Chronic osteomyelitis caused by Achromobacter xylosoxidans following orthopaedic trauma: A case report and review of the literature.

BACKGROUND: Achromobacter xylosoxidans is an opportunistic environmental aerobe. In cases where A. xylosoxidans infects humans, it most commonly manifests as bacteraemia in the immunosuppressed. A. xylosoxidans causing chronic osteomyelitis is rare, particularly in the immunocompetent and young. CASE: We present the case of a 23-year-old man with chronic osteomyelitis of the right femur caused by co-infection of A. xylosoxidans and Staphylococcus aureus. Five years earlier, he had sustained a right femur fracture and was treated with intramedullary fixation at a peripheral hospital in a developing nation. Past medical history was otherwise unremarkable. Management comprised of surgical debridement and culture-directed antibiotic therapy, resulting in clinical cure. CONCLUSION: In the context of local trauma and previous surgery, osteomyelitis caused by atypical pathogens must be considered. A multidisciplinary approach commensurate with duration and severity of infection and tailored to the causative organism is paramount.

Stable Lateral Meniscal Posterior Root Tears Left In Situ at Time of Anterior Cruciate Ligament Reconstruction Are of Minimal Long-Term Clinical Detriment.

PURPOSE: The purpose of this study was to compare long-term patient-reported outcomes in patients undergoing anterior cruciate ligament (ACL) reconstruction with untreated stable lateral meniscal posterior root (LMPR) tears to those with an intact meniscus. METHODS: Four hundred ninety-two subjects were followed for a minimum of 15-years post-ACL reconstruction and evaluated by an International Knee Documentation Committee questionnaire. The integrity of the meniscus was classified at surgery. Patients were grouped as either untreated injury to LMPR "with stable tear" (WST) group (n = 52) or intact lateral meniscus "no tear" (NT) group (n = 440). WST group included tears where those with a root avulsion within 9 mm of insertion and parrot beak tears with the integrity of the root attachment maintained. Outcomes were compared between groups. RESULTS: ACL graft rupture occurred in 10% in the WST group and in 11% in the NT group (P = .78). For participants with an intact graft (n = 440), the mean International Knee Documentation Committee scores were 82, in the WST group, and 87, in the NT group (P = .03), with a small effect size of .32. The WST group had a worse mean pain severity score (P = .04) and higher frequency of pain (P = .03) than the NT group, but the effect size was small (P < 0.3). There was no difference in the overall knee function (P = .209) or International Knee Documentation Committee activity level (P = .882). CONCLUSION: There was no adverse clinical outcome to leaving a stable LMPR tear in situ at the time of ACL reconstruction. LMPR tears left in situ were of minimal clinically significant long-term detriment, with outcomes similar to having an intact meniscus. There is an innate desire to fix the broken, but posterior meniscal root avulsions and stable parrot beak tears within 9 mm of insertion may not require intervention. At 15 years postinjury, most patients with a stable tear left in situ continue to enjoy an active lifestyle with a pain-free knee. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Allograft Donor Characteristics Significantly Influence Graft Rupture After Anterior Cruciate Ligament Reconstruction in a Young Active Population.

BACKGROUND: Graft selection in anterior cruciate ligament (ACL) surgery can be difficult in a young active population given their high rates of reinjury. Allografts allow for control over graft size and reduce morbidity of autograft harvest. There are mixed results about the use of allograft in the literature; however, the influence of the properties of the allograft on outcomes has not been considered. HYPOTHESIS: ACL reconstruction with allografts from older donors will have a higher rate of graft rupture when compared with allograft from young donors. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Patients (N = 211) aged 13 to 25 years underwent primary ACL reconstruction with fresh-frozen nonirradiated allograft. Four graft types were used: patellar tendon, Achilles tendon, tibialis anterior, and tibialis posterior. Details were collected on allograft donor age and sex. At a minimum of 24 months, patients were evaluated for any further injuries and subjective analysis by International Knee Documentation Committee (IKDC) questionnaire. RESULTS: ACL graft rupture occurred in 23.5%. When grafts were separated into single strand (patellar and Achilles tendon) and multistrand (tibialis anterior and posterior), there was a significantly higher rate of reinjury in the single-strand grafts (29.9% vs 11%; P = .014). Grafts from female donors aged ≥50 years had significantly higher rates of ACL graft rupture (52.6%; P = .003) with increased odds by 6.7 times when compared with grafts from male donors aged <50 years. There was no significant difference in mean IKDC scores among the groups based on the age and sex of the allograft donor. CONCLUSION: The age and sex of the allograft donor and the morphology of the graft significantly influenced the rate of ACL graft rupture in young active patients. Tendons from female donors aged ≥50 years should be avoided given the higher rerupture rates as compared with male donors of any age and younger females.

Utility of preoperative blood screening before hip and knee arthroplasty.

BACKGROUND: It is engrained in medical training that routine blood screening prior to arthroplasty is necessary for optimal patient care. There is little evidence to support their utility and the aggregate cost to the health system. The purpose of this study was to evaluate preoperative blood screening by identifying the frequency of an abnormal result and to examine the influence of age, gender and body mass index on the frequency of abnormal blood pathology. METHODS: This is a retrospective review of 1000 patients from a single centre who underwent elective primary hip or knee arthroplasty from 2015 to 2017. Abnormal blood results were identified and clinically relevant intervals were created for routine markers. RESULTS: A total of 939 patients had available pathology results with 84% identified as having an abnormal result and 47% having a clinically important range. Abnormal liver function tests and ferritin were most common. With increasing age, there was a significant increase in rates of abnormal clinically important range, renal dysfunction, abnormal haemoglobin and erythrocyte sedimentation rate. Males and patients with body mass index >40 had an increased rate of abnormal results, particularly liver function tests. CONCLUSION: The ordering of preoperative investigations prior to lower limb arthroplasty is recommended by the National Institute for Health and Care Excellence guidelines, alleviating concern of post-operative complications and covering medicolegal issues. Our study determined a high frequency of abnormal results, justifying routine blood screening is recommended prior to surgery, particularly for the elderly, males and obese patients.

Sagittal Stability and Implant Design Affect Patient Reported Outcomes After Total Knee Arthroplasty.

BACKGROUND: Joint stability is one of the goals of any joint replacement. The contribution of prosthesis design to sagittal stability in total knee arthroplasty (TKA) has emerged as an area of interest. The purpose of this study was to evaluate the sagittal stability of four prosthesis types and determine the effect on patient reported outcome measures (PROMs). METHODS: A matched-cohort cross-sectional study was performed on 60 patients after TKA at 1-year follow-up. Three surgeons performed 10 medially stabilized (MS) TKA and 10 non-MS TKA. Sagittal stability was assessed by a blinded observer using a KT-1000 arthrometer, Lachman's test, and the anterior drawer test. PROMs (Oxford, Knee Injury and Osteoarthritis Outcome Score, Western Ontario and McMaster Universities Osteoarthritis Index, Forgotten joint score) and visual analog scale assessed function and satisfaction. RESULTS: MS TKA had significantly decreased translation on KT-1000 and improved stability compared with non-MS TKA (P < .05). Increased PROMs were demonstrated in the MS TKA group compared with the non-MS TKA group (P < .05). When divided based on objective stability, regardless of the prosthesis type, patients with a stable knee had superior PROMs (P < .05), particularly in sport-related questions. CONCLUSION: The MS TKA had significantly greater sagittal stability, improved PROMs, and satisfaction compared with non-MS TKA. Independent of prosthesis design, patients with greater sagittal stability demonstrated improved PROMs.

A Randomized Controlled Trial of PEEK Versus Titanium Interference Screws for Anterior Cruciate Ligament Reconstruction With 2-Year Follow-up.

BACKGROUND: Graft fixation with interference screws for anterior cruciate ligament (ACL) reconstruction is a highly successful technique. Polyether ether ketone (PEEK) is a novel thermoplastic polymer with high biocompatibility and mechanical properties that mimic native bone, and it can be imaged on computed tomography or magnetic resonance imaging (MRI) without signal flare. PURPOSE: To compare the clinical performance of ACL reconstruction with PEEK and titanium interference screws at 2 years and to evaluate a novel method of measuring tunnel volume. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A total of 133 patients underwent arthroscopic ACL reconstruction with 4-strand hamstring autografts and were randomized to have titanium or PEEK interference screws for femoral and tibial tunnel fixation. At 2 years, subjective Lysholm and International Knee Documentation Committee scores were assessed and clinical examination performed. At 12 months, MRI was performed to assess graft incorporation and cyst formation, and a novel technique was employed to measure tunnel volumes. RESULTS: There were no significant differences in graft rerupture rate, contralateral ACL rupture rate, subjective outcomes, or objective outcomes. In the titanium and PEEK groups, MRI demonstrated high overall rates of graft integration (96%-100% and 90%-93%, respectively) and ligamentization (89% and 84%) and low rates of synovitis (22% and 10%) and cyst formation (0%-18% and 13%-15%). There was a higher proportion of patients with incomplete graft integration within the femoral tunnel in the PEEK group as compared with the titanium group (10% vs 0%, P = .03); however, the authors suggest that metal artifact precluded proper assessment of the graft in the titanium group by MRI. Tunnel volumes also appeared to be equivalent in the 2 groups and were measured with a novel technique that was highly reproducible in the PEEK group secondary to the absence of flare. CONCLUSION: Two-year clinical analysis of PEEK interference screws for femoral and tibial fixation of ACL reconstructions showed equivalent clinical performance to titanium interference screws. Given the excellent mechanical characteristics, biological compatibility, and absence of metal artifact on MRI, PEEK has become our material of choice for interference screw fixation in ACL reconstruction.

Midterm Outcomes of Arthroscopic Reduction and Internal Fixation of Anterior Cruciate Ligament Tibial Eminence Avulsion Fractures With K-Wire Fixation.

PURPOSE: To determine the clinical and radiological outcomes of patients who underwent arthroscopic reduction and internal fixation of a tibial eminence avulsion fracture with Kirshner wires (K-wires) at a mean of 8 years following surgery. METHODS: This was a retrospective study with prospectively collected data. Inclusion criteria consisted of patients who underwent arthroscopic reduction and internal fixation of tibial eminence fracture with K-wires between 1989 and 2015 at a minimum of 18 months follow-up. Assessment included the International Knee Documentation Committee Ligament Evaluation, Lysholm Knee Score, and clinical outcomes. Magnetic resonance imaging (MRI) was performed to evaluate the anterior cruciate ligament (ACL) and evidence of osteoarthritis. RESULTS: A total of 48 participants met the inclusion criteria, and 32 were reviewed at a mean of 8 years (range, 18-260 months) after surgery. The mean age at the time of surgery was 24.5 years (10-55 years). Subsequent ACL injury occurred in 5 participants (10.4%) on the index knee and in 1 participant also on the contralateral knee; 86% had a normal examination, and no patients had >5-mm side-to-side difference on instrumented testing. The mean International Knee Documentation Committee subjective score at 8 years was 86 (range, 40-100). On MRI scan assessment for osteoarthritic changes at final follow-up, 82% of participants had no evidence of chondral wear on the medial compartment and 73% had no changes in the lateral compartment according to Magnetic Resonance Image Osteoarthritis Knee Score classification. On MRI scan qualitative assessment of ACL and tibial eminence, 7 participants (32%) were found to have high signal at the fracture site. The mean medial tibial eminence height was 9.2 mm (range, 6.3 mm to 1.31 cm) and the lateral tibial eminence height was an average of 6.7 mm (range, 0.38-0.97 mm). Significant kneeling pain was reported by 8 participants (25%). CONCLUSIONS: This study indicates that internal fixation with K-wires is an acceptable approach to reduce tibial eminence avulsion fractures, providing excellent clinical and radiological outcomes at a minimum of 18 months of follow-up. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Fine structure of the Arabidopsis stem cuticle: effects of fixation and changes over development.

MAIN CONCLUSION: The Arabidopsis cuticle, as observed by electron microscopy, consists primarily of the cutin/cutan matrix. The cuticle possesses a complex substructure, which is correlated with the presence of intracuticular waxes. The plant cuticle is composed of an insoluble polyester, cutin, and organic solvent soluble cuticular waxes, which are embedded within and coat the surface of the cutin matrix. How these components are arranged in the cuticle is not well understood. The Arabidopsis cuticle is commonly understood as 'amorphous,' lacking in ultrastructural features, and is often observed as a thin (~80-100 nm) electron-dense layer on the surface of the cell wall. To examine this cuticle in more detail, we examined cuticles from both rapidly elongating and mature sections of the stem and compared the preservation of the cuticles using conventional chemical fixation methods and high-pressure freezing/freeze-substitution (HPF/FS). We found that HPF/FS preparation revealed a complex cuticle substructure, which was more evident in older stems. We also found that the cuticle increases in thickness with development, indicating an accretion of polymeric material, likely in the form of the non-hydrolyzable polymer, cutan. When wax was extracted by chloroform immersion prior to sample preparation, the contribution of waxes to cuticle morphology was revealed. Overall, the electron-dense cuticle layer was still visible but there was loss of the cuticle substructure. Furthermore, the cuticle of cer6, a wax-deficient mutant, also lacked this substructure, suggesting that these fine striations were dependent on the presence of cuticular waxes. Our findings show that HPF/FS preparation can better preserve plant cuticles, but also provide new insights into the fine structure of the Arabidopsis cuticle.

Examining the influence of action on spatial working memory: the importance of selection.

We report three experiments that examine the influence of pointing-to relative to passively viewing an array of objects that participants are attempting to memorize. Recently, Chum, Bekkering, Dodd, and Pratt (2007) provided evidence that pointing to objects enhanced memory relative to passively viewing objects when pointing instruction was manipulated within trial (e.g., point to one array but passively view the other). We replicate this result but also demonstrate that when pointing instruction is blocked (e.g., participants point to or passively view all items in an array as opposed to pointing to some while passively viewing others), pointing to an array of objects actually decreases memory relative to passively viewing that array. Moreover, when pointing is manipulated within trial, the influence of action on working-memory performance appears to be attributable to an enhancement of processing of the pointed-to items as well as a subsequent inhibition of the passively viewed array. These results demonstrate that while action can enhance working memory under conditions where a subset of items is actively selected for additional processing, when selection is not a requirement (e.g., either point to everything or passively view everything), action decreases working-memory performance. Thus, the relationship between action and spatial working memory is complex and context dependent. These results are also discussed as they relate to other similar phenomena (e.g., retrieval-induced forgetting, Corsi Blocks test) in which selection during processing may be critical, and collectively these results provide important insight into spatial working memory and the factors that influence it.