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At least 145 records · Page 8Linked to original sources
PubMed2004

Ilizarov external fixation salvage of failed intramedullary fixation of tibia with nail retention.

Failure of intramedullary fixation of the tibia presents a unique problem, as improving fracture alignment is often difficult after nail placement. The purpose of this study was to demonstrate the effectiveness of the Ilizarov technique in obtaining anatomic union after failed intramedullary fixation of the tibia. We reviewed medical records and plain radiographs of 4 men who, at a tertiary-care facility, presented with failed intramedullary fixation of the tibia. Mean age was 28 years (range, 23-36 years). All 4 patients underwent reduction and external fixation by the llizarov technique with retention of the intramedullary nail. Anatomic union was attained in each case. Thin-wire circular-frame external fixation by the Ilizarov technique was a viable salvage option for failed intramedullary fixation of the tibia.

Adult↗
PubMed2004

External fixation versus internal fixation for closed unstable intra-articular fracture of the distal radius. Early results from a prospective study.

This is a prospective study of a series of 26 patients with closed unstable comminuted intra-articular fracture distal end of the radius treated with two different methods of treatment to compare their anatomical and functional results. The external fixation group consisted of 12 patients and internal fixation group consisted of 14 patients. The anatomical and functional assessments were performed at six months and one year. The anatomical results at six months and one year showed that the internal fixation group was effective in maintaining the reduction compared to the external fixation group. The radial height, volar tilt and radial inclination were well maintained. However, the functional results at six months and one year showedno differences between these two types of fixation. The complication rate was higher in external fixation group.

Adolescent↗
PubMed1991

Microwave fixation provides rapid, primary fixation for light and electron microscopy and for immunohistochemistry and immunocytochemistry.

A relatively new approach to specimen preservation for morphologic studies uses microwave energy and chemicals. Microwave fixation can produce fixation results equal in quality to chemical fixation methods and equal in speed to freeze fixation methods. The importance of this microwave fixation technology lies in its potential to provide a standardized fixation approach in histopathology, immunohistochemistry, and immunocytochemistry.

Animals↗
PubMed1993

Two-stage operative treatment of comminuted os calcis fractures. Primary indirect reduction with medial external fixation and delayed lateral plate fixation.

The indication for otherwise established lateral plate fixation in fractures of the calcaneus becomes relative when severe comminution (Sander's Type III and IV) of the bone involves concomitant massive soft-tissue swelling. The calcaneus is shortened, Böhler's angle flattened, and lateral bulging and varus deformity persist throughout the six or more days needed for soft-tissue compromise to recede. Intraoperatively, problems with anatomic reduction are encountered primarily because of soft-tissue shrinkage and muscle contraction, underscoring the rationale for conservative treatment modalities. A two-stage approach--primary medial external fixation and delayed lateral plate fixation--stabilizes the calcaneus in a nearly anatomic position by calculated distraction through medial external fixation, leaving joint congruency to be restored in a secondary procedure, when soft tissues pose no problem for a lateral approach. The two-stage procedure was used in 13 of 49 cases, in which soft-tissue compromise was severe. Anatomic primary reduction greatly facilitated delayed lateral plate fixation. Infection rates were not traced to the external fixation. Massive bone grafting was associated with a high occurrence of complications.

Ankle Injuries↗
PubMed1995

[Combination of the Ilizarov ring fixator with the unilateral AO tube fixator. Initial clinical experiences with the hybrid system].

Ring fixation of the tibia is difficult because of soft tissue transfixation and the size and weight of the external fixator. To increase the patients comfort K-wire and half-pin fixation are combined in a new hybrid configuration. The Ilizarov ring fixator with K-wire or Schanz screw fixation is combined with the unilateral AO fixator. This configuration has so far been used in 17 cases: in the proximal and intraarticular tibia in 7 cases, in the distal tibia in 8 cases and in the femur in 2 cases. As experience with the hybrid system widens indications accepted are metaphyseal and intraarticular fractures of the tibia with severe soft tissue damage, open fractures, segmental defects and fractures of the tibia that cannot be nailed. Loosening of the hybrid construction requiring an additional operative procedure has not occurred. The hybrid system is minimally invasive and allows early weight-bearing. It has the advantages of less transfixation of the soft tissue, an easy operative technique and more comfort with higher patient compliance, and the options for corrective procedures are the same as with the conventional Ilizarov technique. Our preliminary first experience with this system is encouraging; it is especially useful for problematic epi- and metaphyseal fractures with severe soft tissue damage.

Adult↗
PubMed2001

High energy plafond fractures treated by a spanning external fixator initially and followed by a second stage open reduction internal fixation of the articular surface--preliminary report.

UNLABELLED: Early open reduction and internal fixation (ORIF) with plates and screws for plafond injuries caused by skiing initially reported by Ruedi and Allgower proved inadequate for the treatment of high-energy motor vehicle accident type injuries. The purpose of our study was to review our treatment protocol using a spanning external fixator placed semi-emergently medially across the joint and a later staged ORIF of just the articular surface to achieve and maintain anatomic reduction. METHODS: We preformed a retrospective study of 35 patients with 37 highly comminuted severe (OTA 43-B3 and -C3 or Ruedi type II or III) tibial plafond fractures treated by a single surgeon. All patients were treated with an initial spanning unilateral external fixator and subsequent ORIF. Radiographs were examined for: classification, number of pieces of the tibial dome, evidence of ground-glass comminution (more than three pieces <2mm in size on CT), anatomic reduction, alignment, and presence/absence of arthritis. RESULTS: Evidence of ground glass comminution existed in 26/37 patients (70%). Following ORIF, articular reduction was perfect (0-1mm displacement) in 29/36 (81%), imperfect (1-3mm) in 6/36 (17%) and poor (>3mm) in 1/36 (3%) cases. Joint alignment was anatomical in 35/37 (96%), with 15 degree anterior angulation in one patient and 5 degree valgus angulation in another patient. Radiographic arthritis was present in 10/36 patients (28%) at latest follow-up. Joint distraction at time of reduction was present in 27/37 patients (73%). A total of 25/37 patients (65%) had no post-operative complications, while 3/37 (8%) had a joint infection requiring one patient to have hardware removed. A total of 4/37 (11%) showed loss of reduction at latest follow-up. A total of 3/37 (8%) had a secondary arthrodesis; A total of 1 (3%) had a primary arthrodesis; 1 (3%) diabetic man had a below-knee amputation after a failed arthrodesis. DISCUSSION AND CONCLUSION: We treat severe tibial plafond fractures with a spanning external fixator at the time of injury, wait between 10 and 21 days to allow for soft tissue healing, and then perform a limited ORIF of the articular surface with canulated screws. In a group of high-energy plafond fractures, we achieved 81% good to excellent results with this protocol. We conclude that use of a spanning external fixator with delayed ORIF compares favorably with the literature.

Adult↗
PubMed1975

Fixation of foetal pig liver for electron microscopy. I. The effect of various aldehydrs and of delayed fixation.

Light and electron microscopic investigations of the ability of various fixatives to preserve foetal pig liver tissue (immersion fixed 5 min, 20 min, and 40 min after the death of the mother) gave the following results: 1) Fixation with 4% formaldehyde gives, in all circumstances, an unacceptable tissue presevation. 2)Fixation with 2.5% glutaraldehyde gives fair tissue preservation in a ca. 130 mu thick zone below the surface. 3) Fixation with a fixative mixture containing 2% formaldehyde and 1.25% glutaraldehyde or 2% formaldehyde, 1% glutaraldehyde and 1% acrolein gives good tissue preservation in a ca. 500 mu thick zone under the surface. 4) The addition of DMSO does not improve tissue preservation. 5) Delayed fixation of liver tissue removed from the foetus after the uterus has been placed in an incubator for 40 min has only a slight effect on tissue preservation.

Acrolein↗
PubMed1996

Fixation strength of interference screw fixation in bovine, young human, and elderly human cadaver knees: influence of insertion torque, tunnel-bone block gap, and interference.

A failure analysis of interference screw fixation was performed to test the hypothesis that bovine and/or elderly human cadavers are appropriate models for bone-patellar tendon-bone anterior cruciate ligament (ACL) reconstruction fixation studies. Failure mode is an important criterion for validating experimental models. The bovine, young human, and elderly human failure loads were 799 +/- 261 N, 655 +/- 186 N, and 382 +/- 118 N, respectively, and the failure modes were 75%, 69%, and 30% tissue failures, respectively. The similarities between the bovine and young human models in failure loads and failure modes indicate that bovine models are appropriate for ACL reconstruction fixation studies. The statistically significant differences between the young human and elderly human models in failure loads and failure modes indicate that elderly human cadavers are not an appropriate model for ACL reconstruction fixation studies. The differences in failure modes are consistent with previous studies using elderly human cadavers in which the predominant failure mode was bone block pullout. The tissue failures observed in the bovine and young human models contradict previous studies suggesting fixation strength is the weakest link in bone-patellar tendon-bone ACL reconstruction. Results of linear regression modeling showed statistically significant correlations between insertion torque and failure load (R2 = 0.44, P < 0.0001) and interference (defined as the screw outer thread diameter minus the tunnel-bone block gap) and insertion torque (R2 = 0.18, P = 0.003) when data from all models was combined. Results for the bovine model multiple regression showed a statistically significant regression of insertion torque (linear) and interference (quadritic) versus failure load (R2 = 0.56, P = 0.02). Regression slopes for screw diameter (P = 0.52) and gap size (P = 1.00) were not statistically significant. These results indicate that insertion torque and interference are independent predictors of failure load and should be included in future interference screw studies in addition to bone block dimensions, tunnel size, gap size, and screw diameter. Clinicians may consider using insertion torque and interference as indicators of postoperative graft fixation regarding rehabilitation decisions.

Adult↗
PubMed2003

Initial fixation strength of interference nail fixation for anterior cruciate ligament reconstruction with patellar tendon graft (experimental study).

The objective of this study was to evaluate initial fixation strength of a new interference nail fixation in anterior cruciate ligament reconstruction using bone-patellar tendon-bone graft. Human cadaver knees were used. Fixation strengths ranged from 500 N to 600 N (mean 550 N). This corresponds to loads in the graft during aggressive rehabilitation. No slippage occurred at fixation site of specimens. Most of the failures appeared from the femoral side with tendon ruptures. With respect to primary fixation strength, interference nail fixation is a reasonable alternative for anterior cruciate ligament reconstruction with bone-patellar tendon-bone graft.

Aged↗
PubMed2005

Cyclic loading comparison between biodegradable interference screw fixation and biodegradable double cross-pin fixation of human bone-patellar tendon-bone grafts.

PURPOSE: The aim of this study was to compare ultimate load, yield load, stiffness, and displacement after cyclic loading of a cross-pin technique and an interference screw technique for the fixation of bone-patellar tendon-bone (BPTB) grafts in anterior cruciate ligament (ACL) reconstruction. TYPE OF STUDY: Biomechanical in vitro study. METHODS: The devices tested were 2 2.7-mm biodegradable pins (RigidFix; Ethicon, Mitek Division, Norderstedt, Germany) and biodegradable interference screws (Absolute; Innovasive Devices, Marlborough, MA). Each device was used for the fixation of 10 8-mm, 9-mm, or 10-mm sized human BPTB grafts in tunnels drilled in bovine knees. Ultimate load, yield load, stiffness, and displacement after cyclic loading (1,000 cycles between 50 and 250 N) were then evaluated. RESULTS: All 8-mm grafts that were fixed with cross-pins failed after a mean of 124 cycles of load. The 9-mm and 10-mm grafts survived the cyclic loading protocol. Yield load and maximum load of the 10-mm groups (cross-pin and interference screw) were significantly higher than that of the 9-mm groups. There was no significant difference in maximum load, yield load, and stiffness between the cross-pin and interference screw fixation technique for 1 graft size. CONCLUSIONS: The biomechanical data suggest that femoral fixation of 9-mm and 10-mm BPTB grafts using 2.7-mm biodegradable cross-pins leads to primary stability that is comparable to that of biodegradable interference screws. Fixation of 8-mm BPTB grafts using 2.7-mm biodegradable cross-pins had poor results. CLINICAL RELEVANCE: The diameter of the bone block is the limiting factor for the final fixation strength and the cyclical survival when using cross-pins. We strongly recommend not using this technique for bone blocks smaller than 9 mm in diameter.

Absorbable Implants↗
PubMed2003

External fixation of the foot and ankle. Elective indications and techniques for external fixation in the midfoot.

Although external fixation is widely used for treatment of fractures, limb deformities, and bone lengthening; use of external devices is still evolving. Elective cases for treatment of the midfoot and published research on external fixation specifically for surgical treatment of midfoot pain and deformity are scarce. Indications for elective external fixation in the midfoot are limited because rigid internal fixation in this area is relatively easy and successful. This article discusses podiatric conditions that can be treated advantageously by external fixation when elective surgery is done. The article also describes methods of external fixation appropriate for podiatric surgical reconstruction in patients with these conditions.

Arthrodesis↗
PubMed1991

Interference screw fixation of cervical grafts: a biomechanical study of a new method of cervical fixation.

The dislodgement of anterior bone graft in the cervical spine is a frequent complication of attempted fusion following discectomy or corpectomy. It has been hypothesized that fixation augmented with interference screws may increase the pull-out strength of the construct and decrease the rate of these complications. Mechanical tests were conducted to compare interference screw fixation methods for enhancing the fixation between the bone graft and the adjacent vertebra. The anterior pull-out strengths of cervical bone grafts were compared using fixation with and without the addition of interference screws. Both discectomy and corpectomy graft models were examined in vitro. The mean pull-out force for a Smith-Robinson type bone graft alone was 58.1 N (SD +/- 11.4 N); for the graft augmented with two 3.5 mm cancellous bone screws, 153.9 N (+/- 58.9 N); for the graft with four 3.5 mm screws, 217.1 N (SD +/- 69.9 N). The pull-out strengths of the two and four 3.5 mm screw constructs were significantly greater than the strength of the graft alone (p less than 0.05). Similarly placed 2.7 mm cortical screws of the same length provided increased pull-out strength (123.7 N +/- 38.6 N and 142.5 N +/- 38.2 N for two and four screws, respectively); however, in comparison to the graft alone, these differences were not statistically significant. For both screw types, the four screw fixations were stronger than the two-screw fixations, although these differences were not statistically different.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Alfalfa root nodule carbon dioxide fixation : I. Association with nitrogen fixation and incorporation into amino acids.

In vivo CO(2) fixation activity and in vitro phosphoenolpyruvate carboxylase activity were demonstrated in effective and ineffective nodules of alfalfa (Medicago sativa L.) and in the nodules of four other legume species. Phosphoenolpyruvate carboxylase activity was greatly reduced in nodules from both host and bacterially conditioned ineffective alfalfa nodules as compared to effective alfalfa nodules.Forage harvest and nitrate application reduced both in vivo and in vitro CO(2) fixation activity. By day 11, forage harvest resulted in a 42% decline in in vitro nodule phosphoenolpyruvate carboxylase activity while treatment with either 40 or 80 kilograms nitrogen per hectare reduced activity by 65%. In vitro specific activity of phosphoenolpyruvate carboxylase and glutamate synthase were positively correlated with each other and both were positively correlated with acetylene reduction activity.The distribution of radioactivity in the nodules of control plants (unharvested, 0 kilograms nitrogen per hectare) averaged 73% into the organic acid and 27% into the amino acid fraction. In nodules from harvested plants treated with nitrate, near equal distribution of radioactivity was observed in the organic acid (52%) and amino acid (48%) fractions by day 8. Recovery to control distribution occurred only in those nodules whose in vitro phosphoenolpyruvate carboxylase activity recovered.The results demonstrate that CO(2) fixation is correlated with nitrogen fixation in alfalfa nodules. The maximum rate of CO(2) fixation for attached and detached alfalfa nodules at low CO(2) concentrations (0.13-0.38% CO(2)) were 18.3 and 4.9 nanomoles per hour per milligram dry weight, respectively. Nodule CO(2) fixation was estimated to provide 25% of the carbon required for assimilation of symbiotically fixed nitrogen in alfalfa.

Journal Article↗
PubMed2005

Screw fixation compared to H-locking plate fixation for first metatarsocuneiform arthrodesis: a biomechanical study.

BACKGROUND: Several different techniques have been used for fixation of first metatarsocuneiform (MTC) joint arthrodesis, a standard treatment for arthritis, instability, and deformity of the MTC joint. Improved plating systems using locking designs are now available, but no studies have yet compared this construct with other methods. We compared load to failure with a locking plate design versus standard crossed-screw fixation. METHODS: Ten matched pairs of fresh frozen cadaver feet were used. The bone density of each pair was measured with DEXA scanning. One foot of each pair was randomly assigned to have a dorsomedial Normed H titanium locking plate (Normed Medizin-Technik Vertriebs-GmbH, D-78501 Tuttlingen, Germany) applied to the first MTC joint. On the other foot of the pair, fixation of the first MTC joint was done with crossed ACE DePuy 4.0 (DePuy/Ace, Warsaw, IN) titanium cannulated screws. The first metatarsal and first cuneiform were then isolated and planted in an epoxy resin. The specimens were loaded to failure in a four-point bending configuration using a MTS Mini Bionix test frame (MTS Systems Corp., Eden Prairie, MN). Failure was defined as displacement of more than 3 mm at the arthrodesis site. The Student t-test was used to determine any observed differences, with significance set at p <or= 0.05. RESULTS: The mean maximal load to failure was 140.08 N (SD +/- 77.1) for screw fixation alone and 58.09 N (SD +/- 11.86) for the H-locking plate. This difference was statistically significant (p = 0.008). The mean stiffness of the construct for screw fixation alone was 83.10 N/mm (SD +/- 49.8) and 19.96 N/mm for the H-locking plate. This difference also was statistically significant (p = 0.004). CONCLUSION: Screw fixation for first MTC arthrodesis created a stronger and stiffer construct than did the H-locking plate. This was likely due to the mechanical design of the implants. Compression across the MTC joint could be applied with the screws, but the plate relied on a fixed angle design with no compression.

Arthrodesis↗