Biomedical subjects

E K Partio

Publications and source records attributed to E K Partio.

29 records · Page 2Linked to original sources

PubMed1996

Strength of the fixation of patellar tendon bone grafts using a totally absorbable self-reinforced poly-L-lactide expansion plug and screw. An experimental study in a bovine cadaver.

In a bovine cadaver study, bone-tendon-bone graft fixation strength with different graft geometry and fixation devices was measured to evaluate the fixation strength of totally absorbable implants: a 6.0-mm expansion plug and 6.3-mm screw both made of self-reinforced polylactide (SR-PLLA). Comparison was made with 6.5-mm AO cancellous screw. Maximum tensile force to dislodge the bone plug from the bone tunnel was recorded. First, two preliminary tests were performed. In the first test, triangular bone plugs were used (9-mm diameter). The direction of the pull force was parallel to the bone tunnel. The maximum tensile forces were 786 N in femoral insertions and 625 N in tibial insertions, mean. After this, we evaluated the influence of change in the pullout direction. In the second test, a circular bone plug was used with no fixation but the direction of the pull force was parallel to the tibial or femoral axis and the bone plug (10-mm diameter) was in a 30 degrees to 40 degrees angle to the direction of the pull force and it was compressed to the tunnel (9-mm diameter). The maximum tensile forces were 783 N in femoral insertions and 695 N in tibial insertions, mean. In the final third test, we used a curved saw in harvesting the graft. This made a half-circular bone block with a diameter of 12 mm. The maximum tensile force to dislodge the bone plug from the bone tunnel was recorded and the pull force was in a 30 degrees to 40 degrees angle to the tunnel. The results were evaluated with Student's t-test and Mann-Whitney U-test. With the AO screw, the maximum tensile force to dislodge the bone plug from the bone tunnel was 2,113 +/- 407 N (mean +/- standard deviation) and it was better than the fixation strength of the SR-PLLA expansion plug, 1,379 +/- 328 N (P = .009, t-test) and better than the fixation strength of SR-PLLA screw, 1,454 +/- 230 N (P = .007, t-test). However, the maximum tensile force of both SR-PLLA implants in all measurements in the third test were above 1,100 N and it seems that the initial strength of totally absorbable implants is enough for the clinical use.

Animals↗

PubMed1996

Absorbable devices in the fixation of fractures.

Totally absorbable internal fracture fixation devices were introduced clinically in the treatment of fractures and osteotomies of the extremities at our department in 1984. A total of 2,500 patients were managed using bone or ligament fixation devices made of self-reinforced (matrix and fibers of same polymer) absorbable alpha-hydroxy polyesters between November 5, 1984, and January 12, 1994. The devices used included cylindrical rods or pins, screws, tacks, plugs, and wires. The most common indication for the use of absorbable implants was displaced malleolar fracture of the ankle. Transphyseal fixation with small-diameter polyglycolide pins was used in children. The postoperative clinical course was uneventful in over 90% of the patients. The complications included bacterial wound infection in 3.6% and failure of fixation in 3.7%. In one-fifth of these cases, however, reoperation was not necessary. The occurrence of noninfectious foreign-body reactions 2 to 3 months postoperatively has been observed in 2.3% of the patients operated in the last years with polyglcolide implants but in none of the patients with polylactide implants. This inflammatory tissue response often required aspiration with a needle or small incision but did not influence the ultimate functional or radiologic result of treatment. Owing to the biodegradability of these internal fixation devices, over 1,000 implant removal procedures were avoided during the 9-year period under review, allowing medical personnel at these facilities to focus on other procedures. Avoidance of removal procedures results in financial benefits and psychological advantages. The benefits of absorbable implants for war surgery are the same as for civilian life. Absorbable implants can also be used in open fractures and infection operations.

Absorption↗

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↗

PubMed1996

A prospective controlled trial of the fracture of the humeral medial epicondyle--how to treat?

Twenty-one patients, 11 male and nine female, with fracture of medial humeral epicondyle were treated. The mean age of the patients was 21 (range 8-52) years. The average initial displacement was 13 (range 3-24) mm, and four out of 21 patients had a dislocation of the elbow joint. Two patients were first treated conservatively, but later on operation for removal of the non-united fragment and reattachment of the ligaments and muscles was necessary. One patient was treated by primary excision of the fragment. Eighteen patients were treated by open reduction and internal fixation using self-reinforced polyglyclycolide (SR-PGA) screws in five patients, poly-l-lactide (SR-PLLA) screw in one, small (SR-PGA) rods in seven and Kirschner-wires in five patients. Solid union took place in 14 out of 18 patients and a good stability of the elbow joint was achieved. Fifteen patients scored an excellent result according to the scale of Broberg and Morrey. Although this series was not randomly allocated in respect of the method of treatment, it shows that medial epicondylar fractures can be fixed with absorbable implants without any need for removal procedure.

Adolescent↗

PubMed1996

Biodegradable self-reinforced polyglycolide screws and rods in the fixation of displaced malleolar fractures in the elderly. A comparison with metallic implants.

Biodegradable self-reinforced polyglycolide screws and rods were constructed for internal fixation of fractures in cancellous bone. The self-reinforced texture was achieved by embedding polyglycolide fibres in a polyglycolide matrix. In a prospective clinical study, a total of 37 patients at least 65 years of age with displaced malleolar fractures were managed by open reduction and internal fixation using either biodegradable screws and rods or metallic implants in a randomly allocated series. The results were assessed approximately one year after the fracture. One wound infection occurred after metallic fixation. Reoperation because of displacement of the fracture was needed in one patient after biodegradable fixation. The functional results were satisfactory in most patients. There were no major difference in the end results between both operative methods used.

Activities of Daily Living↗

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↗

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

[Immobilization and early mobilization of malleolar fractures after osteosynthesis with resorbable bone screws].

71 patients with displaced ankle fracture were treated by using absorbable screws in the fixation of fractures. The follow-up time was 17 (13 to 33) months in average. The fixation devices were SR-PLLA (self-reinforced poly-L-lactide) and SR-PGA (self-reinforced polyglycolide) screws. 38 of the ankle fractures were immobilized with plaster cast and 33 ankle joints were mobilized immediately with a brace. An exact radiological result was achieved in 66 cases, insignificant displacement was observed in four cases and the result was poor in one patient. The result was classified as excellent in 62 patients, as good in eight patients and as poor in one patient. The patients treated postoperatively without plaster healed in a somewhat shorter time, but at one year check-up the differences in the clinical results were almost eliminated. Selected ankle fractures fixed with absorbable screws can be treated postoperatively with early mobilization without plaster.

Adolescent↗

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

Talocrural arthrodesis with absorbable screws, 12 cases followed for 1 year.

In 11 patients, 12 arthrodeses of the ankle joint were performed by using absorbable self-reinforced poly-l-lactide (SR-PLLA) or polyglycolide (SR-PGA) screws. 8 patients had posttraumatic arthrosis, 3 rheumatoid arthritis, and 1 rigid flexion contracture of the ankle due to neuropathy. The average follow-up time was 14 (7-22) months. Solid fusion was achieved in 11 of 12 cases in 9(6-16) weeks.

Absorption↗

PubMedDate not supplied

Totally absorbable screws in fixation of subtalar extra articular arthrodesis in children with spastic neuromuscular disease: preliminary report of a randomized prospective study of fourteen arthrodeses fixed with absorbable or metallic screws.

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.

Adolescent↗