Use of thioglycolate broth as a pre-analytic transport medium in the diagnosis of prosthetic joint infection.

OBJECTIVES: This study aimed to investigate whether adding tissue samples directly into thioglycolate (TG) broth yielded a greater number of anaerobic organisms than freshly sampled tissue in suspected hip and knee prosthetic joint infections (PJIs). PATIENTS AND METHODS: Between January 2017 and December 2020, a total of 90 patients (46 males, 44 females; median age: 71.7 years; range, 50.8 and 87.8 years) who underwent revision hip or knee arthroplasty were included. Intraoperative samples were taken, with five placed in TG broth and five in standard containers (PC) with subsequent aerobic and anaerobic culturing conducted. Demographic and baseline data of the patients were recorded. The primary outcome was positive bacterial growth from a PJI specimen inoculated directly into TG broth at the time of collection or standard PJI specimen processing. Secondary outcomes investigated were the presence of Cutibacterium acnes (C. acnes) and the curative success of revision procedure. RESULTS: A total of 900 samples (450 PC and 450 TG) were taken from 90 revision arthroplasty patients (47 knees and 43 hips). There was no statistically significant difference in the number of positive bacterial growth samples between TG broth and standard processing (p=0.742). This was consistent with subgroup analysis analyzing C. acnes (p=0.666). CONCLUSION: In hip and knee arthroplasty, there is no benefit in substituting or adding TG broth as a culture medium to better identify both general bacterial species and C. acnes infections specifically. However, the use of TG may be useful in confirming a true positive result for infection.

Observation of a single protein by ultrafast X-ray diffraction.

The idea of using ultrashort X-ray pulses to obtain images of single proteins frozen in time has fascinated and inspired many. It was one of the arguments for building X-ray free-electron lasers. According to theory, the extremely intense pulses provide sufficient signal to dispense with using crystals as an amplifier, and the ultrashort pulse duration permits capturing the diffraction data before the sample inevitably explodes. This was first demonstrated on biological samples a decade ago on the giant mimivirus. Since then, a large collaboration has been pushing the limit of the smallest sample that can be imaged. The ability to capture snapshots on the timescale of atomic vibrations, while keeping the sample at room temperature, may allow probing the entire conformational phase space of macromolecules. Here we show the first observation of an X-ray diffraction pattern from a single protein, that of Escherichia coli GroEL which at 14 nm in diameter is the smallest biological sample ever imaged by X-rays, and demonstrate that the concept of diffraction before destruction extends to single proteins. From the pattern, it is possible to determine the approximate orientation of the protein. Our experiment demonstrates the feasibility of ultrafast imaging of single proteins, opening the way to single-molecule time-resolved studies on the femtosecond timescale.

Does Far Cortical Locking Improve Fracture Healing in Distal Femur Fractures: A Randomised, Controlled, Prospective Multicentre Study.

(1) Background: Bone healing is influenced by various mechanical factors, such as stability, interfragmentary motion, strain rate, and direction of loading. Far cortical locking (FCL) is a novel screw design that promotes bone healing through controlled fracture motion. (2) Methods: This study compared the outcome of distal femur fractures treated with FCL or SL (standard locking) screws and an NCB plate in a randomised controlled prospective multicentre trial. The radiographic union scale (RUST) and healing time was used to quantify bone healing on follow-up imaging. (3) Results: The study included 21 patients with distal femur fractures, 7 treated with SL and 14 treated with FCL screws. The mean working length for patients with SL screws was 6.1, whereas for FCL screws, it was 3.9. The mean RUST score at 6 months post fracture was 8.0 for patients with SL plates and 7.3 for patients with FCL plates (p value > 0.05). The mean healing time was 6.5 months for patients with SL plates and 9.9 months for patients with FCL plates (p value < 0.05). (4) Conclusions: Fractures fixed with SL plates had longer working lengths and faster healing times when compared to FCL constructs, suggesting that an adequate working length is important for fracture healing regardless of screw choice.

Generation of Large Vortex-Free Superfluid Helium Nanodroplets.

Superfluid helium nanodroplets are an ideal environment for the formation of metastable, self-organized dopant nanostructures. However, the presence of vortices often hinders their formation. Here, we demonstrate the generation of vortex-free helium nanodroplets and explore the size range in which they can be produced. From x-ray diffraction images of xenon-doped droplets, we identify that single compact structures, assigned to vortex-free aggregation, prevail up to 10^{8} atoms per droplet. This finding builds the basis for exploring the assembly of far-from-equilibrium nanostructures at low temperatures.

Advances in Hip Replacement Surgery.

Total hip arthroplasty (THA) is one of the most successful types of surgical operation, with some considering it "the operation of the century" [...].

Augmentative Plating versus Exchange Intramedullary Nailing for the Treatment of Aseptic Non-Unions of the Femoral Shaft-A Biomechanical Study in a SawboneTM Model.

BACKGROUND: Non-unions after intramedullary nailing of femoral shaft fractures are a significant problem. Treatment options such as augmenting with plates or exchange nailing have been proposed. The ideal treatment remains controversial. METHODS: Augmentative plating using a 4.5 mm LCP or a 3.2 mm LCP leaving the nail in situ was tested biomechanically and compared to exchange intramedullary nailing in a SawboneTM model of a femoral shaft non-union. RESULTS: The difference of fracture gap motion in axial testing was small. In rotational testing, the exchange nail allowed for the largest amount of motion. The 4.5 mm augmentative plate was the most stable construct in all loading conditions. CONCLUSIONS: Augmentative plating using a 4.5 mm LCP plate while leaving the nail in situ is biomechanically superior to exchange intramedullary nailing. A small fragment 3.2 mm LCP is undersized and does not reduce fracture motion sufficiently in a femoral shaft non-union.

The effect of trunnionosis on the risk of re-revision following femoral head exchange in hip arthroplasty.

BACKGROUND: Fretting corrosion at modular junctions contributes to arthroplasty failure. Currently, no evidence-based guidelines are available regarding the acceptable level of trunnion corrosion that can occur in vivo. We aimed to examine the relationship between trunnion corrosion and risk of re-revision to assist surgeons with intraoperative decision making. METHOD: Grading by 3 independent examiners of revised and re-revised head components was performed using a modified Goldberg corrosion scale. Samples were separated into low-grade (LG) and high-grade (HG) corrosion. Mechanical testing determined the relationship between corrosion severity and pull-off strength at the head-stem junction. RESULTS: 529 retrieved femoral heads were analysed. A positive association was detected between males and HG corrosion (OR 2.07; 95% CI, 1.45-2.94; p < 0.001). No difference between the survivorship of LG and HG heads was detected (p-value = 0.247). In the re-revised sample, the first implant had a time in situ that was on average 7.97 years longer (95% CI, 5.4-10.6) than that of the subsequent re-revised femoral head. Severe corrosion on the first head was associated with a 37.5 (95% CI, 4.00-1944) fold increase of HG on the subsequent head (p < 0.001). Femoral disassembly force had a positive correlation with stem taper corrosion grade (p = 0.001). CONCLUSIONS: A well-fixed stem with corrosion may remain in situ.

Kneeling tolerance following intramedullary nailing or plate fixation of uncomplicated distal tibia fractures.

INTRODUCTION: Distal tibia fractures often occur in younger, high demand patients, though the literature surrounding management remains contentious. This study sought to quantitatively determine differences in kneeling ability and self-reported knee function in patients managed with either intramedullary nailing (IMN) or open reduction internal fixation (ORIF) with compression plating following distal tibia fracture to assist in the preoperative consent process. HYPOTHESIS: There is no difference in kneeling tolerance following either tibial nailing or plate fixation of distal tibia fractures. MATERIAL AND METHODS: Retrospective sampling of public hospital data with outpatient prospective functional testing were completed. The primary outcome measure was the Kneeling Test (KT). Secondary outcome measures were The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Forgotten Joint Score (FJS) for the knee joint. There were 28 patients recruited (18 IMN and 10 ORIF) with a mean age of 44years. Mean overall follow-up was 13.3months (range 8-25, SD 3.6). All fractures had completely healed without postoperative complication. RESULTS: The IMN affected limb had a significantly worse overall kneeling function than their non-affected limb (mean KT: 70.4 vs. 94.9 respectively, p<0.005) Additionally, the IMN group performed significantly worse when compared to the ORIF group (mean KT 70.4 vs. 92.5 respectively, p<0.005). No significant differences (p>0.05) in kneeling function existed for the ORIF group when comparing affected to non-affected limbs. Secondary outcome analysis showed significantly worse overall WOMAC and FJS in the IMN group compared to the ORIF group (mean WOMAC 19.3 vs. 6.9 respectively, p=0.040; mean FJS 38.3 vs. 75.9 respectively, p=0.005). DISCUSSION: The use of intramedullary nailing for the treatment of distal tibia fracture results in a mean reduction of 20% in kneeling tolerance in comparison to ORIF. The resulting kneeling tolerance is comparable to that of patients post-total knee arthroplasty. The present findings should assist in the consent process for patients with high kneeling demands in sportive, professional or cultural pastimes. LEVEL OF EVIDENCE: IV; retrospective cohort study with quantitative outcome measurement.

Intra-articular versus intravenous administration of tranexamic acid in lower limb total arthroplasty: a systematic review and meta-analysis of randomised clinical trials.

AIM: The ideal route of tranexamic acid (TXA) administration in total hip arthroplasty (THA) or total knee arthroplasty (TKA) remains controversial. This study aims to identify the optima route of TXA administration in THA or TKA. METHODS: PUBMED, EMBASE, MEDLINE and CENTRAL database were systematically searched until 4 August 2021 for randomised studies that compared intravenous (IV) or intra-articular (IA) administration of TXA in THA or TKA. RESULTS: Sixty-seven studies enrolling 8335 patients (IA: 4162; IV: 4173) were eligible for quantitative and qualitative analysis. Comparable results were demonstrated in the incidence of venous thromboembolisation (OR:0.96, p = 0.84), total blood loss (MD: - 9.05, p = 0.36), drain output (MD: - 7.36, p = 0.54), hidden blood loss (MD: - 6.85, p = 0.47), postoperative haemoglobin level (MD: 0.01, p = 0.91), haemoglobin drop (MD: - 0.10, p = 0.22), blood transfusion rate (OR: 0.99, p = 0.87), total adverse events (OR: 1.12, p = 0.28), postoperative range of motion (MD: 1.08, p = 0.36), postoperative VAS pain score (MD: 0.13, p = 0.24) and postoperative D-dimer level (MD: 0.61, p = 0.64). IV route of TXA administration was associated with significantly longer length of hospital stay compared to IA route of administration (MD: - 0.22, p = 0.01). CONCLUSION: In this meta-analysis, both IV and IA route of TXA administration were equally effective in managing blood loss and postoperative outcomes in lower limb joints arthroplasty. LEVEL OF EVIDENCE: Level 1. PROSPERO Registration CRD42021271355.

Fracture reduction has a dominant effect over cerclage wiring in increasing stiffness of intertrochanteric OTA/AO 31-A3.1 (reverse oblique) fractures managed with cephalomedullary osteosynthesis.

OBJECTIVES: To investigate the mechanical properties of cephalomedullary nailing of intertrochanteric OTA/AO 31-A3.1 (reverse oblique) fractures and to test the hypothesis that anatomical reduction and augmentation with cerclage wire produces a more stable construct. METHODS: A standardized fracture model in composite saw bone was created to stimulate an intertrochaneric 31-A3.1 fracture, using a 3D printed cutting guide. Simulated osteosynthesis was performed with 12 femurs divided into anatomically reduced and varus malreduced groups. Each femur was tested with and without cerclage wire augmentation. All femurs were fixed with a 215 mm, 130 degree, 11.5 mm nail. An Instron 8874 biaxial materials testing machine was used to assess the axial stiffness. Cyclic loading consisted of 5000 cycles of sinusoidal combined axial-torsion loading at 3 Hz. Axial load was 100 N to 2000 N and torsion -4.5 Nm to +4.5 Nm. Stiffness was measured before and after cyclic loading. RESULTS: Reduced constructs were stiffer than residual varus constructs. The mean overall fracture stiffness was 508.7 N/mm for reduced constructs and 379.2 N/mm for varus constructs. Removing the cables significantly decreased the fracture stiffness for both constructs (mean difference 60.0 N/mm, 95% CI 7.7-112.3, P = .032). CONCLUSIONS: Anatomical reduction has a dominant effect on facture stiffness. Anatomically reduced fractures are stiffer than varus malreduced fractures. A cerclage wire further improves construct stiffness if anatomical reduction is achieved. Cerclage wiring is less effective if anatomical reduction is not achieved.

The 1-Megapixel pnCCD detector for the Small Quantum Systems Instrument at the European XFEL: system and operation aspects.

The X-ray free-electron lasers that became available during the last decade, like the European XFEL (EuXFEL), place high demands on their instrumentation. Especially at low photon energies below 1 keV, detectors with high sensitivity, and consequently low noise and high quantum efficiency, are required to enable facility users to fully exploit the scientific potential of the photon source. A 1-Megapixel pnCCD detector with a 1024 × 1024 pixel format has been installed and commissioned for imaging applications at the Nano-Sized Quantum System (NQS) station of the Small Quantum System (SQS) instrument at EuXFEL. The instrument is currently operating in the energy range between 0.5 and 3 keV and the NQS station is designed for investigations of the interaction of intense FEL pulses with clusters, nano-particles and small bio-molecules, by combining photo-ion and photo-electron spectroscopy with coherent diffraction imaging techniques. The core of the imaging detector is a pn-type charge coupled device (pnCCD) with a pixel pitch of 75 µm × 75 µm. Depending on the experimental scenario, the pnCCD enables imaging of single photons thanks to its very low electronic noise of 3 e- and high quantum efficiency. Here an overview on the EuXFEL pnCCD detector and the results from the commissioning and first user operation at the SQS experiment in June 2019 are presented. The detailed descriptions of the detector design and capabilities, its implementation at EuXFEL both mechanically and from the controls side as well as important data correction steps aim to provide useful background for users planning and analyzing experiments at EuXFEL and may serve as a benchmark for comparing and planning future endstations at other FELs.

Effectiveness of administering tranexamic acid to high-risk hip and knee arthroplasty patients: a systematic review protocol.

OBJECTIVE: The objective of this review is to assess the safety and effectiveness in administering tranexamic acid in high-risk hip and knee arthroplasty patients. INTRODUCTION: Arthroplasty surgery is associated with a significant amount of perioperative blood loss. Tranexamic acid is an antifibrinolytic used to counteract blood loss. Although various studies have demonstrated the effectiveness of tranexamic acid without significant adverse effects, a majority of these studies have excluded high-risk patients. Due to this selection bias there is a lack of clear evidence of the safety of administering tranexamic acid in high-risk patients. INCLUSION CRITERIA: This review will consider studies that included high-risk patients aged >18 years who had previous myocardial infarction including cardiac stents, deep vein thrombosis and/or pulmonary embolism, transient ischemic attacks and/or stroke and clotting disorders. No exclusions will be made for the dosing route of tranexamic acid. The outcomes measured will be 1) thromboembolic complications of deep vein thrombosis, pulmonary embolism, transient ischemic attacks, stroke, myocardial infarction and death; 2) requirements of blood transfusion and 3) the amount of blood loss. METHODS: A search will be conducted in PubMed, Embase, Scopus and Web of Science databases with the results being reported in a PRISMA flow diagram. Selected studies will be critically appraised by two independent reviewers for methodological quality. Study and outcome quality will be reported using the GRADE approach. Data will be extracted using a standardized data extraction tool. Studies will, where possible, be pooled in statistical meta-analysis. Effect sizes will be expressed as either odds ratios (for dichotomous data) or standardized mean differences (for continuous data) and their 95% confidence intervals will be calculated for analysis.

Kneeling difficulty is common following anterior cruciate ligament reconstruction with hamstring autograft and correlates with outcome measures.

INTRODUCTION: Patients frequently have discomfort or difficulty with kneeling following anterior cruciate ligament reconstruction (ACLR). This study aimed to report the prevalence of, and reasons for, kneeling difficulty after ACLR with a hamstring autograft; and to investigate the association between the degree of kneeling difficulty, presence of concurrent meniscal surgery, and clinical outcomes, including patient-reported outcome measures (PROMs) and functional tests. MATERIALS AND METHODS: A total of 104 patients undergoing ACLR with ipsilateral hamstring autograft were enrolled. Participants completed a kneeling difficulty questionnaire and other PROMs including the International Knee Documentation Committee (IKDC) questionnaire, the Knee Injury and Osteoarthritis Outcome Score (KOOS), the Cincinnati Knee Rating System (CKRS), the Lysholm Knee Scoring Scale (LKS), the Tegner Activity Scale (TAS), the 36-Item Short Form Health Survey (SF-36), and the Knee Outcome Survey (KOS). Patients were also assessed objectively via peak isokinetic knee extensor and flexor strength, range of movement (ROM), and functional hop tests. RESULTS: The prevalence of kneeling difficulty on the operated knee was 77% and 54% at 1 and 2 years after ACLR, respectively. Strong associations were observed between kneeling difficulty and PROMs, ranging from CKRS at 1 year of r = 0.403 (95% CI 0.228-0.553, p < 0.001) to KOS at 2 years of r = 0.724 (95% CI 0.618, 0.804, p < 0.001). No associations were observed with age, body mass index, or knee ROM measures. Weak-to-moderate associations were demonstrated with functional hop tests. The degree of kneeling difficulty did not differ with concurrent meniscal surgery. CONCLUSIONS: Kneeling difficulty occurs in as much as 77% of patients following ACLR with hamstring grafts at 1 year, and 54% at 2 years. This has a moderate-to-very strong association with patient-reported assessment of knee pain, symptoms, sport and recreation, and knee-related quality of life. There appears to be no association with patient age, BMI, time from injury to surgery, knee ROM, or concurrent meniscal surgery. LEVEL OF EVIDENCE: IV.

Improved accuracy of CT based measurements for anterior prominence of acetabular prosthesis using a novel protocol based on anatomical landmarks.

BACKGROUND: Anterior hip pain after total hip replacement (THR) can be caused by iliopsoas impingement (IPI). Validation of CT measured cup version is well published; however quantification of the anterior cup prominence has not been validated. Therefore, we did an in vitro study aiming to: (1) assess the accuracy of the current method of measuring the prominence of the acetabular component using a dry bone model; (2) develop a CT protocol based on bony anatomical landmarks that improves the accuracy of these measurements. HYPOTHESIS: We hypothesise that utilising reproducible anatomical landmarks on the acetabulum will improve the accuracy of measurement of anterior prominence at the psoas valley. METHODS: A dry bone pelvic model was implanted with bilateral acetabular cups. The cup was manipulated into ten different combinations of inclination and version, and anterior prominence directly measured in relation to the acetabular rim. A CT scan was performed for each position. Anterior prominence was then measured by two radiologists, first using standard methods (axial slice at level of centre of femoral head) and then again using a novel protocol (based on the position of the psoas valley in relation to the inferior medial acetabular notch). RESULTS: Mean errors between direct measurement of anterior prominence and radiologist reported measurements using standard protocol were 6.94mm±5.24 (SD) (95%Confidence Interval: 3.25-4.27) and 5.14mm±3.07 (95%CI: 1.9-2.5) with a tendency towards overestimation of prominence. Using an anatomical landmark based protocol; mean error was reduced to 3.0mm±1.9 (95%CI: 1.16-1.53) and 4.3mm±4.3 (95%CI: 2.67-351) on the first attempt, and to 1.7mm±1.9 (95%CI: 1.15-1.52) and 2.1mm±1.4 (95%CI: 0.87-1.15) on the second attempt. Concordance correlation improved from 0.43 (95% CI: 0.19-0.68) and 0.59 (95% CI: 0.44-0.79) using the standard protocol, to 0.88 (95%CI: 0.61-0.91) and 0.9 (95%CI: 0.56-0.92) using the novel protocol. CONCLUSIONS: There is a difference in mean error and reliability between radiologically measured values for anterior prominence and values measured directly with present methods. The use of our novel protocol based on bony acetabular landmarks, significantly improves the accuracy of measurement. This protocol may improve reproducibility and the accuracy of this measurement and aid in the decision between tenotomy or revision of the acetabular component. LEVEL OF EVIDENCE: III, in vitro study comparing diagnostic tools.

Scientific instrument Femtosecond X-ray Experiments (FXE): instrumentation and baseline experimental capabilities.

The European X-ray Free-Electron Laser (EuXFEL) delivers extremely intense (>1012 photons pulse-1 and up to 27000 pulses s-1), ultrashort (<100 fs) and transversely coherent X-ray radiation, at a repetition rate of up to 4.5 MHz. Its unique X-ray beam parameters enable novel and groundbreaking experiments in ultrafast photochemistry and material sciences at the Femtosecond X-ray Experiments (FXE) scientific instrument. This paper provides an overview of the currently implemented experimental baseline instrumentation and its performance during the commissioning phase, and a preview of planned improvements. FXE's versatile instrumentation combines the simultaneous application of forward X-ray scattering and X-ray spectroscopy techniques with femtosecond time resolution. These methods will eventually permit exploitation of wide-angle X-ray scattering studies and X-ray emission spectroscopy, along with X-ray absorption spectroscopy, including resonant inelastic X-ray scattering and X-ray Raman scattering. A suite of ultrafast optical lasers throughout the UV-visible and near-IR ranges (extending up to mid-IR in the near future) with pulse length down to 15 fs, synchronized to the X-ray source, serve to initiate dynamic changes in the sample. Time-delayed hard X-ray pulses in the 5-20 keV range are used to probe the ensuing dynamic processes using the suite of X-ray probe tools. FXE is equipped with a primary monochromator, a primary and secondary single-shot spectrometer, and a timing tool to correct the residual timing jitter between laser and X-ray pulses.

The kneeling test is a valid method of assessing kneeling tolerance.

PURPOSE: No quantitative test exists to reliably assess kneeling tolerance before and after surgery. The aim of this study was to validate a kneeling test, designed to quantify kneeling tolerance. METHOD: A total of 179 participants (324 knees) were enrolled into the study, including 124 asymptomatic knees, 98 with osteoarthritis (OA), 85 following total knee arthroplasty (TKA) and 17 following anterior cruciate ligament reconstruction (ACLR). Patients were asked to kneel on a custom-built platform on a soft, firm and hard surface, at both 90° and 110° of knee flexion. A kneeling score of 0-100 was established for 90° and 110° with 100 being a complete absence of pain or discomfort. A linear mixed model with random intercept was used to estimate differences between conditions (healthy, OA, ACLR and TKA). Pearson's correlation coefficient was used to test the strength of the association between the kneeling test and the forgotten joint score (FJS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score. Test-retest reliability was estimated by the intraclass correlation coefficient (ICC). RESULTS: The kneeling test demonstrated good discriminative validity with differences at 110° between asymptomatic knees and knees with OA (difference = - 42, p < 0.001), following ACLR (- 12, p = 0.013) and TKA (- 26, p < 0.001). Similar differences were observed at 90°. The kneeling test demonstrated construct validity, with a moderately strong correlation observed between the kneeling test and the FJS and the WOMAC at 90° (FJS 0.474 [95%CI: 0.357, 0.577], WOMAC - 0.503 [- 0.389, - 0.602]) and 110° (FJS 0.579 [95% CI: 0.479, 0.665], WOMAC - 0.648 [- 0.560, - 0.722]). The ICC for the kneeling test at 90° and 110° was 0.843 (95% CI: 0.745, 0.905) and 0.926 (95% CI: 0.877, 0.956), respectively. CONCLUSIONS: The kneeling test is a valid technique to quantitatively determine kneeling tolerance. It can aid in the assessment and modification of current surgical techniques to improve patient outcomes. LEVEL OF EVIDENCE: III.

Can Prophylactic Cables Stop Crack Propagation in Revision Arthroplasty: A Biomechanical Study.

BACKGROUND: Intraoperative femur fractures are a common complication of revision hip arthroplasty. This study examined the use of a prophylactic cable in stopping a crack from propagating beyond the cable. METHODS: Seventy sheep femora were prepared. A 5-mm vertical incision was performed. Using a force-controlled materials testing machine, a Wagner shaft was advanced until a crack occurred. Cracks were visualized with green ink. In the first part, the control group without any cable (n = 10) was compared with polyethylene (n = 15) and single CoCr cable (n = 15) groups. The cables were positioned 15 mm distal to the osteotomy. In the second part, three different CoCr configurations were compared, single-wrapped (n = 15), double-wrapped (n = 125), and two separate cables at 10 and 15 mm distal to the osteotomy (n = 15). RESULTS: The polyethylene cable stopped only 3 of 15 cracks (20%), whereas the CoCr cable stopped 11 of 15 cracks (73%) (P = .009). The force needed to initiate the crack between the different groups was not significant. Twelve (80%) of 15 cracks were stopped at the level of the cable with two separate CoCr cables and 15 (100%) of 15 cracks with a double-wrapped cable (P = .11). CONCLUSION: This study demonstrated that an elastic cable is not suitable for preventive cabling. The force required to form a crack is not improved with the use of a prophylactic cable placed 10-15 mm below the osteotomy. While the results on the different configurations were not conclusive, the double-wrapped cable was able to stop all cracks from progressing distally.

Normative Values for the Forgotten Joint Score-12 for the US General Population.

BACKGROUND: The Forgotten Joint Score-12 (FJS-12) is a patient-reported outcome questionnaire of joint awareness in patients with hip and knee pathologies. To improve interpretability of values derived from this measure, we collected normative values for the US general population. METHODS: A sample of 2000 participants, representative of US general population, was sought via an online panel. Quota sampling was used to obtain age-specific and sex-specific groups of 200 participants each. The FJS-12 is a 12-item questionnaire assessing the ability to forget the hip or knee joint during activities of daily living. To match US national census data from 2010, raking was used for determining data weights. RESULTS: Normative data for the FJS-12 could be established based on a data set from 2017 respondents (50.1% men; mean age, 54.0 years; 66.3% white/Caucasian). Median FJS-12 scores in the total sample were 75.0 points for knees and 87.5 points for hips. In the age-specific and sex-specific groups, the lowest median score for knees was 54.2 points (men aged 18-39 years) and the highest median was 97.0 (men aged above 70 years). Similarly, median scores for hips were lowest in men aged 18-39 years (60.9 points) and highest in men aged above 70 years (100 points). CONCLUSION: Normative values have been established for the FJS-12 for hips and knees in US general population. Age-specific and sex-specific differences require relying on normative values from the respective groups when interpreting FJS-12 data.

Vitamin C demand is increased after total knee arthroplasty: a double-blind placebo-controlled-randomized study.

PURPOSE: This study was designed to determine whether perioperative supplementation of vitamin C (VC) improves range of motion (ROM) and reduces the risk of arthrofibrosis (AF) following total knee arthroplasty (TKA). METHODS: Ninety-five patients undergoing TKA were randomized to either oral VC (1000 mg daily) or placebo for 50 days (48 VC group, 47 placebo group). The effect of VC supplementation was tested on ROM, AF, WOMAC, FJS-12, and VC plasma concentrations (VCc). VCc were analyzed in both patient groups before surgery, 4 and 7 days after surgery. RESULTS: ROM at 1 year was not different between study groups. The prevalence of AF was 5 of 48 (10.4%) in the VC group compared to 11 of 47 (23.4%) in the placebo group (p = 0.09). VCc decreased post-operatively in the placebo group (49-12 µmol/l on day 7, p < 0.001), but not in the VC group (53-57 µmol/l). Patients with a perioperative drop of VCc ≥ 30 µmol/l developed significantly more AF at 1 year compared to patients with a VCc drop of < 30 µmol/l (p = 0.007). CONCLUSIONS: TKA results in VC depletion. Perioperative VC supplementation prevents VCc drop in most patients undergoing TKA and may lower the incidence of AF. The clinical relevance of this study is that VC supplementation seems to be a cheap and safe adjunct to improve functional outcome after TKA. LEVEL OF EVIDENCE: I. TRIAL REGISTRY: The study was registered at the ISRCTN registry with study ID ISRCTN40250576.

Failure and Fatigue Fracture at the Femoral Stem-Metaphyseal Sleeve Junction in a Modular Knee Prosthesis: A Case Report.

CASE: A 66-year-old active man had undergone revision total knee replacement surgery with a femoral metaphyseal sleeve and a cemented stem in 2013 after loosening of the implant following the primary knee arthroplasty. He was overweight and had a high activity level, and there had been progressive osteolysis surrounding the distal aspect of the femoral sleeve. In 2017, the metaphyseal sleeve had loosened, resulting in corrosion of the threaded taper and catastrophic failure of the implant, with a fracture of the stem at the junction of the sleeve. CONCLUSION: This unique method of failure in this knee implant highlights a weak point in the design. Clinicians must be aware of the increased likelihood of this type of failure with these implants in patients who have contributory factors.