Clinical results of minimal screw plate fixation of forearm fractures.

Traditional plating technique for forearm fractures specifies implant selection based on achieving a minimum number of "cortices" of screw fixation on either side of the fracture. Recent biomechanical data suggest that plates with fewer screws provide equivalent strength of fixation compared with standard compression plating techniques in forearm fractures. As described in this article, we retrospectively reviewed a surgeon's experience at a regional level I trauma center to evaluate the clinical outcome of this newer fixation strategy. Seventy-eight fractured bones were plated using "minimal" screw technique--less than the traditionally recommended 6 cortices of screw purchase. Nonunion or fixation failure occurred in 7 fractures (5 patients), producing a union rate of 91% (71/78). All nonunions were atrophic and occurred in open fractures with bone loss. No construct failed because of fixation loss caused by having too few screws. Minimal screw plate technique was stable fixation, despite not having 6 cortices on both sides of the fracture. Technical emphasis should be on adequate plate length rather than number of cortices of fixation in each segment.     

Comparative strength of three methods of fixation of transverse acetabular fractures.

With the advent of percutaneously placed lag screws for fixation of acetabular fractures, this study evaluated the strength of lag screw fixation compared with traditional fixation techniques of transverse acetabular fractures. Ten formalin-treated human, cadaveric pelvic specimens with bilateral, transtectal transverse acetabular fractures were used for this study. The right acetabular fractures were fixed with a five-hole plate and four screws with the central hole spanning the posterior fracture site. The left acetabular fractures were fixed with two lag screws, one each in the anterior and posterior columns, or with a screw and wire construct stabilizing both columns. The specimens were loaded to implant failure. Stiffness, yield strength, maximum load at failure, and site of failure was recorded. The plate and screw construct showed significantly greater yield and maximum strength when compared with the two lag screws. The stiffness of the lag screw method was 39% higher than that of the plating method, but this result was not statistically significant. In addition, the plate and screw method provided significantly greater maximum strength than the screw and wire technique. The quadrilateral plate seemed to be the weakest area of fixation because 83% of the implant failures occurred in this region. In patients in whom the risks of formal open reduction and internal fixation of acetabular fractures outweigh the possible benefits, such as in patients with burns or degloved skin, the advent of computer-assisted and fluoroscopically guided percutaneous surgical techniques have been instrumental. This study showed there is greater strength of fixation with a plate and screw construct, possibly secondary to supplementary fixation distal to the quadrilateral plate. However, lag screw fixation provided relatively greater stiffness, which may account for its clinical success. Percutaneous lag screw fixation of appropriate transverse acetabular fractures is a viable option.     

Fixation of diaphyseal fractures with a segmental defect: a biomechanical comparison of locked and conventional plating techniques

BACKGROUND: Locking plates are an alternative to conventional compression plate fixation for diaphyseal fractures. The objective of this study was to compare the stability of various plating with locked screw constructs to conventional nonlocked screws for fixation of a comminuted diaphyseal fracture model using a uniform, synthetic ulna. Locked screw construct variables were the use of unicortical or bicortical screws, and increasing bone to plate distance. METHODS: This biomechanical study compared various construct groups after cyclic axial loading and three-point bending. Results were analyzed via one-way analysis of variance. Displacements after cyclical axial loading and number of cycles to failure in cyclic bending were used to assess construct stability. RESULTS: The constructs fixed by plates with bicortical locked screws withstood significantly more cycles to failure than the other constructs (p < 0.001). Significantly less displacement occurred after axial loading with bicortical locked screws than with bicortical nonlocked screws. Increased distance of the plate from the bone surface, and use of unicortical locked screws led to early failure with cyclic loading for constructs with locked screws. CONCLUSIONS: These results support the use of plating with bicortical locked screws as an alternative to conventional plating for comminuted diaphyseal fractures in osteoporotic bone. Bicortical locked screws with minimal displacement from the bone surface provide the most stable construct in the tested synthetic comminuted diaphyseal fracture model. The results of this study suggest use of plates with unicortical screws for the described fracture is not recommended.     

Minimally invasive osteosynthesis of adult tibia fractures by means of rigid fixation with anatomic locked plates

Main principle of biological fixation by minimally invasive locked plate osteosynthesis (MILPO) in lower extremity long bone fractures is relative stability which is provided by using long plate with limited number of screws. Some biomechanical studies have been reported about this issue. However, clinical studies are still missing. The aims of this retrospective extended case series were to evaluate the clinical and radiological results of adult tibia fractures treated by MILPO and the effect of plate length and screw density on complication rates. Twenty tibia fractures in 19 patients (mean age 42.3 years) operated by MILPO were reviewed. According to the AO classification, diaphyseal and metaphyseal fractures without intraarticular extensions were simple and wedge-type fractures, whereas all intraarticular fractures were comminuted. Number of screws, cortices and empty screw holes proximal and distal to the fracture, plate-span ratio (plate length divided by overall fracture length), plate-screw density (number of inserted screws divided by number of plate holes), fixation failures, delayed or nonunion, malalignment and leg length discrepancy were documented. Mean follow-up was 16 (range 12–26) months. On average, 4 screws with 6 cortices were used both proximally and distally in all fractures. Only in diaphyseal fractures, one screw hole close to the fracture was omitted. Average plate-screw density and plate-span ratio were 0.68 and 4, respectively. Mean union time was 3 months. There were no cases of delayed or nonunion on the final follow-up. Plate bending was observed in one patient who had fair result. The remaining 18 (94.8 %) patients showed good and excellent results. Satisfactory results can be achieved despite low plate-span ratio and high plate-screw density in simple and wedge-type diaphyseal fractures of the tibia. Additionally, plate-screw density can be higher at metaphysis in intraarticular fractures, in which essential point is a perfectly stable fixation that provides early motion.     

Plating of metacarpal fractures with locked or nonlocked screws,a biomechanical study: how many cortices are really necessary?

Background

Dorsal plate and screw fixation is a popular choice for metacarpal stabilization. The balance between construct stability and soft tissue dissection remains a surgical dilemma. Historically, six cortices of bone fixation on either side of a fracture were deemed necessary. This study aims to elucidate whether four cortices of locked fixation on either side of the fracture is equivalent to the current gold standard of six cortices of nonlocked fixation on either side of the fracture. If so, less dissection to insert shorter plates with fewer screws could be used to stably fix these fractures.

Methods

With biomechanical testing-grade composite Sawbones, a comminuted metacarpal fracture model was used to test two fixation constructs consisting of a standard dorsal plate and either six bicortical nonlocking screws (three screws per segment) or four bicortical locking screws (two screws per segment). Thirty specimens were tested to failure in cantilever bending and torsion.

Results

There was statistical equivalence between the locking and nonlocking constructs in cantilever bending stiffness, torsional stiffness, maximum bending load, and maximum torque.

Conclusion

The tested metacarpal fracture model had equivalent biomechanical properties when fixed with a standard dorsal plate and either six bicortical nonlocking screws or four bicortical locking screws. By utilizing fewer cortices of fixation, there will be less dissection and less soft tissue stripping during fixation of metacarpal fractures. This will also be of benefit in very proximal or distal fractures as multiple cortices of fixation are often difficult to obtain during stabilization of these challenging fractures.     

Working length and proximal screw constructs in plate osteosynthesis of distal femur fractures

BackgroundThe study purpose is to evaluate the working length, proximal screw density, and diaphyseal fixation mode and the correlation to fracture union after locking plate osteosynthesis of distal femoral fractures using bridge-plating technique.MethodsA four-year retrospective review was performed to identify patients undergoing operative fixation of distal femur fractures with a distal femoral locking plate using bridge-plating technique for the metadiaphyseal region. Primary variables included fracture union, secondary surgery for union, plate working length, and diaphyseal screw technique and configuration. Multiple secondary variables including plate metallurgy and coronal plane fracture alignment were also collected.ResultsNinety-six patients with distal femur fractures with a mean age 60 years met inclusion criteria. None of the clinical parameters were statistically significant indicators of union. Likewise, none of the following surgical technique parameters were associated with fracture union: plate metallurgy, the mean working length, screw density and number of proximal screws and screw cortices. However, diaphyseal screw technique did show statistical significance. Hybrid technique had a statistically significant higher chance of union when compared to locking (p = 0.02). All proximal locking screw constructs were 2.9 times more likely to lead to nonunion.ConclusionsPlating constructs with all locking screws used in the diaphysis when bridge-plating distal femur locking plates were 2.9 times more likely to incur a nonunion. However, other factors associated with more flexible fixation constructs such as increased working length, decreased proximal screw number, and decreased proximal screw density were not significantly associated with union in this study.     

Biomechanical testing of the LCP--how can stability in locked internal fixators be controlled?

New plating techniques, such as non-contact plates, have been introduced in acknowledgment of the importance of biological factors in internal fixation. Knowledge of the fixation stability provided by these new plates is very limited and clarification is still necessary to determine how the mechanical stability, e.g. fracture motion, and the risk of implant failure can best be controlled. The results of a study based on in vitro experiments with composite bone cylinders and finite element analysis using the Locking Compression Plate (LCP) for diaphyseal fractures are presented and recommendations for clinical practice are given. Several factors were shown to influence stability both in compression and torsion. Axial stiffness and torsional rigidity was mainly influenced by the working length, e.g. the distance of the first screw to the fracture site. By omitting one screw hole on either side of the fracture, the construct became almost twice as flexible in both compression and torsion. The number of screws also significantly affected the stability, however, more than three screws per fragment did little to increase axial stiffness; nor did four screws increase torsional rigidity. The position of the third screw in the fragment significantly affected axial stiffness, but not torsional rigidity. The closer an additional screw is positioned towards the fracture gap, the stiffer the construct becomes under compression. The rigidity under torsional load was determined by the number of screws only. Another factor affecting construct stability was the distance of the plate to the bone. Increasing this distance resulted in decreased construct stability. Finally, a shorter plate with an equal number of screws caused a reduction in axial stiffness but not in torsional rigidity. Static compression tests showed that increasing the working length, e.g. omitting the screws immediately adjacent to the fracture on both sides, significantly diminished the load causing plastic deformation of the plate. If bone contact was not present at the fracture site due to comminution, a greater working length also led to earlier failure in dynamic loading tests. For simple fractures with a small fracture gap and bone contact under dynamic load, the number of cycles until failure was greater than one million for all tested constructs. Plate failures invariably occurred through the DCP hole where the highest von Mises stresses were found in the finite element analysis (FEA). This stress was reduced in constructions with bone contact by increasing the bridging length. On the other hand, additional screws increased the implant stress since higher loads were needed to achieve bone contact. Based on the present results, the following clinical recommendations can be made for the locked internal fixator in bridging technique as part of a minimally invasive percutaneous osteosynthesis (MIPO): for fractures of the lower extremity, two or three screws on either side of the fracture should be sufficient. For fractures of the humerus or forearm, three to four screws on either side should be used as rotational forces predominate in these bones. In simple fractures with a small interfragmentary gap, one or two holes should be omitted on each side of the fracture to initiate spontaneous fracture healing, including the generation of callus formations. In fractures with a large fracture gap such as comminuted fractures, we advise placement of the innermost screws as close as practicable to the fracture. Furthermore, the distance between the plate and the bone ought to be kept small and long plates should be used to provide sufficient axial stiffness.     

Die Stabilität von distalen Radiusfrakturen mit volaren winkelstabilen Plattenosteosynthesen

Background

Distal radius fractures continue to show significant complication rates after operative treatment with locked plating. Failure occurs by screw loosening or screw penetration in the distal fragment. Placement of additional screws may enhance the stiffness of fracture fixation. The aim of this study was to determine the fatigue properties of different screw configurations in distal radius plate osteosynthesis with biomechanical tests and finite element analysis (FEA).

Material and methods

Unstable distal radius fractures were created in 12 human cadaveric bone specimens and were fixed with volar locking plates. Group 4SC was fixed with four screws in the distal row and group 6SC with two additional screws the row below. Dynamic loading was applied physiologically. The radial shortening, the angulation of the distal fragment and the failure mechanism were determined by experimental tests and were further elucidated by FEA.

Results

Group 6SC showed a significantly lower radial shortening and inclination. Breakage of the screws within the plate was noted in group 4SC, while moderate screw penetration was observed in group 6SC. FEA confirmed the biomechanical tests. In group 4SC elevated von Mises strain in the locking mechanism explained the inclination of the screws and the distal fragment. The elastic strain in group 6SC was increased at the screw-bone interface which explained the resulting screw penetration.

Conclusion

The failure mechanism in volar plating of distal radius fractures depended on the number of screws and their configuration. Using two more screws increases construct stiffness and angular stability under dynamic loading. However, increased stiffness also promoted screw penetration mainly in osteoporotic bone. Compared to screw penetration, loss of reposition and inclination of the distal fragment observed in the 4SC configuration is more likely to result in clinical complications.     

Biomechanics of locked plates and screws

OBJECTIVE: To review the biomechanical principles that guide fracture fixation with plates and screws; specifically to compare and contrast the function and roles of conventional unlocked plates to locked plates in fracture fixation. We review basic plate and screw function, discuss the design rationale for the new implants, and examine the biomechanical evidence that supports the use of such implants. DATA SOURCES: Systematic review of the per reviewed English language orthopaedic literature listed on PubMed (National Library of Medicine online service). STUDY SELECTION: Papers selected for this review were drawn from peer review orthopaedic journals. All selected papers specifically discussed plate and screw biomechanics with regard to fracture fixation. PubMed search terms were: plates and screws, biomechanics, locked plates, PC-Fix, LISS, LCP, MIPO, and fracture fixation. DATA SYNTHESIS: The following topics are discussed: plate and screw function-neutralization plates and buttress plates, bridge plates; fracture stability-specifically how this effects gap strain and fracture union, conventional plate biomechanics, and locking plate biomechanics. CONCLUSIONS: Locked plates and conventional plates rely on completely different mechanical principles to provide fracture fixation and in so doing they provide different biological environments for healing. Locked plates may increasingly be indicated for indirect fracture reduction, diaphyseal/metaphyseal fractures in osteoporotic bone, bridging severely comminuted fractures, and the plating of fractures where anatomical constraints prevent plating on the tension side of the bone. Conventional plates may continue to be the fixation method of choice for periarticular fractures which demand perfect anatomical reduction and to certain types of nonunions which require increased stability for union.     

Comparison of metacarpal plating methods

PURPOSE: Most metacarpal fractures are stable and can be treated with nonsurgical stabilization. However, some metacarpal fractures are treated with open reduction and internal fixation because of an open fracture, instability, or multiple fractures. Newer plate designs have emerged that allow a shorter plate and screw construct. We sought to determine the relative strength of 3 different methods of metacarpal plating for unstable fractures. METHODS: We tested our hypothesis in a transverse metacarpal fracture model using fourth-generation, biomechanical testing grade composite sawbones (Sawbones; Pacific Research Laboratories, Vashon, WA). The metacarpals were divided into 3 groups of 15 bones. Group 1 was plated with a standard 6-hole, 2.3-mm plate with 6 nonlocking bicortical screws in standard AO fashion. Group 2 was plated with a 6-hole, double-row, 3-dimensional (3D) plate with 3 nonlocking screws on either side of the fracture aiming for convergence of the screws. Group 3 was plated with a 2.4-mm plate using 6 nonlocking screws and standard AO technique. The metacarpals were then tested to failure in cantilever bending mode. RESULTS: All constructs broke through the bone. No plate failure or screw pullout was seen. Group 1 had a load to failure of 264 N +/- 14. Group 2 had a load to failure of 302 N +/- 17. Group 3 had a load to failure of 274 N +/- 20. The load to failure was highest in group 2 (3D plate). All differences were statistically significant. CONCLUSIONS: All 3 methods produced a strong construct. The load to failure was highest in group 2 (3D plate). Double-row plates with converging screws provide adequate or superior strength of fixation when compared with standard plate constructs.     

Comparison of plate and screw fixation and screw fixation alone in a comminuted talar neck fracture model

BACKGROUND: Talar neck fracture fixation has been studied in noncomminuted fracture models, but no large clinical series of comminuted fracture patterns have been published and no biomechanical studies have compared plate fixation with screw fixation in comminuted talar neck fractures. METHODS: Nine matched pairs of fresh frozen talar specimens were stripped of soft tissue and mounted in a cylindrical jig. The talar neck was fractured using a dorsally directed shear force at a rate of 200 mm/min, and dorsal comminution was simulated by removing a 2-mm section of bone from the distal fracture fragment. One specimen from each pair was fixed with either two solid 4.0-mm partially threaded cancellous screws posterior-to-anterior just lateral to the posterior process of the talus or with a four-hole 2.0-mm minifragment plate contoured to the lateral surface of the talar neck and secured with 2.7-mm screws. A 2.7-mm fully threaded cortical screw was placed medially using a lag technique. The specimens were then loaded to failure with a dorsally directed force at a rate of 200 mm/min. Failure was defined as the load producing 2 mm of displacement. A Student's t-test analysis was used with significance set at p < or = 0.05. RESULTS: Posterior-to-anterior screw fixation had a statistically significant higher load to failure than plate fixation (p < 0.05). Mean load to failure for the screw group was 120.7 +/- 68.5 N and 89.7 +/- 46.6 N for the plating group. CONCLUSIONS: Plate fixation may offer substantial advantages in the ability to control the anatomic alignment of comminuted talar neck fractures, but it does not provide any biomechanical advantage compared with axial screw fixation. Further, the fixation strength of both methods was an order of magnitude lower than those found in previous studies of noncomminuted fractures.     

Technical aspects of bridge plating for pediatric femur fractures

Bridge plating for the adult orthopedic trauma population has been increasing over the last few years. The technique, used in comminuted fractures, allows for stable internal fixation while reducing blood loss and the need for fracture site exposure. We have applied the technique of bridge plating for comminuted diaphyseal femur fractures in the pediatric trauma population due to the limitations of fracture treatment options in these patients. The use of 4.5-mm narrow low-contact dynamic compression plate plates with minimal exposure for plate entry and percutaneous screw placement has greatly facilitated the treatment of these fractures. The technique creates a stable mode of fixation while maximizing biologic fracture healing potential and also permits early patient mobilization.     

Biomechanical evaluation of locking plate radial shaft fixation: unicortical locking fixation versus mixed bicortical and unicortical fixation in a sawbone model

PURPOSE: Compression plating is a commonly accepted technique for treating diaphyseal forearm fractures. The purpose of this study was to evaluate the stabilizing effects of two hybrid fixations that replace the end screws of a locked unicortical fixation with bicortical (locked or unlocked) screws and to compare these hybrid fixations to an unlocked bicortical fixation. METHODS: Sixteen composite radius sawbones were equally divided into 4 groups. We performed a midshaft osteotomy and plate fixation on the volar surface with 1 of 4 different constructs: 3 unlocked bicortical screws on each side (unlocked bicortical), 3 locked unicortical screws on each side (locked unicortical), or with 2 unicortical locked screws near the fracture and 1 bicortical unlocked (unlocked hybrid) or locked (locked hybrid) screw distant from the fracture on each end (LCP system, Synthes USA, Paoli, PA). Specimens were tested in nondestructive 4-point bending and torsion on a servo-hydraulic material testing system. The construct stiffness was obtained from the linear portion of the load-displacement curves after 3 cycles of preconditioning. The results from all groups were compared using analysis of variance and post hoc Bonferroni tests. RESULTS: Under torsional loads, replacing the end screws of a locked unicortical configuration with bicortical screws significantly improved the construct stiffness: 57.6% increase for the locked screws and 51.6% increase for the unlocked. In anteroposterior (AP) bending, the highest improvement over the locked unicortical configuration came from the locked hybrid constructs (42.9% increase). When compared with the unlocked bicortical configuration, both hybrid constructs provide equivalent stability in torsion but superior stability in AP bending. CONCLUSIONS: Replacing a single set of unicortical locked screws with locked or unlocked bicortical screws distant from the fracture site improves torsional stability of the construct by more than 50%, giving stability equal to standard unlocked plating. The hybrid fixation, however, with locked bicortical end screws has the best stability in AP bending.     

Current concepts in pediatric femur fracture treatment

Femoral neck fractures require urgent evacuation of intracapsular hematoma, anatomic reduction, and secure fixation with screws and cast immobilization. Extracapsular trochanteric and subtrochanteric fractures are best treated by fixed angle devices (locked plates or dynamic screw and side plate). "Length stable" low energy shaft fractures with minimal displacement or < 2 cm of shortening on presentation, are treated with one-leg spica casting (if the patient weighs < or = 50 lb. "transportable"). Unstable, complex (multifragmentary) and significantly displaced high energy shaft fractures are treated operatively. Transverse or short oblique shaft fractures in patients < 12 years may be treated with elastic intramedullary nails. Bridge plating will provide better stability in complex fractures. Children > 12 years have less risk of vascular disturbance to the proximal physis, and should have lateral transtrochanateric entry locked rigid nails. Fractures with severe soft tissue injuries could be temporized with external fixation. Distal physis and epiphyseal injuries require anatomical reduction and smooth wires and/or screw fixation (placed in such a way as to minimize further damage to the physis) and need to be augmented with a brace. Leg-length discrepancy is not a significant clinical problem in operatively treated patients. We recommend hardware removal after complete fracture healing, usually in 6 to 12 months. Implants left in the growing child could become buried deep inside of the bone, or cause "periprosthetic" fractures and/or eventually impede adult reconstruction. Minimal risks are reported for hardware removal in healthy patients with healed fractures (4 cortices bridged).     

Oblique screws at the plate ends increase the fixation strength in synthetic bone test medium

OBJECTIVE: To test the hypothesis that oblique screws at the ends of a plate provide increased strength of fixation as compared to standard screw insertion. DESIGN: Biomechanical laboratory study in synthetic bone test medium. METHODS: Narrow 4.5-mm stainless steel low-contoured dynamic compression plates were anchored with cortical screws to blocks of polyurethane foam. The fixation strength in cantilever bending (gap closing mode) and torsion was quantified using a material testing system. Different constructs were tested to investigate the effect of the screw orientation at the end of the plate (straight versus oblique at 30 degrees), the plate, and bridging length as well as the number of screws. RESULTS: An oblique screw at the plate end produced an increased strength of fixation in all tests; however, the difference was more significant in shorter plates and in constructs with no screw omission adjacent to the fracture site. Both longer plates and increased bridging length produced a significantly stronger construct able to withstand higher compression loads. Under torsional loading, the fixation strength was mainly dependent on the number of screws. CONCLUSIONS: The current data suggest that when using a conventional plating technique, plate length is the most important factor in withstanding forces in cantilever bending. With regard to resisting torsional load, the number of screws is the most important factor. Furthermore, oblique screws at the ends of a plate increase fixation strength.     

Percutaneous screw configuration versus perimeter plating of calcaneus fractures: a cadaver study

BACKGROUND: Percutaneous screw configuration has been used clinically to reduce the high rate of wound complications associated with the extensile approach of standard open reduction and internal plate fixation. The aim of this cadaveric biomechanical study was to compare the strength of the standard perimeter plating with that of the percutaneous screw configuration for a Sanders type-2B calcaneus fracture. MATERIALS AND METHODS: Ten pairs of fresh-frozen cadaveric lower limbs were prepared and osteotomized to create a Sanders type-2B fracture. Of each pair, one specimen underwent open reduction and internal fixation with standard perimeter plating; the other was stabilized with the percutaneous screw configuration. Each foot was compressed axially via the talar dome (1 mm/sec) until failure occurred. Differences in treatment groups were analyzed for significance (p < 0.05) using paired t-tests. RESULTS: Construct stiffness was 158 +/- 85 and 113 +/- 60 N/mm for the plate and percutaneous fixation, respectively (p = 0.18). Failure occurred at an average of 1156 +/- 513 and 1064 +/- 540 N for the plate and percutaneous construct, respectively (p = 0.65). CONCLUSION: The results suggest that open reduction and internal fixation with percutaneous screw configuration for Sanders type-2B calcaneus fractures provides a strength similar to that of perimeter plating. CLINICAL RELEVANCE: Percutaneous screw fixation of calcaneus fractures may provide fracture reduction similar to plate fixation.     

Combination of hook plate and tibial pro-fibular screw fixation of osteoporotic fractures: a clinical evaluation of operative strategy

BACKGROUND: Internal fixation of osteoporotic ankle fractures is technically difficult and may fail because of unreliable purchase. This study was undertaken to determine if a combination of a hook plate and tibial pro-fibular screws can provide secure fixation until fracture union. METHODS: Thirty-one patients between the ages of 55 and 90 years had open reduction and internal fixation of ankle fractures between April, 2001, and April, 2003. Sixteen patients with an average age of 71.4 years had ankle fracture fixation with a combination of hook plate and tibial pro-fibular screws for the distal fibular fracture, and 15 patients with an average age of 71.9 years had fixation of their ankle fractures with standard fixation technique using AO/ASIF principles but no tibial pro-fibular screws. All patients were followed with clinical and radiologic assessment at 2 weeks, 6 weeks, and 12 weeks postoperatively. At an average of 15.8 months after injury, patients also completed a mailed questionnaire with the Olerud-Molander ankle score and the AOFAS ankle-hindfoot score for preoperative and postoperative status. RESULTS: All patients who had tibial pro-fibular screw fixation had fracture union without hardware failure or complications. In the standard fixation group two patients had wound breakdown and one had a valgus malunion with screw pull out. The AOFAS and Olerud-Molander scores for the standard open reduction and internal fixation were 57.3 and 82.8 before injury and 37 and 43.8 postoperatively, respectively. The AOFAS and Olerud-Molander scores for the hook plate and tibial pro-fibular fixation group were 55.9 and 81.3 before injury and 42.4 and 50.3 postoperatively, respectively. CONCLUSIONS: The combination of hook plate and tibial pro-fibular screws in osteoporotic ankle fractures in a series of patients has not been reported before. This novel technique provides stable fixation for osteoporotic ankle fractures in elderly patients until union is achieved with good clinical scores.     

Syndesmosis fixation: a comparison of three and four cortices of screw fixation without hardware removal

BACKGROUND: Great variability exists in methods of stabilization for syndesmotic disruptions of the ankle. We hypothesized that syndesmotic screw fixation with 3.5-mm fully threaded cortical screws through either three or four cortices would have similar strength and rate of mechanical failure and that retention of screws after fracture healing would not result in adverse clinical symptoms. METHODS: In a prospective, surgeon-randomized study at a Level-one trauma center, 127 patients with syndesmotic disruptions were treated surgically. Seven patients were lost to followup, leaving 120 for review. Syndesmotic disruptions were stabilized with 3.5-mm fully threaded cortical screws placed through three or four cortices. Screws were removed only if symptomatic. Outcome criteria were screw failure, loss of reduction, and need for hardware removal. RESULTS: Fifty-nine patients received fixation through three cortices and 61 patients received fixation through four cortices. Mean follow-up was 150 days. In the group with stabilization through three cortices, hardware failure occurred in five patients (8%) and three had a loss of reduction. In the group with stabilization through four cortices, hardware failure occurred in four patients (7%); all were asymptomatic and did not require screw removal. There was no loss of reduction in that group. Comparing the two groups using binary logistic analysis, there was no difference in loss of reduction (p = 0.871), screw breakage (p = 0.689), or need for hardware removal (p = 0.731). CONCLUSION: The data suggest that either three or four cortices of fixation can be used when stabilizing syndesmotic injuries of the ankle. There was a trend towards higher loss of reduction in the group with tricortical fixation when weightbearing restrictions were not followed. Retention of the syndesmotic screws, even with mechanical failure, does not pose a clinical problem. Weightbearing can be allowed at 6 to 10 weeks without routine removal of screws.     

一期后路经关节螺钉联合前路钢板固定治疗下颈椎骨折脱位

目的 探讨一期后路经关节螺钉联合前路钢板固定技术治疗下颈椎骨折脱位的效果. 方法 自2005年10月至2007年5月对12例下颈椎骨折脱位患者采用一期前后路联合手术.单纯脱位者,先行后路复位经关节突螺钉固定,再改行前路椎间隙减压,植骨融合,钢板内固定;椎体骨折伴脱位者,前路先行椎体次全切除,植骨融合,钢板内固定,然后行后路经关节螺钉固定脱位节段,小关节间行植骨融合.术前ASIA分级:A级21例,B级6例,C级3例,D级1例. 结果 12例患者获6～21个月(平均14.8个月)随访,椎间及小关节间植骨全部愈合.无螺钉松动及神经、血管并发症.术后除1例完全性瘫痪患者神经功能无恢复外,其余11例均有一级以上恢复.术后ASIA分级:A级1例,B级1例,C级4例,D级4例,E级2例. 结论 下颈椎经关节螺钉联合前路钢板固定融合术,具有操作简单安全、固定可靠、植骨融合率高等优点,是治疗下颈椎骨折脱位较为理想的术式.     

S1 pediculoiliac screw fixation in instabilities of the sacroiliac complex: biomechanical study and report of two cases

OBJECTIVE: A new technique for posterior sacroiliac fixation is described and compared with conventional techniques. PATIENTS/MATERIAL AND METHODS: A patient with sacral alar fracture (zone 1) and another one with sacroiliac joint instability due to tuberculous infection underwent fixation using screws placed in the S1 pedicle and the iliac bone. Vertical stability of the new technique also was investigated using polyurethane pelvic bone analogs and compared with anterior double plating (group P) and iliosacral screw fixation (group ISS) techniques. RESULTS: Healing was obtained and reduction was maintained in both patients on the final follow-up examination at 2 years postoperatively. Vertical loading tests revealed that failure loads within the first 10 mm of displacement of the new pediculoiliac screw fixation technique (group PIS) was higher than plating (P = 0.03) and lower than ISS techniques (P = 0.002). Ultimate failure load of the PIS technique was slightly higher than plating (P = 0.277) and lower than ISS techniques (P = 0.003). With the addition of an iliosacral screw to the pediculoiliac screw construction (PIS+ISS), the PIS technique became more stable in early (P = 0.110) and ultimate failure loads (P = 0.003). CONCLUSIONS: Pediculoiliac screw fixation for sacroiliac joint disruptions and zone I sacrum fractures using iliac and S1 pedicle screws is a new and effective alternative for obtaining and maintaining anatomic reduction.