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Biomedical subjects

R Buzzi

Publications and source records attributed to R Buzzi.

At least 37 records · Page 2Linked to original sources
PubMed1991

Autologous bone grafting for medial tibial defects in total knee arthroplasty.

Seventeen posterior stabilized Insall-Burstein knee arthroplasties were implanted in severely deformed varus knees with large medial tibial bony defects. The defect was filled with an autologous bone graft obtained from the same knee and fixed with one or two screws. The patients were reviewed during an average follow-up period of 4 years (range, 2-8 years). The graft was completely united in 14 cases (82%), with bony trabeculae crossing the interface. Fibrous union occurred in three cases (18%). There was no evidence of graft necrosis or collapse. The results were classified as excellent in 10 knees (59%), good in 6 (35%), and poor in 1 (6%), which was revised for femoral loosening. The importance of meticulous technique and correct component positioning is emphasized.

Aged↗
PubMed1991

Reconstruction of the chronically lax anterior cruciate ligament using the middle third of the patellar tendon. A 3-9 year follow-up.

After an average of 5 years, the authors reviewed 76 cases of anterior cruciate ligament reconstruction in which the middle third of the patellar tendon had been used as a free autogenous graft. A lateral Lemaire operation had been used in 85% of the cases and postoperative cast immobilization in 72%. Functional knee instability was eliminated in 96% of the patients. Pain was present at the follow-up in 14.5% of the patients and correlated with both meniscectomy (p = 0.03) and the presence of degenerative changes on the radiographs (p = 0.002). The pivot-shift was eliminated in 93% of the cases and the maximum manual test performed with the KT-1000 arthrometer was less than or equal to 5 mm in 83%. Lateral compartment laxity which was not corrected at operation was frequently associated with graft failure (p = 0.01). Seven patients had difficulty in rehabilitation, and in 6 of these the final result was unsatisfactory. Pain and swelling in the femoropatellar joint were present in 8% of the cases. Slight and moderate degenerative changes were shown on the radiographs in 48% and 10% of the patients, respectively, at follow-up; these findings correlated with meniscectomy (p less than 0.001) and rehabilitation problems (p = 0.03). This procedure achieved lasting, satisfactory results in 70% of the cases. Additional advances include greater care in positioning the graft, use of arthroscopy, and early mobilization. Further studies are needed to verify the advantages of these new techniques.

Adolescent↗
PubMed1991

Quadricepsplasty with the V-Y incision in total knee arthroplasty.

For over 8 years the authors have used the inverted V-Y incision of the quadriceps, a modification of the Coonse and Adams approach, in total knee arthroplasty (TKA) with serious reduction of flexion, ankylosis, or limited mobility of the patella because of previous operations. This procedure not only allows easy and complete exposure, but improves the range of flexion without incision-related complications. Detailed results of a consecutive series of 16 knee arthroplasties are presented.

Aged↗
PubMed1990

Knowledge-based battery design of short-term tests based on dose information.

A construction of batteries of short-term tests (STTs) is described which is based on a classification of 73 chemicals in regard to their carcinogenicity. The 73 chemicals were studied within the U.S. National Toxicology Program (Ashby and Tennant, 1988). The batteries are validated using the classification of 35 additional chemicals. They are defined by logically structured combinations of rules. The single rules are defined by the z-scores of the logarithmic values of the limiting doses obtained from the 4 in vitro STTs used in the study by Ashby and Tennant. The limiting dose is defined as the lowest effective dose or the highest ineffective dose (Waters et al., 1987). The batteries are constructed by minimizing the number of disagreements with the classification by Ashby and Tennant. Compared with the results obtained from single STTs, 2 batteries of 3 STTs have higher concordances with the carcinogenicity data, namely 70% for the NTP data and 74-77% for the independent test data. In addition, a theoretical result shows that the proposed battery design, for a large enough learning set of chemicals, leads to results which are replicated with high probability on a large enough validation set. Based on the first results obtained with a limited number of chemicals it is concluded that the knowledge-based battery design is worth further development.

Animals↗
PubMed1990

Fibrinolytic activity in the synovial membrane of osteoarthritis.

The fibrinolytic activity (FA) has been studied on the synovial membrane obtained from 16 patients with osteoarthritis (OA), 20 patients with rheumatoid arthritis (RA) and 11 control subjects. Todd's autohistographic method, modified by Lotti, was used to investigate the FA and the monoclonal antibodies against u-PA and t-PA were used to identify the main plasminogen activator. Our results show that the FA is increased in the synovial membrane of patients with OA in comparison with the synovial FA of control subjects. In the synovial membranes from patients with RA, the FA shows different results: in some specimens FA is increased, and in others it is diminished or similar, compared with FA of samples from healthy controls. Thus, our data on synovial FA in OA confirm the previous reports, performed in vitro, on the activation of the plasmin system in this degenerative disease. The activity of the fibrinolytic system seems to participate in the cartilage degeneration and, via the activation of collagenase, to perpetuate the cartilage damage.

Adult↗
PubMed1989

Classifications of subjects with the language PROLOG.

The logical language PROLOG is used for the definition and characterization of groups of subjects. The groups are firstly defined by sets of variables with comparable scales. Secondly, the single members of the groups are characterized by logically structured combinations of variables which do not necessarily have comparable scales. The performance of the characterizations is estimated by determining the rates sensitivity and specificity. The new classification method is applied in a follow-up study including the assessment of the activity of 76 healthy subjects during two controlled experiments. The classification with PROLOG is then compared with the methods of logistic regression and with discriminant analysis. The comparisons demonstrate that, under similar conditions, the results of a classification with PROLOG parallel the results of statistically based classification procedures. In addition, PROLOG permits characterizations of single subjects based on variables from different scientific disciplines.

Cardiovascular Physiological Phenomena↗
PubMed1989

Arthroscopic lateral release for patellar pain or instability.

Forty-five arthroscopic lateral releases were reviewed with a follow-up from 2 to 6 years (average 4 years). Satisfactory results were obtained in 60% of the patellar pain group (20 knees) and 68.5% of the instability group (19 knees). The results in osteoarthrosis (6 knees) were unsatisfactory. Postoperative hemarthrosis was infrequent (2.2%). Unfavorable prognostic factors are an incomplete release with an insufficient postoperative passive patellar tilt in the pain group and more than five preoperative dislocations in the instability group. After failure of conservative treatment, a lateral release can be reasonably used in pain syndromes with a tight lateral retinaculum and lateral patellar tracking and in milder cases of instability.

Adult↗
PubMed1989

Arthroplasty for the stiff or ankylosed knee.

Twenty stiff (range of motion, less than 50 degrees) and six ankylosed knees were replaced with the posterior stabilized condylar prosthesis and evaluated after an average of 4.5 years (range, 2.5-7.5 years). There were 81% good to excellent, 11.5% fair, and 7.5% poor results. The maximum overall degree of flexion improved from an average of 60 degrees before surgery to 85 degrees after surgery. Flexion contracture was reduced from 28 degrees to 7 degrees, and the total arc of motion significantly increased from 32 degrees to 78 degrees. Less motion was achieved in the ankylosed knees. A modified inverted V-Y quadricepsplasty was a useful approach to the knee in 11 cases.

Adult↗
PubMed1989

[Aseptic loosening of the Charnley prosthesis].

Out of 100 Charnley prostheses implanted for idiopathic arthrosis and followed up a minimum of 5 years after surgery, 59 were fixed, 24 were characterised by probable radiologic loosening of the femoral component, 13 by probable loosening, and 4 by possible radiologic loosening of the acetabular component. None of the patients was submitted to further surgery. Some of the features of the patients were found to be associated with a higher incidence of femoral loosening. In most of the cases loosening was minimal, only radiologic, and not clinically apparent, and numerous technical improvements in the use of cement and in the design of the prosthesis were introduced subsequent to the period when these patients were operated on.

Adult↗
PubMed1989

[Total hip prosthesis according to Charnley. Review of our cases].

This is a follow-up study of 363 Charnley hip replacements out of 548 implanted from 1970 to June 1984. Clinical results, with a 2-year minimum follow-up (average 5 years, maximum 15 years) are excellent or good in 89.5% of the cases. In the group with minimum 5-year follow-up (average 7, maximum 15 years) the clinical results remain good to excellent in 89.2% of the cases. Radiographic results have been studied in the group with minimum 5-year follow-up. Component stability or radiographic loosening have been studied, taking into account the presence of radiolucent lines between bone and cement, between metal and cement, or based on component migration or positional shift. We have detected radiographic loosening in 11.5% of the acetabular and 13.5% of the femoral components. A correlation was sought between radiographic loosening and some clinical (diagnosis, weight, follow-up period) and radiographic (postoperative component position, polyethylene wear, cement technique, periosteal reaction, myositis ossificans) parameters. There is no strong relationship between radiographic loosening and clinical results, as 28 of 35 radiographically loose prostheses maintained excellent or good results. Finally, the results of a selected group of 29 hips, with a minimum follow-up of 10 years, is reported.

Adult↗
PubMed1989

[Accuracy in high tibial osteotomy in varus gonarthrosis].

We have verified our technical accuracy in a series of 72 high tibial osteotomies for medical gonarthrosis, which were operated following Install's technique. An acceptable alignment (6 degrees-15 degrees valgus) was achieved in 83% of the cases; a loss of correction during the healing phase was detected in 10% of the knees. We have modified some details of the previously employed technique in order to improve accuracy. The leg alignment is determined on 30 x 90 cm standing radiographs, defining the mechanical axes; we aim at 4 degrees of valgus. A guide is employed to determine the width of the wedge of bone to be removed. The osteotomy is fixed by means of two screws and wire; the fixation obtained is stable enough to allow early weigh bearing and range of motion. With these modifications we have been able to improve technical accuracy and we have rendered the postoperative course more acceptable to the patients.

Adult↗
PubMed1989

[Transversal fracture of the patella: experimental evaluation of the Lotke and Ecker method of internal fixation].

Four different methods of internal fixation of transverse fractures of the patella were experimentally evaluated in eight cadaver knees: circumferential wiring, tension band cerclage, cerclage over Kirschner wires and the Lotke's method. Linear and angular displacements were accurately measured by means of a micrometer while actively extending the knee from 90 degrees of flexion to full extension. Circumferential wiring gave the highest displacements, up to 25 mm at 30 degrees of flexion on average. Tension band cerclage showed much better results but the greatest stability was obtained with the cerclage over Kirschner wires and with the Lotke's technique which yielded displacements of less than 1 mm. These last two methods combine the tension band principle and transosseous fixation, which are both essential to obtain a stable fixation.

Evaluation Studies as Topic↗
PubMed1988

Patellofemoral functional results and complications with the posterior stabilized total condylar knee prosthesis.

The authors reviewed 73 knee arthoplasties performed with the Posterior Stabilized Total Condylar prosthesis, with an average follow-up period of 5.5 years. The function of the patellofemoral articulation was specifically analyzed. Patients with documented or suspected tibiofemoral problems were excluded. Using the Hospital for Special Surgery knee rating system, 48 knees (66%) had excellent, 20 had good (27%), and 5 (7%) had fair results. Patients with unilateral disease were able to negotiate stairs and transfer normally in 64% and 100% of the cases, respectively. The most frequent patellofemoral problem was impingement (21%), but reoperation was needed in only one patient. Stress fracture of the patella and subluxation were rare. A medial tilt of the patella on the axial view had no apparent ill effect. The patella was lowered 12 mm on average as a consequence of the standard bone resection sequence and insertion of the tibial component. The patella was significantly lower in patients with impingement than in normal joints. Routine complete patellofemoral resurfacing is advised in total knee joint arthroplasty. Complications are infrequent with appropriate prosthetic design and due technical care.

Adult↗
PubMed1988

Posteriorly stabilised total-condylar knee replacement. Three to eight years' follow-up of 85 knees.

We have reviewed 85 knees in 71 patients after total-condylar posteriorly stabilised (Insall-Burstein) knee replacement with an average follow-up of five years. Excellent or good results were obtained in 90% with an average maximum flexion of 98 degrees. The four poor results (5%) included two with deep infection, one with patellar dislocation and one with loosening. Four other knees (5%) showed signs of probable tibial loosening, but the patients were asymptomatic, the clinical results had not deteriorated with time and lucent lines had not progressed. Varus alignment of the knee and a varus tilt of more than 2 degrees of the tibial component correlated with the incidence of lucent lines around the tibial implant. No patellar stress fractures were seen but impingement symptoms were present in 20%, although they were troublesome in less than half of them. The virtue of the prosthesis lies in its versatility for use in the severely deformed joint.

Adult↗
PubMed1988

High tibial osteotomy in the treatment of arthritic varus knee. A medium term (small) review of 61 cases.

Sixty-one valgizing high tibial osteotomies performed according to the Insall method between 1975 and 1982 were reviewed; follow-up ranged from a minimum of 4 years to a maximum of 11, with an average of 7.5 years. The stage of preoperative osteoarthritis, evaluated according to Ahlbacks's classification, never exceeded Grade 3 (obliteration of the joint space and slight bone erosion). Preoperative varus never exceeded 10 degrees. The clinical results, evaluated on the score-form used at the Hospital for Special Surgery, were satisfactory in 48 cases (79% of the total) and unsatisfactory in 13 (21%). The success rate decreased to 65% in cases with a follow-up exceeding 10 years. There was frequently some loss of radiographic correction between the postoperative and follow-up values, but this was significant in only 9 cases where it exceeded 5 degrees. The arthritis was radiographically progressive in 22 cases, 18 of which were from the satisfactory group (excellent and good) and 4 from the unsatisfactory group (fair and poor). This positive evaluation of the results, even if they tended to deteriorate over a period of time, show that high valgizing tibial osteotomy is an effective operation, particularly when performed in knees without severe deformity.

Adult↗
PubMed1988

An analysis of the survival rate of total-condylar total knee prostheses with posterior stability.

Survival rate tables are an adequate and relatively new means of evaluating prostheses of the knee. These tables may be used to make a clear distinction between success and failure. In a study of 160 prostheses followed-up over a period of 9 years, a Total-Condylar knee prosthesis with posterior stability has a 90% probability of surviving for the entire period, based on mechanical and radiological failures, and a 96% probability based on failures that required its removal. The probability of mechanical or radiological failure is 1% per annum.

Adult↗
PubMed1987

Rapid information processing and concomitant event-related brain potentials in smokers differing in CO absorption.

The present study relates subject-paced rapid information processing to different components of event-related brain potentials in an attempt to gain more information about changes in mental performance in relation to alveolar smoke absorption as assessed by expired air CO measurement. The task consisted in the presentation of pseudorandom sequences of single digits, and the subjects had to respond to each sequence of three odd or three even digits. The triplets evoked a typical late negativity in the event-related potential between the second and third digit as well as a P300 component following the third digit. In 21 smokers, task performance, event-related potentials and tidal air CO concentration were measured before and after smoking a cigarette. The results revealed increases in performance and P300 magnitude from pre- to postsmoking which were unaffected by the amount of CO absorption. A differential trend was seen, however, with the late negativity, which increased from pre- to postsmoking only in subjects with a large amount of CO absorption. The results support the assumption of the distraction arousal model used as an interpretation of these effects on contingent negative variation and suggest that high CO absorbing smokers possibly depend more on neuropharmacological effects of smoking than smokers with a low amount of CO absorption.

Adolescent↗