One-point Fixation Research Articles

A comparison of one point versus two point fixation in the management of zygomatico-maxillary complex fractures

The zygomaticomaxillary complex (ZMC) fractures are highly frequent injuries. There is a variety of operative techniques for fixation of ZMC fractures, with no consensus about the best technique. We aim to compare one-point versus two-point fixation of tripodal zygomatic fractures. This study was carried out on 34 patients admitted to the trauma unit in Sanjay Gandhi Institute of Trauma and Orthopaedics in the period from September 2022 to August 2023. Patients were divided into two groups (group 1; one-point fixation, and group 2; two- point fixation). When compared to the one-point fixation group, only 14 patients had substantial stability with a P-value of <0.05 being statistically significant. In contrast, nearly all patients in the two-point fixation group had higher stability. In the two-point fixation group, nearly all patients had a post-operative scar; in the one-point fixation group, however, only two patients had the same scar, and the mouth opening was also improved. In two-point fixation, paraesthesia was observed in nearly seven patients, while in one-point fixation, it was present in only two patients.The one-point fixation technique for tripodal ZMC fractures is considered effective as the two-point fixation technique; and it offers advantages of scarless operation, reduced operation time, fewer complications, and lower cost.

Role of finite element analysis for selection of single point fixation in zygomaticomaxillary complex fracture

BackgroundOne-point fixation was superior to the two and three-points fixation in minimally displaced zygomaticomaxillary complex (ZMC) fracture regarding the cost, invasiveness, scaring, number of wounds, and operation time. Accordingly, this study aimed to predict which one-point fixation is the most stable in managing minimally displaced ZMC fracture.Material & methodsThis study simulated the different one-point fixation approaches on three ZMC models after fracture reduction and application of all forces exerted on the fractured area. The findings were represented as stress impact on the ZMC fracture and plating system as well as the inter-fragments micro-motion.ResultsThe von misses stresses of plates for the zygomaticofrontal, infra-orbital rim, and zygomaticomaxillary buttress model were (66.508, 1.285, and1.16 MPa) respectively. While the screws’ von misses for the infraorbital rim, zygomaticofrontal, and zygomaticomaxillary buttress models were (13.8, 4.05, and 1.60 MPa) respectively. Whereas, the maximum principles stress at zygomaticofrontal, zygomaticomaxillary buttress, and infraorbital rim models were (37.03, 37.01, and 34.46 MPa) respectively. In addition, the inter-fragment micro-motion for zygomaticomaxillary buttress, infraorbital rim, and zygomaticofrontal models were (0.26, 0.25, and 0.15 mm) respectively.ConclusionOne-point fixation at zygomaticomaxillary buttress is the preferred point because it is exposed to low stresses, and the inter-fragment micro-motion is within the approved limit with the elements in the same direction of fixation which indicates the rigid fixation. In addition, it is less palpable and scarless.Trial registrationclinical trial.gov (NCT05819372) at 19/04/2023.

Refixation of the anterior cruciate ligament: A biomechanical analysis of suture techniques in a porcine model.

Refixation of acute anterior cruciate ligament (ACL) tears represents an increasingly popular treatment option. Systematic evaluations of various suture technique parameters are still pending. We therefore aimed to evaluate the mechanical pull-out outcomes of various suture methods for optimization of ACL refixation. Sixty fresh knees from mature domestic pigs were dissected and the femoral attachment of the ACL was peeled off. The 60 knees were divided in 10 groups and sutured as follows: (A) one suture (1, 2, 4 and 6 passes), (B) two sutures (2, 4 and 6 passes each; sutures knotted together as a loop) and (C) two sutures (2, 4 and 6 passes each, sutures knotted separately). The pull-out test was conducted using a validated electrodynamic testing machine. First occurrence of failure, maximum pull-out load and stiffness were measured. Suture failure was defined as pull-out of the ACL. Two-point fixation, using two sutures, with at least two passes, showed the most favourable biomechanical stability. The maximum pull-out load was significantly higher with two sutures (529.5 N) used compared to one (310.4 N), p < 0.001. No significant differences were found for maximum pull-out loads between two-point fixation versus one-point fixation but stiffness was significantly higher with two-point fixation (107.4 N/mm vs. 79.4 N/mm, p < 0.001). More passes resulted in higher maximum pull-out loads. The results suggest using two independent sutures, refixed separately and at least two suture passes, is appropriate for ACL refixation. More suture passes provide additional strength but are technically challenging to achieve during surgery. Level IV.

Evaluation of one-point fixation surgery with computer-aided root mean square deviation in zygomaticomaxillary complex fractures

Aims: Our paper aimed to present the results of the one-point fixation method in zygomaticomaxillary fractures by computer-aided mirror image superimposition with root mean square (RMS) deviation.&#x0D; Methods: One-point fixation performed zygomaticomaxillary complex fracture patients (n=18) by one surgeon were included in our study. Virtual 3D data of preoperative and postoperative CT-scan images was obtained by Slicer software. Sagittal plan mirror image superpositioning were used to obtain RMS data by Slicer. Mirror image superimposition of the undamaged side to the broken side in preoperative CT-scan imaging was referred as group B or broken group. Superposition of the repaired side’s postoperative imaging to the preoperative broken side was measured as group R or repair group in order to examine zygomatic bone’s postoperative spatial location. Superpositioned mirror 3D images of the non-traumatic side onto post-fixation 3D in postoperative data was measured as group M or mirror group. RMS deviation values of the groups obtained by Slicer were statistically compared.&#x0D; Results: Shapiro-Wilk test of groups were demonstrated normal distribution of the data for each group with no difference (p&gt;0.05). In order to compare between groups, paired t-test covariance analysis were shown statistically similar data distrubition between experimental groups (p&gt;0.05).&#x0D; Conclusion: Considering the nature of maxillofacial surgery, which disapproves even millimetric errors, we believe that the mean square root deviation will become standard as it allows three-dimensional evaluation and precise mathematical measurements. Besides, in accordance with the recent literature, this study might pay the way for future studies that would increase the usage of the one-point fixation method conducted on larger case series, as this method prevents lower eyelid complications without a visible scar.

Is three-point fixation needed to mechanically stabilize zygomaticomaxillary complex fractures?

Fixation is critical in zygomaticomaxillary complex (ZMC) fractures to avoid malunion; however, controversy exists as to how much hardware is required to achieve adequate stability. Current fixation regimens may not represent the minimum stabilization needed for uneventful healing. Craniomaxillofacial (CMF) computational models have shown limited load transmission through the infraorbital rim (IOR), and a previous experimental study of ZMC fractures has suggested that IOR plating does not alter CMF bone strain patterns. This study aimed to measure the impact of stabilization on fracture site displacement under muscle loading, testing the hypothesis that three-point fixation is not critical for ZMC fracture stability. Four ZMC complex fractures were simulated on two cadaveric samples and stabilized with three-point plating. Displacements simulating mouth openings of 20mm and 30mm were applied to the mandible using a custom apparatus. Fracture gap displacement under load was measured at multiple points along each fracture line, and bone strain was captured using a combination of uniaxial and rosette gauges. Data capture was repeated with the IOR plate removed (two-point fixation) and with the zygomaticomaxillary plate removed (one-point fixation). Fracture displacement under muscle loading was consistent, with gaps of less than 1mm in 95% of cases (range 0.05-1.44mm), reflecting clinical stability. Large variabilities were observed in the strain measurements, which may reflect the complexity of CMFS load patterns and the sensitivity of strain values to gauge placement. This study supports the concept of hardware reduction, suggesting that two-point (or even one-point) fixation may provide sufficient stability for a ZMC fracture under applied muscle loading.

One-point versus two-point fixation in the management of zygoma complex fractures

BackgroundThe treatment of zygoma complex fractures is of crucial importance in the field of plastic surgery. However, surgical methods to correct zygoma complex fractures, including the number of fixation sites, differ among operators. Although several studies have compared two-point and three-point fixation, no comparative research has yet been conducted on one-point versus two-point fixation using computed tomography scans of surgical results. Therefore, the present study aimed to address this gap in the literature by comparing surgical results between one-point and two-point fixation procedures.MethodsIn this study, we randomly selected patients to undergo surgery using one of two surgical methods. We analyzed patients with unilateral zygoma complex fractures unaccompanied by other fractures according to whether they underwent one-point fixation of the zygomaticomaxillary buttress or two-point fixation of the zygomaticomaxillary buttress and the zygomaticofrontal suture. We then made measurements at three points—the zygomaticofrontal suture, inferior orbital wall, and malar height—using 3-month postoperative computed tomography images and performed statistical analyses to compare the results of the two methods.ResultsAll three measurements (zygomaticofrontal suture, inferior orbital wall, and malar height) showed significant differences (p<0.05) between one-point and two-point fixation. Highly significant differences were found for the zygomaticofrontal suture and malar height parameters. The difference in the inferior wall measurements was less meaningful, even though it also reached statistical significance.ConclusionUsing three parameters in a statistical analysis of imaging findings, this study demonstrated significant differences in treatment outcomes according to the number of fixations. The results indicate that bone alignment and continuity can be achieved to a greater extent by two-point fixation instead of one-point fixation.

Fixation at the Inferior Orbital Rim in Medially Rotated Zygomatic Complex Fractures.

Background:Zygomatic complex fractures are quadri-pod fractures because of the involvement of the zygomaticotemporal, zygomaticomaxillary, zygomaticofrontal, and zygomaticosphenoid junctions. The need to address one or more fixation points of these four articulations mainly depends on the degree of displacement. In this article, the authors present a series of medially rotated zygomatic complex fractures to demonstrate that one-point fixation at the inferior orbital rim (IOR) is sufficient in most cases.Methods:This is a retrospective study of all medially rotated zygomatic complex fractures treated by the authors over the last 4 years.Results:The patients were six men with a mean age of 41 years. All patients sustained medially rotated zygomatic complex fractures. Three patients had symptomatic orbital floor defects. One patient had concurrent displaced superior orbital rim fracture. Surgery was done using the transconjunctival approach. A titanium mesh was used to fix the IOR. For orbital floor reconstruction, the same titanium mesh was extended into the floor to cover the defect. The patient with concurrent superior orbital rim fracture required a second point of fixation at the lateral orbital rim.Conclusions:Single-point of fixation at the IOR is sufficient in most medially rotated zygomatic complex fractures as long as there is minimal displacement at other fracture points. Some of these patients may have symptomatic orbital floor defects. Simultaneous fixation of the IOR and orbital floor reconstruction may be done via a transconjunctival approach.

Finite Element Simulation of Displacement of the Broken Zygoma and Forces Exerted to the Complex After Fixation with Resorbable and Non-Resorbable One-Point Mini-Plates and Applying Normal or Severe Occlusal Loads

Background: ZMC fractures are the second most common trauma of the face. Therefore, their treatment (including methods of fixation) is of clinical significance. Objectives: Due to the lack of studies on many resorbable and non-resorbable fixations of the zygoma, this finite element analysis assessed for the first time displacements and dynamics of the zygoma fixed using three 1-point resorbable and three non-resorbable plates under normal and severe mastication forces. Methods: After creating the 3Dmodel of the zygoma and its adjacent bones based on a CT scan of amale patient, with linear fractures but without severe dislocations, three one-point resorbable and three similar one-point non-resorbable mini-plates were used to fix the zygoma with miniscrews. The zygomaticomaxillary buttress (ZMB), infraorbital rim, and frontozygomatic (FZ) suture were stabilized using L-shaped four-hole, curved five-hole, four-hole miniplates, respectively. The simulated zygoma was subjected to 150N and 750N loads. Minimum and maximum of stresses, strains, displacements, and rotational displacements of the zygoma were measured. Results: All four parameters were much smaller in non-resorbable fixations compared to resorbable ones. In severe maxillary force, the parameters stress, strain, and displacement increase considerably. Among these, FZ might cause smaller displacements. Resorbable plates might not be optimum choices for one-point fixation of cases with the heavy mastication loads.

Sensor-actuator component for a Floating Mass Transducer-based fully implantable hearing aid

We propose a novel system based on the Floating Mass Transducer (FMT) to be used as the active component of a fully implantable, Vibrant Soundbridge-like middle ear implant. The new system replaces the external microphone used in the currently available design with an implantable piezoelectric sensor that is inserted into the incudostapedial joint and picks up the vibrations transmitted to the long process of the incus. The FMT is coupled to the round window of the cochlea. We characterize the system by measuring the gain in intracochlear sound pressure using laser Doppler vibrometry at a surgically installed “third window” into the cochlea of six temporal bones. Closed-loop feedback oscillations limit the system's available output. We show that using an adaptive control algorithm, a mean functional gain of up to 40 dB is achieved, which is similar to Soundbridge functional gain. The concept matches the FMT's one-point fixation philosophy and offers several advantages over other designs, namely an easy and time-efficient surgery, reversibility of implantation, and natural hearing for the prospective patient.

Evaluation of one-point fixation for zygomaticomaxillary complex fractures using a three-dimensional photogrammetric analysis

BackgroundThe goal of treatment for zygomaticomaxillary (ZM) complex (ZMC) fractures is to achieve stability and restore aesthetic appearance through three-dimensional reduction and rigid fixation. The purpose of this study was to evaluate the stability and aesthetic appearance outcomes of one-point fixation using a three-dimensional photogrammetric analysis.MethodsFrom March 2014 to December 2014, 34 patients with ZMC fractures were treated by one-point fixation in the ZM buttress using unsintered hydroxyapatite (u-HA)/poly-L-lactide (PLLA) plates. Differences in soft tissue inter-malar height between the fractured side and unfractured sides were evaluated using photogrammetric analysis with a three-dimensional camera (Morphius®) at the preoperative and 1 week, 1 and 3 months after surgery. The differences in bony inter-malar height between the fractured and unfractured sides were evaluated using computer tomography at the pre-operative and 6 months after surgery. The paired t-test was used to compare differences in malar height.ResultsSix months after surgery, 34 patients achieved satisfactory bony stability and symmetric malar appearances. Comparisons of differences in soft-tissue inter-malar height revealed statistically significant differences between the pre-operative period and 1 week and 1 month after surgery (p < .01). There was no statistically significant difference between 1 and 3 months after surgery. Comparison of differences in bony inter-malar height revealed a statistically significant difference between before and 6 months after surgery (p < .01).ConclusionsWhen we conducted a three-dimensional photogrammetric analysis, although it has restricted surgical indications, one-point fixation of the ZM buttress using an u-HA / PLLA plate yielded reliable, satisfactory, and safe clinical results in patients with ZMC fractures.Clinical question / level of evidenceTherapeutic, III.

Reasons for plate removal after treatment of orbitozygomatic complex fractures

PurposeThe purpose of this study was to assess numbers of patients that required removal of miniplates after open reduction and internal fixation of the orbitozygomatic complex over a six-year period, and review the reasons for removal. Patients and methodsThis was a retrospective study from February 2007 to December 2013. All patients who had open reduction and internal fixation for traumatic orbitozygomatic complex fractures were included and those who returned to theatre for plate removal were identified. Results307 plates were placed in 216 patients. Eight plates were removed from six patients giving a 2.6% incidence of plate removal (2.78% of patients). Infection or exposure occurred within the first year in five out of six patients, accounting for the seven buttress plates, which were in situ for an average of 180 days. The infraorbital plate was in situ for 972 days. The majority of plates used were buttress plates as single point fixation. ConclusionsIn our experience placement of buttress plates for one-point fixation of traumatic orbitozygomatic complex fractures seems to be a safe and effective method with a low rate of complication. Complications seem to occur within a year, which is similar to previous studies.

Posterior atlantoaxial three-point fixation: comparison of intraoperative performance between open and percutaneous techniques

Atlantoaxial instabilities, which require surgical fixation follow a variety of clinical disorders. Different surgical procedures are used for stabilization of the atlantoaxial complex, mainly posterior wiring techniques and transarticular screw fixation. Nowadays, often a combination of transarticular screws and a posterior one-point fixation is used to achieve a three-point fixation, with superior biomechanical stability and good clinical results. Different modifications were developed to improve this technique. In 1995, a percutaneous approach for atlantoaxial stabilization was introduced. In clinical studies, the technique showed a tendency towards better outcome. Beside the outcome, the intraoperative performance is of special interest for minimal invasive approaches. We therefore compared the operation time, screw angulation and blood loss, between the open and percutaneous posterior atlantoaxial techniques. Two groups, each consisting of 17 patients, with either open (group 1) or percutaneous (group 2) atlantoxial stabilization, were compared. The operation time was retrospectively acquired from the patient's charts. The data for blood loss was provided by our anaesthesiological department, separated for intraoperative, postoperative and total blood loss. Screw angulation was measured on the postoperative x-ray by an orthopaedic surgeon. The percutaneous group showed an average intraoperative blood loss of 239.7 ml, compared to 929.4 ml for the open group (p< or =0.001). The analogue values for the postoperative blood loss were 142.9 ml and 379.4 ml for group 2 and group 1, respectively (p=0.008). Consecutively, the total blood loss showed also a statistically significant difference (p< or =0.001). The operation time was significantly different (p< or =0.001), with average values of 175.3 min (group 1) and 110.6 min (group 2). Screw angulation showed a trend towards a steeper angulation in the percutaneous group with an average angle of 56.8 degrees , compared to 53.9 degrees (group 1), although this was not statistically significant (p=0.053). The percutaneous technique for atlantoaxial stabilization with a three-point fixation has clear intraoperative benefits, with shorter operation time and reduced blood loss. A trend towards steeper screw angulation was found and shows at least equal feasibility for transarticular screw placement with the percutaneous technique, compared to the standard open approach.

Biomechanical Test Comparing the Load to Failure of the Biodegradable Meniscus Arrow Versus Meniscal Suture

Summary: The biodegradable Meniscus Arrow (Bionx, Blue Bell, PA) is a newly introduced method for repair of meniscal injury. However, because of a lack of studies, there is still little understanding of its biomechanical behavior. Biomechanical test was carried out to evaluate the load to failure and failure modes of the Meniscus Arrow and to compare the results with those of three traditionally used methods. Thirty-five lateral menisci obtained from Yorkshire pigs were incised longitudinally, simulating a peripheral longitudinal tear, and were repaired by means of Meniscus Arrows (one-point and two-point fixation), as well as with the techniques of knot-end, horizontal, and vertical suture using No. 1 PDS II monofilament suture. Tensile strength testing was performed according to each repair method with the Instron tensometer (Model No. 5569; Instron, Canton, MA) and its results were analyzed using a computerized statistical program. The average maximal tensile strengths were 113.9 ± 14.6 N in vertical suture, 75.1 ± 18.4 N in horizontal suture, 53.9 ± 6.4 N in knot-end suture, 38.3 ± 4.3 N in one-point fixation Meniscus Arrow repair, and 56.5 ± 3.5 N in two-point fixation Meniscus Arrow repair. The initial failure strength for two-point fixation Meniscus Arrow repair is comparable to that of a knot-end suture. Following the results of this study, meticulous caution should be taken when meniscal tears are repaired with Meniscus Arrows. Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 15, No 7 (October), 1999: pp 726–732

Zygomatic Fractures

We have analyzed different methods of internal fixation of simple displaced fractures of the zygoma in an attempt to define the simplest method(s) of achieving postreduction stability. Twenty-five combinations of interfragmentary wiring and miniplate and screw fixation of fractured zygomas on human skulls were compared for postreduction rotational stability against stresses simulating the muscular forces that act to displace the zygoma once it has been reduced. Analysis of the data suggests that while three-point fixation using either miniplates or interosseous wires allows for virtually no displacement, two-point fixation and in some cases one-point fixation provide acceptable stability. In general, stable fixation is achieved by methods that involve the use of at least one miniplate and incorporate the frontozygomatic suture line as one of the points of fixation.

The Internal Skeletal Fixation System

A new internal skeletal fixation system (ISFS) for stabilizing thoracolumbar fractures and other spinal disorders was developed by Dick in Switzerland. The ISFS is a modification of the Magerl external skeletal fixation system of the spine. The Dick modification consists of a threaded rod connected by clamps to Schanz screws and is located in the vertebral pedicles on both sides of the spine. Due to a stable angle between the rod and Schanz screw, a one-point fixation above and below the diseased vertebra is sufficient. The ISFS provides a short fixation and promotes fusion. Control of lordosis, kyphosis, and rotation of the spine is possible with threaded rod distraction and compression and through manipulation of the Schanz screws held by movable clamps. The advantage of the ISFS is the ability to achieve reduction and fixation with the same instrumentation. ISFS has been used in more than 90 patients and proven most adequate for thoracolumbar fractures and other localized spinal disorders. The Harrington system and its modifications are no longer in use for these problems.