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Biomedical subjects

S T Hansen

Publications and source records attributed to S T Hansen.

89 records · Page 5Linked to original sources

Closed intramedullary nailing of femoral fractures. A report of five hundred and twenty cases.

Intramedullary nailing was performed on 520 femoral fractures in 500 patients. The series included eighty-six open fractures and 261 comminuted fractures. Closed intramedullary nailing was used in 497 femora and open intramedullary nailing with cerclage wiring, in twenty-three. The union rate was 99.1 per cent. The range of motion of the knee at follow-up averaged 130 degrees. Complications included four infections (0.9 per cent). Shortening of more than two centimeters occurred in ten patients (2.0 per cent) and malrotation of more than 20 degrees was observed in twelve patients (2.3 per cent). After prompt emergency measures had been taken, routine treatment included strong preoperative traction followed by accurate positioning of the patient on the operating table; selection of the correct insertion point for a properly sized, prebent, flexible, bullet-tipped nail; and accurate reduction of the fracture. Careful rehabilitation of the patient also contributed to the excellence of the results.

Adolescent↗

Temporary intraluminal shunts: resolution of a management dilemma in complex vascular injuries.

Complex vascular injuries of the extremities in which acute arterial insufficiency is combined with severe or prolonged shock, extended periods of ischemia, or associated fractures or soft-tissue injuries have unacceptably high limb loss rates, frequently because the allowable warm ischemia time for skeletal muscle is exceeded before adequate revascularization. In a 1-year period, ten patients with complex vascular injuries identified at our metropolitan trauma center underwent routine introduction of temporary plastic intravascular shunts at the site of vessel disruption, thus permitting immediate limb revascularization. This rapid reperfusion permitted appropriate attention to be directed toward skeletal fixation, soft-tissue debridement, and other procedures without the urgency usually associated with the presence of acute limb ischemia. Following various local and distant orthopedic or general surgical procedures, arterial and venous continuity were uneventfully re-established. This experience suggests that the routine use of plastic intraluminal shunts in complex vascular injuries of the extremities has the distinct potential of reducing the excess morbidity from prolonged acute arterial insufficiency noted in such injuries.

Adolescent↗

Nonunion of the tibia treated with Küntscher intramedullary nailing.

Nonunion of the tibia was treated by Küntscher intramedullary nailing un 48 patients. Thirty patients were treated with a completely closed intramedullary nailing and 18 required an open tibial osteotomy to realign the fracture. Bone grafting was not performed. The average time elapsed from injury to surgery was 15 months and the average healing time, as determined roentgenographically, was nine months following surgery. Three postoperative infections cleared with debridement and antibiotic therapy and subsequently united. There were two failures with persistent nonunion. Closed intramedullary nailing is an effective method of managing nonunion of the tibia in properly selected cases.

Adolescent↗

Comminuted fractures of the femoral shaft treated by intramedullary nailing.

We evaluated 245 cases of comminuted femoral fractures treated by intramedullary nailing and graded them by fracture pattern and degree of stability as segmental fractures, and grade I, grade II, grade III, and grade IV comminuted fractures. The infection rate was 0.4 per cent, and the nonunion rate was 0.8 per cent. Shortening of more than 2 cm. was seen in seven cases (3 per cent), and malrotation of more than 20 degrees was noted in four cases (1.7 per cent). These more common problems of shortening and rotation were almost eliminated by the increased use of cerclage wire and postoperative traction and spica casts. Knee range of motion averaged 128 degrees. These fractures provide interesting and difficult challenges. Intramedullary nailing of the segmental fractures is technically demanding but offers excellent results in these otherwise difficult fractures. Patients with grade I and grade II comminuted fractures do well with intramedullary nailing and the bones remain stable. Grade III and grade IV comminuted fractures are unstable and pose the risk of shortening and rotation. Therefore, to gain anatomic restoration in a young person we believe that it is reasonable to perform an open reduction and cerclage wiring of these fractures. The postoperative treatment of the comminuted femoral fracture is determined by both fracture stability and patient reliability, and frequent roentgenograms are indicated. Most importantly, the surgeon should be prepared to apply whatever form of treatment he believes to be necessary to gain optimal results in each individual.

Adolescent↗

Open fractures of the tibia: a review of one hundred and two cases.

One hundred and two consecutive open fractures of the tibial shaft were treated from 1970 to 1976. Four required primary amputation. The remainder received standardized wound care, consisting of surgical débridement and delayed primary wound closure. Soft-tissue injuries were classified according to severity, because the initial injury was the most important prognostic factor. All patients received a seventy-two-hour course of parenteral antibiotics. Fifty-six fractures were managed with cast immobilization, thirty-five with rigid internal fixation, and seven with rigid external pin fixation. The over-all rates of infection (15 per cent) and delayed union (13 per cent) are not directly comparable to other series because one must consider the severity of each injury when analyzing results. Management of the fracture itself should be individualized. The risk of primary wound closure does not appear to be warranted.

Adolescent↗

Segmental fractures of the femur treated by closed intramedullary nailing.

Twenty acute segmental fractures of the femoral shaft were treated with closed intramedullary nailing. The severity of the soft-tissue damage and associated injuries necessitated careful preoperative care. The surgical technique and means of reduction are outlined. Follow-up of at least one year on all patients showed a 100 per cent rate of union with no infections. Major complications included splitting of the greater trochanter during nailing (one case) and an 11-degree valgus deformity (one case). Maximum shortening was 1.5 centimeters. Knee flexion averaged 135 degrees in these acute fractures. The results in this series indicate that closed intramedullary nailing is an excellent method of treatment for this difficult fracture.

Adolescent↗

Closed intramedullary shortening of the femur.

Closed intramedullary shortening of the femur in the adult provides a method for leg length equalization that poses minimal operative risks, maximizes healing, and produces an excellent functional and cosmetic result. The etiology of anisomelia and any associated abnormalities must be carefully analyzed preoperatively. A series of 40 closed intramedullary shortenings of the femur were performed; shortening averaged 3.3 cm (range 2.0 to 5.0 cm). Three patients had significant complications: delayed union in one patient required renailing; two cases of symptomatic external rotation deformity required correction. The technique for the procedure is demanding in terms of experience and equipment. Otherwise, intramedullary femoral shortening is an excellent method for managing adult anisomelia.

Adolescent↗

Biomechanical analysis of the first metatarsocuneiform arthrodesis.

This investigation was designed to help define the unique loading characteristics of the first metatarsocuneiform arthrodesis procedure. Part I of this investigation employed nine fresh frozen, matched-pair cadaveric specimens. One specimen in each pair had the subchondral plate removed from the opposing joint surfaces, while the remaining specimen had only the articular cartilage removed. All specimens were stabilized in an identical manner utilizing two 3.5-mm cortical screws. Part II of the investigation also utilized nine fresh frozen, matched-pair cadaveric specimens. Only the articular cartilage was removed prior to placement of fixation. All specimens were stabilized with two crossing 3.5-mm cortical screws. Placement of a third screw was randomized between specimens of a matched pair. Specimens were loaded to failure in cantilever bending utilizing a materials tester. There was a statistically significant (p = .04) greater load to failure and bending moment in specimens with an intact subchondral plate. Values for construct stiffness were not found to be significantly different (p = .95) between specimens with and without a subchondral plate. Although the addition of a third screw increased the load to failure and bending moments, differences were not found to be statistically different (p = .11-.21) from two screws. Preserving the subchondral plate will enhance the stability of the first metatarsocuneiform arthrodesis. Two or three screws can be employed to shield the fusion site from loading; however, three screws were shown to be more effective than two.

Adult↗

Effect of calcaneal lengthening on relationships among the hindfoot, midfoot, and forefoot.

To better understand the bony component of pes planus and the means by which the Evans calcaneal lengthening corrects them, we studied the standing radiographs of seven adult patients who had undergone calcaneal lengthening to treat symptomatic pes planus. Weightbearing AP and lateral views done preoperatively and postoperatively were used for the study. For each set of films, the following parameters were measured: on the lateral view; overall length of the calcaneus, lateral talometatarsal angle, lateral talocalcaneal angle, and the calcaneal pitch angle; and on the dorsoplantar view, the talometatarsal and talocalcaneal angle. In addition, the relative coverage of the talus by the navicular was described by an angular measurement based on the relationship of the center of the talus to the center of the navicular. The average improvements in lateral talocalcaneal angle (a reflection of hindfoot valgus) was 6.4 degrees when the long axis of the calcaneus was used and 6.8 degrees when the inferior surface of the calcaneous was used for the measurement. The lateral talometatarsal angle improved an average 11.3 degrees (from an average of 19.7 degrees to 8.4 degrees). The dorsoplantar talometatarsal angle (a measure of forefoot adduction/abduction) improved 15.8 degrees (preoperative average 26.8 degrees, postoperative average 11 degrees). The calcaneal pitch angle improved an average 10.8 degrees (preoperative average 3.2 degrees, postoperative average 14 degrees). The relationship between the talus and navicular was defined by an angular measurement based on the center of each articular surface before and after correction using this measurement. An average improvement of 26 degrees occurred in the alignment of these two articular surfaces.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Closed intramedullary nailing of the femur. Küntscher technique with reaming.

Closed intramedullary reaming and nailing with a prebent cloverleaf nail provides a biomechanically ideal method of internal fixation for femoral fractures. With a properly trained surgical team and careful technical control, all the theoretical advantages of this technique can be realized. These include a very high union rate, minimal risk of infection, early mobilization, and shortened hospitalization. Reaming and insertion of the nail is performed through a starting point at the junction of the base of the femoral neck and trochanter. When reaming is done, the nail can be sufficiently large to withstand the forces of early ambulation, thereby allowing an early return to normal function for most patients. In comminuted fractures an intramedullary nail can be used as an internal splint. In conjunction with traction and/or guarded weight-bearing and/or cast-brace, this procedure can assure earlier and more anatomic union and earlier return to function. In 300 fresh femoral fractures treated with closed intramedullary nailing, most patients had early and nearly anatomic union with excellent knee function and maintenance of muscle strength. Significant complications included one non-union, which required renailing, and 19 malunions, most of which were relatively minor. Because the procedure is technically demanding and requires extensive special equipment, it is best suited for use in trauma centers.

Adolescent↗