Impaction allografting for femoral component revision: clinical update

The technique of cancellous impaction allografting with cement aims to reconstitute a bone-deficient proximal femur while also gaining stable fixation of the femoral prosthesis. Some reports of this technique imply it is a system, requiring not just an exacting surgical method, but also a particular implant design, the polished, double-tapered stem. Other series consider it a surgical technique, and have varied the femoral component design, the method of graft delivery, and other elements of the procedure. Our review evaluates the current literature, with the goal of beginning to ascertain whether published results suggest impaction grafting must be considered a system, requiring a particular stem design, or simply another means to achieve femoral reconstruction in the revision setting. The conclusive answer will require randomized, controlled clinical trials to evaluate particular elements of the procedure, and these studies have yet to be done. However, investigators have shown similarly good short-term to intermediate-term results with various femoral stems at numerous centers. Currently, femoral impaction allografting, whether as a system using particular implant designs or as a surgical technique, is an accepted alternative for revision of a failed femoral component, particularly when bone-stock deficiency is present.     

Cardiac abnormalities in end stage renal failure and anaemia

Thirteen anaemic children on dialysis were assessed to determine the incidence of cardiac changes in end stage renal failure. Nine children had an increased cardiothoracic ratio on radiography. The electrocardiogram was abnormal in every case but no child had left ventricular hypertrophy as assessed by voltage criteria. However, left ventricular hypertrophy, often gross, was found on echocardiography in 12 children and affected the interventricular septum disproportionately. Cardiac index was increased in 10 patients as a result of an increased left ventricular stroke volume rather than heart rate. Left ventricular hypertrophy was significantly greater in those on treatment for hypertension and in those with the highest cardiac index. Abnormal diastolic ventricular function was found in 6/11 children. Children with end stage renal failure have significant cardiac abnormalities that are likely to contribute to the high cardiovascular mortality in this group. Anaemia and hypertension, or its treatment, probably contribute to these changes. Voltage criteria on electrocardiogram are of no value in detecting left ventricular hypertrophy. Echocardiography must be performed, with the results corrected for age and surface area, in order to detect and follow these abnormalities.     

Presentation of obstructive left heart malformations in infancy.

This study documents the presentation of acutely life threatening congenital heart disease in infancy in order to assess the performance of screening examinations soon after birth and at 6 weeks of age. All cases of obstructive left heart malformations presenting in infancy in one health region from 1987-91 were analysed retrospectively. Altogether, 120 infants presented with either hypoplastic left heart syndrome, interruption of the aortic arch, coarctation of the aorta, or aortic valve stenosis. Twelve became symptomatic or died within 24 hours. Thirty four had an abnormal neonatal examination, eight of whom were referred. Six more became symptomatic before discharge. Ninety four babies went home, 51 developed heart failure before 6 weeks, and another seven died without diagnosis. Twenty five of 36 (69%) reaching 6 weeks without diagnosis had a second examination which was abnormal in 17. Two babies died undiagnosed after 6 weeks and the other 18 presented at up to 11 months of age. The neonatal and 6 week examinations perform poorly as screening tests for congenital heart disease. A normal neonatal examination does not exclude life threatening congenital heart disease.     

Examining child restraint use and barriers to their use: lessons from a pilot study

OBJECTIVE: To determine the suitability of four research methods to measure the rate of child restraint device (CRD) use and incorrect use in New Zealand and obtain data on barriers to CRD use. DESIGN AND SETTING: To assess the rates of CRD use among vehicles carrying children 8 years of age and under, two methods were piloted-namely, an unobtrusive observational survey and a short interview and close inspection. A self administered questionnaire and focus group interviews were also piloted to assess CRD use, reasons for use and non-use, and to obtain information on barriers to their use. Respondents to all methods except the focus groups were approached in supermarket car park sites at randomly selected times. Focus groups were established with parents identified through early childhood organisations. All methods were assessed on criteria related to efficiency, representativeness, and ability to obtain the necessary data. RESULTS: The observational survey provided a simple method for identifying rates of CRD use, while the self administered questionnaire obtained data on demographic characteristics and reported the installation and use/non-use of CRDs. The interview/inspection addressed all the questions of both the above methods and enabled incorrect CRD use to be examined. The focus groups provided the most meaningful information of all methods on barriers to CRD use. DISCUSSION: and conclusion: Advantages and limitations of these methods are discussed and some refinements of the original instruments are proposed. The interview/inspection and focus group methods were identified as being more appropriate for efficiently obtaining reliable data on CRD use and identification of barriers to CRD use.     

Relaxin levels in ovum donation pregnancies

STUDY OBJECTIVE: To investigate the relative contributions of the corpus luteum (CL) and the placenta to the circulating levels of relaxin during pregnancy. PATIENTS: Forty-one patients in whom pregnancy had been achieved by ovum donation. RESULTS: Relaxin was not detected in the serum of 36 patients; in the remaining 5, although it was detectable, the levels were markedly reduced when compared with those in normal pregnancies. CONCLUSION: These results demonstrate that the CL is essential for the maintenance of normal circulating levels of relaxin during pregnancy.     

Bone density effects of continuous estrone sulfate and varying doses of medroxyprogesterone acetate. Ogen/Provera Study Group.

OBJECTIVE: To establish the optimum oral daily dose of medroxyprogesterone acetate with estrone sulfate for 2 years to maintain bone density. METHODS: A multicenter, double-blind study involved 568 postmenopausal women given estrone sulfate, 1.25 mg, and randomized to receive 2.5, 5, or 10 mg of medroxyprogesterone acetate. Bone density analyses of the lumbar spine and femoral neck were done at baseline and 12 and 24 months. RESULTS: There was a significant increase from baseline to 24 months in mean lumbar spine (4.0% +/- 0.27%) and femoral neck (3.2% +/- 0.28%) bone density, with no significant differences between the treatment groups. Factors most influencing bone density changes were baseline bone density and treatment duration. Significant increases were seen in the spine over 2 years; in the hip, those occurred in the first 12 months only. In both sites, lower baseline bone density resulted in greater increases. In the spine only, no previous hormone replacement therapy, higher body mass index, more than 2 years postmenopause, and nonsmoking resulted in greater gains. Once those covariates and center-to-center variations were corrected for, in the spine, the 10-mg group had smaller increases than the other groups. Changes were unrelated to age, parity, calcium, and alcohol intakes in either site. CONCLUSION: Daily estrone sulfate, 1.25 mg, with 2.5, 5, or 10 mg medroxyprogesterone acetate was effective for preventing bone loss in postmenopausal women.