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Biomedical subjects

R D Scott

Publications and source records attributed to R D Scott.

At least 73 records · Page 4Linked to original sources
PubMed1993

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.

Acetabulum↗
PubMed1993

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.

Adult↗
PubMed1993

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)

Aged↗
PubMed1993

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.

Adolescent↗
PubMed1993

Patellofemoral complications of total knee replacement.

Patellofemoral complications account for the majority of problems following total knee replacement. Many of these problems are technical, and attention to detail at the time of surgery can help avoid them. An understanding of the potential postoperative complications should help one to diagnose these early and prevent catastrophic problems.

Arthritis, Rheumatoid↗
PubMed1991

NMR observation of exchangeable protons of pyridoxal phosphate and histidine residues in cytosolic aspartate aminotransferase.

Observation of the 93-kDa cytosolic aspartate aminotransferase by 500-MHz 1H NMR spectroscopy in H2O has revealed a series of resonances in the 10-18 ppm range arising from exchangeable protons. One of these (peak A) has been assigned to the proton bound to the ring nitrogen of the coenzyme pyridoxal 5'-phosphate. A second (peak B) is assigned to H143 which participates in a chain of hydrogen bonds that includes also the coenzyme-bound proton. There is a mutual nuclear Overhauser effect between these two resonances. Peaks A and B respond to changes in pH and to interaction of the enzyme with coenzyme derivatives and inhibitors. Peak A moves from 15.4 to 17.4 ppm as the pH is lowered, while peak B moves in the opposite direction from 14.7 to 13.7 ppm, both with an apparent pKa of 6.15. This pKa is associated with deprotonation of the imine nitrogen at the Schiff base linkage of the coenzyme with K258 of the enzyme. In spectra of enzyme containing pyridoxamine 5'-phosphate, peak A is observed at 16.5 ppm and peak B is at 13.9 ppm over a broad pH range. Peaks A and B are found at 17.8 and 14.0 ppm, respectively, for the enzyme complex with glutarate. When alpha-methylaspartate is added to the enzyme several new resonances appear in the spectrum, which are attributed to formation of the external aldimine. The position of peak A in spectra of various forms of the enzyme is interpreted to reflect the electronic distribution in the coenzyme ring. Several other peaks in this region of the spectrum also are sensitive to changes in pH or the addition of inhibitors. Some possible assignments of these resonances are discussed.

Aspartate Aminotransferases↗
PubMed1991

NMR spectra of exchangeable protons of pyridoxal phosphate-dependent enzymes.

We have recorded 1H NMR spectra in H2O for exchangeable protons of four pyridoxal phosphate-dependent enzymes: D-serine dehydratase, aspartate aminotransferase, tryptophan: indole-lyase and glutamate decarboxylase. The molecular masses range from 48-250 kDa. In every case there are downfield peaks which are lost when the apoenzyme is formed. In most cases some peaks shift in response to interactions with substrates and inhibitors and with changes in pH. We associate one downfield resonance with the proton on the ring nitrogen of the coenzyme and others with imidazole groups that interact with coenzyme or substrates. The chemical shift for the coenzyme-bound proton differs for free enzyme, substrate Schiff base or quinonoid forms.

Animals↗
PubMed1991

The accuracy of tibial intramedullary alignment devices in total knee arthroplasty.

The accuracy of a tibial medullary alignment device is assessed radiographically in 30 varus and 30 valgus knees undergoing total knee arthroplasty. The results suggest that although the device is reliable and accurate for varus knees, it may lead to malalignment of up to 5 degrees in valgus knees. Overall neutral alignment was achieved in 83% of the varus knees and 37% of the valgus knees. Tibial bowing was the main source of error and was present in 66% of the valgus knees, with mean of 3 degrees. Preoperative long films or cross-checking with external alignment devices is recommended to assure neutral alignment in genu valgus deformity.

Congenital Abnormalities↗
PubMed1991

Capsular impingement as a source of pain following bipolar hip arthroplasty.

Concerns regarding the extent and predictability of pain relief with bipolar hemiarthroplasty have been raised. Inconsistent clinical results have been reported, with persistent postoperative groin pain noted in some patients. A diverse number of bipolar operative techniques have been reported, but discussion of the surgical treatment of capsular tissue has usually been omitted. Although the source of postoperative pain is difficult to determine, the authors report the relief of groin pain after a capsulectomy in a patient with a preexisting bipolar hemiarthroplasty, thus offering one possible etiology.

Adult↗
PubMed1991

Radiographic detection of metal-induced synovitis as a complication of arthroplasty of the knee.

Radiographs of eighteen patients who had had a diagnosis of metal-induced synovitis subsequent to a knee-replacement arthroplasty were retrospectively reviewed. The presence of a dense line outlining a portion of the capsule or articular surface of the knee joint (the so-called metal-line sign) was noted in association with wear in eleven patients. In the nine patients who had a positive sign and also had specimens available for histological examination, there was dense deposition of metal particles, whereas in the six patients who did not have a metal-line sign and had specimens available for histological examination, five had only a slight amount of metal in the synovial tissue and one, a moderate amount. The presence of the metal-line sign was associated with metal-induced synovitis in eleven of the eighteen patients. The sign should be useful in helping to make this diagnosis preoperatively in many patients.

Chromium Alloys↗
PubMed1991

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.

Aged↗
PubMed1991

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)

Aged↗
PubMed1990

Total shoulder arthroplasty versus hemiarthroplasty. Indications for glenoid resurfacing.

The results of total shoulder arthroplasty and hemiarthroplasty in a similar patient population were compared in an effort to define more clearly the indications for resurfacing the glenoid. The results of 64 Neer hemiarthroplasties in 59 patients were compared with 146 Neer total shoulder arthroplasties in 134 patients in a retrospective review of the period between 1974 and 1986. The average follow-up period was 44 months (range, 24-124 months). Hemiarthroplasty and total shoulder arthroplasty produced similar results in terms of functional improvement. Pain relief, range of motion, and patient satisfaction were better with total shoulder arthroplasty than hemiarthroplasty in the rheumatoid population. Progressive glenoid loosening was found in 12% of total should arthroplasties but no correlation with pain relief or range of motion was noted. Total shoulder arthroplasty is recommended for patients with inflammatory arthropathies, and hemiarthroplasty is recommended for patients with osteoarthritis, avascular necrosis, and four-part fractures with preservation of glenoid congruity and absent synovitis.

Adult↗
PubMed1990

Total hip and knee arthroplasty in juvenile rheumatoid arthritis.

Total hip or knee arthroplasty is indicated in patients with juvenile rheumatoid arthritis when there is marked functional impairment and/or severe disabling pain from advanced structural hip or knee joint involvement. Relief of pain and dramatic improvement in function can be achieved in most patients. When both the hip and knee are involved, hip arthroplasty should probably be done first. Regional anesthesia is preferable. Careful preoperative planning is essential because custom prostheses are often required. Small bone size, osteoporosis, and soft-tissue contractures make the surgery technically demanding. Skeletal immaturity is not an absolute contraindication to surgery. Component loosening is the most frequent late complication in hip arthroplasty. It is less common in condylar metal-to-plastic knee arthroplasty in which patellar complications predominate. Cementless arthroplasty has an evolving role in the patient with juvenile rheumatoid arthritis and, to date, is more often used in the hip than in the knee.

Arthritis, Juvenile↗
PubMed1990

Bone loss in the distal anterior femur after total knee arthroplasty.

Bone loss in the distal anterior femur in asymptomatic total knee arthroplasty (TKA) patients has been noted roentgenographically and during revision surgery. A retrospective roentgenographic review of 147 TKA cases was carried out to document bone loss. The influence that the mode of fixation (porous coated and cemented) and the implant design have on bone loss was examined. The time of onset and the progression of bone loss were studied. Bone loss occurred in the distal anterior femur in the majority of cases reviewed (68%). The prevalence of bone loss was independent of the mode of fixation and the implant design. By qualitative observation, roentgenographically detectable bone loss occurred within the first postoperative year and did not progress further. Previously three-dimensional finite element analysis demonstrated that the replacement of the bearing surface of the femur with a stiff metallic implant reduces the stress in the distal anterior femur by at least one order of magnitude. It is therefore speculated that the observed bone loss results from stress shielding. The apparent lack of progression may reflect the development of a new remodeling equilibrium under the altered stress conditions. The bone loss in the distal anterior femur described has not been implicated as a source of failure. However, since the bone strength in the femoral region is compromised as it becomes osteopenic, bone failure may occur with longer periods of cyclic loading. Furthermore, as a result of bone loss, revision arthroplasty may be more difficult.

Aged↗
PubMed1990

Two- to four-year results of posterior cruciate-sparing condylar total knee arthroplasty with an uncemented femoral component.

One hundred fourteen hybrid Press-Fit Condylar total knee arthroplasties (TKAs) were reviewed an average of 2.8 years after surgery to determine if this method of implantation provided satisfactory results compared with conventional cemented TKAs. Ninety-three percent of the knees had good or excellent results, and 94% of the knees had at most only mild or occasional pain. One knee with a metal-backed patella was revised for mechanical failure of the patellar button. Roentgenographic analysis of the femoral component interface showed that 30% of knees had a radiolucent line in at least one zone. However, none of the lines was wider than 1 mm, and none was about the central stem. There were no signs of loosening about any of the components. It was concluded that hybrid TKA provides a good and predictable result that is comparable to cemented TKA.

Adult↗
PubMed1990

Reconstruction of the deficient acetabulum using the bipolar socket.

Although originally conceived as part of a two-stage procedure for the reconstruction of the deficient acetabulum, the use of a bipolar/grafting technique in selected patients can provide acceptable results as a definitive procedure. Critical technical considerations include proper preparation and grafting of the acetabular bed and careful sizing of the outer bipolar shell. Acceptable levels of pain relief and functional gain were obtained in 47 cases, with a follow-up mean Harris hip score of 86. Despite some initial socket migration in all hips, roentgenographic stability was gained after the first year. One acetabular failure was related to graft placement in the superolateral position. Bipolar reconstruction is indicated for contained acetabular defects only. In addition, the surgeon must have access to a complete inventory of socket sizes to ensure a proper fit and a bone bank to obtain adequate amounts of allogeneic bone.

Acetabulum↗