Biomedical subjects

S Zaffagnini

Publications and source records attributed to S Zaffagnini.

At least 37 records · Page 2Linked to original sources

PubMed1998

pO2 measurement in an experimental model of patellar tendon autograft pro-anterior cruciate ligament.

Thirty-four sheep were submitted to surgery substituting the native ACL with the central third of the patellar tendon, ten enter this study. The purpose was to find a possible relationship between tissue pO2 and healing processes considering also the biomechanical and histomorphological aspects of the grafts. Four of them were sacrificed under general anaesthesia after 6 months, and six after 1 year in order to perform tissue pO2 measurement and an analysis of microvessel density on specimens of the normal ACL and the graft. Our data showed higher pO2 values of the autografts after 6 months. After 1 year the data was comparable to those of native ACL. This was confirmed by a microvessel count of the histological specimens and the data was in relationship to biomechanical and histomorphological analysis. Tissue pO2 can be observed and recorded in "in vivo" ACL, and patellar tendon used as graft, with no injury to their integrity. The monitoring system might be considered as an experimental tool for indirect controls of the anterior cruciate substitutes.

Animals↗

PubMed1998

Cryo/Cuff use after arthroscopic surgery: effect on knee joint temperature.

Any modality that alters joint homeostasis could have a potential negative effect on cartilage. During arthroscopic knee surgery, the temperature in the knee joint decreases significantly. The use of cryotherapy after this surgical procedure could maintain or increase these temperature variations. This prospective, randomized study evaluated the change in intra-articular knee temperature with the use of the Cryo/Cuff (Aircast Inc, Summit, New Jersey) in 30 patients after arthroscopic knee surgery. In 15 patients, a Cryo/Cuff with an automatic pump was applied immediately after surgery (group 1), and in the remaining 15 patients, only a wound dressing was applied (group 2). The mean intra-articular temperature at the beginning of the procedure was 34.8+/-1 degrees C for both groups. At the end of surgery, the temperature was 26.8+/-2.2 degrees C for group 1 and 27.5+/-2.2 degrees C for group 2. One hour after the end of the procedure, the mean temperature was 34+/-1.6 degrees for group 1 and 34.8+/-1.7 degrees C for group 2. These differences were not statistically significant. These results demonstrated that the use of the Cryo/Cuff does not alter temperature recovery in the knee, thereby excluding potential damage to the articular cartilage.

Adult↗

PubMed1997

Histological and ultrastructural evaluation of Leeds-Keio ligament six years after implant. A case report.

We examined by light and electron microscopy study a Leeds-Keio ligament removed from a patient 6 years and 4 months after implant following rupture. The new ligament presented an outer capsule made up of bundles of collagen fibres running mainly perpendicular to the long axis of the ligament. Septa were seen emerging from the capsule and composed of bundles of collagen fibres surrounding the bundles of Dacron fibres. Each thread of Dacron was surrounded by a layer of connective tissue containing periodic acid-Schiff (PAS)-positive cells. The bundles of collagen fibres making up the outer capsule, the septa and the layer of connective tissue surrounding the Dacron threads were positive for anti-type I collagen antibody. The rehabitated Leeds-Keio ligament presented a specific organization at the septa zone, showing a layer of collagen fibrils alternating with a layer of cells. Our remodelling findings suggest a shoelace effect of the artificial ligament. On the other hand, the presence of type I collagen could be responsible for the good functional behaviour of this composite system. In conclusion, the factors that play an important role in determining this remodelling process and its mechanical function are unknown.

Adult↗

PubMed1997

Total knee arthroplasty without patellar resurfacing in active and overweight patients.

Overweight patients are often considered poor candidates for total knee arthroplasty (TKA). A retrospective study of this was done on 47 osteoarthritic knees treated by TKA without patella resurfacing between March 1991 and June 1993. The Hospital for Special Surgery (HSS) rating system was used for clinical evaluation, and radiographs to study the degree of osteoarthritis and radiolucency. Correlations between overweight, range of motion (ROM) and stage of patellar damage and other measured variables (HSS score, patellar pain and radiolucency) were studied. Overweight was not correlated with HSS score, radiolucency or patellar pain. ROM was significantly correlated with patellar pain and HSS score, with better results in patients with ROM between 90 degrees and 110 degrees. Therefore, we believe that TKA in osteoarthritic knees can lead to successful results, even in active or overweight patients.

Aged↗

PubMed1996

Temperature changes in the knee joint during arthroscopic surgery.

Normal joint conditions are altered during arthroscopic surgery, and these changes have uncertain ultrastructural and biomechanical effects on articular cartilage. Experimental studies have shown that temperature variations affect the biomechanical properties of articular cartilage. We documented the temperature of the knee joint in 40 patients at the beginning and end of an arthroscopic procedure (anterior cruciate ligament reconstruction or meniscectomy). The intra-articular measurements were obtained using a digital thermometer connected to a sterile stainless steel probe. Correlation coefficients and linear regression techniques were used to determine which variables are independent predictors of joint temperature at the end of surgery. The mean knee joint temperature before surgery was 35.1 degrees +/- 1.0 degrees C and at the end of surgery 24.6 degrees +/- 1.5 degrees C. The joint temperature at the end of surgery was significantly affected by the temperature of the saline irrigant used and the length of arthroscopic procedure. The clinical implications of our findings must be clarified in animal models.

Adolescent↗

PubMed1996

Arthroscopic reconstruction of the anterior cruciate ligament with Leeds-Keio ligament in non-professional athletes. Results after a minimum 5 years' follow-up.

We report our experience using the Leeds-Keio artificial ligament for anterior cruciate ligament (ACL) reconstruction. The study relates the results of the first 40 patients subjected to arthroscopic reconstruction of the ACL with a Leeds-Keio ligament, with a mean follow-up of 73 months. No associated peripheral procedures were carried out on any patient. The average age of the patients at the time of the operation was 31 years (range 26-35 years). The rehabilitation protocol followed by all patients aimed at resumption of sport 4 months after the operation. Clinical assessment included IKDC and the Lysholm scoring scale. The KT-2000 system was used for instrumented evaluation of joint laxity. All patients underwent a radiographic check-up. Clinically there were 55% excellent or good results when using the IKDC scale, while with the Lysholm score, satisfactory results were obtained in 80%. Complete post-traumatic rupture of the ligament was observed in three patients. No patient suffered an episode of either hydrarthrosis or reactive synovitis, which indicates good tolerance to the ligament. The radiographic evaluation of the operated knees showed a close correlation between the appearance of degenerative phenomena and performance of arthroscopic meniscectomy. The results achieved with the Leeds-Keio artificial ligament 5 years after application, although not completely satisfactory and inferior to those obtained with autologous biological ligaments, should be considered an encouragement to promote new efforts in this interesting research field.

Adolescent↗

PubMed1996

Expression and regulation of glial-cell-line-derived neurotrophic factor (GDNF) mRNA in human astrocytes in vitro.

The expression and modulation of mRNA for glial-cell-line-derived neurotrophic factor (GDNF) in human glial cells was investigated. Astrocyte cell cultures were isolated from human fetal brains, characterized by immunocytochemistry and maintained in vitro in conditions of high purity; sister cultures were exposed to protein kinase C (PKC) inhibitors for 20 min. Total RNA was extracted from the cell pellets, reverse-transcribed into cDNA and amplified by the polymerase chain reaction (PCR) with primers specific for GDNF. A reverse-transcription/PCR procedure was also performed on mRNA extracted from human fibroblast and lymphocyte cell lines. Human astrocytes grown in the absence of neurons expressed detectable amounts of mRNA for GDNF but no amplification products were observed in fibroblasts and lymphocytes, thus confirming that GDNF production was cell-type specific. After exposure to PKC inhibitors, a dramatic down-regulation of GDNF mRNA was observed in astrocyte cell cultures. Thus, human astrocytes are constitutively capable of producing GDNF, such trophic activity is restricted to neural cells, and PKC plays key roles in signal pathways that regulate the gene activation and production of GDNF.

Astrocytes↗

PubMed1996

Arthroscopic management of recurrent anterior dislocation of the shoulder: analysis of technical modifications on the Caspari procedure.

Arthroscopic treatment was performed on 71 patients with recurrent shoulder dislocations; all of the patients had monoplanar anterior instability attributable to arthroscopically diagnosed Bankart lesion. Of the 71 operations, 29 were performed using the original Caspari technique (follow-up, 59 months), and 42 were performed after modifications made in the original technique (follow-up, 38 months), notably improved preparation of the capsular reinsertion zone and increase in the number of monofilament points and their anchorage directly to the bone, on the spine of the scapula. We compared the results obtained in these two differently treated groups, taking into account several factors in the patient's history and clinical condition. These included the number of dislocation episodes before the operation, as well as clinical findings regarding stability, movement, function and pain (Rowe scale score), contralateral shoulder laxity, level of preoperative versus postoperative athletic activity, and postoperative recurrence rate. In the Caspari-treated group, we obtained 66% satisfactory results compared with the 90% obtained in the second group. The recurrence rate was 27% in the first group compared with 4.8% in the second group. These data were statistically significant. No correlation was found between preoperative number of dislocations and recurrence rate, nor for contralateral shoulder laxity. No significant difference was found regarding resumption of sport activity in the two groups. Our data indicate that, with accuracy in patient selection and effective surgical technique, the recurrence rate can be reduced, and results similar to those of the arthrotomic technique may be obtained.

Adolescent↗

PubMed1995

Results in the treatment of recurrent dislocation of the patella after 30 years' follow-up.

The authors compare the clinical and radiographic outcome in patients with comparable bilateral recurrent patellar dislocation treated surgically on only one side, to clarify the appropriateness of the surgical indication. Sixteen patients were evaluated at an average follow-up of 30 years (20-45); all had been treated by the Roux technique. The results on both the operated and the unoperated knee were evaluated; the Crosby and Insall schedule was used for the clinical evaluation. Anteroposterior, lateral, and Merchant's view X-rays were examined for osteoarthritis and to measure the height of the patella. The congruence angle and the distance between anterior tibial tuberosity and trochlear groove (ATT-TG) were measured by computed tomography. The results in the operated knees were: 3 excellent, 9 good, 1 fair, and 3 worse; results in the nonoperated knees were 6 excellent, 8 good, 1 fair, and 1 worse. In the operated knees arthritis was grossly marked in 8, marked in 3, moderate in 1, and light in 4; in the nonoperated ones it was grossly marked in 8, moderate in 3, and light in 5. The congruence angle was normal in 10, medially displaced in 3, and laterally displaced in 3 cases on the operated side; on the nonoperated side it was normal in 7 cases and lateralized in the remaining 9. The ATT-TG in the operated knees was negative in 9 cases, normal in 1, and positive in 6; on the non-operated side it was positive or normal. In 7 operated cases a low patella was documented. The Roux technique yields positive results in the correction of recurrent dislocation. No clinical or radiographic differences were found between surgically and conservatively treated knees. The clinical results are generally not comparable with the radiographic features or with severity of degenerative modifications presented at long-term follow-up. The absence of a difference is due basically to the complete lack of adaptation of the surgical procedure to the variable pathogenesis of this disorder.

Adolescent↗

PubMed1993

Comparison between laser meniscectomy with excimer and Ho:YAG lasers.

The authors report their experiences using the excimer laser and holmium:YAG laser in arthroscopic meniscal surgery. Histologic and ultrastructural aspects caused by laser irradiation on meniscal tissues are evaluated. Two groups of 10 patients, each suffering from a bucket-handle lesion of the internal meniscus, were used for this study. The histologic results of the study confirm the clinical reliability of the laser even in the presence of different ultrastructural frames.

Arthroscopes↗

PubMed1992

The human anterior cruciate ligament: histological and ultrastructural observations.

In transverse and longitudinal paraffin-embedded sections, the human anterior cruciate ligament (ACL) is made up of wavy bundles of collagen fibres arrayed in various directions, the majority around the axis of the ligament with a few running parallel to it. The fascicles making up the larger bundles are also characterised by this undulating appearance. In thin sections 2 types of collagen fibrils are observed: small (with a single diameter peak at 45 nm) and large (3 peaks at 35, 50 and 75 nm respectively), organised into distinct areas made up of either large or small bundles of fibrils. The numerous fibroblasts that are present appear elongated in the direction of the bundles with branches and short cytoplasmic processes. The elastic system is made up of both elastic and oxytalan fibres. The varied orientation of the bundles in the ACL, the complex ultrastructural organisation and the abundant elastic system make it very different from other ligaments and tendons, providing a structure able to withstand the multiaxial stresses and varying tensile strains imposed upon it.

Anterior Cruciate Ligament↗

PubMed1991

Histologic and ultrastructural findings of tissue ingrowth. The Leeds-Keio prosthetic anterior cruciate ligament.

A light and electron microscopy investigation was performed on a Leeds-Keio ligament removed because of rupture 18 months after implantation to repair an anterior cruciate ligament. The investigation showed fibrous connective tissue on the plane of the main stress force. There was elastin and adequate vascularization interspersed with Type I collagen fibrils in the area most distant from the ligament. The tissue near the Dacron fibers was highly cellular with a matrix of infrequent, thin collagen fibrils and abundant fine granular material. The growth of the host tissue occurred in and around a Leeds-Keio ligament in response to tensile stresses.

Adult↗

PubMedDate not supplied

Rotational laxity after anterior cruciate ligament injury by kinematic evaluation of clinical tests.

Despite the numerous studies on anterior cruciate ligament biomechanics and clinical tests, some disagreements still exist in the literature on the role of ACL in restraining rotations and which kinematic test after ACL injuries is the most suitable to evaluate this instability. This work analyses the capability of passive clinical and stress tests to detect an ACL state quantifying rotational instability. The study was conducted on animal knees with a new protocol. We found that an internal-external stress test can give a useful indication on the ACL state when used to estimate the side to side differences while varus-valgus laxity and secondary motions in standard kinematic tests did not seem to be affected by ACL injury. The kinematic protocol performed could be used intra-operatively to quantify rotations, allowing a more accurate evaluation of knee instability to guide surgical reconstruction and improve its final outcome.

Animals↗

PubMedDate not supplied

Early versus late reconstruction for anterior cruciate ligament rupture. Results after five years of followup.

We investigated the clinical and laxity testing results at 5 years' followup in patients who had early or late anterior cruciate ligament reconstruction. Twenty-three patients (Group I) were treated within 15 days of injury. Fifty-nine patients (Group II) were treated more than 3 months after injury. Patellar tendon reconstruction and fascia lata graft augmented with a ligament augmentation device were the techniques used in both groups. According to the International Knee Documentation Committee rating scale, 17 patients in Group I and 38 patients in Group II had satisfactory results. The Lysholm score was good in all Group I patients and in 55 Group II patients. Flexion-extension deficits were comparable for both groups. Eighteen patients (78%) in Group I demonstrated satisfactory results according to the KT-2000 arthrometer testing, compared with 44 (75%) in Group II. No associated lesions were present in 12 (52%) cases in Group I, compared with 26 (44%) cases in Group II. Return to sports at the preoperative level was obtained by 21 (91%) patients in Group I, compared with 42 (71%) in Group II. The patients who had reconstruction during the early phase returned to sports activities sooner and had better clinical and laxity testing results.

Adolescent↗

PubMedDate not supplied

New cell-based technologies in bone and cartilage tissue engineering. I. Bone reconstruction.

A tissue engineering, cell-based therapeutic approach could be essential for extensive bone or cartilage reconstruction. This article is divided in two chapters and describes new cell-based surgical techniques for cartilage and bone reconstruction. In the first part on bone reconstruction, marrow-derived osteogenic progenitor cells combined with hydroxyapatite were utilized. The validity of this model has been shown for the repair of critical size bone defects in large size animal models. We used this cell-based therapeutic approach to treat 3 patients with large bone defects, achieving bone reconstruction.

Adolescent↗

PubMedDate not supplied

New cell-based technologies in bone and cartilage tissue engineering. II. Cartilage regeneration.

A tissue engineering, cell-based therapeutic approach could be essential for extensive bone or cartilage reconstruction. This article is divided in two chapters and describes new cell-based surgical techniques for cartilage and bone reconstruction. The second part of the article, regarding cartilage repair, describes a new arthroscopic surgical technique for tissue engineered cartilage grafting. A 3-dimensional hyaluronic acid support is used for autologous chondrocyte culturing. The technique reduces morbidity of classic autologous implant avoiding open surgery and periosteal flap use. With this technique is possible to reduce the patient morbidity, time and cost of surgery.

Adolescent↗

PubMedDate not supplied

The preliminary results of press-fit knee arthroplasty without a patellar component.

A total of 22 cases of Kinemax prostheses implanted consecutively from January to June 1990 for the treatment of primary gonarthrosis were evaluated; in these cases remodeling of the patella was performed, and the corresponding component of the prosthesis was not used. The mean age of the patients was 64 years, mean follow-up was obtained after 48 months. According to the HSS form results were: excellent: 9 (40.9%); good: 12 (54.5%); fair: 1 (4.6%). The postoperative femorotibial axis measured a mean of 173.8 degrees. There were no complications in the patella, only in 1 case did we observe mild anterior pain. Knee arthroplasty without substitution of the patella seems to guarantee good results in patients with primary gonarthrosis, as long as patellar reconstruction is performed and correct femoropatellar alignment is guaranteed, as well as recovery of the femorotibial axis with accurate positioning of the prosthetic components.

Aged↗

PubMedDate not supplied

Total knee arthroplasty after proximal tibial osteotomy.

The cases of ten total knee arthroplasty after a proximal tibial osteotomy were compared with those of 50 primary total knee arthroplasty for osteoarthritis. The groups were matched according to age of patients, length of follow-up and type of prosthesis used. On the basis of HSS, an excellent or good result was obtained in 90% of patients who had had arthroplasty after osteotomy and in 94% of patients after a primary arthroplasty. Though some intraoperative difficulty may be encountered in a secondary prosthesis, osteotomy does not compromise a subsequent arthroplasty.

Aged↗