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Three-dimensional dynamic AO external fixation of distal radial fractures--a preliminary report.

External fixation of unstable and intra-articular distal radial fractures has become increasingly popular. Dynamic external fixation, allowing movement of the wrist during the fixation period, is a relatively new approach which may further improve functional end results. To permit early functional treatment, the small AO external fixator was supplemented by a joint allowing all three degrees of rotational freedom. The centre of rotation is located at a point outside the device and lies approximately in the head of the capitate. With the natural centre of wrist rotation coincident with that of the fixator, admissable movements of the wrist include both flexion-extension and radio-ulnar deviation, without threatening fracture reduction. In vitro testing and initial clinical experience with a prototype are encouraging. Several improvements of the original design have been made and a multicentric clinical study is scheduled for further evaluation of the new dynamic external fixator.

Adult↗

[Single-plane external fixation of fresh fractures of the femur: critical analysis of 53 cases].

PURPOSE OF THE STUDY: External fixation has not been widely used for femoral fractures and few series are reported in the literature. External fixation is generally reserved for severe open fractures, for vessel injury or multiple trauma with life threatening. We present a retrospective analysis of a serie treated in a single center in order to detail the indications of this fixation technique. MATERIAL AND METHODS: From 1984 to Jun 2002, 49 patients with femoral fractures were treated by external fixation. The series included 36 men and 13 women, mean age 31 years. All were victims of high-energy trauma: traffic accident (n = 40), fall from high level (n = 4), firearm wound (n = 5). Multiple fractures were present in all patients except seven and 24 patients had multiple injuries. Forty fractures were open fractures: two type 1, ten type 2, four type 3a, 23 type 3b and five type 3c in the Gustilo classification. Twenty-seven were shaft fractures and 26 involved the distal metaphyseoepiphyseal portion of the femur. Loss of cortical stock was noted in five cases and total loss of a segment in four. Surgery was deferred in 19 patients, mean six days. A single-plane external fixation was used (Orthofix) with a femorofemoral frontolatateral assembly. Transepiphyseal screw fixation was also used to stabilize the distal fracture in eleven cases. RESULTS: One patient with a bifocal fracture of the femur died from head trauma. Three patients required above knee amputation after failure of a vessel bypass or due to septic necrosis of the reconstruction flap. Five patients required a second reduction within days of external fixation. On the AP view, femoral alignment was successfully reestablished at +/- 5 degrees in 45 cases, ranged from 5 degrees to 10 degrees in seven and was greater than 10 degrees in one. On the lateral view, alignment was between 5 degrees and 10 degrees in 42 cases and greater than 10 degrees in one. Femur length was equal to the healthy side in 23 cases, and was shortened 1-2 cm in 26. Four metaphyseal fractures resulted in a 3 cm shortening. Bone healing time was available for 42 patients (1 death, 3 amputations, 3 lost to follow-up). Elective conversion to internal fixation was performed in ten patients (five lateral cortical plates and five centromedullary nailings). These patients all achieved first-intention bone healing with a mean time of 7.4 months. Exclusive external fixation was planned for 34 fractures. First-intention healing was achieved in 25 (17 shaft and 8 distal) without bone graft with an average time of 7.3 months. Ten patients had one or more osteitis foci on pin tracts. Two patients in this group developed recurrent fracture after removal of the external fixator. Nine fractures did not heal and required revision with centromedullary nailing (n = 5) or plate fixation with autograft (n = 4). Nailings for nonunion were successful but plate fixation was compromised by infection in one patient and recurrent fracture after plate removal in another. Fourteen patients underwent joint mobilization under general anesthesia and 14 had open arthrolysis. Mean follow-up was 2.8 years. Mean active flexion was 90 degrees (30-130 degrees). Ten patients exhibited flexion between 30 degrees and 60 degrees and 19 between 70 degrees and 100 degrees. Knee flexion was greater than 110 degrees in 15 patients. Residual 10 degrees flexion was noted in six knees. Mean leg length discrepancy was 0.4 +/- 0.6 after distal fracture and 0.8 +/- 1.3 after diaphyseal fracture. DISCUSSION: The indications and results of external fixation in this series are in line with reports in the literature. For diaphyseal fractures, healing is long and difficult, partly because of the insufficient mechanical properties of external fixation. The rate of infection and stiff knee is high, particularly for distal fractures of the femur. CONCLUSION: External fixation remains the only solution to stabilize certain open diaphyseal fractures or for patients with life-threatening multiple injuries. This techniques allows control of the other traumatic lesions while waiting for internal fixation. For fractures of the distal femur, external fixation can only be advocated for metaphyseodiaphyseal fractures with an intact or reconstructed epiphyseal portion.

Adolescent↗

Slow, gradual external fixator distraction in acquired ankle and foot contracture.

BACKGROUND: External fixators have been noted to have a place in the orthopaedic management of problems involving the ankle and foot. We here report a case of ankle and foot contracture managed by soft tissue release and slow, gradual external fixator distraction. METHOD: A case report of a patient with acquired ankle and foot contracture and discussion of relevant literature. RESULTS: A 9-year old female presented to our out-patient clinic with features of right ankle and foot contracture following treatment by traditional bone setters 6 years earlier. The contracture was fixed at 30 degrees. She had soft tissue release and slow, gradual external fixator distraction which corrected the foot to a plantigrade position. Subsequently she had skin grafting for the skin defect. After removal of the external fixator she was placed on a below knee cast and commenced weight bearing. The cast was removed after three weeks and the patient has continued to bear weight on a plantigrade foot. CONCLUSION: External fixators have a definite place in contracture release and should be widely utilized.

Ankle Injuries↗

External fixation for open fractures of the upper extremity.

Recent advances in external fixation hardware, frame application, and pin-site care have resulted in the evolution of external fixation as a safe and versatile technique. It provides skeletal stability, access to the site of injury, and allows early mobilization. It avoids the disadvantages of additional soft-tissue stripping and the foreign body introduction associated with internal fixation of open fractures. The utility of external fixation principles in open hand and wrist fractures is well established. Indications for external fixation in open fractures of the forearm, elbow, and arm are more restricted. External fixation in these locations should probably be limited to situations of marked fracture comminution, bone loss, or extensive soft-tissue damage.

Arm Injuries↗

Immediate external fixation of unstable pelvic fractures.

Immediate external fixation has been proposed as a means of stabilizing severe pelvic fractures to reduce the chance of organ failure and death. Sixty-six patients were admitted from January 1980 through December 1983 with double fractures of the pelvic ring that involved the posterior elements. Twenty-six patients (39 percent) underwent immediate external fixation for instability, and 40 patients (61 percent) with stable fractures were treated with bed rest. The two groups were similar in age, injury severity score, and degree of shock. The mortality rate of the two groups was the same (12 percent), as was the incidence of organ failure. The mean transfusion requirement in the unstable group was greater, but not significantly. Our results were better than those reported in recent studies in which immediate rigid fixation was not used. We conclude that the patient with multiple trauma without unstable pelvic fracture should undergo immediate external fixation to decrease morbidity and mortality rates and limit soft tissue damage.

Adult↗

[Progressive limb lengthening with a centromedullary nail versus an external fixator: experimental study in sheep].

PURPOSE OF THE STUDY: Progressive limb lengthening with an external fixator often leads to pin-related complications. A new technique allowing progressive lengthening with a centromedullary nail without external fixation has been developed. This original double-locked device consists of matching male and female components fitted with a continuous thread. Lengthening is achieved via a one-way ratchet system. Twelve back-and-forth movements produce 1.25 mm lengthening. MATERIAL AND METHODS: We tested this new device on 20 sheep and compared results with external fixation lengthening in 20 other sheep. The animals were divided into groups for sacrifice on days 5, 10, 20, 45 and 90. Serial x-ray were obtained for all animals. In the 45-day and 90-day groups, histomorphometric (trichrome goldner coloration and polarized light microscopy) and densitometric studies were also performed. Bone mineral density (BMD) was determined and bone trabecular density (BTD) and trabecular bone volume (TBV) were expressed in percent of bone trabecular surface area. RESULTS: Mean lengthening in the 45-day and 90-day groups was 39 mm for the nail and 20 mm for external fixation (1 mm/day). At 90 days, 3 sheep out of 4 had consolidated radiologically with external fixation and 2 out of 4 with the nail. BMD was slightly better for external fixation (0.811 vs 0.695/cm(2)). This difference could probably be attributed to the greater lengthening obtained with the nail. At 45 days, BMD was the same (0.6 g/cm(2)) for both devices. BTD was nearly two-fold higher for the nail compared with external fixation (59.65% vs 32.61% at 90 days), most probably due to primary bone formation. The histomorphometric study allowed an analysis of the osteoid border. Bone quality obtained in the bone regenerate with the nail was superior to that obtained with external fixation. Primary bone formation resulted from membrane ossification with direct transformation of fibroblasts into osteoblasts. CONCLUSION: This work demonstrated that progressive lengthening can be achieved with a specifically designed centromedullary nail without iterative opening of the operative site. Tolerance to this type of device and quality of the bone regenerate are altogether satisfactory.

Absorptiometry, Photon↗

[Strain gauge measurements on a one-side external fixation: a prospective series of 11 tibial shaft fractures].

PURPOSE OF THE STUDY: External fixation is often the treatment of choice for open complex fractures of the tibia. For closed tibial shaft fractures, it is generally a second choice alternative. The purpose of this study was to determine whether fusion of closed and open fractures of the tibia can be successfully achieved with a one-side external fixator equipped with strain gauges and to evaluate complications of this type of treatment. MATERIAL AND METHODS: A consecutive series of 11 mid shaft fractures of the tibia (4 closed fractures and 7 Gustilo grade I and II open fractures) in 11 patients (mean age 29 years) were treated with a one-side external fixator. Strain was measured weekly to adjust the treatment. A Sarmiento walking cast was applied in all cases 4 weeks after removal of the external fixator. RESULTS: All 11 fractures healed without complications and without pin tract infection. Mean delay to consolidation was 20.5 weeks (range 13 - 29.5 weeks). One patient required a revision procedure for decortication and bone graft at 12 weeks. Weight bearing (50% of body weight on the injured limb) was achieved at 6.7 weeks (mean) and total weight bearing at 11.9 weeks. The external fixator's strain curves were compatible with normal healing in 3 cases, with slow healing in 3 and with retarded healing in 3 others. Two of the curves did not show recognizable patterns despite a favorable clinical and radiological course to healing. DISCUSSION: Early detection of a pathological pattern of fracture healing followed with a strain gauge enabled adaptation of treatment in all cases. Decortication with bone grafting was necessary in one patient. In two other cases, compression of the fracture with the external fixator or dynamic locking were sufficient to achieve a favorable healing pattern. This small series demonstrated that bone healing can be achieved within usual delays with external fixation and without major complications. Use of strain gauges on the external fixator allowed early detection of retarded healing and subsequent modification of the treatment protocol. This type of treatment might be an interesting therapeutic alternative for the treatment of closed fractures of the tibial shaft.

Adult↗

Influence of an interdental full pin on stability of an acrylic external fixator for rostral mandibular fractures in dogs.

OBJECTIVE: To determine total stiffness and gap stiffness of an external fixation system in a canine mandibular fracture gap model incorporating a full interdental pin as the only point of rostral fixation in a bilateral type-I external fixator. SAMPLE POPULATION: 10 canine mandibles. PROCEDURE: Bilateral mandibular ostectomies were performed between premolars 3 and 4. A type-I external fixator incorporating a full interdental pin was placed to stabilize a 0.5-cm fracture gap. Four pin configurations (intact mandibular bodies with fixator; ostectomized mandibular bodies and complete fixator; ostectomized mandibular bodies with caudal pins of rostral fragment cut; ostectomized mandibular bodies with all pins of rostral fragment cut) were tested in dorsoventral bending 5 times on each mandible. The full interdental pin remained intact in all configurations. Total stiffness and gap stiffness were determined for each configuration on a materials testing machine. RESULTS: Total stiffness of intact mandibles was significantly greater than that of ostectomized mandibles, regardless of external fixator configuration. However, total stiffness and gap stiffness were not significantly different among different external fixator configurations applied to ostectomized mandibles. CONCLUSION AND CLINICAL RELEVANCE: External fixator configurations with only the full interdental pin engaging the rostral fragment were as stiff as configurations that had 2 or 4 additional pins in the rostral fragment for the applied loads. External fixators for rostral mandibular fractures may be rigidly secured with rostral fragment implants applied extracortically, avoiding iatrogenic trauma to teeth and tooth roots.

Animals↗

Treatment of hand injuries by external fixation.

Thirty-five consecutive applications of external fixation to the hand, including 27 acute cases and 8 reconstructive procedures, were studied. In both settings, external fixation was used not only for skeletal stabilization but also for management of the soft tissues. Twenty of the 22 acute fractures healed, and six arthrodeses with interposition bone grafts resulted in fusion. Three septic nonunions resolved, and two united successfully. There were no complications. We recommend external fixation systems in the hand, and several case reports are included in the study to illustrate the various applications.

Adolescent↗

Pearls and pitfalls of deformity correction and limb lengthening via monolateral external fixation.

In conclusion, monolateral external fixation can be effectively utilized in the management of limb length discrepancy and angular deformity. This manuscript outlines the pertinent theory, application and problems important in these cases. When faced with specific congenital conditions the surgeon is encouraged to reference relevant literature that is more focused than the current paper.

Biomechanical Phenomena↗

[Rare indications for an external fixator].

Seldom indications for the use of external fixator are reported and illustrated. As a rule the damage to the pelvis is complex and it is often associated with a polytrauma; unstable pelvis injuries in some cases can be stabilised by external fixator by the method of Slätis. Examples of osteotaxis are given for the treatment of comminuted fractures or defect-pseudarthroses or after osteomyelitic bone damage of femur and humerus. In the treatment of multi-fragment fractures of the base of the radius and of the forearm the external fixation can also be used with good success. The external mini-fixator is a new way for external stabilization in hand surgery and can provide good results in comminuted fractures of the fingers and for finger-replantation.

Adolescent↗

Treatment of distal femoral nonunions by external fixation with simultaneous length and alignment correction.

The use of external fixation for management of distal femoral nonunions may minimise some of the problems frequently encountered in these patients. Fifteen patients treated by external fixation for distal femoral nonunions between 1987 and 1997 were reviewed. There were nine males and six females. The average age was 35.4 years (17-53) with an average follow up of 4.6 years (2-8). Nine followed an open fracture, five a closed fracture and one a femoral osteotomy. Five of the cases were infected nonunions. In all cases an internal fixation device was used as the initial method of treatment. All patients had the nonunion site stabilised with an external fixator. In 12 cases the knee joint was crossed with the fixator to further stabilise the fracture site. All patients had some degree of leg length discrepancy or malalignment that required correction. Fourteen cases united. The other patient united following intramedullary nailing. The average time to union was 10.4 months (4-24). The average range of movement was 80 degrees after treatment. Up to 9 cm of lengthening was achieved using the external fixation system (mean 5.0 cm). The mean angular correction was 15 degrees. One patient had persistent pain despite union at the time of the last follow up. The advantages of preservation of soft tissue, immobilisation of the fracture site by crossing the knee joint and the facility for proximal lengthening make external fixation a definite option in the management of distal femoral nonunions.

Adolescent↗

Arthroscopic debridement of external fixator pin tracts.

Major external fixator pin tract infection can be managed by curettage, overdrilling or excision of the pin tract. An alternative is arthroscopic debridement which allows thorough curettage with the advantage of direct inspection of the pin tract to ensure clearance of all necrotic tissue from the tract base and walls. To date, arthroscopic pin tract debridement has been used successfully to manage 25 pin tracts in six patients. Adequate visualization of the pin tract throughout its course was possible in all cases. Two patients subsequently underwent intramedullary nailing without complication. No recurrent infection has occurred at review at 13 months.

Arthroscopy↗

Antimicrobial efficacy of external fixator pins coated with a lipid stabilized hydroxyapatite/chlorhexidine complex to prevent pin tract infection in a goat model.

BACKGROUND: Pin tract infection is a common complication of external fixation. An antiinfective external fixator pin might help to reduce the incidence of pin tract infection and improve pin fixation. METHODS: Stainless steel and titanium external fixator pins, with and without a lipid stabilized hydroxyapatite/chlorhexidine coating, were evaluated in a goat model. Two pins contaminated with an identifiable Staphylococcus aureus strain were inserted into each tibia of 12 goats. The pin sites were examined daily. On day 14, the animals were killed, and the pin tips cultured. Insertion and extraction torques were measured. RESULTS: Infection developed in 100% of uncoated pins, whereas coated pins demonstrated 4.2% infected, 12.5% colonized, and the remainder, 83.3%, had no growth (p < 0.01). Pin coating decreased the percent loss of fixation torque over uncoated pins (p = 0.04). CONCLUSION: These results demonstrate that the lipid stabilized hydroxyapatite/chlorhexidine coating was successful in decreasing infection and improving fixation of external fixator pins.

Animals↗

Design and testing of external fixator bone screws.

In external fixation, bone screw loosening still presents a major clinical problem. For this study, the design factors influencing the mechanics of the bone-screw interface were analysed and various experimental screws designed with the intention of maximizing the strength and stiffness of the inserted screw. Push-in, pull-out and bending tests were then carried out on the three experimental screws, and on two commercially available screws in both a synthetic material and in cadaveric bone; photoelastic tests on different screw threadforms were also performed. The results of the push-in and pull-out tests indicate that both the screw threadform and cutting head have a significant effect on the holding strength of the screw. The photoelastic tests show that most of the applied load is distributed over the first few threads closest to the load, and that the area between the thread crests is subjected to high shear stresses.

Biomechanical Phenomena↗

Comparison of crossed pins and external fixation for correction of angular deformities about the knee in children.

External fixation was compared to crossed Steinman pins and plaster for fixation after osteotomy about the knee in children. A group of 26 patients treated by external fixation was compared to a control group of 26 patients fixed with crossed Steinman pins and casting. The groups were matched for age, height, and weight. Overall there was a 100% union rate. Preoperative deformity and postoperative correction were similar in the two groups. The time to union was significantly longer, and there were significantly more complications in the external fixator group. There were 16 complications (62%) in the external fixator group and five (19%) in the control group. Complications included pin tract infections, peroneal nerve palsy, and delayed union. External fixation provides certain advantages for fixation after osteotomies about the knee in children but is associated with a variety of complications.

Adolescent↗

The effectiveness of standard povidone iodine surgical preparation in decontaminating external fixator components.

The purpose of this study was to evaluate the effectiveness of standard iodine surgical scrubs to remove bacteria from external fixator components. Sterile adjustable external fixation clamps, Schanz pins, and carbon fibre rods were coated with a sterile protein solution and immersed in solution of coagulase negative Staphylococcus (10(3)organisms/ml). They were then decontaminated in standard fashion using a povidone iodine scrub and paint solution. After neutralisation the components were sonicated, serially diluted, plated on blood agar, and incubated for 24h. Unassembled external fixation components were examined individually, and as assembled pin-rod-clamp constructs with and without manipulation of the clamp. Of the three external fixation components (pins, rods, clamps) the highest number of bacterial colony forming units was seen on the external fixation clamps. Manipulation of the assembled construct significantly increased the mean bacterial colony counts compared to the assembled non-manipulated construct (p=0.0007). Standard surgical preparation does not remove all bacteria from external fixators during subsequent operative procedures.

Anti-Infective Agents, Local↗

In vitro comparison between a DCP and external fixator for pancarpal arthrodesis in the dog.

Many clinical reports have previously documented the advantages of plates or external fixations but surgeons prefer to use plate for better acceptance by the owner, less dressing and a decreased rate of infection. In order to address complications of carpal surgery, infections, arthritis and osteomyelitis, external fixation is warranted. Twelve canine forelimbs, free of abnormality, were tested under compression to evaluate the in vitro biomechanical behaviour of the normal carpus. This behaviour was compared with that of a stabilized carpus stabilised by panarthrodesis with either plates (8 hole 3.5 mm dynamic compression plate (DCP), or a type II external fixator. Deformation vs. load was recorded after compression with a testing machine in conjunction with a digital data acquisition system. Yield load, maximal load to failure and stiffness were then calculated. Variables were significantly greater for arthrodesis with external fixation and plates than for intact forelimbs. The stiffness and the MLF after stabilisation with plates or external fixators did not differ significantly. At MLF, fracture of the third metacarpus appeared with plates, whereas deformations of the pins and bars of the external fixators increased with load. Stabilisation with plate or external fixation allowed more load to failure than the intact carpus. The biomechanical behaviour of both methods of arthrodesis was identical during loading. However, after rupture, external fixation was more plastic. External fixation, which is less often used than plates for pancarpal arthrodesis, mainly due to the occurrence of sepsis, may be useful for arthrodesis of the carpus in big or active dogs.

Animals↗