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Biomedical subjects

O M Böstman

Publications and source records attributed to O M Böstman.

At least 19 recordsLinked to original sources
PubMed2005

Tissue restoration after resorption of polyglycolide and poly-laevo-lactic acid screws.

Despite worldwide clinical use of bio-absorbable devices for internal fixation in orthopaedic surgery, the degradation behaviour and tissue replacement of these implants are not fully understood. In a long-term experimental study, we have determined the patterns of tissue restoration 36 and 54 months after implantation of polyglycolic acid and poly-laevo-lactic acid screws in the distal femur of the rabbit. After 36 months in the polyglycolic acid group the specimens showed no remaining polymer and loose connective tissue occupied 80% of the screw track. Tissue restoration remained poor at 54 months, the amounts of trabecular bone and haematopoietic elements being significantly lower than those in the intact control group. The amount of trabecular bone within the screw track at 54 months in the polyglycolic acid group was less than in the empty drill holes (p = 0.04). In the poly-laevo-lactic acid group, polymeric material was present in abundance after 54 months, occupying 60% of the cross-section of the core area of the screw track. When using absorbable internal fixation implants we should recognise that the degradation of the devices will probably not be accompanied by the restoration of normal trabecular bone.

Absorbable Implants↗
PubMed2000

Population based epidemiologic and morphologic study of femoral shaft fractures.

The epidemiologic and morphologic features of all femoral shaft fractures in skeletally mature patients treated during a 10-year period in a semi-urban county were analyzed. Among an average adult population of 202,592 residents, 192 people sustained 201 traumatic femoral shaft fractures during the study period. The incidence was 9.9 fractures per 100,000 person-years. The highest age and gender specific incidences were seen in males from 15 to 24 years of age and in females 75 years of age or older. Seventy-five percent (151) of the fractures were the result of a high-energy trauma, 131 of which occurred in road traffic accidents. Unexpectedly, there were 50 low-energy fractures. Fractures of the middle 1/3 of the diaphysis were 79%. The majority, 155 (77%), of all fractures were transverse, oblique, or oblique transverse. Regarding the degree of comminution, the Winquist and Hansen Grade 0 (noncomminuted) fracture was the most common. Forty-eight percent of fractures were AO Type A, 39% were Type B, and 13% were Type C fractures. Of the 25 open fractures, 14 were Gustilo Type II. All six Type III open injuries were Type IIIA. Based on the data from the current study, most of the femoral fractures in this community might be treated adequately with conventional intramedullary nails, rather than using interlocking nails, provided the stability of fixation and fracture alignment can be maintained. Preventive measures against femoral shaft fractures should focus on protection of automobile drivers, especially young men, and on effective treatment of osteoporosis in elderly women.

Adolescent↗
PubMed2000

Adverse tissue reactions to bioabsorbable fixation devices.

Among 2528 patients operated on using pins, rods, bolts, and screws made of polyglycolic acid or polylactic acid, 108 (4.3%) were affected by a clinically significant local inflammatory, sterile tissue reaction. The three most common indications for the use of these fixation devices were a displaced malleolar fracture, a chevron osteotomy for hallux valgus, and a displaced fracture of the radial head. In 107 patients, the reaction was elicited by a polyglycolic acid implant, and in one patient by a polylactic acid implant. The incidences were 5.3% (107 of 2037) and 0.2% (one of 491), respectively. The adverse tissue responses to polyglycolic acid were seen 11 weeks after the operation, on average, whereas the reaction to polylactic acid occurred 4.3 years after fixation of an ankle fracture. The mild reactions consisted of a painful erythematous papule of a few weeks' duration. Those of medium severity had a sinus that discharged remnants of the implant for up to 6 months. In the patients affected by severe reactions, extensive osteolytic lesions developed at the implant tracks. The histopathologic picture was that of a nonspecific foreign body reaction. In four patients with vigorous reactions, an arthrodesis of the wrist or ankle later was necessary because of severe osteoarthritis. Several markers of increased risk of the occurrence of a foreign body reaction were found. These included a poorly vascularized bone section such as scaphoid, use of a quinone dye as an additive in the polymer, and an implant geometry with large surface area (screw versus pin or rod). For polyglycolic acid implants, the risk of an adverse tissue response in a given clinical situation can be estimated from the findings of this study. For slow degrading polymers like polylactic acid, however, the ultimate biocompatibility still is unsettled, and additional clinical research with long followup is required.

Absorbable Implants↗
PubMed1998

Osteoarthritis of the ankle after foreign-body reaction to absorbable pins and screws: a three- to nine-year follow-up study.

Between 1985 and 1994, 1223 patients with malleolar fractures of the ankle were treated by open reduction and internal fixation with absorbable pins and screws, of whom 74 (6.1%) had an obvious inflammatory foreign-body reaction to the implants. Of these 74, ten later developed moderate to severe osteoarthritis of the ankle despite no evidence of incongruity of the articular surface. The implants used in these patients were made from polyglycolide, polylactide or glycolide-lactide copolymer. The joint damage seemed to be due to polymeric debris entering the articular cavity through an osteolytic extension of an implant track. The ten patients had a long clinical course which included a vigorous local foreign-body reaction, synovial irritation and subsequent degeneration. At a follow-up of three to nine years, ankle arthrodesis had been necessary in two patients and is being considered for another two. The incidence of these changes in the whole series was 0.8%, which is not high, but awareness of this possible late complication is essential.

Absorption↗
PubMed1997

MR imaging of biodegradable polylevolactide osteosynthesis devices in the ankle.

OBJECTIVE: To assess the feasibility of magnetic resonance (MR) imaging in the postoperative follow-up after internal fracture fixation using biodegradable polylevolactide (PLLA) plugs and to investigate the MR characteristics of these devices. STUDY DESIGN AND METHODS: MR findings in ten patients with displaced malleolar fractures treated by internal fixation using absorbable PLLA plugs were evaluated after three different postoperative periods. The average postoperative follow-up time was thirty months for four patients, forty-two months for another four patients, and fifty-one months for the remaining two patients. RESULTS: On T1-weighted coronal images, the geometry of the PLLA plug was clearly visible in all cases, without signs of fatigue failure or absorption. The host-to-tissue area between the deployed two fins of the plug showed higher signal intensity than the surrounding cancellous bone on fat-saturated proton density (PD) and turbo inversion recovery (tIR) images. This area had signal intensity similar to articular cartilage on T1-weighted coronal images. In none of the cases could any fluid accumulation be seen around the plug. In all ten cases, a thin rim with signal intensity similar to the area between the deployed fins was detected around the PLLA plug on fat-saturated axial PD images. On fat-saturated T2 and tIR sequences, this rim was less clearly detectable in all cases. No differences in the signal intensity or geometry of the PLLA plug on the MR images emerged between the three patient groups with mean follow-ups of thirty, forty-two, and fifty-one months. No artifacts produced by the implants were seen on any of the MR images. A biopsy specimen obtained at a reoperation necessary seventeen months postoperatively showed no signs of degradation of the PLLA plug. CONCLUSIONS: MR imaging can visualize PLLA implants within bone. It also shows, without artifacts, the tissue interaction between the artificial biodegradable material and bone tissue in humans.

Absorption↗
PubMed1996

Metallic or absorbable fracture fixation devices. A cost minimization analysis.

Absorbable polyester pins and screws for the internal fixation of small fragment fractures have been commercially available for several years. The main advantage of these devices is that no implant removal procedures are required, which could result in financial savings. The current cost analysis, which included costs of medical care plus costs of lost time from work, was based on 994 fracture patients treated with absorbable internal fixation devices and 1173 patients operated on using conventional metallic devices. The fracture types studied were uni- and trimalleolar fractures of the ankle, fractures of the olecranon, and metacarpal fractures. When the costs for an implant removal procedure after metallic fixation were included, the average cost saved per patient by using absorbable implants varied from $410 in fractures of the olecranon to $903 in unimalleolar fractures. However, hardware removals often are optional. According to the results of this cost analysis, the break even point is attained at a removal rate of 19% for metacarpal fractures, 21% for unimalleolar fractures, 46% for fractures of the olecranon, and 54% for trimalleolar fractures. Only at a higher removal rate would the use of absorbable devices, with their current prices, be a financially more favorable alternative than the use of metallic ones.

Adolescent↗
PubMed1995

Reduction of bone retropulsed into the spinal canal in thoracolumbar vertebral body compression burst fractures. A prospective randomized comparative study between Harrington rods and two transpedicular devices.

STUDY DESIGN: This was a prospective, randomized study. OBJECTIVE: To compare the ability of three methods of internal fixation (Harrington rods, AO internal fixator, posterior segmental fixator) to obtain reduction of intracanal fragments in thoracolumbar vertebral compression burst fractures. SUMMARY OF BACKGROUND DATA: Sixty-seven acute thoracolumbar compression burst fractures of T12 or L1 were randomized into three groups that were treated using one of the three methods. Reduction was accomplished indirectly by distraction applied using the fixation device. METHODS: The spinal canal encroachment was calculated as a percentage of the estimated pre-injury value from serial transverse computed tomographic scans obtained on admission and immediately after surgery. RESULTS: The median preoperative sagittal encroachment of the spinal canal was 37% (range, 0-90%) of the normal diameter. All three methods of internal fixation produced a spinal canal clearance provided that the patient was operated on within 4 days after trauma. The median postoperative encroachment varied from 13% (range, 0-37%) to 22% (range, 0-37%), the best reduction being attained using Harrington rods and the poorest with the posterior segmental fixator. There was a suggestive statistical significance between these two. CONCLUSION: The differences in postoperative spinal canal encroachment and ability to obtain spinal canal clearance observed between the devices studied were small. There seems to be no reason to base the choice of the operative method in thoracolumbar fractures on any hypothetical differences in reductive power between Harrington rods and the AO internal fixator.

Adolescent↗
PubMed1995

Clinical biocompatibility and degradation of polylevolactide screws in the ankle.

The clinical biocompatibility and degradation behavior of absorbable fracture fixation devices are still incompletely known in humans. Fifty-one patients with displaced fracture of the ankle treated by open reduction and internal fixation with absorbable screws made of polylevolactide were seen in followup for at least 3 years. The mean duration of followup time was 52 months. The tissue tolerance and degradation of the devices were studied clinically and radiographically using computed tomographic scans. In addition, biopsy specimens for histologic examination were taken in 5 patients. The screws were clinically effective: An accurate position of the fragments was maintained until union in 50 patients. A mild transient subcutaneous late foreign body reaction occurred in 1 patient 22 months after fixation of the fracture. Despite radiographic evidence of an advancing degradation of the implants, biopsy specimens taken 45 months after the original operation still showed consistent areas of polylactide in the tissues. In 3 patients, a disturbing palpable subcutaneous screw head had to be removed. The incidence of foreign body reactions to polylevolactide screws in the ankle seems to be low, but the duration of the degradation process of the polymer in human tissues is considerably longer than has been anticipated.

Adult↗
PubMed1995

Body-weight related to loss of reduction of fractures of the distal tibia and ankle.

A series of 3061 patients with fracture of the distal tibia or ankle was studied for a possible link between overweight and failed reduction. The relative body-weight was recorded as the preoperative self-reported body mass index (BMI) of each patient. There were 109 patients (3.6%) with failure of internal fixation or of closed reduction severe enough to necessitate refixation or corrective osteotomy. The mean BMI in all age- and gender-specific groups studied was found to be significantly higher in patients with failed reduction than in those with an uneventful course (p < 0.01). The relative risk of loss of reduction for patients with a BMI greater than 1SD above the BMI of the corresponding age and gender group of the general population was 3.72 for distal tibial fractures and 3.04 for ankle fractures. Overweight should be recognised as a significant factor in predicting a complicated course after a fracture of the lower leg. Awareness of the increased risk of loss of reduction in overweight patients is important in all phases of management.

Adult↗
PubMed1994

Body mass index of patients with elbow and ankle fractures requiring surgical treatment.

To determine whether being overweight is a predisposing factor for some common fracture types caused by stumbling, slipping, and low-energy falls, the body mass index (BMI) of 4012 adult patients with acute extremity fractures requiring surgical treatment was compared with the age-specific and sex-specific BMI values obtained from a general population sample. The cross-sectional study included 317 patients with displaced fractures of the elbow joint (distal humerus, olecranon, or radial head) and 3695 patients with displaced malleolar fractures of the ankle. To delineate possible differences in BMI, 95% confidence intervals (CI) for the mean BMI values of age- and sex-specific subgroups were calculated. With the exception of two subgroups with elbow fractures, men aged 20-29 years and women aged 60-69 years, the fracture patients were found to have a higher mean BMI than the general population. Major contrasts emerged in middle-aged men with ankle fractures, the 95% CI for the mean BMI in the age group 50-59 years being 27.4-28.2 kg/m2 versus 25.7-26.3 kg/m2 in the general population. The conclusion of the study was that an increased body mass index was descriptive of patients with displaced fractures at the elbow and the ankle, and that overweight and obesity can be regarded as predisposing factors to these injuries.

Adult↗
PubMed1994

Prevalence of obesity among patients admitted for elective orthopaedic surgery.

The aim of this work was to test the hypothesis that obesity is more common among patients requiring elective orthopaedic surgery than in the general population. A cross-sectional survey was carried out on 2673 consecutive patients admitted from the waiting list for four common types of operation: removal of lumbar intevertebral disc herniation, total hip replacement, elective knee arthroscopy or total knee replacement. Patients with primarily inflammatory joint disease were excluded. The immediate preoperative relative body weight, calculated as body mass index (BMI), of the patients was compared with data available on a general population sample of 44,034 people. Obesity was defined as BMI greater than the BMI + one standard deviation of the corresponding age and sex category of the general population. By these criteria, 256 patients (27%) with lumbar intervertebral disc herniation, 192 (24%) with total hip replacement, 135 (22%) with knee arthroscopy and 80 (27%) with knee replacement were obese, whereas the proportion in the general population was 16%. A major difference with the general population emerged in young patients of both sexes operated on for lumbar disc herniation and in women admitted for knee arthroscopy. The mean BMI of men aged 20 to 49 years subjected to knee arthroscopy did not differ from the general population. It was concluded that overweight people seem to be strongly over-represented among the patients requiring common orthopaedic surgical procedures.

Adult↗
PubMed1993

Body mass index and height in patients requiring surgery for lumbar intervertebral disc herniation.

The immediate preoperative body mass index and standing body height of 1128 patients who underwent surgery for lumbar intervertebral disc herniation were compared in a cross-sectional study with the corresponding values obtained from a general population sample. The material was divided into sex- and age-specific subgroups. To delineate possible differences, the 99% confidence intervals for the anthropometric mean values were constructed instead of hypothesis testing. With the exception of the oldest age group, from 50 to 59 years, the patients who underwent surgery for a disc herniation were more obese and taller than the population on average in all other sex- and age-specific subgroups. The major contrast emerged in women aged 20-29 years, in whom the 99% confidence interval for the mean body mass index of the patients undergoing surgery on was 25.1-27.3 kg/m2 versus 22.3-23.1 kg/m2 in the general population. In patients aged 20-39 years the mean body mass index was increased also when the body height of the patients was less than the mean value of the general population samples. Both an increased body mass index and a tall stature seem to have a clear association with those severe lumbar intervertebral disc herniations that require operative treatment.

Adult↗
PubMed1993

Distal tibiofibular synostosis after malleolar fractures treated using absorbable implants.

Three patients (3.8%) of 80 with displaced malleolar fractures treated by open reduction and internal fixation using absorbable polyglycolide rods were found to have developed distal tibiofibular synostosis. To assess the general incidence of this complication, the serial radiographs of 150 patients with an identical distribution of the initial fracture severity treated with AO-ASIF implants were examined for comparison. Among these, no cases of tibiofibular synostosis were found. The difference (P = .04) in incidence was postulated to be due to an osteogenic potential of the absorbable polymeric material, suggested previously in experimental studies. This study included fractures of the lateral malleolus and bimalleolar fractures, but patients with a disruption of the inferior tibiofibular syndesmosis causing tibiofibular diastasis on admission were excluded. The synostoses occurred in middle-aged, sedentary people, and no active measures were necessary because of the mild subjective symptoms of these patients. Previously, posttraumatic distal tibiofibular synostosis has been recorded as an uncommon late complication of severe ankle fractures with tibiofibular diastasis requiring transsyndesmotic fixation, but it has not been reported to occur after malleolar fractures of the kind surveyed in this study.

Adolescent↗
PubMed1992

Intense granulomatous inflammatory lesions associated with absorbable internal fixation devices made of polyglycolide in ankle fractures.

Since absorbable internal fracture fixation devices made of polyglycolide have been increasingly used clinically, a peculiar type of complication has emerged. After an initially uneventful course, a local nonbacterial inflammatory reaction appears two to four months after the operation, resulting in a copiously discharging sinus on the skin. A series of 286 patients with unimalleolar or bimalleolar fractures were treated by open reduction and internal fixation using cylindrical rods made of polyglycolide. Among these there occurred 18 nonbacterial inflammatory tissue responses (6.3% of the total) requiring surgical drainage. Six patients had an intense reaction necessitating repeated surgical measures and inpatient management. The hospital stay of these patients averaged 18 days. The mean duration of the discharge from the lesions was 10.8 weeks. Microscopic examination of biopsy specimens showed a nonspecific foreign-body reaction composed mainly of neutrophilic polymorphonuclear leukocytes and foreign-body giant cells phagocytizing the polymer debris left behind by the decomposing implants. On roentgenograms, osteolytic increase of the diameter of the implant channels was observed, but the bony union of the fracture seemed not to be disturbed. Thus the factors increasing the susceptibility of some individuals to this complication remain unknown.

Ankle Injuries↗