Search

Studies on the effects of the pulse waveform used in electrical muscle stimulation on the activations and perceived discomfort of the waveform have been mainly executed on limb muscles with variable results, however, knowledge of these effects on facial muscles is currently lacking. We studied two waveforms, square wave and sinusoidal wavelet, for the activation of the frontalis muscle in 9 individuals with unresolved facial nerve palsy. Both waveforms produced a movement that was greater in amplitude compared with the maximal voluntary movement of the affected side in 8 participants and at least as great as the healthy side's maximal voluntary movement in 4 participants. Both waveforms were equally successful in producing movements, and there was no significant difference in perceived discomfort ratings between the two waveforms. These findings will be useful for the future development of neuroprosthetic applications for reanimating facial muscles using electrical stimulation. Trial registration: ClinicalTrials.gov NCT03496025, registration date March 19, 2018.

Efficient, comfortable, yet affordable personal protective equipment (PPE) is needed to decrease the high incidence of allergic contact dermatitis arising from epoxy resin systems (ERSs) in industrial countries. The aim of this study was to find affordable, user-friendly glove and clothing materials that provide adequate skin protection against splashes and during the short contact with ERS that often occurs before full cure. We studied the penetration of epoxy resin and diamine hardeners through 12 glove or clothing materials using a newly developed test method. The tests were carried out with two ERS test mixtures that had a high content of epoxy resin and frequently used diamine hardeners of different molar masses. A drop (50 µl) of test mixture was placed on the outer surface of the glove/clothing material, which had a piece of Fixomull tape or Harmony protection sheet attached to the inner surface as the collection medium. The test times were 10 and 30 min. The collecting material was removed after the test was finished and immersed into acetone. The amounts of diglycidyl ether of bisphenol A (DGEBA), isophorone diamine (IPDA), and m-xylylenediamine (XDA) in the acetone solution were determined by gas chromatography with mass spectrometric detection. The limit for acceptable penetration of XDA, IPDA, and DGEBA through glove materials was set at 2 µg cm(-2). Penetration through the glove materials was 1.4 µg cm(-2) or less. The three tested chemical protective gloves showed no detectable penetration (<0.5 µg cm(-2)). Several affordable glove and clothing materials were found to provide adequate protection during short contact with ERS, in the form of, for example, disposable gloves or clothing materials suitable for aprons and as additional protective layers on the most exposed parts of clothing, such as the front of the legs and thighs and under the forearms. Every ERS combination in use should be tested separately to find the best skin protection material, and this can be done by using this simple test method., (© The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.)

The causal relationship between inhalation exposure to methylenediphenyl diisocyanate (MDI) and the risk of occupational asthma is well known, but the role of dermal exposure and dermal uptake of MDI in this process is still unclear. The aims of this study were to measure dermal exposure to and the dermal uptake of MDI among workers (n=24) who regularly handle MDI-urethanes. Dermal exposure was measured by the tape-strip technique from four sites on the dominant hand and arm. The workers with the highest exposure (n=5) were biomonitored immediately after their work shift, in the evening and the next morning, using urinary 4,4´methylenedianiline (MDA) as a marker. Dermal uptake was evaluated by comparing workers' MDA excretions both when they were equipped with respiratory protective devices (RPDs) and when they did not use them. The measured amounts of MDI on their hands varied from below 0.1 to 17 μg/10 cm(2) during the test. MDI concentrations were in the range of 0.08 to 27 μg m(-3) in the breathing zone outside the RPDs. MDA concentrations varied from 0.1 to 0.2 μmol mol(-1) creatinine during the test period. The decreasing effect of RPDs on inhalation exposure was absent in the next morning urine samples; this excretion pattern might be an indication of dermal uptake of MDI., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Background: The optimal treatment of acute, complete dislocation of the acromioclavicular joint (ACJ) is still unresolved., Purpose: To determine the difference between operative and nonoperative treatment in acute Rockwood types III and V ACJ dislocation., Study Design: Randomized controlled trial; Level of evidence, 2., Methods: In the operative treatment group, the ACJ was reduced and fixed with 2 transarticular Kirschner wires and ACJ ligament suturing. The Kirschner wires were extracted after 6 weeks. Nonoperatively treated patients received a reduction splint for 4 weeks. At the 18- to 20-year follow-up, the Constant, University of California at Los Angeles Shoulder Rating Scale (UCLA), Larsen, and Simple Shoulder Test (SST) scores were obtained, and clinical and radiographic examinations of both shoulders were performed., Results: Twenty-five of 35 potential patients were examined at the 18- to 20-year follow-up. There were 11 patients with Rockwood type III and 14 with type V dislocations. Delayed surgical treatment for ACJ was used in 2 patients during follow-up: 1 in the operatively treated group and 1 in the nonoperatively treated group. Clinically, ACJs were statistically significantly less prominent or unstable in the operative group than in the nonoperative group (normal/prominent/unstable: 9/4/3 and 0/6/3, respectively; P = .02) and in the operative type III (P = .03) but not type V dislocation groups. In operatively and nonoperatively treated patients, the mean Constant scores were 83 and 85, UCLA scores 25 and 27, Larsen scores 11 and 11, and SST scores 11 and 12 at follow-up, respectively. There were no statistically significant differences in type III and type V dislocations. In the radiographic analysis, the ACJ was wider in the nonoperative than the operative group (8.3 vs 3.4 mm; P = .004), and in the type V dislocations (nonoperative vs operative: 8.5 vs 2.4 mm; P = .007). There was no statistically significant difference between study groups in the elevation of the lateral end of the clavicle. Both groups showed equal levels of radiologic signs of ACJ osteoarthritis and calcification of the coracoclavicular ligaments., Conclusion: Nonoperative treatment was shown to produce more prominent or unstable and radiographically wider ACJs than was operative treatment, but clinical results were equally good in the study groups at 18- to 20-year follow-up. Both treatment methods showed statistically significant radiographic elevations of the lateral clavicle when compared with a noninjured ACJ.

Diphenylmethane diisocyanate (MDI) is a sensitizing chemical that can cause allergic contact dermatitis and asthma. Protective gloves and clothing are necessary to prevent skin exposure. Breakthrough times are used for the selection of chemical protective gloves and clothing. In the EN 374-3:2003 European standard, breakthrough time is defined as the time in which the permeation reaches the rate of 1.0 µg min(-1) cm(-2) through the material. Such breakthrough times do not necessarily represent safe limits for sensitizing chemicals. We studied the permeation of 4,4'-MDI through eight glove materials and one clothing material. The test method was derived from the EN 374-3 and ASTM F 739 standards. All measured permeation rates were below 0.1 µg min(-1) cm(-2), and thus, the breakthrough times for all the tested materials were over 480min, when the definitions of EN 374-3 and ASTM F 739 for the breakthrough time were used. Based on the sensitizing capacity of MDI, we concluded that a cumulative permeation of 1.0 µg cm(-2) should be used as the end point of the breakthrough time determination for materials used for protection against direct contact with MDI. Using this criterion for the breakthrough time, seven tested materials were permeated in <480min (range: 23-406min). Affordable chemical protective glove materials that had a breakthrough time of over 75min were natural rubber, thick polyvinylchloride, neoprene-natural rubber, and thin and thick nitrile rubber. We suggest that the current definitions of breakthrough times in the standard requirements for protective materials should be critically evaluated as regards MDI and other sensitizing chemicals, or chemicals highly toxic via the skin., (© The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.)

Objectives: Since there are few data on the effects of metalworking in populations representing a variety of metal companies or on dose-response relationships concerning metalworking, this study investigated the relationship between occupational exposures in machine shops and the occurrence of upper and lower respiratory symptoms, asthma, and chronic bronchitis., Methods: A cross-sectional study of 726 male machine workers and 84 male office workers from 64 companies was conducted in southern Finland. All of the participants filled out a questionnaire, and aerosol measurements were performed in 57 companies., Results: Exposure to metalworking fluids (MWF) showed a greater risk [odds ratio (OR)>or=2) for upper-airway symptoms, cough, breathlessness, and current asthma than exposures in office work did. Exposure to aerosol levels above the median (>or=0.17 mg/m3 in the general workshop air) was related to an increased risk (OR>or=2) of nasal and throat symptoms, cough, wheezing, breathlessness, chronic bronchitis, and current asthma. Machine workers with a job history of >or=15 years experienced increased throat symptoms, cough, and chronic bronchitis., Conclusions: This large study representing machine shops in southern Finland showed that machine workers experience increased nasal and throat symptoms, cough, wheezing, breathlessness, and asthma even in environments with exposure levels below the current occupational exposure limit for oil mists. The study suggests that improving machine shop environments could benefit the health of this workforce. It also suggests that it is time to consider reducing the current Finnish occupational exposure limit for oil mist or introducing the use of other health-relevant indicators of exposure.

Self-reinforced polylactide-polyglycolide (80/20) composite rods, 2 mm in diameter and 36 mm in length, were implanted into the dorsal subcutaneous tissue of 20 rabbits. Osteotomies of the distal femur were fixed with these rods (2x15 mm) in the rabbits. The follow-up times varied from 3 to 104 weeks. After sacrifice, three-point bending and shear tests and molecular weight measurements were performed for subcutaneously placed rods. Radiological, histological, microradiographic, oxytetracycline-fluorescence, and histomorphometrical studies of the osteotomized and intact control femora were performed. After 6 weeks the mechanical properties had decreased significantly, but osteotomies had healed uneventfully. The present investigation showed that the mechanical strength and fixation properties of SR-Polylactide-glycolide (80/20) rods are suitable for fixation of cancellous bone osteotomies in rabbits provided that the operative technique is correct. The present article is the first report on the application of these rods for fixation of cancellous bone osteotomies.

Glyoxal is a dialdehyde that is used as a disinfectant in health care and dentistry work. Allergic contact dermatitis from glyoxal has been described in these occupations. We analysed our patient data from 1998 to 2004 for allergic reactions to glyoxal. 20 patients had allergic reactions to glyoxal on patch testing. 5 of these patients worked in dentistry and 4 of them had present exposure to glyoxal. 9 patients were machinists without obvious exposure to glyoxal. A grinder with work-related facial dermatitis is described in detail. The chemical analysis of air samples from his workplace revealed 9.4-21 microg/m3 glyoxal. Glyoxal was also present in the used metal-working fluid, and apparently it had been formed during grinding. The remaining 6 patients worked in miscellaneous occupations and had no present exposure to glyoxal. Glyoxal is irritant on patch testing. Especially, solitary reactions to glyoxal 10% in aq. may be false-positive irritant reactions. 9 (45%) of our patients reacted to formaldehyde or glutaraldehyde. Glyoxal is an important allergen in dentistry and medical care, and we recommend it to be added to the antimicrobial patch test series. It also seems to be a 'hidden' allergen in the metal industry.

Disinfectants may cause adverse effects directly on the skin or systemically by permeating through the skin. In this study breakthrough times were measured for surgical gloves with chemicals which are commonly used in healthcare. Classical methods of analytical chemistry were tailored for the permeation tests, which were carried out according to the European standard EN 374 and the American standard ASTM F739. An exception to the EN 374 standard was made by using a 4 h testing time instead of 8 h. The gloves did not exhibit permeation of potassium hydroxide (45%), sodium hypochlorite (13%) or hydrogen peroxide (30%). Furthermore, neither glutaraldehyde (2%) nor chlorhexidine digluconate (4%) in the commercial disinfectant solutions studied exhibited permeation. Slight permeation of peracetic acid (0.35%) and acetic acid (4%) from a disinfectant agent was observed through single layered natural rubber materials. Clear evidence of formaldehyde permeation was detected through single layered natural rubber gloves, where the ASTM breakthrough times were 17-67 min, but the permeation rates were not high enough for breakthrough to have occurred according to the EN standard. The gloves in this study which offered most protection from chemical permeation were the chloroprene gloves and the thick double layered natural rubber gloves.

Standard test methods ASTM F739 and EN 374 were compared by assessing the permeation of 70% isopropyl alcohol (2-propanol) through seven brands of surgical gloves. The two standards differ in the flow rates of the collection medium and in the chemical permeation rate at which the breakthrough time (BTT) is detected, the EN detection level being 10 times higher than the permeation rate used by ASTM. In a departure from the EN standard method, a 4 h testing time was used instead of 8 h. All of the tested gloves were from the same manufacturer and were made from either natural rubber (NR) (six brands) or chloroprene rubber (CR) (one brand). Two of the NR glove brands were double layered. For the thin NR gloves (0.22, 0.28 and 0.27 mm) the permeation rates were higher throughout the tests with a flow rate of 474 ml/min (EN) of the collection medium (nitrogen) compared with the permeation rates obtained with a flow rate of 52 ml/min (ASTM). These resulted in BTTs of 4.6, 6.5 and 7.6 min (EN) and 4.8, 6.5 and 9.1 min (ASTM), respectively. No statistical difference could be observed between the BTT values obtained with the two standard methods for any of the thin gloves. Thus, although the ASTM standard has a lower criterion for the detection of permeation, it does not necessarily produce shorter BTTs. For the better barriers the methods yielded more equivalent permeation rate curves and thus the EN BTTs were longer than the ASTM BTTs: the EN results were 21, 80, 122 and >240 min compared with the ASTM results of 12, 32, 38 and 103 min for glove thicknesses of 0.37 (NR), 0.22 + 0.22 (double layered NR), 0.31 + 0.29 (double layered NR) and 0.19 mm (CR), respectively.

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.

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.

Drawn self-reinforced polyglycolide (SR-PGA) rods, Ø 2 mm and 26 mm long, were implanted in the dorsal subcutaneus tissue of 16 rats. Osteotomies of the distal femur were fixed with SR-PGA rods (2 mm by 15 mm) in another 38 rats. The follow-up times varied from one week to one year. After sacrifice, three-point bending and shear tests were performed for subcutaneously placed rods. Radiological, histological, histomorphometrical, microradiographic, and oxytetracycline-fluorescence studies of osteotomized and intact control femora were also performed. At three weeks the flexural strength of the rods was 50% of the initial value, and the flexural modulus was 46% of the initial value. Five osteotomy specimens had to be excluded due to dislocation or non-union. One of the 33 evaluated osteotomy specimens showed signs of postoperative infection. Thirty-two osteotomies healed uneventfully. No gross signs of inflammatory or foreign-body reaction were observed. The amount of osteoid surface and active osteoid formation surface reached their highest value in the histomorphometrical analysis at 24 weeks. The present investigation demonstrated that the mechanical strength and fixation properties of the drawn SR-PGA rods are suitable for fixation of cancellous bone osteotomies in rats. The present article is the first report on the successful application of drawn SR-PGA rods for fixation of cancellous bone osteotomies.

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.

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.

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., (Copyright 1999 John Wiley & Sons, Inc.)

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.

There are several new and potential uses for absorbable implants. Some will provide exciting options in the future. Ongoing animal and clinical studies will help focus future areas of development.

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.

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.

Totally absorbable internal fixation devices have been used in a total of 2114 operations for the treatment of fractures, arthrodeses and osteotomies at our department between November 1984 and December 1992. The infection rate was 3,5%, for pure polyglycolide (PGA) implants 4% and for pure polylactide (PLLA) implants 0,7%. When the fixation with absorbable implants was compared to that of metallic implants in another series the infection rates were 4% and 9%, respectively. This difference was due to technical reasons. Sinus formation due to a foreign body reaction was observed in 2,5% of 2114 cases and was subsequently infected in 20%.

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.

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.

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.

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.

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.

Absorbable implants made of synthetic biodegradable polymers were recently introduced clinically in internal fixation of fractures. In this prospective study of 71 pediatric patients with a variety of displaced physeal or nonphyseal fractures, self-reinforced polyglycolide pins 1.5 or 2.0 mm in diameter were used instead of Kirschner wires to fix the fragments. The majority of patients (45 children) had a fracture affecting the distal humerus. Mean age of the patients was 9.8 years (range 2-15 years). Follow-up averaged 15.8 months. In 62 patients (87%), an exact reduction of the fracture could be maintained until union. Among the remaining patients, six had minor inaccuracies or redisplacements of the fracture position, but in three patients with supracondylar fractures of the humerus breakage of the pins resulted in a severe redisplacement that necessitated a change in treatment method. With the exception of supracondylar fractures of the humerus, these preliminary results of polyglycolide pin fixation were deemed satisfactory. The fundamental advantage of this method is that no hardware removal procedures are required.

Polyglycolic acid (PGA) has been used worldwide as a biodegradable suture material since 1970. Biodegradable polyglycolide implants were introduced in osteofixation of cancellous bone fractures in 1985. From September 1987 to September 1989, 19 consecutive children with physeal fractures of the distal humerus necessitating open reduction and internal fixation were treated by transphyseal biodegradable fixation using 1.5 x 60-mm2 self-reinforced polyglycolide (SR-PGA) pins. Included were nine displaced fractures of the lateral humeral condyle, five severe avulsions of the medial epicondyle of the humerus, four displaced fractures of the humeral capitellum, and one intraarticular fracture of the medial condyle of the humerus. After accurate reduction, two smooth Kirschner pins 1.5 mm in diameter were introduced across the growth plate for temporary fixation. The metallic pins then were removed one by one and subsequently replaced with the cylindrical SR-PGA pins 1.5 mm in diameter. After operation, a padded plaster splint was worn for four weeks. Neither secondary displacement nor signs of growth disturbance were seen during the 26-month follow-up time (mean, 17.2 months). Not only the reduction of the costs but also the psychological aspects should be considered when dealing with biodegradable fixation of physeal fractures in children. Transphyseal biodegradable fixation has established itself as a procedure of choice for handling simple physeal fractures.

Seven patients with spastic neuromuscular disease and severe hindfoot valgus deformity were treated by subtalar arthrodesis. Arthrodesis was performed in both feet at the same operation and fixed on one side with a self-reinforced poly-L-lactide (SR-PLLA) screw, and with a standard AO screw on the other side. The functional status state was improved, and radiographic union of the arthrodesis occurred in all feet. The radiograph showed better solid fusion in five feet treated with PLLA screws, similar fusion in both sides in one patient, and one slower fusion in the side treated initially with a PLLA screw. Totally absorbable SR-PLLA screws appear to be firm enough for fixation of subtalar extraarticular arthrodesis in children.

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.

The purpose of this study was to examine the effects of an intramedullary self-reinforced polyglycolic acid (SR-PGA), self-reinforced poly-L-lactic acid (SR-PLLA) and a metallic rod on growing bone and their applicability in the fixation of a femoral shaft osteotomy in growing dogs. In 5 dogs, 12 weeks of age, a SR-PGA rod and in another 5 dogs a SR-PLLA rod, both 4.7 mm in diameter and 60 mm in length, were introduced into the intramedullary cavity of the right femur to fix a femoral shaft osteotomy. In a third group of 5 dogs the femoral shaft osteotomy was fixed with an intramedullary metallic rod of equal size. The follow-up intervals were 1, 3, 6, 12, 24 and 48 weeks. Solid union of the osteotomy without secondary displacement was seen radiographically 6 weeks after the operation in all dogs. Neither an intramedullary SR-PGA-, SR-PLLA- nor metallic rod caused any significant disturbance to the longitudinal growth of the operated femur. Narrowing of the femoral neck and a slight valgization of the angle between the femoral neck and shaft without any functional disability was seen 48 weeks after the operation.

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.

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.

220 operations in 211 hands in 160 consecutive patients suffering from Dupuytren's contracture were performed from 1976 through 1984 at the Kuopio University Central Hospital in Finland. 179 operations were carried out as day cases. The mean follow-up was 3.2 years. Sub-total fasciectomy resulted in good immediate and long-term improvement in 86% of patients. The recurrence rate was 27%. Surgical treatment of Dupuytren's contracture was well-suited to day surgery. A properly planned follow-up programme is suggested because of the relatively high rate of recurrence, which usually appeared within two years after operation.

From 1976 through 1985, a total of 1096 children, 0-15 years of age, was treated for fractures in Kuopio University Central Hospital. 131 patients had a femoral shaft fracture and 114 of them, including 82 boys and 32 girls, were studied. The incidence of femoral shaft fracture was 2.16 per 10,000 inhabitants 0-15 years of age. Environmental factors and the ability to move in traffic appeared to be the most important risk factors for femoral shaft fracture.

In a retrospective study we collected patient data relating to clinically detected postoperative thromboembolic complications before (n = 1710) and after (n = 2212) adopting a protocol for prophylaxis of deep vein thrombosis (DVT). A relatively low incidence of clinically diagnosed DVT, four per thousand, before systematic instructions for prophylaxis in 1981 could be explained by the frequent use of dextran as a volume expander in critically ill patients. However, following systematic prophylaxis the frequency of DVT decreased further (one per thousand).

Subtrochanteric osteotomy of the right femur was made in 8 Beagle-dogs 12 weeks of age. After accurate reduction the fixation of the osteotomy was achieved with an intramedullary self-reinforced polyglycolic acid rod. At the follow-up interval of 12 weeks an uncomplicated healing of osteotomy was seen without any growth disturbance. The SR-biodegradable PGA rods provided sufficient stability for rapid healing of subtrochanteric femoral osteotomy in growing dogs.

Physeal fractures occur at a frequency of 15% of all long bone fractures in children. Undisturbed continued bone growth is the main goal of the treatment of these fractures. After the operative reduction and fixation, whenever needed, a second operation for the removal of the pins is inevitable. The purpose of this study was to develop a biodegradable fixation device for transphyseal fracture fixation, abolishing the need of removal operation. Epiphyseal separation of the distal femoral physis was made on the right side in 18 five-week-old rabbits. The fixation of the physeal fracture was made with two self-reinforced polyglycolic acid (SR-PGA) pins 1mm in nominal diameter and 25mm in length. The follow-up times were 3, 6, 12, 24, and 28 weeks. The distal femoral growth-plate of both femurs was analyzed by radiographic, microradiographic, oxytetracycline-fluorescence, histological and histomorphometric studies. Histomorphometric studies showed normal features of growth. Two growth-plate-penetrating transcondylar SR-PGA implants, of 1mm in diameter, provided sufficient stability for the fixation of a distal femoral physeal fracture in a growing rabbit, and did not cause any growth disturbance.

This study examined the fate of a biodegradable polydioxanone (PDS) implant in growing bone in rabbits. In 20 immature rabbits, a PDS rod 2.0 mm in diameter and 25 mm in length was driven into a drill hole of equal bore in the intercondylar portion of the right femur across the central portion of the growth plate. In another 25 immature rabbits, a PDS rod 3.2 mm in diameter and 25 mm in length was driven into a corresponding drill hole using the same technique. The follow-up intervals were three, six, 12, 24, and 36 weeks. The distal femoral growth plates of both femora were analyzed by roentgenographic, microroentgenographic, oxytetracycline-fluorescence, histologic, and histomorphometric studies. Histomorphometric studies showed clear changes at the site of injury and appeared to be an excellent means of providing an exact numerical description of the different cellular areas of the growth plate in experimental studies. A transphyseal PDS implant 2.0 mm in diameter did not cause any permanent growth disturbance of the femur in a growing rabbit. An implant 3.2 mm in diameter caused a growth disturbance similar to a drill hole of equal bore.

A polyglactin 910 rod 3.2 mm in diameter and 25 mm in length was driven in a drill hole in the intercondylar portion of the right femur across the central portion of the growth plate in 20 5-week-old rabbits. The follow-up times were 3, 6, 12, and 24 weeks. The distal femoral growth plates of both femurs were analyzed by radiographic, microradiographic, and oxytetracycline fluorescence, histological, and histomorphometric studies. Histomorphometric studies showed clear changes at injury site and appeared to be an excellent means of exact numerical description of the different cellular areas of the growth plate. Six weeks after implantation, a polyglactin 910 implant resulted in a growth disturbance similar to that of a drill hole of equal bore.

Forty-four rabbits were operated on when five weeks old; in one group a 2 mm drill-hole was made in the intercondylar portion of the right femur across the central portion of the growth plate up to the diaphysis, while in the other group a similar drill-hole of 3.2 mm was made. At 3, 6, 12 and 24 weeks after operation, specimens from the growth plates of both femora were analysed using radiographic, microradiographic, histological and histomorphometric techniques. It was found that destruction of 7% of the cross-sectional area of the growth plate caused permanent growth disturbance and shortening of the femur.