External Fixation Techniques Research Articles

High-Energy Fractures of the Tibial Plateau

High-energy tibial plateau fractures are often the result of blunt trauma. In addition to extensive bony injuries, soft-tissue problems are very common. Preoperative planning for surgical repair of these injuries is invaluable. Contemporary internal fixation techniques using ligamentotaxis, percutaneous fixation, and antiglide techniques provide the basis for internal fixation of these injuries. When extensive comminution and damaged soft tissues prohibit their use, the circular external fixator provides an excellent option for management of these complex injuries. Whether internal or external fixation techniques are used, appropriate management of the soft tissues is also a factor in the successful management of these severe injuries to the knee.

The response of bone to external loading regimens

The results of Hert et al. 1 have been re-examined using an external pin fixation technique involving New Zealand White rabbits. New bone formation was assessed with tetracycline epifluorescence in 49 animals. The animals were operated upon using inhalational anaesthesia, and pins were placed at opposite ends of the tibia of both hind limbs. Following recovery, oxytetracycline was given at a dosage of 25 mg kg −1 body weight intraperitoneally on the day of loading and on the fourteenth day of the loading regimen. The bones were loaded for 45 min per 24 h. Undemineralized specimens were sectioned and standardized photographs produced. The area of new bone was determined by a planimeter and by digitization. In dynamic loading the shape of the force/time curve is of little significance; the response is frequency dependent and for higher frequencies the response is greater than that from continuous loading; there was no statistical significance between the rapid relief loading regimens. For continuous loading the response is a function of the load value. In all cases more bone is laid down in immature subjects than in adults. With regard to osteoclastic activity, all loading increased the areas of resorption irrespective of character, in all adult animals intermittent loads produced a greater area of ostoeclastic resorption than static loads and produced a greater change as the number of load cycles per minute increased. The adult control animals had more resorptive activity than the immature animals although there was no statistical significance. Loading, irrespective of its character, led to a net increase of bone, the osteoblastic effects thus outweighing the osteoclastic effects.

TECHNIQUE AND RESULTS OF EXTERNAL FIXATION OF COMPLEX CARPAL INJURIES

This article reviews the current indications and technique of external fixation of the wrist for complex carpal trauma. The results obtained in 24 consecutive patients with an average follow-up of 2.4 years are also presented.

The Cross-Leg Flap Revisited

Although free flaps are currently the gold standard for distal lower extremity reconstruction, situations occasionally arise when alternative methods are needed. We present three cases of cross-leg flaps, which have been modernized with current external fixation technology and current understanding of vascular anatomy. All cross-leg flaps were based on the axial blood supply of the posterior descending subfascial cutaneous branch of the popliteal artery. This axial flap afforded considerable length and well-vascularized tissue. All patients were placed in external fixation devices. Adjacent lower extremity joints were exercised during the period of attachment. There were no major complications or flap failures. All patients were ambulatory postoperatively. We conclude that the cross-leg flap, using external fixation techniques and axially based flaps, can be successfully and expeditiously used to cover defects of the lower extremities.

Knee, lower leg, foot, and ankle disorders in children.

The literature of the past year increased our understanding of the etiology of some common lower leg disorders in children, and increased our knowledge about the results and complications of some old and new treatment methods. Histochemical and vascular studies and magnetic resonance imaging were used to study the etiology and treatment of congenital clubfoot. Results of early intervention protocols and the ilizarov method were reported. Undercorrection at primary surgery was identified as a major reason for reoperation. Excision of the coalition with interposition of fat or tendon produced good results in selected children with middle facet talocalcaneal coalition. A footprint-measuring system can differentiate among a normal foot, a flexible flatfoot, and a rigid flatfoot. Classification of metatarsus adductus was questioned, and polydacytyly of the foot was classified in detail. The treatment of leg length discrepancy and angular deformities by osteotomy, hemiepiphysiodesis, and external fixation techniques was described. Several treatments were reported for congenital pseudarthrosis of the tibia. In all, the reports of the past year offer hope for improving the results of treatment by better understanding, innovative surgical techniques, and better methods to determine timing of surgery and predicting results.

The Use of Multiple Pin and Methylmethacrylate External Skeletal Fixation for the Treatment of Orthopaedic Injuries in the Dog and Cat

SummaryMultiple pin and methylmethacry-late external fixation devices were applied in 74 animals to successfully treat several different types of orthopaedic injuries. The major advantages associated with use of the technique included increased versatility in the location and angle of fixation pin place-ment and greater ease in placement of the connecting bar when compared with conventional clamp and connecting bar systems, particularly with transarticular placement of a device. The major disadvantages associated with the technique included, increased difficulty compared to conventional K-E systems regarding postoperative adjustment of the device and difficulty in removing individual pins that were loose or infected. Generally, removal of the device was not a problem, provided sufficient space was left between the connecting bar and the skin surface.Complications associated with the technique were similar to studies which have evaluated other types of external fixation and include fixation pin loosening, pin tract drainage or infection, fixation failure, osteomyelitis, angular limb deformity, mal-union, delayed union and nonunion.The multiple pin and methylmethacrylate external fixator provides a useful and effective method of repair for a wide variety of orthopaedic injuries. The use of methylmethacrylate as a connecting bar is a helpful adjunct to standard external fixation systems.The use of multiple pin and methylmethacrylate external fixation (MPMF) increases the versatility of the external fixation technique in small animal orthopaedic injuries. Disadvantages include difficulty in removing or replacing individual fixation pins.

Diagnosing Instability

The various definitions of instability are reviewed and preference is given to the definition of instability as a loss of stiffness. This definition fits with current laboratory observations. Roentgenographic changes, particularly those associated with degeneration, have no relationship to instability. Multiple roentgenographic images can be of use, but accuracy is limited, and often valuable information at midmotion range or in other planes is missing. Stereoroentgenography appears to offer some promise, but implanted metallic markers are necessary to attain adequate accuracy. Ionizing radiation dose levels are of concern in these techniques. External fixation techniques appear to be of use in some patients. Kinematic linkages and frames containing infrared light emitting diodes are extremely promising, because they give kinematic information in detail.

Treatment of unstable tibial diaphyseal fractures with minimal internal and external fixation.

We prospectively studied 20 patients whose selected unstable tibial diaphyseal fractures were treated with the combined techniques of minimal internal fixation and external fixation. Five fractures were closed and 15 were open (six Grades I and II, nine Grade III). Seventeen were due to high-energy injuries. The minimum followup was 2 years. All fractures healed, one with malalignment. Time to union averaged 12 weeks in closed fractures and 19 weeks in open fractures. All high-energy fractures underwent bone grafting. The external fixation was removed by dynamization. Thirteen complications occurred in nine patients, all with open fractures. Three of 120 pins became infected (2.5%). Early bone grafting and dynamization of the external fixation prevented the malunions and nonunions reported previously with this technique.

External Fixation Shoulder Arthrodesis

Shoulder arthrodesis, while providing a useful and predictable solution to many problems associated with glenohumeral degeneration, has been less than desirable for many patients due to the frequent need for postoperative spica cast or airplane splint immobilization. A new technique of external fixation of shoulder fusions has been developed that provides many advantages, including strong, reliable fixation, obviating the need for bulky casts or splints, and immediate postoperative use of the involved arm. This technique of shoulder arthrodesis using the Hoffman external fixation device has been used on four patients, with a follow-up period of 30-36 months. The series includes patients with infected arthroplasty, osteoarthritis, tumor, and previous failed arthrodesis. Bony union was obtained in six to 10 weeks, and the external fixation frame was left in place seven to 14 weeks. In each case, the external fixation frame enabled the patient to use the involved arm immediately after operation.

Placement of Multiple Full Pins for External Fixation Technique and Results in Four Dogs

A technique using a third bar and guide clamp was developed to permit reduction and stabilization of distal limb fractures with full pins and two connecting bars, one on each side of the bone. The system uses only single Kirschner clamps. Four distal limb fractures were stabilized using this technique. Closed reduction was used in three dogs to avoid devitalization of fragments and avoid contamination of a closed fracture. The fracture site stability achieved with this configuration allowed early return to weight bearing and rapid bone healing.

Arthrodesis of the Knee with Intramedullary Fixation

The application of intramedullary fixation for arthrodesis of the knee has been limited by the technical problems of rod failure and fracture of the femur at the rod insertion site. Improved implant design and rod insertion technique were utilized in seven patients with uniformly successful results. Intramedullary fixation provides prolonged stable fixation and is an alternative to the external fixation techniques currently used to achieve knee arthrodesis.

A technique of external fixation for open dislocations of the wrist joint

A simple technique is presented for external fixation of fracture-dislocations around the wrist joint using materials that are readily available in the operating theatre—methylmethacrylate cement, Kirschner wires and bone plates.

External Skeletal Fixation of Comminuted Maxillary Fractures in Dogs

An external skeletal fixation technique that was effectively applied on comminuted maxillary fractures is described. With this method, pairs of Kirschner wires and/or Steinman pins were seated into the fracture fragments and the exposed cut ends of the pins were embedded into an acrylic bridge. Excellent stabilization of the fractures was effected and normal oral alimentation was resumed immediately. Healing of the fractures usually occurred within two or three months and the pins were then removed. Three representative cases are presented.

External Fixation in Maxillofacial Surgery

The role of external fixation in the treatment of facial fractures is well defined. If standard open reduction and internal fixation techniques do not yield a satisfactory result, external fixation techniques may be required. Open reduction has the advantage of effecting precise approximation of fragments. However, this type of fixation may be inadequate, either because no stable point is available or because the angle of traction involved in fixation may result in displacement of the reduced fracture and subsequent malunion. When the facial skeleton is fractured, it tends to collapse inward, and if injury is severe, an external traction point anterior, lateral, or superior to the facial skeleton may be required to obtain a satisfactory result. There are occasions when intermaxillary fixation may be inadvisable, and in these instances external fixation techniques may be an appropriate means of immobilization. Finally external fixation techniques may be required in instances in which massive tissue loss precludes the use of standard open reduction and internal fixation techniques. It must be reemphasized that the methods of external fixation described here are not meant to supplant the standard techniques of open reduction and interosseous wiring, but when judicially employed complement them in achieving the desired result of precise reduction and firm fixation of the fractured facial skeleton.