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Year of Publication
1.  Three-dimensional mechanical evaluation of joint contact pressure in 12 periacetabular osteotomy patients with 10-year follow-up 
Acta Orthopaedica  2009;80(2):155-161.
Background and purpose Because of the varying structure of dysplastic hips, the optimal realignment of the joint during periacetabular osteotomy (PAO) may differ between patients. Three-dimensional (3D) mechanical and radiological analysis possibly accounts better for patient-specific morphology, and may improve and automate optimal joint realignment.
Patients and methods We evaluated the 10-year outcomes of 12 patients following PAO. We compared 3D mechanical analysis results to both radiological and clinical measurements. A 3D discrete-element analysis algorithm was used to calculate the pre- and postoperative contact pressure profile within the hip. Radiological angles describing the coverage of the joint were measured using a computerized approach at actual and theoretical orientations of the acetabular cup. Quantitative results were compared using postoperative clinical evaluation scores (Harris score), and patient-completed outcome surveys (q-score) done at 2 and 10 years.
Results The 3D mechanical analysis indicated that peak joint contact pressure was reduced by an average factor of 1.7 subsequent to PAO. Lateral coverage of the femoral head increased in all patients; however, it did not proportionally reduce the maximum contact pressure and, in 1 case, the pressure increased. This patient had the lowest 10-year q-score (70 out of 100) of the cohort. Another hip was converted to hip arthroplasty after 3 years because of increasing osteoarthritis.
Interpretation The 3D analysis showed that a reduction in contact pressure was theoretically possible for all patients in this cohort, but this could not be achieved in every case during surgery. While intraoperative factors may affect the actual surgical outcome, the results show that 3D contact pressure analysis is consistent with traditional PAO planning techniques (more so than 2D analysis) and may be a valuable addition to preoperative planning and intraoperative assessment of joint realignment.
doi:10.3109/17453670902947390
PMCID: PMC2689368  PMID: 19404795
2.  Countrywise results of total hip replacement 
Acta Orthopaedica  2014;85(2):107-116.
Background and purpose
An earlier Nordic Arthroplasty Register Association (NARA) report on 280,201 total hip replacements (THRs) based on data from 1995–2006, from Sweden, Norway, and Denmark, was published in 2009. The present study assessed THR survival according to country, based on the NARA database with the Finnish data included.
Material and methods
438,733 THRs performed during the period 1995–2011 in Sweden, Denmark, Norway, and Finland were included. Kaplan-Meier survival analysis was used to calculate survival probabilities with 95% confidence interval (CI). Cox multiple regression, with adjustment for age, sex, and diagnosis, was used to analyze implant survival with revision for any reason as endpoint.
Results
The 15-year survival, with any revision as an endpoint, for all THRs was 86% (CI: 85.7–86.9) in Denmark, 88% (CI: 87.6–88.3) in Sweden, 87% (CI: 86.4–87.4) in Norway, and 84% (CI: 82.9–84.1) in Finland. Revision risk for all THRs was less in Sweden than in the 3 other countries during the first 5 years. However, revision risk for uncemented THR was less in Denmark than in Sweden during the sixth (HR = 0.53, CI: 0.34–0.82), seventh (HR = 0.60, CI: 0.37–0.97), and ninth (HR = 0.59, CI: 0.36–0.98) year of follow-up.
Interpretation
The differences in THR survival rates were considerable, with inferior results in Finland. Brand-level comparison of THRs in Nordic countries will be required.
doi:10.3109/17453674.2014.893498
PMCID: PMC3967250  PMID: 24650019
3.  Patient-reported outcome and risk of revision after shoulder replacement for osteoarthritis 
Acta Orthopaedica  2014;85(2):117-122.
Purpose
We used patient-reported outcome and risk of revision to compare hemiarthroplasty (HA) with total shoulder arthroplasty (TSA) and stemmed hemiarthroplasty (SHA) with resurfacing hemiarthroplasty (RHA) in patients with glenohumeral osteoarthritis.
Patients and methods
We included all patients reported to the Danish Shoulder Arthroplasty Registry (DSR) between January 2006 and December 2010. 1,209 arthroplasties in 1,109 patients were eligible. Western Ontario Osteoarthritis of the Shoulder index (WOOS) was used to evaluate patient-reported outcome 1 year postoperatively. For simplicity of presentation, the raw scores were converted to a percentage of the maximum score. Revision rates were calculated by checking reported revisions to the DSR until December 2011. WOOS and risk of revision were adjusted for age, sex, previous surgery, and type of osteoarthritis.
Results
There were 113 TSAs and 1096 HAs (837 RHAs and 259 SHAs). Patients treated with TSA generally had a better WOOS, exceeding the predefined minimal clinically important difference, at 1 year (mean difference 10, p < 0.001). RHA had a better WOOS than SHA (mean difference 5, p = 0.02), but the difference did not exceed the minimal clinically important difference. There were no statistically significant differences in revision rate or in adjusted risk of revision between any of the groups.
Interpretation
Our results are in accordance with the results from other national shoulder registries and the results published in systematic reviews favoring TSA in the treatment of glenohumeral osteoarthritis. Nonetheless, this registry study had certain limitations and the results should be interpreted carefully.
doi:10.3109/17453674.2014.893497
PMCID: PMC3967251  PMID: 24650020
4.  The effect of femoral offset modification on gait after total hip arthroplasty 
Acta Orthopaedica  2014;85(2):123-127.
Background and purpose
A decrease of 15% in femoral offset (FO) has been reported to generate a weakness of the abductor muscle, but this has not been directly linked to an alteration of gait. Our hypothesis was that this 15% decrease in FO may also generate a clinically detectable alteration in the gait.
Patients and methods
We performed a prospective comparative study on 28 patients who underwent total hip arthroplasty (THA) for unilateral primary osteoarthritis. The 3D hip anatomy was analyzed preoperatively and postoperatively. 3 groups were defined according to the alteration in FO following surgery: a minimum decrease of 15% (9 patients), restored (14), and a minimum increase of 15% (5). A gait analysis was performed at 1-year follow-up using an ambulatory device. Each limb was compared to the contralateral healthy limb.
Results
In contrast to the “restored” group and the “increased” group, in the “decreased” group there was a statistically significant asymmetry between sides, with reduced range of motion and a lower maximal swing speed on the operated side.
Interpretation
A decrease in FO of 15% or more after THA leads to an alteration in the gait. We recommend 3-D preoperative planning because the FO may be underestimated by up to 20% on radiographs and it may therefore not be restored, with clinical consequences.
doi:10.3109/17453674.2014.889980
PMCID: PMC3967252  PMID: 24564749
5.  A simple visual analog scale for pain is as responsive as the WOMAC, the SF-36, and the EQ-5D in measuring outcomes of revision hip arthroplasty 
Acta Orthopaedica  2014;85(2):128-132.
Background and purpose
Little is known about the comparative performance of patient-reported outcome measures in revision hip arthroplasty. We compared the performance of the WOMAC, the SF-36, the EQ-5D, and a pain-related visual analog scale (VAS) in revision hip arthroplasty.
Methods
45 patients with aseptic prosthetic loosening following primary hip arthroplasty completed the WOMAC, the SF-36, the EQ-5D, and a VAS for pain—at baseline and 2 years after revision. Responsiveness of the measures was compared with the effect size (with ≥ 0.8 being considered large). Agreement between scales measuring the same type of outcome (pain or physical function) was assessed with the Bland-Altman method.
Results
The mean preoperative scores for the pain and physical function scales of WOMAC and SF-36, EQ-5D index, and VAS for pain improved statistically significantly 2 years after revision. The effect size for the WOMAC pain was 1.7, that for SF-36 pain was 1.4, that for WOMAC physical function was 1.6, that for SF-36 physical function was 0.8, and that for EQ-5D index was 1.2. The VAS for pain had an effect size of 2.1, which was larger than that for SF-36 pain and for the EQ-5D index (p ≤ 0.03) but not for WOMAC pain (p = 0.2). The limits of agreement between WOMAC pain, SF-36 pain, and the VAS scale measuring pain—and between the WOMAC and SF-36 scales measuring physical function—were wide. Internal-consistency reliability was high for the WOMAC and SF-36 scales but low for the EQ-5D.
Interpretation
In patients with first-time revision hip arthroplasty done for aseptic loosening, the WOMAC, SF-36, and EQ-5D showed high responsiveness in measuring patient-reported outcomes and the simple VAS for pain performed equally well.
doi:10.3109/17453674.2014.887951
PMCID: PMC3967253  PMID: 24479622
6.  Retrieval analysis of alumina ceramic-on-ceramic bearing couples 
Acta Orthopaedica  2014;85(2):133-140.
Background and purpose
Ceramic-on-ceramic (CoC) bearings have been in use in total hip replacement (THR) for more than 40 years, with excellent long-term survivorship. Although there have been several simulator studies describing the performance of these joints, there have only been a few retrieval analyses. The aim of this study was to investigate the wear patterns, the surface properties, and friction and lubrication regimes of explanted first-generation alumina bearings.
Materials and methods
We studied 9 explanted CoC bearings from Autophor THRs that were revised for aseptic loosening after a mean of 16 (range 7–19) years. The 3D surface roughness profiles of the femoral heads and acetabular cups (Srms, Sa, and Ssk) were measured to determine the microscopic wear. The bearings were imaged using an atomic-force microscope in contact mode, to produce a topographical map of the surfaces of the femoral heads. Friction tests were performed on the bearing couples to determine the lubrication regime under which they were operating during the walking cycle. The diametral clearances were also measured.
Results
3 femoral heads showed stripe wear and the remaining 6 bearings showed minimal wear. The femoral heads with stripe wear had significantly higher surface roughness than the minimally worn bearings (0.645 vs. 0.289, p = 0.04). High diametral clearances, higher than expected friction, and mixed/boundary lubrication regimes prevailed in these retrieved bearings.
Interpretation
Despite the less than ideal tribological factors, these first-generation CoC bearings still showed minimal wear in the long term compared to previous retrieval analyses.
doi:10.3109/17453674.2014.894390
PMCID: PMC3967254  PMID: 24650021
7.  Local anesthetic wound infiltration for pain management after periacetabular osteotomy 
Acta Orthopaedica  2014;85(2):141-146.
Background and purpose
To our knowledge, there is no evidence to support the use of local infiltration analgesia (LIA) for postoperative pain relief after periacetabular osteotomy (PAO). We investigated the effect of wound infiltration with a long-acting local anesthetic (ropivacaine) for postoperative analgesia after PAO.
Patients and methods
We performed a randomized, double-blind, placebo-controlled trial (ClinicalTrials.gov: NCT00815503) in 53 patients undergoing PAO to evaluate the effect of local anesthetic infiltration on postoperative pain and on postoperative opioid consumption. All subjects received intraoperative infiltration followed by 5 postoperative injections in 10-hour intervals through a multi-holed catheter placed at the surgical site. 26 patients received ropivacaine and 27 received saline. The intervention period was 2 days and the observational period was 4 days. All subjects received patient-controlled opioid analgesia without any restrictions on the total daily dose. Pain was assessed at specific postoperative time points and the daily opioid usage was registered.
Results
Infiltration with 75 mL (150 mg) of ropivacaine did not reduce postoperative pain or opioid requirements during the first 4 days.
Interpretation
The clinical importance of ropivacaine as single component in postoperative treatment of pain is questionable, and we are planning further studies to explore the potential of LIA in larger volume—and also a multimodal regimen—to treat pain in this category of patients.
doi:10.3109/17453674.2014.899840
PMCID: PMC3967255  PMID: 24650022
8.  Where is the neck? 
Acta Orthopaedica  2014;85(2):147-151.
Background and purpose
The alpha angle is the most used measurement to classify concavity of the femoral head-neck junction. It is not only used for treatment decisions for hip impingement, but also in cohort studies relating hip morphology and osteoarthritis. Alpha angle measurement requires identification of the femoral neck axis, the definition of which may vary between studies. The original “3-point method” uses 1 single point to construct the femoral neck axis, whereas the “anatomic method” uses multiple points and attempts to define the true anatomic neck axis. Depending on the method used, the alpha angle may or may not account for other morphological characteristics such as head-neck offset.
Methods
We compared 2 methods of alpha angle measurement (termed “anatomic” and “3-point”) in 59 cadaver femora and 83 cross-table lateral radiographs of asymptomatic subjects. Results were compared using Bland-Altman plots.
Results
Discrepancies of up to 13 degrees were seen between the methods. The 3-point method had an “equalizing effect” by disregarding femoral head position relative to the neck: in femora with high alpha angle, it resulted in lower values than anatomic measurement, and vice versa in femora with low alpha angles. Using the anatomic method, we derived a reference interval for the alpha angle in normal hips in the general population of 30–66 degrees.
Interpretation
We recommend the anatomic method because it also reflects the position of the femoral head on the neck. Consensus and standardization of technique of alpha angle measurement is warranted, not only for planar measurements but also for CT or MRI-based measurements.
doi:10.3109/17453674.2014.899841
PMCID: PMC3967256  PMID: 24650023
9.  Small and similar amounts of micromotion in an anatomical stem and a customized cementless femoral stem in regular-shaped femurs 
Acta Orthopaedica  2014;85(2):152-158.
Background and purpose
High primary stability is important for long-term survival of uncemented femoral stems. Different stem designs are currently in use. The ABG-I is a well-documented anatomical stem with a press-fit design. The Unique stem is designed for a tight customized fit to the cortical bone of the upper femur. This implant was initially developed for patients with abnormal anatomy, but the concept can also be used in patients with normal femoral anatomy. We present 5-year radiostereometric analysis (RSA) results from a randomized study comparing the ABG-I anatomical stem with the Unique femoral stem.
Patients and methods
100 hips with regular upper femur anatomy were randomized to either the ABG-I stem or the Unique femoral stem. RSA measurements were performed postoperatively and after 3, 6, 12, 24, and 60 months.
Results
RSA measurements from 80 hips were available for analysis at the 5-year follow-up. Small amounts of movement were observed for both stems, with no statistically significant differences between the 2 types.
Interpretation
No improvement in long-term stability was found from using a customized stem design. However, no patients with abnormal geometry of the upper femur were included in this study.
doi:10.3109/17453674.2014.899846
PMCID: PMC3967257  PMID: 24650024
10.  Bacterial contamination of the wound during primary total hip and knee replacement 
Acta Orthopaedica  2014;85(2):159-164.
Background and purpose
Previous work has shown that despite preventive measures, intraoperative contamination of joint replacements is still common, although most of these patients seem to do well in follow-up of up to 5 years. We analyzed the prevalence and bacteriology of intraoperative contamination of primary joint replacement and assessed whether its presence is related to periprosthetic joint infection (PJI) on long-term follow-up.
Patients and methods
49 primary total hip replacements (THRs) and 41 total knee replacements (TKRs) performed between 1990 and 1991 were included in the study. 4 bacterial swabs were collected intraoperatively during each procedure. Patients were followed up for joint-related complications until March 2011.
Results
19 of 49 THRs and 22 of 41 TKRs had at least 1 positive culture. Coagulase-negative staphylococci and Staphylococcus aureus were the most common organisms, contaminating 28 and 9 operations respectively. Where information was available, bacteria from 27 of 29 contaminated operations were susceptible to the prophylactic antibiotic administered. 13% of samples gathered before 130 min of surgery were contaminated, as compared to 35% collected after that time. 2 infections were diagnosed, both in TKRs. 1 of them may have been related to intraoperative contamination.
Interpretation
Intraoperative contamination was common but few infections occurred, possibly due to the effect of prophylactic antibiotics. The rate of contamination was higher with longer duration of surgery. It appears that positive results from intraoperative swabs do not predict the occurrence of PJI.
doi:10.3109/17453674.2014.899848
PMCID: PMC3967258  PMID: 24650025
11.  Efficacy of a novel PCR- and microarray-based method in diagnosis of a prosthetic joint infection 
Acta Orthopaedica  2014;85(2):165-170.
Background and purpose
Polymerase chain reaction (PCR) methods enable detection and species identification of many pathogens. We assessed the efficacy of a new PCR and microarray-based platform for detection of bacteria in prosthetic joint infections (PJIs).
Methods
This prospective study involved 61 suspected PJIs in hip and knee prostheses and 20 negative controls. 142 samples were analyzed by Prove-it Bone and Joint assay. The laboratory staff conducting the Prove-it analysis were not aware of the results of microbiological culture and clinical findings. The results of the analysis were compared with diagnosis of PJIs defined according to the Musculoskeletal Infection Society (MSIS) criteria and with the results of microbiological culture.
Results
38 of 61 suspected PJIs met the definition of PJI according to the MSIS criteria. Of the 38 patients, the PCR detected bacteria in 31 whereas bacterial culture was positive in 28 patients. 15 of the PJI patients were undergoing antimicrobial treatment as the samples for analysis were obtained. When antimicrobial treatment had lasted 4 days or more, PCR detected bacteria in 6 of the 9 patients, but positive cultures were noted in only 2 of the 9 patients. All PCR results for the controls were negative. Of the 61 suspected PJIs, there were false-positive PCR results in 6 cases.
Interpretation
The Prove-it assay was helpful in PJI diagnostics during ongoing antimicrobial treatment. Without preceding treatment with antimicrobials, PCR and microarray-based assay did not appear to give any additional information over culture.
doi:10.3109/17453674.2014.889978
PMCID: PMC3967259  PMID: 24564748
12.  Hip-inspired implant for revision of failed reverse shoulder arthroplasty with severe glenoid bone loss 
Acta Orthopaedica  2014;85(2):171-176.
Background and purpose
Glenoid reconstruction and inverted glenoid re-implantation is strongly advocated in revisions of failed reverse shoulder arthroplasty (RSA). Nevertheless, severe glenoid deficiency may preclude glenoid reconstruction and may dictate less favorable solutions, such as conversion to hemiarthropasty or resection arthropasty. The CAD/CAM shoulder (Stanmore Implants, Elstree, UK), a hip arthroplasty-inspired implant, may facilitate glenoid component fixation in these challenging revisions where glenoid reconstruction is not feasible. We questioned (1) whether revision arthroplasty with the CAD/CAM shoulder would alleviate pain and improve shoulder function in patients with failed RSA, not amenable to glenoid reconstruction, (2) whether the CAD/CAM hip-inspired glenoid shell would enable secure and durable glenoid component fixation in these challenging revisions.
Patients and methods
11 patients with failed RSAs and unreconstructable glenoids underwent revision with the CAD/CAM shoulder and were followed-up for mean 35 (28–42) months. Clinical outcomes included the Oxford shoulder score, subjective shoulder value, pain rating, physical examination, and shoulder radiographs.
Results
The average Oxford shoulder score and subjective shoulder value improved statistically significantly after the revision from 50 to 33 points and from 17% to 48% respectively. Pain rating at rest and during activity improved significantly from 5.3 to 2.3 and from 8.1 to 3.8 respectively. Active forward flexion increased from 25 to 54 degrees and external rotation increased from 9 to 21 degrees. 4 patients required reoperation for postoperative complications. No cases of glenoid loosening occurred.
Interpretation
The CAD/CAM shoulder offers an alternative solution for the treatment of failed RSA that is not amenable to glenoid reconstruction.
doi:10.3109/17453674.2014.899850
PMCID: PMC3967260  PMID: 24650026
13.  Sequence of the Essex-Lopresti lesion—a high-speed video documentation and kinematic analysis 
Acta Orthopaedica  2014;85(2):177-180.
Background and purpose
The pathomechanics of the Essex-Lopresti lesion are not fully understood. We used human cadavers and documented the genesis of the injury with high-speed cameras.
Methods
4 formalin-fixed cadaveric specimens of human upper extremities were tested in a prototype, custom-made, drop-weight test bench. An axial high-energy impulse was applied and the development of the lesion was documented with 3 high-speed cameras.
Results
The high-speed images showed a transversal movement of the radius and ulna, which moved away from each other in the transversal plane during the impact. This resulted into a transversal rupture of the interosseous membrane, starting in its central portion, and only then did the radius migrate proximally and fracture. The lesion proceeded to the dislocation of the distal radio-ulnar joint and then to a full-blown Essex-Lopresti lesion.
Interpretation
Our findings indicate that fracture of the radial head may be preceded by at least partial lesions of the interosseous membrane in the course of high-energy axial trauma.
doi:10.3109/17453674.2014.887952
PMCID: PMC3967261  PMID: 24479620
14.  The etiology of short stature affects the clinical outcome of lower limb lengthening using external fixation 
Acta Orthopaedica  2014;85(2):181-186.
Background and purpose
Distraction osteogenesis (DO) has been used to gain height in short statured individuals. However, there have been no studies comparing the clinical outcome of limb lengthening based on the etiology of the short stature. We assessed whether different underlying diagnoses are associated with varied clinical outcomes in these patients.
Methods
We performed a systematic review of the literature pertaining to lower limb lengthening using external fixation for short stature. Clinical outcomes including amount of lengthening, healing index (HI), and complications based on the underlying diagnosis for the short stature were documented.
Results
18 clinical studies were included, with 547 patients who underwent 1,581 lower limb segment lengthening procedures. Mean follow-up was 4.3 years. The average age at lengthening was less for individuals with achondroplasia/hypochondroplasia (A/H) (14.5 years) than for those with Turner’s syndrome (TS) (18.2 years) or with constitutional short stature (CSS) (21.7 years). Mean height gained was greater in patients with A/H (9.5 cm) than in those with TS (7.7 cm) or CSS (6.1 cm) group. The HI was better in A/H (30.8 days/cm) and CSS (32 days/cm) than in TS (45.1 days/cm). The reported complication rate per segment was lower for A/H (0.68) and TS (0.71) than for CSS (1.06).
Interpretation
Patients with A/H tolerated larger amounts of lengthening with fewer complications than those with other diagnoses.
doi:10.3109/17453674.2014.899856
PMCID: PMC3967262  PMID: 24650027
15.  Validity, reliability, and responsiveness of the Self-reported Foot and Ankle Score (SEFAS) in forefoot, hindfoot, and ankle disorders 
Acta Orthopaedica  2014;85(2):187-194.
Background and purpose
The self-reported foot and ankle score (SEFAS) is a questionnaire designed to evaluate disorders of the foot and ankle, but it is only validated for arthritis in the ankle. We validated SEFAS in patients with forefoot, midfoot, hindfoot, and ankle disorders.
Patients and methods
118 patients with forefoot disorders and 106 patients with hindfoot or ankle disorders completed the SEFAS, the foot and ankle outcome score (FAOS), SF-36, and EQ-5D before surgery. We evaluated construct validity for SEFAS versus FAOS, SF-36, and EQ-5D; floor and ceiling effects; test-retest reliability (ICC); internal consistency; and agreement. Responsiveness was evaluated by effect size (ES) and standardized response mean (SRM) 6 months after surgery. The analyses were done separately in patients with forefoot disorders and hindfoot/ankle disorders.
Results
Comparing SEFAS to the other scores, convergent validity (when correlating foot-specific questions) and divergent validity (when correlating foot-specific and general questions) were confirmed. SEFAS had no floor and ceiling effects. In patients with forefoot disorders, ICC was 0.92 (CI: 0.85–0.96), Cronbach's α was 0.84, ES was 1.29, and SRM was 1.27. In patients with hindfoot or ankle disorders, ICC was 0.93 (CI: 0.88-0.96), Cronbach's α was 0.86, ES was 1.05, and SRM was 0.99.
Interpretation
SEFAS has acceptable validity, reliability, and responsiveness in patients with various forefoot, hindfoot, and ankle disorders. SEFAS is therefore an appropriate patient- reported outcome measure (PROM) for these patients, even in national registries.
doi:10.3109/17453674.2014.889979
PMCID: PMC3967263  PMID: 24564747
16.  YKL-40 expression in soft-tissue sarcomas and atypical lipomatous tumors 
Acta Orthopaedica  2014;85(2):195-200.
Background and purpose
YKL-40 is a glycoprotein that is expressed in many types of cancer cells. In some cancers, there is a correlation between high serum YKL-40 levels on the one hand and more aggressive disease and early death on the other. YKL-40 has never been studied in patients with soft-tissue sarcomas (STSs). We investigated whether YKL-40 is expressed in STS tissue and ascertained that the degree of expression is related to survival and/or the histological grade of the malignancy (FNCLCC).
Patients and methods
We included archived tissue from 49 patients (40 with STS and 9 with atypical lipomatous tumor, 20 female and 29 male, mean age 58 (4–89) years) who were treated with tumor resection in 2004 or 2005 at the Department of Orthopedics, Rigshospitalet. The minimum length of follow-up with respect to survival was 5–7 years. Immunohistochemical analysis with anti-YKL-40 antibody using tissue microarray was performed on resected tumors, and a semiquantitative measure of the intensity of YKL-40 staining was performed.
Results
41 of the 49 tumors were positive for YKL-40, and of these, 36 had moderate to intense staining. 24 of the patients died within the follow-up period, and the intensity of YKL-40 staining was significantly higher in tumors from patients who had died in the follow-up period than in tumors from those who survived (p = 0.01). The staining intensity was different for the 3 grades of malignancy (p = 0.004): it was higher in highly malignant tumors (FNCLCC grade 2 and grade 3) than in low-malignancy tumors (grade 1).
Interpretation
YKL-40 is expressed in soft-tissue sarcomas. There is a correlation between expression of YKL-40 in STS and both histological grade of the malignancy and survival. Whether or not YKL-40 expression is an independent prognostic variable could not be determined in the present study.
doi:10.3109/17453674.2014.893496
PMCID: PMC3967264  PMID: 24650028
17.  A single topical dose of erythropoietin applied on a collagen carrier enhances calvarial bone healing in pigs 
Acta Orthopaedica  2014;85(2):201-209.
Background and purpose
The osteogenic potency of erythropoietin (EPO) has been documented. However, its efficacy in a large-animal model has not yet been investigated; nor has a clinically safe dosage. The purpose of this study was to overcome such limitations of previous studies and thereby pave the way for possible clinical application. Our hypothesis was that EPO increases calvarial bone healing compared to a saline control in the same subject.
Methods
We used a porcine calvarial defect model. In each of 18 pigs, 6 cylindrical defects (diameter: 1 cm; height: 1 cm) were drilled, allowing 3 pairwise comparisons. Treatment consisted of either 900 IU/mL EPO or an equal volume of saline in combination with either autograft, a collagen carrier, or a polycaprolactone (PCL) scaffold. After an observation time of 5 weeks, the primary outcome (bone volume fraction (BV/TV)) was assessed with high-resolution quantitative computed tomography. Secondary outcome measures were histomorphometry and blood samples.
Results
The median BV/TV ratio of the EPO-treated collagen group was 1.06 (CI: 1.02–1.11) relative to the saline-treated collagen group. Histomorphometry showed a similar median effect size, but it did not reach statistical significance. Autograft treatment had excellent healing potential and was able to completely regenerate the bone defect independently of EPO treatment. Bony ingrowth into the PCL scaffold was sparse, both with and without EPO. Neither a substantial systemic effect nor adverse events were observed. The number of blood vessels was similar in EPO-treated defects and saline-treated defects.
Interpretation
Topical administration of EPO on a collagen carrier moderately increased bone healing. The dosing regime was safe, and could have possible application in the clinical setting. However, in order to increase the clinical relevance, a more potent but still clinically safe dose should be investigated.
doi:10.3109/17453674.2014.889981
PMCID: PMC3967265  PMID: 24564750
21.  Denosumab and atypical femoral fractures 
Acta Orthopaedica  2014;85(1):1.
doi:10.3109/17453674.2013.859423
PMCID: PMC3940980  PMID: 24171676
22.  Addendum in print 
Acta Orthopaedica  2014;85(1):2.
doi:10.3109/17453674.2014.885353
PMCID: PMC3940981  PMID: 24460106
24.  Atypical fracture of the femur in a patient using denosumab – a case report 
Acta Orthopaedica  2014;85(1):6-7.
doi:10.3109/17453674.2014.885355
PMCID: PMC3940983  PMID: 24460109
25.  Postoperative urinary retention (POUR) in fast-track total hip and knee arthroplasty 
Acta Orthopaedica  2014;85(1):8-10.
doi:10.3109/17453674.2014.881683
PMCID: PMC3940984  PMID: 24460110

Results 1-25 (639)