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At least 127 records · Page 7Linked to original sources
PubMed2006

[Distal intraarticular humerus fractures in elderly patients. Treatment with combined percutaneous screw fixation and an external fixator].

BACKGROUND: Intra-articular distal humerus fractures are relatively uncommon. Due to osteoporosis in elderly patients, stable fixation still remains a problem despite new implants providing angular stability. MATERIAL AND METHODS: The treatment of choice is open reduction and plate fixation requiring an extended approach with olecranon osteotomy often combined with additional postoperative immobilisation in a long arm cast. We describe a technique using closed reduction and percutaneous osteosynthesis with cannulated screws combined with external fixation. Morbidity due to surgical exposure and potential risks are diminished while functional results are comparable to open reduction and internal fixation . In contrast to plasters or casts, the use of an external fixator allows stable and safety protection of the elbow joint, preserving wrist function as well as forearm rotation and increasing the patient's comfort during immobilisation. RESULTS: We have used this technique on ten patients aged 76.2 years (range 67-88 years). According to the AO classification, there were three B-1/B-2 fractures, four C-1 and three C-2/C-3 fractures without severe comminution. The duration of external fixation was 6.3 weeks (range 4-8 weeks) before fracture union was achieved. This allows the initiation of physiotherapy and motion of the elbow. There was only one revision caused by the necessary replacement of an aseptic loosened Schanz screw. At follow-up 3 months postoperatively, the range of motion of the elbow was 95 degrees (65 degrees-105 degrees ), average extension 25 degrees (10 degrees-35 degrees ) and mean flexion was 115 degrees (100 degrees-120 degrees ) with all patients exhibiting full pro/supination.

Aged↗
PubMed2005

Assessment of fixatives, fixation, and tissue processing on morphology and RNA integrity.

Molecular characterization of morphologic change requires exquisite tissue morphology and RNA preservation; however, traditional fixatives usually result in fragmented RNA. To optimize molecular analyses on fixed tissues, we assessed morphologic and RNA integrity in rat liver when sections were fixed in 70% neutral-buffered formalin, modified Davidson's II, 70% ethanol, UMFIX, modified Carnoy's, modified methacarn, Bouin's, phosphate-buffered saline, or 30% sucrose. Each sample was subjected to standard or microwave fixation and standard or microwave processing, and sections were evaluated microscopically. RNA was extracted and assessed for preservation of quality and quantity. Modified methacarn, 70% ethanol, and modified Carnoy's solution each resulted in tissue morphology representing a reasonable alternative to formalin. Modified methacarn and UMFIX best preserved RNA quality. Neither microwave fixation nor processing affected RNA integrity relative to standard methods, although morphology was modestly improved. We conclude that modified methacarn, 70% ethanol, and modified Carnoy's solution provided acceptable preservation of tissue morphology and RNA quality using both standard and microwave fixation and processing methods. Of these three fixatives, modified methacarn provided the best results and can be considered a fixative of choice where tissue morphology and RNA integrity are being assessed in the same specimens.

Animals↗
PubMed2001

Observations concerning different patterns of bone healing using the Point Contact Fixator (PC-Fix) as a new technique for fracture fixation.

The recent trend in all surgical disciplines has been the development of techniques in minimally invasive surgery and the optimal maintenance of the blood supply to the bone fragments during osteosynthesis. Currently, the Point Contact Fixator (PC-Fix) has been introduced as a new implant for the stabilization of forearm bones. This plate-like splint and screw fixation system, which actually acts as an internal fixator, is characterized by minimized isolated contacts to the bone and proven angular stability of the monocortically locked screws. By using the PC-Fix, a further reduction of damage to the blood supply to the bone is achieved. Since 1994, 38 patients have been treated with this new device; we have reviewed the radiographs of 52 consolidated forearm fractures/osteotomies in accordance with the patterns of bone healing associated with the different methods of implant application according to the fracture type. In the groups in which traditionally precise reduction, interfragmentary compression and stable fixation was achieved (N=31), we found in 71% an absence of periosteal callus (direct bone healing). In the groups in which compression and adaptation were combined, or even main fragments adapted without compression, with wedges remaining unreduced in soft tissue connection (N=21), we found a visible external callus in 81% (indirect healing) (P = 0.002). Indirect healing after internal fixation is no longer regarded as a disturbance to healing, but is a goal in itself. The appearance of callus is a welcome sign indicating a prompt and positive reaction in the course of bone union which will lead to progressive fracture immobilization. When using the PC-Fix in a "biological way", callus formation and solid union take place earlier than in conventional plating. The new internal fixator offers substantial technical and mechanical advantages in fracture treatment. Therefore, it is an ideal implant to satisfy the requirements of modern biological osteosynthesis without compromising the restoration of axial alignment, rotation, length and postoperative functional treatment.

Adolescent↗
PubMed2003

[Our experiences with change of osteosynthesis from external fixator to internal fixation in fractures of the lower limb].

INTRODUCTION: In polytrauma patients and fractures with severe soft tissue damage of the lower limb the use of external fixator is indicated. To show the possibilities and limits of change of external fixation to internal osteosynthesis we performed a retrospective analysis. PATIENTS AND METHODS: Between 1.1.1993 to 30.6.1997 671 cases were primarily treated with external fixator. After a mean of 16.5 days a change of osteosynthesis was performed in 75 cases. RESULTS: 5 infections of the pin tracks, 3 infections of the wound, two thromboses, one case of thromboembolism and one osteomyelitis were seen in these 75 cases. One patient died due to severe brain damage after head injury. No further operations were necessary, all fractures showed primary healing. Taking the severe soft tissue damages and severe multiple trauma into account only few complications were observed. CONCLUSION: The main problems and risks of internal fixation occur in the early phase of treatment, whereas complications after external fixation are more likely to occur in later stages. By a change from external fixation to internal osteosynthesis the advantages of both methods can be combined.

Accidents, Traffic↗
PubMed2002

[Biomechanical comparative study of lumbosacral fixation and Jackson intrasacral fixation].

OBJECTIVE: To assess the biomechanical properties of Jackson intrasacral fixation technique and other lumbersacral internal fixation systems, and to provide the basis of biomechanics for the clinical application of Jackson technique. METHODS: The biomechanical properties of Dick, RF, Steffee, CD, and Jackson technique were studied by testing the inflexion, extension, compression, torsion, and lateral bending in 15 calf fresh-frozen specimens and 5 fresh-frozen human cadavaric specimens, which were divided into 5 groups with similar bone density. RESULTS: Jackson intrasacral fixation device was stiffer than any other devices. On the "load-displacement" curve, Jackson intrasacral fixation device was predominant compared with other devices (P < 0.01). CONCLUSION: Jackson intrasacral fixation system is an effective device for lumbosacral fixation.

Animals↗
PubMed2005

[Treatments of tibial Pilon fractures with a combination of limited internal fixation and external fixation].

OBJECTIVE: To summarize the effect and complication of treatment for Pilon fracture using limited internal fixation combined with external fixation. METHODS: From April 1996 to June 2003, 20 patients with Pilon fracture were treated with limited internal fixation combined with external fixation as the treatment group and 22 patients with Pilon fracture with other methods as the control group. The X-ray films, clinical effect and complication were analyzed and compared between 2 groups. RESULTS: All cases were followed up for 8 to 26 months (15.2 months on average). According to Helfet's criterion for clinical effect, the excellent and good rates were 75% in the treatment group and 72.7% in the control group, being no significant difference (P > 0.05). According to Burwell-charnley criterion for reduction, the X-ray film results showed the excellent and good rates were 90% in the treatment group and 86.4% in the control group, being no significant difference (P > 0.05). But there was significant difference in complications between 2 groups (P < 0.05). CONCLUSION: Limited internal fixation combined with external fixation is better in resuming ankle joint function and remarkably reducing complication, especially in reducing soft tissue complication and collapse of bone joint; it is useful in the treatment of Pilon fracture.

Adult↗
PubMed2006

[What advantages does volar plate fixation have over K-wire fixation for distal radius extension fractures in the elderly?].

PURPOSE: The purpose of this retrospective study was to compare the outcome of open reduction and internal fixation (ORIF) followed immediately by physiotherapy and of percutaneous K-wire-fixation and casting for unstable distal radius fractures in elderly patients, considering the results both in general, for all such fractures, and selectively for A3 and C2 fractures. METHODS: Follow-up examinations were performed 26 (18-48) months after surgery in 43 patients (median age 67 (60-83) years) treated with K-wire fixation and 9 (5-17) months after surgery in 46 patients (median age 76 (60-90) years) treated with ORIF, and the outcome of each was recorded as Disabilities of the Arm, Shoulder and Hand (DASH), Gartland-Werley and Castaing scores; the radiological loss of correction was also assessed. Statistical analysis was performed first without reference to the specific type of fracture for the K-wire- and the total ORIF -groups, and then selectively for A3 and C2 -fractures only; in the second analysis the patients were divided into three groups: KD, ORIF with and ORIF without angular stability. RESULTS: The Garland-Werley and Castaing scores do not indicate any significant difference between the procedures specified. According to the Garland-Werley score 37 patients (86%) treated by K-wire fixation and 39 (85%) treated by ORIF achieved "excellent" and "good" results; according to the Castaing score there were 33 (77%) "good" results after K-wire fixation and 34 (74%) good results after ORIF. The radiological loss of correction (K-wire fixation/ORIF) as measured by the radial inclination (median 2/2.5 degrees), the palmar tilt (median 3/5 degrees) and the radial shortening (median 1/1 degrees mm) do not differ significantly. Suboptimal radiological results do not always correlate with results that are only "fair" or "poor". The non-fracture-specific DASH score suggests a higher degree of patient satisfaction after K-wire fixation (7 [0-87] points) than after ORIF (17 [0-82] points), which is not confirmed by fracture-specific evaluation. There is a significantly earlier return to the "activities of daily living" (4 as against 8 weeks) after ORIF. CONCLUSION: All the treatments compared are suitable for the treatment of A3 and C2 fractures. The important advantages of ORIF are the early functional physiotherapy without casting and without obligatory second surgery and the earlier return to "activities of daily living", which are all of decisive importance for older patients, who are the ones most frequently affected.

Aged↗
PubMed2004

Fixation strength of a novel bioabsorbable expansion bolt for patellar tendon bone graft fixation: an experimental study in calf tibial bone.

This biomechanical study compares the initial fixation strength of a novel bioabsorbable two-shell expansion bolt (EB) with that of a well-established interference-screw technique in bone-patellar tendon-bone (BPTB) reconstruction in a calf model. Thirty tibia plateaus (age 5-6 months) were assigned to three groups: In groups I and II, trapezoidal bone plugs of BPTB grafts were fixed with bioabsorbable poly-L-lactide interference screws (8 x 23 mm) or titanium interference screws (8 x 25 mm) respectively. In group III, semicircular grafts were fixed using bioabsorbable poly-D, L-lactide expansion bolts (5.8/8.7 x 10 x 35 mm). The tensile axis was parallel to the bone tunnel, and the construction was loaded until failure applying a displacement rate of 1 mm per second. In group II the mean ultimate loads to failure (713 N+/-218 N) were found to be significantly higher than those of groups I (487 N+/-205 N) and III (510 N+/-133 N). Measurement of stiffness showed 45 N/mm+/-13.3 in group I, 58 N/mm+/-17.4 in group II and 46 N/mm+/-6.9 in group III, and did not demonstrate significant differences. We found a correlation between insertion torque and wedge insertion force and ultimate loads to failure in all groups (r=0.53 in group I, r =0.54 in group II, and r =0.57 in group III). Cross-section planes of bone tunnel increased by 51%, 30% and 31% respectively, following insertion of screws or expansion of bolts (p<0.05). We conclude that ACL graft fixation by means of the presented expansion bolt demonstrates a fixation strength similar to the established bioabsorbable screw fixation, and is a reasonable alternative fixation method, especially since some of the specific pitfalls of screw fixation can be avoided.

Absorbable Implants↗
PubMed1995

Stability of Le Fort I osteotomy with maxillary advancement: a comparison of combined wire fixation and rigid fixation.

PURPOSE: This study compares two types of fixation: intraosseous wires, skeletal suspension wiring, and maxillomandibular fixation (combined wire fixation; CWF) with rigid internal fixation (RIF) in patients who underwent Le Fort I osteotomy to correct maxillary hypoplasia. MATERIALS AND METHODS: All patients were operated on by the same surgeon using a standard technique, which included bone grafting. The 12 patients in group A were treated with CWF for 4 weeks. Group B was made up of 13 patients who had RIF and training elastics for 4 weeks. Cephalometric analysis using a commercial software package was performed on radiographs that were taken immediately preoperatively (T1), 1 day postoperatively (T2), and at least 1 year postoperatively (T4). The position of the maxilla in relation to the cranial base and Frankfort plane at each time interval was compared. RESULTS: Postsurgical horizontal change (maxillary position change from T2 to T4) for both groups was in the posterior direction. In group A, six patients had less than 1 mm change, three had 1 to 2 mm change, and three had > 2 mm change. In group B, 10 patients had less than 1 mm change, three had 1 to 2 mm change and 0 had > 2 mm change. Comparison of mean values of groups A and B suggested improved stability with rigid versus wire fixation in the horizontal plane; however, statistical analysis of adjusted mean values showed no significant difference. Vertical changes in maxillary position were also measured from postoperatively to 1 year (T2 to T4). The vertical changes were minimal in those cases of maxillary advancement where no vertical changes were planned; however, there was a statistically significant (P = .0024) improved stability with RIF versus combined wire fixation cases. Comparison of adjusted means showed double the amount of vertical setting 1 year postoperatively in the CWF group. CONCLUSION: Overall, 22 of 25 patients with horizontal maxillary advancement had excellent stability at 1 year. Observed trends suggest that RIF may have improved stability over CWF.

Adult↗
PubMedDate not supplied

[Stiffness of the AO spinal external fixator. Experimental results of stiffness of the AO spinal external fixator with 3 different pedicle screw systems].

The stiffness of the AO external pedicular fixator was analysed in an experimental laboratory study using three different sets of pedicle screws and different configurations of the implant. The experiments were performed with a wooden model as well as with bi-segmental human lumbar spine specimens with disc and ligaments intact. The capacity of the AO external pedicular fixator to compensate axial load, transversal- and torsion forces was compared to physiological requirements. Of particular interest was the effect of preload on the axial stiffness. It is demonstrated that the axial stiffness of the AO external pedicular fixator is so low that the axial load on the lumbar spine level in humans cannot be influenced by the fixator even when preloaded. However the resistance against torsion and transversal slipping is probably higher than required in vivo. No significant differences were found between the three types of pedicular screws. The effect of the triangular counter nuts of the AO external pedicular fixator on the transversal- and torsion stability was important. The presented results suggest that the AO external pedicular fixator can be of significant value in segmental rotation- and translocation pathologies of the lumbar spine and that the effect of isolated segmental distraction has probably been overestimated.

Bone Screws↗
PubMed1991

Unilateral external fixation until healing with the dynamic axial fixator for severe open tibial fractures.

One hundred one cases of open tibia fractures were treated until healing with a unilateral external fixation device that permits fracture site compression with weight bearing. There were 38 type II and 63 type III (24 IIIA, 33 IIIB, six IIIC) open fractures. A standard protocol was followed including irrigation and debridement and, when necessary, flap coverage (19 cases) and bone grafting (31 cases). Fixators were applied at the first debridement and removed when the fracture was healed. All patients were permitted early partial weight bearing and progressed to full weight bearing with fixator dynamization. Ninety-six cases healed in the fixator (12-50 weeks; average, 24.6). Three of the five failures were associated with screw complications. Five patients required screw changes and 29 required oral antibiotic therapy for screw complications. Ninety-five percent of healed cases had angulation of less than 10 degrees (in any plane). There were only six fracture site infections during the course of treatment. Dynamic axial fixation may be applied at the first debridement and be used until healing in severe open tibia fractures. Change of the fixator to another treatment method is not required.

Adolescent↗
PubMed2005

Posterior fixation of thoracolumbar burst fracture: short-segment pedicle fixation versus long-segment instrumentation.

OBJECTIVE: The treatment of thoracolumbar burst fracture is a controversial issue. Short-segment (SS) pedicle fixation has become a popular treatment option. However, there are several studies regarding the high rate of failure. The aim of this prospective study was to compare SS versus long-segment (LS) instrumentation. METHODS: For this purpose, 18 consecutive patients were assigned to two groups. Group 1 included nine patients treated by SS pedicle fixation, whereas group 2 included nine patients treated by LS instrumentation. SS instrumentation was pedicle fixation one level above and below the fractured vertebra. LS instrumentation was hook fixation (claw hooks attached to second upper vertebra and infralaminar hooks attached to first upper vertebra) above and pedicle fixation (pedicle screws attached to first and second lower vertebrae) below the fractured vertebra. RESULTS: As a result, measurements of local kyphosis, sagittal index, and anterior vertebral height compression showed that the LS group had a better outcome at final follow-up (P < 0.05). Also, the SS group had a 55% failure rate, whereas the LS group had prolonged operative time and increased blood loss. However, there was no difference between the two groups according to Low Back Outcome Score. CONCLUSIONS: In conclusion, radiographic parameters demonstrated that LS instrumentation is a more effective management of thoracolumbar burst fractures. Nevertheless, clinical outcome was the same between the two groups. However, our conclusions were based on posterior-only surgery. Anterior column support would negate the need for LS fixation. Also, SS would have been more successful if two above and two below pedicle screws were used.

Adolescent↗
PubMed2003

Tibial lengthening: technique for speedy lengthening by external fixation and secondary internal fixation.

BACKGROUND: The conventional Ilizarov technique for tibial lengthening is frequently time-consuming, causes suffering, and is associated with many complications. This study takes a retrospective approach to investigate the outcome of applying a slightly speedier procedure using an Ilizarov apparatus and secondary internal fixation. METHODS: Twelve adult patients displaying tibial shortening (median, 4.0 cm; mean, 4.6 cm; range, 3.0-12.0 cm) with various causes were treated with or without tibial osteotomy and stabilized using an Ilizarov lengthening apparatus. Postoperatively, lengthening of 1 to 1.5 mm/day was performed until the desired length was achieved. External fixation was then converted to internal fixation and either pure autogenous bone graft, or a mixture of autogenous and allogenous bone graft was supplemented. Postoperatively, protected weight bearing was advised until bony union was achieved. RESULTS: Eleven patients were followed up for a median of 3.4 years (mean, 4.0 years; range, 2.1-6.7 years) and solid union was achieved in all cases. Median external fixation occurred after 1.8 months (mean, 1.9 months; range, 1.2-4.5 months) and the median time until union after internal fixation was 4.5 months (mean, 4.8 months; range, 4-6 months). Two patients with rigid equinus feet required concomitant Achillis tendon lengthening. No other significant complications were noted. Classification of the results revealed that improvement from an unsatisfactory to a satisfactory outcome was achieved in all patients (p < 0.001). CONCLUSION: The described technique shortens the external fixation period and reduces patient suffering. Moreover, a high union rate and a low complication rate are achieved. Subjectively and objectively, patients can achieve satisfactory outcomes. Consequently, the described technique may be considered as an alternative to conventional techniques when indicated.

Adult↗
PubMed1981

Swelling of mitochondria in immersion-fixed liver tissue. Effect of various fixatives and of delayed fixation.

In order to study the occurrence of swollen and disrupted mitochondria in tissue preserved for electron microscopy by ordinary fixation methods, liver tissue from miniature pig fetuses was immersion-fixed in fixatives with various types and concentrations of fixing agents and vehicles. Also commercial and purified products have been tested, different fixation times and temperatures as well as the consequences of a short rinsing in buffer solutions prior to fixation. Furthermore, the significance of delayed fixation (autolysis) was studied. It was found that swollen and disrupted mitochondria occur predominantly in liver cells exposed to low concentrations of glutaraldehyde. It is shown that this phenomenon is a result of a specific effect of glutaraldehyde on the mitochondrial membranes. It is not accompanied by parallel changes of other organelles or nuclei, and it not provoked by other fixing agents, vehicles or by delayed fixation (autolysis).

Animals↗
PubMedDate not supplied

The fixation strength of six hamstring tendon graft fixation devices in anterior cruciate ligament reconstruction. Part II: tibial site.

BACKGROUND: Tibial fixation is more problematic than femoral fixation in anterior cruciate ligament reconstruction. HYPOTHESIS: There is no difference in initial fixation strength among hamstring tendon graft tibial fixation devices. STUDY DESIGN: Randomized experimental study. METHODS: Each of six devices used to fix 120 quadrupled human semitendinosus-gracilis tendon grafts into porcine tibiae was tested 10 times with a single-cycle load-to-failure test and 10 times with a 1500-cycle loading test. Specimens surviving cyclic loading were subjected to a single-cycle load-to-failure test. RESULTS: Intrafix (1332 N) was the strongest in the single-cycle load-to-failure test, followed by WasherLoc (975 N), tandem spiked washer (769 N), SmartScrew ACL (665 N), BioScrew (612 N), and SoftSilk (471 N). After cyclic-loading tests, Intrafix showed the lowest residual displacement (1.5 mm) and was also strongest (1309 N) in the single-cycle load-to-failure test after the cyclic-loading test, followed by WasherLoc (3.2 mm; 917 N). CONCLUSION: The Intrafix provided clearly superior strength in the fixation of hamstring tendon grafts to the tibial drill hole. CLINICAL RELEVANCE: Some caution may be warranted when using the implants that showed increased residual displacement, especially if aggressive rehabilitation is to be used. Preconditioning of the hamstring tendon graft-implant complex before tibial fixation is needed.

Analysis of Variance↗
PubMedDate not supplied

Comparison of initial fixation strength between biodegradable and metallic interference screws and a press-fit fixation technique in a porcine model.

The objective of this study was to evaluate the initial fixation strength of a biodegradable interference screw compared with press-fit fixation and a titanium interference screw in anterior cruciate ligament reconstruction using a bone-patellar tendon-bone graft. Porcine lower limbs were used. The specimens underwent 500 loading cycles between 60 and 250 N. This corresponds to loads in the graft during aggressive rehabilitation. Thereafter, intact specimens were loaded to failure. Failure mode was defined by visual analysis. Under cyclic loads none of the interference screw fixations failed. In the press-fit group (angle between load axis and tunnel axis 80 degrees), five specimens failed. The mean maximal load to failure was 945 N (+/- 87) for the titanium screw, 797 N (+/- 60) for the biodegradable screw, and 708 N (+/- 211) for the five press-fit specimens that did not fail during cyclic loading. With respect to primary fixation strength, biodegradable screws are a reasonable alternative to titanium interference screws. The press-fit fixation did not provide a secure fixation in all cases. Five press-fit specimens failed under cyclic loads comparable with those seen under conditions of accelerated rehabilitation.

Absorbable Implants↗
PubMed1986

A histological comparison of phase-partition fixation with fixation in aqueous solutions.

In phase-partition fixation, tissue is immersed in a non-aqueous solvent at equilibrium with an aqueous solution of a fixing agent to minimize osmotic effects. Preservation of morphology afforded by phase-partition fixation using formalin and glutaraldehyde and several organic solvents was compared to aqueous 10% neutral buffered formalin fixation for five tissues. It was shown that phase-partition fixation can provide excellent fixation for light microscopy if the proper combinations of fixatives and solvents are used.

Animals↗
PubMed1995

Cannulated screws for odontoid screw fixation and atlantoaxial transarticular screw fixation. Technical note.

Cannulated screw systems use thin Kirschner wires (K-wires) that have been drilled into the bone to direct screw trajectories accurately into small bone fragments. Use of the K-wires avoids overdrilling the pilot holes and allows fixation of adjacent bone fragments during screw insertion. Hollow tools and hollow screws are inserted into the bone over the K-wires. Cannulated screw fixation is useful in the cervical spine to stabilize odontoid fractures and to treat atlantoaxial instability. This report describes techniques for successful cannulated screw insertion and methods to minimize complications. Cannulated screws have several distinct advantages compared to noncannulated screws: 1) the K-wires guide the screw position into the bone; 2) the K-wire trajectory can be repositioned easily if the original trajectory was not ideal; 3) the K-wires allow continuous fixation of adjacent unstable bone fragments; and 4) the K-wires prevent migration of unstable bone fragments during screw insertion. Complications associated with the K-wire (breakage, repositioning, and advancement) can be minimized using precise operative techniques, a specialized tool system, and intraoperative fluoroscopic monitoring. A unique cannulated screw tool system was developed specifically for upper cervical fixation to allow percutaneous drilling using long tunneling devices, tissue sheaths, drill guides, and long K-wires. These tools allow delivery of cannulated fracture-fixation screws at a low angle to the spine through long soft-tissue trajectories. Cannulated screws have significant advantages compared to noncannulated screws for fixation of the unstable cervical spine.

Bone Screws↗