Vitamin E-enriched medium cross-linked polyethylene in total knee arthroplasty (VIKEP): clinical outcome, oxidation profile, and wear analysis in comparison to standard polyethylene-study protocol for a randomized controlled trial.

BACKGROUND: The gliding surface of total knee endoprostheses is exposed to high loads due to patient weight and activity. These implant components are typically manufactured from ultra-high molecular weight polyethylene (UHMWPE). Crosslinking of UHMWPE by ionizing radiation results in higher wear resistance but induces the formation of free radicals which impair mechanical properties after contact with oxygen. Medium-crosslinked UHMWPE enriched with vitamin E (MXE) provides a balance between the parameters for a sustainable gliding surface, i.e., mechanical strength, wear resistance, particle size, and oxidation stability. Therefore, a gliding surface for knee endoprostheses made up from this material was developed, certified, and launched. The aim of this study is to compare this new gliding surface to the established predecessor in a non-inferiority design. METHODS: This multicenter, binational randomized controlled trial will enroll patients with knee osteoarthritis eligible for knee arthroplasty with the index device. Patients will be treated with a knee endoprosthesis with either MXE or a standard gliding surface. Patients will be blinded regarding their treatment. After implantation of the devices, patients will be followed up for 10 years. Besides clinical and patient-related outcomes, radiological data will be collected. In case of revision, the gliding surface will be analyzed biomechanically and regarding the oxidative profile. DISCUSSION: The comparison between MXE and the standard gliding surface in this study will provide clinical data to confirm preceding biomechanical results in vivo. It is assumed that material-related differences will be identified, i.e., that the new material will be less sensitive to wear and creep. This may become obvious in biomechanical analyses of retrieved implants from revised patients and in radiologic analyses. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04618016. Registered 27 October 2020, https://clinicaltrials.gov/study/NCT04618016?term=vikep&checkSpell=false&rank=1 . All items from the World Health Organization Trial Registration Data Set can be found in Additional file 1.

Perioperative Iron Deficiency in Patients Scheduled for Major Elective Surgeries: A French Prospective Multicenter Cross-Sectional Study.

BACKGROUND: The management of perioperative iron deficiency is a component of the concept of patient blood management. The objective of this study was to update French data on the prevalence of iron deficiency in patients scheduled for major surgery. METHODS: The CARENFER PBM study was a prospective cross-sectional study in 46 centers specialized in orthopedic, cardiac, urologic/abdominal, or gynecological surgery. The primary end point was the prevalence of iron deficiency at the time of surgery (D-1/D0) defined as serum ferritin <100 µg/L and/or transferrin saturation (TSAT) <20%. RESULTS: A total of 1494 patients (mean age, 65.7 years; women, 49.3%) were included from July 20, 2021 to January 3, 2022. The prevalence of iron deficiency in the 1494 patients at D-1/D0 was 47.0% (95% confidence interval [CI], 44.5-49.5). At 30 days after surgery, the prevalence of iron deficiency was 45.0% (95% CI, 42.0-48.0) in the 1085 patients with available data. The percentage of patients with anemia and/or iron deficiency increased from 53.6% at D-1/D0 to 71.3% at D30 ( P < .0001), mainly due to the increase of patients with both anemia and iron deficiency (from 12.2% at D-1/D0 to 32.4% at D30; P < .0001). However, a treatment of anemia and/or iron deficiency was administered preoperatively to only 7.7% of patients and postoperatively to 21.7% (intravenous iron, 14.2%). CONCLUSIONS: Iron deficiency was present in half of patients scheduled for major surgery. However, few treatments to correct iron deficiency were implemented preoperatively or postoperatively. There is an urgent need for action to improve these outcomes, including better patient blood management.

Survival and radioclinical evaluation of the Optimys™ short stem at more than 6years' mean follow-up: A retrospective study of 108 cases.

INTRODUCTION: The short stems developed in recent years offer an interesting alternative to standard long stems. The Optimys™ short stem has been widely studied, but not according to the National Institute for Health and Care Excellence (NICE) criteria. We therefore conducted a retrospective study of Optimys™ at a minimum 5years' follow-up, to assess: (1) survival on NICE criteria, (2) complications, (3) functional results, and (4) subsidence, restoration of offset and bone remodeling. HYPOTHESIS: Optimys™ shows survival comparable to that of other non-cemented standard and short stems, with a<0.5% per year revision rate or<2.5% at 5years on NICE criteria. MATERIAL AND METHODS: A single-center retrospective study included 108 Optimys™ stems at a mean 76.5months' follow-up (range: 60-112months). Clinical [Harris, Oxford-12 and forgotten hip (French version: SHO-12) scores] and radiologic data were collected pre- and postoperatively. Analysis focused on implant survival, complications, functional results and radiological results (restoration of offset, bone remodeling, subsidence and osseointegration) and risk factors for stem migration. RESULTS: At a mean 76.5months' follow-up (range: 60-112months), Optimys™ survival was 97.7% (95% CI: 0.945-1). Oxford and Harris scores improved significantly: respectively, 16.1 vs. 44.7 [Δ=28.598; 95% CI: 27.410-29.785 (p<0.001)] and 45.3 vs. 95 [Δ=49.662; 95% CI: 47.442-51.882 (p<0.001)]. Mean forgotten hip score (SHO-12) at last follow-up was 82.7±19.6 (range: 35.4-100.0). There was 1 case of aseptic revision at 11months for femoral osseointegration defect. Mean subsidence was 1.64mm (range: 0-20.63mm); no predisposing factors could be identified. Femoral offset increased by a mean 2.41±4.53mm (range: -10.10 to 14.70mm). CONCLUSION: The present study reports good survival for the Optimys™ stem, which meets NICE criteria. Radiologic and clinical results were encouraging, with a low rate of subsidence, comparable to other series, but with increased femoral offset. LEVEL OF EVIDENCE: IV; retrospective cohort study.

A predictive score of high tibial osteotomy survivorship to help in surgical decision-making: the SKOOP score.

INTRODUCTION: The high tibial osteotomy (HTO) survival rate is strongly correlated with surgical indications and predictive factors. This study aims to assess HTO survival in the long term, to determine the main predictive factors of this survival, to propose a predictive score for HTO based on those factors. METHODS: This multicentric study included 481 HTO between 2004 and 2015. The inclusion criteria were all primary HTO in patients 70 years old and younger, without previous anterior cruciate ligament injury, and without the limitation of body mass index (BMI). The assessed data were preoperative clinical and radiological parameters, the surgical technique, the complications, the HKA (hip knee ankle angle) correction postoperatively, and the surgical revision at the last follow-up. RESULTS: The mean follow-up was 7.8 ± 2.9 years. The HTO survival was 93.1% at 5 years and 74.1% at 10 years. Age < 55, female sex, BMI < 25 kg/m2 and incomplete narrowing were preoperative factors that positively impacted HTO survival. A postoperative HKA angle greater than 180° was a positive factor for HTO survival. The SKOOP (Sfa Knee OsteOtomy Predictive) score, including age (threshold value of 55 years), BMI (threshold values of 25 and 35 kg/m2), and the presence or absence of complete joint line narrowing, have been described. If the scale was greater than 3, the survival probability was significantly lower (p < 0.001) than if the scale was less than 3. CONCLUSION: A predictive score including age, BMI, and the presence or absence of joint line narrowing can be a helpful in making decisions about HTO, particularly in borderline cases. LEVEL OF EVIDENCE: Retrospective cohort study.

Beneficial effect of a zirconium-nitride-coated implant in total knee arthroplasty revision for suspected metal hypersensitivity.

INTRODUCTION: Revision of total knee arthroplasty (rTKA) for suspicion of metal hypersensitivity (MHS) may require hypoallergenic implants. Results for coated implants have not been reported. The aim of the present study was to assess short-term results and survival of rTKA for MHS using a multilayer implant coating. HYPOTHESIS: Multilayer implant coating improves functional results in rTKA, with survival comparable to primary coated implants. MATERIAL AND METHODS: A single-center retrospective observational study included 28 patients (30 knees) undergoing rTKA for MHS using a coated implant between May 2011 and November 2016. Exclusion criteria comprised implant malpositioning and history of infection in the affected knee. Clinical and radiological results were assessed on the International Knee Society (IKS) and SF-36 functional scores and Ewald radiological score. Survival was calculated on Kaplan-Meier estimation. RESULTS: Mean follow-up was 3.8 years. Mean IKS score increased by 40.2 points (40%) [range, 28.1-52.3] (p<0.05). Mean range of motion increased by 17° [range, 9.5-24.5°] (p<0.05). Mean physical and mental SF-36 components were respectively 44.7 and 46.1. Survivorship was 93%. DISCUSSION: There was significant functional improvement after rTKA for MHS. There were no short-term complications related to the zirconium nitrate coating. However, studies with longer follow-up will be needed for confirmation. LEVEL OF EVIDENCE: IV; retrospective study.

Clinical and radiological results after revision THA with distal locking stem: A cohort study of 44 patients.

BACKGROUND: Distal locking stems were developed in response to some complex revision procedures in total hip arthroplasty (THA), providing better axial and rotational stability. The aim of the present study was to assess medium-term clinical and radiological results of treatment with last-generation distal locking stem. HYPOTHESIS: Our hypothesis was that this implant provided a high survival rate. MATERIAL AND METHODS: A single-center retrospective observational study included all patients who underwent THA revision with distal locking stem between April 2013 and January 2015 in our university hospital. The implant was a curved distal-locking stem fully coated in grit-blasted titanium alloy and hydroxyapatite (HA) with a collar made of TiAlV. This concept is based on primary distal fixation by interlocking screws. The primary endpoint was surgical revision for implant exchange. RESULTS: A total of 47 procedures with distal locking stem were performed, 44 of which were included. Minimum follow-up was 5 years. Etiologies of revision comprised 25 femoral loosenings, 13 periprosthetic fractures, 3 infections, and 3 modular taper breakages. Six patients underwent re-revision (13%), with only 1 implant change (98% survival rate). Mean Harris and Oxford Hip scores at last follow-up were respectively 81±13.5 [range, 67.4-94.5] and 26±9⋅2 [range, 16.7-35.2]. Radiologically, no stem subsidence occurred, and bone ingrowth was obtained in all cases. DISCUSSION: Fully-coated distal locking stems showed a high survival rate. They provided strong initial fixation, allowing early full weight-bearing in these frail patients. LEVEL OF EVIDENCE: IV; retrospective series.

French Hip & Knee Society classification of short-stem hip prostheses: Inter- and intra-observer reproducibility.

INTRODUCTION: In total hip replacement (THR), a short stem theoretically provides more physiological force transfer to the proximal femur, conserves bone stock and facilitates minimally invasive surgery. On the other hand, such implants involve a learning curve and incur risk of malpositioning or fracture and of secondary mobilization. There are several types of short stem, and classification is needed. Classifications exist, but are based more on implant length than on anchorage zone, and most have not been tested for reproducibility. The French Hip & Knee Society (SFHG) developed a short-stem classification based on anchorage zone inside the femur. The objectives of the present study were: (1) to present the classification, (2) to apply it to the short-stem models available in France and those widely used worldwide, and (3) to assess reproducibility. HYPOTHESIS: The SFHG short-stem classification enables reproducible comparison. MATERIAL AND METHOD: A short-stem classification according to anchorage zone was drawn up by an expert group. The stems and the classification were presented to 12 surgeons performing THR, who classified the stems according to the classification; a retest was performed 2 months later. RESULTS: The classification is based on femoral stem anchorage site, in 5 types: type 1, cephalic; type 2, isolated cervical; type 3, Calcar femorale; type 4, metaphyseal; and type 5, conventional metaphyseal-diaphyseal, with shortened stems. Inter-observer reproducibility was 92.7% [95%CI: 91.7%-93.6%], with kappa 0.785 [95%CI: 0.755-0.814], and Lin test-rest concordance correlation coefficient 0.852 [95%CI: 0.836-0.869]. Intra-observer reproducibility was 94.0% [95%CI: 91.9%-96.1%], with kappa 0.820 [95%CI: 0.759-0.882], and Lin test-retest concordance correlation coefficient 0.820 [95%CI: 0.792-0.849]. DISCUSSION: This new classification enables femoral implants to be reproducibly compared according to anchorage zone. LEVEL OF EVIDENCE: IV; retrospective study without control group.

Comparison of periprosthetic bone mineral density between two types of short-stems in total hip arthroplasty with a mean follow-up of 4 years.

INTRODUCTION: The use of short stems in primary hip arthroplasty has grown considerably in recent years, with a large variety of designs and stabilization methods available. Few studies have directly compared how these designs and fixation modes influence the bone mineral density (BMD) that is said to be better preserved with shorter implants. This led us to carry out a medium-term retrospective comparative study to (1) specify how the design of two different types of short stems influences the periprosthetic BMD, (2) compare the radiological and clinical outcomes of these stems. HYPOTHESIS: The periprosthetic BMD of a short stem varies based on the implant's design. MATERIALS AND METHODS: Ninety-three patients underwent total hip arthroplasty (THA) with a short stem between July 2012 and July 2014. Two groups of patients were formed: Vitae™ short stem (Adler Ortho, Milan, France), Optimys™ short stem (Mathys, Bettlach, Switzerland). The Vitae group consisted of 46 patients, while the Optimys group consisted of 47 patients. The mean age was 66 years, and the mean body mass index (BMI) was 26 kg/m2. The groups had comparable age, BMI, sex, Harris Hip score and preoperative radiological features. Periprosthetic BMD of the two types of implants was determined between the 1st and 4th year postoperative using dual-energy x-ray absorptiometry (DEXA) in the Gruen zones. The radiological and clinical outcomes were also determined. RESULTS: There was a significant decrease in BMD in zone 7(-5.8%±0.1 CI95%[-0.09; -0.02] (p=0.003)), zone 2 (-4.8% ±0.1 CI95%[-0.093; -0.003] (p=0.038)) and zone 6 (-11% ±0.2 CI95%[-0.19; -0.03] (p=0.009)) in the patients with Vitae stems and in zone 2 (-13.7%±0.3 CI95%[-0.25; -0.03] (p=0.018)) in the patients with Optimys stems. A significant difference in BMD in zone 7 at 1 year (p=0.014) and 4 years (p=0.001) postoperative and in zone 6 (p=0.011) at 4 years postoperative existed between groups, with the Optimys group having higher BMD. There was a significant increase in femoral offset in the Optimys group but not the Vitae group: Δoffset=-0.50 mm±5.2 CI95%[-2.05; 1.05] (p=0.522) and Δoffset=2.79 mm±4.2 CI95%[1.21; 4.37] (p=0.001). The Harris Hip score was not significantly different between the two groups at 4 years postoperative (95.3±2.5 [88; 99] vs. 95.2±2.6 [88; 99] (p=0.991)). DISCUSSION: The design of short stems appears to influence the distribution of loads and the periprosthetic BMD. These stems are associated with very good radiological and clinical results in the medium term. Bone remodeling appears to continue beyond 1 year after the THA procedure. LEVEL OF EVIDENCE: III; Retrospective case-control study.

Sleep Deprivation Adversely Impacts Resident Performance for Simulated Arthroscopy.

PURPOSE: The purpose of the study was to assess the performance of residents in orthopaedics before and after a 24-hour shift on a shoulder arthroscopy simulator. The primary study endpoint was an overall performance score (OPS) generated by the simulator. METHODS: A prospective, comparative study of 120 simulator trials by 10 resident junior surgeons was performed in our university hospital's simulation center between May and November 2018. To avoid memorization bias, all participants performed the same exercise 10 times on a VirtaMed ArthroS simulator prior to the study. Each resident's performance (the OPS, the operating time, the proportion of procedures with iatrogenic lesions, the camera path length and the hook path length) in two different simulated arthroscopy exercise tasks was assessed once before and once after a 24-hour shift. This sequence was performed three times during the semester, and the change over time in performance was also evaluated. RESULTS: The OPS was significantly lower after the night shift (P = 0.035 for the first exercise, and P = 0.025 for the second). CONCLUSION: In a group of previously trained resident junior surgeons, overall performance with an arthroscopy simulator was significantly worse after a 24-hour shift. The study of secondary parameters of the OPS and the subgroup analysis based on the sleep time and Epworth score vary depending on the type of exercise performed arthroscopically. However, the use of a simulator after a night shift did not prevent the trainee from improving his/her level of performance over time. LEVEL OF EVIDENCE: II, a prospective, comparative study.