Surgical principles for complex primary total knee arthroplasty in the presence of extra-articular deformity.

Background: Accurate restoration of alignment is vital to the success of a total knee arthroplasty (TKA) procedure. Deformities, whether these are intra-articular and/or extra-articular AND/OR whether these are uniplanar/multiplanar/complex, can impose varying technical challenges in surgical planning and execution. Literature on performing TKA in presence of limb deformity is limited, especially for extra-articular deformities. Objectives: The objectives of this narrative review are twofold. Firstly, we analyse the existing English literature for studies focussed on TKA and deformity correction and summarise the important points about deformity pathomechanics, clinical and radiological assessment, pre-operative planning and surgical techniques. The second objective is to provide the readers with a simplistic and wholistic management algorithm to assist surgeons in meticulous planning to tackle the technical challenges imposed by lower limb deformities while performing a TKA. Discussion: Approach to each patient must be holistic and customised on an individual basis according to patient characteristics, deformity characteristics and surgeon experience. The three main options available are: (1) Primary TKA (symmetric cuts/asymmetric cuts with/without computer navigation assistance) (2) Single stage corrective osteotomy and TKA and (3) Two-staged deformity correction and TKA. A multi-disciplinary team approach is required and a knee surgeon well-versed in revision arthroplasty and a limb reconstruction surgeon specialising in deformity correction, should be involved from the outset. The use of computer navigation technology, particularly for deformity correction and TKA, has increased over the last couple of decades and is recommended by the authors for these challenging cases.

The effects of remote work on collaboration among information workers.

The coronavirus disease 2019 (COVID-19) pandemic caused a rapid shift to full-time remote work for many information workers. Viewing this shift as a natural experiment in which some workers were already working remotely before the pandemic enables us to separate the effects of firm-wide remote work from other pandemic-related confounding factors. Here, we use rich data on the emails, calendars, instant messages, video/audio calls and workweek hours of 61,182 US Microsoft employees over the first six months of 2020 to estimate the causal effects of firm-wide remote work on collaboration and communication. Our results show that firm-wide remote work caused the collaboration network of workers to become more static and siloed, with fewer bridges between disparate parts. Furthermore, there was a decrease in synchronous communication and an increase in asynchronous communication. Together, these effects may make it harder for employees to acquire and share new information across the network.

Fibular head transfixion wire and its relationship to common peroneal nerve: cadaveric analysis.

Proximal tibio-fibular joint is routinely stabilised during leg lengthening, peri-articular fractures and deformity corrections of tibia. Potential injury to the common peroneal nerve at the level of the fibula head/neck junction during wire insertion is a recognised complication. Previous studies have mapped the course of the common peroneal nerve and its branches at the level of the fibular head, and guidelines are published regarding placement of proximal tibial wires. This study aims to relate the course of the common peroneal nerve to the placement of a lateral insertion fibula head transfixion wire. Standard 1.8-mm Ilizarov 'olive' wires were inserted in the fibula head of 10 un-embalmed cadaveric knees. Wires were inserted percutaneously to the fibula head using surface anatomy landmarks and palpation technique. The course of the common peroneal nerve was then dissected. Distances from wire entry point to the course of the common peroneal nerve were measured post-wire insertion. The mean distance of the common peroneal nerve from the anterior aspect of the broadest point of the fibular head was 24.5 mm (range 14.2-37.7 mm). Common peroneal nerve was seen to cross the neck of fibula at a mean distance of 34.8 mm from the tip of fibula (range 21.5-44.3 mm). Wire placement was found to be on average, 52 % of the maximal AP diameter of the fibula head and 64 % of the distance from tip of fibula to the point of nerve crossing fibula neck. When inserting a fibula head transfixion wire, care must be taken not to place wire entry point too distal or posterior on the fibula head. Observing a safe zone in the anterior half of the proximal 20 mm of the fibula head would avoid injury to the nerve. In cases where palpation of fibula is difficult due to patient habitus, we recommend consideration of the use of fluoroscopic guidance during wire transfixion of the proximal tibio-fibular articulation to avoid wire insertion too distally and subsequent potential nerve injury.

Cadaveric analysis of capsular attachments of the distal femur related to pin and wire placement.

OBJECTIVES: Septic arthritis following intra-capsular penetration of the knee by external fixation devices is a complication of traction/fixation devices inserted in the lower extremity [1,2]. The authors were unable to find reference to or exact measurements of the capsular attachments relating to the distal femur documented in the current literature. This study aimed to demonstrate the capsular attachments and reflections of the distal femur to determine safe placements of wires or traction devices. METHODS: The attachments of the capsule to the distal femur were measured in 10 unembalmed cadaveric knees. Capsular attachments were measured anteriorly at the maximal extension of the supra-patella pouch. Medially and laterally measurements were expressed as percentages related to the maximal AP diameter of the distal femur. RESULTS: Mean distance from the centre of the anterior part of the notch to the superior fold was 79.5mm (Range 48.1-120.7 mm). The medial capsular reflections measured in a plane from the adductor tubercle to the anterior edge of the medial femoral condyle demonstrated the capsular reflection was attached an average of 57% back from the anterior edge (Range 41-74%). Laterally the capsular reflections on a line drawn from the maximal diameter in the sagittal plane were attached an average of 48% from the anterior reference point (Range 33-57%). Measuring the reflections at 45 degrees to the long axis of the femur in the sagittal plane the attachment was an average of 51% from the anterior reference point. CONCLUSIONS: Capsular reflections varied among specimens. Medially the capsule attachment was up to 74% of diameter of distal femur at the level of the adductor tubercle. Therefore, the insertion of distal femoral traction pins or similar should be placed proximal to the adductor tubercle and no further than 25% of the distance to the anterior cortex. Care is also needed to ensure pins do not travel to exit too anteriorly on the lateral side as capsular attachments were found to be up to a distance 48% of the diameter of the femur from anterior reference point. Distal condylar extra-articular fixation with Schanz screws is feasible if orientated in the oblique plane.

The MRCS examination--an update on the latest facts and figures.

The Intercollegiate Committee for Basic Surgical Examinations (ICBSE) is responsible for the standard, quality assurance, and continued development of both the MRCS and the Diploma in Otolaryngology and Head and Neck Surgery (DOHNS). It is accountable to the 4 Royal Colleges of Surgeons in the U.K. and Ireland, and the General Medical Council (GMC). This article gives information and an update (including pass rates) for candidates and trainers on the 2013 MRCS format, and summarises the most recent changes to the examination made by the ICBSE with the approval of the GMC.

Penicillin susceptibility and macrolide-lincosamide-streptogramin B resistance in group B Streptococcus isolates from a Canadian hospital.

BACKGROUND: Intrapartum antibiotic prophylaxis (IAP) is recommended for pregnant women who test positive for group B Streptococcus (GBS) in their genitourinary tract to prevent GBS-induced neonatal sepsis. Penicillin G is used as the primary antibiotic, and clindamycin or erythromycin as the secondary, if allergies exist. Decreased susceptibility to penicillin G has occasionally been reported; however, clindamycin and erythromycin resistance is on the rise and is causing concern over the use of clindamycin and erythromycin IAP. METHODS: Antibiotic resistance was characterized phenotypically using a D-Test for erythromycin and clindamycin, while an E-Test (E-strip) was used for penicillin G. GBS was isolated from vaginal-rectal swabs and serologically confirmed using Prolex (Pro-Lab Diagnostics, Canada) streptococcal grouping reagents. Susceptibility testing of isolates was performed according to the Clinical Laboratory Standards Institute guidelines. RESULTS: All 158 isolates were penicillin G sensitive. Inducible macrolide-lincosamide-streptogramin B (MLSB) resistance was observed in 13.9% of isolates. Constitutive MLSB resistance was observed in 12.7% of isolates. M phenotype resistance was observed in 6.3% of isolates. In total, erythromycin resistance was present in 32.9% of the GBS isolates, while clindamycin resistance was present in 26.6%. DISCUSSION: The sampled GBS population showed no sign of reduced penicillin susceptibility, with all being well under susceptible minimum inhibitory concentration values. These data are congruent with the large body of evidence showing that penicillin G remains the most reliable clinical antibiotic for IAP. Clindamycin and erythromycin resistance was higher than expected, contributing to a growing body of evidence that suggests the re-evaluation of clindamycin and erythromycin IAP is warranted.

HISTORIQUE: La prophylaxie antibiotique intrapartum (PAI) est recommandée chez les femmes enceintes positives au Streptococcus du groupe B (SGB) dans l'appareil génito-urinaire, afin de prévenir la septicémie néonatale induite par le SGB. La pénicilline G est utilisée comme antibiotique primaire et, en cas d'allergies, la clindamycine ou l'érythromycine comme antibiotique secondaire. On déclare parfois une diminution de la susceptibilité à la pénicilline G, mais la résistance à la clindamycine et à l'érythromycine est à la hausse et suscite des inquiétudes quant à leur utilisation en PAI. MÉTHODOLOGIE: Les chercheurs ont caractérisé les phénotypes de résistance aux antibiotiques au moyen d'un test de diffusion pour l'érythromycine et la clindamycine et d'un test E (bandelette E) pour la pénicilline G. Ils ont isolé le SGB dans les écouvillons vagino-rectaux et en ont fait la confirmation sérologique au moyen des réactifs de groupement streptococcique Prolex (Pro-Lab Diagnostics, Canada). Les tests de susceptibilité des isolats ont été exécutés conformément aux lignes directrices du Clinical Laboratory Standards Institute. RÉSULTATS: Les 158 isolats étaient sensibles à la pénicilline G. Les chercheurs ont observé une résistance au macrolide, à la lincosamide et à la streptogramine de type B (MLSB) dans 13,9 % des isolats. Ils ont observé une résistance à MLSB dans 12,7 % des isolats et la résistance au phénotype M dans 6,3 % des isolats. Au total, ils ont constaté une résistance à l'érythromycine dans 32,9 % des isolats de SGB, et une résistance à la clindamycine dans 26,6 % des cas. EXPOSÉ: L'échantillon de population atteint du SGB n'a révélé aucun signe de diminution de la susceptibilité à la pénicilline, car tous les sujets se situaient bien en deçà des valeurs CMI susceptibles. Ces données coïncident avec le vaste ensemble de données probantes démontrant que la pénicilline G demeure l'antibiotique clinique le plus fiable pour la PIA. La résistance à la clindamycine et à l'érythromycine était plus élevée que prévu, ce qui contribue à l'ensemble croissant de données probantes indiquant qu'il faut réévaluer la PIA à la clindamycine et à l'érythromycine.

Virtual arthroscopy trainer for minimally invasive surgery.

The presented work introduces an innovative technology solution to a major challenge in minimally invasive surgical training. It is focused on the development of a low-cost, real-time simulation of arthroscopy accessible online via the web. The aim is to enable users to develop their cognitive skills and to comprehend the disorientating images seen through arthroscopes. The simulation is incorporated into a software training tool that provides virtual arthroscopy and e-learning and assessment.

Haptic feedback can provide an objective assessment of arthroscopic skills.

UNLABELLED: The outcome of arthroscopic procedures is related to the surgeon's skills in arthroscopy. Currently, evaluation of such skills relies on direct observation by a surgeon trainer. This type of assessment, by its nature, is subjective and time-consuming. The aim of our study was to identify whether haptic information generated from arthroscopic tools could distinguish between skilled and less skilled surgeons. A standard arthroscopic probe was fitted with a force/torque sensor. The probe was used by five surgeons with different levels of experience in knee arthroscopy performing 11 different tasks in 10 standard knee arthroscopies. The force/torque data from the hand and tool interface were recorded and synchronized with a video recording of the procedure. The torque magnitude and patterns generated were analyzed and compared. A computerized system was used to analyze the force/torque signature based on general principles for quality of performance using such measures as economy in movement, time efficiency, and consistency in performance. The results showed a considerable correlation between three haptic parameters and the surgeon's experience, which could be used in an automated objective assessment system for arthroscopic surgery. LEVEL OF EVIDENCE: Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Fungal osteomyelitis of the axial border of the proximal sesamoid bones in a horse.

CASE DESCRIPTION: A 12-year-old Standardbred gelding was referred for swelling of the right metacarpophalangeal joint. CLINICAL FINDINGS: Ultrasonography of the right metacarpal area revealed hypoechoic areas in the right digital sheath and metacarpophalangeal joint consistent with synovial effusion. Radiography of the right metacarpophalangeal joint revealed lysis of the axial border of the proximal sesamoid bones. Aspergillus fumigatus was detected on fungal culture of synovial fluid. TREATMENT AND OUTCOME: Regional limb perfusion (150 mg of amikacin in 60 mL of saline [0.9% NaCl] solution perfused for 30 minutes) was performed 2 and 4 days after admission. Itraconazole (5 mg/kg [2.27 mg/lb], PO, q 24 h) was administered for approximately 9 weeks. Joint lavage with amikacin (500 mg) in 1 L of saline solution was performed 4 times. Three months after discharge, the owner reported that the horse was mildly lame during trotting but was moving freely and comfortably during all gaits and had gained a considerable amount of weight. Because the osteoarthritis was not expected to improve and because it was recommended that the horse not return to purposeful exercise, the owner decided to retire the horse from racing. CLINICAL RELEVANCE: Various diagnostic imaging methods and fungal cultures are useful for diagnosing fungal osteomyelitis of the axial borders of the proximal sesamoid bones in horses. Fungal osteomyelitis of the sesamoid bones and erosive arthritis should be considered as a differential diagnosis for horses in which corticosteroids have been administered intra-articularly.

Timing of antibiotic prophylaxis in surgery for adult hip fracture.

BACKGROUND: Antibiotic prophylaxis is widely used in surgery for hip fractures. METHODS AND RESULTS: In a retrospective study of case notes of 100 patients, frequent inaccuracies in dose administration were observed. This was applicable to both the pre-operative and the postoperative doses. Longer time intervals between the doses, failure to administer the prescribed doses, and failure of proper documentation were observed. CONCLUSIONS: Improvement in the awareness of staff and timely administration of prophylactic antibiotic has resulted from this study.

Quantification of T(2) relaxation changes in articular cartilage with in situ mechanical loading of the knee.

PURPOSE: To devise a method for producing in vivo MRI images of the knee under physiologically significant loading, and to compare and evaluate the changes in cartilage characteristics before and during in situ compression of the knee. MATERIAL AND METHODS: A total of 26 asymptomatic subjects were imaged on a 1.5 Tesla Philips Intera scanner using a commercially available knee coil. Routine anatomical images were followed by T(2) map acquisition. These scans were repeated following in situ compression of the knee using a MR compatible loading jig. RESULTS: Following loading to body weight, several regions of femoral cartilage show early alteration of T(2) relaxation time, most significantly in the medial and lateral peripheral zones. There were no significant changes in the tibial cartilage. CONCLUSIONS: The results establish the feasibility of measuring changes on MRI with in situ axial loading.