Miniplate fixation of zygomatic fractures

The availability and application of miniplate systems for the repair of displaced zygomatic fractures may effect commonly accepted guidelines for fixation of these injuries. A retrospective review of 20 patients at New York University-Bellevue Medical Center was conducted to further delineate issues concerning surgical repair and fixation. Our experience with one- and two-point fixation is evaluated and guidelines are presented.     

Stability of osteosynthesis in trochanteric fractures. Comparison of three fixation devices in cadavers

Stable trochanteric fractures were produced in 12 pairs of human cadaver femora, which were fixed by either a 135 degree Jewett nail plate, a 135 degree NoLok sliding screw/plate, or a 140 degree Hansson pin/plate. The bone-implant preparations were then subjected to 20,000 load cycles simulating full weight bearing, measuring the elastic and permanent fracture displacement. In each case, elastic displacement occurred during loading. For the Jewett-stabilized fractures, a steady increased elastic displacement, as well as permanent displacement, was seen throughout the test, causing 2/8 failures when the implant penetrated the femoral head. In the NoLok- and Hansson-stabilized fractures, there were no failures, both giving better overall stability than the Jewett device with sufficient fracture stability throughout the test.     

Stability of osteosynthesis in trochanteric fractures: Comparison of three fixation devices in cadavers

Stable trochanteric fractures were produced in 12 pairs of human cadaver femora, which were fixed by either a 135° Jewett nail plate, a 135° NoLok? sliding screw/plate, or a 140° Hansson pin/plate. The bone-implant preparations were then subjected to 20,000 load cycles simulating full weight bearing, measuring the elastic and permanent fracture displacement. In each case, elastic displacement occurred during loading. for the Jewett-stabilized fractures, a steady increased elastic displacement, as well as permanent displacement, was seen throughout the test, causing 2/8 failures when the implant penetrated the femoral head. In the NoLok?-and Hansson-stabilized fractures, there were no failures, both giving better overall stability than the Jewett device with sufficient fracture stability throughout the test.     

Stability of osteosynthesis in trochanteric fractures: Comparison of three fixation devices in cadavers

Stable trochanteric fractures were produced in 12 pairs of human cadaver femora, which were fixed by either a 135° Jewett nail plate, a 135° NoLok™ sliding screw/plate, or a 140° Hansson pin/plate. The bone-implant preparations were then subjected to 20,000 load cycles simulating full weight bearing, measuring the elastic and permanent fracture displacement. In each case, elastic displacement occurred during loading. for the Jewett-stabilized fractures, a steady increased elastic displacement, as well as permanent displacement, was seen throughout the test, causing 2/8 failures when the implant penetrated the femoral head. In the NoLok™-and Hansson-stabilized fractures, there were no failures, both giving better overall stability than the Jewett device with sufficient fracture stability throughout the test.     

Combined fixation with plates and transmalar Kirschner wires for zygomatic fractures

After repair of a fractured zygoma, the fixed zygoma occasionally becomes displaced. This phenomenon — generally called “relapse” — is a complication that can be prevented by fixing plural sites with plates. However, this impairs blood supply to the bone, which causes atrophy. To solve this dilemma, we developed a new concept for fixing the zygoma. Fractured zygomas are fixed by combining plate fixation at a single site with transmalar fixation with Kirschner wires. This secures stability of the fixed zygoma without impairing its blood supply. We evaluated the stability of fractured zygomas fixed by our method by doing dynamic experiments using simulation models. The stresses at the screw-bone interfaces were significantly reduced by the additional transmalar fixation with wire, indicating that zygomas fixed by our method are less likely to relapse than zygomas fixed with a single plate. We also reviewed the outcomes of patients treated by our method, which indicates its clinical usefulness.     

Capitellum fractures: a biomechanical evaluation of three fixation methods

OBJECTIVE: To determine the relative stability of three fixation methods for displaced capitellum fractures. DESIGN: Twelve matched pairs of embalmed humeri were divided into two equal groups and simulated capitellum fractures created. The first group compared cancellous lag screws placed in an anteroposterior direction to screws placed in the posteroanterior direction. The second group compared the Acutrac compression screw, inserted anteroposteriorly, to the more stable construct from the first test group. METHODS: All specimens were cyclically tested with simulated physiologic loading. Both displacement of the capitellum over a range of cycles and the number of cycles to failure were recorded. RESULTS: Fixation with posteroanteriorly directed cancellous lag screws was significantly more stable than anteroposteriorly directed screws at 2000 cycles (p = 0.007); loads to failure were not statistically different. Fixation by the Acutrac screws was significantly more stable than posteroanterior cancellous screws at 2000 cycles (p = 0.03). The Acutrac fixation had a higher failure load; however, this was not statistically significant. CONCLUSION: The headless screws tested in this biomechanical study provided more stable fixation of capitellum fractures in the cadaveric specimens than four-millimeter partially threaded cancellous lag screws and may do so in the clinical setting. When the cancellous lag screws were tested, insertion in the posteroanterior direction provided more stable fixation than the anteroposterior direction and has clinical benefit of not violating the articular surface. Ultimately, the decision of which method to use lies with the attending surgeon and the technique with which he or she feels most comfortable.     

A simple rapid method of fixation of unstable zygomatic fractures

A simple, effective and rapid method of fixation of unstable zygomatic fractures is described, in which a K-wire is inserted percutaneously through the prominence of the fractured malar and stabilized by further passage through both maxillae. The results of 11 cases are discussed. The method is compared with other commonly used methods of fixation, and with other techniques for internal fixation with K-wire previously described.     

A clinical evaluation of alternative fixation techniques for medial malleolus fractures

Background

Medial malleolus fractures have traditionally been managed using partially threaded screws and/or Kirschner wire fixation. Using these conventional techniques, a non-union rate of as high as 20% has been reported. In addition too many patients complaining of prominent hardware as a source of pain post-fixation. This study was designed to assess the outcomes of medial malleolar fixation using a headless compression screw in terms of union rate, the need for hardware removal, and pain over the hardware site.

Setting

Saint Louis University and Mercy Medical Center, Level 1 Trauma Centers, St. Louis, MO.

Methods

After IRB approval, we used billing records to identify all patients with ankle fractures involving the medial malleolus. Medical records and radiographs were reviewed to identify patients with medial malleolar fractures treated with headless compression screw fixation. Our inclusion criteria included follow-up until full weight bearing and a healed fracture. Follow-up clinical records and radiographs were reviewed to determine union, complication rate and perception of pain over the site of medial malleolus fixation. Sixty-four ankles were fixed via headless compression screws and 44 had adequate follow-up for additional evaluation.

Results

Seven patients had isolated medial malleolar fractures, 23 patients had bimalleolar fractures, and 14 patients had trimalleolar fractures. One patient (2%) required hardware removal due to cellulitis. One patient (2%) had a delayed union, which healed without additional intervention. Ten patients (23%) reported mild discomfort to palpation over the medial malleolus. The median follow-up was 35 weeks (range: 12–208 weeks). There were no screw removals for painful hardware and no cases of non-union.

Conclusions

Headless compression screws provide effective compression of medial malleolus fractures and result in good clinical outcomes. The headless compression screw is a beneficial alternative to the conventional methods of medial malleolus fixation.     

三种不同内固定方法治疗髌骨骨折疗效分析

目的：比较三种髌骨骨折内固定的疗效。方法：手术治疗髌骨骨折98例，其中20例采用粗丝线环形缝合固定，36例采用克氏针张力带固定，42例采用镍钛聚髌器（NT－PC）固定。结果：粗丝线环形缝合固定组：优7例，良11例，中2例；克氏针张力带固定组：优18例，良16例，中2例，镍钛聚髌器固定组；优39例，良3例。结论：三种不同内固定方法比较结果表明镍钛聚髌器固定效果最好，其优良率达100％。     

Dislocated fractures of the talus treated with biodegradable internal fixation

Six patients with a displaced fracture of the neck or body of the talus were treated using biodegradable screws and rods. During an average follow-up time of 24 (range, 18–31) months, there were no redisplacements nor collapses due to avascular necrosis. All the fractures united. The functional result was mainly dependent on the presence or absence of other injuries, being excellent in 4, good in 1 and poor in 1 patient who also had bilateral highly comminuted calcaneal fractures. Thus, biodegradable implants seem to be suitable for the fixation of displaced fractures of the talus.     

Fracture fixation with biodegradable rods. Forty-one cases of severe ankle fractures

In a prospective study of 41 patients, severe ankle fractures of Lauge-Hansen types SE III-IV, PA III, and PE III-IV were treated by open reduction and internal fixation using biodegradable self-reinforced polyglycolide cylinder-shaped rods. Disruption of the distal tibiofibular syndesmosis and/or fracture of the posterior tibial margin requiring reduction and fixation were the inclusion criteria for the study. The mean follow-up time after operation was 16 (12-32) months. Two failures of fixation necessitated reoperation. A secondary displacement of 1-2 mm of the lateral malleolus occurred in 3 cases. Transient accumulation of soluble polyglycolide mass complicated the course in 3 cases, but did not influence the radiographic or the functional result. Function became good in 30 patients. The advantage of the biodegradable implants is that they do not need to be removed at secondary operations.     

Direct osteosynthesis of fractures of the odontoid process using a biodegradable implant (B.O.P.)

The authors describe a new technique for treatment fractures of the dens. An anterior approach (technique of Boehler) is used. It provides for one-stage fusion and no additional disturbance of C1-C2 rotation. Under AP and lateral guidance the body of C2 is drilled medially, and so are the site of fracture. Then comes the gradual impaction of a conical implant of biocompatible resorbable implant [*], tip cephalad. The biopolymer is used for grafting purposes in all type of fractures of the odontoid process, which permits the latter to be fused without using screws or any other metal implant.     

Comparative strength analysis of selected osteosynthesis materials for pertrochanteric femoral fractures]

Four commercially available hip-fixation devices for stable fixation of pertrochanteric fractures were selected for a biomechanical evaluation, in order to determine, which construction would best support the load of weight-bearing in postoperative period. Intramedullar nailing by Lezius, Küntscher or Ender showed less bending moments than trifin nail-plates or extramedullar plate attachments with plate angles of 130 degrees or 95 degrees, so that bending tension of Lezius-nails were reduced compared to other implants in a proportion of 1.1,6:1,8:2,7. Whenever possible intramedullar nailing should be preferred. For extramedullar fixation of pathologic or unstable pertrochanteric fractures a double-T-plate was constructed, which shows a 3-fold load resistance of a Lezius-nail, 5-fold load-bearing of a 130 degree plate or a trifin nail combination and a 8-fold higher stress tolerance than a 95 degree-plate.     

Biomechanical evaluation of a biodegradable composite as an adjunct to internal fixation of proximal femur fractures

Internal fixation of comminuted unstable fractures of the severely osteoporotic proximal femur is sometimes supplemented with polymethyl-methacrylate (PMMA). We here report an in vitro biomechanical evaluation of a biodegradable particulate composite that might be used for similar purposes. The composite includes a matrix phase consisting of a hydrolyzable prepolymer [polypropylene fumarate (PPF)] cross-linked with methacrylate monomer, and a particulate phase consisting of tricalcium phosphate and calcium carbonate. We implanted dynamic hip screws in 22 cadaveric proximal femora and measured the yield load for an oblique force applied to the femoral head. The hip screws were then reinforced with either PMMA or the PPF composite and tested again. On the basis of analysis of variance, the average increases in yield load for PMMA and PPF reinforcement of 1,750 and 1,130 N were statistically significant (p less than 0.00005), suggesting that both materials enhance congruence between implant and bone and thereby increase the projected load-bearing area of the implant. The increase in yield force with PMMA was slightly higher than the increase with PPF (p less than 0.05), but both values after reinforcement were close (3,790 +/- 561 N for PMMA vs. 3,240 +/- 669 N for PPF). If we can demonstrate that appropriate rates of degradation, bony ingrowth, and static and fatigue properties can be achieved in vivo with this system, our data suggest that this PPF composite may have potential as an adjunct to the internal fixation of unstable fractures of the osteoporotic hip.     

Comparison of the clinical efficacy of different fixation systems for the treatment of transverse patellar fractures

Purpose: This study was designed to compare the clinical efficacy of “8” and “0” wire fixation systems combined with double-head cannulated compression screws or Kirschner wires for the treatment of transverse patellar fractures. Methods: From September 2011 to September 2018, patients with closed transverse patellar fractures treated with a double-head compression screw or Kirschner wire were included and analyzed retrospectively. Patients with patellar fractures combined with distal femoral fractures, tibial plateau fracture or preoperative lower limb dysfunction were excluded. The patients treated with the “8” tension band wire fixation system and Kirschner wire were taken as Group A; those treated with the “0” fixation system and Kirschner wire were taken as Group B; those treated with the “8” fixation system and double-head cannulated compression screw were taken as group C; and those treated with the “0” fixation system and double-head cannulated compression screw were taken as group D. Six weeks and one year after the operation and every month from the third month after the operation until the fractures healed, an X-ray examination was performed to identify fracture healing. The time of fracture healing and postoperative complications of the four groups were compared. One year after the operation, knee function was evaluated by Bostman’s score. Results: During the study period, 168 patients with patellar fractures were treated by operations, and 88 patients were excluded because the fracture type did not meet the requirements or because there were combined fractures of the distal femur or tibial plateau. As a result, 80 patients were included in this study, 20 in each group. All the patients were followed up for an average period of 12.2 months. Compared with Group A, patients in Group D presented less postoperative discomfort in the prepatellar region, quicker fracture healing, less fixation failure and better postoperative knee function scores (all p < 0.05). The incidence of internal fixation failure in Group (B+D) was lower than that in Group (A+C) (p > 0.05). Conclusion: The “0” wire fixation system combined with a double-head cannulated compression screw seems to be more beneficial than the other three fixation systems for the treatment of transverse patellar fractures.