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Biomedical subjects

E A Mäkelä

Publications and source records attributed to E A Mäkelä.

At least 19 recordsLinked to original sources
PubMed2003

Gamma probe localization in the surgical treatment of osteoid osteoma.

BACKGROUND: Osteoid osteoma is a benign bone tumor typically inducing night pain. It has traditionally been treated with operative excision. An accurate localization and complete removal of the small lesion is difficult resulting in high recurrence rate and reoperations. AIMS: The purpose of the present study was to examine the applicability of a hand-held gamma probe in the intraoperative localization of an osteoid osteoma. MATERIAL AND METHODS: Five patients were examined and operated for osteoid osteoma. Dose of 740 MBq Technetium 99m was injected 3 hours before operation, and hand-held gamma probe was used for the intraoperative detection of the lesion. RESULTS: All patients were relieved their symptoms. A histologically confirmed, complete removal of the lesion was achieved in 4 of 5 patients. No recurrences has been seen in the follow-up of 6 years. CONCLUSIONS: The gamma probe is an useful tool in the surgical treatment of osteoid osteoma. The technique is rapid and simple resulting in more accurate excision of the small lesion.

Adult↗
PubMed2002

Percutaneous bone grafting in the treatment of the delayed union and non-union of tibial fractures.

The classic method of open bone grafting in the treatment of un-united tibial fractures has been associated with some complications. A novel, minimally invasive, percutaneous technique of bone grafting is described. Forty-one consecutive patients with delayed union or non-union of a tibial fracture was treated with percutaneous bone grafting from 1993 to 1999. The mean age of the patients was 41 (15-86) years. Twenty-seven patients had grade I-III open fractures. The fractures had initially been treated in a cast (n=26), external fixator (n=14) or intramedullary nail (n=1). Two patients had an earlier unsuccessful Phemister-Charnley-type bone-grafting procedure for delayed union. The mean interval from injury to percutaneous bone grafting was 21 (13-66) weeks. Thirty-seven of the 41 un-united fractures healed in 13 (10-48) weeks after the percutaneous bone grafting. The mean hospital stay was 1 day. No infections, bleeding or neural complications existed. Percutaneous bone grafting appeared to be as effective as open techniques, and possessed considerable advantages. It is safe, time saving and economical, it involves minimal trauma at the fracture site and it avoids major donor site problems.

Adolescent↗
PubMed2001

[Bone tumors].

Explore the source record for details and available documents.

Bone Neoplasms↗
PubMed2000

Bioabsorbable fixation in orthopaedic surgery and traumatology.

Bioabsorbable internal fixation devices were introduced clinically in the treatment of fractures and osteotomies of the extremities at the Department of Orthopaedics and Traumatology, Helsinki University, in 1984. Since November 5, 1984, a total of 3200 patients were managed using bone or ligament fixation devices made of self-reinforced (matrix and fibres of the same polymer) bioabsorbable alpha-hydroxy polyesters. The devices used included cylindrical rods, screws, tacks, plugs, arrows, and wires. The most common indication for the use of bioabsorbable implants was the displaced malleolar fracture of the ankle. Transphyseal fixation with small-diameter, mainly polyglycolide pins was used in children. The postoperative clinical course was uneventful in more than 90% of the patients. The complications included bacterial wound infection in 4% and failure of fixation in 4%. In one-fifth of the latter cases, however, re-operation was not necessary. The occurrence of non-infectious foreign-body reactions two to three months postoperatively has been observed in 2% of the patients operated in the last few years with polyglycolide implants but none of the patients managed with polylactide implants. This inflammatory tissue response often required aspiration with a needle but did not influence the functional or radiologic result of the treatment. Owing to the biodegradability of these internal fixation devices, implant removal procedures were avoided. This results in financial benefits and psychological advantages. Bioabsorbable implants can also be used in open fractures and infection operations.

Absorbable Implants↗
PubMed2000

Strength retention of self-reinforced drawn poly-L/DL-lactide 70/30 (SR-PLA70) rods and fixation properties of distal femoral osteotomies with these rods. An experimental study on rats.

Self-reinforced polylevo-dextro-lactic acid (SR-PLA) 70 composite rods, (2 mm x 26 mm) were implanted in the dorsal subcutaneus tissue of sixteen rats. Osteotomies of the distal femur were fixed with SR-PLA70 composite rods (2 mm x 15 mm) in 39 rats. The follow-up times varied from 1 week to 1 year. After sacrifice three-point bending and shear tests were performed for subcutaneously placed rods, and radiological, histological, histomorphometrical, microradiographic, and oxytetracycline-fluorescence studies of osteotomized and intact control femora were performed. At 52 weeks the shear strength and flexural modulus of the rods were 41% of the initial value, and the flexural strength was 43% of the initial value. In the osteotomies seven specimens had to be excluded due to postoperative infection or dislocation of the fragment. Six of the thirty-two evaluated osteotomies showed signs of postoperative infection. Twenty-six osteotomies healed uneventfully. No signs of inflammatory or foreign-body reaction were observed. The present investigation demonstrated that the mechanical strength and fixation properties of the SR-PLA70 rods are suitable for fixation of cancellous bone osteotomies in rats. The present article is the first report on successful application of SR-PLA70 rods for fixation of cancellous bone osteotomies studied.

Animals↗
PubMed1999

Application of a self-reinforced polyglycolic acid (SR-PGA) membrane to the closure of an abdominal fascial defect in rats.

The suitability of a polyglycolic acid (PGA) membrane to fascial closure was tested in 40 rats. To induce collagen synthesis, a fascial strip from the vastus lateralis muscle was applied to the peritoneal side of the PGA membrane. A midline laparotomy was performed, and the incision was covered with the membrane fixed at the edges. The animals were sacrificed at 3, 6, 12, and 28 weeks, at which time macroscopical, histological, and electron microscopical findings, as well as the results of breaking force tests were evaluated. Fascial augmentation had no effect on the results. Ventral hernias were observed in 37.5% of the cases, half of which were observed after 6 weeks postoperatively. In one case, intestinal adhesions to the membrane were found. Inflammatory reaction during the follow-up was moderate and lasted up to 12 weeks. Breaking force decreased up to 6 weeks, after which it slightly increased without reaching the breaking force level of the control animals.

Abdominal Injuries↗
PubMed1998

Mechanical properties and strength retention of carbon fibre-reinforced liquid crystalline polymer (LCP/CF) composite: an experimental study on rabbits.

A novel composite material with ultra-high flexural strength and cortical-bone-matched elastic modulus made of liquid crystalline polymer reinforced with carbon fibres (LCP/CF) is described. Cylindrical rods of 3.2 mm diameter and 50 mm length were fabricated by a preimpregnation/pultrusion method. The initial mechanical properties of the LCP/CF rods were as follows: flexural strength 448 MPa, flexural modulus 43 GPa, shear strength 164 MPa, and interlaminar shear strength 15.3 MPa. In the in vitro study the LCP/CF rods were immersed in phosphate-buffered saline of 37 degrees C for 12, 24, and 52 weeks. In the in vivo study the LCP/CF rods were implanted into the medullary cavity of both femora and subcutaneous tissue of the New Zealand White rabbits for 12, 24, and 52 weeks. The flexural strength of the LCP/CF rods at 52 weeks was 463 MPa in saline, 467 MPa in the subcutaneous tissue and 466 MPa in the medullary cavity of the femur. The flexural modulus was 44.6, 48.9 and 46.2 GPa, respectively. The corresponding shear strength values were 160, 178 and 181 MPa. We conclude that the LCP/CF is a promising material for high-load applications and the LCP/CF rods retain their initial mechanical properties in one-year follow-up in vivo and in vitro.

Animals↗
PubMed1996

Characteristics of poly(L-)lactic acid suture applied to fascial closure in rats.

A new poly(L-)lactic acid (PLLA) thread was tested by applying it in fascial closures of male Wistar rats. The tissue reactions around the thread and in the fascial union, and the changes on the surface and the mechanical properties of the thread were evaluated at 1, 3, 6, 12, 28, and 52 weeks following surgery. Histologically, the extension of the general inflammatory reaction and the number of the different cell types did not markedly change during the 52-week follow-up period. The surface of the thread was intact up to 28 weeks when examined with the scanning electron microscope. At 52 weeks no thread was found. The breaking force and the stretching of the incubated PLLA thread was reduced about 20% during the first 2 weeks and it remained constant up to 6 weeks. The in vivo testing of the fascial strips closed with the PLLA thread retained their resistance against the breaking force, nearly comparable to that of the intact control fascial strips. It can be concluded that the PLLA thread is a suitable suture for wounds that require healing time of up to 28 weeks and thus need good support from the suture.

Abdominal Muscles↗
PubMed1996

Metallic or absorbable implants for ankle fractures: a comparative study of infections in 3,111 cases.

Absorbable fracture fixation has been in clinical use since 1984. Our study compares the infection rates and some infection parameters between metallic (2073 patients) and absorbable fracture fixation devices (1012 patients) in displaced ankle fractures. The infection rate associated with metallic fixation was 4.1%, compared with 3.2% absorbable fixation (p 0.3). The patients who had a wound infection were older when metallic fixation was used (p 0.01). They also had a bi- or trimalleolar fracture more often than did patients treated with absorbable fracture fixation, but this difference did not have a significant effect on the wound infection rate (p 0.2). The infections were mostly caused by microorganisms of the Staphylococcus species. Deep infections were equally common with both fixation methods (0.4%), but there was some variation in the bacterial spectrum.

Adolescent↗
PubMed1995

Effect of self-reinforced polyglycolide membranes on cortical bone: an experimental study on rats.

A self-reinforced polyglycolide (SR-PGA) membrane has been developed recently by our research group and testing of it begun. To study the behavior of this membrane and its effect on cortical bone, 93 Wistar rats were operated on. SR-PGA membrane was applied around the rats' femoral diaphyses, either over the periosteum or directly over the bone, after periosteal stripping. In a control group no membrane was applied, but the femoral periosteum was stripped away. The rats were sacrificed 1, 3, 6, 12, 24, and 30 weeks postoperatively. Radiology, histology, oxytetracycline fluorescence labeling, microradiography, and planimetry were used to determine the outcome. A fibrous tissue capsule had formed around and replaced the membrane. SR-PGA membrane had a positive effect on new bone formation. Callus was frequently seen proximally and distally to the implant. Periosteal thickening occurred whether or not SR-PGA membrane was used. PGA fibers decreased in number and diameter continuously until they vanished by 30 weeks. No infections or adverse reactions were encountered. Accordingly, SR-PGA membrane is considered to be biocompatible and applicable in the treatment of cortical bone lesions such as comminuted fractures and defects.

Animals↗
PubMed1995

Strength retention of self-reinforced polyglycolide membrane: an experimental study.

Self-reinforced polyglycolide (SR-PGA) devices are stronger than non-reinforced ones. To study the strength retention of SR-PGA membrane, in vitro and in vivo, membranes were either immersed in distilled water at 37 degrees C, or implanted in the subcutis or around the femoral bone of rats. The SR-PGA membranes lost their strength in vitro by 6 wk, while they retained it for 15 wk in vivo due to the fibrous tissue that formed around and inside the implant (biomembrane). This is an advantage when clinical application of the membrane is being considered.

Animals↗
PubMed1995

Repair of bone defects with absorbable membranes. A study on rabbits.

Self-reinforced polyglycolic acid (SR-PGA) devices were developed in the mid-eighties, applied for fixation purposes and proved to be biocompatible. In this study SR-PGA membranes (10 x 10 mm) were used to augment defects on the medial aspect of distal femoral metaphysis in 31 New Zealand rabbits. Defects of 3.5 mm were either filled with autografts or left non-grafted. In a control group, no membranes were used. The rabbits were followed up for six, 12 and 24 weeks. Radiography, histology, oxytetracycline (OTC) fluorescence labelling and microradiography were used. Defects where membranes were used, healed by new bone formation. In some cases where polyglycolic acid (PGA) membranes were not used, defects were invaded by fibrous tissue. Membranes sometimes slipped away from their positions opposite to grafted defects. This study proved that the advantage of the use of PGA membranes could be taken in augmentation of cancellous bone defects in rabbits.

Absorption↗
PubMed1994

Clinical and roentgenographic results of cementless total hip arthroplasty.

A retrospective clinical and roentgenographic review was performed on 69 consecutive cementless total hip arthroplasties that had been in situ for an average of 64.4 months (range, 57-91 months). Four patients had bilateral operations. There were 23 men and 42 women. The Lord Madreporic prosthesis (Bacneux, France) was used in 49 cases, and the Link prosthesis (Waldemar Link, Hamburg, Germany) was used in 20 cases. Preoperative diagnoses were osteoarthritis (76.8%), rheumatoid arthritis (17.4%), and miscellaneous (5.8%). At the final follow-up examination, the median hip score, assessed according to a modification of the Mayo scoring system, was 86.7 points. Seventy-eight percent of the cases had a good result, 11% were fair, and 4.7% were poor. The overall revision rate was 6.3%. No significant correlation existed between the roentgenographic and clinical findings. Subsidence of the femoral component is not a definitive hallmark of loosening in the midrange interval, that is, between 2 and 5 years. The cementless hip arthroplasty is suitable for patients with rheumatoid arthritis.

Adult↗
PubMed1994

The effect of absorbable self-reinforced polyglycolide membrane on metaphyseal bone. An experimental study on rats.

The effect of self-reinforced polyglycolide (SR-PGA) absorbable membranes on metaphyseal bone was studied in eighty-seven rats. SR-PGA membranes, 0.15 mm thick, were implanted on the femoral metaphyseal bone: on the periosteum, and directly on bone after periosteal stripping. In a control group, only periosteal stripping was performed. The rats were killed after 1, 3, 6, 12 and 24 weeks. Fibrous tissue formation around the implant, periosteal thickening and new bone formation occurred more extensively when SR-PGA membranes were implanted directly on bone after periosteal stripping. Fibrous tissue invaded the membranes. At twenty-four weeks, few fibre remnants were found embedded in a rim of fibrous tissue. No locally adverse reactions were recorded. Polyglycolide (PGA) appeared to have a positive inductive effect on new bone formation.

Absorption↗
PubMed1992

Capacitively coupled electrical field in the treatment of a leg fracture after total knee replacement.

Electrical stimulation has been used as treatment for nonunions of fractures since the early 1950s, with a reported success rate of 80-85%. We report a case of nonunion of a tibial fracture below a revised total knee prosthesis treated with a capacitively coupled electrical field. After 3 months of treatment, consolidation of this difficult fracture was evident with abundant callus formation.

Aged↗
PubMed1992

The effect of an intramedullary biodegradable self-reinforced polyglycolic acid implant on tubular bone. An experimental study on growing dogs.

The purpose of this study was to examine the effects of intramedullary self-reinforced polyglycolic acid (SR-PGA) implant to the femoral bone growth in a growing dog by using radiographic, microradiographic, oxytetracycline-fluorescence, histological, polariscopical and histomorphometric studies. Intramedullary reaming and SR-PGA implant did not cause any longitudinal overgrowth phenomenon, but resulted in a slight increase in femoral neck-angle. The bone histology showed normal features and blood cell counts were within normal limits.

Animals↗
PubMed1992

The effect of an intramedullary self-reinforced poly-L-lactide (SR-PLLA) implant on growing bone with special reference to fixation properties. An experimental study on growing rabbits.

Polylactic acid (PLA) is a synthetic biodegradable material. The self-reinforced implants made of poly-L-lactic acid (SR-PLLA) were manufactured of biodegradable polymeric matrix reinforced with fibres of the same material. The purpose of this study was to find out the effect of an intramedullary SR-PLLA implant on growing bone and its applicability to the fixation of a femoral shaft osteotomy in a growing rabbit. In seven rabbits 6 weeks of age a SR-PLLA implant 2.0 mm in diameter and 50 mm in length was introduced into the intramedullary cavity of the right femur. A proximal femoral shaft osteotomy of the right femur was made in another ten 6-weeks-old rabbits. After accurate reduction, fixation of the osteotomy was achieved with an intramedullary 2.0 mm by 50 mm SR-PLLA-rod. The follow-up times were 6 and 28 weeks. An intramedullary SR-PLLA-rod neither caused any disturbance of the bone growth nor abnormalities of the peripheral blood cell counts. Solid union of the osteotomy was seen in six weeks after fixation with SR-PLLA implant.

Animals↗