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Biomedical subjects

A J Tonino

Publications and source records attributed to A J Tonino.

At least 19 recordsLinked to original sources
PubMed2005

Periprosthetic fractures around cementless hydroxyapatite-coated femoral stems.

We studied 14 periprosthetic femoral fractures out of a series of 619 hydroxyapatite coated hip implants and compared the outcome to published treatment algorithms using the Vancouver classification. There were five type A fractures, six B1, two B2, and one type B3 fracture. All but one type A fractures were treated conservatively. Compared with the Vancouver classification, we observed a different fracture type in the type B fractures. No fractures at the tip of the stem were seen, as in cemented implants. Three B1 fractures were treated operatively due to fracture displacement, and three were treated conservatively. The B2 and B3 fractures were managed with long, uncemented, revision stems because of a disrupted bone-prosthesis interface. All fractures healed well. This study confirms that the modified algorithm of management of periprosthetic fractures, using the Vancouver classification, is a simple, reproducible, classification system for uncemented prostheses. Conservative treatment is a valid option if the implant is stable whilst surgical intervention is mandatory if the implant is loose.

Aged↗
PubMed2003

Cementless mallory-head HA-coated hip arthroplasty for osteoarthritis in hip dysplasia.

Sixty-three cementless Mallory-Head HA-coated femoral prostheses (Biomet, Warsaw, IN) were used in primary total hip arthroplasty in 50 patients with osteoarthritic hips because of congenital hip dysplasia. The implanted cup was also cementless (41 Harris Galante and 22 Ringlock). The patients were followed up for a mean period of 75.1 months (range, 44-110). Clinical and radiologic analysis were performed. Harris Hip Score increased from 42 to 90 points; 97% of the patients had no or only mild pain, and limping decreased from 90% to 20%. Complications were marginal: no infections, one habitual dislocation, one peroperative fracture of the femur, and one transient ischiadic nerve palsy. Two HG cups were revised for augmented polyethylene wear. Radiographically, no subsidence of the prosthesis or bone atrophy of the proximal femur could be detected. No correlations were found between the radiologic phenomena and the clinical outcome, but the tightness of the prosthesis fit had a definitive influence on the radiographic bone remodeling pattern. The cementless Mallory-Head HA-coated femoral prosthesis shows excellent clinical and radiological mid-term results in osteoarthritic hip dysplasia patients. There was no need for the use of a specially designed dysplasia femoral prosthesis.

Adult↗
PubMed2002

Osseointegration of hydroxyapatite-coated and noncoated Ti6Al4V implants in the presence of local infection: a comparative histomorphometrical study in rabbits.

A study was designed to investigate the osseointegration of titanium implants, either noncoated or coated with hydroxyapatite (HA), into rabbit tibiae in the presence of local infection compared with osseointegration in the absence of local infection. HA-coated or noncoated Ti cylinders were implanted into both tibiae of 32 rabbits (New Zealand Whites). Before implantation the left tibia was contaminated with different quantities of Staphylococcus aureus (10(2)-10(5) CFU). Four weeks after surgery the tibiae were explanted and prepared for microbiological and histomorphometrical examination. Histomorphometrical data, as a representation of implant fixation, were obtained by measuring the percentage of bone around the implants (within a radius of 1 mm from the outer diameter of the implants) and the percentage of the circumference of the implant that was in direct contact with bone. Histomorphometry revealed, in particular for the HA implants, a relationship between the inoculum concentration and/or the presence or absence of infection with the bone contact at the distal implant side. This confirms a relationship between peri-implant infection and bone contact or remodeling. HA-coated implants developed, in the presence of bacteria, more easily a more severe infection than noncoated Ti implants, and we show in the present study that local infection will influence histomorphometrical parameters (bone-implant contact) that determine implant fixation. Precautions to prevent contamination (asepsis) and/or infection (perioperative antibiotics) are even more important for the highly biocompatible HA-coated implant.

Alloys↗
PubMed2001

Hydroxyapatite coated hip prosthesis followed up for 5 years.

We prospectively studied 250 patients with a proximal hydroxyapatite coated hip prosthesis. The follow-up period was 5 years. All components showed osseointegration except for one deep infection. The morphology of bone remodeling with either endosteal bone formation or periosteal bone formation was dependent on the way the stem filled the medullary canal. No linear or distal osteolysis around the stems was observed.

Adult↗
PubMed2000

Effects of hydrosyapatite coating on Ti-6A1-4V implant-site infection in a rabbit tibial model.

To investigate the effect of implant type after direct contamination, a hydroxyapatite-coated or noncoated Ti-6A1-4V implant was inserted into both tibiae of 32 New Zealand White rabbits. Prior to implantation, the left tibia was contaminated with increasing concentrations of Staphylococcus aureus (10(2)-10(5) colony-forming units), ranging from very low (10(2)) to relatively high (10(5)). Four weeks after implantation, half of the tibial bone adjacent to the implant was harvested for bacteriological examination. Bacterial counts were quantified by plating serial dilutions. For the histological evaluation, sections of the implant with the remaining tibia were examined by semiquantitative scoring of infection parameters. The bacteriological data showed the inoculum dose and implant type to have a significant effect on the culture outcome: more bacteria were retrieved from the hydroxyapatite-coated implants than from the noncoated titanium implants. Histological evaluation showed an increased score for the infected left tibiae compared with their contralateral control. In addition, with increasing inoculum dosage, the difference between the two types of implant increased. We demonstrated that infections can occur with biocompatible, noncemented implants and that they are related to the dose of the original inoculum. Bacteria were more likely to grow onto or next to the hydroxyapatite implants than on titanium implants and resulted in a more severe histopathological characterization of infection.

Aluminum↗
PubMed2000

The hydroxyapatite-ABG hip system: 5- to 7-year results from an international multicentre study. The International ABG Study Group.

A proximally hydroxyapatite (HA)-coated hip prosthesis designed for proximal stem bonding and stress transfer was studied in a consecutive series of 398 patients in an ongoing, prospective multicenter study. Follow-up was 5 to 7 years. The clinical results were excellent with a mean preoperative Merle d'Aubigné score of 8.5 and 17.3 at 5 years. Only mild thigh pain not necessitating analgesics or a walking stick was reported in 3.6% at 5 years. Three cups and 3 stems had to be revised, all before the 2-year assessment and mainly for technical reasons. No components needed revision after 2 years. The 5-year HA-coated component survival was 99.2%. Serial radiographs showed excellent osseointegration, which was independent of pre-existing bone stock. The rate of radiographic bone remodeling was highest during the first 3 years, and positive bone remodeling (bone formation) preceded negative bone remodeling (bone resorption). The concept of transitional load transfer from proximal to distal could be acknowledged, with proximal load transfer highest in 77%. The combination of anatomic stem design with distal overreaming and proximal HA coating was thought to be the reason for these excellent results. Proximal circumferential osseointegration seems to be real because no linear or distal osteolysis was observed.

Adult↗
PubMed1999

Spontaneous or traumatic premature closure of the tibial tubercle.

A premature closure of the physis of the tibial tubercle in a young man has given rise to a shortening of the tibia, a patella alta and a reversed tibial slope of 20 degrees with clinical genu recurvatum. After a proximal open wedge tibial osteotomy all three postural deformities could be restored. The etiology of this complex deformity is discussed.

Adolescent↗
PubMed1999

Hydroxyapatite-coated femoral stems. Histology and histomorphometry around five components retrieved at post mortem.

We performed a histological and histomorphometric examination in five cadaver specimens of the femoral and acetabular components and the associated tissue which had been recovered between 3.3 and 6.2 years after primary total hip arthroplasty (THA) using a proximal hydroxyapatite (HA)-coated titanium alloy implant. All had functioned well during the patients' life. All the stems were fixed in the femur and showed osseointegration of both the proximal and distal parts. The amount of residual HA was greatest in the distal metaphyseal sections, indicating that the rate of bone remodelling may be the main factor causing loss of HA. The level of activity of the patient was the only clinical factor which correlated with loss of coating. The percentage of bone-implant osseointegration was almost constant, regardless of the amount of HA residue, periprosthetic bone density or the time of implantation. HA debris was seldom observed and if present did not cause any adverse or inflammatory reaction. Partial debonding did occur in one case as a result of a polyethylene-induced inflammatory reaction.

Aged↗
PubMed1997

Nerve injury after hip arthroplasty. 5/600 cases after uncemented hip replacement, anterolateral approach versus direct lateral approach.

In 600 consecutive uncemented total hip replacements, 2 surgical approaches were used: the direct lateral Hardinge approach in supine position (group I: 241 cases) or in a lateral position (group II: 280 cases) and the anterolateral Watson-Jones approach in supine position (group III: 79 cases). 5 patients had clinically evident peripheral nerve injuries confirmed with EMG: none in group I, 1 lesion of the nervus ischiadicus and nervus femoralis in group II and 4 nervus femoralis lesions in group III, of which 1 was combined with an obturator nerve injury. The nerve injuries were evaluated with EMG. All 4 nervus femoralis lesions recovered spontaneously, but the one patients in group II had a persistent palsy of the peroneal nerve. The anatomical basis for the higher prevalence of nervus femoralis lesions in the anterolateral Watson-Jones approach is described.

Aged↗
PubMed1997

Results and complications after posterior lumbar spondylodesis with the "Variable Screw Placement Spinal Fixation System".

Between March 1988 and March 1990, 45 patients underwent a spondylodesis using transpedicular screws and plates of the "Variable Screw Placement Spinal Fixation System". The indications for operation were spondylolisthesis (13), spondylolisthesis plus discopathy at the adjacent level (4), degenerative discopathy (13), pseudarthrosis after interbody fusion (7), disc herniations (4) and disc herniations plus degenerative discopathy of the adjacent segment (4). In 1992, 43 patients were available for follow-up. The mean follow-up was 3.85 years. Side effects or complications of a more permanent character were seen 25 times in 43 patients. Eight patients had evidence of screw failure: loosening (5), fracture (2), and malposition (1). Complications, screw failure and reoperation all adversely affected clinical outcome. Overall only 60% of the patients reported a positive clinical outcome at follow-up. In our opinion transpedicular instrumentation is a logical system to provide rigid stabilisation, but it has a high learning curve. The original V.S.P. system with its bulky plates and screws appears to be particularly prone to giving a high rate of unwanted side effects not offset by a high clinical success rate.

Activities of Daily Living↗
PubMed1996

Acute whiplash injury: is there a role for MR imaging?--a prospective study of 100 patients.

PURPOSE: To evaluate the findings from magnetic resonance (MR) imaging of the cervical spine and brain after acute whiplash injury. MATERIALS AND METHODS: Within 3 weeks of trauma, 100 patients underwent MR imaging for evaluation of the cervical spine and the brain. In addition, plain radiographs were obtained, including functional images of the cervical spine. RESULTS: Only one patient had an abnormality on the MR image that was related to trauma (ie, prevertebral edema). In 17 patients, functional images showed a kyphotic angle, but no evidence of soft-tissue injury was seen on MR images. CONCLUSION: There is no role for MR imaging in the routine work-up of patients with acute whiplash injury who have normal plain radiographic findings and no evidence of a neurologic deficit. A kyphotic angle seen on functional images of the cervical spine should not be assumed to indicate soft-tissue injury and is most likely attributable to a compensating mechanism of hypermobility at a level of the spine above that at which hypomobility occurs, which is probably the result of a muscle spasm.

Acute Disease↗
PubMed1995

Hydroxyapatite-coated hip prostheses. Early results from an international study.

A hydroxyapatite-coated hip prosthesis designed to stimulate proximal femoral stress transfer was studied in 222 patients undergoing primary total hip arthroplasty with a minimum followup of 2 years. The femoral component was a roughened titanium alloy with a 50-mu coating of hydroxyapatite applied to the proximal third. A proximal press-fit technique was applied with distal femoral over-reaming as standard procedure. The hydroxyapatite-coated acetabulum was of hemispherical design. Analysis of the clinical results showed a mean Merle D'Aubigné score of 16.7 points at 6 months and 17.4 points at 2 years. Mild residual thigh pain of unknown origin was reported in 3.6% of patients at 2 years. Radiographic evaluation showed complete acetabular and proximal femoral osseointegration without any loosening. No radiolucency or reactive line formation was observed around the hydroxyapatite-coated areas of the prostheses. Femoral bone densification occurred at the coated-uncoated transition zone (54%); 4% to 6% of cases showed cortical hypertrophy at the uncoated area of the stem. Reactive lines were seen around the distal stem in 52% of patients after 2 years. The clinical outcome was excellent, and the radiographic data pointed mainly to proximal femoral stress transfer.

Adult↗
PubMed1994

Quantitative analysis of technetium-99m-methylene diphosphonate uptake in unilateral hydroxyapatite-coated total hip prostheses: first year of follow-up.

UNLABELLED: A prospective study was performed on 80 patients who had undergone a unilateral hydroxyapatite (HA)-coated total hip arthroplasty to establish the normal periprosthetic uptake of methylenediphosphonate (MDP) as a function of implant age. METHODS: Patients were imaged periodically while they were asymptomatic at 1, 3, 6 and 12 mo postoperatively. Quantitative measurements were performed with a region of interest (ROI) technique. The HA-coated and uncoated areas were marked in comparison with the normal contralateral femur. The uptake ratios of the MDP were determined postoperatively in the following 12 mo. RESULTS: It was found that a decrease of the uptake ratios occurred in all ROIs. However, for the HA-coated areas, the uptake ratios still remained raised as a result of bony ingrowth. CONCLUSION: The results of the first year of follow-up were considered to be a normal database that will be used as a reference when the same group of patients are followed up to 5 yr postoperatively to detect any potential modes of failure of the implant.

Durapatite↗
PubMed1993

Aseptic spondylodiscitis: a complication of chemonucleolysis? A case report.

Discitis after intradiscal injection of chymodiactin is nearly always associated with an infection introduced by the needle tip. The authors report a patient with a postchemonucleolysis spondylodiscitis who recovered complete without surgery or antibiotics. The clinical findings and results of CRP and MRI suggested an aseptic spondylodiscitis due to chymodiactin.

Adult↗
PubMed1990

Long-term results of arthrodesis of the ankle.

Forty-four arthrodeses of the ankle were carried out between 1965 and 1984 in forty-three patients with post-traumatic osteoarthritis or poliomyelitis. Twenty-eight patients, one of whom had a bilateral arthrodesis, were followed up after an average of ten years. Twenty-four were satisfied and the patients with poliomyelitis were better than those with osteoarthritis. The condition of the tarsal joints before the operation influences the result, but the arthrodesis does not cause degenerative changes in these joints.

Adolescent↗
PubMed1988

Bank bone grafts in revision hip arthroplasty for acetabular protrusion.

In 23 revision hip arthroplasties in which acetabular protrusion was encountered, homologous bone grafting was used to reconstruct or reinforce the medial wall of the acetabulum. Loosening of the acetabular component was the cause of the protrusion in all the cases. Postoperative follow-up showed a solid bone socket around the acetabular cup in all the cases and no signs of loosening at 3-years' follow-up.

Acetabulum↗
PubMed1985

Radiotherapy in the prevention of recurrence of paraarticular ossification in total hip prostheses.

Ectopic bone formation or paraarticular ossification after total hip arthroplasty can be a very disabling factor. In patients with this problem, range of motion and walking ability may be reduced and pain can occur. In severe cases it seems logical to remove this paraarticular ossified tissue, but without measures to prevent its recurrence this will be of no real value. This study shows the effectiveness of irradiation soon after excision of the ectopic bone mass, with a total dosage of 20 Gy (2000 rad) given in ten fractions, in preventing, or at least inhibiting, the recurrence of paraarticular ossification in 16 patients. A dramatic improvement in hip function, walking ability, and relief of pain is demonstrated.

Aged↗