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Biomedical subjects

O Böstman

Publications and source records attributed to O Böstman.

At least 37 records · Page 2Linked to original sources
PubMed1995

Fixation of scaphoid delayed union and non-union with absorbable polyglycolide pin or Herbert screw. Consolidation and functional results.

Internal fixation with an absorbable polyglycolide pin or a Herbert screw was used to treat 34 patients with ununited and delayed union of fractures of the carpal scaphoid. The late clinical result could be reviewed in 14 patients in the polyglycolide group and 10 in the Herbert group with an average follow-up time of 68 and 58 months, respectively. The rate of union was 64% in the polyglycolide group and 60% in the Herbert group. The functional outcome was better in the Herbert group than in the polyglycolide group. A transient local abacterial tissue reaction occurred in 5 of 20 (25%) patients in the polyglycolide group. Two Herbert screws were removed due to penetration of the screw into the radial cartilage. The complication rate was relatively high with both methods. The polyglycolide pin results were unsatisfactory in this study, and thus we do not recommend their use in delayed union of and ununited scaphoid fractures.

Adolescent↗
PubMed1995

Intramedullary nailing of tibial shaft fractures.

Sixty-four displaced tibial shaft fractures were treated using intramedullary nailing, either primarily or after an attempt at conservative treatment, which consisted of closed reduction under anaesthesia and immobilisation in a long-leg plaster cast. There were 37 closed and 27 open fractures. Three patients had a fracture of both tibiae. The median time period from the intramedullary nailing of the closed solitary fractures to union was about the same after primary nailing as after delayed nailing. Although the fractures were different in these groups, it is possible that the time spent in conservative treatment before intramedullary nailing brings no additional benefits. The incidence of deep infection in open fractures after primary nailing was 1/16. The fractures, in which an acceptable position could not be maintained using conservative methods, were mainly spiral in configuration and located in the distal third or at the junction of the middle and distal thirds of the tibia.

Adult↗
PubMed1994

Restoration of tissue components after insertion of absorbable fracture fixation devices of polyglycolide through the articular surface: an experimental study in the distal rabbit femur.

Absorbable implants for fracture fixation do not require a secondary removal procedure, a fact that could make them particularly suitable for intra-articular fixation, provided the degree of regeneration of the articular surface is acceptable. To determine the restoration pattern in distal rabbit femurs after the intra-articular insertion of absorbable fixation devices, polyglycolide pins and screws were implanted through the articular surface of the intercondylar portion of the bone in adult animals. The polymer was known to have a degradation time of approximately 20 weeks. At follow-up times of 3-48 weeks, the restoration of the tissue components was examined histomorphometrically and microradiographically. The intact contralateral femur served as an internal control. The first signs of degradation of the implants were seen at 6 weeks. The mean fractional osteoid formation surface of the bone trabeculae within the sample fields showed significantly increased values until 6 weeks but thereafter approached the level of the control femur. In the 36-week and 48-week specimens, the polyglycolide had been absorbed and the intra-articular entrance of the implant channel had become filled either with firm whitish tissue resembling mature articular cartilage or with soft undifferentiated mesenchymal tissue only. Good restoration of the trabecular bone architecture corresponding to the original subchondral bone was a prerequisite for the regeneration of the articular cartilage. The causes of the dichotomous pattern of restoration could not be identified, but possibly it represented a normal biologic variation.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗
PubMed1994

Tissue-implant interface at an absorbable fracture fixation plug made of polylactide in cancellous bone of distal rabbit femur.

The tissue-implant interface at a self-reinforced poly-L-lactide (SR-PLLA) expansion plug implanted in distal rabbit femoral cancellous bone was studied histologically, histomorphometrically, and microradiographically in 35 rabbits during consolidation of a transverse transcondylar osteotomy fixed with the SR-PLLA expansion plug. The absorbable plug for internal fixation of fractures and osteotomies measured 4.5 mm in diameter and 30 mm in length and had an expandable distal locking blade system. The femoral specimens were harvested in groups of 5-10 rabbits after a follow-up time of 3, 6, 12, and 24 weeks. The intact contralateral femur served as a control. Vigorous osteogenic response to the implant was already observed at 3 weeks postoperatively, and the osteoid surface fraction at 24 weeks was still significantly higher than in the unoperated contralateral femur. Incomplete union of the osteotomy seemed to result in increased fibrous tissue formation at the tissue-implant boundary. No signs of degradation of the SR-PLLA was observed within the entire follow-up period. The number of inflammatory cells at the tissue-implant interface was low. Consequently, the short-term biocompatibility of the implant was deemed acceptable. Clinical application of the expansion plug is being planned.

Animals↗
PubMed1994

A biodegradable expansion plug for fixation of the coracoid bone block in the Bristow-Latarjet operation.

In a prospective study, 33 patients with recurrent anterior dislocation of the shoulder were treated by a modified Bristow-Latarjet operation using a biodegradable poly-L-lactide expansion plug to fix the transferred coracoid bone block. The mean follow up was 12 months. No redislocations occurred. To assess incorporation of the bone block, serial CT scans were obtained in 18 randomly selected patients and 15 showed solid fusion. The shape of the implant was not affected by degradation during the first 18 months and there were no signs of inflammatory foreign body reaction. This type of plug avoids the complications which have necessitated the removal of metal devices and is a promising new method of fixing the transferred coracoid.

Adolescent↗
PubMed1994

Shear strength of a distal rabbit femur during consolidation of an osteotomy fixed with a polylactide expansion plug.

The consolidation of a transverse transcondylar osteotomy of the distal rabbit femur, fixed with a self-reinforced polylactide expansion plug, was studied radiographically and mechanically. The peak shear force was assessed by stressing the osteotomy site to failure. The intact contralateral femur of the same rabbit served as a control. Fifteen rabbits were tested in groups of five animals with follow-up times of 6, 12 or 24 wk after fixation of the osteotomy. The absorbable plug, measuring 4.5 mm in diameter and 30 mm in length, had an expandable distal locking blade system. Thirteen osteotomies showed a radiographically solid bony union. The mean shear strength of the specimens was 3.5 MPa at 6 wk, 3.5 MPa at 12 wk and 4.3 MPa at 24 wk. The mean shear strength of the control distal femora was 3.6 MPa. In conclusion, the fixation properties of the newly developed absorbable expansion plug were deemed satisfactory in this experimental fracture model.

Animals↗
PubMed1994

Treatment of radial head fractures with absorbable polyglycolide pins: a study on the security of the fixation in 38 cases.

Between 1986 and 1992, 43 patients with a displaced Mason type II or type III fracture of the radial head were treated by open reduction and internal fixation using absorbable polyglycolide pins. Five patients were lost to the follow-up. The clinical results were reviewed in 38 patients with an average follow-up time of 27 months. There were 19 type II and 19 type III fractures. The functional results were excellent or good in 36 patients (95%). A postoperative redisplacement was seen in one patient. Use of absorbable polyglycolide pins appear to be a feasible alternative method for the treatment of displaced radial head fractures. The results were at least equal to those obtained with metallic implants, but absorbable devices need not be removed. A complication unique to the absorbable devices is a transient local abacterial tissue reaction. The rate of tissue reaction has decreased lately, and in this study no adverse reactions from the implants occurred.

Adolescent↗
PubMed1994

Economic considerations on avoiding implant removals after fracture fixation by using absorbable devices.

Pins and screws for internal fracture fixation made of absorbable polymers have been available since the latter half of the 1980s. When using these implants there is no need for a subsequent implant removal operation. During the 7-year period 1985-1991, a total of 1219 patients were treated with such absorbable fixation devices, the most common indications being displaced malleolar fractures of the ankle and fractures of the radial head. Considering the economic viewpoints, the high acquisition costs of the absorbable implants partially outweighed the benefit of avoiding all removal procedures. When all costs also for the implant removal procedure after metallic fixation were included, the average cost saved per patient by using absorbable implants in a trimalleolar fracture was FIM 2023 (4.4% of the total costs). However, the removal of metallic devices is in fact to some degree optional, and in case the metallic implants were not removed, the economic result was in favor of the metallic devices by FIM 3684 per patient. Consequently, the ultimate economic audit of the use of absorbable vs. metallic devices is linearly dependent on the actual implant removal frequency. According to the present cost analysis, the break-even point would be attained at a removal rate of 65% in trimalleolar ankle fractures, at 51% in uni-and bimalleolar fractures and at 30% in fractures of the radial head. Only at a higher removal rate the introduction of absorbable devices would be a financially more favorable alternative.

Bone Nails↗
PubMed1994

A biodegradable expansion plug for the fixation of fractures of the medial malleolus.

In a prospective study, 26 patients with a displaced fracture of the medial malleolus were treated by open reduction and internal fixation using an absorbable self-reinforced poly-L-lactide expansion plug. Twenty-one patients could be followed regularly for at least six months. The follow-up time ranged from six to 18 months. No redisplacements occurred, and the consolidation of the fractures was uneventful. There were no signs of inflammatory foreign-body reactions. This preliminary study showed the potential of the self-reinforced polylactide expansion plug in the internal fixation of cancellous bone fractures. Further clinical applications are being planned.

Adolescent↗
PubMed1994

Absorbable plugs of self-reinforced poly-L-lactic acid in the internal fixation of rabbit distal femoral osteotomies.

An absorbable plug for the internal fixation of fractures and osteotomies, measuring 4.5 mm in diameter and 30 mm in length, was constructed of poly-L-lactide using a self-reinforcing fibers-in-matrix manufacturing technique. To increase the rotational stability and grip of the device, the plug has deployable distal fins. The plug was used in the fixation of a transverse distal femoral osteotomy in 20 rabbits. The consolidation of the osteotomy was investigated histologically, histomorphometrically, and microradiographically in groups of five rabbits observed for three, six, 12, or 24 weeks. Fifteen osteotomies showed bony union. In five rabbits, no bridging trabeculae across the osteotomy had developed, but these rabbits belonged to the groups with the shortest follow-up times of three or six weeks. No mechanical failures of the plugs were encountered, and the short-term biocompatibility of the implant was excellent. Future clinical applications are planned.

Animals↗
PubMed1993

Intraosseous cellular response to biodegradable fracture fixation screws made of polyglycolide or polylactide.

As biodegradable pins and screws have increasingly been used in the internal fixation of fractures, sterile inflammatory reactions have occasionally occurred. The aim of the present experimental study was to assess the cellular response within cancellous bone to biodegradable polyester screws. In 45 rabbis a transverse distal femoral osteotomy was fixed with a 4.5 x 30 mm screw made either of polyglycolide (PGA, in 20 rabbits) or polylactide (PLA, in 25 rabbits). The follow-up times were 3, 6, 12, 36 or 48 weeks. The time-related and spatial characteristics of the cellular response were examined histomorphometrically using standardised sample fields under polarised-light microscopy. Polymorphonuclear granulocytes and mononuclear round cells were scarce in all follow-up groups. The occurrence of phagocytic cells (mononuclear macrophages and foreign-body giant cells) was highest in the PGA-fixed 12-week specimens. The giant cells seemed to adhere to the implant surface at an early stage, whereas the ultimate digestion and clearing of the decomposing polymeric material later on were performed by macrophages invading the implant body. No PGA was left in the 36-week specimens, while the gross geometry of the PLA screws was still intact at 48 weeks. In conclusion, the inflammatory response to these polymers was quite mild. Thus it seems probable that some other additional factors must influence the occurrence of the clinical inflammatory reactions.

Animals↗
PubMed1993

The integrity of intervertebral disks after operative treatment of thoracolumbar fractures.

This study presents the results of magnetic resonance imaging (MRI) follow-up studies on 14 patients with unstable fractures of T12 or L1. Internal fixation was performed with Harrington rods in eight patients and with transpedicular fixation in six patients. Sixteen intervertebral disks adjacent to the fractured vertebral body in 11 patients showed decreased signal intensity in T2-weighted images. None of the uninjured intervertebral disks showed any detectable signal decrease in T2-weighted images. Temporary fixation of several healthy motion segments of thoracolumbar spine, as is necessary with Harrington instrumentation for 11 months, on average, does not seem to result in an intervertebral disk degeneration detectable on MRI in the patients within a follow-up period of two years.

Adolescent↗
PubMed1993

A new approach to the internal fixation of unstable pelvic fractures.

Eighteen patients with horizontally or vertically unstable pelvic fractures were operated on with a new intrapelvic technique. There were 11 horizontally unstable and seven vertically unstable pelvic ring fractures. The fractures were exposed through a low Pfannenstiel or lower midline incision combined with an incision at the iliac crest. This is referred to as the ilioanterior approach. At the operation, all lesions in the symphysis, rami, and in the sacroiliac region were reduced and fixed with reconstruction plates and screws. No intraoperative complications ensued. The average intraoperative blood loss was 930 ml and the operation time averaged two and one-half hours. The obtained reduction was maintained in all but one sacral fracture. All fractures united. The functional recovery was uneventful in all the patients. The good results obtained in this relatively small series encourage further development of operative techniques in unstable pelvic fractures.

Adolescent↗
PubMed1993

Firearm injuries in Finland 1985-1989.

Over a 5-year period 1985-1989, a total of 1,268 persons, 5.1 cases per 100,000 person-years, required hospital treatment for injuries caused by firearms in Finland. During the same period 1,295 persons died on the scene of the shooting or during transport to hospital. Among the 1,268 patients admitted alive, the principal modes of the shooting incident were accidental shooting in 57%, suicidal attempt in 20% and assault in 13%. The male:female ratio was 11:1. The median age of the patients was 31 years. The anatomical distribution of the injuries was as follows: skull or face in 36%, chest or abdomen in 17% and extremities in 47%. The mean duration of the hospital stay was 13 days. In all, 16,506 hospital days were required. Of the 1,268 patients 141 died in hospital. The hospital mortality was 104/255 in suicidal shootings, 26/158 in assaults but only 9/725 in accidents. This study showed that firearm injuries cannot be considered a negligible medical problem in Finland.

Adult↗
PubMed1992

[Absorbable rods and screws: a new method of fixation for fractures of the olecranon].

Between April 1986 and July 1990 fractures of the olecranon in 41 adult patients were treated by fixation with absorbable rods (20 patients) and screws (21 patients) of self-reinforced polyglycolide (SR-PGA), 3.2 mm in diameter and 20-70 mm in length. Patients were followed up for a mean time of 2 years 7 months (range 1 year to 4 years 6 months). After reduction of the fracture, channels were drilled from the proximal fragment through the cortex of the distal fragment and the fractures were fixed with absorbable rods or screws. By one year from follow-up maintenance of an anatomical reduction of the fracture was seen in 34 patients. Failure of fixation requiring a second operation occurred in 2 cases. In all cases functional recovery was at least satisfactory. Sinus formation as a sign of transient tissue reaction was observed in 3 cases, but did not influence the healing of the fractures or the functional recovery. The results in patients treated with rods or screws was similar. Absorbable screws combined with small rods and absorbable sutures allow treatment of +ore severe fractures of the olecranon than do rods alone.

Adult↗
PubMed1992

Self-reinforced absorbable screws in the fixation of displaced ankle fractures: a prospective clinical study of 152 patients.

The series consisted of 152 patients with ankle fractures treated between May 1987 and August 1989 using absorbable screws of self-reinforced polyglycolide 3.4 mm in inner diameter and 25-70 mm in length. The mean follow-up time was 2 years, 5 months (range, 1 year, 7 months-3 years, 10 months). After open reduction, a channel was drilled through the fracture surfaces and the fragments were fixed with one absorbable screw or screws. A plaster cast was used postoperatively. At 1-year follow-up observation, the radiographical result was anatomical in 93.3% of 104 patients with unimalleolar and bimalleolar ankle fractures (Weber A or B) and in 80.5% of 41 severe ankle fractures. Seven patients were unavailable for follow-up observation. Two reoperations were performed because of primary or secondary failure of fixation. In all unimalleolar and bimalleolar fractures and in 95.1% of severe ankle fractures the functional recovery score was at least satisfactory. Sinus formation as a sign of tissue reaction was observed in 10 patients 2-6 months postoperatively, but this did not influence the healing of the fracture or the functional recovery. This report is the first extensive publication on the clinical use of absorbable screws.

Activities of Daily Living↗
PubMed1992

Mechanical failures of internal fixation in T and Y fractures of the distal humerus.

To evaluate the factors resulting in mechanical failures of internal fixation of distal T-type and Y-type humeral fractures, we reviewed the clinical course and final results in 61 consecutive cases treated with AO-ASIF internal fixation devices. The patients were followed for at least 2 years (range, 2-11 years). Mechanical failure occurred in 18 cases (29.5%). In 12 patients this resulted from an unstable fixation. Severe osteoporosis was present in four patients. In two patients no specific causative factor could be detected. A second osteosynthesis was undertaken in five patients, and four additional patients were later operated on for nonunion. The functional outcome after these mechanical failures was, unexpectedly, poor in only 6 of the 18 patients. In spite of this comforting finding, the conclusion is that to minimize the failure rate in the management of these demanding fractures strict adherence to the correct technical fixation principles is mandatory, and when the bone is very osteoporotic a nonsurgical approach seems advisable.

Adolescent↗