Stem fixation in revision total knee arthroplasty: a comparative analysis

Methods of stem fixation are a controversial aspect of revision TKA. We sought to determine which technique was superior by reviewing 475 revision TKAs done between 1986 and 2000. Of these 475 revisions, 286 major component revisions were done using 484 extended stems for fixation. Patients who died, patients who had less than 2 years follow up, or patients who had diaphyseal engaging stems were excluded from the study. The final data set included 113 revision TKAs with 202 metaphyseal engaging stems. Of the 202 stems, 107 were cemented whereas 95 were press-fit metaphyseal engaging stems. One hundred one of these were femoral stems and 101 were tibial stems. Using a modified Knee Society radiographic scoring system, 100 (93%) of the 107 implants with cemented stems were considered stable, seven (7%) were categorized as possibly loose requiring close followup, and none were loose. Of the 95 implants placed with cementless stems, only 67 (71%) were categorized as stable. Eighteen (19%) were possibly loose requiring close followup and 10 (10%) were loose (two tibial and eight femoral implants). We currently would urge caution in using cementless metaphyseal engaging stems for fixation in revision TKA.     

Individual differences in nicotine intake per cigarette.

The increase in levels of blood nicotine that occurs from smoking a single cigarette, sometimes referred to as a "nicotine boost," is an individualized measure of how much nicotine has been extracted from smoking a cigarette. This study investigated the demographic, smoking status, and psychological predictors of nicotine boost in a sample of 190 treatment-seeking smokers. Boost was assessed by comparing plasma nicotine levels before and after participants smoked one of their own brand cigarettes ad libitum. Positive affect (mood) was a significant positive predictor of nicotine boost, controlling for baseline cotinine levels and cigarette brand (Federal Trade Commission) nicotine delivery. However the proportion of variability accounted for in the model was relatively small (5%). Future research on individual differences in nicotine boost is warranted to clarify the role of psychological, physiological, and cigarette-related determinants.     

The multifractionated, twice-weekly dose schedule for a three-drug chemotherapy regimen: a phase I-II study of paclitaxel, cisplatin, and vinorelbine

BACKGROUND: Paclitaxel, cisplatin, and vinorelbine are three important antineoplastic drugs with different mechanisms of cell kill. A combination of these three drugs potentially could have additive therapeutic effects. METHODS. The three-drug combination (designated TPN) was administered on a twice-weekly (Monday/Thursday; Tuesday/Friday) schedule for 3 weeks, with cycles repeated every 28 days. The Phase I design utilized a dose de-escalation schema in which the maximum tolerated dose was defined by a patient's ability to complete 6 doses (a full cycle) without interruption for hematologic Grade 3 or 4 toxicity. RESULTS: Twenty-seven patients received a total of 42 evaluable courses of the 3-drug regimen. The cisplatin dose was fixed at 15 mg/M2/fraction. The paclitaxel dose was first fixed at 50 mg/M2/fraction, and venorelbine was delivered at 3 dose levels per fraction: 10, 7.5, and 5 mg/M2. Paclitaxel then was de-escalated to 40 mg/M2/fraction, and the same 3 dose levels of vinorelbine were evaluated. The dose-limiting toxicity was neutropenia. Using fixed doses of paclitaxel at 40 mg/ M2/fraction and cisplatin at 15 mg/M2, the optimal dose fraction for vinorelbine was 7.5 mg/M2, defined as the dose that allowed > 67% of patients to complete 3 weeks (6 consecutive doses) of therapy. Using paclitaxel at 50 mg/M2/fraction (cisplatin at 15 mg/M2/fraction), the optimal dose of vinorelbine was 5 mg/M2/fraction. Tumor responses were observed in 13 patients: 2 with unknown primary, 1 with esophageal carcinoma, 6 with nonsmall cell lung carcinoma, and 3 with breast carcinoma. Grade 2 neurologic (sensory) toxicity was observed in 5 patients. CONCLUSIONS: TPN administered according to a twice-weekly dosing scheme can be delivered with acceptable toxicity. The dose intensity for paclitaxel (60-75 mg/M2/week), cisplatin (22 mg/M2/week), and vinorelbine (15 mg/M2/week) is > 50% of the single agent dose intensity for the component agent. Recommended Phase II or Phase III trials could utilize dose fractions of paclitaxel, cisplatin, and vinorelbine at either 50, 15, and 5 mg/M2/fraction or 40, 15, and 7.5 mg/M2/fraction in this twice-weekly, multifractionated dose schedule.     

Effect on platelet function of hypoalbuminemia in peritoneal dialysis

Chronic renal failure is associated with functional platelet defects. Peritoneal dialysis is associated with improvement in platelet function. This study demonstrates that the hypoalbuminemia resulting from peritoneal dialysis may account for part of the improvement. Platelet aggregation was measured when plasma albumin was less than 3 g/dl and again when the albumin level was raised to greater than 4 g/dl. Normal albumin levels were associated with decreased platelet function when the slope of aggregation to ADP and epinephrine were used as the study parameters. Patients with peritoneal dialysis given albumin to correct their plasma albumin level also acquired reduced platelet aggregation.     

Osteochondritis dissecans of the knee: sonographically guided percutaneous drilling.

OBJECTIVE: The purpose of this study was to present a procedure for sonographically guided percutaneous drilling in the treatment of a case of osteochondritis dissecans (OD) of the knee. METHODS: A 14-year-old boy had OD of the external femoral condyle. Conventional radiography, magnetic resonance imaging, and sonography revealed the osteochondral lesion. RESULTS: This study showed the utility of sonography both in the treatment of OD through percutaneous drilling and in follow-up. CONCLUSIONS: On the basis of the good results obtained in the case described here, it is thought that sonographically guided percutaneous drilling may be a good alternative to arthroscopic drilling in cases of early OD lesions without displacement of the fragment.