Management of extra-articular segmental defects in long bone using a titanium mesh cage as an adjunct to other methods of fixation: a multicentre report of 17 cases.

Aims: This study reviews the use of a titanium mesh cage (TMC) as an adjunct to intramedullary nail or plate reconstruction of an extra-articular segmental long bone defect. Patients and Methods: A total of 17 patients (aged 17 to 61 years) treated for a segmental long bone defect by nail or plate fixation and an adjunctive TMC were included. The bone defects treated were in the tibia (nine), femur (six), radius (one), and humerus (one). The mean length of the segmental bone defect was 8.4 cm (2.2 to 13); the mean length of the titanium mesh cage was 8.3 cm (2.6 to 13). The clinical and radiological records of the patients were analyzed retrospectively. Results: The mean time to follow-up was 55 months (12 to 126). Overall, 16 (94%) of the patients achieved radiological filling of their bony defect and united to the native bone ends proximally and distally, resulting in a functioning limb. Complications included device failure in two patients (12%), infection in two (12%), and wound dehiscence in one (6%). Four patients (24%) required secondary surgery, four (24%) had a residual limb-length discrepancy, and one (6%) had a residual angular limb deformity. Conclusion: A titanium mesh cage is a useful adjunct in the treatment of an extra-articular segmental defect in a long bone. Cite this article: Bone Joint J 2018;100-B:646-51.

Biologic model of bone transport distraction osteogenesis and vascular response.

We developed an experimental model in the rabbit of distraction osteogenesis through bone transport that closely corresponds to the clinical use of bone transport in humans. We also applied injection angiography to study the arterial response of a limb undergoing bone transport. This model includes a proximal osteotomy and bone transport to fill in a segmental tibial diaphyseal defect. Regenerate bone formed well in the gap that was created that trailed the transport segment, and slow healing at the docking site was observed, as seen in humans. The angiographic techniques clearly revealed, by radiography and anatomic dissection, the arterial response to bone transport. The results showed that the transport segment had an arterial supply after osteotomy and after transport. They also demonstrated an extensive increase in vessels in limbs that had undergone distraction osteogenesis, an observation made clinically in humans but not well demonstrated experimentally. Furthermore, angiography showed proximal stretching and distal kinking of the major artery of the leg. This model closely resembles distraction osteogenesis through bone transport in humans and definitively demonstrates that the transport segment can maintain blood supply and remain viable during the transport process. The results of this study provide a basis for further work on factors that enhance and interfere with successful bone transport in humans.

Use of an articulated external fixator for fractures of the tibial plafond.

We performed a prospective study of forty-nine displaced fractures of the tibial plafond in forty-eight patients managed, at three centers, with an articulated external fixator placed medially across the ankle joint. Forty ankles had interfragmental screw fixation of a reduced articular fracture, and fourteen ankles had bone-grafting. The average duration of external fixation was twelve weeks. All of the fractures healed (one after delayed bone-grafting). There were no infections in any of the operative or traumatic wounds over the tibia. Two wound infections over the fibula resolved with treatment. Eight patients were managed with antibiotics for a pin-site infection, and two patients had curettage and débridement of a pin site in the hindfoot after removal of the fixator. Thirty patients (thirty-one ankles) completed two-year data sheets at an average of thirty months after the injury. The average ankle score was 67 points. Twenty-one patients had grade-0 or 1 osteoarthrosis and nine had grade-2 or 3. One ankle had been treated with an arthrodesis. These data suggest that the prevalence of early complications associated with severe fractures of the tibial plafond and their treatment can be decreased with use of an articulated external fixator combined with limited internal fixation. We concluded that this technique of external fixation is a satisfactory technique for the treatment of these fractures.

Case report. Pediatric carpal fracture dislocation.

Transcarpal fractures in children are rare in the orthopaedic literature. This is a case report of a 10-year-old boy who sustained fractures across the distal radius, scaphoid, lunate, and triquetrum with gross displacement. Treatment consisted of open reduction with internal fixation of the fractures and ligamentous repair through a combined dorsal and palmar approach. The injury healed with good wrist function but abnormal carpal development. This unusual pattern of injury is described so that it may be more readily appreciated in the future.

Pullout strength of power- and hand-driven staples in synthetic bone: effect of design parameters.

The pullout strength of power-driven and hand-driven staples of different sizes and different leg profiles was investigated in a synthetic bone model. Consistent material properties were reflected in the relatively small standard deviation in pullout strength, which was less than 7% of the mean value for power-driven and less than 10% of the mean value for hand-driven staples. An approximate linear relationship was shown to exist between the mean value of pullout strength and foam density. In paired studies, the mean value of pullout strength was significantly (p less than 0.0005) greater for the power-driven staples than similar size hand-driven staples. It was also shown that a square cross section creates significantly (p less than 0.017) more resistance to pullout force than a circular section of similar or even larger area. Although the pullout strength was not a function of the staple's width, the staple's leg length contributed to its pullout strength in a nonlinear fashion. This study suggests that narrow, long, power-driven staples of rectangular cross section have the best pullout strength for similar cross-sectional area.

Knee dislocation: initial assessment and implications for treatment.

OBJECTIVE: To evaluate bicruciate knee injuries and determine whether they should be treated as knee dislocations, especially with regard to vascular injuries. DESIGN: Retrospective. SETTING: University hospital, level 1 trauma center. PATIENTS: Fifty patients admitted between 1987 and 1994 who had sustained knee dislocations or bicruciate ligament injuries. MAIN OUTCOME MEASURES: Mechanism of injury, direction of dislocation, knee ligament injury pattern, presence or absence of periarticular fracture, presence of vascular and nerve injuries, and location of associated trauma were measured. RESULTS: Twenty-two knees had classic knee dislocations. Twenty-eight knees presented as "reduced" bicruciate ligament injuries. Vascular injury occurred just as frequently in bicruciate ligament injuries as in knee dislocations. The direction of the knee dislocation did not predict ligament injury pattern or the presence of arterial injury. CONCLUSION: Bicruciate ligament injuries are equivalent to knee dislocations with regard to mechanism of injury, severity of ligamentous injury, and frequency of major arterial injuries.

Safe extracapsular placement of proximal tibia transfixation pins.

OBJECTIVE: To identify the anatomic detail of the knee joint capsular insertion site on the proximal tibia, specifically as it relates to transfixation pins. DESIGN: Identification of capsular anatomy by anatomical dissection of cadaveric specimens, with radiography and arthroscopy of patients. SETTING: Cadaveric dissection. OUTCOME MEASURES: Anatomic observation of the capsular attachment site in relation to the tibial articular surface. RESULTS: The capsule inserts four to fourteen millimeters below the articular surface in a regular pattern. The anterior half of the circumference is close to the joint line (less than six millimeters). Posteromedially and posterolaterally, there are extensions distally to fourteen millimeters, occasionally communicating with the tibiofibular joint. CONCLUSION: Transfixing wires and half-pins can be placed in the proximal tibia without capsular penetration if kept more than fourteen millimeters from the subchondral line. If wire placement closer to the joint is required, wires should be placed in Zone 1 (the anterior half) and at least six millimeters from subchondral bone to avoid capsular penetration.

Radiographic fracture assessments: which ones can we reliably make?

OBJECTIVE: To identify the fracture characteristics that can be reliably assessed by analysis of plain radiographs of tibial plateau fractures. DESIGN: Radiographic review study. PARTICIPANTS: Five orthopaedic traumatologists served as observers. INTERVENTION: Observers made assessments based on the radiographs of fifty-six tibial plateau fractures. Precise definitions of the assessments to be made were agreed on by all observers. The tested assessments included raters' abilities to identify and locate fracture lines, identify the presence of fracture displacement and comminution, make quantitative measurements of displacement, and characterize qualitative features of fractures. For thirty-eight of the fractures that had a computed tomography (CT) scan available, assessments were repeated using both radiographs and CT scans. MAIN OUTCOME MEASURES: To characterize interobserver reliability, percentage agreement and kappa statistics were calculated for categorical variables, and intraclass correlation coefficients (ICC) were calculated for noncategorical variables. RESULTS: Reliability of the assessments varied widely. Determining the location of fracture lines had the greatest reliability, whereas the subjective assessments of fracture stability and energy showed the poorest reliability. Although the ICCs for quantitative measurements approached acceptable levels, the tolerance limits were extremely wide. The addition of a CT scan improved the reliability of most assessments, but not to a statistically significant degree. CONCLUSIONS: Many basic radiographic interpretations relied on in making treatment decisions are made variably by observers. Using experienced raters and precise definitions of fracture assessments does not guarantee a high level of agreement. Discrete assessments have higher interrater agreements than do more qualitative assessments. Quantitative measures have wide tolerance limits and, therefore, probably cannot be used reproducibly to classify fractures or make treatment decisions. We conclude the reliability of fracture classification is limited by raters' abilities to agree on basic radiographic assessments.

Mechanics of retrograde nail versus plate fixation for supracondylar femur fractures.

Two common types of internal fixations for the supracondylar femur fractures--the retrograde intramedullary nail and the 95 degrees sideplate and screw--were mechanically tested in synthetic composite femur bones to determine the quantitative differences in their inherent rigidity. The medial and lateral femoral condyles were separated by a sagittal osteotomy, and a standardized medial segmental shaft defect was created at the distal shaft. The osteotomized specimens were stabilized using one of the two implants and were tested in different modes of loading. The bending stiffness of both constructs were not significantly different in varus compression, medial bending (pure varus), and bending in flexion. The plate and screw implant was three times stiffer in lateral bending (pure valgus) and 1.2 times stiffer in valgus compression than the retrograde supracondylar nail (p < 0.01). The torsional stiffness of the plate and screw implant was significantly higher, 1.6 times that of the nail. Clinically, the most important and common cause of implant failure is varus loadings due to loss of medial cortical contact. Although the retrograde nail was less rigid in other physiologically less critical modes of loading, it had a rigidity comparable to that of the plate in varus loading. Therefore, a supracondylar nail may be considered a mechanically possible alternative to plate fixation.

Removal of intramedullary rods after femoral shaft fracture.

We are reporting a retrospective review of the removal of 60 intramedullary rods in 58 patients. All fractures had healed at the time of rod extraction. The implant was removed from 34 asymptomatic patients (36 femurs). Twenty-four patients (24 femurs) had preoperative symptoms attributed to the femoral rod. Fourteen patients had symptoms about the greater trochanter preoperatively, five patients had symptoms referable to the knee, and five had infections about the femoral implant. Problems encountered included broken rods in five femurs, one of which was not apparent on preoperative radiographs. There were six patients (six femurs) who required further hospital care for postoperative hematomas. The development of a significant hematoma was not related to the location of the fracture, the presence of interlocking devices requiring removal, the length of time since injury, the performance of this procedure as an inpatient or outpatient, or the presence or absence of a functional drain. Of the 10 patients (10 femurs) who had proximal heterotopic ossification Brooker stage 2 or greater, wound hematomas developed in four patients (40%). There were no refractures. Although there may be an indication for rod removal, we do not recommend the procedure in asymptomatic patients.

Plain radiographic interpretation in trimalleolar ankle fractures poorly assesses posterior fragment size.

Twenty-five patients with trimalleolar ankle fractures were evaluated using both conventional radiography and computed tomography (CT) to determine the size of the posterior fragment along with other fracture characteristics. Plain radiograph measurements indicated very poor inter- and intraexaminer reliability. When compared to the CT scan measurement, 54% of the plain radiographic readings revealed > 25% error. Plain radiographic interpretations erred in most cases by overrating the size of the fragment, but major underestimations also occurred. The larger size fragments showed more error than the smaller ones. This information confirms our clinical suspicion that the lateral radiograph is unreliable in assessing the posterior fragment size.

Optimizing bone screw pullout force.

Stability of internal fixation by plate and screw depends on the interface of bone and screw threads. Bone-screw thread design was tested in a synthetic bone model to determine maximum bone-screw pullout force. The model was confirmed to provide reproducible results in a clinically relevant range. Consistent material properties were reflected in the relatively small standard deviations in pullout force, which were less than 10% of mean values. As expected, major diameter was an important determinant of pullout force in a roughly linear manner. Pitch was important with a finer thread giving greater purchase. Minor diameter and the ratio of major to minor diameter had a small but significant effect on pullout force. This study was significant for establishing a good bone-screw testing model and suggesting important thread parameters in selecting or manufacturing a bone screw to optimize its holding power.

Assessment of the AO/ASIF fracture classification for the distal tibia.

OBJECTIVES: The purpose of this study was to assess the interobserver reliability and intraobserver reproducibility of the AO/ASIF and Rüedi and Allgöwer classifications for fractures of the distal tibia, and to determine the benefit of a computed tomography (CT) scan and experience on observer agreement for several fracture characteristics, including classification. METHODS: The radiographs of forty-three fractures of the distal tibia, fourteen of which had CT scans, were assessed by groups of experienced and less-experienced observers. Each case was classified according to the AO/ASIF and Rüedi and Allgöwer systems. Several other fracture characteristics also were assessed. The kappa coefficient of agreement was calculated and used to compare the interobserver reliability and intraobserver reproducibility of the classification systems and to determine the benefit of experience and CT scans. The intraclass correlation coefficient was used to assess noncategoric data. RESULTS: Interobserver and intraobserver agreements were good when classifying fractures into AO/ASIF types and significantly better than that for the Rüedi and Allgöwer system. However, agreement was poor when classifying the fractures into AO/ASIF groups. For most assessments, the experienced group tended to have higher levels of interobserver agreement, but not intraobserver agreement. Viewing the CT scans improved agreement on the percentage of articular surface involved, but it did not improve interobserver reliability or intraobserver reproducibility for either of the classification systems. CONCLUSION: The AO/ASIF classification for fractures of the distal tibia has good observer agreement at the type level, but poor agreement at the group level. Experience tends to improve interobserver agreement, but not intraobserver agreement. Viewing CT scans does not improve agreement on classification, but it tends to improve agreement on articular surface involvement.

External fixation of tibial plafond fractures: is routine plating of the fibula necessary?

OBJECTIVES: To determine the advantages and disadvantages of plating an associated fibula fracture in tibial plafond fractures treated with external fixation that spans the ankle. STUDY DESIGN: Retrospective clinical review. METHODS: The incidence of treatment complications and the outcomes achieved were compared between two groups of patients with tibial plafond fractures and associated fractures of the fibula. Both groups were treated by a uniform technique of monolateral external fixation. One group, consisting of twenty-two patients with twenty-two fractures, had plate fixation of the distal fibula and the other group, thirty-one patients with thirty-two fractures, had no fibular fixation. RESULTS: The demographics of the two groups, including sex, fracture classification, and number of open fractures, were similar. The outcome of the two groups for radiographic arthrosis and clinical ankle score, measured at minimum two-year follow-up, showed no statistically significant difference. The total numbers of complications were not statistically different between the two groups (p = 0.15), but the types of complications varied. Group I had eight complications: five fibular wound infections, two fibular nonunions, and one angular nonunion. Group II had seven complications: six angular malunions and one tibial wound infection. CONCLUSION: Open reduction and internal fixation of the fibula fracture in tibial plafond fractures treated with external fixation that spans the ankle is associated with a significant rate of complications, and good clinical results may be obtained without fixing the fibula.

Retrograde nailing of femur shaft fractures through the intercondylar notch for specific indications: 10 years experience.

Closed antegrade intramedullary nailing is the current standard of care for the treatment of femoral shaft fractures. This technique has been shown to have excellent results demonstrated by a high rate of fracture union and the low incidence of infection. However, there are complications specific to antegrade intramedullary nailing, as well as specific injury patterns that make this treatment less attractive.

Rank order analysis of tibial plafond fractures: does injury or reduction predict outcome?

We investigated the effects of severity of initial injury pattern and the quality of the articular reduction on outcome of displaced intra-articular distal tibial fractures, using a series of 25 patients who were treated with articulated external fixation and limited internal fixation, which provided a spectrum of reduction quality. Outcome was assessed by clinical ankle scores and radiographic arthrosis. The results demonstrate the rank order method to be a reliable means of stratifying severity of injury and quality of reduction. Neither injury nor reduction correlated with clinical ankle score. Reduction had a significant correlation with radiographic arthrosis. We conclude that the rank order method is useful in stratification of fracture patients, and that factors other than injury pattern and quality of articular reduction are important in determining outcome of patients with this severe articular injury.

Vascularized bone grafts.

Free vascularized bone grafts allow living bone tissue to be transplanted to replace a bone defect. The use of vascularized bone grafts requires microvascular dissection and attachment to a recipient site artery and vein, whereas rotational or pedicle grafts are moved, while still attached to their blood supply, to a new site. Conventional nonvascularized bone grafts heal by resorption and creeping substitution. The major benefits of vascularized bone grafts are more rapid and complete incorporation of the graft which provides immediate structural support, the ability of the transplanted (living) bone to form new bone, and the addition of new blood supply to the recipient area. The technique of the free vascularized fibula transplantation is described.

Heterotopic ossification.

Heterotopic ossification is a well-recognized condition frequently encountered by the orthopedic surgeon. Although typically asymptomatic, heterotopic ossification can be a complication of extreme severity. This article is a review of literature and attempts to clarify the definition, and delineates the etiology, incidence, risk factors, and current modes of prophylaxis and treatment of various types of heterotopic ossification.

Antibiotic bead production.

We are reporting a practical technique for the production of antibiotic beads for use in combating musculoskeletal infections. The technique utilizes bead molds with tobramycin powder mixed with polymethylmethacrylate on twisted wire strands to produce strands of 25 beads of various sizes. These beads are gas sterilized and available for use "off the shelf" in a manner that is much more efficient than traditional production by hand on the back table in the operating room. Our technique was also utilized at a second institution to demonstrate its efficacy at another site.

Sports fractures.

Fractures occur in athletes and dramatically influence performance during competitive and recreational activities. Fractures occur in athletes as the result of repetitive stress, acute sports-related trauma and trauma outside of athletics. The literature provides general guidelines for treatment as well as a variety of statistics on the epidemiology of fractures by sport and level of participation. Athletes are healthy and motivated patients, and have high expectations regarding their level of function. These qualities make them good surgical candidates. Although closed treatment methods are appropriate for most sports fractures, an aggressive approach to more complicated fractures employing current techniques may optimize their subsequent performance.