<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
<rss version="2.0">
  <channel>
    <title>Heijboer, M.P.</title>
    <link>http://repub.eur.nl/res/aut/3290/</link>
    <description>List of Publications</description>
    <language>en</language>
    <image>
      <url>http://repub.eur.nl/static-eur/img/logo.png</url>
      <title>RePub, Erasmus University Rotterdam</title>
      <link>http://repub.eur.nl</link>
    </image>
    <item>
      <title>Correlation between radiological assessment of acute ankle fractures and syndesmotic injury on MRI (Article)</title>
      <link>http://repub.eur.nl/res/pub/33821/</link>
      <pubDate>2012-07-01T00:00:00Z</pubDate>
      <description>Objective: Owing to the shortcomings of clinical examination and radiographs, injury to the syndesmotic ligaments is often misdiagnosed. When there is no indication requiring that the fractured ankle be operated on, the syndesmosis is not tested intra-operatively, and rupture of this ligamentous complex may be missed. Subsequently the patient is not treated properly leading to chronic complaints such as instability, pain, and swelling. We evaluated three fracture classification methods and radiographic measurements with respect to syndesmotic injury. Materials and methods: Prospectively the radiographs of 51 consecutive ankle fractures were classified according to Weber, AO-Müller, and Lauge-Hansen. Both the fracture type and additional measurements of the tibiofibular clear space (TFCS), tibiofibular overlap (TFO), medial clear space (MCS), and superior clear space (SCS) were used to assess syndesmotic injury. MRI, as standard of reference, was performed to evaluate the integrity of the distal tibiofibular syndesmosis. The sensitivity and specificity for detection of syndesmotic injury with radiography were compared to MRI. Results: The Weber and AO-Müller fracture classification system, in combination with additional measurements, detected syndesmotic injury with a sensitivity of 47% and a specificity of 100%, and Lauge-Hansen with both a sensitivity and a specificity of 92%. TFCS and TFO did not correlate with syndesmotic injury, and a widened MCS did not correlate with deltoid ligament injury. Conclusion: Syndesmotic injury as predicted by the Lauge-Hansen fracture classification correlated well with MRI findings. With MRI the extent of syndesmotic injury and therefore fracture stage can be assessed more accurately compared to radiographs. </description>
    </item> <item>
      <title>The development of cam-type deformity in adolescent and young male soccer players (Article)</title>
      <link>http://repub.eur.nl/res/pub/39226/</link>
      <pubDate>2012-05-01T00:00:00Z</pubDate>
      <description>Background: Cam impingement is a well-recognized cause of hip pain and might cause osteoarthritis of the hip. Clinically, cam impingement is mostly observed in young, active male patients, but only a few studies have focused on the manifestation of cam-type deformities during skeletal development.Purpose: To determine the age of onset and prevalence of cam-type deformities in young male soccer players versus controls.Study Design: Cross-sectional study; Level of evidence, 3.Methods: In this study, 89 elite preprofessional soccer players and 92 controls aged 12 to 19 years were included. In the soccer players, range of motion and impingement tests were performed. Both an anteroposterior (AP) pelvic radiograph and a frog-leg lateral radiograph of the hip were obtained according to a standardized protocol. Controls with both an AP pelvic and a frog-leg lateral radiograph and no hip disorders were obtained from radiology databases. The α angle was automatically determined in all radiographs, using a threshold value of 60°to define a cam-type deformity. Further, all radiographs were scored using a 3-point scoring system. The anterosuperior head-neck junction was classified as (1) normal, (2) flattened, or (3) having a prominence. Differences in prevalence were tested using logistic regression. Differences in range of motion were calculated using generalized estimating equations.Results: An α angle &gt;60°was already found at the age of 12 years in some soccer players and controls. A cam-type deformity defined by α angle tended to be more prevalent in soccer players (26%) than in controls (17%; P =.31). In 13% of soccer players, a prominence was visible on radiographs and was first seen at the age of 13 years. The anterosuperior flattening (56% vs 18%, P =.0001) and prominence (13% vs 0%, P &lt;.03) were more prevalent in soccer players than in controls.Conclusion: Cam-type deformities were recognizable and present from the age of 13 years and were more prevalent in soccer players than in their nonathletic peers. Cam-type deformity develops during adolescence and is likely to be influenced by high-impact sports practice. </description>
    </item> <item>
      <title>Tendon structure's lack of relation to clinical outcome after eccentric exercises in chronic midportion Achilles tendinopathy (Article)</title>
      <link>http://repub.eur.nl/res/pub/39362/</link>
      <pubDate>2011-11-01T00:00:00Z</pubDate>
      <description>CONTEXT: Chronic midportion Achilles tendinopathy is a common and hard-to-treat disorder characterized by degenerative changes of the tendon matrix. Ultrasonographic tissue characterization (UTC) was successfully used to quantify structural human Achilles tendon changes. This novel and reliable technique could be used in follow-up studies to relate tendon structure to symptoms.

OBJECTIVE: To quantify structural tendon changes and assess clinical change in patients with tendinopathy.

DESIGN: Prospective observational study.

SETTING: Orthopedic department in a university medical center.

PATIENTS: 23 patients with chronic midportion Achilles tendinopathy.

INTERVENTION: The patients performed a 16-wk home-based eccentric exercise program. An experienced researcher performed the ultrasonographic data collection with the UTC procedure. These data were assessed by a blinded observer. The severity of symptoms was established with the validated Victorian Institute of Sport Assessment-Achilles (VISA-A) questionnaire.

MAIN OUTCOME MEASURES: UTC was performed to quantify tendon structure through measuring the proportion of 4 echo types. Echo types I and II represent more or less organized tendon bundles, and echo types III and IV represent disintegrated tendon structure. On the VISA-A, the total possible score is divided by 100 for a percentage score, with a perfect score of 100. Follow-up was at 2, 8, 16, and 24 wk.

RESULTS: The mean percentage of echo types I and II changed by 0.3% after 24 wk (P = .92, 95% CI -5.8 to 5.3). The mean VISA-A score increased slightly but significantly by 11.3 points after 24 wk (P = .01, 95% CI 2.6-20.0). An increased VISA-A score was not correlated with an increased percentage of echo types I and II (P = .94, r = -.02), and the baseline percentage of echo types I and II did not correlate with an increased VISA-A score (P = .74, r = .07).

CONCLUSIONS: There is no short-term increase in organized tendon structure after eccentric exercises. Tendon structure is not related to symptom severity and cannot be used as a predictor of clinical outcome.

</description>
    </item> <item>
      <title>Risk factors of recurrent hamstring injuries: A systematic review (Article)</title>
      <link>http://repub.eur.nl/res/pub/39358/</link>
      <pubDate>2011-10-19T00:00:00Z</pubDate>
      <description>Background: Although recurrent hamstring injury is a frequent problem with a significant impact on athletes, data on factors determining the risk for a recurrent hamstring injury are scarce. Objective: To systematically review the literature and provide an overview of risk factors for re-injury of acute hamstring muscle injuries. Study design: Prospective studies on risk factors for re-injury following acute hamstring injuries were systematically reviewed. Medical databases and reference lists of the included articles were searched. Two reviewers independently selected potential studies and assessed methodological quality; one reviewer extracted the data. A best-evidence synthesis of all studied risk factors was performed. Results: Of the 131 articles identified, five prospective follow-up studies fulfilled our inclusion criteria. These studies reported a recurrence incidence of 13.9-63.3% in the same playing season up to 2 years after initial injury. Limited evidence for three risk factors and one protective factor for recurrent hamstring injury was found; patients with a recurrent hamstring injury had an initial injury with a larger volume size as measured on MRI (47.03vs 12.42 cm3), more often had a Grade 1 initial trauma (Grade 0: 0-30.4%; Grade 1: 60.9-100%; Grade 2: 8.7%) and more often had a previous ipsilateral anterior cruciate ligament (ACL) reconstruction (66.6% vs 17.1%) independent of graft selection. Athletes in a rehabilitation programme with agility/stabilisation exercises rather than strength/stretching exercises had a lower risk for re-injury (7.7% vs 70%). No significant relationship with re-injury was found for 11 related determinants. There was conflicting evidence that a larger cross-sectional area is a risk factor for recurrent hamstring injury. Conclusions: There is limited evidence that athletes with a larger volume size of initial trauma, a Grade 1 hamstring injury and a previous ipsilateral ACL reconstruction are at increased risk for recurrent hamstring injury. Athletes seem to be at lower risk for re-injury when following agility/stabilisation exercises. Copyright Article author (or their employer) 2011.</description>
    </item> <item>
      <title>Ultrasonographic tissue characterisation of human Achilles tendons: quantification of tendon structure through a novel non-invasive approach (Article)</title>
      <link>http://repub.eur.nl/res/pub/17608/</link>
      <pubDate>2009-08-01T00:00:00Z</pubDate>
      <description>OBJECTIVE: To asses if three-dimensional imaging of the Achilles tendon by Ultrasonographic Tissue Characterisation (UTC) can differentiate between symptomatic and asymptomatic tendons. DESIGN: Case-control study. SETTING: Sports medical department of The Hague medical centre. PATIENTS: Twenty-six tendons from patients with chronic midportion Achilles tendinopathy were included. The "matched" control group consisted of 26 asymptomatic tendons. INTERVENTIONS: Symptomatic and asymptomatic tendons were scanned using the UTC-procedure. One researcher performed the ultrasonographic data-collection. These blinded data were randomised and outcome measures were determined by two independent observers. Main outcome measurements: The raw ultrasonographic images were analysed with a custom-designed algorithm that quantifies the three-dimensional stability of echopatterns, qua intensity and distribution over contiguous transverse images. This three-dimensional stability was related to tendon structure in previous studies. UTC categorizes four different echo-types that represent: I) highly stable; II) medium stable; III) highly variable and IV) constantly low intensity and variable distribution. The percentages of echo-types were calculated and the maximum tendon-thickness was measured. Finally, the inter-observer reliability of UTC was determined. RESULTS: Symptomatic tendons showed less pixels in echo-types I and II than asymptomatic tendons (51.5% versus 76.6%, p&lt;0.001), thus less three-dimensional stability of the echopattern. The mean maximum tendon thickness was 9.2 mm in the symptomatic group and 6.8 mm in the asymptomatic group (p&lt;0.001). The Intra-class Correlation Coefficient (ICC) for the inter-observer reliability of determining the echo-types I+II was 0.95. The ICC for tendon thickness was 0.84. CONCLUSION: UTC can quantitatively evaluate tendon structure and thereby discriminate symptomatic and asymptomatic tendons. As such UTC might be useful to monitor treatment protocols.</description>
    </item> <item>
      <title>Ten year follow-up study comparing conservative versus operative treatment of anterior cruciate ligament ruptures. A matched-pair analysis of high level athletes (Article)</title>
      <link>http://repub.eur.nl/res/pub/16076/</link>
      <pubDate>2009-05-01T00:00:00Z</pubDate>
      <description>OBJECTIVE: To compare long term outcome of highly active patients with anterior cruciate ligament ruptures treated operatively versus non-operatively. DESIGN: We reviewed high level athletes with an anterior cruciate ligament rupture on either MRI or arthroscopic evaluation more than 10 years previously, who were treated conservatively. They were pair-matched with patients who had had an anterior cruciate ligament reconstruction with bone-patella-tendon-bone, with respect to age, gender and Tegner activity score before injury. PARTICIPANTS: In total 50 patients were pair-matched. RESULTS: We found no statistical difference between the patients treated conservatively or operatively with respect to osteoarthritis or meniscal lesions of the knee, as well as activity level, objective and subjective functional outcome. The patients who were treated operatively had a significantly better stability of the knee at examination. CONCLUSION: We conclude that the instability repair using a bone-patella-tendon-bone anterior cruciate ligament reconstruction is a good knee stabilising operation. Both treatment options however show similar patient outcome at 10 year follow up.</description>
    </item> <item>
      <title>Achilles tendinosis: changes in biochemical composition and collagen turnover rate (Article)</title>
      <link>http://repub.eur.nl/res/pub/15468/</link>
      <pubDate>2007-09-01T00:00:00Z</pubDate>
      <description>BACKGROUND: Understanding biochemical and structural changes of the extracellular matrix in Achilles tendinosis might be important for developing mechanism-based therapies. HYPOTHESIS: In Achilles tendinosis, changes occur in biochemical composition and collagen turnover rate. STUDY DESIGN: Descriptive laboratory study. METHODS: From 10 patients undergoing surgery for Achilles tendinopathy, 1 tendinosis biopsy specimen and 1 biopsy specimen of macroscopically healthy tendon tissue adjacent to the lesion were collected. Furthermore, biopsy samples were collected from 3 donors with asymptomatic Achilles tendons. Water content, collagen content, percentage of denatured collagen, amount of lysine hydroxylation, number of enzymatic and nonenzymatic crosslinks, matrix metalloproteinase activity, and matrix metalloproteinase and collagen gene-expression levels were analyzed. RESULTS: In tendinotic lesions, the water content was highest, and collagen content was subnormal with higher amounts of denatured/damaged collagen. Low pentosidine levels in tendinotic tissue indicated the presence of relatively young collagenous matrix. More hydroxylated lysine residues were present in tendinotic samples, but enzymatic crosslinks revealed no differences between tendinotic, adjacent, and healthy samples. In tendinotic specimens, matrix metalloproteinase activity was higher, matrix metalloproteinase gene-expression profile was altered, and collagen type I and III gene expression were upregulated. CONCLUSION: In Achilles tendinosis, the collagen turnover rate is increased, and the natural biochemical composition of the collagenous matrix is compromised. CLINICAL RELEVANCE: Although tendon tissue directly adjacent to an Achilles tendinosis lesion looks macroscopically healthy, histological and biochemical degenerative changes in adjacent tissue are evident, which may have implications for surgical interventions.</description>
    </item> <item>
      <title>Intrinsic differentiation potential of adolescent human tendon tissue: an in-vitro cell differentiation study (Article)</title>
      <link>http://repub.eur.nl/res/pub/10012/</link>
      <pubDate>2007-02-23T00:00:00Z</pubDate>
      <description>Tendinosis lesions show an increase of glycosaminoglycan amount, calcifications, and lipid accumulation. Therefore, altered cellular differentiation might play a role in the etiology of tendinosis. This study investigates whether adolescent human tendon tissue contains a population of cells with intrinsic differentiation potential. METHODS: Cells derived from adolescent non-degenerative hamstring tendons were characterized by immunohistochemistry and FACS-analysis. Cells were cultured for 21 days in osteogenic, adipogenic, and chondrogenic medium and phenotypical evaluation was carried out by immunohistochemical and qPCR analysis. The results were compared with the results of similar experiments on adult bone marrow-derived stromal cells (BMSCs). RESULTS: Tendon-derived cells stained D7-FIB (fibroblast-marker) positive, but alpha-SMA (marker for smooth muscle cells and pericytes) negative. Tendon-derived cells were 99% negative for CD34 (endothelial cell marker), and 73% positive for CD105 (mesenchymal progenitor-cell marker). In adipogenic medium, intracellular lipid vacuoles were visible and tendon-derived fibroblasts showed upregulation of adipogenic markers FABP4 (fatty-acid binding protein 4) and PPARG (peroxisome proliferative activated receptor gamma). In chondrogenic medium, some cells stained positive for collagen 2 and tendon-derived fibroblasts showed upregulation of collagen 2 and collagen 10. In osteogenic medium Von Kossa staining showed calcium deposition although osteogenic markers remained unaltered. Tendon-derived cells and BMCSs behaved largely comparable, although some distinct differences were present between the two cell populations. CONCLUSION: This study suggests that our population of explanted human tendon cells has an intrinsic differentiation potential. These results support the hypothesis that there might be a role for altered tendon-cell differentiation in the pathophysiology of tendinosis.</description>
    </item> <item>
      <title>Successful endoscopic treatment of chronic groin pain in athletes (Article)</title>
      <link>http://repub.eur.nl/res/pub/36509/</link>
      <pubDate>2007-02-01T00:00:00Z</pubDate>
      <description>Background: Chronic groin pain, especially in professional sportsmen, is a difficult clinical problem. Methods: From January 1999 to August 2005, 55 professional and semiprofessional sportsmen (53 males; mean age, 25 ± 4.5 years; range, 17-36 years) with undiagnosed chronic groin pain were followed prospectively. All the patients underwent an endoscopic total extraperitoneal (TEP) mesh placement. Results: Incipient hernia was diagnosed in the study athletes: 15 on the right side (27%), 12 on the left side (22%), and 9 bilaterally (16%). In 20 patients (36%), an inguinal hernia was found: 3 direct inguinal hernias (5%) and 17 indirect hernias (31%). All the athletes returned to their normal sports level within 3 months after the operation. Conclusions: A TEP repair must be proposed to patients with prolonged groin pain unresponsive to conservative treatment. If no clear pathology is identified, reinforcement of the wall using a mesh offers good clinical results for athletes with idiopathic groin pain. </description>
    </item> <item>
      <title>Prevalence of cerebral white matter lesions in elderly people: a population based magnetic resonance imaging study. The Rotterdam Scan Study (Article)</title>
      <link>http://repub.eur.nl/res/pub/9555/</link>
      <pubDate>2001-01-01T00:00:00Z</pubDate>
      <description>OBJECTIVE: White matter lesions are often seen on MR scans of elderly
          non-demented and demented people. They are attributed to degenerative
          changes of small vessels and are implicated in the pathogenesis of
          cognitive decline and dementia. There is evidence that especially
          periventricular white matter lesions are related to cognitive decline,
          whereas subcortical white matter lesions may be related to late onset
          depression. The frequency distribution of subcortical and periventricular
          white matter lesions according to age and sex reported. METHODS: A total
          of 1077 subjects aged between 60-90 years were randomly sampled from the
          general population. All subjects underwent 1.5T MR scanning; white matter
          lesions were rated separately for the subcortical region and the
          periventricular region. RESULTS: Of all subjects 8% were completely free
          of subcortical white matter lesions, 20% had no periventricular white
          matter lesions, and 5% had no white matter lesions in either of these
          locations. The proportion with white matter lesions increased with age,
          similarly for men and women. Women tended to have more subcortical white
          matter lesions than men (total volume 1.45 ml v 1. 29 ml; p=0.33), mainly
          caused by marked differences in the frontal white matter lesion volume
          (0.89 ml v 0.70 ml; p=0.08). Periventricular white matter lesions were
          also more frequent among women than men (mean grade 2.5 v 2.3; p=0.07).
          Also severe degrees of subcortical white matter lesions were more common
          in women than in men (OR 1.1; 95% confidence interval (95% CI) 0.8-1.5)
          and periventricular white matter lesions (OR 1.2; 95% CI 0.9-1.7), albeit
          that none of these findings were statistically significant. CONCLUSIONS:
          The prevalence and the degree of cerebral white matter lesions increased
          with age. Women tended to have a higher degree of white matter lesions
          than men. This may underlie the finding of a higher incidence of dementia
          in women than in men, particularly at later age.</description>
    </item> <item>
      <title>Limited value of arthroscopic evaluation and treatment of painful knee prostheses: a retrospective study of 27 cases (Article)</title>
      <link>http://repub.eur.nl/res/pub/15543/</link>
      <pubDate>1998-11-01T00:00:00Z</pubDate>
      <description>Twenty-seven painful knee replacements were evaluated arthroscopically. The diagnostic and therapeutic value of these arthroscopic procedures was studied retrospectively. In 5 of the 27 cases, the arthroscopy revealed no diagnosis for the pain. Some form of arthroscopic treatment was performed in 20 cases; in 6 of these 20 cases, however, the treatment did not reduce the pain.  Based on these findings, we conclude that the indications for arthroscopic evaluation and treatment of painful knee prostheses are limited.</description>
    </item>
  </channel>
</rss>