PubMed Health⌕ Search

Biomedical subjects

Wun-Jer Shen

Publications and source records attributed to Wun-Jer Shen.

6 recordsLinked to original sources
PubMed2005

Anterior subtalar dislocation: a case report.

Anterior subtalar dislocations are extremely rare. To our knowledge, six cases have been reported in detail in the literature, but for only two of these was an anteroposterior view radiograph used to confirm the diagnosis. We report a case of anterior subtalar dislocation in which the posterior tibialis tendon was incarcerated in the talonavicular joint and that required an open reduction. We discuss the diagnosis, mechanism, and treatment.

Accidental Falls↗
PubMed2005

Cementless total hip arthroplasty and limb-length equalization in patients with unilateral Crowe type-IV hip dislocation.

BACKGROUND: Total hip arthroplasty in patients with unilateral congenital high dislocation of the hip (Crowe type IV) presents many challenges, including the problem of a marked limb-length discrepancy. The purpose of this retrospective study was to analyze the results of total hip replacement with limb-length equalization in these patients. METHODS: From 1988 to 1996, fifty-six patients (forty-seven women and nine men) with unilateral Crowe type-IV dislocation of the hip were treated with a cementless total hip arthroplasty at a mean age of 35.4 years. The preoperative limb-length discrepancy averaged 4.9 cm. Prior to the total hip arthroplasty, forty-eight patients with a limb-length discrepancy of >4.0 cm underwent iliofemoral distraction with use of an external fixator for eight to seventeen days. The acetabular cup was placed in the anatomical position in every patient. Shortening femoral osteotomies were not required. RESULTS: The iliac fixator pins loosened in six patients. No patient had a pin-site infection, hip joint infection, or nerve palsy. At the time of follow-up, at an average of 147.2 months, the Harris hip score averaged 90.2 points. Overall, the mean lengthening after the total hip arthroplasty was 4.6 cm. There were no revisions of the femoral stem. Nine cups were revised, four because of polyethylene wear and five because of loosening. CONCLUSIONS: We were able to safely place the acetabular cup at the anatomical position without femoral shortening by bringing the femoral head to the normal level preoperatively; thus, we could restore nearly normal limb length. We believe that our twelve-year results are similar to those of total hip arthroplasty in patients without dysplasia.

Adult↗
PubMed2005

The use of alendronate to prevent early collapse of the femoral head in patients with nontraumatic osteonecrosis. A randomized clinical study.

BACKGROUND: Osteonecrosis of the femoral head is the most common diagnosis leading to total hip arthroplasty in young adults. Joint-preserving treatment options have been mainly surgical, with inconsistent results. Alendronate (a bisphosphonate agent) has been shown to lower the prevalence of vertebral compression fractures and could potentially retard the collapse of an osteonecrotic femoral head. The purpose of this study was to test the effect of alendronate in preventing early collapse of the femoral head in patients with nontraumatic osteonecrosis. METHODS: Forty patients with Steinberg stage-II or III nontraumatic osteonecrosis of the femoral head and a necrotic area of >30% (class C) were randomly divided into alendronate and control groups of twenty patients each. Patients in the alendronate group took 70 mg of alendronate orally per week for twenty-five weeks, while the patients in the control group did not receive this medication or a placebo. The patients were observed for a minimum of twenty-four months. Harris hip scores, plain radiographs, and magnetic resonance imaging scans were obtained. RESULTS: During the study period, only two of twenty-nine femoral heads in the alendronate group collapsed, whereas nineteen of twenty-five femoral heads in the control group collapsed (p < 0.001). One hip in the alendronate group underwent total hip arthroplasty, whereas sixteen hips in the control group underwent total hip arthroplasty (p < 0.001). CONCLUSIONS: Alendronate appeared to prevent early collapse of the femoral head in the hips with Steinberg stage-II or IIIC nontraumatic osteonecrosis. A longer duration of follow-up is needed to confirm whether alendronate prevents or only retards collapse. LEVEL OF EVIDENCE: Therapeutic Level I.

Adult↗
PubMed2002

Failure of hydroxyapatite-coated acetabular cups. Ten-year follow-up of 85 Landos Atoll arthroplasties.

Between March 1990 and May 1991 we performed 85 primary total hip replacements in 74 patients using the Landos Atoll hydroxyapatite (HA)-coated cup and the Corail HA-coated stem. The patients were followed up for a mean of ten years. Of the 85 cups, 26 (31%) have already been revised and a further six are radiologically unstable and awaiting revision. Two femoral stems have been revised for infection without loosening. The retrieved acetabular cups were studied by SEM and image-processing techniques to quantify the amount of residual HA on the cup. This was correlated with the clinical variables and modes of failure. The residual HA (as a percentage of the surface) on the loose cups correlated negatively with the duration of implantation (r = -0.732, p < 0.001). Six cups were stable at revision and had more residual HA coating than those which were loose (p < 0.01). The rate of failure of the Landos Atoll HA-coated, smooth hemispherical cup with screw fixation is unacceptably high. Resorption of the HA coating is markedly increased in loose cups compared with stable cups. HA coating cannot substitute for stable mechanical fixation.

Adult↗
PubMedDate not supplied

Ionic versus nonionic paramagnetic contrast media in differentiating between postoperative scar and recurrent disk.

BACKGROUND AND PURPOSE: In theory, ionic solutes diffuse more slowly in cartilage than do nonionic solutes. We tested the hypothesis that the contrast ratio between scar and recurrent disk fragment on MR images is greater after IV administration of an ionic rather than a nonionic contrast medium when a clinical dose is used. METHODS: Twenty patients who had recurrent lumbar disk herniation were enrolled in this study. The enhancement of epidural scar and recurrent disk fragment was measured at 5, 25, 40, and 50 min after IV injection of ionic and nonionic contrast media (0.1 mmol/kg) RESULTS: The enhancement was consistently and significantly higher for scar than for recurrent disk fragment, although the contrast ratio between scar and recurrent disk fragment decreased between 5 and 50 min after the administration of each contrast medium. No significant difference was shown between ionic and nonionic contrast media in the enhancement of recurrent disk fragment at 5, 25, 40, and 50 min after injection. The contrast ratio between scar and recurrent disk fragment was not a significant difference at 5, 25, and 40 min after administration of both contrast media. At 50 min, the contrast ratio between scar and recurrent disk fragment was 1.32 +/- 0.41 with ionic contrast medium and 1.20 +/- 0.56 with nonionic contrast medium. The difference was significant. CONCLUSION: The contrast ratio between scar and recurrent disk fragment is affected by the timing of the imaging. Images obtained immediately after the injection of each contrast medium showed a greater contrast ratio than did delayed images. In addition, with the ionic medium, this difference was greater than with nonionic medium at 5, 25, 40, and 50 min after injection and that difference reached statistical significance at 50 min.

Cicatrix↗