Radiological outcome of hallux valgus deformity correction with metatarsal osteotomy from a single-center cohort - Best results achieved by foot and ankle surgeons

BACKGROUND

To evaluate the radiological outcome, especially undercorrection of hallux valgus deformity correction with first metatarsal osteotomy.

PATIENTS AND METHODS

439 1st metatarsal osteotomies including 241 distal (55 %), 175 midshaft (40 %), and 23 proximal (5 %) were available for analysis with median follow-up time was 48 days (range 27-990 days).

RESULTS

The postoperative HVA was normal in 237 (54 %), mild in 110 (25 %), moderate in 87 (20 %), and severe in 5 (1 %) of the cases. BMI (p = 0.0127), sex (p = 0.0004), preoperative HVA (p = 0.0028), and surgeons experience (p < 0.0001) were associated with radiological outcome, whereas age, hospital, and type of osteotomy had no effect. Foot and ankle surgeons achieved normal postoperative HVA in 76 %, general orthopedic surgeons in 41 %, and residents in 47 % of the operations.

CONCLUSION

Radiological undercorrection was common. As foot and ankle surgeons achieved best radiological correction, hallux valgus deformity should be operated by specialists.

Bioactive glass granules versus standard autologous and allogeneic bone grafts: a randomized trial of 49 adult bone tumor patients with a 10-year follow-up

BACKGROUND AND PURPOSE

As a synthetic bone void filler, bioactive glasses (BGs) may enhance angiogenesis and osteogenesis. In this randomized trial, we compared the clinical efficacy of BG granules and standard bone grafts in patients undergoing surgery for benign bone tumors.

PATIENTS AND METHODS

49 recruited patients were randomized to receive BG granules or undergo conventional bone grafting to fill defects following tumor removal. As the standard of care, small-sized defects were filled with autologous graft, and large-sized defects were filled with allogeneic graft. The primary endpoint was treatment success at 1 year, defined by no reoperation, no tumor recurrence, and no device-related adverse events. Secondary endpoints included patient-reported outcomes (Rand-36 and pain scores) and quantitative assessment of blood flow and metabolic activity by means of 18F-fluoride PET/CT imaging. As an off-trial group, 15 children and adolescents (age < 18 years) underwent tumor removal and BG-filling, without randomization.

RESULTS

At 1-year, 21 of 25 BG-treated patients (risk estimate 0.84, 95% confidence interval [CI] 0.70-0.98) and 20 of 24 patients in the standard of care group (0.83, CI 0.68-0.98) met the criteria for treatment success. The groups had similar Rand-36 scores. In patients with small defects, BG filling was associated with shorter operative time and less postoperative pain at 1 month. In patients with large defects, blood flow was similar, but BG-filled defects showed higher metabolic activity than allograft-filled defects at 1-year. The survey of the postoperative period ≥10 years revealed no BG-related adverse events.

INTERPRETATION

BG granules had similar overall rates of treatment success compared with autografts and allografts, but large-scale trials are needed for the confirmation of clinical equivalence. The extended metabolic activity confirms the expected cellular responses of osseointegrated BG granules.

68Ga-Citrate Positron Emission Tomography of Healthy Men: Whole-Body Biodistribution Kinetics and Radiation Dose Estimates

⁶⁸Ga-citrate has one of the simplest chemical structures of all ⁶⁸Ga-radiopharmaceuticals, and its clinical use is justified by the proven medical applications using its isotope-labeled compound ⁶⁷Ga-citrate. To support broader application of ⁶⁸Ga-citrate in medical diagnosis, further research is needed to gain clinical data from healthy volunteers. In this work, we studied the biodistribution of ⁶⁸Ga-citrate and subsequent radiation exposure from it in healthy males. Methods: ⁶⁸Ga-citrate was prepared with an acetone-based radiolabeling procedure compliant with Good Manufacturing Practices. Six healthy males (age 41 ± 12 years, mean ± SD) underwent sequential whole-body PET/CT scans after an injection of 204 ± 8 MBq of ⁶⁸Ga-citrate. Serial arterialized venous blood samples were collected during PET imaging and the radioactivity concentration was measured with a gamma counter. Urinary voids were collected and measured. The Medical Internal Radiation Dose (MIRD) bladder-voiding model with a 3.5 hour voiding interval was used. A model using a 70 kg adult male and MIRD schema was used to estimate absorbed doses in target organs and effective doses. Calculations were performed using OLINDA/EXM 2.0 software. Results: Radioactivity clearance from the blood was slow, and relatively high radioactivity concentrations were observed over the whole of the 3 hour measuring period. Although radioactivity excretion via urine was rather slow (biological half-time, 69 ± 24 hours), the highest decay-corrected concentrations in urinary bladder contents were measured at 90 and 180 minute time points. Moderate concentrations were also seen in kidneys, liver, and spleen. The source organs showing the largest residence times were muscle, liver, lung, and heart contents. The heart wall received the highest absorbed dose of 0.077 ± 0.008 mSv/MBq. The mean effective dose (ICRP 103) was 0.021 ± 0.001 mSv/MBq. Conclusion: PET imaging with ⁶⁸Ga-citrate is associated with modest radiation exposure. A 200 MBq injection of ⁶⁸Ga-citrate results in an effective radiation dose of 4.2 mSv, which is in the same range as other ⁶⁸Ga-labeled tracers. This suggests the feasibility of clinical studies using ⁶⁸Ga-citrate imaging in humans and the possibility of performing multiple scans in the same subjects across the course of a year.

Long-term blood metal ion levels and clinical outcome after Birmingham hip arthroplasty

BACKGROUND AND OBJECTIVE

Our aim was to assess long-term metal ion level changes and clinical outcome in patients with a Birmingham hip arthroplasty.

METHODS

For the purpose of this study, we identified all BHR hip resurfacing arthroplasty (HRA) and total hip arthroplasty (THA) operations performed in Turku University Hospital. A random coefficient model was used to compare the change between the first and last metal ion measurement. A Kaplan-Meier estimator was used to assess the survivorship of the BHR HRA and BHR THA with metal related adverse events (pseudotumor, elevated metal ions above the safe upper limit, revision due to metallosis), or revision due to any reason as endpoints with 95% confidence intervals (CIs).

RESULTS

BHR HRA was used in 274 hips (233 patients). In addition, we identified 38 BHR-Synergy THAs (38 patients). Operations were performed between 2003 and 2010. Median follow-up time was 14 years for BHR HRA (range: 0.6-17) and 11 years for BHR THA (range: 4.7-13). In the BHR HRA group, geometric means of Cr and Co levels decreased from 2.1 to 1.6 ppb and 2.4 to 1.5 ppb, respectively, during a 3.0-year measurement interval. Metal ion levels in the BHR THA group did not show notable increase. The survivorship of BHR HRA was 66% in 16 years and 34% for BHR THA at 12 years for any metal-related adverse event.

CONCLUSIONS

Patients with a Birmingham hip device do not seem to benefit from frequent repeated metal ion measurements. The amount of patients with metal-related adverse events was relatively high, but many of them did not require surgery.

Return to work after lumbar disc herniation surgery: an occupational cohort study

Background and purpose - Lumbar disc herniation is a common surgically treated condition in the working-age population. We assessed health-related risk factors for return to work (RTW) after excision of lumbar disc herniation. Previous studies on the subject have had partly contradictory findings.Patients and methods - RTW of 389 (n = 111 male, n = 278 female; mean age 46 years, SD 8.9) employees who underwent excision of lumbar disc herniation was assessed based on the Finnish Public Sector Study (FPS). Baseline information on occupation, preceding health, and health-risk behaviors was derived from linkage to national health registers and FPS surveys before the operation. The likelihood of RTW was analyzed using Cox proportional hazard univariable and multivariable modelling.Results - 95% of the patients had returned to work at 12 months after surgery, after on average 78 days of sickness absence. Faster RTW in the univariable Cox model was associated with a small number of sick leave days (< 30 days) before operation (HR 1.3, 95% CI 1.1-1.6); high occupational position (HR 1.6, CI 1.2-2.1); and age under 40 years (HR 1.5, CI 1.1-1.9). RTW was not associated with sex or the health-related risk factors obesity, physical inactivity, smoking, heavy alcohol consumption, poor self-rated health, psychological distress, comorbid conditions, or purchases of pain or antidepressant medications in either the univariable or multivariable model.Interpretation - Almost all employees returned to work after excision of lumbar disc herniation. Older age, manual job, and prolonged sick leave before the excision of lumbar disc herniation were risk factors for delayed return to work after the surgery.

First-in-Humans Study of 68Ga-DOTA-Siglec-9, a PET Ligand Targeting Vascular Adhesion Protein 1

Sialic acid–binding immunoglubulinlike lectin 9 (Siglec-9) is a ligand of vascular adhesion protein 1. A ⁶⁸Ga-labeled peptide of Siglec-9, ⁶⁸Ga-DOTA-Siglec-9, holds promise as a novel PET tracer for imaging of inflammation. This first-in-humans study investigated the safety, tolerability, biodistribution, and radiation dosimetry of this radiopharmaceutical. Methods: Six healthy men underwent dynamic whole-body PET/CT. Serial venous blood samples were drawn from 1 to 240 min after intravenous injection of 162 ± 4 MBq of ⁶⁸Ga-DOTA-Siglec-9. In addition to γ-counting, the plasma samples were analyzed by high-performance liquid chromatography to detect intact tracer and radioactive metabolites. Radiation doses were calculated using the OLINDA/EXM software, version 2.2. In addition, a patient with early rheumatoid arthritis was studied with both ⁶⁸Ga-DOTA-Siglec-9 and ¹⁸F-FDG PET/CT to determine the ability of the new tracer to detect arthritis. Results:⁶⁸Ga-DOTA-Siglec-9 was well tolerated by all subjects. ⁶⁸Ga-DOTA-Siglec-9 was rapidly cleared from the blood circulation, and several radioactive metabolites were detected. The organs with the highest absorbed doses were the urinary bladder wall (0.38 mSv/MBq) and kidneys (0.054 mSv/MBq). The mean effective dose was 0.022 mSv/MBq (range, 0.020–0.024 mSv/MBq). Most importantly, however, ⁶⁸Ga-DOTA-Siglec-9 was comparable to ¹⁸F-FDG in detecting arthritis. Conclusion: Intravenous injection of ⁶⁸Ga-DOTA-Siglec-9 was safe and biodistribution was favorable for testing of the tracer in larger group of patients with rheumatoid arthritis, as is planned for the next phase of clinical trials. The effective radiation dose of ⁶⁸Ga-DOTA-Siglec-9 was within the same range as the effective radiation doses of other ⁶⁸Ga-labeled tracers. Injection of 150 MBq of ⁶⁸Ga-DOTA-Siglec-9 would expose a subject to 3.3 mSv. These findings support the possible repeated clinical use of ⁶⁸Ga-DOTA-Siglec-9, such as in trials to elucidate the treatment efficacy of novel drug candidates.

Repeated cobalt and chromium ion measurements in patients with bilateral large-diameter head metal-on-metal ReCap-M2A-Magnum total hip replacement

Background and purpose - Whole-blood (WB) chromium (Cr) and cobalt (Co) measurements are vital in the follow-up of metal-on-metal total hip replacement (MoM THR) patients. We examined whether there is a substantial change in repeated WB, Co, and Cr levels in patients with bilateral ReCap-M2A-Magnum THR. We also specified the number of patients exceeding the safe upper limit (SUL) of WB Co and Cr in the repeated measurement.Patients and methods - We identified 141 patients with bilateral ReCap-M2A-Magnum THR operated in our institution. 61 patients had repeated WB metal ion measurements with bilateral MoM implants still in situ in the second measurement. The mean time elapsing from the first measurement (initial measurement) to the second (control measurement) was 1.9 years (SD = 0.6, range 0.2-3.5). We used earlier established SUL levels for bilateral implants by Van Der Straeten et al. (2013).Results - The median (range) Co and Cr values decreased in the repeated measurement from 2.7 (0.6-25) to 2.1 (0.5-21) and 2.6 (0.8-14) to 2.1 (0.5-18) respectively. In 13% of the patients Co levels exceeded the SUL in the initial measurement and the proportion remained constant, at 13%, in the repeated measurement. In 5% of the patients, Cr levels were above SUL in the initial measurement and an equal 5% in the control measurement.Interpretation - Repeated WB metal ion levels did not increase in patients with bilateral ReCap-M2A-Magnum THR with a mean 1.9-year measurement interval. Long-term development of WB metal ion levels is still unclear in these patients.

Local anesthetic pain catheters to reduce opioid use in massive weight loss patients undergoing abdominoplasty: A comparative study

BACKGROUND

Abdominoplasty is a common procedure for anatomical restoration of the lower abdominal skin, with a continuously increasing annual number of procedures performed. The significance of postoperative pain management is of crucial importance from a patient's perspective and to ensure the achievement of the aimed clinical outcome. We evaluated the efficacy of local pain pump catheters (PPCs) on massive weight loss patients undergoing body-contouring abdominoplasty.

METHODS

Primary abdominoplasty procedures after massive weight loss performed from 2009 to 2014 were retrospectively reviewed. The patients were divided into two groups according to the use of the PPC. The primary outcome measure was the amount of opioid use calculated as morphine equivalents. The secondary outcome measures were the length of hospital stay (LOS) and early postoperative complications within 30 days of surgery.

RESULTS

A total of 61 patients were included in the study: 24 patients in the PPC group and 37 patients in the conventional abdominoplasty analgesia (CAA) group. No significant differences between the study groups were found with regard to demographics, operative time, and resection weight. A significantly decreased use of opioids was observed after using PPC versus control (14.0 ± 13.9 mg vs. 74.6 ± 73.3 mg, p < 0.001). Similarly, the LOS was shorter in the PPC group (3.1 ± 1.1 days vs. 3.8 ± 1.0 days, p = 0.023). There was a similar rate of complications in both groups (45.8% vs. 40.5%, p = 0.622). The most common complication was seroma formation (25.0% vs. 18.5%, p = 0.315).

CONCLUSION

The use of local anesthetic pain catheters in abdominoplasty may be associated with a decreased use of opioids and might result in a shorter hospital stay on massive weight loss patients. Further studies are needed to validate this treatment modality.

Are patient-related pre-operative factors influencing return to work after total knee arthroplasty

BACKGROUND

Osteoarthritis is one of the leading causes of disability in working-age patients. The total number of working-age patients undergoing total-knee arthroplasty (TKA) is continuously increasing. The purpose of this study was to identify predictive factors related to general health, health risk behaviors and socioeconomic status influencing the rate of return to work after a TKA.

METHODS

Overall there were 151,901 patients included in the Finnish Public Sector (FPS) study. The response rate varied between 65 and 73% during the study period. We used Cox proportional hazard models to examine patient-related predictive factors that may influence the rate of return to work after TKA in a cohort of patients (n = 452; n = 362 female; mean age 56.4 years). Predictive factors were measured on average 3.6 years before the operation.

RESULTS

Of the patients, 87% returned to work within one year after TKA at a mean of 116 calendar days. In multivariate analysis, patients at sick-leave ≤30 days during the last year before surgery were 2.2 times (95% confidence interval 1.72-2.92) more likely to return to work compared with those with >30 days of sick-leave. Compared with patients in manual work, those in higher or lower level non-manual work showed a 2.6-fold (1.95-3.52) and 1.5-fold (1.15-1.92) increased probability of returning to work. Age, sex, health risk behaviors, obesity, physical comorbidities, common mental disorders, and other studied health-related factors were not associated with the rate of return to work.

CONCLUSIONS

Non-manual job, good self-rated general health and preoperative sick leave ≤30 days are associated with a higher rate of return to work.

Return to work after primary total hip arthroplasty: a nationwide cohort study

Background and purpose - While the number of working-age patients undergoing total hip arthroplasty (THA) is increasing, the effect of the surgery on patients' return to work (RTW) is not thoroughly studied. We aimed to identify risk factors of RTW after THA among factors related to demographic variables, general health, health risk behaviors, and socioeconomic status. Patients and methods - We studied 408 employees from the Finnish Public Sector (FPS) cohort (mean age 54 years, 73% women) who underwent THA. Information on demographic and socioeconomic variables, preceding health, and health-risk behaviors was derived from linkage to national health registers and FPS surveys before the operation. The likelihood of return to work was examined using Cox proportional hazard modeling. Results - 94% of the patients returned to work after THA on average after 3 months (10 days to 1 year) of sickness absence. The observed risk factors of successful return to work were: having < 30 sick leave days during the last year (HR 1.8; 95% CI 1.4-2.3); higher occupational position (HR 2.2; CI 1.6-2.9); and BMI < 30 (HR 1.4; CI 1.1-1.7). Age, sex, preceding health status, and health-risk behaviors were not correlated with RTW after the surgery. Interpretation - Most employees return to work after total hip arthroplasty. Obese manual workers with prolonged sick leave before the total hip replacement were at increased risk of not returning to work after the surgery.

Repeated cobalt and chromium ion measurements in patients with large-diameter head metal-on-metal ReCap-M2A-Magnum total hip replacement

Background and purpose - Whole blood (WB) cobalt (Co) and chromium (Cr) ion levels have a major role in the follow-up of metal-on-metal total hip replacement (MoM THR). We investigated, first, if there was a change in WB Co or Cr levels over repeated measurements in patients with ReCap-M2A-Magnum THR, and, second, determined how many patients had WB Co or Cr levels that exceeded the safe upper limits (SUL) in the repeated whole blood metal ion assessment. Patients and methods - A Recap-M2A-Magnum THR was used in 1,329 operations (1,188 patients) at our institution between 2005 and 2012. We identified all patients (n = 319) with unilateral ReCap-M2A-Magnum implants who had undergone at least 2 repeated metal ion measurements with the first blood sample taken mean 5.5 years (1.8-9.3) after surgery and the second taken mean 2 years (0.5-3) after the first. Results - The median WB Co and Cr ion levels decreased in repeated measurements from 1.40 (0.40-63) ppb to 1.10 (0.20-68) ppb and from 1.60 (0.60-13.0) ppb to 1.10 (0.30-19.0) ppb, respectively. 7% of the Co ion values exceeded SUL at the initial measurement, and 7% at the control measurement. The proportion of Cr ion values exceeding the safe upper limit (SUL) decreased during the measurement interval from 5% to 4%. Interpretation - Repeated metal ion measurements in unilateral ReCap-M2A-Magnum patients in a mean 2-year time interval did not show any increase. Long-term ion levels are, however, not yet known.

A Meta-analysis On Evidence Of Platelet-rich Plasma for Androgenetic Alopecia

Background:

Platelet-rich plasma (PRP) treatment has gained popularity among different surgical specialities for improving various conditions. Androgenetic alopecia (AGA) is a common disorder, with possible psychosocial implications. Plastic surgeons have increased the practice of PRP injections for hair restoration. A meta-analysis on this topic was performed comparing local injection of PRP versus control to investigate the efficacy of local PRP injections in AGA.

Methods:

We performed a systematic literature search. The increase in number of hairs was the primary outcome. Secondary outcomes were the increase of hair thickness and the percentage increase in hair number and thickness.

Results:

Seven studies involving 194 patients were retrieved and included in the present analysis. A significantly locally increased hair number per cm² was observed after PRP injections versus control (mean difference [MD] 14.38, 95% confidence interval [CI] 6.38–22.38, P < 0.001). Similarly, a significantly increased hair thickness cross-section per 10⁻⁴ mm² (MD 0.22, 95% CI 0.07–0.38, P = 0.005) favoring PRP group. The pooled results did not show a significant percentage increase in hair number (MD 18.79%, 95% CI − 8.50–46.08, P = 0.18), neither hair thickness (MD 32.63%, 95% CI − 16.23–81.48, P = 0.19) among patients treated with PRP.

Conclusion:

Local injection of PRP for androgenic alopecia might be associated with an increased number of hairs in the treated areas with minimal morbidity, but there is clearly a lack of scientific evidence on this treatment modality. Further studies are needed to evaluate the efficacy of PRP for AGA.

Platelet-rich plasma for androgenetic alopecia: Does it work? Evidence from meta analysis

INTRODUCTION

The use of platelet-rich plasma (PRP) has increased among different surgical specialities for the treatment of various conditions. Androgenetic alopecia is a common condition, with severe attendant psychosocial implications. PRP injections for hair restoration have become a popular practice among plastic surgeons. We performed a meta-analysis comparing local injection of platelet-rich plasma versus control to evaluate this issue in order to investigate the effectiveness of PRP local injections for androgenetic alopecia.

METHODS

A systematic literature search was performed. Primary outcome was the increase in number of hairs. Secondary outcomes were the increase in hair thickness and the percentage increase in hair number and thickness. We performed random-effect analysis.

RESULTS

Six studies involving 177 patients were retrieved and included in the present analysis. A significantly locally increased hair number per cm² was observed after PRP injections versus control (mean difference (MD) 17.90, 95%CI 5.84-29.95, P=.004). Similarly, a significantly increased hair thickness cross section per 10^-4  mm² (MD 0.22, 95%CI 0.07-0.38, P=.005) favoring PRP group. The pooled results did not show statistically significant differences in percentage increase in hair number (MD 24.12%, 95%CI -12.76-60.99, P=.20) and hair thickness (MD 32.63%, 95%CI -16.23-81.48, P=0.19) among patients treated with PRP.

CONCLUSIONS

Local injection of PRP for androgenic alopecia might be associated with an increased number of hairs and some hair thickness improvement in the treated areas with minimal morbidity. The results of this meta-analysis should be interpreted with caution as it consists of pooling many small studies. Larger randomized studies can verify this perception.

Systematic Screening of Adverse Reactions to Metal Debris after Recap-M2A-Magnum Metal-on-Metal Total Hip Arthroplasty

Background and Aims:

An adverse reaction to metal debris is a known complication after large diameter head metal-on-metal total hip arthroplasty. However, the failure rate varies depending on the implant design. Therefore, we investigated the prevalence of adverse reaction to metal debris, as well as the symptoms and risk factors after undergoing a ReCap-M2a-Magnum large diameter head metal-on-metal total hip arthroplasty.

Materials and Methods:

Between 2005 and 2012, 1188 patients (1329 hips) underwent ReCap-M2a-Magnum total hip arthroplasty at our institution. Systematic screening for adverse reaction to metal debris was arranged using the Oxford Hip Score questionnaire, hip and pelvic radiographs, and assessments of the serum chromium and cobalt ion levels. Clinical evaluation and magnetic resonance imaging were performed for the symptomatic patients, as well as those with either chromium or cobalt ion levels ⩾5 µg/L. The prevalence of adverse reaction to metal debris after ReCap-M2a-Magnum total hip arthroplasty was assessed, and the risk factors for adverse reaction to metal debris were evaluated using logistic regression. The mean follow-up time was 5.2 (0.003–9.1) years. This study was an extension of a previous study conducted at our institution with 80 patients.

Results:

In total, 33 patients (33 hips, 2.5% of all hips) required a revision operation due to adverse reaction to metal debris. Moreover, 157 hips exhibited definitive adverse reaction to metal debris, but a revision operation was not performed (157 of 1329 hips, 11.8% of all hips). Overall, 190 out of 1329 (14.3%) hips had definitive adverse reaction to metal debris. Pain, subluxation sensation, clicking, swelling, a small head size, and a fair/poor Oxford Hip Score were associated with definitive adverse reaction to metal debris.

Conclusion:

We found a high prevalence of adverse reaction to metal debris in the ReCap-M2a-Magnum total hip arthroplasty patients in this study; however, most of the patients did not require revision operations.

Independence of Genetic Geographical Variation between Photoperiodic Diapause, Circadian Eclosion Rhythm, and Thr-Gly Repeat Region of the Period Gene in Drosophila littoralis

Drosophila littoralis is a latitudinally widespread European species of the Drosophila virilis group. The species has ample genetic variation in photoperiodism (adult diapause) and circadian rhythmicity (pupal eclosion rhythm), with adaptive latitudinal clines in both of them. The possible common genetic basis between the variability of photoperiodism and circadian rhythms was studied by a long-term crossing experiment. A northern strain (65 °N) having long critical day length (CDL = 19.9 h) for diapause, early phase of the entrained rhythm in LD 3:21 (ψLD3:21 = 12.3 h), and short period (τ= 18.8 h) of the free-running rhythm for the eclosion rhythm was crossed with a southern strain (42 °N) having short CDL (12.4 h), late eclosion phase (ψLD3:21 = 20.2 h), and long period (τ= 22.8 h). After 54 generations, including free recombination, artificial selection, and genetic drift, a novel strain resulted, having even more “southern” diapause and more “northern” eclosion rhythm characteristics than found in any of the geographical strains. The observed complete separation of eclosion rhythm characteristics from photoperiodism is a new finding in D. littoralis; in earlier studies followed for 16 generations, the changes had been mostly parallel. Evidently, the genes controlling the variability of the eclosion rhythm and photoperiodism in D. littoralis are different but closely linked. To test for the possible gene loci underlying the observed geographical variability, the period gene was studied in 10 strains covering all the known clock variability in D. littoralis. The authors sequenced the most suspected Thr-Gly region, which is known to take part in the adaptive clock variability in Drosophila melanogaster. No coding differences were found in the strains, showing that this region is not included in the adaptive clock variability in D. littoralis.

68Ga-DOTA-Siglec-9--a new imaging tool to detect synovitis

Introduction

Vascular adhesion protein-1 (VAP-1) is an adhesion molecule, which upon inflammation is rapidly translocated from intracellular sources to the endothelial cell surface. We have recently discovered that sialic acid- binding immunoglobulin-like lectin 9 (Siglec-9) is a leukocyte ligand of VAP-1 and that ⁶⁸Ga-labeled Siglec-9 motif peptide facilitates in vivo imaging of inflammation. This study evaluated the feasibility of ⁶⁸Ga-DOTA-Siglec-9 positron emission tomography (PET) for the assessment of synovitis.

Methods

Rabbits with synovial inflammation were injected with ¹⁸F-FDG or ⁶⁸Ga-DOTA-Siglec-9 and studied by gamma counting and autoradiography. Certain rabbits were also examined with magnetic resonance imaging (MRI). After PET imaging, rabbits were intravenously administered with anti-VAP-1 antibody to evaluate luminal expression of VAP-1 by immunohistochemistry. Finally, binding of Siglec-9 peptide and VAP-1 positive vessels were evaluated by double staining of rheumatoid arthritis synovium.

Results

Intra-articular injection of hemagglutinin induced mild synovial inflammation in rabbit knee with luminal expression of VAP-1. Synovitis was clearly visualized by ⁶⁸Ga-DOTA-Siglec-9 PET in addition to ¹⁸F-FDG-PET and MRI. Compared with the ¹⁸F-FDG, the ex vivo inflamed-to-control synovium ratio of ⁶⁸Ga-DOTA-Siglec-9 was similar (1.7 ± 0.4 vs. 1.5 ± 0.2, P = 0.32). Double staining revealed that Siglec-9 peptide binds to VAP-1 positive vessels in human rheumatoid synovium.

Conclusion

Ga-DOTA-Siglec-9 PET tracer detected VAP-1 positive vasculature in the mild synovitis of rabbits comparable with ¹⁸F-FDG, suggesting its potential for in vivo imaging of synovial inflammation in patients with rheumatic diseases.

[Treatment of posterior cruciate ligament injury in skeletally immature patients]

Posterior cruciate ligament tear is a rare injury in the pediatric and adolescent population. Primary diagnosis of posterior cruciate ligament injury is based on careful attention to specific physical examination, but MRI is the mainstay for assessing the extent of ligamentous and possible associated injuries. In general, most of the posterior cruciate ligament tears in children and adolescents can be treated non-operatively with good functional outcome. Surgical treatment for these injuries should however be cautiously considered also for skeletally immature patients with a complete, intrasubstance ligament tear or dislocated avulsion fracture.

A comparative 18F-FDG PET/CT imaging of experimental Staphylococcus aureus osteomyelitis and Staphylococcus epidermidis foreign-body-associated infection in the rabbit tibia

Background

¹⁸F-FDG-PET imaging has emerged as a promising method in the diagnosis of chronic osteomyelitis commonly due to Staphylococcus aureus. The inaccuracy of ¹⁸ F-FDG-PET in the detection of periprosthetic joint infections may be related to the predominance of low-virulent S. epidermidis strains as the causative pathogen. We have compared the¹⁸F-FDG-PET characteristics of S. aureus osteomyelitis and foreign-body-associated S. epidermidis infections under standardized laboratory conditions.

Methods

Twenty-two rabbits were randomized into three groups. In group 1, a localized osteomyelitis model induced with a clinical strain of S. aureus was applied. In groups 2 and 3, a foreign-body-associated infection model induced with a clinical or laboratory strain of S. epidermidis was applied. A small block of bone cement was surgically introduced into the medullary cavity of the proximal tibia followed by peri-implant injection of S. aureus (1 × 10⁵ CFU/mL) or one of the two S. epidermidis (1 × 10⁹ CFU/mL) strains with an adjunct injection of aqueous sodium morrhuate. In group 1, the cement block was surgically removed at 2 weeks but left in place in groups 2 and 3 in order to mimic foreign-body-associated S. epidermidis infections. At 8 weeks, the animals were imaged using ¹⁸ F-FDG PET/CT. The presence of bacterial infection was confirmed by cultures, and the severity of bone infections was graded by means of radiography, peripheral quantitative CT, and semi-quantitative histology.

Results

The S. aureus strain caused constantly culture-positive osteomyelitis. The clinical S. epidermidis strain resulted in foreign-body-associated infections, while the laboratory S. epidermidis strain (ATCC 35983) induced only occasionally culture-positive infections. There was a correlation (r = 0.645; P = 0.013) between semi-quantitative score of leukocyte infiltration and the ¹⁸ F-FDG uptake in animals with positive cultures. Standardized uptake value (SUV) of the infected bones was twofold (P < 0.001) in S. aureus animals compared with S. epidermidis animals, but there was only a trend (P = 0.053, ANOVA) in the differences of the corresponding SUV ratios. This was due to the altered ¹⁸ F-FDG uptake of the contralateral tibias probably reflecting a systemic impact of severe osteomyelitis.

Conclusion

The peri-implant inoculation of S. epidermidis, reflecting low virulence of the pathogen and limited leukocyte infiltration, was characterized by low ¹⁸ F-FDG uptake.

Low BMD affects initial stability and delays stem osseointegration in cementless total hip arthroplasty in women: a 2-year RSA study of 39 patients

BACKGROUND AND PURPOSE

Immediate implant stability is a key factor for success in cementless total hip arthroplasty (THA). Low bone mineral density (BMD) and age-related geometric changes of the proximal femur may jeopardize initial stability and osseointegration. We compared migration of hydroxyapatite-coated femoral stems in women with or without low systemic BMD.

PATIENTS AND METHODS

61 female patients with hip osteoarthritis were treated with cementless THA with anatomically designed hydroxyapatite-coated femoral stems and ceramic-ceramic bearing surfaces (ABG-II). Of the 39 eligible patients between the ages of 41 and 78 years, 12 had normal systemic BMD and 27 had osteopenia or osteoporosis. According to the Dorr classification, 21 had type A bone and 18 had type B. Translational and rotational migration of the stems was evaluated with radiostereometric analysis (RSA) up to 2 years after surgery.

RESULTS

Patients with low systemic BMD showed higher subsidence of the femoral stem during the first 3 months after surgery than did those with normal BMD (difference = 0.6, 95% CI: 0.1-1.1; p = 0.03). Low systemic BMD (odds ratio (OR) = 0.1, CI: 0.006-1.0; p = 0.02), low local hip BMD (OR = 0.3, CI: 0.1-0.7; p = 0.005) and ageing (OR = 1.1, CI: 1.0-1.2; p = 0.02) were risk factors for delayed translational stability. Ageing and low canal flare index were risk factors for delayed rotational stabilization (OR = 3, CI: 1.1-9; p = 0.04 and OR = 1.1, CI: 1.0-1.2; p = 0.02, respectively). Harris hip score and WOMAC score were similar in patients with normal systemic BMD and low systemic BMD.

INTERPRETATION

Low BMD, changes in intraosseous dimensions of the proximal femur, and ageing adversely affected initial stability and delayed osseointegration of cementless stems in women.

Quality of intertrochanteric cancellous bone as predictor of femoral stem RSA migration in cementless total hip arthroplasty

In cementless total hip arthroplasty, osteoporosis may jeopardize the achievement of immediate stability and lead to migration of anatomically shaped femoral stems. Poor quality of proximal cancellous bone per se may also affect the rate of osseointegration. In a selected group of female total hip arthroplasty patients (mean age 64 years) with unremarkable medical history, intertrochanteric cancellous bone biopsy was taken from the site of stem implantation. Local bone quality, determined by structural μCT imaging and destructive compression testing of the biopsy tissue, was used as the predictor of three-dimensional stem migration determined by radiostereometric analysis (RSA) up to 24 months. The patients exhibited major differences in mechanical properties of the intertrochanteric cancellous bone, which were closely related to the structural parameters calculated from μCT data. Unexpectedly, the major differences observed in the quality of trochanteric cancellous bone had only minor reflections in the RSA migration of the femoral stems. In statistical analysis, the μCT-based bone mineral density quartile (low, middle, high) was the only significant predictor for stem translation at 24 months (p=0.022) but only a small portion (R(2)=0.16) of the difference in translation could be explained by changes in bone mineral density quartile. None of the other parameters investigated predicted stem migration in translation or rotation. In conclusion, poor quality of intertrochanteric cancellous bone seems to contribute to the risk of implant migration less than expected. Probably also the importance of surgical preservation of intertrochanteric cancellous bone has been over-emphasized for osseointegration of cementless stem.

Synthesis, 68Ga labeling and preliminary evaluation of DOTA peptide binding vascular adhesion protein-1: a potential PET imaging agent for diagnosing osteomyelitis

INTRODUCTION

Vascular adhesion protein-1 (VAP-1) is an infection/inflammation-inducible endothelial glycoprotein. Based on our previous studies, the most VAP-1-selective peptide (VAP-P1) was 1,4,7,10-tetraazacyclododecane-N',N'',N''',N-tetraacetic acid (DOTA)-conjugated, 68gallium (68Ga)-labeled (named [68Ga]DOTAVAP-P1) and evaluated preliminarily.

METHODS

Targeting was evaluated by using VAP-1-transfected cells. Biodistribution of [68Ga]DOTAVAP-P1 was studied by positron emission tomography imaging of healthy rats and rats with bone inflammation caused by Staphylococcus aureus infection. Uptake of [(68)Ga]DOTAVAP-P1 in osteomyelitis was compared with negative control peptide and competition with an excess of unlabeled DOTAVAP-P1.

RESULTS

[68Ga]DOTAVAP-P1 bound more efficiently to VAP-1-transfected cells than to controls. In rats, [68Ga]DOTAVAP-P1 cleared rapidly from blood circulation, excreted quickly in urine and showed an in vivo half-life of 26+/-2.3 min. Imaging of osteomyelitis demonstrated modest target-to-background ratio. Studies with the negative control peptide and competitors revealed a significantly lower uptake at the infection site compared to [68Ga]DOTAVAP-P1.

CONCLUSIONS

The results represent a proof-of-concept that infection-induced VAP-1 can be targeted by [68Ga]DOTA peptide. [68Ga]DOTAVAP-P1 is just the first candidate peptide and an essential opening for developing VAP-1-specific imaging agents.

Female patients with low systemic BMD are prone to bone loss in Gruen zone 7 after cementless total hip arthroplasty

BACKGROUND AND PURPOSE

Factors that lead to periprosthetic bone loss following total hip arthroplasty (THA) may not only depend on biomechanical implant-related factors, but also on various patient-related factors. We investigated the association between early changes in periprosthetic bone mineral density (BMD) and patient-related factors.

PATIENTS AND METHODS

39 female patients underwent cementless THA (ABG II) with ceramic-ceramic bearing surfaces. Periprosthetic BMD in the proximal femur was determined with DXA after surgery and at 3, 6, 12, and 24 months. 27 patient-related factors were analyzed for their value in prediction of periprosthetic bone loss.

RESULTS

Total periprosthetic BMD was temporarily reduced by 3.7% at 3 months (p < 0.001), by 3.8% at 6 months (p < 0.01), and by 2.6% at 12 months (p < 0.01), but recovered thereafter up to 24 months. Preoperative systemic osteopenia and osteoporosis, but not the local BMD of the operated hip, was predictive of bone loss in Gruen zone 7 (p = 0.04), which was the only region with a statistically significant decrease in BMD (23%, p < 0.001) at 24 months. Preoperative serum markers of bone turnover predicted the early temporary changes of periprosthetic BMD. The other patient-related factors failed to show any association with the periprosthetic BMD changes.

INTERPRETATION

Female patients with low systemic BMD show greater bone loss in Gruen zone 7 after cementless THA than patients with normal BMD. Systemic DXA screening for osteoporosis in postmenopausal patients before THA could be used to identify patients in need of prophylactic anti-resorptive therapy.

Frequency of multiple insemination in a natural population of Drosophila montana

The frequency of multiple insemination was studied in a boreal Drosophila montana population using mother-offspring data for a sex-linked allozyme locus. Mating with respect to the marker studied was random. In crowded laboratory cultures the heterozygous offspring had higher viability than homozygotes, but no deviations from Hardy-Weinberg proportions were found in natural populations. In multiply sired progenies the males did not contribute equally to the progeny, but the proportion sired by the second male was 0.76. The estimated frequency of multiple inseminated females was 1.19 +/- 0.31, indicating that practically all the females carried sperm of at least two males. The estimate is the largest ever reported in natural populations of Drosophila. However, the interspecific comparisons may not be relevant, because the frequency of multiple insemination does not necessarily reflect the real lifetime frequency of multiple matings. The effects of local ecology and life history characters, e.g., the uniform age structure and the temporal patterning of matings, on the high degree of detected multiple inseminations are discussed.

(68)Ga-DOTAVAP-P1 PET imaging capable of demonstrating the phase of inflammation in healing bones and the progress of infection in osteomyelitic bones

PURPOSE

Differentiation between bacterial infection and nonbacterial inflammation remains a diagnostic challenge. Vascular adhesion protein 1 (VAP-1) is a human endothelial protein whose cell surface expression is induced under inflammatory conditions, thus making it a highly promising target molecule for studying inflammatory processes in vivo. We hypothesized that positron emission tomography (PET) with gallium-68-labeled 1,4,7,10-tetraazacyclododecane-N',N'',N''',N''''-tetraacetic acid-peptide targeted to VAP-1 ((68)Ga-DOTAVAP-P1) could be feasible for imaging the early inflammatory and infectious processes in healing bones.

MATERIALS AND METHODS

Thirty-four Sprague-Dawley rats with diffuse Staphylococcus aureus tibial osteomyelitis and 34 rats with healing cortical bone defects (representing the inflammation stage of healing) were PET imaged using (68)Ga-DOTAVAP-P1 as a tracer. In addition, peripheral quantitative computed tomography and conventional radiography were performed. Bone samples for quantitative bacteriology and specimens were also processed for histomorphometry of inflammatory and infectious reactions.

RESULTS

PET imaging showed an uptake of (68)Ga-DOTAVAP-P1 in both the osteomyelitic bones and the healing cortical bone defects during the first 36 h after surgery. Thereafter, only the osteomyelitic tibias were delineated by PET. The osteomyelitic and control animals showed a similar uptake of the (68)Ga-DOTAVAP-P1 at 24 h, whereas a significant difference was observed at 7 days (p < 0.0001).

CONCLUSIONS

The current study showed that PET imaging with the new (68)Ga-DOTAVAP-P1 is capable of accurately demonstrating the phase of inflammation in healing bones and the progress of bacterial infection in osteomyelitic bones. Consequently, this novel imaging agent allowed for the differentiation of bone infection due to S. aureus and normal bone healing as soon as 7 days after onset.

In vitro and in vivo release of ciprofloxacin from osteoconductive bone defect filler

OBJECTIVES

Impregnation of antimicrobial agents within biodegradable carriers with osteoconductive properties could provide the means for one-stage surgical treatment of osteomyelitis. In this study, the in vitro and in vivo antibiotic release from this type of bone defect filler was characterized.

METHODS

Cylindrical pellets (2.5 x 1.5 mm) were manufactured from bioabsorbable poly(L-lactide-co-glycolide) (PLGA) matrix, ciprofloxacin [8.3 +/- 0.1% (w/w)] and osteoconductive bioactive glass microspheres (90-125 microm) [27 +/- 2% (w/w)]. In vitro studies were carried out to delineate the release profile of the antibiotic. The antimicrobial activity of the release antibiotic was verified with MIC testing. In a time-sequence study in the rabbit, pellets were surgically implanted in the proximal tibia and the antibiotic concentrations achieved in bone were measured at 1, 2, 3, 4, 5 and 6 months.

RESULTS

In vitro elution studies showed sustained release of ciprofloxacin at a therapeutic level (>2 microg/mL) over a time period of 4 months. The released ciprofloxacin had maintained its antimicrobial capacity against five standard ATCC strains. In vivo, the delivery system produced high local bone concentrations (247.9 +/- 91.0 mug/g of bone) for a time period of 3 months with no significant systemic exposure. Histomorphometry and micro-CT imaging confirmed new bone formation around the pellets within 3 months as a sign of an independent osteoconductive property of the composite.

CONCLUSIONS

The tested composite seems to be a promising option for local therapy of surgically treated bone infections. The main advantages are the antibiotic release for a definite time period with therapeutic concentrations, which may minimize slow residual release at suboptimal concentrations.

Comparison of 18F-FDG and 68Ga PET imaging in the assessment of experimental osteomyelitis due to Staphylococcus aureus

PURPOSE

Although positron emission tomography (PET) using 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG) is a promising imaging modality for bone infections, the technique may still give false-positive results due to unspecific uptake in healing bone. This experimental study compared 18F-FDG and 68Ga in PET imaging of osteomyelitis and normal bone healing.

METHODS

A diffuse osteomyelitis model of the tibia was applied in the rat (n=50). Two weeks after operation, PET imaging with 18F-FDG and 68Ga was performed, followed by peripheral quantitative computed tomography (pQCT) and radiography. Osteomyelitis was verified by quantitative bacteriology. In addition to in vivo imaging, ex vivo measurements of tissue radioactivity were performed to verify uptake of the tracers.

RESULTS

Compared with controls with normal bone healing, the osteomyelitic tibias showed increased SUV ratios (i.e. radioactivity ratios between the operated and non-operated sides) for both 18F-FDG (1.74+/-0.37) and 68Ga (1.62+/-0.28) (P<0.001). Ex vivo measurements also showed increased tracer accumulation in the infected bone (P=0.003 for 18F-FDG and P<0.001 for 68Ga). The intensity of 68Ga uptake reflected pathological changes of osteomyelitic bones measured by pQCT. The uptake of 18F-FDG, however, did not show as close a correlation with the anatomical changes. The healing bones without infection exhibited slightly elevated uptake of 18F-FDG (SUV ratio 1.16+/-0.06), but 68Ga did not accumulate in the healing bone, as judged on the basis of both in vivo imaging (SUV ratio 1.02+/-0.05) and ex vivo measurements (SUV 0.92+/-0.21) (P=0.003 and P=0.022 compared with 18F-FDG uptake, respectively).

CONCLUSION

This study suggests the feasibility of 68Ga PET imaging of bone infections. However, further studies are needed to clarify the value of 68Ga PET for clinical purposes.

The phylogenetic position of Drosophila eskoi deduced from P element and Adh sequence data

PCR screening with primers specific for the T-, M-, and O-type P element subfamilies was performed to investigate the interspecific distribution in 18 species and to reconstruct the phylogenetic history of the various types within the obscura species group. T-type elements occur in D. ambigua, D. tristis, D. obscura, D. subsilvestris, and D. eskoi. In the genomes of D. subobscura, D. madeirensis, and D. guanche they are present in the form of terminally truncated T-type derivatives. The wide distribution suggests that the T-type subfamily had a long evolutionary history in the obscura lineage. In contrast, the patchy occurrence of M- and O-type elements can be ascribed to four independent events of horizontal invasion of different lineages. The cladogenesis of the obscura group was investigated using a partial sequence of the Adh gene as a marker. In contrast to earlier findings, the position of D. eskoi had to be revised. D. eskoi appears as the closest relative of the D. ambigua clade, whereas D. tsukubaensis is the sister taxon of the species pair D. bifasciata/D. imaii. This result is in good accordance with the P element data, where high sequence similarity (95%) was found among the T-type elements of D. eskoi and those of D. ambigua and D. tristis.

Blue and yellow laccases of ligninolytic fungi

Extracellular laccases from submerged cultures of Coriolus versicolor BKM F-116, Panus tigrinus 8/18, Phlebia radiata 79 (ATCC 64658), Phlebia tremellosa 77-51 and from cultures of Pa. tigrinus 8/18, Ph. radiata 79 and Agaricus bisporus D-649 grown on wheat straw (solid-state fermentation) were purified. All enzymes from submerged cultures had a blue colour and characteristic absorption and EPR spectra. Laccases from the solid-state cultures were yellow-brown and had no typical blue oxidase spectra and also showed atypical EPR spectra. Comparison of N-terminal amino acid sequences of purified laccases showed high homology between blue and yellow-brown laccase forms. Formation of yellow laccases as a result of binding of lignin-derived molecules by enzyme protein is proposed.

Characterization of linne, a new autosomal eclosion rhythm mutant in Drosophila subobscura

A new putative gene, named linne, affecting circadian eclosion rhythm was found in a Norwegian strain of Drosophila subobscura. The phenotype of linne may be novel among Drosophila clock mutants. Eclosion is practically arrhythmic in light-dark cycles, but diel temperature cycles of 4 degrees C amplitude effectively entrain eclosion in continuous light and in continuous darkness. After that, the rhythm continues in constant temperature and darkness, but unlike other strains, it continues in constant temperature and light as well. Thus in the linne strain the coupling between light signals and pacemaker is disrupted, not the pacemaker itself. Genetic effects of linne were tested in crosses with a wild strain. Arrhythmicity was recessive and autosomal and showed monogenic inheritance, suggesting that arrhythmicity in linne is based on mutation on a single locus.

Genetic correlation between circadian eclosion rhythm and photoperiodic diapause in Drosophila littoralis

Populations of Drosophila littoralis are known to be latitudinally highly variable in photoperiodic adult diapause and pupal eclosion rhythm. Phenotypic correlations between the two time-measuring systems among the strains from different latitudes are, however, weak. In the present study, two differing strains were crossed reciprocally in order to search for causal (genetic) correlations between the two traits in the strains. Segregation in the F2 generations showed that variation in each trait was based on a few variable loci only. In the F2, flies having different eclosion times also differed in their diapause. This association was not complete and could have been due to genetic linkage between the traits. For that reason, the hybrid generations were raised for eight generations more to allow recombination between the traits. In F8, selection against diapause was started in the lines by raising them in a light-dark cycle of 15:9, where only females of the southern type reproduce. After eight selected generations, the lines were studied for the traits. Diapause was completely of the southern type, and the eclosion rhythm had also changed in parallel. The change in the phase of the free-running rhythm was not complete. From the present experiment, and from earlier knowledge of the geographical variation in D. littoralis, I conclude that the same pacemaker that is seen in the eclosion rhythm could also participate in daylength measurement for diapause. However, there are also noncorrelated variable parts in the measuring systems of both traits, which may mask the correlated variation.

Genetic polymorphism and evolution in parthenogenetic animals. V. Triploid Adoxus obscurus (Coleoptera: Chrysomelidae)

The genetic variability at 16 enzyme loci in 52 Scandinavian triploid parthenogenetic populations of the beetleAdoxus obscurushas been studied by starch-gel electrophoresis. The overall genotypes of different beetles have been compared with each other and with a sample from a diploid bisexual population from Canada. Eighty per cent of the parthenogenetic beetles have the same overall genotype. The remainder belong to six genotypes, three of which are found in only one population. The variability within and between parthenogenetic populations ofA. obscurusis much lower than in other comparable parthenogenetic insects studied by us. This is interpreted to be a consequence of the efficient migration of the genotypes with the highest fitness, leading to a replacement of less-adapted genotypes.A. obscurusis a flying insect, whereas the other parthenogenetic insects studied by us are sluggish flightless forms.

Genetic polymorphism and evolution in parthenogenetic animals. II. Diploid and polyploid Solenobia triquetrella (Lepidoptera: Psychidae)

Genic polymorphism at sixteen enzyme loci of four different chromosomal races of Solenobia triquetrella (bisexual, two diploid parthenogenetic races and tetraploid parthenogentiic) has been studied by starch gel electrophoresis. Isolated small diploid bisexual populations have rather uniform allele frequencies at all loci which we have studied. Diploid and tetraploid parthenogenetic individuals of this species are in general as heterozygous as bisexual ones. All parthenogenetic local populations are different from each other in the Alps. These parthenogenetic genotypes cannot be derived from a common ancestor through single mutations but rather bear evidence for a polyphyletic origin of parthenogenesis in Solenobia triquetrella. In the marginal distribution areas of the species in northern Europe single genotypes are spread over far larger areas than in the mountain regions of central Europe. This may be due to the old origin of parthenogenesis and polyploidy in northern Europe. No new parthenogenetic and polyploid strains have lately arisen in the regions outside of the Alps.