Operative management of diaphyseal fractures of the humerus. Plate versus nail

Although nonoperative treatment is indicated and successful for the majority of diaphyseal humeral fractures, operative intervention is indicated in several situations. Either intramedullary nail or plate fixation commonly is used for the operative management of this problem. Familiarity with the surgical techniques and application of both types (and subtypes) of implants is necessary to allow optimal treatment for the widest range of fracture patterns. In most indications for operative management, internal fixation with plates is preferred. Stable fixation, sparing adjacent joints from iatrogenic injuries, and direct visualization and protection of the radial nerve are of critical importance in maximizing postoperative function and in most cases outweight the potential advantages of a loadsharing implant inserted through a more limited incision.     

Selfish genes, pleiotropy and the origin of recombination

If multiple linked polymorphisms are under natural selection, then conflicts arise and the efficiency of natural selection is hindered relative to the case of no linkage. This simple interaction between linkage and natural selection creates an opportunity for mutations that raise the level of recombination to increase in frequency and have an enhanced chance of fixation. This important finding by S. Otto and N. Barton means that mutations that raise the recombination rate, but are otherwise neutral, will be selectively favored under fairly general circumstances of multilocus selection and linkage. The effect described by Otto and Barton, which was limited to neutral modifiers, can also be extended to include all modifiers of recombination, both beneficial and deleterious. Computer simulations show that beneficial mutations that also increase recombination have an increased chance of fixation. Similarly, deleterious mutations that also decrease recombination have an increased chance of fixation. The results suggest that a simple model of recombination modifiers, including both neutral and pleiotropic modifiers, is a necessary explanation for the evolutionary origin of recombination.     

Small wire external fixation of high energy tibial plateau fractures

Open plate osteosynthesis for high energy tibial plateau fractures with dissociation between the metaphysis and diaphysis has been plagued with frequent soft tissue complications. The Harbor-University of California at Los Angeles Medical Center's experience with small wire external fixation supplemented by limited internal fixation is examined. This alternative method of adequate stable fixation offers the advantage of minimal soft tissue compromise. Twenty-four patients with Schatzker Type VI tibial fractures were treated with small wire external fixation. Supplementary limited internal fixation was used with percutaneous screws in 10 patients and with open reduction in one patient. Sixteen patients had isolated fractures, and eight others suffered multiple injuries. Minimum followup was 12 months. All fractures healed. Complications included one septic knee, two infections at screw sites, and one 10 degrees knee flexion contracture. One knee had Grade 3 radiographic arthrosis, five had Grade 2, 10 had Grade 1, and eight showed no arthrosis. The outcomes (Knee Society clinical rating system) of this study compare favorably with outcomes described in reports published previously for this type of fracture, despite inclusion of eight multiply injured patients. This technique preserves the goals of early range of motion and stable fixation for these devastating injuries, while decreasing the observed major wound complications and nonunion rates. However, longer followup may reveal higher arthrosis rates, specifically in those fractures that were not anatomically reduced.     

Treatment of tibial plateau fractures by limited internal fixation

Seventy-five adults who sustained 76 tibial plateau fractures were treated according to a prospective protocol using instability in extension as the principal indication for operative fixation. Patients showing instability underwent closed manipulative reduction under fluoroscopic guidance. If significant joint depression persisted after reduction, elevation of the fracture was performed either from below using bone punches through a cortical window or via limited arthrotomy. Iliac crest bone graft was used to buttress depressed fractures. Fixation was then secured using 7-mm cannulated screws with washers or buttress plates and screws. Postoperatively, 58 of 76 knees were managed in a hinged knee brace, allowing the patient early range of motion and protected weightbearing for 8 weeks. Patients who were found to have a stable knee were treated with Bledsoe braces according to the postoperative protocol. In the 75 patients, 18 of the 76 knees were unsuitable for percutaneous screw fixation because of fracture complexity requiring plates, severe open injuries, or inadequate reductions with limited fixation had been done. A minimum followup of 12 months was obtained in 55 patients (range, 12-59 months). All fractures had healed at the time of followup. Eighty-seven percent of the patients at followup had a successful outcome using Rasmussen's criteria. Fourteen of these patients had arthroscopic assisted reduction or evaluation. All seven patients who had poor outcomes had AO Type C3 fracture patterns. Severely depressed or comminuted fractures or fractures with significant metaphyseal diaphyseal extension may not be suitable for this technique and require the addition of an external fixation device or buttress plate to maintain the reduction and allow for early range of motion.     

Operative treatment of fractures of the tibial plafond. A randomized, prospective study

We performed a randomized, prospective study to compare the results of two methods for the operative fixation of fractures of the tibial plafond. Surgeons were assigned to a group on the basis of the operation that they preferred (randomized-surgeon design). In the first group, which consisted of eighteen patients, open reduction and internal fixation of both the tibia and the fibula was performed through two separate incisions. An additional patient, who had an intact fibula, had fixation of the tibia only through an anteromedial incision. The second group consisted of twenty patients who were managed with external fixation with or without limited internal fixation (a fibular plate or tibial interfragmentary screws). Ten (26 per cent) of the thirty-nine fractures were open, and seventeen (44 per cent) were type III according to the classification of Rüedi and Allg?wer. There were fifteen operative complications in seven patients who had been managed with open reduction and internal fixation and four complications in four patients who had been managed with external fixation. All but four of the complications were infection or dehiscence of the wound that had developed within four months after the initial operation. The complications after open reduction and internal fixation tended to be more severe, and amputation was eventually done in three patients in this group. At a minimum of two years postoperatively (average, thirty-nine months; range, twenty-five to fifty-one months), the average clinical score was lower for the patients who had had a type-II or III fracture, regardless of the type of treatment. With the numbers available, no significant difference was found between the average clinical scores for the two groups. All of the patients, in both groups, who had had a type-II or III fracture had some degree of osteoarthrosis on plain radiographs at the time of the latest follow-up. With the numbers available, there was no significant difference between the two groups with regard to the osteoarthrotic changes. We concluded that external fixation is a satisfactory method of treatment for fractures of the tibial plafond and is associated with fewer complications than internal fixation.     

Staple leg profile influence on pullout strength: a biomechanical study

Bone staples have widespread applicability in orthopaedic surgery. Their use, however, is limited by inconsistent quality of fixation. Prior studies have shown potential for improvement in the reliability of staple fixation through a change in the design of the staple legs. To identify a superior leg cross section profile, pullout strength of 5 different newly designed staple leg cross sections were evaluated in fresh frozen human cadaveric bones before and after toggle loading. The tests were repeated in a synthetic bone model with variable but consistent densities. The curvilinear square profile had the highest pullout strength in both the cadaveric and synthetic bone, followed in descending order by square, circular, and triangular profiles. Controlling for density, the pullout strength of the curvilinear square profile was 8% higher than the square profile and 34% higher than the circular profile. The triangular profiles had the least resistance to pullout force before and after cyclic loading. The curvilinear square may be the best profile for the cross section of the staple leg for maximum pullout strength and may expand the clinical use of staples in bone fixation.     

The management of war wounds involving bone

Over 200 high-velocity missile injuries treated in a low-technology environment were audited under the aegis of the International Committee of the Red Cross Hospitals in Afghanistan and Northern Kenya. Femoral fractures were treated either by traction or external fixation using a uniaxial frame. The results showed that patients treated by external fixation remained in hospital longer than those treated on traction. The positional outcome was identical in both groups. In tibial fractures the external fixator was only of extra benefit in those of the lower third when compared with simple plaster slabs unless more complex procedures such as flaps or vascular repair were to be performed. In complex humeral fractures, external fixation resulted in long stays in hospital and a large number of interventions when compared with simple treatment in a sling. We conclude therefore that in an environment where facilities are limited and surgeons have only general experience very careful initial wound excision is the most important factor determining outcome. The application of complex holding techniques was generally inappropriate.     

Lumbar percutaneous endoscopic interbody fusion

Since 1982, percutaneous endoscopic control has been found to be a fundamental help for selective posterior subligamentary decompression in lumbar contained disc herniations. After the first clinical experience in 1986 with percutaneous intervertebral bone grafting, the need for sufficient percutaneous preparation of the adjacent vertebral plates and postoperative immobilization of the operated on segment became evident. So in 1988, the original eccentrically abrasive end plate cutter for application under discoscopy was introduced. For a preoperative trial and postoperative stabilization, the complementary use of the external pedicle fixation device was standardized in 1988. The use of percutaneous autologous bone interposition was found essential for optimal bony interbody consolidation. The indications were limited strictly to monosegmental lumbar dysfunctions without a need for peridural decompression. In a series of 37 patients with standardized procedure and a mean followup of 33 months, bony interbody consolidation was achieved in 30 cases. The technique desists from any need for blood transfusion, and functional rehabilitation is facilitated because of the very limited percutaneous approach.     

Lamina lucida of basement membrane: an artefact

In tissues prepared with chemical fixation followed by conventional dehydration, basement membranes have been observed to be laminated structures composed of a lamina lucida and lamina densa as well as a poorly limited transitional zone referred to as the pars fibroreticularis. Scattered attempts in the application of new techniques of tissue preparation such as cryofixation or freeze substitution for the study of the basement membrane structure have been made in recent years. From these studies, the possibility has arisen in which basement membranes are composed of only the lamina densa without a lamina lucida. In recent studies in this laboratory, the attempt was made to determine whether or not this lamina lucida is an artefact, and if so, which step in the conventional method of tissue preparation is responsible for its formation. Basement membranes from diverse sources in the mouse and rat including the testis, ductus epididymis, eye, thyroid, kidney, and skin, were observed after either cryofixation by slam freezing followed by freeze substitution, or aldehyde fixation followed by freeze substitution. The basement membranes after preservation with either of these two methods were composed of only the lamina densa with no lamina lucida. It indicates that an artefactual formation of the lamina lucida occurs during dehydration in conventional tissue preparation rather than during chemical fixation. In view of the well known superiority of freeze substitution over conventional dehydration, the lamina lucida of the basement membrane is likely to be an artefact. Therefore, it is concluded that the lamina lucida is an artefact formed during conventional tissue preparation, and in its original condition in the living state, the basement membrane is composed of a single layer made up of lamina densa material.     

Anomalous systemic arterial supply to the basal segment of the left lung: demonstration using MR angiography

Open reduction with internal stabilization is considered to be the standard therapy for the treatment of displaced acetabular fractures. The internal fixation is routinely achieved by the use of plates and screws. The use of cerclage wires and cables as a reduction aid and definitive implant for stabilization has only occasionally been reported in the literature. The indication was mostly limited to use in elderly patients with insufficient bone stock. A newly instrument developed on the basis of a standard bone elevator is presented. It allows a safe, semiclosed application of a cerclage wire around the greater ischiatic notch through use of the second window of the ilioinguinal approach. A wide dissection at the "outside" of the pelvis is not necessary.     

Failure mechanisms of anatomic porous replacement I cementless total hip replacement

The APR-I Hip System was designed for metaphyseal bone attachment by proximal patch porous coating and the acetabular component was a hemisphere fixed with screws. The results of 100 consecutive primary total hip arthroplasties performed with the APR-I were studied in patients still alive after an average of 6.7 years. The selection of hips for implantation of this hip system was limited to those patients in whom a satisfactory intraoperative fit could be obtained. This resulted in a distribution of patients such that 75% were younger than age 65 years and only 15% had osteoporotic bone. The revision rate was 16% with a mechanical failure rate of 11%. Seventy percent of hips had progressive loss of fixation. loss of femoral component fixation was correlated with younger patient age, higher patient activity level, metaphyseal fill of less than 90%, and increased polyethylene wear and osteolysis. Eighty-nine percent of hips maintained femoral neck contact with the porous coated collar. The acetabular component was well fixed in 97% of hips. The failure rate of the APR-I stem is unacceptably high and this stem is no longer used by the authors.     

Ankle arthrodesis in patients with rheumatoid arthritis

The results of 26 ankle arthrodeses performed for rheumatoid arthritis on 21 patients were reviewed. Tibiotalar arthrodesis was performed in 14 ankles, and tibiotalocalcaneal arthrodesis was performed in 12. External fixation was used in 20 ankles, and internal fixation was used in six. Followup was available in 24 of 26 ankles (19 patients), and averaged 5 years (range, 2-8 years). There was no pain experienced in 19 ankles; mild, occasional pain was experienced in four ankles; and moderate, daily pain was experienced in one ankle. Daily activities were limited in five patients and recreational activities were limited in 11. All patients reported some difficulty walking on uneven terrain. Nearly all patients were satisfied; two were satisfied with reservations and two were dissatisfied. Union was achieved in 25 of 26 (96%) ankles. Ankle arthrodesis is an effective operation in patients with rheumatoid arthritis. Unlike previous reports, union and complication rates in this series were comparable with rates for arthrodesis for posttraumatic and degenerative arthritis.     

Operative treatment of displaced proximal humeral fractures: two-year results in 99 cases

The operative treatment of comminuted and displaced fractures of the proximal humerus has been evolving in recent years. Classical open reduction and internal fixation techniques have an increased risk of avascular necrosis. Minimal osteosynthesis procedures often result in a suboptimal fracture reduction and require postoperative immobilization of the arm in some cases. This study reviewed ninety-nine out of 142 patients (70%), an average of 30 months (range 12 to 72 months) after indirect reduction and internal fixation of two-, three- or four-part fractures of the proximal humerus. The surgical procedure includes indirect fracture reduction with no manipulation of the different fracture fragments and subsequent buttress-plate fixation, using a limited deltopectoral approach. Mean age of patients was 63 years (range 17 to 85 years). Twenty percent of patients had associated lesions. Five patients presented with fracture-dislocations. Results were, according to the UCLA- and the Constant-rating system good to excellent in 76 and 69% of cases. Twelve patients had a poor functional outcome. The indirect reduction technique reduces the opening of the fracture site to minimum and thereby limits the risk of iatrogenic damage to local vascularity and the rotator cuff. Complete and partial humeral head necrosis developed in 3% and 1% of cases respectively. Non-union occurred in one case. Plate fixation is an adequate procedure for treating unstable and displaced two- to four-part fractures of the proximal humerus. The incidence of avascular necrosis and non-union are low, when fracture reduction is performed indirectly. Plate fixation enables an early functional treatment, with no need for postoperative immobilization.     

Valgus osteotomy of the humeral neck: a technique for the treatment of humerus varus

Proximal humerus varus is defined by both its radiographic and clinical characteristics. Clinically significant humerus varus has a proximal humeral neck-shaft angle less than 140 degrees and causes limited active abduction or forward flexion as a result of impingement of the greater tuberosity on the acromion. Weakness of the shoulder girdle is often present as well. The condition may be congenital, developmental, idiopathic, or posttraumatic in origin. Previous treatments for humerus varus have included acromionectomy and wedge osteotomy with placement of the extremity in a shoulder spica cast. This article describes a technique for treatment involving valgus osteotomy of the humeral neck and tension-band fixation. Correction of the deformity allows markedly improved function of the extremity with significant increases in active and passive abduction, forward flexion, and internal rotation.     

A trypsin inhibitor trans-4-guanidinomethylcyclohexanecarboxylic acid 4-tert-butylphenyl ester suppresses the onset of DNA synthesis in Escherichia coli cells synchronized by phosphate starvation

The Resonant Frequency (RF) of the tibia is proportional to its stiffness. As a fractured tibia heals, its RF should increase. The RF was serially determined in 74 fractured tibias (205 examinations). These were subdivided by fracture location and fixation. Fast Fourier transform software generates the RF from data obtained with an instrumented impactor and accelerometer. The RF was normalized by expressing it as a ratio of the intact tibia. This ratio is called the tibial stiffness index (TSI). A 20 point tibial fracture score (TFS) quantitated the clinical and radiographic signs of healing. For each group the paired TSI and TFS were compared by regression analysis. Except for those fractures limited to the proximal fourth of the tibia, the TSI was found to correlate significantly (p = 0.0001) with the TFS. Fractures without fixation and those with unlocked, unreamed tibial nails showed very significant correlation of TSI with TFS (p = 0.0001). RF analysis was not useful in fractures with locked or reamed tibial nails. Examination of tibia with external fixation showed significant correlation (p = 0.02) of the TSI with the TFS.     

Residual intersegmental spinal mobility following limited pedicle fixation of thoracolumbar spine fractures with the fixateur interne

The Fixateur Interne has been proposed for limited pedicle fixation of thoracolumbar spine fractures with the assumption that motion in the nontraumatized spinal segments could be maintained. To date, no data exist that both localize and quantitate spinal mobility about the fractured vertebra. Voluntary maximum lateral flexion and extension radiographs were obtained on patients with unstable thoracolumbar spine fractures at a minimum of 2 years after Fixateur Interne instrumentation (implant was removed after 1 year). Residual intersegmental motion was measured at levels adjacent to both the vertebra fracture and the fixation. Fifty-nine patients were reviewed, and the posterior vertebral body angle demonstrated a mean total sagittal motion of 2.98 degrees. Cephalad and caudal to the fractured vertebra, a mean of 1.34 degrees and 3.08 degrees, respectively, of residual motion was noted; cephalad and caudal to the previously instrumented segment a mean of 3.22 degrees and 6.88 degrees, respectively, was measured. The authors conclude that residual mobility is most evident at the caudal end of the instrumented segment, removed from the fractured vertebra. The level with end plate disruption becomes essentially ankylosed, with or without a fusion.     

Food and Drug Administration regulation of spinal implant fixation devices

The role of the Food and Drug Administration in regulating medical devices generally is not well understood by physicians. The practice of medicine does not fall under Food and Drug Administrations's regulatory purview. Nevertheless, the Food and Drug Administration and its regulation of medical devices can influence physicians' activities. This article provides an overview of the scope of the Food and Drug Administration's authority and the agency's regulatory framework, with particular focus on orthopaedic medical devices as related to spinal implant devices. During the past 10 years, a regulatory dilemma has arisen surrounding the use of bone screws in the pedicles of the spine. Except for recent clearances for a limited treatment indication, the Food and Drug Administration has not cleared these devices to be labeled for pedicle screw fixation and, therefore, has restricted industry supported educational activities pertaining to this type of treatment. In spite of the Food and Drug Administration's regulatory position, physicians have chosen to use pedicle screw fixation in treating patients who have a variety of spinal disorders. This use is now considered an accepted (state of the art) medical practice by many physicians for certain spinal conditions. This article explores this specific Food and Drug Administration regulatory issue, its impact on physicians and manufacturers (especially as it pertains to medical education), and recent actions taken to resolve it.     

Protection from carcinogenic agents in work environments: considerations on Title VII of Legislative Decree 626/94

A variety of techniques are available for reconstruction of the wrist. The efficacy of wrist arthroplasty, however, is met with narrowed indications and does not enjoy the success that total joint replacement in other joints, such as the hip and knee, has enjoyed. With design improvements during the last decade, good short-term results from total wrist arthroplasty can be expected in the low-demand patient with rheumatoid arthritis. Wrist arthrodesis, either pancarpal or limited, is considered the primary surgical alternative in patients with most arthritic conditions of the wrist. The pancarpal arthrodesis is a predictable, durable alternative to a variety of post-traumatic, degenerative, or neoplastic conditions of the wrist; however, some authors report that complications may be prevalent. This procedure also may be modified and applied to the destroyed rheumatoid wrist. Overall, selection of fixation mode depends on bone quality. In an attempt to preserve motion, various limited arthrodeses of the carpus have been described. Although technically demanding, successful results may be expected, especially in conditions of carpal instability. With the current wide array of surgical alternatives, the surgeon must consider each case carefully and select the procedure that best applies to each particular situation. Furthermore, it is extremely important that the surgeon educate the patient on the limitations of each procedure.     

Fixation for distal radius fractures

Distal radius fractures are common fractures that can cause significant disability. As techniques and implants have improved, better results can be expected from internal and external fixation of complex wrist fractures. With meticulous technique, articular alignment can be secured and small articular fragments can be replaced in anatomic locations through limited open or arthroscopic techniques. Bone graft should be used liberally in comminuted articular fractures. Such procedures are demanding, however. Familiarity with the techniques described in this article will enhance the surgeon's ability to restore function in this group of patients.     

Development of preferences and processes of visual scanning in the human infant during the first 3 months of life.

Used corneal infrared photography to record the visual fixations of 24 infants (4-6 wks and 10-12 wks) exposed to simple geometric figures. Results indicate that Ss in both age groups showed decreasing fixation time to the feature that initially attracted most fixations. Young Ss limited their fixations to a smaller area of the visual field than did older Ss. This developmental change in dispersed scanning might be an essential factor in later figure preferences. There was no preference for specific features, closed figures, or any particular figure. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)