doses and timing of antibiotics injection, and use of waterproof bandages. We compared the rates of spine SSI before (retrospective group, 2011-2013) and after the implementation of various preventive measures (prospective group, 2014-2018). RESULTS: SSI occurred in 12 patients (6 idiopathic and 6 neuromuscular) out of 120 operated on (93 idiopathic, 18 neuromuscular, 9 others) in the retrospective group and 2 (both neuromuscular) out of 196 (150 idiopathic, 33 neuromuscular,13 others) in the prospective group (10% vs 1%, odds ratio=9.7, p=0.001). The groups were comparable for age, etiology, duration of surgery, body mass index, American Society of Anesthesiologists score, number of levels fused, and blood loss (p>0.2). CONCLUSION: The systematic analysis of SSI allowed for the understanding of the failures and correcting them. The current process is effectively preventing SSI. LEVEL OF EVIDENCE: 3: prospective series with case-control analysis.

Three-Step Description of Single-Pulse Formation of Laser-Induced Periodic Surface Structures on Metals.

Two different scenarios are usually invoked in the formation of femtosecond Laser-Induced Periodic Surface Structures (LIPSS), either "self-organization" mechanisms or a purely "plasmonic" approach. In this paper, a three-step model of formation of single-laser-shot LIPSS is summarized. It is based on the periodic perturbation of the electronic temperature followed by an amplification, for given spatial periods, of the modulation in the lattice temperature and a final possible relocation by hydrodynamic instabilities. An analytical theory of the evolution of the temperature inhomogeneities is reported and supported by numerical calculations on the examples of three different metals: Al, Au, and Mo. The criteria of the possibility of hydrodynamic instabilities are also discussed.

One-session bilateral total knee replacement: Late complications and survivorship.

INTRODUCTION: The early morbidity and mortality of one-session bilateral total knee arthroplasty (1-session BTKA) has been reported in the medical literature. However, there is less information about the long-term clinical impact of this strategy. The aim of this study was to report on the late complications (>90 days), clinical outcomes (KOOS and new KSS) along with the survivorship of 1-session BTKA. We hypothesised that 1-session BTKA will cause few late complications and that the implant survival will meet the criteria of the National Institute for Health and Clinical Excellence (NICE). METHODS: This single-centre retrospective study analysed a cohort of ASA-1 and ASA-2 patients who underwent 1-session BTKR over an 8-year period (2009 to 2016). The cohort consisted of 116 patients (66% women, 34% men) with mean age at inclusion of 69 years (32-85 years); 22% of patients were ASA-1 and 78% were ASA-2. The implant-related, infection-related or mechanical complications that occurred more than 90 days after the operation, the clinical outcomes (KOOS and New KSS) and radiological outcomes, along with the survivorship were determined during the scheduled follow-up visits at 3 months, 6 months and 1 year postoperative and during the long-term follow-up or during an intercurrent event. RESULTS: No patients were lost to follow-up. Fifteen complications occurred (6.5%): four infections, four patellar problems (three cases of clunk syndrome and one of patellofemoral pain), four cases of stiffness, two of unexplained pain and one femoral periprosthetic fracture. Eight patients were readmitted to the hospital (7%); seven were reoperated (3%) and two implants were revised (1%). The functional outcomes (KOOS and New KSS) were significantly improved and 87% of patients were satisfied or very satisfied with this procedure. At a mean follow-up of 5 years, the survivorship estimated using the Kaplan-Meier method was 98.4% (95% CI: 0.933-0.996). CONCLUSION: Performing 1-session BTKA is a reliable strategy as it produces a low rate of late complications, excellent medium-term functional outcomes and survivorship that meets NICE criteria, thus confirming our hypothesis. LEVEL OF EVIDENCE: IV, retrospective case series.

Early morbidity and mortality after single-stage bilateral total knee replacement.

INTRODUCTION: Single-stage bilateral total knee replacement (TKR) has the advantages of requiring only one hospital stay and one anesthesia session, having a shorter rehabilitation period, and reducing the cost of patient care. However, this strategy is controversial because of the perioperative risk. We hypothesized that this strategy did not cause early perioperative mortality and that the early morbidity and readmission rates would be low when patients are selected based on their ASA score. METHODS: This single-center retrospective study analyzed a cohort of ASA-1 and ASA-2 patients who underwent single-stage bilateral TKR over an 8-year period (2009 to 2016). The study cohort consisted of 116 patients, mainly women with mean age of 69 years at inclusion; 22.4% of patients were ASA-1 and 77.6% were ASA-2. Death and early complications during the first 90 days postoperative, the early readmission rate and the blood-sparing strategy were analyzed using the clinical and paraclinical data collected during the hospital stay, during the convalescent care center stay, and during the follow-up visits at 6 weeks and 3 months postoperative. The analysis was completed using the intrahospital software Clinicom, which allowed us to trace all the events and episodes for each patient. RESULTS: The early mortality rate was 0%. There were five major complications (4.3%) and thirteen minor complications (11%). The early readmission rate was 5.2%. Homologous blood transfusion was performed in 36% of patients. Administration of tranexamic acid reduced this rate to 24.3% versus 44% in patients not taking it (p=0.06). CONCLUSION: The perioperative mortality in this selected population is zero and the early morbidity is acceptable. The early readmission rate is also low. Thus proposing single-stage bilateral TKR to patients meeting the criteria defined in this study is a valid strategy. LEVEL OF EVIDENCE: IV, retrospective cohort study.

High-speed manufacturing of highly regular femtosecond laser-induced periodic surface structures: physical origin of regularity.

Highly regular laser-induced periodic surface structures (HR-LIPSS) have been fabricated on surfaces of Mo, steel alloy and Ti at a record processing speed on large areas and with a record regularity in the obtained sub-wavelength structures. The physical mechanisms governing LIPSS regularity are identified and linked with the decay length (i.e. the mean free path) of the excited surface electromagnetic waves (SEWs). The dispersion of the LIPSS orientation angle well correlates with the SEWs decay length: the shorter this length, the more regular are the LIPSS. A material dependent criterion for obtaining HR-LIPSS is proposed for a large variety of metallic materials. It has been found that decreasing the spot size close to the SEW decay length is a key for covering several cm2 of material surface by HR-LIPSS in a few seconds. Theoretical predictions suggest that reducing the laser wavelength can provide the possibility of HR-LIPSS production on principally any metal. This new achievement in the unprecedented level of control over the laser-induced periodic structure formation makes this laser-writing technology to be flexible, robust and, hence, highly competitive for advanced industrial applications based on surface nanostructuring.