Rapid bacterial evaluation beyond the colony forming unit in osteomyelitis.

Examination of bacteria/host cell interactions is important for understanding the aetiology of many infectious diseases. The colony forming unit (CFU) has been the standard for quantifying bacterial burden for the past century, however, this suffers from low sensitivity and is dependent on bacterial culturability in vitro. Our data demonstrate the discrepancy between the CFU and bacterial genome copy number in an osteomyelitis-relevant co-culture system and we confirm diagnosis and quantify bacterial load in clinical bone specimens. This study provides an improved workflow for the quantification of bacterial burden in such cases.

Long Cephalomedullary Nails Can Be a Cheap and Effective Interval Revision Prosthesis in Infected Hip Replacements That Require Proximal Femoral Replacement: A Small Case Series.

Hip prosthetic joint infection management is complex and expensive, especially in severe bone loss. Reducing the price of interval prosthesis when performing staged revision could minimize costs without compromising outcomes. We present 2 similar techniques developed independently that use an antibiotic-coated cephalomedullary nail with a total hip arthroplasty bearing (head and cemented acetabular component) attached to it as an interval proximal femoral replacement prosthesis. Using this technique, the femoral implant cost was reduced up to 10-fold. All patients have recovered well with resolution of infection and functional recovery similar to patients undergoing proximal femoral replacement. In one case, the lag screw (femoral neck) fractured at 5 months prompting the second-stage revision. This complication should be considered when deciding the timing of second-stage revisions in these cases.

Staged Revision Hip Arthroplasty With Femoral Impaction Bone Grafting for Prosthetic Joint Infections: Radiostereometric Analyses and Clinical Outcomes at Minimum 5-Year Follow-Up.

BACKGROUND: There are ongoing concerns regarding the use of bone graft following prosthetic joint infection and subsequent implant subsidence. The aim of this study was to determine whether the use of a cemented stem combined with femoral impaction bone grafting (FIBG) at second stage revision for infection results in stable femoral stem fixation, determined by accurate methods, and good clinical results. METHODS: A prospective cohort of 29 patients underwent staged revision total hip arthroplasty for infection using an interval prosthesis followed by FIBG at the final reconstruction. The mean follow-up was 89 months (range, 8 to 167 months). Femoral implant subsidence was measured with radiostereometric analysis. Clinical outcomes included the Harris Hip Score, Harris Pain score and Société Internationale de Chirurgie Orthopédique et de Traumatologie activity scores. RESULTS: At 2-years follow-up the median stem subsidence relative to femur was -1.36 mm (range, -0.31 to -4.98), while the cement subsidence relative to femur was -0.05 mm (range, 0.36 to -0.73). At 5-years follow-up, the median stem subsidence relative to femur was -1.89 mm (range, -0.27 to -6.35), while the cement subsidence relative to femur was -0.06 mm (range, 0.44 to -0.55). There were 25 patients who were confirmed infection-free after the second stage revision with FIBG. The median Harris Hip Score improved from 51 pre-operatively to 79 at 5 years (P = .0130), and Harris Pain score from 20 to 40 (P = .0038). CONCLUSIONS: Stable femoral component fixation can be achieved with FIBG when reconstructing the femur after revision for infection without compromising infection cure rates and patient-reported outcomes.

EMG-Informed Neuromusculoskeletal Models Accurately Predict Knee Loading Measured Using Instrumented Implants.

OBJECTIVE: Using a musculoskeletal modelling framework, we aimed to (1) estimate knee joint loading using static optimization (SO); (2) explore different calibration functions in electromyogram (EMG)-informed models used in estimating knee load; and (3) determine, when using an EMG-informed stochastic method, if the measured joint loadings are solutions to the muscle redundancy problem when investigating only the uncertainty in muscle forces. METHODS: Musculoskeletal models for three individuals with instrumented knee replacements were generated. Muscle forces were calculated using SO, EMG-informed, and EMG-informed stochastic methods. Measured knee joint loads from the prostheses were compared to the SO and EMG-informed solutions. Root mean square error (RMSE) in joint load estimation was calculated, and the muscle force ranges were compared. RESULTS: The RMSE ranged between 192-674 N, 152-487 N, and 7-108 N for the SO, the calibrated EMG-informed solution, and the best fit stochastic result, respectively. The stochastic method produced solution spaces encompassing the measured joint loading up to 98% of stance. CONCLUSION: Uncertainty in muscle forces can account for total knee loading and it is recommended that, where possible, EMG measurements should be included to estimate knee joint loading. SIGNIFICANCE: This work shows that the inclusion of EMG-informed modelling allows for better estimation of knee joint loading when compared to SO.

RSA Measurements of Implant Instability in a Paprosky III Pelvic Defect with Discontinuity: A Case Report.

CASE: We report a case of acetabular reconstruction for a large defect with pelvic discontinuity that underwent 4 revisions for dislocations over a 3-year period. This allowed assessment of implant stability both on imaging, using measurements on plain radiographs and radiostereometric analysis (RSA) against both ilium and ischium, and direct assessment during each surgery. Only implant stability measured with RSA correlated with intraoperative revision findings. CONCLUSION: This case underlines the role of RSA in assessing early acetabular implant stability in pelvic discontinuity and the importance of assessing the stability of the implant against both ilium and ischium.

The variation in hip stability measurements between supine and standing radiographs of dysplastic hips.

AIMS: The aims of this study were to compare clinically relevant measurements of hip dysplasia on radiographs taken in the supine and standing position, and to compare Hip2Norm software and Picture Archiving and Communication System (PACS)-derived digital radiological measurements. METHODS: Preoperative supine and standing radiographs of 36 consecutive patients (43 hips) who underwent periacetabular osteotomy surgery were retrospectively analyzed from a single-centre, two-surgeon cohort. Anterior coverage (AC), posterior coverage (PC), lateral centre-edge angle (LCEA), acetabular inclination (AI), sharp angle (SA), pelvic tilt (PT), retroversion index (RI), femoroepiphyseal acetabular roof (FEAR) index, femoroepiphyseal horizontal angle (FEHA), leg length discrepancy (LLD), and pelvic obliquity (PO) were analyzed using both Hip2Norm software and PACS-derived measurements where applicable. RESULTS: Analysis of supine and standing radiographs resulted in significant variation for measurements of PT (p < 0.001) and AC (p = 0.005). The variation in PT correlated with the variation in AC in a limited number of patients (R2 = 0.378; p = 0.012). CONCLUSION: The significant variation in PT and AC between supine and standing radiographs suggests that it may benefit surgeons to have both radiographs when planning surgical correction of hip dysplasia. We also recommend using PACS-derived measurements of AI and SA due to the poor interobserver error on Hip2Norm. Cite this article: Bone Joint J 2021;103-B(11):1662-1668.

Clinical Characteristics, Etiology, and Initial Management Strategy of Newly Diagnosed Periprosthetic Joint Infection: A Multicenter, Prospective Observational Cohort Study of 783 Patients.

BACKGROUND: Periprosthetic joint infection (PJI) is a devastating complication of joint replacement surgery. Most observational studies of PJI are retrospective or single-center, and reported management approaches and outcomes vary widely. We hypothesized that there would be substantial heterogeneity in PJI management and that most PJIs would present as late acute infections occurring as a consequence of bloodstream infections. METHODS: The Prosthetic joint Infection in Australia and New Zealand, Observational (PIANO) study is a prospective study at 27 hospitals. From July 2014 through December 2017, we enrolled all adults with a newly diagnosed PJI of a large joint. We collected data on demographics, microbiology, and surgical and antibiotic management over the first 3 months postpresentation. RESULTS: We enrolled 783 patients (427 knee, 323 hip, 25 shoulder, 6 elbow, and 2 ankle). The mode of presentation was late acute (>30 days postimplantation and <7 days of symptoms; 351, 45%), followed by early (≤30 days postimplantation; 196, 25%) and chronic (>30 days postimplantation with ≥30 days of symptoms; 148, 19%). Debridement, antibiotics, irrigation, and implant retention constituted the commonest initial management approach (565, 72%), but debridement was moderate or less in 142 (25%) and the polyethylene liner was not exchanged in 104 (23%). CONCLUSIONS: In contrast to most studies, late acute infection was the most common mode of presentation, likely reflecting hematogenous seeding. Management was heterogeneous, reflecting the poor evidence base and the need for randomized controlled trials.

Acetabular Component Migration Measured Using Radiostereometric Analysis Following Revision Total Hip Arthroplasty: A Scoping Review.

* Radiostereometric analysis (RSA) studies of acetabular component migration following revision total hip arthroplasty (THA) have a large variation in their methodology and reporting of results, and, therefore, they may not be directly comparable. Standardization of RSA reporting is recommended. * In our review of RSA studies, there was a trend for cemented acetabular components to have larger amounts of early proximal migration than uncemented acetabular components. Results regarding cemented and uncemented components should be reported separately. * Cohorts that addressed larger acetabular defects were associated with a larger amount of early migration. * Reporting the migration result at 1 and 2 years postoperatively may enable earlier identification of poorly performing implants.

Acetabular avascular necrosis following high-dose steroid treatment and chemotherapy for leukemia : Computer tomography analysis of treatment with impaction bone grafting.

Avascular necrosis (AVN) of the bone is thought to be a serious complication of treatment for acute lymphoblastic leukemia (ALL). The acetabulum is an unusual area to be affected by AVN, and there are currently no reports of successful joint salvage procedures found in the literature. We present a case of a 20-year-old man with ALL who was diagnosed with debilitating AVN of both acetabula 2 years following initial diagnosis of ALL and treatment with a multi-agent chemotherapy regimen including high-dose corticosteroids. After unsuccessful treatment with bisphosphonate therapy, the acetabular AVN underwent bilateral curettage and impaction bone grafting to prevent collapse of subchondral fractures with the hope of salvaging both hip joints. Computer tomography (CT) of the AVN affected areas, pre- and post-bone impaction grafting, demonstrated healing of the subchondral fractures and a doubling of bone density that was maintained at 2 years after surgery. The patient resumed full weight-bearing at 3 months after first surgery, continues to ambulate unrestricted, and remains pain free 3 years post-surgery.

Structured-mentorship Program for Periacetabular Osteotomy Resulted in Few Complications for a Low-volume Pelvic Surgeon.

BACKGROUND: The Bernese periacetabular osteotomy (PAO) is a complex surgical procedure with a substantial learning curve. Although larger hospital and surgeon procedure volumes have recently been associated with a lower risk of complications, in geographically isolated regions, some complex operations such as PAO will inevitably be performed in low volume. A continuous structured program of distant mentoring may offer benefits when low numbers of PAOs are undertaken, but this has not been tested. We sought to examine a structured, distant-mentorship program of a low-volume surgeon in a geographically remote setting. QUESTIONS/PURPOSES: The purposes of this study were (1) to identify the clinical results of PAO performed in a remote-mentorship program, as determined by patient-reported outcome measures and complications of the surgery; (2) to determine radiographic results, specifically postoperative angular corrections, hip congruity, and progression of osteoarthritis; and (3) to determine worst-case analysis of PAO survivorship, defined as nonconversion to THA, in a regionally isolated cohort of patients with a high rate of followup. METHODS: Between August 1992 and August 2016, 85 PAOs were undertaken in 72 patients under a structured, distant-mentorship program. The patients were followed for a median of 5 years (range, 2-25 years). There were 18 males (21 hips) and 54 females (64 hips). The median age of the patients at the time of surgery was 26 years (range, 14-45 years). One patient was lost to followup (two PAOs) and one patient died as a result of an unrelated event. Patient-reported outcome measures and complications were collected through completion of patient and doctor questionnaires and clinical examination. Radiographic assessment of angular correction, joint congruity, and osteoarthritis was undertaken using standard radiology software. PAO survivorship was defined as nonconversion to THA and is presented using worst-case analysis. The loss-to-followup quotient-number of patients lost to followup divided by the number of a patients converted to THA-was calculated to determine quality of followup and reliability of survivorship data. RESULTS: The median preoperative Harris hip scores of 58 (range, 20-96) improved postoperatively to 78 (range, 33-100), 86 (range, 44-100), 87 (range, 55-97), and 80 (range, 41-97) at 1, 5, 10, and 14 years, respectively. Sink Grade III complications at 12 months included four relating to the PAO and one relating to the concomitant femoral procedure. The median lateral center-edge angle correction achieved was 22° (range, 3°-50°) and the median correction of acetabular index was 19° (range, 3°-37°). Osteoarthritis progressed from a preoperative mean Tönnis grade of 0.6 (median, 1; range, 0-2) to a postoperative mean of 0.9 (median, 1; range, 0-3). Six hips underwent conversion to THA: five for progression of osteoarthritis and one for impingement. At 12-year followup, survivorship of PAO was 94% (95% confidence interval [CI], 85%-98%) and survivorship with worst-case analysis was 90% (95% CI, 79%-96%). The loss-to-followup quotient for this study was low, calculated to be 0.3. CONCLUSIONS: When PAO is performed using a structured process of mentoring under the guidance of an expert, one low-volume surgeon in a geographically isolated region achieved good patient-reported outcomes, a low incidence of complications at 12 months, satisfactory radiographic outcomes, and high survivorship. A structured distant-mentorship program may be a suitable method for initially learning and continuing to perform low-volume complex surgery in a geographically isolated region. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Personalised 3D knee compliance from clinically viable knee laxity measurements: A proof of concept ex vivo experiment.

Personalised information of knee mechanics is increasingly used for guiding knee reconstruction surgery. We explored use of uniaxial knee laxity tests mimicking Lachman and Pivot-shift tests for quantifying 3D knee compliance in healthy and injured knees. Two healthy knee specimens (males, 60 and 88 years of age) were tested. Six-degree-of-freedom tibiofemoral displacements were applied to each specimen at 5 intermediate angles between 0° and 90° knee flexion. The force response was recorded. Six-degree-of-freedom and uniaxial tests were repeated after sequential resection of the anterior cruciate, posterior cruciate and lateral collateral ligament. 3D knee compliance (C6DOF) was calculated using the six-degrees-of-freedom measurements for both the healthy and ligament-deficient knees and validated using a leave-one-out cross-validation. 3D knee compliance (CCT) was also calculated using uniaxial measurements for Lachman and Pivot-shift tests both conjointly and separately. C6DOF and CCT matrices were compared component-by-component and using principal axes decomposition. Bland-Altman plots, median and 40-60th percentile range were used as measurements of bias and dispersion. The error on tibiofemoral displacements predicted using C6DOF was < 9.6% for every loading direction and after release of each ligament. Overall, there was good agreement between C6DOF and CCT components for both the component-by-component and principal component comparison. The dispersion of principal components (compliance coefficients, positions and pitches) based on both uniaxial tests was lower than that based on single uniaxial tests. Uniaxial tests may provide personalised information of 3D knee compliance.

Complications of trans arterial embolization during the resuscitation of pelvic fractures.

INTRODUCTION: Trans arterial embolization (TAE) can stem uncontrolled bleeding associated with pelvic fractures, but is associated with potential complications. This study investigated and compared the early to midterm complications in two patient cohorts: one who did and one who did not undergo TAE. METHODOLOGY: The results of 14 patients who underwent TAE in the resuscitation phase, and then had their pelvic fractures managed non-operatively, the study group (Group 1), were compared with those of a control group (Group 2) of 14 patients matched for age, sex, injury and management, that did not undergo TAE. All patients were examined clinically and answered a questionnaire on bowel and urinary function, pain and limp. Gluteus medius structure and volume were assessed on MRI. The hip girdle muscle function was assessed using a hand held dynamometer, surface electromyography as well as quantitative gait analysis. RESULTS: Seven patients in Group 1 (50%), but none in Group 2, had persistent urological dysfunctions, in the absence of any recognized previous pathology or urologic trauma at the time of injury. No gluteal muscle demonstrated fibrosis or fatty infiltration. The median gluteal muscle volume was not significantly decreased compared with the uninjured side in either group (P=0.421). The muscle strengths of gluteus maximus, gluteus medius, tensor fasciae latae and iliopsoas when compared to the uninjured side were significantly less in Group 1 compared to Group 2. However, no patient had a discernable limp and gait analysis showed no significant differences between the left and right sides in the study and control groups in the gluteal activation timing (p=0.171 and 0.354) and duration (p=0.622 and 0.435). There were no skin complications, and no patient reported any persistent bowel dysfunction. CONCLUSION: TAE was associated with a high rate of persistent urological dysfunction. TAE could lead to decreased hip muscles strength, however this does not seem to affect gait.

A new finding on the in-vivo crevice corrosion damage in a CoCrMo hip implant.

A detailed investigation was performed to characterize the fretting wear and corrosion damage to the neck component of a CoCrMo stem from a metal-on-polyethylene implant retrieved after 99months. The stem was a low-carbon (0.07wt%) wrought Co-28Cr-6Mo alloy with no secondary carbide phases in the matrix (γ-phase). The original design of the neck surface contained an intentionally fabricated knurled profile with a valley-to-peak range of approximately 11µm. Roughness measurements indicated that the tip of the knurled profile was significantly damaged, especially in the distal medial region of the neck, with up to a 22% reduction in the mean peak-to-valley height (Ra) compared to the original profile. As a new finding, the channels between the peaks of the profile created an additional crevice site in the presence of stagnant body fluid within the head-neck taper junction. These channels were observed to contain the most severe corroded areas and surface oxide layers with micro-cracks. SEM/EDS, XRD and XPS evaluations identified the formation of Cr2O3 as a corrosion product. Also, decobaltification was found to occur in these corroded areas. The findings of this work indicate the important role of the knurled profile in inducing additional crevice corrosion.

Confirmation of microevolutionary increase in spina bifida occulta among Swiss birth cohorts.

Previous studies on the prevalence of spina bifida occulta have indicated a microevolutionary increase in its frequency and possible population differences in the prevalence of the condition. We studied the frequencies of closed and open sacral canals at each sacral level among two birth cohorts in Switzerland. Transverse CT scans and multiplanar reconstruction images of sacra of 95 males and 96 females born in 1940-1950 and 99 males and 94 females born in 1970-1980 in Switzerland were reviewed. We found that individuals born later have significantly more open sacral arches at all sacral levels compared to those born 30-40 years earlier. When results were related to previously published data on Australian cohorts, the trend was the same, but Swiss in both cohorts were less likely to have an open section than Australians at all locations apart from S2. This study confirmed a microevolutionary trend in the opening of sacral canal among two different generations in Switzerland and demonstrated a population difference in the prevalence of spina bifida occulta.

Surviving multi-trauma in the past.

BACKGROUND: Surviving multi-trauma is strongly associated with emergent resuscitation and treatment in modern medical facilities. Multi-trauma survival before the advent of modern medicine is likely to have been extremely uncommon, particularly in primitive societies. The aim of this study was to investigate the case of an ancient Australian Aboriginal who appeared to have survived multi-trauma. METHODS: We investigated the skeletal remains of an adult Australian Aboriginal with healed fractures of the right femur and humerus. The time of death was assessed by carbon dating. The sex and approximate age of the subject were assessed from the skeleton's morphometry. The fractured bones were assessed by visual inspection, plain radiographs and computer tomography (CT) scanning. RESULTS: The remains were of a male aged approximately 50 years at the time of his death, approximately 1000 years ago, preceding European settlement. Analysis of the malunions indicated that all fractures occurred in one traumatic event, normally a life-threatening injury combination, and that the subject survived for years after this incident, despite no or failed active treatment of his fractures. CONCLUSIONS: The survival of a man living in a primitive society after multi-trauma reflects an impressive depth of nursing and social support in a community of hunter gatherers.

Secular trend in the opening of the sacral canal: an Australian study.

STUDY DESIGN: Computer tomography scans were used to asses the opening of the sacral canal. OBJECTIVE: We investigated the prevalence of sacral spina bifida occulta in 2 population groups: born 1940 to 1950 and 1980 to 1990. SUMMARY OF BACKGROUND DATA: Comparison of the prevalence of spina bifida occulta in the first-century Pompeii with that in 20th century European and Mediterranean populations indicates that the degree of the closure of vertebral arches in the sacrum has undergone changes and the prevalence of spina bifida occulta is increasing. METHODS: Transverse computer tomograph scans and multiplanar reconstruction images of sacra of 100 males and 100 females born 1940 to 1950 and 100 males and 100 females born 1980 to 1990 were used after ethics committee approval. RESULTS: The individuals born later have significantly more open sacral arches when compared with those born 40 years earlier, especially in the midsacral region. Also, males have open sacral arches in the rostral segments of the sacrum more than females. CONCLUSION: This study demonstrates a secular trend in the opening of the sacral canal in both sexes that occurred within 2 generations. Also, the increased prevalence of open sacral canal in males suggests a different response between sexes to the forces of evolution.