Chemical immobilisation of giraffe to facilitate short procedures

OBJECTIVE: To evaluate the effects of dynamization of a sliding hip screw plate on the fixation stability for several types of subtrochanteric fractures. Clinical results of treating reverse oblique fractures occasionally show medialization of the femoral shaft. DESIGN: Two types of plate dynamization were compared using the same test protocol in identically prepared groups of uniform, artificial femurs. METHODS: Sawbones composite femurs (Pacific Research Labs, Vashon, WA) having five orientations of simulated subtrochanteric fractures were used with the Medoff plate (Medpac, Inc., Valencia, CA) either fully dynamized or with the sliding lag screw locked. These specimens were physiologically loaded and cycled and displacements of the proximal femur determined. RESULTS: Significantly more shaft medialization occurred with reverse oblique fracture patterns when the Medoff plate was fully dynamized. CONCLUSION: Clinical treatment of reverse oblique fractures with the Medoff plate should be performed using the lag screw locked and only the plate dynamized.     

Modified medial displacement and valgus osteotomy for unstable intertrochanteric fractures

We have described previously a modification of the medial displacement and valgus osteotomy of Dimon and Hughston to manage non-unions of intertrochanteric fractures. In this study, we have used the same modification to manage fresh, unstable intertrochanteric fractures. Eighty-seven patients underwent this procedure. Four died within 4 months. The remaining 83 patients were evaluated over a period ranging from 4 to 49 months. There was a low complication rate with this method. They included one perforation of the femoral head, one post operative infection that recurred as a deep infection, one partial superior migration of the implant, one varus fixation with noticeable shortening and two cases where the trochanteric wire had snapped. In the others, the hip movement, abductor function, functional recovery and rate of union (8-12 weeks) were good. The method permits early weight-bearing and avoids some of the problems seen with anatomical fixation of unstable fractures using the sliding screw plate. We feel that medial displacement and valgus osteotomy with an angled blade plate has a definite role in the treatment of unstable intertrochanteric fractures in some situations.     

Eruption times of third molars in young rural Nigerians

The mechanical stability of proximal femoral osteotomies fixed by the tension band wire technique was studied in flexion-compression and torsion tests. The fixation consisted in crossing the section with two Kirschner wires and with a wire cerclage applied to the tension surface. The study was conducted in three steps. First, cyclinders of wood were cut either transversely or at 30 degrees of inclination in relation to the long axis of the specimen, and fixed with two Kirschner wires and a wire cerclage. We concluded that the inclination of the plane of section significantly increased the stability of fixation. No significant difference was observed when oblique sections were made in the reverse orientation. Second, 30 degrees subtrochanteric varus osteotomies were performed in dog femurs, so that the section plane was transverse in one group and oblique in another, after closing the osteotomy. In both groups the fixation was achieved by two Kirschner wires that crossed the osteotomy and a wire cerclage placed on the lateral cortex (tension surface). We concluded that inclination of the osteotomy plane increased the stability of osteosynthesis in bone specimens, as already seen with the wood pieces. Third, the stability of tension band wire fixation was compared with that provided by the AO/ASIF paediatric angled plate. Varus osteotomies (30 degrees) were created at the subtrochanteric level of paired dog femurs. On one side, the femur was fixed with Kirschner wires and a wire cerclage as described previously. For the other femur, the osteotomy was fixed with the angled plate. We found that both types of fixation presented the same stability in flexion-compression tests. However, under torsion the tension band wire fixation was 30%-50% less stable than the plate fixation.     

Treatment of cutout of a lag screw of a dynamic hip screw in an intertrochanteric fracture

Sixteen consecutive patients with cutout of a lag screw of a dynamic hip screw fixation in an intertrochanteric fracture were treated with reinsertion of a lag screw, bone cement supplementation in the neck-trochanter, and subtrochanteric valgus osteotomy. Postoperatively, patients were permitted to ambulate with protected weight-bearing. Fourteen patients were followed-up for at least 1 year (median 2 years; range 1-3 years), and all had a solid union. The union period took a median of 5 months, with a range of 3-7 months. Usually, union of an intertrochanteric fracture was faster than that of subtrochanteric osteotomy (P < 0.01). There were no complications of wound infection, loss of reduction, cutout of a lag screw, or osteonecrosis of the femoral head. From clinical and theoretical considerations, we conclude that despite cutout of a lag screw of a dynamic hip screw fixation being difficult to treat, out technique still can provide an excellent outcome. Therefore, we strongly recommend its wide use.     

The reconstruction locked nail for complex fractures of the proximal femur

Thirty-seven patients with 37 proximal femoral fractures were treated with a reconstruction locked femoral nail. There were four ipsilateral intracapsular femoral neck and shaft fractures, two intertrochanteric fractures, 18 intertrochanteric fractures with diaphyseal extension, eight subtrochanteric fractures with involvement of the lesser trochanter, and five subtrochanteric fractures without involvement of the lesser trochanter. The overall union rate was 92%. Twenty-one complications developed in 13 patients (35%) which included three of the four femoral neck and shaft fractures, and six of 18 intertrochanteric fractures with diaphyseal extension. Of the five intertrochanteric fractures with diaphyseal extension in which anatomic reduction was not achieved, four developed a complication. Of the nine proximal screws in nine fractures, which were placed short (below the subchondral bone of the femoral head), six fractures developed a complication. The complications included three nonunions, one delayed union, two leg-length discrepancies of > 2.5 cm, two cases of varus deformity of > 10 degrees, two varus deformities < 10 degrees, four instances of revision surgery including one broken 13-mm nail, four proximal screws that backed out and required removal, two cases of pudendal nerve palsy, and one case of heterotopic ossification. Seven patients developed more than one complication. Eleven of the 13 patients with complications required a second surgery to treat the complication. We conclude that the reconstruction locked femoral nail is not a good choice for ipsilateral intracapsular neck and shaft fractures. Our recommendation is that anatomic reduction should be achieved for all cases using the reconstruction femoral nail, but it is absolutely required when treating the intertrochanteric fracture with diaphyseal extension. Reconstruction femoral nails have a high rate of complication due to the complex nature of the fractures as well as the device.     

Clinical diagnostic valuation cine magnetic resonance coronary angiography

OBJECTIVES: This biomechanical cadaver study was performed to compare the fixation stability of a standard lateral condylar buttress plate with a similar condylar buttress plate with the distal screws locked to the plate. Then the study was repeated with six additional matched femoral pairs to compare the locked plate with a standard 95-degree blade plate. DESIGN: Six matched pairs of mildly osteopenic femurs were selected, and each side was assigned randomly to fixation with either a standard lateral condylar buttress plate or a modified lateral condylar buttress plate with locked distal screws. The experiment was repeated with six additional matched pairs of femurs instrumented with either a modified lateral condylar buttress plate with locked distal screws or a standard 95-degree blade plate. INTERVENTION: The femurs were instrumented, and a gap osteotomy was created at the distal femoral metaphysis. The instrumented femurs were then mechanically tested in axial compression and bending/torsional loading to determine fixation stability; then they were loaded at 1,000 newtons for 10(5) cycles and retested for stability. MAIN OUTCOME MEASUREMENT: The displacement across the osteotomy gap at 100-newton and 1,000-newton axial loads was measured directly for each specimen before and after cycling. In addition, resistance to displacement in bending/torsional loading (newtons/centimeter) was determined from load/displacement curves, before and after cycling. RESULTS: The locked buttress plate provided significantly greater fixation stability than the standard plate both before and after cycling in axial loading. The locked buttress plate also proved significantly more stable in axial loading than the blade plate both before and after cycling. CONCLUSION: A condylar buttress plate with locked screws is a valid concept for improving fixation stability.     

Aerial fallout of DDT in southern California

Ender's method of intramedullary fixation of intertrochanteric and subtrochanteric fractures is described. Ender's nail is a pre-bent flexible steel nail with a diameter of 4.5 millimeters. Three to five of these nails are inserted from a small incision proximal to the medial epicondyle of the femur into the medullary canal. They are passed through the femur across the fracture site and into the head of the femur, where they diverage. They are in the lines of force and therefore are not subjected to bending moments. The fracture fixation allows immediate weight-bearing. This method of fixation was used in a series of 203 patients. Their average age was sixty-eight years; the mortality rate was 10.3 per cent. In 3.9 per cent superficial infections occurred, but in no case was there a deep infection involving the bone. Functional return (walking) was achieved in all of the survivors who were able to walk at the time of injury, and there were no nonunions.     

Proximal femur fractures after free vascularized fibular grafting to the hip

The management of symptomatic femoral head osteonecrosis in young, active patients is troublesome and controversial. At the authors' institution, 707 consecutive free vascularized fibular grafts were performed for femoral head osteonecrosis between October 1979 and October 1995. Patients who underwent this procedure were at increased risk for proximal femur fractures because of the 16 to 21 mm core drilled through the lateral femoral cortex for removal of the avascular bone and placement of the fibular graft. An ongoing prospective database of patients who underwent this procedure was accessed to determine the incidence of and factors associated with postoperative subtrochanteric femur fractures. Eighteen subtrochanteric fractures occurred for an overall incidence of 2.5%. All fractures occurred through the core decompression site in the lateral femoral cortex. The treatment was nonoperative in seven patients and operative in 11. Fourteen of 18 fractures (77%) healed with an average of 4.1 months until radiographically documented union. Four fractures had nonunions develop, three of which later healed with bone grafting and internal fixation, whereas the fourth eventually required conversion to total hip arthroplasty. Twelve fractures in 251 patients occurred when the weightbearing regimen was touchdown weightbearing for the first 6 weeks and five fractures in 456 patients occurred when the weightbearing regimen was changed to nonweightbearing. The results indicate that nonweightbearing in the immediate postoperative period is associated with the lowest fracture rate.     

Predicting the mechanical outcome of femoral neck fractures fixed with cancellous screws: an in vivo study

OBJECTIVE: The goal of this project was to determine, by using a retrospective cohort analysis, the relative importance of fracture geometry, bone density, and quality of fracture reduction in predicting redisplacement of femoral neck fractures fixed with multiple cancellous screws in a patient population. DESIGN: A retrospective analysis of quantitative geometric and bone density data from forty-seven patients with femoral neck fractures fixed with cancellous screws was performed. SETTING: Radiographs retrieved after analysis of a statewide hospital database were digitized and analyzed quantitatively. INTERVENTION: Quantitative data from radiographs included estimates of femoral neck bone density, fracture surface orientation and location, degree of comminution, prefixation displacement, initial reduction position of the fractured component, and final displacement of the fracture after fixation. MAIN OUTCOME MEASUREMENTS: Angular rotation and inferior displacement of the fracture component after fixation. RESULTS: Femoral neck bone density can be correlated to femoral cortical thickness and can be used as a measure of bone density from plain x-rays. Significant relative risk of redisplacement of a femoral neck fracture is correlated with initial inferior offset of the fracture component and varus angulation. Relative risks of other variables, including valgus reduction, Garden Stage 3 and 4 position of the femoral head, low bone density, presence of inferior comminution, a more vertical fracture surface angle, and fracture position, were not significant. CONCLUSIONS: When compared with other geometric and mechanical variables, nonanatomic reduction of a femoral neck fracture, with either inferior offset or varus angulation, is the strongest predictor of postfixation redisplacement of the fracture.     

Load transmission through the callus site with external fixation systems: theoretical and experimental analysis

The fracture callus contribution to the total rigidity of external fixator-fractured bone element was analysed. This study was achieved from both theoretical and experimental perspectives. The theoretical study was done using the finite element method with a three-dimensional model. In this model, both the callus and the development of its elastic characteristics were considered. A series of 38 New Zealand-California white rabbits with tibial fractures treated with some external fixation system was used in this study. Such devices could reproduce either rigid or elastic features. The frame dynamization can be obtained at different fracture healing stages. Animals were classified into four series: (1) rigid fixators, (2) dynamized fixators two weeks after surgery, (3) three weeks after surgery and (4) four weeks after surgery. Tension tests were performed to evaluate callus strength. Theoretical results showed significant levels of callus load transmission (85.5%) when the callus elastic modulus is 1/100 of the elastic modulus of intact bone in an external fixator with rigid features. Experimental analysis of the callus obtained with different external fixator systems did not show differences among them. This fact implies that the immature callus theoretically modelled (E = 100 N mm-2) appears early in the rabbit fracture model (before two weeks, when first dynamization was made), for this reason no differences were found between the two types of treatment (rigid and dynamized systems). This fact questions the reliability of the dynamization process in external fixation of fractures and it implies accurate investigations in the clinical field.     

Mechanical failure of the intramedullary hip screw in a subtrochanteric femoral fracture

The Gamma nail, an implant specifically designed for intertrochanteric and subtrochanteric femoral fractures, has been criticized for its high risk of secondary shaft fractures. A modified design, the intramedullary hip screw has recently been introduced to correct this complication. We present a case of mechanical failure of this new implant that occurred in a pathological subtrochanteric fracture. The centering sleeve of the implant became loose and migrated while the head screw penetrated the acetabulum. Refixation was successful.     

Supplementation of coconut oil from different sources to the diet induces cellular damage and rapid changes in fatty acid composition of chick liver and hepatic mitochondria

PURPOSE OF THE STUDY: Impaction in pertrochanteric fracture sites is a well known phenomenon; the screw-plate system is designed to stabilise the fracture. Although easier to use, the risk with the nail-plate system is postoperative penetration of the nail into the joint. The present study was conducted to determine the exact conditions of the impaction, and to identify possible ways to improve the nail-plate system. MATERIAL-METHOD: The study included 129 cases of pertrochanteric fracture, excluding sub-trochanteric fractures. All fractures were fixed with a 130 degrees angulated nail-plate. In all cases, consolidation was uneventful after 8 to a 12 weeks. The anatomical type of fracture, i.e. stable or unstable, was determined according to the size of the intermediary fragment, including the trochanter minor. The displacement was measured as the difference between the length of the nail and the length of the femoral head and neck measured along the axis of the femoral neck. The parameters examined were: fracture stability degree, bony mineralisation (Singh Index), nail length, femoral neck, length nail position in the femoral head, and above all, fracture reduction. All these parameters were computerised and compared using Stat View statistics software. RESULTS: Impaction was observed in 43 per cent of cases. Among these, 25 per cent were rated as slight (1 to 5 mm), 18 per cent as moderate (over 5 mm) and 9 per cent as marked (10 to 25 mm). Impaction was associated with demineralisation of the bone tissue (p = 0.001). The anatomical classification of the fracture was not a determining factor (p = 0.19), as marked displacements were also recorded in stable fractures. A posterior and inferior position of the intramedullary nail in the femoral head is one of displacement determining factors (p = 0.004, two-sided 1 test). Valgus over-correction is the most important factor, especially when it is associated with bony demineralisation (p = 0.02) and an inadequately centred intramedullary pin (p = 0.02). Shorter the femoral neck, and shorter the nail, greater was the frequency of nail articular penetration. DISCUSSION: The risk of articular penetration therefore reaches 15 per cent in petrochanteric fractures repaired with a nail plate, set at an angle of 130 degrees. A short neck, a cervicodiaphyseal angle superior to 140 degrees, and demineralisation are the three determining parameters. Stable or unstable fracture has in fact little effect on displacement incidence, and therefore does not, on its own, warrant the use of a prosthesis in comminuted fractures. The authors compared their results to literature on progressive sliding system: the incidence of complications associated with this type of fracture treatment is identical, but the determining parameters are different. CONCLUSION: The study shows that the nail-plate is efficient and provides simple and solid fracture fixation. However, this osteosynthesis material needs to be modified in order to improve its fixation in the femoral head.     

Neuronal death induced by SIN-1 in the presence of superoxide dismutase: protection by cyclic GMP

OBJECTIVES: To test whether femoral ostectomy level, subtrochanteric bone mass removal, and stemsize selection significantly affect stem positioning in canine total hip replacement, and to determine ability of the femoral stem component to restore geometry of the normal femoral head and neck. SAMPLE POPULATION: Femurs from 8 adult mixed-breed canine cadavers. PROCEDURE: Femurs were systematically prepared, using 8 combinations of 3 surgical preparation techniques that included level of ostectomy (cervical isthmus vs lesser trochanter), subtrochanteric bone block removal, and femoral stem size (recommended, undersized). Computer-aided analysis of specimen photographs was used to evaluate femoral head offset and position and variability of femoral stem positioning for each of the preparation combinations. RESULTS: Original femoral head offset and position were reconstructed to within a mean of 0.052 and 0.031 cm, respectively, using an undersized femoral stem after ostectomy at the level of the lesser trochanter. Implantation of an undersized femoral stem after subtrochanteric bone block removal improved ability to centralize the distal tip of the implant and reduce the angle between the femoral diaphyseal and implant axes. Ostectomy at the level of the cervical isthmus tended to force femoral implants into a varus position, and ostectomy at the level of the lesser trochanter tended to force implants into a valgus position. CONCLUSIONS: Geometry of normal canine femurs was most closely reconstructed by implantation of an undersized femoral component after ostectomy at the level of the lesser trochanter. Implantation of an undersized femoral component after subtrochanteric bone block removal resulted in the best alignment and centralization of the stem.     

Results of total hip arthroplasty for Crowe Type III developmental hip dysplasia

From 1969 through 1980, 90 hips in 82 patients had cemented total hip arthroplasty for Type III developmental hip dysplasia. Seventy hips were reviewed at an average of 16.6 years (range, 5-23 years) after operation. Aseptic loosening developed in 53% of acetabular cups and 40% of femoral stems. Despite attempts to place acetabular components in the anatomic center, 18 cups (25.7%) were placed outside that area. Using a measurement method to determine the true acetabular region and approximate femoral head center, final acetabular loosening strongly correlated with initial cup placement. Loosening occurred in 15 of 18 cups (83.3%) initially positioned outside of the true acetabular region compared with loosening in 22 of 52 cups (42.3%) initially positioned within the true acetabular region. Acetabular loosening also correlated with initial lateral displacement or initial superior displacement of the hip center from the approximate femoral head center. Initial cup placement medial to the approximate femoral head center was predictive of successful long term acetabular component fixation. The method of acetabular reconstruction did not affect eventual cup loosening. Placement of the hip arthroplasty center of rotation in or near the true acetabular region is recommended.     

Total avascular necrosis of the capital femoral epiphysis in congenital dislocated hips

Ninety-four hips involved with total avascular necrosis in the treatment of congenital dislocation of the hips were reviewed in a search for etiological factors and effective salvage procedures. Pre-reduction traction and adductor tenotomy did not prevent avascular necrosis. Abduction of the hip in the "frog" position was the incriminating common denominator. This position may cause (1) interference of the blood supply to the femoral head by compression of the medial branch of the deep profundus artery; and (2) pressure on the intraepiphyseal grooves by the glenoid labrum. The containment of the femoral head by acetabuloplasty (preferably) below age 8, followed at a later date (over age 10) by transfer distally of the greater trochanter, with the abductor muscles, offers a satisfactory salvage procedure.     

Norian SRS cement augmentation in hip fracture treatment. Laboratory and initial clinical results

Bone quality, initial fracture displacement, severity of fracture comminution, accuracy of fracture reduction, and the placement of the internal fixation device are important factors that affect fixation stability. New high strength cements that are susceptible to remodeling and replacement for fracture fixation may lead to improved clinical outcome in the treatment of hip fractures. Norian SRS is an injectable, fast setting cement that cures in vivo to form an osteoconductive carbonated apatite of high compressive strength (55 MPa) with chemical and physical characteristics similar to the mineral phase of bone. It can be used as a space filling internal fixation device to facilitate the geometric reconstruction, load transfer, and healing of bone with defects and/or fractures in regions of cancellous bone. Furthermore, this cement can improve the mechanical holding strength of conventional fixation devices. Use of this material potentially could improve fracture stability, retain anatomy during fracture healing and improve hip function, thus achieving better clinical outcomes. In vivo animal studies have shown the material's biocompatibility, and cadaveric studies have shown the biomechanical advantage of its use in hip fractures. Initial clinical experience (in 52 femoral neck fractures and 39 intertrochanteric fractures) showed the potential clinical use of this innovative cement in the treatment of hip fractures.     

Hip fusion in young adults. Using a medial displacement osteotomy and cobra plate

Eight consecutive patients, mean age 17.25 years, underwent a medial displacement osteotomy and hip arthrodesis with a nine-hole Cobra plate. A transverse innominate osteotomy facilitated medial displacement of the femoral head and acetabulum. Alignment of the lower limb at 25 degrees flexion, neutral abduction, and neutral rotation was assisted by a long-limbed protractor and Steinmann pins placed in both anterior superior iliac spines. The greater trochanter was reattached to the Cobra plate so that hip abductor function could be restored should the fusion ever be converted to an arthroplasty. No postoperative immobilization was required. All patients had radiographic evidence of union by 12 months. One patient had a postoperative brachial plexus neuropraxia that resolved at three months. One patient required an ipsilateral femoral lengthening for limb-length inequality secondary to collapse of his femoral head before hip fusion. At a mean follow-up interval of 2.8 years (range, one to 4.5 years), all patients had significant improvements in pain (p < 0.05), function (p < 0.01), and gait (p < 0.01). The average preoperative Harris Hip Score of 45 points +/- 8 points (mean +/- SEM) improved to 84 points +/- 2 points (p < 0.01).     

Failure of ketoprofen and interferon combination therapy to improve interferon-resistant chronic hepatitis C

Previous studies have documented the effectiveness of magnetic resonance imaging for evaluating and following up the development of avascular necrosis of the femoral head. One of the limitations of this technique, however, is the distortion that is encountered with ferromagnetic screws. A traumatic fracture to the femoral head is a risk factor for avascular necrosis. The addition of internal fixation, which is often required in Pipkin-type fractures of the femoral head, creates significant image distortion on magnetic resonance scans used for postoperative follow-up. The artifact and field distortion present in magnetic resonance imaging when ferromagnetic screw fixation is used has been avoided at our institution by the use of titanium hardware. The authors, therefore, recommend the use of titanium screws in the fixation of Pipkin-type fractures in the hip joint.     

Retrograde intramedullary nailing of supracondylar femoral fractures

As an alternative to standard AO/Association for the Study of Internal Fixation plate and screw techniques, retrograde intramedullary locked nailing of supracondylar and intracondylar (AO/Association for the Study of Internal Fixation Type 33) fractures is reviewed. This includes a historic review, the technique for knee arthrotomy, fracture reduction and nail insertion, and the reported clinical and biomechanical results. The retrograde intramedullary locked nail is a viable alternative for the treatment of AO/Association for the Study of Internal Fixation Type 33-A and some C supracondylar femoral fractures and should be part of the internal fixation armamentarium, however, it does not replace the standard biologic plate and screw techniques for most fractures.     

Indications for use of the long Gamma nail

A retrospective analysis of 42 patients treated by intramedullary nailing with the Gamma nail with a mean followup of 22.4 months is reported. The indications for the use of this nail were subtrochanteric fractures in 31 cases, diaphyseal femoral fractures in 10 cases, and segmental fracture in one case. Seven cases of the diaphyseal fractures were renailings for a previously placed nail. There was one pathologic fracture in the subtrochanteric group and three in the diaphyseal group. The indications of this new technique and its complications are analyzed.