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We report six cases of delayed union of fractures of the shaft of the tibia treated by the application of an external fixator on a day case basis. All fractures united within 12 weeks.
We immobilised the right hindlimbs of six-month-old female Wistar rats for four weeks using a biplanar external fixation bridging the knee. The untreated left limbs served as a control group. An additional group of rats was allowed to recover for four weeks after removal of the frame. Immobilisation caused reduction in the wet weights of approximately 50% in the gastrocnemius, quadriceps, soleus and plantaris muscles; this was not restored completely after remobilisation. There was an increase in the activity of acid phosphatase of approximately 85% in the gastrocnemius and quadriceps muscles whereas that of creatine phosphokinase was reduced by about 40%. These values returned to nearly normal after remobilisation. Histological and ultrastructural examination showed a marked myopathy of the gastrocnemius muscle after immobilisation although the morphology was largely restored after remobilisation. We conclude that after four weeks of remobilisation, hind-limb muscles do not return to preimmobilisation weights, although biochemical activities and ultrastructural appearance are largely restored.
From 1992 to 1994, 37 fractures (36 patients) were treated with hybrid external fixation for tibial plafond or distal tibial fractures. The fractures were classified according to the AO classification: A1 (3), A2 (3), A3 (4), C1 (6), C2 (12), C3 (9). There were 11 open injuries, and in 27 patients (75%) the mechanism of injury was high energy trauma. Results were evaluated based on a subjective and objective rating system. Thirty-four patients were available for followup at an average of 15.2 months. All fractures in this series united with an average time to healing of 4.6 months. Anatomic or good alignment was obtained in all but 1 fracture. There were 12 excellent, 9 good, 7 fair, and 6 poor results. In the 18 C2 and C3 fractures there were 8 good to excellent, 4 fair, and 6 poor results. Degenerative changes were seen on followup radiographs in 4 of these patients. Complications occurred in 12 patients (35%) and included 1 skin slough, 5 pin tract infections, 3 deep infections, 3 nonunions, and 3 loss of reductions necessitating frame revision. This method yielded results comparable with previous studies while decreasing the number of complications resulting from treatment.
With the type of external bone anchorage made from metal and usually employed in Germany, Austria and Switzerland, the considerable weight of such anchorages and their imperviousness to X-rays are major drawbacks. For this reason, the prototype of an external fixation agent was developed which does not posses these disadvantages. Fibre-reinforced polymeric materials appeared a suitable alternative to metal. Satisfactory strength of the components of the system could be expected provided the anchoring was suitably constructed. External bone anchorage with polymer materials is easy to manipulate, transparent to X-rays, sterilisable, and possesses dimenisonal stability to head. The weight reduction amounts to as much as 70%. A multitude of variants can be mounted from just four system components. Economic manufacture is possible through material-specific processing (injection moulding, machining).
Septic arthritis as a result of pin track infection, following application of external fixators in periarticular fractures of the lower limb, is a rare, but serious complication. Several studies, combining cadaver dissection and MRI scans or conventional X-ray measurements, have tried to define the exact anatomy of the capsular reflection in the major joints of the lower limb (hip, knee and ankle), in order to provide specific safe corridors for extra-capsular wire and pin placement. These studies are reviewed, their methods and results are presented, and their conclusions are evaluated as suggested guidelines for safe extra-capsular wire and pin insertion.
Authors report the results they obtained when the Ilizarov circular external fixator was used for the treatment of post-traumatic nonunion of the tibia. A total of 20 patients were treated. Of these 12 had been submitted to treatment elsewhere and using other methods; 9 presented with septic nonunion; 10 revealed radiographic findings of atrophic nonunion, and 10 were hypertrophic. There was axial deviation in 18 patients. The results of treatment were always: healing of the nonunion; functional recovery of the limb; correction of leg length discrepancy; recovery of the mechanical axis. The mean stabilization time (days between the application and the removal of the fixator) was 138 days. The Ilizarov method thus proved that it was effective in the treatment of post-traumatic nonunion of the tibia where other types of treatment had failed.
OBJECTIVE: To measure changes in knee kinematics after the application of articulated external fixators along a previously described knee flexion/extension axis and 16 specific "off-axis" fixator hinge configurations. DESIGN: Cadaver, biomechanical study. SETTING: Biomechanics laboratory. PARTICIPANTS: Nine fresh cadaver knee specimens. INTERVENTION: Each specimen was mounted on a custom-built frame that constrained the knee to move about a fixed flexion/extension axis. Passive knee motion was induced, and the resulting flexion moment was measured. Data were collected for the on-axis fixator position and 16 distinct rotational and translational off-axis positions. In addition, effects of tibial translation and rotation were investigated. MAIN OUTCOME: Range of motion (ROM) attainable within a moment envelope of +/-1 N-m and average energy required to impart movement. RESULTS: The average ROM for unconstrained knees was 122 degree. Constraining the knee to rotation around an on-axis aligned hinge significantly reduced the ROM by 35% to 79 degree. The 5-mm posterior translated hinge was the only alignment to show on average a slightly larger ROM (86 degree) than the on-axis hinge. All other hinge alignments showed decreased average ROM compared with the on-axis position. Tibiofemoral alignments significantly affected the obtainable ROM for the on-axis aligned hinge. CONCLUSION: It was not possible to replicate precisely the complex kinematics of the knee using a single axis fixator over the entire ROM. Using the axis of rotation previously defined in the literature, however, it was possible to obtain a limited ROM of the knee without placing excessive forces on the periarticular structures.
We compared Norian SRS, an injectable calcium phosphate bone cement, with external fixation in the treatment of redisplaced distal radial fractures by a prospective randomized study in 40 patients (women 50-80 years or men 60-80 years). After rereduction, the fracture was either stabilized by injection of SRS and immobilized with a cast for 2 weeks, or externally fixed with Hoffman's bar for 5 weeks. Each patient was evaluated at 2, 5, 7 weeks and at 3, 6 and 12 months. Functional parameters were grip strength, range of motion and pain. Radiographic parameters were radial angle, ulnar variance and dorsal tilt. The chosen primary effect variable was grip strength at 7 weeks. Patients treated by injection of SRS apatite had better grip strength, wrist extension and forearm supination at 7 weeks. There was no difference in functional parameters at 3 months or later. None of the methods could fully stabilize the fracture: radiographs showed a progressive redislocation over time. The results indicate that SRS can be used in the treatment of unstable distal radial fractures. The more rapid recovery of grip strength and wrist mobility in the SRS group appears to be due to the shorter immobilization time.
Seven patients with Frykman type 7 and 8 distal radial fractures, who had been treated with external fixation, were noted to have significant over-distraction of 5-8 mm in the radio-carpal and mid-carpal joints. One patient, who also had abnormal negative ulnar variance of 2 mm, had a fair result using modified Gartland and Werly (1951) criteria. The remaining six patients had good results, indicating that over-distraction does not significantly alter the final outcome, so long as a normal distal radio-ulnar relationship is maintained.
Malunion is often a problem in adolescent femoral shaft fractures treated with traction and subsequent casting. We used external fixation as an alternative treatment method to control alignment and allow early mobilization. After fracture healing and fixator removal, two patients experienced refracture. This unusual complication is the basis of our report. Prolonged rigid or static fixation appears to be detrimental to sufficient callus formation and healing.
The authors reviewed 31 distal tibial fractures (16 involving the tibial plafond) treated with Ilizarov external fixation. The study population was composed of 19 males and 12 females, with an average age of 54. The fractures were classified according to the AO classification: A1 (3), A2 (6), A3 (6), C1 (2), C2 (8), C3 (6). There were six open injuries. In 14 pilon cases, open reduction of the intra-articular fragments and bone grafting via a limited incision was performed. Clinical follow-up averaged 28 months (range 18-42). All but one fracture united with an average healing time of 13.9 weeks. Nearly all patients with AO type A fracture had excellent or good functional scores. The 14 cases of AO C2 and C3 group had five (38%) good results, five (38%) fair results and three (24%) poor results. This method yielded results comparable with previous studies using open reduction and internal fixation. Twenty-nine percent of the patients had pin track infection, which remained the most important complication of this method.
A mini fixator system was used to assist the operative correction of soft-tissue flexion contractures. The external fixator served as a tool for gradual correction and to secure joint position after soft-tissue release. Following wound healing, certain fixator components were unlocked and joint mobilisation initiated. Correction involved a contraction of the first web-space as well as flexion contractures of the index, middle, ring, and small fingers. The fixators were removed after four to six weeks. Complications related to the fixator equipment were not observed. The spread from thumb to index finger tip was increased from 3.5 to 16.5 cm. The functional result in sustained grip strength reached a value of 82% compared to the uninjured opposite side.
A case of open carpal dislocation fracture not previously described is reported on. Reduction and stabilization of the dislocation were successfully performed using external fixation without additional Kirschner wires. Despite extensive trauma, hand function is now excellent, and there are no signs of residual carpal instability.
The objective of the current study was to evaluate the stabilization of a simulated juxta-articular bone segment with a circular external fixator, and to determine which method of fixation improved bending stabilization while preserving the axial dynamization of a three-wire configuration. Frames were divided into three groups: wire, half-pin and hybrid and tested in axial compression, torsion, anteroposterior bending and mediolateral bending. Hybrid frames using 4 mm half-pins improved the anteroposterior stabilization of the short bone segment while maintaining axial characteristics similar to a three-wire frame. Increasing the bending stabilization will improve bone segment alignment while permitting axial micromotion beneficial to bone healing.
From 1977 to 1987, 1033 cases of unstable tibio-fibular fractures were treated with an external fixator designed by the authors. Among them, 232 involved open fractures. All of the patients were followed up for 4 to 90 months (average 20 months). The duration of bed confinement averaged 8.3 days, and the mean time necessary for clinical bone union was 54 days. Anatomical or nearly anatomical bone apposition was effected in 878 cases (85.0%), functional apposition in 141 cases (13.6%) and malunion in 14 cases (1.4%). The overall functional results were as follows: excellent in 769 cases (74.4%), good in 218 cases (21.1%), fair in 32 cases (3.1%), and poor in 14 cases (1.4%). The design of the device and its indications are also discussed.
A simple and versatile method for external fixation of fractures of long bones is described. The method was first used in 1976 in a successful attempt to save a limb which had sustained a severe comminuted fracture of the tibia with vascular impairment.
The stresses generated at the pin-bone interface by external fixator pins have been compared using finite element analysis. The results show that higher stresses are generated by conical pins compared with standard pins of the same diameter. This raises the possibility that the rate of pin loosening may be higher for conical pins.
A fast, simple and always available low cost external fixation device, made of two parallel plastic tubes and transverse Kirschner wires was devised and clinically tested.