Posterior cruciate supplementing total knee replacement using conforming inserts and cruciate recession. Effect on range of motion and radiolucent lines

This study was performed to determine if a sagittally curved conforming tibial insert can be used with a retained, but balanced, posterior cruciate ligament without deleterious effects on range of motion (ROM) and tibial radiolucencies, as compared with a flatter insert that is less conforming and does not require cruciate balancing. The authors reviewed 50 consecutive primary knees implanted with flatter posterior lipped inserts and 50 consecutive primary knees with curved inserts and posterior cruciate ligament balancing. The average ROM for both groups was the same postoperatively as preoperatively: 111 degrees for the posterior lipped inserts and 113 degrees for the curved inserts. The incidence of tibial radiolucent lines was 8% for both groups. The authors conclude that sagittally curved, more conforming tibial inserts with retained, but balanced, posterior cruciate ligaments, do not adversely effect ROM and tibial radiolucencies. Their use forms an attractive compromise between the schools of cruciate preservation and cruciate substitution, maximizing their advantages while minimizing their disadvantages. Functional ROM can be achieved while bone stock is preserved, the joint line is restored, and wear characteristics are improved.

NMR studies of 1H resonances in the 10-18-ppm range for cytosolic aspartate aminotransferase

Continuing a previous investigation (Kintanar, A., Metzler, C. M., Metzler, D. E., and Scott, R. D. (1991) J. Biol. Chem. 266, 17222-17229), we have recorded 1H NMR spectra at 500 MHz in the 10-18-ppm range for the 93-kDa porcine cytosolic aspartate aminotransferase and for four specific mutant forms of the enzyme in which histidine 68 has been replaced by lysine or histidine 143, 189, or 193 has been replaced by glutamine. We have correlated resonances for apoenzyme, pyridoxamine and pyridoxal phosphate forms, and dicarboxylate complexes and have assigned imidazole NH resonances of active site histidines. The chemical shifts of several resonances undergo pH-dependent changes around the pKa of the Schiff base proton at the active site. Other resonances shift upon binding of dicarboxylates or other ligands. Phosphate or carboxylate ions, which can also occupy the site of the substrate's alpha-carboxylate, cause rapid exchange of the Schiff base proton. Although most resonances in the 10-18-ppm range disappear rapidly in D2O, a few are retained for months in the presence of the dicarboxylate inhibitor glutarate. We demonstrate that changes in chemical shifts and in exchange rates are sensitive indicators of electronic interactions of the enzyme with ligands and of conformational change. Nuclear Overhauser effects from NH protons have allowed us to identify resonances of CH protons of the imidazole rings of histidines 143, 189, and 193. Observed and predicted chemical shifts have been compared. We conclude that the net charge on this histidine cluster is zero but that some negative charge from the aspartate 222 carboxylate is donated inductively into the histidine 143 ring. Studies of the related enzyme from Escherichia coli are provided in an accompanying paper (Metzler, D. E., Metzler, C. M., Scott, R. D., Mollova, E. T., Kagamiyama, H., Yano, T., Kuramitsu, S., Hayashi, H., Hirotsu, K., and Miyahara, I. (1994) J. Biol. Chem. 269, 28027-28033). Our approach should be applicable to the study of active sites of a broad range of relatively large proteins.

NMR studies of 1H resonances in the 10-18-ppm range for aspartate aminotransferase from Escherichia coli

We have recorded 500-MHz 1H NMR spectra in the 10-18-ppm range for aspartate aminotransferase from Escherichia coli and for three specific mutant forms. Histidine 143 has been replaced by either alanine or asparagine. In the third mutant, tryptophan 140 has been replaced by phenylalanine. The NMR spectrum of the native enzyme is very similar to that of porcine cytosolic aspartate aminotransferase in the most downfield region. However, the resonances of the proton on the ring nitrogen of the pyridoxal 5'-phosphate (peak A) and on the His-143 imidazole ring (peak B) of the E. coli enzyme are broader and more readily lost at low pH or higher temperatures than those of the porcine enzyme. The possible role of tautomerism in promoting such broadening is discussed. In the histidine mutant proteins, peak A of the pyridoxal 5'-phosphate form is too broad to see under most conditions but is clearly present in the pyridoxamine phosphate form. Peak B is missing in the 2 histidine mutants. Observation of nuclear Overhauser effects further confirms the identity of B as the resonance of HN epsilon 2 of His-143 and that of peak D at approximately 11.8 ppm as HN epsilon 2 of His-189. The mutant spectra also provide insight into electronic interactions between groups in and near the active site which confirm and supplement conclusions drawn from spectra of porcine cAspAT. While no clear loss of a peak was observed for the Trp-140 mutant in its free form, the spectrum of the succinate complex lacked a strong band at 11.26 ppm. This may represent the Trp-140 indole NH proton which has been shifted downfield by binding to a succinate carboxylate group. While our results confirm the basic similarity of cytosolic aspartate aminotransferase and E. coli aspartate aminotransferase 1H NMR spectra, they also point out differences that may be useful in identifying resonances. A large number of mutant proteins have been prepared for the E. coli enzyme. The present results provide essential information for future study of these mutants and for study of NMR spectra of isotopically labeled enzyme.

Catastrophic failure of the polyethylene liner of uncemented acetabular components

Ten cases are described of catastrophic failure of the polyethylene liner of three different designs of uncemented acetabular component. Failure occurred as a result of either 'wearthrough' to the metal backing, liner fracture or a combination of both, at a mean of 4.6 years after implantation (2 to 7.6). At revision there was metallosis in all hips and osteolysis of the femur or the pelvis in six. Catastrophic failure was seen only in cups with a minimum polyethylene thickness of less than 5 mm.

NMR spectroscopy of exchangeable protons of glucoamylase and of complexes with inhibitors in the 9-15-ppm range

1H-NMR spectra have been recorded for glucoamylases I and II from Aspergillus awamori var. X100 and from A. niger in the 9-15-ppm region. At least 17 distinct peaks, many of them arising from single protons, are observed. These are designated A-Q, A being the furthest downfield. At least 9 of these are lost rapidly by exchange when the enzyme is placed in D2O. Peaks A, B, E and H undergo distinct shifts with pH change in the pH region 3-7. Several others undergo smaller shifts. Small differences are also seen between the enzymes from the two different sources. Binding of the pseudotetrasaccharide inhibitor acarbose leads to a 0.50-ppm downfield shift of peak B, other smaller changes, and retention of two additional protons in D2O. delta-D-gluconolactone induces shifts in peaks E, H, and L. The slow substrate maltitol causes peak A to broaden and shift, peaks J and K to shift and a new or greatly shifted resonance to appear at 15.4 ppm. It disappears as the maltitol is hydrolyzed. Treatment with iodoacetamide or diethyl pyrocarbonate leads to disappearance of peak D at 12.3 ppm. When this peak was irradiated strong nuclear Overhauser effects (NOE) were observed at 8.01 ppm and 7.22 ppm, positions expected for the C epsilon 1 and C delta 2 protons of an uncharged imidazole ring. We identify D as arising from the N epsilon 2 proton of His254 which is uncharged except at the lowest pH values. Other NOE and two-dimensional NOE spectra have provided additional information. Three mutant forms of the A. niger enzyme, in which tryptophan residues have been replaced by phenylalanine, have been examined. Because of shifts induced by changes in ring current and other environmental effects it is hard to make a direct identification of the resonances from the replaced indole NH protons. However, on the basis of a distinct NOE between peaks E and H we have identified these resonances as arising from the indole NH protons of Trp52 and Trp120. Other possible assignments are considered. The NMR spectra of the glucoamylases I, which have a starch binding domain of about 104 residues at the carboxyl terminus, show four sharp resonances in the 9.7-10.6-ppm range that are not present in the glucoamylases II, which lack this domain. These resonances no doubt represent the four indole NH ring protons from Trp543, Trp562, Trp590 and Trp615. Three of these are very sharp suggesting a high mobility of this domain.

Catastrophic failure of the polyethylene liner of uncemented acetabular components

Ten cases are described of catastrophic failure of the polyethylene liner of three different designs of uncemented acetabular component. Failure occurred as a result of either 'wearthrough' to the metal backing, liner fracture or a combination of both, at a mean of 4.6 years after implantation (2 to 7.6). At revision there was metallosis in all hips and osteolysis of the femur or the pelvis in six. Catastrophic failure was seen only in cups with a minimum polyethylene thickness of less than 5 mm.

Bipolar revisions with bone-grafting for cavitary and segmental acetabular defects. A minimum 5-year follow-up study

Bipolar revisions used in massive uncontained acetabular defects often lead to high migration rates and early clinical failure. Reconstructions for less severe acetabular bone deficiencies were studied radiographically and clinically. Thirty-two bipolar revisions with bone-grafting were performed for cavitary and segmental acetabular defects. The average follow-up period was 6 years (range, 5-8.4 years). Medial migration averaged 2.3 mm (range, 0-7 mm), oblique migration averaged 2.9 mm (range, 0-8 mm), and superior migration averaged 5.9 mm (range, 0-15 mm). Continued migration at the final follow-up evaluation was noted in all but nine hips. Arrested migration was observed when cavitary defects were encountered. Segmental medial wall defects resulted in increased medial migration. Segmental superior rim defects resulted in large amounts of superior migration. Preoperative Harris hip scores averaged 47 before surgery and 86 at the final follow-up evaluation. Postoperative clinical scores did not deteriorate with radiographic evidence of progressive migration. Six reoperations for femoral complications of fracture or loosening were performed at an average of 4.7 years with concomitant conversion of the bipolar prosthesis to a fixed cementless cup. One re-revision was performed for acetabular disassembly at 6.6 years. When cavitary defects exist, allografting with a bipolar endoprosthesis can provide durable reconstructions with excellent clinical function. Bipolar revisions are also a relatively simple means of providing stability in recurrent dislocation cases.

Role of apical and basolateral secretion in turnover of glutathione in LLC-PK1 cells

Previous clearance measurements have established that the rapid turnover of renal proximal tubular glutathione is in part due to apical secretion and degradation by gamma-glutamyltranspeptidase, an ectoenzyme that is primarily associated with the brush-border membrane. The relationship between glutathione turnover and secretion was further characterized using confluent cultures of LLC-PK1 cells grown on nitrocellulose supports. The resulting cell layer was impermeable to [3H]inulin and exhibited a polarized expression of gamma-glutamyltranspeptidase. Incubating cells with 5 mM buthionine sulfoximine, an inhibitor of glutathione synthesis, produced an 86% inhibition of [35S]cystine incorporation into intracellular glutathione. Under these conditions, the prominent intracellular pool of glutathione turns over with an apparent half-life of 4 h and a first-order rate constant of 0.17 h-1. This turnover is unaffected by pretreatment with AT-125, an inhibitor of gamma-glutamyltranspeptidase. The rate of accumulation of glutathione in the apical and basolateral medium of cells pretreated with AT-125 was 22 and 34 nmol.mg protein-1.h-1, respectively. The combined secretion was equivalent to the calculated turnover rate of intracellular glutathione (57 nmol.mg protein-1.h-1). Therefore, the combined processes of apical and basolateral secretion can account for the turnover of intracellular glutathione in LLC-PK1 cells.

Sellafield waste radionuclides in Irish sea intertidal and salt marsh sediments

Low level liquid radioactive waste discharges from the Sellafield nuclear fuel reprocessing plant in north west England had generated environmental inventories of about 3 × 10(16) Bq of(137)Cs, 6.8 × 10(14) Bq of(239,240)Pu and 8.9 × 10(14) Bq of(241)Am by 1990. Most of the(239,240)Pu and(241)Am and about 10% of the(137)Cs has been retained in a deposit of fine marine sediment close to the discharge point. The quantities of radionuclides discharged annually from Sellafield decreased by two orders of magnitude from the mid-1970s to 1990 but estimated critical group internal and external exposure decreased by less than one order of magnitude over this period. This indicates that during the period of reduced discharges, radionuclides already in the environment from previous releases continued to contribute to the critical group exposure and highlights the need to understand processes controlling the environmental distribution of the radionuclides.Redistribution of the contaminated marine sediment is potentially of major significance in this context, in particular if it results in transport of radionuclides to intertidal areas, where contact with the human population is relatively likely.A review is presented of published work relating to Sellafield waste radionuclides in Irish Sea sediments. Data on temporal and spatial trends in radionuclide concentrations and activity ratios are collated from a number of sources to show that the dominant mechanism of radionuclide supply to intertidal areas is by redistribution of the contaminated marine sediment. The implications of this mechanism of supply for trends in critical group radiation exposure are considered.

Depression among female registered nurses

Depression, the most frequently diagnosed psychiatric illness, is characterized by feelings of sadness, pessimism, self-dislike and loss of energy, motivation and concentration. The relationship of self-esteem, assertiveness and anxiety to depression is studied in a group of female nurses. Recognizing predisposing factors in this high-risk group can begin a process to treat this illness.

Bipolar socket in protrusio acetabuli. 3-6-year study

Twenty-two hips with protrusio acetabular deformity in 14 patients received bipolar socket hemiarthroplasty combined with bone-grafting to the medial wall defect. The surgical technique included crushed cancellous grafting and attention to adequate rim contact for the socket. Results were evaluated at a mean of 54 months after surgery (range, 36-76 months). On hip had thigh pain attributable to a loose femoral component. No patient had groin pain at follow-up examination. A satisfactory range of motion was achieved in all but one case, and an average increase of 40 points in the Harris hip score was realized. Radiographically, all acetabuli were returned to a more normal, inferolateral position. Socket migration (measured relative to the teardrop) in the range of 3-7 mm was noted in 5 hips; the remaining 17 hips displayed no or minimal migration of the socket (< 3 mm). The bipolar socket with crushed cancellous graft appears to be an acceptable surgical alternative in protrusio acetabuli, providing a reliable relief of pain, satisfactory functional results, and a restoration of acetabular bone stock in the majority of cases.

Posterior polyethylene wear in posterior cruciate ligament-retaining total knee arthroplasty. A case study

Controversy over whether to retain the posterior cruciate ligament (PCL) during primary total knee arthroplasty continues. Both the retaining and substituting designs have their respective advantages and disadvantages. In order to capitalize on the advantages of the PCL retaining design, precise techniques in ligament balancing are required. An incorrectly tensioned PCL--too tight or too loose--may exaggerate the disadvantages of the retaining design and lead to early catastrophic failure. Three cases of early catastrophic posterior wear are presented. Although no definite documentation of excessive PCL tension is available, the authors feel that this may have had a significant role in the etiology of this wear pattern. Possible causes of incorrect PCL tension as well as intraoperative techniques to balance the PCL properly are discussed.

The importance of the role of the patient in the outcome of schizophrenia

The Family Interpersonal Perception Test (FIPT) was used to explore the relationships between schizophrenic patients and their parents, and how these related both to relapse in the year after discharge and to improvement in social functioning. Forty schizophrenic patients and their parents were tested during their first ever admission to hospital and again two years later. Parents' and patient's views of each other were more negative in those with worse outcome, but what most significantly distinguished groups with different outcomes was how patients expected their parents to see them. The FIPT, therefore, reveals patterns of interaction in which the patient's role in outcome is at least as important as that of the parents, and can aid the identification of specific features with which to work in therapy.

Acetabular revision with the bipolar prosthesis and particulate bone grafting

Acetabular revisions with bipolar prostheses and particulate bone grafting are seldom performed because of the clinical success of porous coated cementless acetabular components. When limited to cavitary defects and appropriate-sized implants, durable reconstructions with excellent clinical function can be achieved with bipolar revisions. Recalcitrant instability of total hip arthroplasty remains an indication for bipolar revisions.

Capitellocondylar total elbow replacement in rheumatoid arthritis. Long-term results

We evaluated the long-term results of 202 capitellocondylar total elbow replacements that had been performed, from July 1974 through June 1987, in 172 patients. The duration of follow-up averaged sixty-nine months (range, twenty-four to 178 months). At the most recent follow-up examination, use of a 100-point rating score demonstrated an improvement from an average preoperative score of 26 points (range, 2 to 50 points) to an average postoperative score of 91 points (range, 45 to 100 points). The most improvement occurred in the categories of relief of pain, functional status, and range of motion in all planes except extension. The improvements in these categories and in the roentgenographic appearance that were seen in the early postoperative period did not deteriorate with time. The average preoperative arc of motion at the elbow ranged from -37 degrees of extension to 118 degrees of flexion. The average postoperative arc of motion at the elbow ranged from -30 degrees of extension to 135 degrees of flexion. Supination improved from 45 degrees preoperatively to 64 degrees postoperatively; pronation improved from 56 degrees preoperatively to 72 degrees postoperatively. The roentgenograms showed a radiolucent line adjacent to eight humeral and nineteen ulnar components; most of the lines were incomplete and one millimeter wide or less. Revision of the prosthesis was necessary in three elbows (1.5 per cent) because of loosening without infection, and in three additional elbows because of dislocation of the prosthesis. Complications included deep infection in three elbows (1.5 per cent); problems related to the wound in fifteen (7 per cent); permanent, partial sensory ulnar-nerve palsy in five (2.5 per cent); permanent, partial motor ulnar-nerve palsy in one (0.5 per cent); and dislocation in seven (3.5 per cent).

Cementless total knee arthroplasty in juvenile onset rheumatoid arthritis

Twenty-two total knee arthroplasties with at least one cementless component were performed in 14 patients with juvenile rheumatoid arthritis (JRA) from 1985 to 1989. All 22 femoral components and ten tibial components were implanted cementless. The mean age at operation was 26 years. All 14 patients were available for follow-up evaluation at an average of 3.9 years (range, two to 6.2 years). Using The Knee Society's scoring system, the knee score improved from an average of 18 points (range, 0-47 points) preoperatively to 92 points (range, 58-100 points) at follow-up evaluation. The functional score improved from 28 points (range, 0-55 points) to 76 points (range, 40-100 points). Nonprogressive radiolucencies of less than 1 mm were observed in two knees. One reoperation was performed for failure of a metal-backed patellar component. Knee arthroplasty with cementless components in selected JRA patients can give results comparable with a fully cemented knee at the two- to six-year follow-up evaluation.

Can islet cell antibodies predict IDDM in the general population?

OBJECTIVE

To evaluate the likely prognostic significance of ICAs in children with no family history of IDDM.

RESEARCH DESIGN AND METHODS

We examined the prevalence of ICAs in 2925 English schoolchildren aged 9-13 yr and in 274 age-matched siblings of children with diabetes from the same region, and we compared the estimated risk of progression to diabetes within 10 yr in the two groups.

RESULTS

ICAs were present at levels > or = 4 JDF U in 2.8% of schoolchildren and 6.6% of siblings and at > or = 20 JDF U in 0.8% of schoolchildren and 2.2% of siblings. Although ICAs are only 2-3 times more prevalent in siblings than schoolchildren, the estimated cumulative risk that siblings will progress to diabetes by age 21 is 13 times greater (2.8 vs. 0.21%).

CONCLUSIONS

ICAs are unexpectedly prevalent in English schoolchildren, but only a small minority, with this evidence of immune activation directed against islet cells, will progress to diabetes. Although ICAs alone have limited predictive value in the general population, combining two or more predictive tests in series could achieve a level of prediction equivalent to that now obtained in first-degree relatives.

Total knee arthroplasty without patellar resurfacing. Clinical outcomes and long-term follow-up evaluation

Total knee arthroplasty (TKA) without resurfacing of the patella by a single surgeon was reviewed retrospectively in 125 patients: 66 patients (79 knees) were included in the final study group, 32 patients were deceased, 13 were without current address and not able to be contacted, and 14 patients were unable to complete a questionnaire because of severe illness or language barrier. All patients had a diagnosis of osteoarthrosis. The decision to leave the patella unresurfaced was based on the presence of satisfactory patellar articular cartilage, absence of eburnated bone, congruent patellofemoral tracking, normal anatomic patellar shape, and no evidence of crystalline disease or an inflammatory synovitis. A lateral retinacular release was performed in 13 knees (16.5%) to facilitate congruent patellar tracking. The follow-up period averaged 7.5 years (range, 2.4-15.5 years). There were no component revisions and no reoperations. The mean Knee Society score improved from 23.2 to 89.9 postoperatively and the function score improved from 58.4 to 92.0 postoperatively. Mild anterior knee pain was reported in 19%. Satisfaction with the surgical result was expressed in 89.5% of patients; 4% were somewhat satisfied; 2.6% were somewhat dissatisfied; and 4% were neutral. Of the patients who had mixed bilateral TKA (one TKA with unresurfaced patella, the other resurfaced), 46% rated both as equal; 46% preferred the TKA with the resurfaced patella; and 7.7% preferred the unresurfaced patella. In patients meeting the selection criteria outlined above, TKA without resurfacing of the patella provided satisfactory long-term results and a high degree of patient satisfaction with an absence of mechanical complications and no reoperations at the average 7.5-year follow-up evaluation.(ABSTRACT TRUNCATED AT 250 WORDS)

Unicompartmental versus total knee arthroplasty in the same patient. A comparative study

The purpose of this study was to compare unicompartmental knee arthroplasty (UKA) with total knee arthroplasty (TKA) and more specifically to evaluate the role of the patella in patient preference between UKA and TKA. A group of 23 patients were chosen, each with a UKA in one knee and a TKA in the opposite knee. As a subset of the group, 13 patients were compared who had not had patellar resurfacing on their TKA side (Group A) versus ten patients who had patellar resurfacing (Group B). Each patient had a UKA and TKA performed during the same hospitalization. Each patient's resurfacing was performed by the same surgical team. Moreover, inpatient care and physical therapy for each patient's respective UKA and TKA were the same. Patient evaluation consisted of chart review, joint registry data, and telephone interviews that focused on patient preference regarding pain, stability, "feel," and ability to climb stairs. The 23 patients studied had an average follow-up period of 81 months (range, 38-153 months). There were 14 men and ten women with an average age of 67 years. Preoperative diagnosis was osteoarthritis in 22 patients and rheumatoid arthritis in one patient. Range of motion (ROM) improved from a preoperative mean of 106 degrees to 123 degrees postoperatively on the UKA side. Mean ROM for the Group A TKAs improved from 104 degrees to 109 degrees, whereas the Group B TKAs remained unchanged at 113 degrees. For patients surveyed in Group A, 31% stated that their UKA knee was their better knee overall, 15% stated that their TKA knee was their better knee overall, and 54% could find no difference.(ABSTRACT TRUNCATED AT 250 WORDS)

Unicompartmental knee arthroplasty. Eight- to 12-year follow-up evaluation with survivorship analysis

One hundred consecutive unicondylar knee arthroplasties were reviewed after eight to 12 years of follow-up evaluation. Eighteen patients (19 knees) had died, four patients (four knees) were lost to follow-up evaluation, and 13 patients (13 knees) had revision. Survivorship analysis revealed 90% survivorship of the prostheses at nine years, 85% at ten years, and 82% at 11 years. Sixty-four knees in 51 patients were studied clinically and roentgenographically at final follow-up study. Of these, 87% had no significant pain. The average knee flexion was 115 degrees. Anatomic knee alignment averaged 3 degrees of valgus for the knees with preoperative varus alignment and 8 degrees of valgus for knees with preoperative valgus alignment. Fifteen percent of these elderly patients (mean age, 80 years) used a cane outdoors, but only 8% because of their knee. Sixty percent had radiolucent lines at the tibial bone-cement interface, and these lines were incomplete in 96% of cases.