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W J Willems

Publications and source records attributed to W J Willems.

At least 19 recordsLinked to original sources
PubMed2006

Mid-term results of arthroscopic reconstruction in chronic posterior cruciate ligament instability.

The purpose of this study was to evaluate the clinical results of arthroscopic single bundle posterior cruciate ligament (PCL) reconstruction in patients with chronic PCL instability not responding to conservative treatment. 18 patients were available for follow-up with an average elapsed time of 3 years between onset of injury and surgery and an average duration of 3.3 years between reconstruction and evaluation. The clinical results were investigated using the IKDC form, the Tegner rating system, a subjective evaluation, and the VAS for pain rating. The presence of femoral degenerative changes correlated strongly to the elapsed time between injury and operation (P<0.05). Before surgery all patients were graded D (severely abnormal) using the IKDC evaluation form. The final IKDC score at follow-up resulted in grade A (normal) in five patients (28%), grade B (nearly normal) in eight patients (44%), grade C (abnormal) in four patients (22%) and grade D (severely abnormal) in one patient (6%). The VAS score for pain rating revealed very few complaints of pain and it demonstrated a strong correlation between the subjective evaluation and the Tegner rating score (P<0.01). Evaluation of the Tegner score resulted in a significant improvement after surgery when compared to the situation prior to operation (P<0.01). Although there still is some controversy on the indication for treatment of PCL injury, we conclude on the basis of our findings that arthroscopic reconstruction of symptomatic chronic PCL instability, not responding to conservative therapy, can be greatly beneficial.

Achilles Tendon↗
PubMed2004

Satisfactory cross cultural equivalence of the Dutch WOMAC in patients with hip osteoarthritis waiting for arthroplasty.

BACKGROUND: Cross cultural validity is of vital importance for international comparisons. OBJECTIVE: To investigate the validity of international Dutch-English comparisons when using the Dutch translation of the Western Ontario and McMaster Universities osteoarthritis index (WOMAC). PATIENTS AND METHODS: The dimensionality, reliability, construct validity, and cross cultural equivalence of the Dutch WOMAC in Dutch and Canadian patients waiting for primary total hip arthroplasty was investigated. Unidimensionality and cross cultural equivalence was quantified by principal component and Rasch analysis. Intratest reliability was quantified with Cronbach's alpha, and test-retest reliability with the intraclass correlation coefficient. Construct validity was quantified by correlating sum scores of the Dutch WOMAC, Arthritis Impact Measurement Scales (Dutch AIMS2), Health Assessment Questionnaire (Dutch HAQ), and Harris Hip Score (Dutch HHS). RESULTS: The WOMAC was completed by 180 Dutch and 244 English speaking Canadian patients. Unidimensionality of the Dutch WOMAC was confirmed by principal component and Rasch analysis (good fit for 20/22 items). The intratest reliability of the Dutch WOMAC for pain and physical functioning was 0.88 and 0.96, whereas the test-retest reliability was 0.77 and 0.92, respectively. Dutch WOMAC pain sum score correlated 0.69 with Dutch HAQ pain, and 0.39 with Dutch HHS pain. Dutch WOMAC physical functioning sum score correlated 0.46 with Dutch AIMS2 mobility, 0.62 with Dutch AIMS2 walking and bending, 0.67 with Dutch HAQ disability, and 0.49 with Dutch HHS function. Differential item functioning (DIF) was shown for 6/22 Dutch items. CONCLUSIONS: The Dutch WOMAC permits valid international Dutch-English comparisons after correction for DIF.

Aged↗
PubMed1999

Sonography and magnetic resonance imaging equivalent for the assessment of full-thickness rotator cuff tears.

OBJECTIVE: To investigate the diagnostic value of sonography (SG) and magnetic resonance imaging (MRI) in the assessment of full-thickness rotator cuff tears (RCTs). METHODS: Twenty-one consecutive, otherwise healthy patients with noninflammatory unilateral chronic (>3 months) shoulder complaints due to a possible full-thickness RCT were studied (9 women and 12 men, mean +/- SD age 56 +/- 12). According to standardized procedures, SG was performed by both a radiologist and a rheumatologist, and MRI was evaluated by 2 radiologists. All assessors were blinded to the patient's diagnosis. Within 3 weeks after SG and MRI, arthroscopy was performed. SG, MRI, and arthroscopy results were scored as negative or positive for the presence of a full-thickness RCT. The result of surgical inspection was used as the "gold standard." RESULTS: For full-thickness RCTs, the sensitivity was 0.81 for SG and 0.81 for MRI. The specificity was 0.94 for SG and 0.88 for MRI. The positive predictive value was 0.96 for SG and 0.91 for MRI. The negative predictive value was 0.77 for SG and 0.74 for MRI. Accuracy was 0.86 for SG and 0.83 for MRI. CONCLUSION: Full-thickness RCTs can be identified accurately by both SG and MRI. Because of its low cost and because it can be performed in the rheumatology unit, SG seems to be a promising diagnostic tool for use by the rheumatologist.

Adult↗
PubMed1998

[One hundred years of orthopedics in Netherlands. V. Arthroscopy].

Since the early eighties arthroscopy has become an important part of orthopaedics. Virtually every joint can be examined with an arthroscope. Apart from the diagnostic possibilities, an increasing number of arthroscopically guided surgical operations are possible. Knee arthroscopy can be used therapeutically for many conditions, including meniscal lesions, refractory synovitis, cruciate ligament lesions, tibial plateau fractures and osteochondral defects; in the shoulder it can be applied to lesions of the glenoid lip or the rotator cuff; in the ankle and foot, for osteochondral fractures and creation of an arthrodesis; in the wrist, for treatment of instability, intra-articular distal fractures of the radius and the carpal tunnel syndrome; in the hip, for removal of loose bodies and in the spine, for the performance of discectomy. Advantages over conventional open operations are smaller proportions of complications (< 2%), shorter hospital stay and more rapid rehabilitation. The areas of indication are defined in guidelines issued by the orthopaedic societies themselves; most orthopaedic surgeons follow these guidelines. A possibility for the future is use of laser in interventions on joints.

Arthroscopes↗
PubMed1998

Arthroscopic anterior cruciate ligament reconstruction with bone-patellar tendon-bone allograft or autograft. A prospective study with an average follow up of 4 years.

A prospective study was performed with 36 patients who underwent an anterior cruciate ligament (ACL) reconstruction with the use of a fresh-frozen bone-patellar tendon-bone (BPTB) allograft. A group of 26 patients who underwent the same operation conducted by the same surgeon in the same period but with the use of an autograft BPTB served as controls. The average follow-up was 46 (range 30-64) months in the allograft group and 52 (range 42-74) months in the autograft group. The allograft group consisted of 17 men and 19 women with a mean age of 28 years (mean trauma to reconstruction interval was 55 months). The autograft group consisted of 9 men and 17 women with a mean age of 28 years (mean trauma to reconstruction interval was 30 months). Clinical and functional evaluation was performed according to the IKDC guidelines. Analysis of tibial tunnel placement with respect to the Blumenstaat line on a lateral radiograph with the knee in hyperextension was done in relation to an extension deficit and clinical score. In the autograft group 18 (70%) patients had a normal or nearly normal knee and 8, a fair result. In the allograft group 30 (85%) patients had a normal or nearly normal knee, 5 (13%) patients had a fair result, and one (2%) knee was poor. The difference between the two groups was not significant. The allograft BPTB is a good alternative graft in ACL reconstruction.

Adolescent↗
PubMed1993

The uncemented Gerard bipolar double-cup arthroplasty of the hip. A five- to 11-year follow-up study.

Between 1978 and 1984, 183 hips in 154 patients with the uncemented Gerard double-cup arthroplasty were resurfaced. The clinical and radiographic results of the 106 original arthroplasties were reviewed after a median follow-up period of 98 months. Although many of these patients had clinically improved immediately, the Harris Hip score decreased significantly in most hips in subsequent years. No correlation was found between the clinical score and radiographic complications. Major revision surgery with removal of the double cup was performed in 54 of 183 patients, making the cumulative success rate after 132 months only 48%. Survival was significantly greater in patients younger than 50 years of age and in patients with a low body weight (Quetelet index less than 25). This high failure rate eliminates the Gerard double-cup arthroplasty, except possibly for the patient with a destructive inflammatory arthropathy for whom there are no other surgical alternatives.

Adult↗
PubMed1991

[Arthroscopic treatment of anterior (sub)luxation of the shoulder].

Seventeen patients with a recurrent traumatic anterior shoulder (sub)luxation were operated on by means of arthroscopic capsulorrhaphy. Follow-up averaged 15 months. One patient showed a recurrent subluxation. Complications were rare and only minor. At follow-up the shoulder function was practically normal. All patients were satisfied with the results of the treatment. Nearly all patients resumed their athletic activities at the previous level. Although this method is still in its experimental phase the results of this 'closed' arthroscopic procedure are very satisfactory; and this technique appears promising.

Adult↗
PubMed1988

Histopathologic evaluation in failed Gerard double cup arthroplasty.

Fifteen femoral head remnants were removed at revision of an uncemented double cup arthroplasty and were investigated by histological methods. Nine showed resorption of the head, partly due to osteoporosis by stress protection, preexistent pseudocysts, or osteonecrosis. Necrosis was frequently seen in the apicocranial area, and in six cases extended into deeper areas. One failure was attributed to synovitis caused by polyethylene debris. A smooth collagenous membrane developed at both the femoral head and the acetabular interfaces. In some cases metaplasia into cartilage and osteophytes developed at the cup rim.

Adult↗
PubMed1986

Vascular smooth muscle transmembrane potentials during hypotensive stress.

Although transmembrane potential (Em) appears to be an important regulator of vascular smooth muscle (VSM) contractile force in vivo, little is known of the electrophysiological changes in VSM during low flow states. In rats, VSM in small mesenteric veins depolarizes in the compensatory stage of hemorrhagic hypotension while the onset of peripheral vascular decompensation is associated with VSM hyperpolarization. Pretreatment with 30 mg/kg i.v. of methylprednisolone prevents the Em changes in mesenteric veins of hemorrhaged rats and reduces the depolarization of isolated vessels in response to norepinephrine, suggesting that some therapeutic agents may act by modifying the electrophysiological responses of VSM during the stress. Finally, adrenergic depolarization under resting conditions may contribute to a reduced ability of spontaneously hypertensive rats (SHR) to tolerate blood loss by reducing their compensatory venoconstrictor reserve relative to normotensive WKY controls. Although these observations suggest that vascular responses to hypotensive stress are related to the effects of the sympathetic nervous system upon VSM Em, further studies are required fully to elucidate the relative role of Em-dependent and Em-independent mechanisms in controlling active VSM tone during low flow states.

Animals↗
PubMed1985

Neer arthroplasty for humeral fracture.

The Neer arthroplasty was performed in 10 patients with four-part proximal humeral fractures. The average follow-up was 2.5 years. No serious complications occurred. All but one became pain-free, but only four were classified as excellent or satisfactory. Videofluoroscopy revealed only minimal gleno-humeral movement in most cases.

Adult↗
PubMed1984

Sodium kinetics and membrane potential in aorta of magnesium-deficient rats.

In light of the important role of magnesium (Mg) in vascular smooth muscle function, this study was undertaken to examine effects of dietary Mg deficiency on membrane potential (Em), sodium (Na) efflux and distribution, and total ion content in rat aorta. Rats were fed either Mg-sufficient or Mg-deficient diets for 30 days. The aortic arch was removed and a segment incubated in 22Na to monitor kinetics of Na efflux. Another segment was used for measurement of Em under control conditions and during ouabain suffusion. Total tissue water and ion content were also determined. Results of this work indicate that, in aorta from Mg-deficient rats, Em was less polarized and Na accumulated intracellularly. Although the Em in Mg-deficient aorta was not affected by ouabain, which suggested Na-K pump inhibition, Na efflux was greater in Mg-deficient aorta, suggesting increased passive permeability changes to Na as the mechanism responsible for these changes.

Animals↗
PubMed1982

Sympathetic supraspinal control of venous membrane potential in spontaneous hypertension in vivo.

To clarify the mechanisms controlling mesenteric venous membrane potential (Em) in spontaneously hypertensive rats (SHR) and Wistar-Kyoto normotensive rats (WKY), Em was measured in vivo using flexibly mounted glass microelectrodes. Venous diameters were also measured. Ems under control conditions were significantly less in SHR. alpha-Adrenergic blockade with phenoxybenzamine (PBZ) significantly dilated and hyperpolarized SHR small veins but failed to alter the membrane potential of WKY small veins. After blockade with PBZ, membrane potentials were similar in both strains. Propranolol suffusion failed to alter the SHR membrane potential but depolarized WKY small veins. During blockade with PBZ, propranolol depolarized venous membranes equally in both strains. Membrane potentials after spinal section were similar in both strains and equal to the Ems during total adrenergic blockade. The data indicate that, in SHR, the relatively depolarized Em derives from altered alpha-adrenergic input. In SHR, alpha-adrenergic input appears to exert its depolarizing effect, at least in party, by interfering with the expression of endogenous, beta-adrenergic hyperpolarization. The beta-adrenergic influence, like the alpha-adrenergic input in SHR, is dependent on intact supraspinal pathways.

Animals↗
PubMed1982

Effect of tetrodotoxin on membrane potentials and active tone in vascular smooth muscle.

The suitability of tetrodotoxin (TTX) for studies of the neural control of vascular smooth muscle (VSM) tone in the microcirculation was evaluated by determining 1) whether TTX blockade of neural input to adrenergically innervated VSM is reversible and 2) whether TTX depresses active VSM tone directly. Diameters of rat mesenteric veins and third- and fourth-order arterioles of the hamster cheek pouch were measured by image splitting. VSM transmembrane potentials (Em) were measured with microelectrodes in rat mesenteric veins. In the veins TTX suffusion (10(-6) g/ml) resulted in dilation and reversible Em hyperpolarization. TTX also reversibly blocked the venoconstrictor response to perivascular nerve stimulation. TTX had no effect on the resting tone of hamster arterioles or on arteriolar constriction in response to increased oxygen availability. TTX did not affect the response to norepinephrine in either preparation. This study indicates that TTX specifically and reversibly blocks VSM responses to neural activation but that it has no direct depressant effect on resting VSM tone or active constriction in response to nonneural activation.

Animals↗