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Background: Bone marrow lesions (BMLs) in knee osteoarthritis (OA) have been assessed histopathologically and by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI); however, a direct comparison of the results has not been reported., Purpose: To evaluate and compare the findings by DCE-MRI and histopathology of subchondral BMLs in knee OA., Material and Methods: In total, 19 patients with medial tibiofemoral knee OA undergoing total knee arthroplasty were analyzed. Preoperative MRI, including a DCE sequence, was performed, and bone biopsies were obtained from the resected specimens corresponding to BML areas. The contrast enhancement by DCE-MRI was analyzed using semi-quantitative (area under the curve [AUC]), peak enhancement [PE]), and quantitative (Ktrans, Kep) methods. Enhancement in the medial OA compartment was compared with similar areas in a normal lateral compartment, and the DCE characteristics of BMLs were correlated with semi-quantitatively graded histopathological features., Results: AUC and PE were significantly higher in medial tibial and femoral BMLs compared with the values in the lateral condyles; Ktrans and Kep were only significantly higher in the tibial plateau. In the tibia, AUC and PE were significantly correlated with the grade of vascular proliferation, and PE also with the degree of marrow fibrosis. There was no significant correlation between AUC/PE and histopathological findings in the femur and no correlation between quantitative DCE parameters and histopathological findings., Conclusion: BML characteristics by semi-quantitative DCE in the form of AUC and PE may be used as parameters for the degree of histopathological vascularization in the bone marrow whereas quantitative DCE data were less conclusive., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: The tibial tuberosity-trochlear groove (TTTG) distance varies with the position of the knee in the MR or CT scanner. We present and assess a simple method for adjustment of adduction or abduction of the knee., Materials and Methods: MRI of the knee encompassing a three-dimensional (3D) sagittal sequence including ≥ 8 cm of the proximal tibia was analyzed (29 females, 17 males; median age 45 years). Using 3D visualization software, the central longitudinal axis of the proximal tibia (TA) was constructed, and the TTTG distance was measured before and after alignment of the TA. Observer reliability was assessed with inter- and intra-class correlation coefficient (ICC) and Bland-Altman plots., Results: Adduction of the knee occurred in 26 examinations, mean 2.7° (range 0.0° to 9.4°), and abduction in 20 examinations, mean 2.6° (range 0.0° to 7.2°). Following adjustment, the mean TTTG distance increased 2.4 mm (range 0.0 to 6.7 mm) in the knees positioned in adduction and decreased 2.3 mm when in abduction (range 0.0 to 5.5 mm). The correlation coefficient (r 2 ) between the deviation in adduction and abduction and the difference between TTTG unadjusted and adjusted was r 2  = 0.96. ICCs were excellent, but limits of agreement were close to ± 3 mm., Conclusion: Measurement of the TTTG distance by MRI is influenced by a systematic technique-dependent error caused by knee positioning in adduction or abduction. We suggest a simple method for adjusting the positioning.

Background: Distal radius fractures can adversely affect wrist function; for men with this fracture, the role played by fracture severity, age and osteoporosis on fracture outcome has not been sufficiently studied., Objective: To describe patient-reported outcome and the association with bone integrity, fracture severity and future fracture risk among young and older men with distal radius fracture., Methods: This prospective study includes 133 men with acute distal radius fracture, mean age 54 (range 21-88), who were followed for 12 months. They were categorized as younger (< 65) and older (65+). Main outcome was DASH (Disability of the Arm, Shoulder and Hand) at 12 months; DASH > 15 was defined as poor outcome. Fractures were classified and radiographic displacement identified at initial presentation and follow-up. BMD was measured and FRAX 10-year probability of fracture calculated., Results: Disability was higher in older men (DASH median 10 vs 2; p = 0.002); a clinically meaningful difference (ΔDASH = 10, p = 0.017) remained after adjustment for displacement, fracture classification and treatment method. Almost 50% of older men vs 14% in younger had poor outcome, p < 0.001. Bone mineral density did not independently predict outcome. Older men with a displaced fracture at initial presentation had greater disability (DASH median , IQR 45, 14;73) and risk of fracture (FRAX major osteoporotic 14, 8;21)., Conclusion: Men over the age of 65 with a distal radius fracture are more likely to have post-fracture disability regardless of radiographic appearance. Fracture displacement, indicating impaired bone strength, is also more common and associated with an increased risk of fracture within 10-years. Secondary fracture prevention should therefore be considered in men presenting with distal radius fracture.

Objective: To introduce and evaluate computed tomography (CT)-guided transarticular needle biopsy of the cartilaginous sacroiliac joint (SIJ) and to assess the biopsy results microscopically., Materials and Methods: The new CT-guided transarticular biopsy of the SIJ was performed in a young corpse and ten patients, two males and eight females aged 18-81 years. All patients had abnormal findings by magnetic resonance imaging (MRI) of the SIJs, including bone marrow edema, related to different types of joint disorders. The biopsies were focused on areas with bone marrow edema. The quality of the specimens obtained, using two different types of biopsy needles, was assessed microscopically., Results: Biopsies containing cartilage, subchondral plate, and bone marrow from the iliac and sacral sides were obtained from the corpse and three patients and from the iliac bone only in two patients. In three patients, the biopsy needles could not penetrate the bone marrow to the joint facet due to pronounced subchondral sclerosis, but adequate marrow biopsies were obtained. Two biopsies were inadequate, one due to technical problems and one was crushed during preparation. Histological assessment of eight adequate specimens revealed inflammatory bone marrow changes, except in two specimens from females with pronounced sclerosis conforming to osteitis condensans ilii., Conclusions: Transarticular SIJ biopsies are obtainable and can be directed towards areas with MRI abnormalities. They can be used to confirm inflammatory changes histologically. With the biopsy needles used, severe bone marrow sclerosis may hinder penetration to the cartilage, but bone marrow specimens can be obtained.

In this review about perfusion magnetic resonance imaging (pMRI), we consider it to give detailed insight into the distribution of the infarction in the femoral head in the early phase of Perthes disease. The degree of head involvement is closely related to the long-term prognosis, and as early surgical treatment of children with severe head involvement may be beneficial, pMRI is suggested as an examination in older children with early stages of Perthes disease. The use of gadolinium as contrast medium in otherwise healthy children seems safe, but long-term effects are unknown.

The concept of hip impingement and hip-preserving surgery has been appreciated in more detail since 2001 when a new surgical approach was reported and a hypothesis linking femoroacetabular impingement (FAI) with osteoarthritis was presented. Paralleling the introduction of hip arthroscopy, these events led to an increasing interest in the hip, and the number of publications has risen rapidly over the past 15 years, despite limited evidence levels and inconsistent methodology. Accordingly, etiology, diagnosis, prognosis, and the effects of treatment for FAI are still elusive due to a number of uncertainties and a lack of clear diagnostic criteria.Future research must focus on developing high-quality scientific studies, so thorough and reproducible methodology is needed. This review provides researchers, radiologists, and clinicians with a comprehensive approach to hip imaging with a focus on strategies to help guide the clinical diagnosis. Using evidence from current literature and knowledge from experienced clinicians, some of the imaging methodology challenges are deciphered., Competing Interests: None declared., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Objective:  To review the strengths, limitations, and new insights in the anatomy and magnetic resonance imaging (MRI) features of active and structural lesions of sacroiliitis in spondyloarthritis., Discussion:  MRI plays a key role in the diagnosis and follow-up of sacroiliitis in spondyloarthritis. MRI of the sacroiliac joints in affected patients may show active lesions such as bone marrow edema, capsulitis, enthesitis, or synovitis as well as structural changes such as erosion, fat infiltration, sclerosis, backfill, and ankylosis. Active lesions of sacroiliitis on MRI are particularly important for the diagnosis and assessment of ongoing active inflammation. Structural lesions increasingly gain importance for diagnosis and follow-up., Conclusion:  Active lesions remain the hallmark for assessment of inflammation in sacroiliitis. Structural lesions increasingly play a role in the diagnosis of spondyloarthritis., Competing Interests: Disclosure The authors report no conflicts of interest in this work., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Background: To evaluate whether clinical, radiographic or MRI findings are associated with long term risk for total knee arthroplasty (TKA) in persons with knee osteoarthritis., Methods: We performed a follow-up analysis of 100 persons with knee osteoarthritis who participated in a clinical trial between 2000 and 2002. Clinical data as well as radiography and MRI of the inclusion knee were obtained in all participants. Data on TKA procedures were extracted from The Danish National Patient Register. Clinical, radiographic and MRI findings were analyzed for associations with subsequent TKA., Results: During a mean follow-up period of 15 years, 66% received a TKA in the included knee (target knee); 37% also received a TKA in the other knee. The degree of joint space narrowing was highly associated with subsequent TKA (adjusted odds ratio (OR) 5.0 (95% confidence interval (95% CI) 2.6 - 9.9)) as was a radiological sum score comprising joint space narrowing, osteophytes, subchondral sclerosis and cysts (adjusted OR 1.7 (95% CI 1.3 - 2.1)). MRI detected bone marrow lesions, synovitis and effusion were similarly associated with subsequent TKA with an adjusted OR of 2.3 (95% CI 1.3 - 4.0), 2.8 (95% CI 1.5 - 5.2) and 1.9 (95% CI 1.2 - 3.1), respectively. Increased body mass index (BMI) was not associated with subsequent TKA in the target knee but was associated with TKA in the other knee (OR 2.3 (95% CI 1.2 - 4.3)., Conclusions: Radiographic findings including joint space narrowing and MRI detected bone marrow lesions, synovitis and effusion were all significantly associated with the long term risk of TKA in persons with knee osteoarthritis.

Background Diagnosis and treatment of patellofemoral disorders including osteoarthritis are currently often based on imaging and clinical assessment with patients in the supine position. Purpose To evaluate differences in patellar position in the trochlear groove and to assess the detection of medial and lateral patellofemoral (PF) osteoarthritis (OA) on axial radiographs in supine and standing positions, respectively. Material and Methods Thirty-five women and 23 men (mean age, 56 years; age range, 18-87 years) referred for routine radiographic examinations of the knees were included. Axial radiographs of the PF joint in both supine non-weight-bearing and standing weight-bearing position in 30° knee flexion were obtained of 111 knees. Measurements performed on the radiographs: patellar tilt, patellar displacement, joint space width, and grade of OA according to Ahlbäck. Results From supine to standing position the patella moved medially and medial joint space width and lateral patellar tilt angle decreased ( P < 0.0001 for the three measured parameters). In the standing position, medial PF OA was observed in 19 knees compared to three knees in the supine position. Fourteen knees had lateral PF OA with almost unchanged grade of OA irrespective of position. Conclusion In weight-bearing positions, the patella is positioned medially in the trochlear groove compared to supine non-weight-bearing positions. Therefore, this study suggests that the common occurrence of medial PF OA can generally not be detected on axial radiographs in supine non-weight-bearing positions and confirms the importance of imaging the PF joint in standing weight-bearing positions.

Background: Bone marrow lesions (BMLs) in knee osteoarthritis (OA) can be assessed using fluid sensitive and contrast enhanced sequences. The association between BMLs and symptoms has been investigated in several studies but only using fluid sensitive sequences. Our aims were to assess BMLs by contrast enhanced MRI sequences in comparison with a fluid sensitive STIR sequence using two different segmentation methods and to analyze the association between the MR findings and disability and pain., Methods: Twenty-two patients (mean age 61 years, range 41-79 years) with medial femoro-tibial knee OA obtained MRI and filled out a WOMAC questionnaire at baseline and follow-up (median interval of 334 days). STIR, dynamic contrast enhanced-MRI (DCE-MRI) and fat saturated T1 post-contrast (T1 CE FS) MRI sequences were obtained. All STIR and T1 CE FS sequences were assessed independently by two readers for STIR-BMLs and contrast enhancing areas of BMLs (CEA-BMLs) using manual segmentation and computer assisted segmentation, and the measurements were compared. DCE-MRIs were assessed for the relative distribution of voxels with an inflammatory enhancement pattern, N voxel , in the bone marrow. All findings were compared to WOMAC scores, including pain and overall symptoms, and changes from baseline to follow-up were analyzed., Results: The average volume of CEA-BML was smaller than the STIR-BML volume by manual segmentation. The opposite was found for computer assisted segmentation where the average CEA-BML volume was larger than the STIR-BML volume. The contradictory finding by computer assisted segmentation was partly caused by a number of outliers with an apparent generally increased signal intensity in the anterior parts of the femoral condyle and tibial plateau causing an overestimation of the CEA-BML volume. Both CEA-BML, STIR-BML and N voxel were significantly correlated with symptoms and to a similar degree. A significant reduction in total WOMAC score was seen at follow-up, but no significant changes were observed for either CEA-BML, STIR-BML or N voxel ., Conclusions: Neither the degree nor the volume of contrast enhancement in BMLs seems to add any clinical information compared to BMLs visualized by fluid sensitive sequences. Manual segmentation may be needed to obtain valid CEA-BML measurements.

Objective: The Assessment of SpondyloArthritis international Society (ASAS) has previously published criteria for spondyloarthritis (SpA). In the Spines of Southern Denmark cohort, which included patients with persistent low back pain and an unknown proportion of patients with SpA, our objectives were 1) to estimate the prevalence of magnetic resonance imaging (MRI) findings and clinical features included in the ASAS criteria for SpA and 2) to explore the associations between MRI findings and clinical features., Methods: We included patients ages 18-40 years with persistent low back pain who had been referred to the Spine Centre of Southern Denmark. We collected information on clinical features (including HLA-B27 and high-sensitivity C-reactive protein) and MRI findings in the spine and sacroiliac (SI) joints., Results: Of 1,020 included patients, 537 (53%) had at least 1 of the clinical features included in the ASAS criteria for SpA. Three clinical features were common-inflammatory back pain according to the ASAS criteria, a good response to nonsteroidal antiinflammatory drugs (NSAIDs), and family history of SpA. The prevalence of these features ranged from 15% to 17%. Sacroiliitis on MRI according to the ASAS definition was present in 217 patients (21%). Of those 217 patients, 91 (42%) had the minimum amount of bone marrow edema required according to the ASAS definition (a low bone marrow edema score). The presence of HLA-B27, peripheral arthritis, a good response to NSAIDs, and preceding infection were independently positively associated with MRI findings in the SI joints (odds ratios [ORs] of 1.9-9.0). The remaining 8 clinical features were not positively associated with MRI findings. Importantly, only age was independently associated with low bone marrow edema score at the SI joints (OR of 1.1 per year)., Conclusion: In this population, 53% had at least 1 clinical feature included in the ASAS criteria for SpA, and 21% had sacroiliitis according to the ASAS definition; furthermore, the associations between the clinical and imaging domains were inconsistent. The results indicate a need for further investigation of the importance of these findings in SpA, including investigation of the minimum requirements for defining sacroiliitis on MRI., (© 2016, American College of Rheumatology.)

Objective: To estimate the prevalence of degenerative and spondyloarthritis (SpA)-related magnetic resonance imaging (MRI) findings in the spine and sacroiliac joints (SIJs) and analyse their association with gender and age in persistent low back pain (LBP) patients., Methods: Degenerative and SpA-related MRI findings in the whole spine and SIJs were evaluated in Spine Centre patients aged 18-40 years with LBP., Results: Among the 1,037 patients, the prevalence of disc degeneration, disc contour changes and vertebral endplate signal (Modic) changes were 87 % (±SEM 1.1), 82 % (±1.2) and 48 % (±1.6). All degenerative spinal findings were most frequent in men and patients aged 30-40 years. Spinal SpA-related MRI findings were rare. In the SIJs, 28 % (±1.4) had at least one MRI finding, with bone marrow oedema being the most common (21 % (±1.3)). SIJ erosions were most prevalent in patients aged 18-29 years and bone marrow oedema in patients aged 30-40 years. SIJ sclerosis and fatty marrow deposition were most common in women. SIJ bone marrow oedema, sclerosis and erosions were most frequent in women indicating pregnancy-related LBP., Conclusion: The high prevalence of SIJ MRI findings associated with age, gender, and pregnancy-related LBP need further investigation of their clinical importance in LBP patients., Key Points: • The location of vertebral endplate signal changes supports a mechanical aetiology. • Several sacroiliac joint findings were associated with female gender and pregnancy-related back pain. • Sacroiliac joint bone marrow oedema was frequent and age-associated, indicating a possible degenerative aetiology. • More knowledge of the clinical importance of sacroiliac joint MRI findings is needed.

This article presents the recommendations of the European Society of Musculoskeletal Radiology Arthritis Subcommittee regarding the standards of the use of MRI in the diagnosis of musculoskeletal rheumatic diseases. The recommendations discuss (1) the role of MRI in current classification criteria of musculoskeletal rheumatic diseases (including early diagnosis of inflammation, disease follow-up, and identification of disease complications); (2) the impact of MRI on the diagnosis of axial and peripheral spondyloarthritis, rheumatoid arthritis, and juvenile spondyloarthritis; (3) MRI protocols for the axial and peripheral joints; (4) MRI interpretation and reporting for axial and peripheral joints; and finally, (5) methods for assessing MR images including quantitative, semiquantitative, and dynamic contrast-enhanced MRI studies., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Background: Longitudinal assessment of bone marrow lesions (BMLs) in knee osteoarthritis (KOA) by MRI is usually performed using semi-quantitative grading methods. Quantitative segmentation methods may be more sensitive to detect change over time. The purpose of this study was to evaluate and compare the validity and sensitivity to detect changes of two quantitative MR segmentation methods for measuring BMLs in KOA, one computer assisted (CAS) and one manual (MS) method., Methods: Twenty-two patients with KOA confined to the medial femoro-tibial compartment obtained MRI at baseline and follow-up (median 334 days in between). STIR, T1 and fat saturated T1 post-contrast sequences were obtained using a 1.5 T system. The 44 sagittal STIR sequences were assessed independently by two readers for quantification of BML. The signal intensities (SIs) of the normal bone marrow in the lateral femoral condyles and tibial plateaus were used as threshold values. The volume of bone marrow with SIs exceeding the threshold values (BML) was measured in the medial femoral condyle and tibial plateau and related to the total volume of the condyles/plateaus.The 95% limits of agreement at baseline were used to determine the sensitivity to change., Results: The mean threshold values of CAS and MS were almost identical but the absolute and relative BML volumes differed being 1319 mm3/10% and 1828 mm3/15% in the femur and 941 mm3/7% and 2097 mm3/18% in the tibia using CAS and MS, respectively. The BML volumes obtained by CAS and MS were significantly correlated but the tissue changes measured were different. The volume of voxels exceeding the threshold values was measured by CAS whereas MS included intervening voxels with normal SI.The 95% limits of agreement were narrower by CAS than by MS; a significant change of relative BML by CAS was outside the limits of -2.0%-4.7% whereas the limits by MS were -6.9%-8.2%. The BML changed significantly in 13 knees using CAS and in 10 knees by MS., Conclusion: CAS was a reliable method for measuring BML and more sensitive to detect changes over time than MS. The BML volumes measured by the two methods differed but were significantly correlated.

The anatomy of joints provides an important basis for understanding the nature and imaging of pathologic lesions and their imaging appearance. This applies especially to the sacroiliac (SI) joints, which play a major role in the diagnosis of spondyloarthritis. They are composed of two different joint portions, a cartilage-covered portion ventrally and a ligamentous portion dorsally, and thus rather complex anatomically. Knowledge of anatomy and the corresponding normal imaging findings are important in the imaging diagnosis of sacroiliitis, especially by MR imaging. A certain distinction between the two joint portions by MR imaging is only obtainable by axial slice orientation. Together with a perpendicular coronal slice orientation, it provides adequate anatomical information and thereby a possibility for detecting the anatomical site of disease-specific characteristics and normal variants simulating disease. This overview describes current knowledge about the normal macroscopic and microscopic anatomy of the SI joints., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Background: The Back Pain Cohort of Southern Denmark (BaPa Cohort) was initiated with the aim of evaluating the clinical relevance of magnetic resonance imaging (MRI) in the diagnosis of early spondyloarthritis (SpA). In order to facilitate the collection of MRI data for this study, an electronic evaluation form was developed including both SpA-related and degenerative axial changes. The objective of the current study was to assess the intra- and inter-observer agreement of the MRI changes assessed., Methods: Three radiologists evaluated 48 MRI scans of the whole spine and the sacroiliac joints from a subsample of the BaPa Cohort, consisting of patients with non-specific low back pain and patients with different stages of SpA features. The spine was evaluated for SpA-related and degenerative MRI changes and the SIJ for SpA-related changes. Inter- and intra-observer agreements were calculated with kappa statistics. In the interpretation of the kappa coefficient, the standards for strength of agreement reported by Landis and Koch were followed., Results: A total of 48 patients, 40% men and mean age of 31 years (range 18-40 years), were evaluated once by all three readers and re-evaluated by two of the readers after 4-12 weeks. For MRI changes in the spine, substantial to almost perfect observer agreement was found for the location and the size of vertebral signal changes and for disc degeneration and disc contour. For the sacroiliac joints, substantial or almost perfect observer agreement was found for the grading of bone marrow oedema and fatty marrow deposition, the depth of bone marrow oedema and for subchondral sclerosis. Global assessment of the SpA diagnosis had substantial to almost perfect observer agreements., Conclusion: The acceptable agreement for key MRI changes in the spine and sacroiliac joints makes it possible to use these MRI changes in the BaPa Cohort study and other studies investigating MRI changes in patients with non-specific low back pain and suspected SpA.

Spinal stenosis and degenerative spondylolisthesis share many symptoms and the same treatment, but their causes remain unclear. Bone mineral density has been suggested to play a role. The aim of this study was to investigate differences in spinal bone density between spinal stenosis and degenerative spondylolisthesis patients. 81 patients older than 60 years, who underwent DXA-scanning of their lumbar spine one year after a lumbar spinal fusion procedure, were included. Radiographs were assessed for disc height, vertebral wedging, and osteophytosis. Pain was assessed using the Low Back Pain Rating Scale pain index. T-score of the lumbar spine was significantly lower among degenerative spondylolisthesis patients compared with spinal stenosis patients (-1.52 versus -0.52, P = 0.04). Thirty-nine percent of degenerative spondylolisthesis patients were classified as osteoporotic and further 30% osteopenic compared to only 9% of spinal stenosis patients being osteoporotic and 30% osteopenic (P = 0.01). Pain levels tended to increase with poorer bone status (P = 0.06). Patients treated surgically for symptomatic degenerative spondylolisthesis have much lower bone mass than patients of similar age treated surgically for spinal stenosis. Low BMD might play a role in the development of the degenerative spondylolisthesis, further studies are needed to clarify this.

Objective. To determine the risk of intra- and periarticular cyst-like lesions of the knee joint in occupational kneeling. Methods. Magnetic resonance imaging of both knees (n = 282) was conducted in 92 male floor layers and 49 male graphic designers (referents), with a mean age of 55.6 years (range 42-70 years). The prevalence of cyst-like lesions was computed among floor layers and graphic designers, respectively, and associations with occupation summarized by odds ratio (OR) with 95% confidence intervals (CIs). Using logistic regression, models were adjusted for age, body mass index, knee injuries, and knee-straining sports. Results. Floor layers had a significantly higher prevalence of cyst-like lesions in the posterior part of the knee joint compared to graphic designers (OR 2.70, 95% CI 1.50-4.84). Floor layers also had a higher prevalence of fluid collections in the popliteus tendon recess (OR 2.17, 95% CI 0.99-4.77) and large cystic lesions of the popliteus muscle (OR 3.83, 95% CI 0.78-18.89). The prevalence of cystic lesions in the anterior part of the knee joint was low among floor layers (8.7%) and there was no significant difference between the two trade groups (P = 0.34). Conclusions. Occupational kneeling increases the risk of cyst-like lesions in the posterior part of the knee joint.

Older people are at increased risk of non-union after spinal fusion, but little is known about the factors determining the quality of the fusion mass in this patient group. The aim of this study was to investigate fusion mass bone quality after uninstrumented spinal fusion and to evaluate if it could be improved by additional direct current (DC) electrical stimulation. A multicenter RCT compared 40 and 100 μA DC stimulation with a control group of uninstrumented posterolateral fusion in patients older than 60 years. This report comprised 80 patients who underwent DEXA scanning at the 1 year follow-up. The study population consisted of 29 men with a mean age of 72 years (range 62-85) and 51 women with a mean age of 72 years (range 61-84). All patients underwent DEXA scanning of their fusion mass. Fusion rate was assessed at the 2 year follow-up using thin slice CT scanning. DC electrical stimulation did not improve fusion mass bone quality. Smokers had lower fusion mass BMD (0.447 g/cm(2)) compared to non-smokers (0.517 g/cm(2)) (P = 0.086). Women had lower fusion mass BMD (0.460 g/cm(2)) compared to men (0.552 g/cm(2)) (P = 0.057). Using linear regression, fusion mass bone quality, measured as BMD, was significantly influenced by gender, age of the patient, bone density of the remaining part of the lumbar spine, amount of bone graft applied and smoking. Fusion rates in this cohort was 34% in the control group and 33 and 43% in the 40 and 100 μA groups, respectively (not significant). Patients classified as fused after 2 years had significant higher fusion mass BMD at 1 year (0.592 vs. 0.466 g/cm(2), P = 0.0001). Fusion mass bone quality in older patients depends on several factors. Special attention should be given to women with manifest or borderline osteoporosis. Furthermore, bone graft materials with inductive potential might be considered for this patient population.

Study Design: Randomized controlled trial., Objective: To analyze long-term adjacent segment degeneration (ASD) after lumbar fusion on magnetic resonance imaging and compare randomization groups with and without anterior column support., Summary of Background Data: ASD can be a long-term complication after fusion. The prevalence and the cause of ASD are not well documented, but ASD are one of the main arguments for introducing the use of motion-preserving techniques as an alternative to fusion. Anterior lumbar interbody fusion combined with posterolateral lumbar fusion (ALIF+PLF) has been proved superior to posterolateral fusion alone regarding outcome and cost-effectiveness., Methods: Between 1996 and 1999, 148 patients with severe chronic low back pain were randomly selected for ALIF+PLF or for PLF alone. Ninety-five patients participated. ASD was examined on magnetic resonance imaging with regard to disc degeneration, disc herniation, stenosis, and endplate changes. Disc heights on radiographs taken at index surgery and at long-term follow-up were compared. Outcome was assessed by validated questionnaires., Results: The follow-up rate was 76%. ASD was similar between randomization groups. In the total cohort, endplate changes were seen in 26% of the participants and correlated significantly with the presence of disc degeneration and disc herniation. Disc degeneration and dorsal disc herniation were the parameters registered most frequently and were significantly more pronounced at the first adjacent level than at the second and the third adjacent levels. Patients without disc height reduction over time were significantly younger than patients with disc height reduction. Disc degeneration and stenosis correlated significantly with outcome at the first adjacent level., Conclusion: The cause of the superior outcome in the group with anterior support is still unclear. Compared with the findings reported in the literature, the prevalence of ASD is likely to be in concordance with the expected changes in a nonoperated symptomatic population and therefore not accelerated by fusion.

Objective: To examine the long-term efficacy and safety of five intra-articular injections with hyaluronan in knee osteoarthritis., Methods: A multicentre, randomised, placebo-controlled double-blind study of 337 patients fulfilling the American College of Rheumatology (ACR) criteria for knee osteoarthritis (clinical and laboratory) and with a Lequesne algofunctional index score (LFI) of 10 or greater. Patients received a hyaluronan product (sodium hyaluronate; Hyalgan) (n=167) or saline (n=170) intra-articularly weekly for 5 weeks and were followed up to 1 year. Time to recurrence was the primary efficacy parameter. LFI, pain on walking 50 m based on visual analogue scale (VAS pain 50 m), paracetamol consumption, patients' global assessment, Nottingham health profile, joint effusion and number of responders were secondary efficacy parameters. The efficacy parameters were analysed by intention to treat (ITT) and per protocol (PP). All adverse events (AE) were recorded as safety parameters., Results: Time to recurrence showed no significant treatment effect (ITT analysis, p=0.26). Change from baseline in LFI and VAS pain 50 m for the ITT population showed no treatment effect. Paracetamol consumption, patients' global assessment, responder rates and AE displayed no significant difference between treatment groups, analysed by both ITT and PP. Treatment compliance was 95% in the hyaluronan group and 99% in the placebo group. No safety problems were registered., Conclusion: In patients fulfilling the ACR criteria for osteoarthritis of the knee with moderate to severe disease activity (LFI > or = 10), five intra-articular injections of hyaluronan did not improve pain, function, paracetamol consumption or other efficacy parameters 3, 6, 9 and 12 months after the treatment.

Objective: We investigated the potential concordance of 2 different magnetic resonance (MR) sequences - short-tau inversion recovery (STIR) and fat-saturated T1-weighted spin-echo after application of gadolinium (Gd) contrast medium to detect active bone marrow abnormalities at the sacroiliac joints (SIJ) in patients with spondyloarthritis (SpA)., Methods: Blinded and using the Danish scoring method, we evaluated transaxial MR images of the 2 sequences in 40 patients with SpA with disease duration of 3-14 years. Both the cartilaginous and ligamentous portions of the SIJ were analyzed., Results: There was a significant positive correlation between the activity scores obtained by STIR and Gd-enhanced sequences (p < 0.0001). Agreement in the detection of bone marrow abnormalities occurred in 60 of the 80 joints, 35 with and 25 without signs of active disease. Discordance with STIR-positive marrow activity scores occurred in only 11 joints; Gd-enhanced positive scores in 9 joints. The STIR sequence detected remnants of marrow activity in the periphery of chronic fatty replacement not seen or partly obscured on the Gd sequence. Small subchondral enhancing lesions may not be scored on the STIR sequence, mostly because of reduced image resolution., Conclusion: Active bone marrow abnormalities were detected nearly equally well with STIR and Gd-enhanced fat-suppressed T1 sequences in patients with SpA, with STIR being most sensitive to visualize active abnormalities in the periphery of chronic changes.

Background: Biphasic calcium phosphate (BCP) ceramics has a potential advantage as an osteoconductive matrix and has an optimal resorption rate for bone formation. Using BCP ceramics as a bone graft during spinal fusion requires osteogenesis within the material and subsequent bridging between adjacent vertebrae to provide long-term support. Bisphosphonates have been reported to prolong the process of bone healing. The influence of bisphosphonate treatment on bone formation within BCP ceramics in spinal fusion remains unknown. The aim of this study was to evaluate the influence of alendronate on BCP osteogenesis in posterolateral spinal fusion., Methods: Posterolateral spinal fusion with pedicle screw fixation was performed at the lumbar spine in twenty-two pigs. BCP ceramics were applied as a bone graft to obtain bone fusion between adjacent transverse processes. Eleven pigs in the treatment group received oral alendronate 10 mg/d for three months postoperatively. Eleven pigs in the control group did not receive treatment with alendronate. All animals underwent posterolateral spinal fusion with BCP ceramics. The fusion rate was evaluated three months after the operation., Results: The fusion rates evaluated by X-ray were 27.3% in the treatment group and 20% in the control group. The fusion rates using histological evaluation were 18.2% in the treatment group and 20% in the control group. The mean volumes of fusion mass were (3.64 +/- 0.86) cm(3) in the treatment group and (4.26 +/- 0.63) cm(3) in the control group. No significant differences were found in either trabecular bone volume or residual BCP volume between treatment and control groups using histological evaluation. The new bone formation within BCP ceramics was greater in the area adjacent to transverse process (P < 0.01)., Conclusion: Oral alendronate with a dose of 10 mg daily do not inhibit bone formation within BCP ceramics or affect the fusion rate in posterolateral spinal fusion from porcine models.

Study Design: Randomized, controlled, multi-center trial., Objective: To investigate the effect of direct current (DC) electrical stimulation on fusion rates after lumbar spinal fusion in patients older than 60 years., Summary of Background Data: Older patients have increased complication rates after spinal fusion surgery. Treatments which have the possibility of enhancing functional outcome and fusion rates without lengthening the procedure could prove beneficial. DC-stimulation of spinal fusion has proven effective in increasing fusion rates in younger and "high risk" patients, but little information exist on the effect in older patients., Methods: A randomized clinical trial comprising 5 orthopedic centers. The study included a total of 107 patients randomized to uninstrumented posterolateral lumbar spinal fusion with or without DC-stimulation. Fusion rate was assessed at 2 year follow-up using thin slice CT. Functional outcome was assessed using Dallas Pain Questionnaire and Low Back Pain Rating Scale pain index. RESULTS.: Available follow-up after 2 years was 89% (84 of 95 patients). Fusion rates were surprisingly low. DC-stimulation had no effect on fusion rate: 35% versus 36% in controls. Other factors associated with low fusion rates were female gender (32% vs. 42% in males, P = 0.050) and smoking (21% vs. 42% in nonsmokers, P = 0.079). Patients who achieved a solid fusion as determined by CT had superior functional outcome and pain scores at their latest follow-up., Conclusion: Thin slice CT revealed very high nonunion rates after uninstrumented spinal fusion in older patients. DC-stimulation was not effective in increasing fusion rates in this patient population. The achievement of a solid fusion was associated with superior functional outcome.

Study Design: Randomized, controlled, multi-center trial., Objective: To investigate the effect of direct current (DC) electrical stimulation on functional and clinical outcome after lumbar spinal fusion in patients older than 60 years., Summary of Background Data: Older patients have increased complication rates after spinal fusion surgery. Treatments which have the possibility of enhancing functional outcome and fusion rates without lengthening the procedure could prove beneficial. DC-stimulation of spinal fusion has proven effective in increasing fusion rates in younger and "high risk" patients, but functional outcome measures have not been reported., Methods: A randomized, clinical trial comprising 5 orthopedic centers. The study included a total of 107 patients randomized to uninstrumented posterolateral lumbar spinal fusion with or without DC-stimulation. Functional outcome was assessed using Dallas Pain Questionnaire, SF-36, Low Back Pain Rating Scale pain index, and walking distance., Results: Follow-up after 1 year was 95/107 (89%). DC-stimulated patients had significant better outcome in 3 of 4 categories in the Dallas Pain Questionnaire, better SF-36 scores (not significantly), but no difference in pain scores were observed. Median walking distance at latest follow-up was better in the stimulated group (not significant). Walking distance was significantly associated with functional outcome. There was no difference in any of the functional outcome scores between patients who experienced a perioperative complication and those without complications., Conclusion: The achievement of a good functional outcome was heavily dependent on the obtained walking distance. DC-stimulated patients tended to have better functional outcome as compared to controls. No negative effects of perioperative complications could be observed on the short-term functional outcome.

Background: The objective of our study was to evaluate the association between occupational kneeling and compartment specific radiographic tibiofemoral (TF) and patellofemoral (PF) osteoarthritis (OA)., Methods: Questionnaire data and bilateral knee radiographs were obtained in 134 male floor layers and 120 male graphic designers (referents). Weight-bearing radiographs in three views (postero-anterior, lateral and axial) were classified according to joint space narrowing. After the exclusion of subjects with reports of earlier knee injuries the odds ratio (OR) with 95% confidence intervals (CI) of TF and PF OA was computed among floor layers compared to graphic designers in three age groups (/= 60 years). Using logistic regression, estimates were adjusted for body mass index and knee-straining sports. In addition, the association between trade seniority and TF OA was assessed in age-adjusted test for trend analyses., Results: The prevalence of TF OA was significantly higher among floor layers aged 50-59 years compared to graphic designers (OR = 3.6, 95% CI = 1.1-12.0) while non-significant estimates were found in the young and elderly age groups. Furthermore, the adjusted OR of TF OA increased with trade seniority among floor layers (test for trend, OR = 2.2, 95% CI = 1.0-5.1), but not among graphic designers (OR = 1.2, 95% CI = 0.4-3.5). There were no significant differences regarding PF OA between the two occupational groups., Conclusion: Results corroborate the existence of a causal relationship between occupational kneeling and radiographic TF OA and suggest a dose-response association with trade seniority. An association between kneeling and PF OA was however doubtful. Apparent discrepancies between findings in different age groups are most likely reflecting selection bias.

Objective: To evaluate the association between occupational kneeling and degenerative meniscal tears., Methods: Magnetic resonance imaging (MRI) of both knees was conducted in 92 male floor layers and 49 male graphic designers (referents), with a mean age of 55.6 years (range 42-70 yrs). The presence of grade 3 MRI signal intensities indicating degenerative tears of the anterior, middle, and posterior one-third of the lateral and medial menisci was assessed on 1.5-Tesla MRI scans. The odds ratio (OR) of meniscal tears was determined among floor layers compared to graphic designers. Using logistic regression, models were adjusted for age, body mass index, and knee-straining sports., Results: Degenerative tears were significantly more prevalent in the medial meniscus among floor layers than among graphic designers [OR 2.28, 95% confidence interval (CI) 1.10-4.98] and significantly more floor layers had medial tears in both knees (OR 3.46, 95% CI 1.41-8.48). Tears extending to the tibial aspect and localized in the middle and posterior one-third of the medial meniscus were most prevalent. Lateral meniscal tears were predominantly unilateral and the prevalence of lateral tears did not differ between the 2 study groups. Knee complaints occurred in about 50% of all floor layers, irrespective of the presence of meniscal tears., Conclusion: Occupational kneeling increases the risk of degenerative tears in the medial but not the lateral menisci in both knees.

Study Design: A porous tantalum implant (Hedrocel, Implex Corp., Allendale, NJ), designed to assist interbody lumbar fusion, was tested biologically in an experimental model. A total of 11 female Danish landrace pigs received 3 levels of anterior lumbar interbody fusion at L2-L3, L4-L5, and L6-L7. Each level was randomly assigned one of the procedures: (1) implantation of PT-ring with pedicle screw fixation (PSF), (2) implantation of a porous tantalum ring (PT-ring) stabilized anteriorly with staples, or (3) implantation of carbon fiber cage (CF-cage) stabilized anteriorly with 2 staples. Each implant was filled with autogenous iliac crest bone graft., Objectives: To evaluate the effects of PSF on the incorporation of autologous bone in a porous tantalum interbody device and to compare healing in PT-rings to that in CF-cages of autologous bone., Summary of Background Data: Despite the promising results that early clinical trials have shown, interbody fusion cage technology is still under debate because of uncertainties that include indications for surgery, criteria for fusion, material, cage design, cage subsidence, and the effect of immediate stabilization., Methods: Pigs were euthanized 6 months after surgery. Fusion segments were evaluated by plain radiography, conventional radiograph tomography, and histology., Results: Fusion segments with PSF had significantly fewer radiolucencies than the other 2 levels (P = 0.002). Improved interface healing and fusion rate were observed in PT-rings when supplemented with PSF (P = 0.03). His tomorphometric results showed that the percentage of bone and bone marrow space in the center of a PT-ring was not significantly different from that of its adjacent vertebral body, but PSF increased bone marrow and decreased fibrous tissue formation in a tantalum cage. However, a CF-cage had higher bone volume and lower bone marrow space inside the cage compared with its adjacent vertebral body (P < 0.001). Fibrous tissue formation inside and around a CF-cage was more than that of a PT-ring (P < 0.05)., Conclusion: Interbody fusion using a PT-ring cage packed with autologous bone achieved higher interface healing and more reliable fusion when fixated with supplementary pedicle screws than did fixated anteriorly with 2 staples. A lesser amount of bone graft was required, and bone remodeling was enhanced in the PT-ring when compared to the CF-cage.

Study Design: An experimental animal study with randomized, paired control design was conducted using a porcine model., Objectives: The aim of this study was to evaluate the influence of alendronate treatment and the significance of different amounts of bone graft on posterior lateral spine fusion., Summary of Background Data: Treatment with bisphosphonates inhibits osteoclast-induced bone resorption and increases bone quality and density. It has been widely used clinically for treatment of osteoporosis. Bisphosphonates have been reported to elongate the callus remodeling process during fracture healing. Bisphosphonate treatment may modify bone graft healing and the remodeling process in spine fusion. The bone resorption phase exists during the healing process. Extensive bone graft resorption could reduce the basis for new bone formation, which could be an important factor for failure of spine fusion. Furthermore, different amounts of initially applied bone graft may influence spine fusion rate and bone graft incorporation process., Methods: Twenty-two pigs were included in the study. Eleven pigs in the treatment group received alendronate 10 mg/day p.o. for 3 months after surgery. The other 11 pigs received no bisphosphonate and served as control group. Posterior lateral fusion with the CD Horizon system was performed on the lumbar spine using different amounts of autograft (4 g on one side and 8 g on the other side) in all animals. The fusion was evaluated using radiograph, CT scan, and histomorphometry at 3 months after operation., Results: There was no statistical difference in either fusion rate or fusion mass volume between the two groups. The fusion rate based on radiograph was 75% on the 8-g autograft side and 45% on the 4-g side (P < 0.05). The mean volume of fusion mass was 2.36 cm3 on the 4-g side and 3.29 cm3 on the 8-g side (P < 0.01). No difference was found in either trabecular bone volume or fusion rate between treatment and control groups using histologic evaluation.The treatment group showed a higher fibrous tissue volume(P < 0.05), higher proportion of woven bone structure(P < 0.001), and lower bone marrow volume (P = 0.088) in the fusion mass. Different amounts of bone graft did not change the tissue composition of the fusion mass., Conclusions: Alendronate treatment in this study decreased fusion mass remodeling without inhibiting fusion rate. Increased amounts of autologous bone graft could improve the fusion rate in this experimental spine fusion study.

This study investigated the healing potential of allograft from bisphosphonate-treated animals in anterior lumbar spine interbody fusion. Three levels of anterior lumbar interbody fusion with Brantigan cages were performed in two groups of five landrace pigs. Empty Brantigan cages or cages filled with either autograft or allograft were located randomly at different levels. The allograft materials for the treatment group were taken from the pigs that had been fed with alendronate, 10 mg daily for 3 months. The histological fusion rate was 2/5 in alendronate-treated allograft and 3/5 in non-treated allograft. The mean bone volume was 39% and 37.2% in alendronate-treated or non-treated allograft (NS), respectively. No statistical difference was found between the same grafted cage comparing two groups. The histological fusion rate was 7/10 in all autograft cage levels and 5/10 in combined allograft cage levels. No fusion was found at all in empty cage levels. With the numbers available, no statistically significant difference was found in histological fusion between autograft and allograft applications. There was a significant difference of mean bone volume between autograft (49.2%) and empty cage (27.5%) (P<0.01). In conclusion, this study did not demonstrate different healing properties of alendronate-treated and non-treated allograft for anterior lumbar interbody fusion in pigs.

Objective: To determine whether work performed with the arms in a highly elevated position is associated with alterations in the rotator cuff tendons as assessed by magnetic resonance imaging (MRI)., Methods: A cross-sectional study was performed in a historical cohort of male machinists, car mechanics, and house painters. The participants were right-handed, ages 40-50 years, and had been employed in their trades for not less than 10 years. Seventy-one percent of invited subjects participated (136 of 192). Lifetime upper arm elevation was assessed by direct measurements combined with individual work histories obtained by questionnaire and from registry data. Supraspinatus tendinopathy was evidenced by MRI signal intensity changes and morphologic alterations. Infraspinatus and subscapularis tendinopathy were also assessed. Additional outcomes were acromioclavicular joint degeneration and humeral head cysts. The MRI findings were evaluated by radiologists who were blinded to exposure status and symptoms., Results: An exposure-response relationship was found between lifetime upper arm elevation and supraspinatus tendinopathy, with an age-adjusted odds ratio of 1.27 (95% confidence interval 1.02-1.60) for a 5-month increase in the total number of full-time working months spent with the arm elevated >90 degrees ., Conclusion: Work with the arms in a highly elevated position is associated with MRI-diagnosed alterations in the supraspinatus tendon. By demonstrating the first part of a possible biologic pathway, the study corroborates the work-relatedness of rotator cuff disorders., (Copyright 2004 American College of Rheumatology)

Background Impaction grafting can be achieved inside the spinal fusion cages, but its effect on bone graft incorporation and spinal fusion has not been studied. Animals and methods We investigated the effect of impaction grafting on the bone graft healing and fusion potential of beta-tricalcium phosphate (beta-TCP) inside the carbon fiber reinforced spinal fusion device (Brantigan cage) in 10 Danish landrace pigs. Lumbar spine interbody fusion of L2/3, L4/5 and L6/7 using carbon fiber cages was performed on each pig. Cages filled with either loosely-packed autologous iliac bone graft, rod-impacted autologous bone graft or beta-TCP were randomly distributed to the three fusion levels. Half of the animals were followed for 8 weeks, and the other half for 16 weeks. Results Radiographs and CT evaluations showed that autograft levels had significantly better results than beta-TCP levels (p<0.001 Fisher's Exact Test). However, the difference between impacted and loosely-packed levels was not significant. Histomorphometric analysis showed no difference between the loosely-packed and impacted cages with regard to bone volume, bone marrow volume, cartilage and fibrous tissue volume, while both of the autograft levels differed from the beta-TCP levels in all of the aforementioned parameters. Fluorochrome studies demonstrated that bone mineral apposition rate was significantly higher in the impacted cages than in the loosely-packed cages at 16 weeks. Interpretation Manual impaction of autologous bone graft into the carbon fiber cages resulted in a faster mineral apposition rate by 16 weeks. Bone ingrowth and spinal fusion were not influenced by impaction grafting., (Copyright 2004 Taylor & Francis)

Platelet-rich plasma (PRP) is an autogenous source of growth factor and has been shown to enhance bone healing both in clinical and experimental studies. PRP in combination with porous hydroxyapatite has been shown to increase the bone ingrowth in a bone chamber rat model. The present study investigated whether the combination of beta tricalcium phosphate (beta-TCP) and PRP may enhance spinal fusion in a controlled animal study. Ten Danish Landrace pigs were used as a spinal fusion model. Immediately prior to the surgery, 55 ml blood was collected from each pig for processing PRP. Three-level anterior lumbar interbody fusion was performed with carbon fiber cages and staples on each pig. Autogenous bone graft, beta-TCP, and beta-TCP loaded with PRP were randomly assigned to each level. Pigs were killed at the end of the third month. Fusion was evaluated by radiographs, CT scanning, and histomorphometric analysis. All ten pigs survived the surgery. Platelet concentration increased 4.4-fold after processing. Radiograph examination showed 70% (7/10) fusion rate in the autograft level. All the levels with beta-TCP+PRP showed partial fusion, while beta-TCP alone levels had six partial fusions and four non-fusions ( P=0.08). CT evaluation of fusion rate demonstrated fusion in 50% (5/10) of the autograft levels. Only partial fusion was seen at beta-TCP levels and beta-TCP+PRP levels. Histomorphometric evaluation found no difference between beta-TCP and beta-TCP+PRP levels on new bone volume, remaining beta-TCP particles, and bone marrow and fibrous tissue volume, while the same parameters differ significantly when compared with autogenous bone graft levels. We concluded from our results in pigs that the PRP of the concentration we used did not improve the bone-forming capacity of beta-TCP biomaterial in anterior spine fusion. Both beta-TCP and beta-TCP+PRP had poorer radiological and histological outcomes than that of autograft after 3 months.

The purpose of this study was to investigate the treatment response in lateral epicondylitis (tennis elbow) by MRI. Magnetic resonance imaging was obtained in 30 patients with clinical symptoms of lateral epicondylitis of the elbow using T1-, T2- and T2-weighted fat-saturated (FS) sequences. The patients were randomised to either i.m. corticosteroid injection ( n=16) or immobilisation in a wrist splint ( n=14). Magnetic resonance imaging of the elbow was performed on a 1.5-T MR system at baseline and after 6 weeks. The extensor carpi radialis (ECRB) tendon, the radial collateral ligament, lateral humerus epicondyle at tendon insertion site, joint fluid and signal intensity changes within brachio-radialis and anconeus muscles were evaluated on the MR unit's workstation before and after 6 weeks of treatment. The MRI was performed once in 22 healthy controls for comparison and all images evaluated by an investigator blinded to the clinical status of the subjects. The MR images showed thickening with separation of the ECRB tendon from the radial collateral ligament and abnormal signal change in 25 of the 30 patients on the T1-weighted sequences at inclusion. The signal intensity of the ECRB tendon was increased in 24 of the 30 patients with lateral epicondylitis of the elbow on the T2-weighted FS sequences. In the patients there were no associations between pathologically signal intensity within the ECRB tendon on T1- and T2-weighted sequences and the degree of self-reported pain (Dumbells test) at inclusion. In general, the MRI changes persisted in the patients at follow-up after 6 weeks despite clinical remission. The increased signal intensity within the extensor tendon is indicative of lateral epicondylitis humeri. The changes in signal intensity and morphology of ECRB tendon seem to be chronic and may persist despite clinical improvement.

"Spinal instrumentation without fusion" techniques, which do not interfere with spinal growth, have been used extensively in the treatment of progressive spinal scoliosis in very young children. Due to subperiosteal exposure, the process of spinal instrumentation may induce spontaneous bony fusion. Instrumentation and surgical techniques have been modified in order to prevent spontaneous posterior fusion from occurring in children. An absorbable ADCON-L gel has been shown to inhibit scar and epidural adhesions following spinal surgeries. However, little is known about its influence on spinal fusion. In the present study, a single-level intertransverse arthrodesis at L4-5 on both sides was performed on each of nine pigs. Each side was randomly designed to receive autogenous bone graft with or without ADCON-L gel. The animals were followed for 10 weeks postoperatively. A fusion rate of 78% (7/9) was obtained in the autograft treatment by plain X-ray and CT evaluation, while the autograft/ADCON-L treatment yielded a 0% (0/9) fusion rate ( p = 0.001). Histomorphometric evaluation revealed that the addition of ADCON-L gel to bone graft decreased bone and bone marrow formation and significantly increased fibrous tissue formation. No statistical difference between the two treatments was found in cartilage, bone surface density, osteoid surfaces or osteoclast-covered surfaces in any zone. We conclude that ADCON-L gel mixed into autogenous bone graft can delay or decrease bone formation at spinal arthrodesis sites, thus influencing the extent of spinal fusion. This accords with our hypothesis that the use of ADCON-L gel can prevent not only the occurrence of spontaneous fusion in very young scoliosis patients after instrumentation without fusion, but also re-ossification of a decompressed spinal canal.

Background Context: In preclinical and clinical joint replacement applications, porous tantalum has been shown to be osteoconductive and effective for biological fixation. Relatively little research has been undertaken to investigate the porous tantalum implants for potential application in intervertebral spinal fusion., Purpose: The current study was designed to assess the radiographic and histological performance of porous tantalum and carbon fiber devices in the porcine anterior lumbar interbody fusion (ALIF) model., Study Design: A total of 10 Danish Landrace pigs underwent a three-level anterior intervertebral lumbar arthrodeses at L2-L3, L4-L5 and L6-L7. Each level was randomly allocated to one of three implants: a solid piece of porous tantalum, a porous tantalum ring packed with autograft or a carbon fiber cage, likewise packed with autograft. Two staples for fixation were supplemented in front of implant., Methods: Pigs were sacrificed 3 months after operation. Specimens were evaluated by plain radiography, conventional tomography and histology., Results: Bone graft filled into the central hole of the porous tantalum ring was less than that of the carbon fiber cage (p<.001). Radiolucencies around the porous tantalum solid were significantly higher than the carbon fiber cage (p=.02) and were not different between the porous tantalum ring and the carbon fiber cage. The bone volume in the hole of implants, within the pores of the porous tantalum and in the implant interface did not differ between implants. Bone volume in the hole of the porous tantalum ring did not differ from that of the adjacent vertebral bone; however, it was significantly different in the carbon fiber cage and the adjacent vertebral bone (p=.005)., Conclusions: In this porcine ALIF model, the radiographic and histological appearances of the porous tantalum ring were equivalent to those of the carbon fiber cage. The high presence of radiolucencies and fibrous tissue layer at the vertebrae-implant interface suggests that an initial stabilizing biomechanical environment is important in order to achieve bone ingrowth in the interbody fusion devices in this ALIF model.

Objective: To present results of optimising scoliosis examination by changing from a conventional film/grid (F/G) to air-gap technique using computed radiography (CR), and to evaluate different methods for estimating effective radiation doses., Materials and Methods: Forty-nine children and adolescents were examined with an F/G technique, and 21 with air-gap and CR techniques. Entrance surface doses (ESD) were determined with lithium fluoride thermoluminescence dosimeters. For all patients, the effective radiation doses were determined using a hermaphrodite PCXMC computer program. For all F/G radiographs, the effective doses were also determined according to the NRPB-R279 report, and for 22 children (>9 years and/or >40 kg) also with the ODS-60 program, which allows separate gender calculations. Accumulated doses for 37 children examined more than once with F/G examinations were assessed., Results: For F/G techniques, the ESDs for both frontal and lateral views varied with age and were significantly correlated to the patients' thickness. The calculated effective doses using the PCXMC program and the NRPB-R279 did not differ significantly for all frontal and lateral radiographs, respectively, but ODS-60 gave significantly higher values in female subjects. With air-gap and CR techniques, the mean effective doses were reduced by a factor over 10. The mean accumulated effective dose for 37 children with a mean of seven F/G examinations was 6.1 mSv, implying a risk of death of about 1:2,000 for boys and at least 1:1,000 for girls., Conclusions: Paediatric scoliosis radiography should be considered a specialised procedure, which has to be optimised using a non-grid technique.

Intervertebral disc has been shown to be related to low back pain and nerve root injury in pathologic conditions. However, little is known about its influence on spinal fusion. With the development of minimal invasive operations, such as laparoscopic anterior spinal fusion with cages, insufficient discectomy may occur. With its inflammatory properties, the residue nucleus pulposus may have an effect on spinal fusion. In this study, a two-level lumbar spine interbody fusion (L3/4, L5/6) with a Brantigan cage was performed on ten Danish Landrace pigs. Each level was randomly assigned to one of the following methods: (1) implantation of Brantigan cage filled with autogenous iliac crest bone graft, or (2) implantation of Brantigan cage filled with a mixture of autograft and the nucleus pulposus tissue harvested from the disc level in which it was to be inserted. Each level was stabilized with two staples. The pigs were followed for 12 weeks in the same standardized condition. After sacrifice, the lumbar spines were taken out, and plain X-ray, computed tomographic (CT) scanning and histomorphometry were performed to study the fusion mass inside the cages. From plain radiographs, new bone formation could be seen inside and around the cage. CT evaluation showed that the nucleus pulposus level had a 20% (2/10) fusion rate, while the pure autograft level had a 70% (7/10) fusion rate ( P=0.07). The histological fusion rate was even lower in the nucleus pulposus level (10%), and was significantly different from the autograft level (70%, P=0.02). Histomorphometric parameters of new bone formation, bone marrow space and fibrous tissue differed significantly between the two levels ( P=0.04; P=0.02; P=0.04 respectively). We conclude that when nucleus pulposus is mixed with the autogenous bone graft, it can delay or decrease the bone formation inside the cage, thus influencing the final fusion.