Cell adhesion to plasma electrolytic oxidation (PEO) titania coatings, assessed using a centrifuging technique.

The adhesion of bovine chondrocytes and human osteoblasts to three titania-based coatings, formed by plasma electrolytic oxidation (PEO), was compared to that on uncoated Ti-6Al-4V substrates, and some comparisons were also made with plasma sprayed hydroxyapatite (HA) coatings. This was done using a centrifuge, with accelerations of up to 160,000 g, so as to induce buoyancy forces that created normal or shear stresses at the interface. It is shown that, on all surfaces, it was easier to remove cells under normal loading than under shear loading. Cell adhesion to the PEO coatings was stronger than that on Ti-6Al-4V and similar to that on HA. Cell proliferation rates were relatively high on one of the PEO coatings, which was virtually free of aluminium, but low on the other two, which contained significant levels of aluminium. It is concluded that the Al-free PEO coating offers promise for application to prosthetic implants.

Occupational therapy task observation scale (OTTOS): a rapid method for rating task group function of psychiatric patients.

OBJECTIVE: We designed a simple rating instrument, the Occupational Therapy Task Observation Scale (OTTOS), to facilitate evaluation and documentation of patient performance during occupational therapy task groups and to improve the communication between occupational therapists and other treatment team members. METHOD: After analysis of other rating instruments, a preliminary version of OTTOS was designed, extensively field tested, and further modified. Interrater reliability was determined, and validity was tested against three established rating instruments: the Bay Area Functional Performance Evaluation, the Comprehensive Occupational Therapy Evaluation Scale, and the Milwaukee Evaluation of Daily Living Skills. RESULTS: The final version of OTTOS contains two parts, 10 items for evaluation of specific task functions and 5 items for rating general behavior. Field use demonstrated that the scale successfully tracked changes in functional capacity and included most facets of patient function evaluated during task groups. Use of OTTOS required minimal training, and scoring required less than 2 min for each patient. The correlation between the scores of experienced occupational therapists was high (.92 for the total scores). The correlation between OTTOS and the other rating instruments ranged from .880 to .340; the highest correlations, as expected, were with test subscales that most closely resembled OTTOS: CONCLUSION: Preliminary data indicated that OTTOS offers a reliable and valid method for rapidly rating the function of patients with psychiatric illness attending task groups. In addition, use of OTTOS improved the communication between occupational therapists and other health care providers, facilitated the education of occupational therapy students, and met the documentation requirements of third-party payers.

Total hip arthroplasty with cement after renal transplantation. Long-term results.

Fifty patients with osteonecrosis following a renal transplantation were managed with a total of seventy-six total hip arthroplasties with cement between 1972 and 1982 at the University of Minnesota. The minimum duration of follow-up was ten years. With use of Kaplan-Meier survivorship analysis, with revision for any reason as the end point, the over-all rate of survival of the implants in all patients was 91 +/- 7 per cent (mean and two standard errors of the mean, 95 per cent confidence interval) at five years and 78 +/- 11 per cent at ten years. The prostheses in the patients who were more than forty years old had a rate of survival of 87 +/- 18 per cent and 72 +/- 30 per cent at five and ten years, respectively, compared with 92 +/- 7 per cent and 80 +/- 12 per cent for the patients who were less than forty years old. The acetabular components had a 94 +/- 6 per cent rate of survival at five years and an 86 +/- 9 per cent rate at ten years. The femoral components had a 97 +/- 4 per cent rate at five years and an 87 +/- 9 per cent rate at ten years. We concluded that the results of total hip arthroplasty with cement after renal transplantation are satisfactory and are comparable with those for patients of similar age who have not had a renal transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Towards an assessment of the influence of climate on wet acidic deposition in Europe.

The EMEP precipitation composition network is used to examine relationships between non-marine SO4(2-), NO3-, NH4+, H+ concentrations and precipitation amount and a local zonal pressure index (an index of the atmospheric circulation). The pattern of the relationships changes across Europe with the zonal pressure gradient explaining more of the variance in ion concentrations in the west, and precipitation amount explaining relatively more of the variance in the east. There is some predictive capability for precipitation composition in the zonal pressure gradient for restricted regions in Europe; R2 values are up to 40% on a daily basis but in some seasons/months attain >60%. The zonal pressure gradient is an index which appears to include pertinent information on transport and wet removal. Preliminary analysis indicates that this approach can be useful in assessing the contributions of changing atmospheric circulation to time-trends of wet acidic deposition in an area stretching from the UK over the North Sea to Denmark. The zonal pressure gradient is known to have varied on time-scales of decades, and the simple index may be one appropriate approach to assessing future deposition patterns from future climate projections.

Catheter with an anchoring tip for chronic joint capsule perfusion.

An orthopedic catheter for long-term access to the synovial joint is anchored by a hollow threaded tap that penetrates the capsule through a hole drilled in the surrounding bone. The proximal end of the catheter is connected to either an implantable drug infusion pump or an implantable access port for continuous or intermittent perfusion or sampling. Four catheters were evaluated in dogs. Three were attached to ports, the fourth to a pump. Water (one trial, 22 weeks) and hyaluronic acid (HA) (5 mg/ml; two trials of 8 weeks each) were administered through ports twice weekly in 1.5 ml boluses; 5 mg/ml HA was delivered by pump (1 trial of 33 weeks) at 0.31 ml/day.

Evaluation of magnetic resonance imaging in the diagnosis of osteonecrosis of the femoral head. Accuracy compared with radiographs, core biopsy, and intraosseous pressure measurements.

The accuracy of magnetic resonance imaging in the detection of osteonecrosis of the femoral head was compared with that of other diagnostic methods in current use: plain radiography, bone-marrow pressure determinations, intramedullary venography, and histological examination of core-biopsy bone specimens. In the first phase of the study, forty-eight patients (ninety-six hips) who were at high risk for avascular necrosis were studied. Abnormal patterns on magnetic resonance imaging, consistent with those seen in necrosis, were found in all hips that were suspected of having Ficat Stage-2 or 3 changes on the basis of radiographic evidence of the disease. Abnormal patterns on magnetic resonance imaging that were characteristic of avascular necrosis were also observed in 17 per cent of the hips that were suspected of having Ficat Stage-0 changes and in 64 per cent of those that showed Stage-1 changes, all with no radiographic changes. In the second phase of the study, twenty-three of the ninety-six hips that were suspected of having early-stage necrosis of the femoral head but showed slight or no radiographic changes were studied by repeat radiographs, Ficat functional evaluations of bone, core biopsies of the femoral head, and magnetic resonance imaging. Of the twenty-three hips, eighteen (78 per cent) had positive changes on magnetic resonance imaging; nineteen (83 per cent) had positive histological evidence of necrosis; and fourteen (61 per cent) had positive findings by bone-marrow pressure studies and intramedullary venography. Although false-negative and false-positive results were observed with magnetic resonance imaging, the over-all results of this study suggest that magnetic resonance imaging may be useful for the early diagnosis of avascular necrosis.

Avascular necrosis in congenital hip dysplasia: the effect of treatment.

Fifty-one patients known to have developed avascular necrosis during treatment for congenital hip dislocations were studied. Thirty-nine patients were followed for a mean of 23 years, 7 months. They were classified as to the severity of involvement, the subsequent treatment provided, and their final result. The greater the involvement, the worse the outcome. Residual subluxation of hips resulted in a poor prognosis. Intervention with open reduction did not result in success. Varus femoral osteotomies and acetabuloplasties met with limited success. Total hip replacements have not resulted in long-term success.

Innominate osteotomy in Perthes disease.

A retrospective study was performed in 27 patients who underwent innominate osteotomy for the treatment of severe Perthes disease. Time intervals between surgery and final follow-up ranged from 5 years to 16 years 4 months. Preoperative and postoperative periods of treatment were often more prolonged than those reported by Salter. One-half of the patients were less than 6 years of age at onset of the disease. A number of patients had significant deformity of the femoral head. Nevertheless, clinically good or fair results were obtained in 88% of the patients and poor results were found in 12%.

Surgical approaches for primary total hip arthroplasty. A prospective comparison of the Marcy modification of the Gibson and Watson-Jones approaches.

Total hip arthroplasty (THA) was performed in 74 consecutive patients alternating the Marcy modification of the Gibson and the Watson-Jones approaches. Comparable series of 37 cases each showed similar operative times, placement of implants, and complications. No particular advantage or disadvantage was observed between these two approaches. Both allow retention of the greater trochanter for primary THA.

Comparison of the transtrochanteric and posterior approaches for total hip replacement.

One-hundred fifty-six consecutive total hip replacements through a lateral transtrochanteric approach were evaluated and compared to a closely matched group of 160 consecutive similar procedures via a posterior approach. The lateral approach did not have any dislocations and created a greater abductor lever arm. However, a 4.5% complication rate was related to the greater trochanter and degraded the result. The posterior approach provided a shorter operative time, required less blood replacement, and resulted in a shorter hospital stay. However a 4.4% incidence of dislocation decreased the rate of recovery and the final result. Since this early experience, an improved technique of reattaching the short external rotators had mitigated the problem of dislocations. Wound and systemic complications, postoperative results, radiographic findings and prosthetic positioning were not significantly different in comparable patients treated by the 2 surgical approaches.

The effect of total hip replacement and general surgery on antithrombin III in relation to venous thrombosis.

This investigation was undertaken to identify and correlate one factor that makes patients undergoing total hip replacement more susceptible to venous thrombosis and pulmonary embolism than those who have almost any other elective orthopaedic procedure, and to determine why the operation of total hip replacement has proved to be relatively resistant to antithrombotic prophylaxis compared with general surgical procedures. Using the depletion of antithrombin III as a marker of activation of the coagulation system, two groups of patients were compared: twenty-one who were subjected to hip arthroplasty and fourteen who underwent general surgical procedures. Both during and after operation the decrease in the quantity of antithrombin III in hip-arthroplasty patients was significantly greater (p less than 0.05) than the decrease in general surgical patients. Seventy-three per cent of hip-replacement patients had venographic evidence of recent thrombosis, 60 per cent of which were discontinuous femoral-vein thrombi. Femoral-vein thrombosis occurs frequently in hip-arthroplasty patients and is relatively resistant to current antithrombotic prophylaxis. The data presented suggest that during hip surgery there is a strong systemic activation of the clotting cascade that is associated with local vessel injury and local stasis in the femoral vein, an association not found in most general surgical procedures.

Mechanical failures in total hip replacement requiring reoperation.

During the years 1971 through mid-1977, approximately 3,000 total hip replacements were performed at The Hospital for Special Surgery using metal-to-plastic prostheses. During that period of time, thirty-five operations were done for mechanical failure in the absence of infection. The mechanical failures were distributed as follows: Fourteen patients had dislocations of the prostheses and seven patients had loosening of the femoral component, mostly with varus positioning of the femoral stem. Six patients, most of them heavy, active men, had fractures of the femoral stem. Three patients had loosening of the acetabular component. (In two of three there was insufficient bone stock over the acetabulum.) Four patients had proximal migration of the greater trochanter and one had a fracture-dislocation of the acetabulum. In all cases a technical or anatomical problem could be identified as the reason for mechanical failure necessitating reoperation. By careful preoperative planning, proper selection of procedures and positioning of prostheses, bone-grafting when necessary, and stricter attention to the technique of using cement, we could conceivably have avoided two-thirds of these failures.

Toxicity of prostaglandins A1 and A2 for cells in culture.

Prostaglandins A1 and A2, in concentrations near 3 x 10(-5) M, produced striking toxicity to muscle, skin and liver cells in culture. Prostaglandins E and F2alpha were much less active in this regard. Toxicity could be measured by reduction in viable cell number, protein and DNA synthesis in the cultures. The sensitivity of cultured cells was related to their age and population density. Dense cultures were sensitive early, in the first 2 days, and resistant after they manifested confluent growth. Sparse cultures remained sensitive later while they continued DNA synthesis and active cell division. It is hypothesized that the prostaglandin A effect is related to active cell division and DNA synthesis.

Effects of indomethacin on acute, subacute, and latent infections in mice and rats.

The comparative effect of indomethacin and hydrocortisone on the resistance of mice or rats to various acute, subacute, and latent bacterial infections was investigated. Large daily doses of indomethacin and hydrocortisone administered to mice challenged with bacterial pathogens, including Klebsiella pneumoniae AD, Salmonella schottmuelleri 3010, Staphylococcus aureus (Smith), Streptococcus pyogenes C203, Salmonella pullorum #2, Proteus vulgaris 1810, and Pseudomonas aeruginosa 2616, revealed that in essentially all of these acute infections, the mortality of the infected mice treated with indomethacin was essentially identical to that found in the infected controls. In contrast, hydrocortisone often lowered the resistance of mice to these acute infections. In a more chronic bacterial infection due to Corynebacterium kutscheri, hydrocortisone produced striking deleterious effects on resistance, whereas indomethacin administration in doses approaching the maximal tolerated level caused no observable adverse effects on host resistance. Indomethacin fed continuously to rats for 80 days, at maximal tolerated levels, caused no observable adverse effects on the host-parasite relationship of rats which were shown to harbor various latent infections. Hydrocortisone administration, however, lowered the resistance of rats as evidenced by increased mortality related directly to extensive bacterial infection. Insofar as infection is concerned, indomethacin behaved like other nonsteroid anti-inflammatory agents such as aspirin and phenylbutazone.