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L Munuera

Publications and source records attributed to L Munuera.

49 records · Page 3Linked to original sources
PubMed1992

Scintimetric study of the bone response around noncemented knee prosthesis. Preliminary results.

The bone response to a noncemented knee prosthesis was observed by quantified isotopic gammagraphy. One hundred six sequential scintimetric explorations were performed in 36 patients with total knee arthroplasty. Fifteen areas of interest were taken into consideration and their gammagraphic analyses were compared with radiologic findings during a postsurgery period of 24 months. Starting with a very high radionuclide uptake level obtained in the first postsurgery level, a gradual decrease was correlated with osteoblastic activity. In this first evaluation, the gammagraphic response around the implant is different in biologic prostheses than in cemented ones. These data may be useful for evaluating implants in orthopedic surgery.

Female↗
PubMed1992

Early and late loosening of the acetabular cup after low-friction arthroplasty.

Between 1971 and 1979, 680 low-friction arthroplasties of the hip were performed in 598 patients. The average duration of follow-up was twelve years and eight months. Sixty-one acetabular cups had loosening as seen on roentgenograms eighteen years postoperatively, resulting in a total cumulative probability of loosening of 19 per cent, according to survivorship analysis. In twenty-nine cups, the loosening appeared within ten years after the operation (early loosening) and in thirty-two, more than ten years after the operation (late loosening). Early loosening was associated with deficient structure of the bone of the acetabulum, a previous congenital dislocation of the hip, acetabular fracture, or acetabular protrusion in all instances (p < 0.01). Late loosening was associated with the depth of acetabular wear. Of the thirty-two cups that had more than two millimeters of wear, eighteen (56 per cent) had loosening on the roentgenograms (p < 0.001). In hips that had early loosening, migration was the most frequent finding, and its rate of progression was higher than in hips that had late loosening (p < 0.001). In late loosening, a complete bone-cement radiolucency of more than two millimeters was the most frequent finding. Clinical failure was seen in twenty-two (76 per cent) of the twenty-nine cups that loosened early and in nine (28 per cent) of the thirty-two cups that loosened late. The probability of extensive resorption of bone necessitates close observation of patients who have early loosening, while a reasonable period of observation is possible for those who have late loosening.

Acetabulum↗
PubMed1992

The femoral component in low-friction arthroplasty after ten years.

In 623 low-friction arthroplasties ten years after implantation, 70 hips (18.04% after 16 years) showed loosening of the femoral component. Eighty-four percent appeared within ten years. Fracture of the stem occurred in 4.3% of cases after 16 years, and resorption over 5 mm of the femoral neck occurred in 9.3%. Calcar cysts appeared in 2.9% and endosteal cavitations in 18.04% after 16 years; both findings were related to acetabular wear greater than 2 mm. Gruen's Type III (calcar pivot) was the least common loosening (6.8%) during the first ten years. After this time its incidence increased to 17.1%. Loosening of the femoral component was not related to age, weight, or activity. It was, however, associated with poor surgical technique, i.e., varus position (46%), cementation defects (34%), and/or femoral neck osteotomy on the lesser trochanter (36%).

Adolescent↗
PubMed1991

Degenerative lesions in the articular cartilage after meniscectomy: preliminary experimental study in dogs.

Articular cartilage degeneration was studied in an experimental model including 68 knees of adult dogs on which five different types of medial meniscectomy had been performed with a followup period of 10 to 450 days. The results were assessed by macroscopic, radiologic, and histologic methods. The degenerative lesions increased proportionally to the amount of meniscal tissue resected and the duration of observation. These lesions proved to be more intense at the tibial plateau compared to the femoral condyle. For both joint surfaces the predominant location was the central zone. Considering the degenerative process by the articular cartilage after total meniscectomy, maximum preservation of meniscal tissue is recommended.

Animals↗
PubMed1990

Meniscal repair following meniscectomy: mechanism and protective effect. Experimental study in the dog.

Meniscal repair was studied to evaluate the mechanism and its potential protective effects on the articular cartilage in an experimental model consisting of 68 knees of adult dogs on which five different types of medial meniscectomy were performed. The results were assessed by macroscopic, microangiographic, and histological methods, after a sequential follow-up period of 10-450 days. Two different mechanisms of meniscal repair were observed, depending on whether meniscal section had been performed in vascular (total meniscectomy) or avascular (subtotal or partial meniscectomy) zones. It was also observed that the repaired meniscal tissue does not prevent articular cartilage degeneration. This is more closely related to the size of the meniscal fragment preserved at meniscectomy. Due to the biomechanical importance of the meniscus and the lack of functional relevance of the repaired meniscal tissue, the most conservative approach possible to meniscectomy is recommended.

Animals↗
PubMed1982

[Adjuvant chemotherapy for osteogenic sarcoma: analysis of the present situation and of factors which have influenced therapeutic results].

Although it has been used for more than ten years, the value of chemotherapy as an adjunct to surgery has not yet been firmly established. Uncertainties are related to the multiplicity of factors involved in disease progression, management, and evaluation of results. Therefore, it is important to know the results of ongoing or terminated therapeutic trials, in order to propose new guidelines for research and for improvement of therapeutic results. The purpose of this article is to analyse the published results from historical controls (USA and Europe), and the results obtained using chemotherapy in the most significant series reported, as well as a series of twenty-six cases treated by the GESO (Osteogenic Sarcoma Study Group) following two different programs. The results in this group are similar to results in classical historical controls and in therapeutic trials reported by other spanish centers, although they are worse than those recorded in our own historical controls retrospectively analysed. It seems that in our patients unfavorable prognostic factors are predominant so that our results are worse than those from other series. Therefore, new controlled trials are needed, with adequate grouping of cases, using a different preoperative chemotherapy regimen, and comparing results to those in control groups without further treatment.

Antineoplastic Agents↗
PubMedDate not supplied

Effect of polyethylene particles on human osteoblastic cell growth.

In this study, we have analyzed the direct effect of ultrahigh molecular weight polyethylene (polyethylene) on the osteoblastic cell growth in primary cultures. The cells were cultured from human bone samples obtained during reconstructive joint surgery. When cell cultures reached confluence (4-6 weeks) they were separated into three subcultures. One subculture was without particle addition (plain culture). In the other two subcultures, polyethylene or alumina was added. Two different sizes of particles were used, <80 and <160 microm. The subcultures were incubated until confluence. Proliferation of each subculture was measured by cell counts after 3, 6, 9 and 13 days, and the area under the curve (AUC) was calculated. Polyethylene particles of <160 microm induced a decrease in growth, whereas alumina of the same size did not. Polyethylene and alumina particles of <80 microm induced an inhibition in the osteoblastic cell growth; <80 microm polyethylene induced a higher inhibition than alumina of the same particle size. In conclusion, we have observed a direct effect of polyethylene on osteoblastic cell growth. This study shows that polyethylene may decrease the growth rate of human osteoblastic cells in primary cultures. Smaller particles produce a more marked reduction.

Biocompatible Materials↗
PubMedDate not supplied

Ultrasonographic and magnetic resonance images of rotator cuff lesions compared with arthroscopy or open surgery findings.

Our purpose was to compare the accuracy of ultrasonography (US) and magnetic resonance (MR) in the diagnosis of rotator cuff injuries (focusing on supraspinatus tears) using arthroscopy or open surgery findings. Using US and MR, we studied all painful shoulders seen during 1998 in our orthopaedic unit. Diagnosis was confirmed in 61 cases. The diagnosis of full thickness rotator cuff tear was highly specific on both imaging techniques (100% for US and 97.1% for MR) but was not as sensitive on US (57.7%) as on MR (80.8%). The diagnosis of partial tear was acceptably specific (67.9% for US and 75.5% for MR) but was not sensitive (overall, 12.5% for US vs 50% for MR). The specificity of a US diagnosis of a tear allows us to recommend surgery, thus making it a good imaging technique for the initial study of painful shoulders. The low sensitivity makes it necessary to undertake an additional MR study. If the MR also discovers no pathology, the sensitivity based on the US and MR images (92.7%) can be sufficient to avoid a false-negative diagnosis.

Arthroscopy↗
PubMedDate not supplied

Modulation of C4b-binding protein isoforms during the acute phase response caused by orthopedic surgery.

Orthopedic surgery is described as an event with a high risk of thromboembolic diseases. This is probably a consequence of a synergistic combination of different risk factors in the patients subjected to this type of surgery, including age, immobilization, anesthesia and different hypercoagulable states. After surgery patients develop an acute-phase response that leads to changes in several plasma proteins. One of these proteins is the complement regulator C4b-binding protein (C4BP). We have recently shown that in some acute-phase patients C4BP is incorrectly controlled (with elevation of the C4BP beta-containing isoforms), leading to a potential hypercoagulable state by decreasing the plasma levels of free (active) protein S. Here we have studied whether patients subjected to orthopedic surgery have an appropriate modulation of the C4BP isoforms during their postoperative acute-phase responses. We have analyzed the evolution of the C4BP isoforms in serial samples from 11 patients who have undergone knee (or hip) prosthesis surgery (mean age 70 years), or scoliosis surgery (mean age 18 years). Our data suggest a similar evolution of C4BP isoforms in all these patients, with an almost exclusive increase of C4BP isoforms lacking C4BP beta polypeptides and steady levels of free protein S.

Acute-Phase Reaction↗